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CONTENTS

Introduction

Background

Development,PoliticsandTheWhizzKids

Construction

ItFlies!

ToWork–ToTest

TheDemiseofAV/2

SoHowDidItFly?

BlackbirdsAndSukhois

TheXB-70andtheUSSST

Retirement

XB-70FlightLog

Abbreviations

Bibliography

ACKNOWLEDGEMENTS

Aprojectofthisnaturecouldnotbeundertakenwithoutconsiderable help from many organizations andindividuals. Special thanks must go to Tom Brewer,formerlyoftheAirForceMuseumFoundataionInc,andlatertheNationalMuseumoftheUSAirForceformuchhelp and assistance over the years. Thanks also to thestaffoftheJohnFKennedyPresidentialLibrary,thestaffoftheLyndonBJohnsonPresidentalLibrary,thestaffoftheAir ForceHistorical Studies Office, the staff of theNASAHistoryOffice,theHistoryOfficeofEdwardsAirForce Base, North American Aviation, and NorthAmericanRockwell.

Theauthorisindebtedtomanypeopleandorganisationsforprovidingphotographs for thisbook,manyofwhichare in the public domain. In some cases it has not beenpossible to identify the original photographer and socredits are given in the appropriate places to theimmediatesupplier. Ifanyof thepictureshavenotbeencorrectlycredited,theauthorapologises.

INTRODUCTION

The first time anyone sees the sole surviving XB-70AValkyrie it’s hard not to be struck dumb by the jaw-droppingly amazing shape of this totally futuristicotherworldlylookingaircraft.

Firstly,it’shuge.Theaircraftisfivetimesheavieranda whole lot larger than the MiG 25 fox bat or SR-71Blackbird, the design’s nearest rivals. Secondly it looksfast.ThefirsttimeIsawAirVehicleOnewasoutsidetheUSAF Museum (as it then was) at Wright Field, nearDaytonOhio, in1980-it lookedasif itwasabout togosupersonic justparked there!At the time itwasplayingoneofapairof‘bookends’outsidethemainbuildingtoalater generation Rockwell B-1 ‘Bone’ and the Valkyriestilllookedthemoreadvanced!

Thirdly, the aircraft was one very big leap-into-the-futuredesignthatpushedtheenvelopeintermsofexoticmaterials used -such as stainless steel honeycomb, verylarge amounts of titanium, the use of tool steel forstructural components and it would have used thechemical high energy ‘zip’ fuel if that had not beencancelled.

Atonestage-ifalltheplansandrhetorichadcometofruition-therewouldhavebeen250Valkyriesintheair-

the pinnacle of General Curtis LeMay’s quest for theultimate strategic bomber operated by his Strategic AirCommand.

IthasbeensaidthatthebeginningoftheXB-70storywasthesearchforanuclear-poweredbomber-thatstartedwith a highlymodified Consolidated B-36 Peacemaker,thedesignofwhichcamefromWorldWarTwowhenitlookedasiftheUSAwouldhavetofightatwofrontwarfrombasesonlyonthemainland.TheB-36wasthefirstinterimbomber,replacedalmostassoonasitappearedbytheBoeingB-52Stratofortress, itself the second interimdesign,albeitjet-powered,butitwasstillsubsonic.

ThesolesurvivingXB-70wasretiredtotheAirForceMuseuminFebruary1969andspentmanyyearsoutsideintheharshOhioclimate.(author)

62-0001wasre-paintedinthe1980s,andposesherefortheobligatory‘MuseumPortrait’.(USAF)

The Convair B-58 Hustler came out of thepreliminary studies and was supersonic -but at best itcould only be called a medium bomber and was toomuch, too soon. It became amaintenance nightmare, asanycrewchieffromthetimewilltellyou.

WhatGeneralCurtis LeMaywantedwas amachinewiththespeedoftheB-58andtheload-carryingcapacityof the B-52 -andwithout doubt the B-70 looked like itwouldfulfillhisneeds.WhatLeMaygotwaspossiblythebiggest fight he ever had experienced -with RobertMcNamaraandhisteamof‘WhizKids’.Thissmall,eliteband of civilians, who had mainly moved over fromeither the RAND Corporation or the Ford MotorCompany and went right to the heart of the John FKennedy and Lyndon B Johnson presidentialadministrations.TheWhizKids inventedaworldwherealldecisionscouldbemadebasedonnumbers -an idealthat is still skirted on by many MBA programs andconsulting firms. They found power and comfort in

assigning values to what could be quantified anddeliberatelyignoredeverythingelse.

TheB-70wascutbacktotwoexperimentalaircraft-withthepossibilityofafurthermachine,asaprototypetothe ‘Reconnaissance Strike’ concept. It was also to beusedasatestaircraftintheAmericanego-driven‘Machnumber too far’ SuperSonicTransport thatwas doomedtofailure.

Of the two built, one was lost -and two highlyexperienced test pilots were killed -during whatpoliticians called an illegal flight, despite the same typeofeventhappeningmanytimesbefore.

The revealed story is one of ambition, dreams,spying, and dirty pool politics on Capitol Hill – sonothingunusualtherethen!

‘Cecil thesea-sickseaserphent’mayhavebeenoneof the silliest nicknames ever given to an aircraft, butwhatanaircraft,whatashape,whatadesign!

GrahamMSimonsPeterborough,England

BACKGROUND

Itwasthe1950s.ElvisPresleywasrockingtheworldwithHoundDog,TheKingsofRythmfeaturingaguitaristcalledIkeTurnerhadalreadysmokedupastormwithRocket88,SenatorJosephMcCarthysawRedsundereverybed and Cadillacs had tail fins that grew larger and longer with everymodel.Itwasatimeofcontrastingoptimism,paranoiaandconsumerism–andtheUnitedStatesofAmericawasaimingatbecomingtheworld’sonlysuperpower.

Meanwhile,onthedrawingboardsofNorthAmericanAviation(NAA)in Southern California, a new incredible design was taking shape for aMach3strategicbomber–theB-70Valkyrie.

TheconceptofstrategicbombinggoesbacktoHaroldLeeGeorge.AnAmerican aviation pioneer and an outspoken proponent of the industrialweb theory,George taught at theAir Corps Tactical School (ACTS) andthrough his teachings, influenced a significant group of airmen passingthrough it – oneswhowere to have powerful influences during and afterWorld War Two. He has been described as the leader of the so-called‘BomberMafia’, a group ofmenwho advocated an independentmilitaryarmcomposedofheavybombers.

GeorgestudiedaeronauticsatPrincetonUniversityandlearnedtoflyatLoveField,Texas,gettinghiswingson29March1918.HewenttoFrancethat September with an initial assignment to the 7th Aviation InstructionCenteratClermont.TwomonthslaterhewaspostedtotheMeuse-Argonnefront, piloting a bomber with the 163rd Bomb Squadron, 2nd DayBombardmentGroup.Intheoneweekthatitsawaction,the163rdflew69sorties. George observed that massed bombers, flying in formation,swampedenemydefencesandsoreducedtheattacker’scasualties.

InFrance,GeorgemetWilliam‘Billy’Mitchellandbecameconvincedthat Mitchell’s vision of an independent Air Force was the best futuredirectionfortheAmericanmilitary.

LieutenantGeneralHaroldLeeGeorge.(19July1893–24February1986)seenduringhislatteryears.GeorgewasoneofAmerica’sfirstproponentsofdaylightprecisionbombingbyan

independentairarm.(USAF)

Afterthewar,Georgewasassignedtothe49thBombardmentSquadronatKellyField,Texas,wherehewaspromotedtoFirstLieutenant inApril1921. He next served with the 14th Bombardment Squadron at LangleyField,Virginia, andwith theAberdeen ProvingGround,Maryland. From1921 to 1923, George assisted Mitchell in his bombing demonstrationagainst old battleships, and helped develop air-to-ship tactics. In August1925,GeorgewenttoWashingtonaschiefoftheBombardmentSectionintheUnitedStatesArmyAirCorpsOperationsDivision.

InJuly1929,GeorgewasorderedtoHawaiifortwoyearswiththe5thCompositeGroupatLukeField,servingPearlHarbor.InSeptember1931,hewenttoMaxwellField,Alabama,tostudyattheACTS,wherehehelpedrefine the precision daylight bomber doctrine taught there. Followinggraduation,GeorgebecameaninstructoratACTS,teachingairtacticsandprecisionbombingdoctrine and became de facto leader of the influential‘BomberMafia’.WithHaywoodSHansell,LaurenceSKuterandDonaldWilson, George researched, debated and finally codified what the menbelievedwould be awar-winning strategy thatWilson had termed as the‘industrialweb theory’. Thiswas amilitary conceptwhich stated that anenemy’s industrial power couldbe attacked at nodesof vulnerability, andthus the enemy’s ability towage a lengthywar could be severely limitedandhismorale–hiswilltoresist–broughtdown.

In 1934,Georgewasmade director of theDepartment ofAir Tactics

andStrategy,andvigorouslypromotedthedoctrineofprecisionbombing.Itwas throughhisdirectorshipofACTS, thatGeorgebecameknownas theunofficial leaderof themen in theUSAACwhoclosed ranksandpushedexclusivelytowardtheconceptofdaylightprecisionbombingasastrategic,war-winningdoctrineusingmassedairfleetsofheavybomberscommandedindependently of naval or ground warfare needs. This concept was toinfluencemore thanagenerationof thinkerswithin theUSAAC,USAAFandeventheUSAFand,apartfromaperiodwhentheUSAACadoptedtheRAF-styleareabombing tacticsusingB-29soverJapan thatcumulated inthe dropping of the two atomic bombs in August 1945, continued rightthroughtothe1970sandLinebackerIImissionsoverVietnam.Itwasalsotostronglyinfluencethedesignersandmanufacturersofbomberaircraft.

Georgewas promoted toMajor in July 1936. He graduated from theCommand and General Staff School at Fort Leavenworth, Kansas, thefollowing year and returned to Langley as commanding officer of theGeneral Headquarters (GHQ) Air Corps 96th Bombardment Squadron.George flew to SouthAmerica as a part of a series ofUSAACgoodwillflightsinFebruary1938andNovember1939.In1940,hetookcommandofthe2ndBombardmentGroup.

The industrialweb theorywasput into concrete formby theAirWarPlans Division. The plan was submitted for approval to the Joint Army-NavyBoardinmid-1941asAWPD-1,standingforAirWarPlansDivision,plan number one. A refinement to AWPD-1 came in August 1942 aftereightmonthsofdirectAmericaninvolvementinWorldWarTwo.ThenewplanwascalledAWPD-42andwas submitted to theCombinedChiefsofStaff. Neither AWPD-1 nor AWPD-42 were approved as combat battleplans or strategies – they were simply accepted as guidelines for theproduction ofwarmateriel necessary to carry out intended or subsequentplans. Finally in 1943, a plan was hammered out in meetings betweenAmericanandBritishwarplanners.Theindustrialwebtheorywouldbeputinto practical plan form with the Anglo-American Combined Bomberoffensive(CBO).

In the event, the industrial web theory failed to achieve its goals.Various targets were chosen and attacked serially, without evaluating theresults in light of their interdependence. American bombing leadersmaintainedthatprecisionattackswerebeingcarriedout,butinearly1944poor weather over Europe prevented visual sighting, and bombs were

droppedindiscriminatelybyinaccurateradarmethodsthroughcloudcover,resulting in general population destruction. By September 1944, allpretencetoprecisionwasabandonedwhenGeneralDwightD.Eisenhowerordered the area bombing of Berlin. By that time, bombing was not somuchstrategicasitwastactical,tosoftenGermanyforinvasionbygroundtroops. Thousand-bomber raids were not able to diminish industrialproductionofwarmateriel in time toprevent invasion, forwhenGermanarmsproduction finally faltered in the thirdquarterof1944,only30%ofthetotalofeventualbombtonnagehadbeendroppedonthecountry–thisafter the French-German border had been reached and the war on thegroundhadseenitsdecisivebreakthrough.

GeneralGeorgeChurchillKenney(6August1889–9August1977),thefirstCommanderofStrategicAirCommand.(USAF)

Germanywasconqueredbyinvasion;itdidnotsurrenderasaresultofbombing; the morale of the enemy was not significantly affected. NopopulationthatwasbombedinWorldWarTwolost theirwill toresist. Inthe Pacific, itwas the Emperor, not the people,who decided Japanmustsurrender.

Despite its failures in practice, the strategic bombing concept oftargetingcrucialindustrialbottlenecksbecamethefirstcoredoctrineoftheindependentUnitedStatesAirForcein1947.

StrategicAirCommandStrategic bombing proponents – in particular General Curtis E LeMay –continued to promote the doctrine into the nuclear age, formingStrategicAirCommand(SAC)tocarryoutavisionmodifiedtofittheneedsoftheColdWarandthethreatofnuclearwarfare.

SAC’soriginalheadquarterswasBollingField,theheadquartersofthedisestablished Continental Air Forces (CAF) in Washington, DC. TheheadquartersorganizationofCAFwasdesignatedStrategicAirCommand.Its first commander was General George C. Kenney. Ten days later,FifteenthAirForcewasassignedtothecommandasitsfirstNumberedAirForce. In June 1946 EighthAir Forcewas assigned. SACHQmoved toAndrewsAFB,MDon20October1946.

Itwascreatedwiththestatedmissionofprovidinglongrangebombingcapabilities anywhere in the world, but because of multiple factorsincluding themassive postWorldWarTwo demobilization andKenney’sunhappiness with being assigned to SAC, for the first two years of itsexistence, SAC existed mainly on paper. During this period, the UnitedStatesAirForceitselfwasestablishedon18September1947.Thesituationbegantochangewhenon19October1948,then-LieutenantGeneralCurtisLeMay–whowasonlyalowly1stLieutenant tenyearsearlier,suchwashis meteoric rise in rank – assumed leadership of the SAC. Soon aftertaking command, on 9November, LeMay relocated SAC toOffuttAFB,southofOmahaNebraska.ItwasundertheleadershipofLeMaythatSACdeveloped the technical capabilities, strategic planning and operationalreadinesstocarryoutitsstatedmissionofbeingabletostrikeanywhereinthe world. Specifically, during LeMay’s command, SAC embraced andintegrated new technological developments in the areas of in-flightrefueling,jetengines,andballisticmissilesintoitsoperations.

GeneralCurtisEmersonLeMay(15November1906–1October1990).LeMayhadastellarcareerintheAirForce.(USAF)

LeMayhadanumberofnicknames: ‘Boom-BoomLeMay’, ‘Old IronPants’, ‘Bombs Away LeMay’ and probably the most telling, ‘Old IronBalls’.DuringWorldWarTwohefoughtinboththeEuropeanandPacificTheatres,beforereturningtoEuropein1948toheaduptheAmericanpartoftheBerlinAirlift.

In1948,whenhereturnedtotheUSAtoheadtheSAC,itconsistedoflittle more than a few understaffed B-29 bombardment groups left overfrom World War Two. Less than half of the available aircraft wereoperational,andthecrewswereundertrained.WhenLeMayorderedamockbombingexerciseonDayton,Ohio,mostbombersmissedtheirtargetsbyatleast one mile. ‘We didn’t have one crew, not one crew, in the entirecommandwhocoulddoaprofessionaljob’notedLeMay.

The main fleets of combat aircraft that went to make up SAC wereConvair B-36 Peacemakers, Boeing B-47 Stratojets and Boeing B-52Stratofortresses.

ThemassiveB-36PeacemakerwasastrategicbomberbuiltbyConvairandoperatedsolelybytheUSAF.TheB-36wasthelargestmass-producedpiston engine aircraft ever made, although its six piston engines weresupplementedbyfourjetenginesintwopods.Ithadthelongestwingspanofanycombataircrafteverbuilt,230feet,althoughtherehavebeenlargermilitary transports. The B-36 was the first bomber capable of deliveringnuclear weapons that fitted inside the bomb bay without aircraftmodifications. With a range greater than 6,000 miles and a maximumpayloadof72,000lb, theB-36wasalso thefirstoperationalbomberwithan truly intercontinental range. The B-36, including its GRB-36, RB-36,andXC-99variants,wasinserviceaspartoftheSACfrom1948to1959.

The Boeing B-47 arose from a informal 1943 requirement for a jetpowered reconnaissance bomber, drawn up by the USAAF to promptmanufacturerstostartresearchintojetbombers.Boeingwasoneanumberofcompanies to respond to this request,with its initialdesign, theModel424, basically a scaled-down version of the piston-engined Boeing B-29Superfortress, but equipped with four jet engines. During the followingyear, this concept evolved into a formal request-for-proposal to design anewbomberwithaspecifiedmaximumspeedof550mph,acruisespeedof450mph,arangeof3,500milesandaserviceceilingof45,000ft.

Sixturningandfourburning–Consolidated’senormousB-36Peacemaker.(USAF)

Theinteriorofapreviousgenerationsix-enginedbomber–theConsolidatedB-36,thisexamplebeing52-2220whichispreservedattheNationalMuseumoftheAirForceinDayton,Ohio.(author)

After the design had passed through numerous stages, the USAAFfinallyplacedanorder inApril1946for twoprototypes, tobedesignated‘XB-47’.AssemblybeganinJune1947andthefirstXB-47wasrolledouton 12 September. The XB-47 prototype made its first flight on 17December1947with thetestpilotsRobertRobbinsandScottOslerat thecontrols.SACwastooperateB-47Stratojets(B-47s,EB-47s,YRB-47sandRB-47s)from1951through1965.

Beginningwith the successful contract bid on 5 June 1946, theB-52Stratofortressdesignevolvedfromastraight-wingaircraftpoweredbysixturbopropenginestothefinalprototypeYB-52witheightturbojetengines.Theaircraftfirstflewon15April1952with‘Tex’Johnstonaspilot.Builtto carry nuclearweapons forColdWar-era deterrencemissions, theB-52Stratofortress replaced theConvairB-36.Althoughaveteranofanumberof wars, the Stratofortress has dropped only conventional munitions in

combatandcarriesupto70,000poundsofweapons.ItsStratofortressnameis rarelyusedoutsideonofficialuse; ithasbeenreferred tobyAirForcepersonnelastheBUFF–BigUglyFatFucker,andisstillinserviceintheseconddecadeofthe21stcentury.

Upon receiving his fourth star in 1951 at age 44, LeMay became theyoungestfour-starGeneralinAmericanhistorysinceUlyssesS.Grantandwastheyoungestfour-starGeneralinmodernhistoryaswellasthelongestservinginthatrank.In1956and1957LeMayimplementedtestsof24-hourbomberand tankeralerts,keepingsomebomber forces readyatall times.LeMay headed SAC until 1957, overseeing its transformation into amodern, efficient, all-jet force. LeMay’s tenure was the longest over amilitarycommandinclosetoahundredyears.

The historical record indicates that LeMay advocated justified pre-emptive–or theso-called‘FirstStrike’–nuclearwar.Severaldocumentsdating from the period during which he commanded SAC show LeMayadvocatingpreemptiveattackoftheSovietUnion,haditbecomeclearthattheSovietswerepreparingtoattackSACand/ortheUnitedStates.Inthesedocuments,whichwereoftenthetranscriptsofspeechesbeforegroupssuchas theNationalWarCollege or events such as the 1955 Joint SecretariesConferenceat theQuanticoMarineCorpsBase,LeMayclearlyadvocatedusing SAC as a pre-emptive weapon if and when such was necessary.However,unlikepopularbelief thathasgrownupover theyears, there islittle evidence to suggest that LeMay ever advocated an unauthorized orunjustifiednuclearattackontheSovietUnioninthemannerofarenegadeofficer launching a nuclear attackwithout Presidential permission.To thecontrary, aDecember 1949 letter fromLeMay to theAir Force Chief ofStaffGeneralHoytVandenberg indicates thatLeMaywasconcernedwithhavingexplicitauthority fromthenation’spolitical leadership to launchapreemptivestrikeagainsttheSovietUnion.Thisletter,inLeMay’sfilesattheLibraryofCongress,showsLeMaybeingunwillingtooperateoutsidetheauthorityaffordedhimasamilitaryofficerandthathealsorecognizedtheconstitutionalrolepoliticalleadershipplayedinthedecisiontoinitiatewar.

TheBoeingB-47Stratojet.(USAF)

LeMaywasappointedViceChiefofStaffoftheUnitedStatesAirForceinJuly1957,servinguntil1961,whenhewasmadethefifthChiefofStaffoftheUnitedStatesAirForceontheretirementofGenThomasWhite.Hisbelief in the efficacy of strategic air campaigns over tactical strikes andground support operations became Air Force policy during his tenure asChiefofStaff.

AsChiefofStaff,LeMayclashedrepeatedlywithSecretaryofDefenseRobertMcNamara,AirForceSecretaryEugeneZuckert,andthechairmanof the Joint Chiefs of Staff, ArmyGeneralMaxwell Taylor.At the time,budget constraints and a number of successive nuclear war fightingstrategieshadleftthearmedforcesinastateofflux.Eachoftheforceshadgradually jettisoned realistic appraisals of future conflicts in favour ofdeveloping its own separate nuclear and non-nuclear capabilities. At theheight of this struggle, the US Army had even reorganized its combatdivisions to fight landwars on irradiated nuclear battlefields, developingshort-rangeatomiccannonandmortarsinordertowinappropriations.TheUnitedStatesNavy in turnproposeddeliveringstrategicnuclearweaponsfrom supercarriers intended to sail into range of the Soviet air defenseforces.Ofall thesevariousschemes,onlyLeMay’scommandstructureofSAC survived complete reorganization in the changing reality of postwarconflicts.

TheBoeingB-52Stratofortress.(USAF)

AnapologyIt is from this point that the reader is forced to enter the confusing andmurky world of military initialisms, jargon and acronyms that was sopopularinthe1950sand60s.TheUSdefenceestablishment–bothcivilianand military – seems to have loved reducing names, departments andorganisations down to a confusing set of letters during this time. Thereappearstohavebeennouniversalagreementontheprecisedefinitionofthevariousterms,norintheirwrittenusage.Itseemsthattheyusedindividualletters or parts ofwords to create new, shortened ‘words’ that have beenlisted in a glossary elsewhere; most are mercifully short. We should bethankfulthattheB-70wasfortheUSAirForce,otherwisethisbookmightinclude ADCOMSUBORDCOMPHIBSPAC, which was a United StatesNavy term that supposedly stands for ‘Administrative Command,AmphibiousForces,PacificFleetSubordinateCommand’!

FindingaB-52replacement–thefirstcompetition.Itwasduringhisnine-yeartenurewithSACthatLeMayhelpedshapethedevelopment of America’s strategic all-jet bomber force. LeMay’s visionwas focused on the future – the 1965 to 1975 time period, when the jetbomberscurrentlyinservicewouldneedtobesupplementedandultimatelyreplacedbynewertypesduetotheirobsolescence.

LeMay began to plan requirements for a new jet- powered bomberweaponsystem,onewiththerangeandpayloadoftheB-52andthespeedof theB-58, theworld’s first supersonicbomber,capableofMach2dashspeed.Hewasconvincedthatsuchabomberwas technicallyfeasibleandhepursueditscreation.

TheConvairB-58Hustler.(USAF)

AlthoughConvair’sB-58wasmoreadvancedandfasterthanBoeing’sB-52, it was ordered into production as a supplement rather than areplacementandwasalsoregardedasbeingobsoleteinthetimeperiodof1965-75.

SAC–andLeMayinparticular–sentHeadquartersUSAFaseriesofrequirement letters, calling for the development of a mannedintercontinentalheavystrategicbomberweaponsystemtofollowtheB-52.It was presumed that the proposed bomber would be a ‘split mission’aircraft that would fly subsonically like the B-52 to the enemy earlywarningline,then‘dash’supersonicallyliketheB-58tothetarget.Itwouldthenwithdrawfromthetargetareasubsonically.

On 14 October 1954, HQ USAF published General OperationalRequirement (GOR) No. 38 for a Piloted Intercontinental StrategicBombardment Weapon System. As GOR 38 stipulated, the advancedbomberwas tobe all-chemical-fueled,was to fully replace theB-52, andwas to be active in SAC inventory in the 1965-75 timeframe. The AirForce,theNationalAdvisoryCommitteeonAeronautics(NACA–nowtheNationalAeronauticsandSpaceAdministration(NASA)),andsixselectedairframecontractorshadstudied thisproposedweaponsystemforat leasttwo years under Secret ProjectMX-2145 before GOR 38 was publishedundertheformalStudyRequirement(SR)number22bytheAirForceAirResearchandDevelopmentCommand(ARDC).

GOR38identifiedWS(WeaponSystem)number110Aandestablished1963 as the target date for the first wing of 30 operational WS-110Abombers.SR22calledfor0.9Machcruisespeedand‘maximumpossible’dashspeedduringa1,000nauticalmilepenetrationasspecificperformanceobjectives. It stipulated that high-speed flight was not as important as

penetration altitude and radius. It further demanded that the proposedbomberwoulduseexistingSACbaserunwaysandmaintenancefacilities.Finally, theWS-110Awouldhave tocarrya25,000-poundpayload6,000nauticalmiles.

On22March1955,asecondGOR,GOR82,fortheWS-110Abomber,superseding GOR 38, was issued by HQ USAF. Then, on 15 April, arevisedrequirementwasissuedbyHQARDCtosupersedetheoriginalSR22 as SR 22 (Revised). The speed objective was modified slightly:‘...aircraftcruisespeedshouldnotbelessthan.9Machunlessasignificantincrease in maximum radius of action or time in a combat zone may beobtained. Maximum possible supersonic dash speed in a combat zone isdesired.”

On6April, theWeaponSystemProjectOffice (WSPO)forWS-110Awas established as part of the Bomber Aircraft Division, Directorate ofSystemsManagement,DetachmentNo.1,HQARDCatWright-PattersonAFB,Dayton,Ohio.During the period from 6May through 12 July, theWS-110AWSPOpresentedabriefingtoHQAMC,HQARDC,HQSAC,AirForceAirStaff,AirForceAirCouncil,andtheDepartmentofDefense(DoD),outlining itsproposedprogramme todevelopanddeliver theWS-110A bomber at Wing strength by 1963. It was proposed that theoperational air vehicles be preceded by one static test article and 20flight/service test aircraft. On 21 June, the Deputy Chief of Staff forDevelopment directed thatWS-110Adevelopment be initiated as soon aspossiblewithamultiple,competitivePhaseOneprogramme.

Prior to this, in early 1955, HQ USAF issued GOR 96 for anintercontinentalstrategicreconnaissancesystemthathadsimilarobjectivestoWS-110A. Then on 1 July HQ ARDC issued a study requirement insupportofGOR96whichestablishedareconnaissanceversionoftheWS-110A, identified at the time as WS-110L (confusingly the ‘L’ meantreconnaissance).Thebomberandreconnaissanceweaponsystemprogramswerelatercombined,andtheprojectwasthenidentifiedasWS-110A/L.

A few days later, on 13 July, a joint AMC/ARDC Source SelectionBoard put forward a list of six airframe contractors—Boeing, Convair,Douglas, Lockheed, Martin, and North American – all of whom wereeligible for consideration for thedevelopmentof theWS-110A/Laircraft.Of these six, only the Boeing Aircraft Company and North AmericanAircraft,Inc.chosetosubmitproposals.

Boeing’sanswertotheWS-110Astudy.TheModel724-13usedapairofModel724-1001‘floating’wingstocarryextrafuel,thatwerelaterdiscardedasthemissionprogressed.(USAF)

NorthAmericanAviation’soriginalWS-110Adesignproposal.

Theouter‘wings’completewithtankswereusedduringthesubsonicpartofthemission,thenjettisoned.

The‘broadarrow’canardwasthoughttorestrictaircrewvisibilitytoomuch,especiallyduringtake-offandlanding.(USAF)

Boeing and North American each received Phase One WS-110engineering contracts as prime WS-110A/L contractors on 8 November1955.Amonthearlier,on11October,HQARDCissuedAmendmentNo.1toSR22(Revised),whichchangedthetargetdateforthefirstoperationalthirtyaircraftWS-110wingfrom1963toJuly1964.Theschedulewasnowfor full-scale engineering mockup inspection to take place in November1957,firstflightinMarch1960,andequipageofthefirstSACWing,withthefirstoperationalproductionaircraft,byDecember1963.

Fourmonthsafter theawardofcontracts inApril1956,bothairframecontractors submitted their respective WS-110A/L preliminary designproposals.Forundisclosedreasons,duetoasecretre-evaluationofGOR96byHQARDCon27April1956,workontheWS-110A/Lreconnaissancesystem was ordered to be held in abeyance and was not subsequentlyrevived.Thereasonforthiswasnotrevealedformanyyears:itwasthetwo‘black’projectsfor thehighlysecretLockheedSkunkWorks, theU-2spyplaneandlaterA-12/SR-71aircraft.

TheWS-110Astudies fromBoeingandNorthAmerican–alongwiththeUSAFevaluation–wereput together into apresentationgiven to thecommandersof theAMC,ARDC,SAC,andHQUSAFoveraperiod26May through to 13 June 1956. A briefing at HQUSAF on 13 June wasattendedbyGeneralsCurtisE.LeMay,DonaldL.Putt,EdwinW.Rawlings,andClarence‘Bill’Irvine.ThiswasfollowedinJulybyteamsconducting

on-site evaluations at Boeing and North American who reported theirfindingstothesecondSourceSelectionBoardon10August.

On 18 October 1956, due to the reviews of WS-110A, HQ USAFordered thatPhaseOnedevelopmentbediscontinuedbut thatBoeingandNorth American were permitted to continue their studies on a reducedresearch and development schedule. The programme was effectivelycancelledatthistimeasadirectresultoftheAirForce’sdisappointmentinboth Boeing’s and North American’s studies. Neither company hadproduced a satisfactory design – both designs were colossal, incrediblycomplexandveryoverweight.Tosatisfyrangeandpayloadrequirements,bothcompaniessuggestedthattheairvehiclemightweigh750,000poundsor more, and that it would require giant disposable outer wing panels,termed‘floatingwingtips’tosupplyfuelfortheoutgoingtripthatweighedsome 190,000 pounds each. Their respective top speeds after discardingtheirwingtips – the so-called ‘dash’ speeds–wasprojected at 2.3Mach.General LeMay in particular was upset. He reportedly exploded at onemeeting: ‘Back to the drawing boards. These aren’t airplanes—they’rethree-shipformations!’

Boeing’s initial WS-110A design, its Model B-724, featured a basicaircraftcomprisingafuselage,bicyclelandinggearsimilartothatoftheB-47andB-52,wing,verticaltail,fourturbojetengines,canardforeplane,andfloating wing panels. The floating wing extensions attached to the basicairplane’s own wingtips and featured large bullet-shaped fuel pods, eachabout the length, diameter, and weight of a B-47’s fuselage, their ownvertical and horizontal tails for stability, and expendable takeoff landinggear.

North American’s first WS-110A proposal, its Model NA-239, alsoshowed the floating wing panel configuration. However, the NA-239featuredtwinverticaltails,sixturbojetengines,andalargearrowhead-likecanardforeplanethatwouldhavereducedforwardanddownwardvisionbysome50%.

As split-mission bombers – subsonic cruise-supersonic dash – bothdesignsweretotakeoffintheirthree-partmode,topofftheirfuelsuppliesviainflightrefueling,cruiseatMach0.9and60,000feettowardtheirpre-planned target, jettison their spent wing panel fuel pods, dashsupersonicallyat2.3Machtoandawayfromtheir target,reducespeedto0.9Mach,andreturnhometothenearestfriendlyairbase.

Artist’simpressionsduringthelate1950sandearly1960swerealwaysvery‘spacey’showingdarkskies,curvatureoftheearthandrocketexhausts.HereaNorthAmericanartistdepictsasingle-tailed

aircraftwithasingleeitherchemicaloratomicengine–butclearlyitisonewithmanyB-70influences.(NAARockwell)

ThecurvedhorizonsuggestsnearspaceasthisValkyrieinfullafterburnerlaunchesamissilefromitsweaponsbay.(NAARockwell)

Itwassuggested that therewereanumberof techniques thatcouldbeusedtoincreaserange–theuseofHighEnergyFuels(HEF),theuseofaBoundaryLayerControl(BLC),theuseofadvancedaerodynamics,andtheuseofhigh-cycleenginespossiblywitha re-design theaircraft to takeonboardtheAreaRuleTheory.

‘Area Rule’, sometimes termed the ‘Whitcomb area rule’ or thetransonicarearule,isadesigntechniqueusedtoreduceanaircraft’sdragattransonicandsupersonic speeds,particularlybetweenMach0.75and1.2.ThearearulewasdiscoveredbyOttoFrenzlwhencomparingasweptwingwithaw-wingwithextremehighwavedragwhileworkingonatransonicwind tunnel at Junkers works in Germany between 1943 and 1945. Hewroteadescriptionon17December1943,with the title ‘ArrangementofDisplacementBodiesinHigh-SpeedFlight’;thiswasusedinapatentfiled

in1944.The results of this researchwere presented to awide circle inMarch

1944byTheodorZobelat theDeutscheAkademiederLuftfahrtforschung(GermanAcademyofAeronauticsResearch)inthelecture‘Fundamentallynew ways to increase performance of high speed aircraft’. The designconcept was applied to German wartime aircraft, including a rather oddMesserschmitt project, but their complex double-boom design was neverbuilteventotheextentofamodel.Severalotherresearcherscameclosetodevelopingasimilartheory,notablyDietrichKüchemann,whodesignedataperedfighterthatwasdubbedthe‘KüchemannCokeBottle’whenitwasdiscoveredbyU.S. forces in1946. In thiscaseKüchemannarrivedat thesolution by studying airflow, notably spanwise flow, over a sweptwing.Thesweptwingisalreadyanapplicationofthearearule.

Anartist’simpressionofthere-designedNAAWS-110AprojectthatisclearlyB-70.(NorthAmericanRockwell.)

MoreB-70artwork–thistimeshowingthenon-blendedforwardfuselagetomainbodydesignthatthemock-upalsoexhibitedalongwithnosignofthefoldingwing-tips.NotealsotheSACsash

wrappingaroundthefuselagejustaftofthecanards.(TheAeroplaneandAstronautics)

IntheUSAWallaceD.Hayes,apioneerofsupersonicflight,developedthe supersonic area rule inpublicationsbeginning in1947withhisPh.D.thesisattheCaliforniaInstituteofTechnology.

Richard T Whitcomb, after whom the rule is named, independentlydiscoveredthisrulein1952whileworkingatNACA.WhileusingthenewEight-Foot High-Speed Tunnel at NACA’s Langley Research Center, hewassurprisedbytheincreaseindragduetoshockwaveformation.SeveraldayslaterWhitcombhada‘Eureka’moment.Thereasonforthehighdragwas that the ‘pipes’ of air were interfering with each other in threedimensions.Herealisedthat itwasnotpossible tosimplyconsider theairflowingoveratwo-dimensionalcross-sectionoftheaircraftasotherscouldinthepast;nowtheyalsohadtoconsidertheairtothe‘sides’oftheaircraftwhichwouldalsointeractwiththesestreampipes.Whitcombrealizedthatthe Sears-Haack shaping – that is an aerodynamic body shape with thelowesttheoreticalwavedrag–hadtoapplytotheaircraftasawhole,ratherthan just to the fuselage.Thatmeant that theextracross-sectionalareaofthewingsandtailhadtobeaccountedforintheoverallshaping,andthatthefuselageshouldactuallybenarrowedwheretheymeettomorecloselymatchtheideal.

AnothercompetitionA secondWS-110A competition followed. Both companieswent back totheirdrawingboardsandsliderulesbeforeon1July1957theysubmittedfurther reports before attending another round of briefings toHQUSAF,HQAMC,HQARDC,andHQSAC.BothcontractorsconcludedthatwithHEF, specifically, a high-energy chemical fuel called boron in the engineafterburner section, the proposed WS-110A could be an all-supersonic-cruiseairvehicle.

NorthAmerican,hadaddedafurtherrefinementtoitsprojectthatdealtwith advanced aerodynamics. It was called compression lift. Inaerodynamics,compression lift refers toanaircraft thatusesshockwavesgenerated by its own supersonic flight to generate lift. This can lead todramatic improvements in lift for supersonic/hypersonic aircraft, whichoftenflyathighaltitudesandthussufferfromdecreasedliftduetothethin

air. Clarence A. Syvertson and Alfred J. Eggers, two NACAaerodynamicists, discovered this phenomenon in 1956 as they analyzedabnormalitiesatthere-entryofnuclearwarheads.

The basic concept of compression lift is now well known; ‘planing’boatsreducedragby‘surfing’ontheirownbowwakeinexactlythesamefashion.Usingthiseffectinaircraftismoredifficult,however,becausethe‘wake’inairtakestheformofshockwavesthataregeneratedatsupersonicspeeds,andthesecouldbeemployedtoproduceadditionallift,butonlyifthey are highly angled. Aircraft have to be carefully shaped to take fulladvantage of this effect. In addition the angle of the shockwaves variesgreatlywithspeed,makingitevenmoredifficulttodesignacraftthatgainssignificantliftoverawiderangeofspeeds.

Neither Boeing nor North American knew of this aerodynamicdiscovery in the first competition, but a later search through NASA’sscientific periodicals by three North American aerodynamicists – EdWendt,ArtLey,andDaveBeck–brought theconcept to light–and intouse.

Both organisations had overhauled their respectiveWS-110A designsand could now claim a continuous 3.0Mach – or 2,000mph – cruise at70,000feetormorealtitude,adoublepayloadof50,000pounds,andanun-refuelledrangeof7,600nauticalmiles.

Boeing’snewWS-110AChemicallyPoweredBomber(CPB)appearedas its Model B-804, a 200- foot-long delta-wing design with variablegeometry(VG)canardforeplanes.Boeing’s rejuvenatedstudiesofaircraftconfigurations, exotic fuels, aerodynamics, metallurgy, and power plantsprescribed the use of six podded, underwing General Electric X-279Eturbojetenginesratedto4.0Mach.Maximumtakeoffweighthaddroppedtoanacceptable500,000pounds.

To take full advantage of NASA’s compression lift, North Americanlikewisereconfigured, theirWS-110ACPB,ModelNA-259,nowfeaturedlarge deltawingswithVGwingtips thatwere folded down for increasedstabilityandliftathighsupersonicspeeds.Itretaineditscanardforeplane,but this was relocated to the area aft of the cockpit windows, thuseliminatinginterferencewithpilotvision.Itstillsportedtwinverticaltailsanditsengines–alsosixGeneralElectricturbojets–werelocatedside-by-side in a huge boxlike structure below but integral with the aft fuselagesection and wing junction. It was also fitted with a two-position VG

windscreen—downforlow-speedandupforhigh-speedoperations.On 30 August 1957, HQ USAF started a forty-five day competitive

design period that peaked with on-site inspections of the contractor’sfacilities by a Source Selection Board evaluation group. Since bothcompanies had failed to satisfy theAir Forcewith their initial three-partdesigns,aPhaseOne,PartTwocontestfortheWS-110ACPBwasagreedto.

GeneralThomasSarsfieldPower(1905–1970)(USAF)

On1July1957GeneralThomasS.Power,whohadbeenLeMay’sViceCommander in SAC from 1948 to 1954, now became SAC’S newCommander inChief.Since1954,GeneralPowerhadheaded theARDC.LeMay became U.S. Air Force Chief of Staff. Power had in-depthknowledgeofbomberaircraftandwaswell informedabout theWS-110ACPB programme. He was also knowledgeable about the IntercontinentalBallistic Missile (ICBM) programmes, which were becoming more andmore ‘popular’ as a relatively low cost and more simplistic option intargetting theenemy–especiallywith thepoliticians.Power’s jobwas tocreateamixedbomberandmissileforceforSAC–twolegsofAmerica’stripod of manned bombers and land-based ICBMs, the US Navy’ssubmarinescreatingthethirdleg.

TheSourceSelectionBoardevaluationgroup–sixtyofficersandmenfromSAC,AMC,andARDC–descendedonNorthAmericantoreviewitsnewWS-110ACPB proposal during the lastweek ofOctober.ABoeingreview was conducted the following week. On 27 November, the teamcaptains representing the trio of Air Force commands reported theirfindings in a briefing presided over by Gen. LeMay to the threecommanders of SAC, AMC, and ARDC at Wright-Patterson AFB.

Recommendationsfromthethreecommanders—Gen.ThomasS.Power,General EdwinWRawlings, andGeneral JohnW Sessums Jr were thensubmittedinsealedenvelopestotheSecretaryoftheAirCouncil.

AnAtlasICBMofSACismaintained‘combatready’atVandenburgAFBinCalifornia.Itshydrogenbombwarheadisattached,andsitsreadytobefiredatfifteenminutesnotice.Itwasthiskindof

missilethattheB-70wasupagainstinthedecisionstakes.(USAF)

Thislookslikeaphotograph,butitisinfactmoreB-70artwork.AgainthereistheSACsashwrappingaroundthefuselagejustaftofthecanardsandnowthehintofalinedenotingthefolding

wingtips.ThedateisNovember1960.(TheAeroplaneandAstronautics)

When the envelopes were opened, the North American proposal hadbeen judged to be superior by a considerable margin. Gen. Irvine statedbeforetheAirCouncilthattheWS-110ACPBsourceselectionexercisehadbeenthemostthoroughandthemosteffectivecompetitioneverconductedbytheUnitedStatesAirForce.

On 23 December 1957, the long-awaited decision came down. HQUSAFannouncedthatNorthAmericanAircrafthadbeenselectedasWS-110A CPB prime contractor. Simultaneously, AMC and ARDC weredirected to determine the degree to which the programme could beacceleratedinanefforttoequipthefirstSACbombwingwithWS-110Asattheearliestpossibledate.

Boeing,seenbythemselvesastheundisputedleaderinbomberaircraftdesignandproductionsinceatleast1940withitsB-17,B-29,B-50,B-47,andB-52aircraft,couldnotbelieveoracceptthedecision.AswiththeKC-Xrefuellingtankersagaofrecentyears,Boeingimmediatelycalledforandgot a congressional inquiry in an effort to have the decision overturned.However, it was determined that NAA’s design had a far better lift overdrag(L/D)ratio,anditwasthiswhichhadconvincedtheAirForce.

Boeing had been advised to investigate NASA’s Compression LiftTheory, which it did in a somewhat half-heartedmanner. They remainedhighlyscepticalanddidnot thinkNAAsrevisedL/Dfigurewasvalid,orthattheirdesignwouldreachitsstatedperformancegoal.

The AMC and ARDC, along with North American, investigated theprogrammeaccelerationproblemandfound thatan18-monthaccelerationtothecurrentschedulewaspossible.AbriefinggiventoGeneralsLeMay,Anderson,Putt,andIrvineon4January1958recommendedprocurementofthe entireweapon system,with the exceptionof thepowerplant, throughNAA under Category I. It was also recommended that the engine beprocured from the General Electric Company at Evendale, Ohio, underCategoryII.ThesetworecommendationswereapprovedbyHQUSAF,anda letter contract (AF33-600-36599)was signed on 24 January 1958.Thisaction officially established NAA as the weapon system contractor andGeneralElectricasthepowerplantcontractor.

DEVELOPMENT,POLITICSAND‘THEWHIZZKIDS’

Now the contracts were issued, both NAA and GE had much to do –especiallyas theWS-110ACPBprogrammehadbeenmovedupeighteenmonthstomeettheAirForce’snewprojectedInitialOperationalCapability(IOC).At the time, theAirForceandSAC intended toprocurea fleetof250WS-110A CPB bombers at an estimated cost of $6 billion. GeneralElectricwouldhavetoproduceatleast1,500enginesfortheseaircraft,plusspares.

The Defense Department issued a more standard B-for-Bomberclassification to the WS-110A CPB, so it became the B-70 CPB on 6February 1958. SAC andARDC attended one of the B-70CPBWeaponSystemEvaluationConferencesatNorthAmericanduring theweekof14Apriltorevisethedesignconceptoftheproposedairvehicle,toincreaseitsdesign gross take off weight so as to fully utilize its onboard load andvolumecapabilitiesandtoreducetheprobabilityofretrofitsbeingrequiredinthefuture.Thisdoubledtheaircraft’spayloadto50,000poundsandgavethemachineanothermissionofMissilePlatformBomber(MPB),similartotheupcomingBoeingB-52GandB-52HMPBaircraft.Theconferencealsoincorporatedtheuseofdecoymissilesintoitsdefensivesubsystems.

NAA initiated its subcontracting project for the B-70 in May 1958;thousandsofcompaniesinnearlyeverystateoftheUnionweretoshareintheB-70CPBeffort.Forexample, theaircraft’sAN/ASQ-28(V)bombingand navigation and missile guidance subsystem would be built byInternationalBusinessMachines(IBM);BeechwouldmaketheAlertPodsubsystem; Boeing, the wing; Westinghouse, the defensive subsystem;NorthAmerican’sColumbus,Ohio,facility,thelowerfuselage;Lockheed,the upper fuselage; Sperry, the auxiliary gyro platform; Motorola, theAN/ASQ-43MissionandTrafficControl(M&TC)subsystem;Autonetics,the automatic flight control subsystem;Zenith, thenose radome;Chance-Vought,thecanardforeplanesandverticaltails;Sundstrand,thesecondarypower generating subsystem; John Oster, power plant instrumentation;ClevelandPneumatic,thelandinggearassemblies;HamiltonStandard,the

air inductioncontroland theenvironmentalcontrolsubsystems;Solar, theengine extraction air ducting;AiResearch, the central air data subsystem;and BF Goodrich, the brakes, wheels, and tires for the landing gearassemblies. Many hundreds of other subcontractors around the countrywerealsoinvolved.

What’sinaname?The company started to look around for a name for the new design anddecided that through the SAC publicity office a ‘name-the-plane’ contestwouldbeheld.Fromthe20,235entriesthename‘Valkyrie’wasofficiallyapprovedon27June1958;andwasannouncedpubliclyon3JulyjointlybytheAirForce,SAC, andNorthAmerican.Thewinnerof the contest.AirForceT/SgtFrancisW.Seller,wasoneof13entrantstosubmitthenameinthesix-weekcontest,butSeller’sentryhadtheearliestpostmark–3April.In Norse mythology, a valkyrie – taken from Old Norse valkyrja the‘chooseroftheslain’–isoneofahostoffemalefigureswhodecidewhowilldie inbattle.Thevalkyries–attested in thePoeticEdda, -bring theirchosentotheafterlifehalloftheslain,Valhalla,ruledoverbythegodOdin,where the deceasedwarriors become einherjar. There,when the einherjararenotpreparingfortheeventsofRagnarök,thevalkyriesbearthemMead,a beer-like drink. Valkyries also appear as lovers of heroes and othermortals, and are sometimes described as the daughters of royalty,sometimesaccompaniedbyravens,andsometimesconnectedwithswans.

The first of theB-70CPBWeaponSystemDevelopmentEngineeringInspections(DEI)tookplaceatNorthAmericanfrom2Marchthrough11March 1959.During thisDEI, 761Request ForAlterations (RFAs)werewrittenbythe159attendingUSAFparticipantsrepresentingallcommands.After a review of all RFAs by a team ofAir Force andNorthAmericanpersonnel, only 381 RFAs were considered Category 1-type changes, orthosetobeaccomplishedaspartofthecurrentcontractualrequirements.

TwodifferingviewsofhowNorthAmericanAviation‘marketed’theB-70.Aboveisaverydramaticpaintingofavalkyrieonhersteed,completewithStrategicAirCommandcrestonhershield.

TheWeaponSystemmockupreviewtookplacefrom30Marchthrough4April1959.Thefull-scaleengineeringmockupreviewdifferedfromtheDEI in that it was styled to present the operational characteristics andsuitability of the configuration and the general arrangement of theoperational article presented, rather than detailed system analysis andtheory.A totalof50RFAswerewrittenby the47AirForcepersonnel inattendance.

BelowaCalifornianvalkyriemeetstheB-70Valkyrieinscalemodelform.(bothNorthAmericanAviation)

HighenergyfuelsandtheB-70As already mentioned, after preliminary investigations by several

companies, the use of high energy fuels in air-breathing turbojets hadseemed a likely possibility of increasing the power-output of aircraftengines,withnumerousspecialfuelsbeingconsidered.Metalslurries–inparticular magnesium – and liquid hydrogen received some attention,especially from Lockheed, who spent a considerable time on thedevelopmentofahydrogenpoweredaircraft–calledtheCL-400andtwicethesizeofaB-52–undertheirownProjectSunTan.

Researchsuggestedthatalkylboranefuelsofferedthegreatestpromise.Weighing approximately the same as conventional fuels and occupyingabout the same volume, the boron-based fuels were expected to produce40%more energy than standard JP-4, (Jet Petroleum)whichwas jet fuelblended from50%keroseneand50%gasoline.Theeventualboron-basedhigh energy fuels included: HEF-1, ethyldiborane; HEF-2,propylpentaborane; HEF-3, ethyldecaborane; HEF-4, methyldecaborane;HEF-5,ethylacetylenedecaborane.

After investigation, itseemedthatalkylboraneproductscouldserveastheonlypropellantorasadditivestostandardfuels.Theirusecouldalsobelimited to only the afterburner – thought to be the easiest immediateimplementation–ortheycouldbeusedintheprimarycombustor,althoughthisapproachwouldtakeacompletere-evaluationofthehot-sectionoftheengine.Highenergyfuelspromiseda16%rangeimprovementoveranallJP-4 mission when the new fuels were used only in the afterburners.Researchsuggestedthatenginesusingboronfuelsintheprimarycombustorandafterburnerwouldhavea30%rangeimprovement.

The Power Plant Laboratory had conducted some experiments usingboronfuelsinrepresentativeafterburners,butalackofsufficientquantitiesof the fuels for useful testing led the laboratory to abandonment of thetrials.OnlyGeneralElectricgaveanyindicationofseriousinterestinhighenergyfuelafterburnerdevelopment;Pratt&Whitneystatedthatithadnointerest inalkylboranefuelsuntilmoreof theproblemareasweredefinedandresolved.

The confusing definition of the WS-110A systems led to a strongrequirement for some sort of range extension, and boron fuels seemed toofferarelativelyeasysolution.Althoughtheywouldrequirealargelynewinfrastructure,includingadedicatedtankerfleet,theywouldallowthenewbombers to conduct their final refuelingwell outsideSoviet airspace, andrequirefewertankerspermission.

However,duringtheearly1950s,nobodyhadthecapabilitytoproducethealkylboranefuelsinlargequantity.Asmallpilotplantwasconstructedthatproduced0.8 tonsperdaybymid-1957,withproduction rising to25tonsperdayoverthenexttwoyears.Facilitiesneeded$8millioninFiscalYear(FY)56,withanadditional$12millionrequiredforeachofthethreesucceedingyears.

Themilitaryinterestinboronfuelsspurreddevelopmentofarelativelyunknown field, since boron chemistry was very complex and differedconsiderably from other fields. General Electric was one of the firstcompaniestoconductaninvestigationofboroncompoundsasspecialfuels,beginning in the mid-1940s. About the same time, the Navy Bureau ofAeronauticsalsobeganstudyingboronhydrides.Itwasnotuntil1952thattheBureauofAeronauticslaunchedaboronfuelprogramme–ProjectZIPconducted by the Callery Chemical Corporation and the OlinMathiesonChemicalCorporation.This led toHEFbecomingknownas ‘zip fuels’ inmost later literature. Callery began producing small amounts of aalkylborane–calledethyldecaborane–inNovember1953.Meanwhile,GEwascontinuingitsresearchasasubcontractortoOlinMathieson.

TheAir Force awarded a $178,000 contract toGeneral Electric for asmall-scale fuel evaluation known as Project DASH to determine thethermodynamic characteristicsof boronoxide exhaust products.AlthoughGeneralElectric’searlyresearchwassomewhathamperedbyalackoffuel,bytheendof1957theyhadconcludedthat theuseofhighenergyfuel inthe afterburner of an engine was feasible. This early work accomplishedconsiderable advances in useful materials, definition of design problemareas, fuel properties, and new data on exhaust products andthermodynamics.

Thetacticalandstrategicvaluesofthenewfuelswereapparent,butthishadtobebalancedagainstsuchseriousproblemsastheproductionoffuels,predicted handling difficulties, and high production costs impeded theirutilization.Basicresearchrevealedthatoneofthemostcriticalproblemsinburningboronfuelswastheformationofboronoxidedepositsthatprovedto be an excellent flux for certainmetal oxides, limiting the constructionmaterialsthatcouldbeused.Boronoxidewasaviscousliquid,meltingatabout900°F,andfluidtotemperaturesover3,000°F.Thesolidandliquidexhaust products, however, could be quite harmful to the workingcomponents of high performance engines and could greatly reduce

operatingefficiencyandlongevity.InMarch1957theAirForceHeadquartersreceivedahighenergyfuel

evaluationprogrammereport.Thisplanemphasized thedevelopmentofaturbojetwithanafterburnerthatusedthenewfuel.Itwasorientedaroundrequirements to support WS-110A. The report stated that a qualifiedafterburnerwasexpectedin1962andamaincombustorin1963.

Soon after North American became the weapon system contractor inlate1957, theB-70ProjectOffice reiterated itsbelief thatHEF-3was themosteconomicalmethodtoachievethedesired15%rangeincreaseoveranallJP-4mission.GOR82wasrevisedon7March1958toincludeastudyofallmethodsofrangeextensiontoachieveanun-refueledrangeof11,000nauticalmiles.The range augmentation effected through theuseofHEF-burning in the J-93 afterburnerwas on the order of 10%while the rangeincreasethroughtheuseofonein-flightrefuelingviaaBoeingKC-135wasabout20%.Somewhat surprisingly,highenergy fuelwasnevera specificrequirement for the B-70 programme, although the use of HEF-3 in theafterburnerandtheresultantdual-fuelcapabilitytohandleJP-4andHEF-3didbecomeanintegralpartoftheearlyB-70design.

The development of new alloys or resistant coatings was imperative.Numerousmeetingswereheldin1958tosolvethisfundamentalproblem.Theresultsoftheseconsultationsindicatedthatanalloycouldprobablybedeveloped forunstressedenginecomponentsoperatingat temperaturesupto 2,300° F, and a silicon bearing or silicate refractory coating fortemperaturesoverthisfigure.

Theseinquiriesestablishedthatmostmetallicmaterialshadlittleeffectupon HEF-3, although some lead and copper alloys could catalyze fueldecomposition.EvenmoredisturbingthoughwasthatHEF-3wastentimesmoretoxicthancyanide,necessitatingthedevelopmentofspecialhandlingand storage techniques. This toxicity also raised questions regarding thefuel’s use by operationalmilitary units, but itwas expected thatmethodscould be found to mitigate the hazard. The low spontaneous ignitiontemperaturerequiredanitrogenatmosphereinallareasofthefueltanks,aswellasanitrogenpurgeofallemptyfueltanksandlines.

TheHEF-3 fuel alsohad thenastyhabit of tending to solidify after atime at high temperatures, and the presence of moisture and oxygenaccelerated this decomposition; however, itwas thought that bulk fuel inairframe tanks would probably not reach temperatures high enough for

thermal decomposition to become a problem. Little additional thermaldecompositionwouldoccurwhenthefuelpassedthroughhightemperaturezones in thefuelsystem,butresidual fuel that remained in tanksorstoodidleinfuelsystemscouldeasilyreachsolidificationtemperatureinashorttime. In-flight flushingwithJP-4wasapossibleanswer,but that requiredthatthetwofuelswerecompatible.

While petroleum fuels required relatively simple refining operations,crudeboronmixtureshadtobemanufacturedfrombasicchemicalsbeforetheycouldberefined.Theseextrastepsimposedasubstantialcostpenaltyon production of high energy fuels, and the additional electric powerrequired further increasedcosts.Oneestimateheld that a10 tons-per-dayproductionfacility tosupportoneB-70WingwithHEF-3wouldcost$35milliontobuild.

Bythe timetheB-70becameoperational,highenergyfuelproductioncostsperpoundcouldbereducedto$1.50orso,stillverymuchhigherthanJP-4at$0.02perpound(abouttencentsagallonin1964dollars).However,in terms of performance gains, the new fuels use – and costs – could bejustified.

On12February1959RichardEHomer,AssistantSecretaryoftheAirForce for Research andDevelopment, called for a change in special-fuelpriorities,suggestingthattherewasan‘apparentneed’tostudyfurthertheapplicationofhighenergyfuel to theB-70,andrecommendingadelayintheconstructionofadditionalfuelproductionfacilities.

SAC’s reaction to this recommendationwas emphatic.GeneralPowerurgedon25March1959thatnoactionbetakentodiverthighenergyfuelprioritiespending thecompletionof studieshis commandwasmakingonthesubject.Hestatedthatitwouldbeunwisetointerrupttheprogrammeatthe very time it was gaining momentum from developmental successes.GeneralPoweralsostated that theuseofhighenergyorJP-4 in theB-70engineafterburnerhadalwaysbeenpartofthebasicdesign.

General Samuel E Andersen, Commander of the Air MaterielCommand,secondedthispositionon1May1959,whenhecalledupontheAirForceChiefofStaff forafirmcommitmentregarding theuseofhighenergyfuelsoverthenextsevenyears.GeneralAndersonpointedoutthatafivetons-per-dayproductionfacilitywouldbeoperativebyJuly1959,butthis plant could not supply the needs of operational B-70 bombers. Heanticipatedthatproductioncostscoulddropto$1perpoundforfull-scale

production and he called for an immediate decision on firm high energyfuelrequirementstoprovide‘...maximumflexibilityandoveralleconomy’.

GeneralSamuelEAndersen,(1906–12September1982)commanderoftheAirMaterialCommand,Wright-PattersonAirForceBase,Ohiofrom10March1959to1April1961.(USAF)

In contrast to Secretary Homer’s recommendation, the B-70 ProjectOfficeon24February1959urgedSACtomakea‘realisticevaluation’ofthe B-70’s operational advantages with high energy fuel, since the AirForce programme would soon come to the point where further directionwasnecessary.TheProjectOffice remindedSAC that budgeting for highenergyfuelproductionfacilitieshadtobeaccomplishednolaterthanFY60so that engineering and construction could begin by January 1961. TheProjectOfficeunderscored the inter-relationshipof timelyfuelproductionandasuccessfulhighenergyfuelengineprogramme,notingthatthelatterwas,inFebruary1958,aheadofschedule.

Delays inmaking high-level decisions on the fuel programme led theAirMaterielCommandattheendofApril1959tonotifyNorthAmericanofa sixmonth slippage in the J93-GE-5engineprogramme.By this timeNorthAmericanhadalreadyconvertedthesecondweaponsbayintoextrafueltankagetoenabletheearlyB-70stomeettheirrangerequirementusingthenewJP-6fuelthenbeingproduced.

Afterstudyingfeasibilityandcostdata,inlateMaySACrecommendedthat firstallocationsofhighenergyfuelshouldaimatqualificationof theJ93-GE-5engine, that the firstB-70operationalWing shouldhave the -5(rather than the -3) engine to avoid costly future modifications, and thathigh energy fuel – though its costwas competitive – should not excludeother means of range extension. Noting that the B-70 should exceed

minimum range requirements even with the new JP-6, SAC emphasizedthat the new fuel would allow greater target coverage, heavier payloads,better penetration routes, a choice of recovery bases, andmore adequatelandingreserves.

On8July1959theARDC,AMC,andSACmadea jointpresentationonhighenergyfuelstotheAirForceWeaponsBoard.Theboardchairman.ColonelJCJennison,recommendedacontinuedauthorizationofJ93-GE-5enginedevelopment, inclusion in theFY61budget roundof funds for thefirst10-tons-per-dayfuelfacility,anallocationof$3.75millionforanall-HEF engine development feasibility study in FY60, and the provision of$27.6 million in FY60 for fuel purchases to support the current enginedevelopmental programme.Therewere no recommendations, however, tocommittheB-70tohighenergyfuels.

On16 July1959HQUSAFauthorizedpurchases of thenew fuels inFY60,buton10AugustthePentagondrasticallyreducedtheoverallscopeofthehighenergyfuelandcancelledtheJ93-GE-5engineprogramme.Themotiveswerevague,butcitedagenerallackofinterest,fiscalconstraints,and environmental concerns. Cancellation of the -5 engine limited B-70planningtoanengineusingonlyJP-typefuels,andthisrestriction in turnforced North American to embark upon a redesign of the B-70’s fuelsystem.

ThisactionwasinterpretedbythemediaandthepublicasapreliminarymovethatforetoldthetotalcancellationoftheB-70CPBWeaponSystem.Itwasnotgenerallyknown,norwasitclarifiedforthebenefitofthepublic,that the YJ93-GE-3model engine being produced under contract for theXF-108LRI,wassimilarinthrustoutputandslatedforuseinthebomber.Infact,thefirstairvehiclewasscheduledtobeequippedwiththe-3modelengineevenbeforethe-5modelenginewasaxed.

As designed, the -3 model engine would burn JP-6, and did notincorporateHEF-burninginitsafterburnersection.Astheresultofdesignimprovementscomingfromcontinuouswindtunnel testing, thecalculatedrangeoftheB-70hadreachedapointwhereHEFwasnolongerrequiredtomeet theminimum range requirement.TheHEFprogrammecancellation,asitrelatedtotheB-70programme,wasalmostablessingindisguise,foritresultedintheremovalofconsiderablefuelsystemcomplexity,andreducedtheprojectedoperationalcosttremendously.

CancellationandtheriseofICBMsOn3December1959,America’sairarm,reachingtowardthe1965-75timeperiod,wasseveredatthewrist.MauriceH.Stans,budgetdirectorfortheEisenhower Administration, who extolled the virtues of ICBMs, wasfrantically searching for a way to balance the budget during PresidentElsenhower’sfinalyearinoffice.Heseizeduponthetaskforcestudythathadindicatedthatalong-termreassessmentofthemannedbomberairplaneprogramme was in order. The Air Force subsequently announced thecancellationoftheB-70WeaponSystemanddirectedNorthAmericanandtheB-70WSPOinDaytontotakestepstore-orienttheprogrammetowardthedevelopmentofasingleXB-70prototypeonly.

Subsystemswerecanceledandsub-contractswereeitherterminatedorredirected to other aircraft programmes.Only theXB-70prototype,YJ93engine,bombingandnavigationandmissileguidancesystem,landinggear,secondary power generating system, air induction control system, engineextractionairdualingsystem,environmentalcontrolsystem,andcentralairdata system continued to be developed. Moreover, the lone XB-70prototype was re-scheduled to first fly in January 1963, with continuedflighttestingthroughtheyear1967.

In the 1950s and early 1960s ICBMs emerged as a reliable weaponsystemoptionthatcostafractionoftheirmannedcounterparts.Theirlowerinitialcost,coupledwiththefactthattheyneedednohumancrew,stronglyenticedmilitary planners.As the consequence, themissile-versus-bomberdebateswereborn.

Pro-missile supporters argued that the lower cost, near-pinpointaccuracy,intercontinentalrange,andquickstrikeICBMswerefarsuperiortomannedbomberaircraft.Thoseinthepro-bombercampcounteredwiththe fact thatmanned bomber aircraft could be recalled after launch; theysubmittedthatonceanICBMwaslaunched,itwascommittedtostrikeitsprogrammedtarget,thatitcannotchangeitsrobotmind.Furthermore,theyjustifiedthatsinceanICBMrequiredonlyamere30minutesorsotoreachitstarget,therewouldnotbeadequatetimeforanywar-savingnegotiations,that an all-out nuclear confrontation could ensue. These arguments grewheatedandpersistedformanyyears.

MauriceHubertStans(22March1908–14April1998)wasanAmericanaccountant,high-rankingcivilservant,Cabinetmember,andpoliticalorganizer.HewasapoliticalservantforanumberofAmericanPresidentsandwasaperipheralfigureintheensuingWatergateScandal.Hewasalsothe

personthatkilledofftheB-70asaweaponssystem.

GeneralTwining,aformerAirForcechiefofstaff,arguedthattheAirForce needed the B-70 to penetrate the Soviet Union to search out anddestroymobileICBMsonrailroadtracks.‘Ifthey[theAirForce]thinkthis,theyarecrazy’repliedEisenhower.‘WearenotgoingtobesearchingoutmobilebasesforICBMs;wearegoingtobehittingthebigindustrialandcontrolcenters’.

Aseriesofpersuasivearguments– inparticular thosemadebyUSAFChiefofStaffThomasDWhiteandUSAFDeputyChiefofDevelopmentRoscoeCWilson–ledtothereallotmentofmoniesbyCongressfortheB-70programme.

GeneralWhitepresentedtheAirForce’scasefortheB-70.Thenationcould not relywholly onmissiles, none ofwhich had ever been fired incombat.Missiles could not be recalled, as aircraft could. Bombers couldstand off and remain airborne while awaiting orders, thus giving thePresident a range of options in a crisis. Bombers would complicate theenemy’s problem, forcing it to defend against several different kinds ofattack.Finally,theB-70bomberswouldactasademonstrationofmilitarymightandhaveapowerfulpsychologicaleffectonfriendandfoealike.

By1960itwasoft-quotedthatone-thirdoftheSACbomberforcecouldbe airbornewithin fifteenminutes of theword being given; thiswas thewarningperiodexpectedforanICBMattack.SACwerealsoplanningforanairbornealertforce;inotherwords,aproportionofSACbomberswould

alwaysbeairbornesothattheycouldnotpossiblybecaughtontheground.Under the SAC ‘positive control’ system, the B-70 bombers were to

take-offwhenanattackwarningwasreceivedandheadforenemytargets.They could be recalled at any time if thewarningwas a false alarm, butwouldturnroundata‘positivecontrol’pointunlesstheyreceivedspeciallycodedorders, the so-called ‘gocode’, to continue.Nuclearweaponswerenot armed until the bomberwas ordered to attack; co-ordinated effort byseveralcrewmemberswasneededtoarmtheweapons.

GeneralDwightDavid‘Ike’Eisenhower,34thPresidentoftheUSA(14October1890–28March1969)

Itwasclaimed thatneitherbombersnor ICBMscouldbe launchedonanattackwithoutPresidentialauthority.Thismeant thatICBMscouldnotbefireduntilafterenemyweaponshadlanded,becausethemissilescouldnotberecalledinthesamewayascouldthebombers.

Many people wereworried that a nuclear warmight be triggered offaccidentallyby,say,anewsatelliteormeteoritewhichwasinterpretedasanICBMaimedattheUS.Inthethinkingofthetime,onejournalistreportedthat ‘... it is very reassuring to be told, as I was last year at SACheadquarters and this year in the Pentagon, that American militaryauthoritiesacceptthepossibilityofseveralnuclearwarheadshittingtheUSwithout triggeringoffanautomaticmassiveretaliation’. Idonot thinkhewasbeingironic!

Another study showed that ifmajorU.S. citieswere attacked by 250megatons of nuclear weapons, less than half their population would becasualties.Coldly,thenumber-cruncherssaidthatthetotaldeath-tollmight

be20millionpeople,whichneednotnecessarilybecripplingtoanationof180million.

The report went on to state that ‘Fall-out is not considered to be asdangerous as often thought. If a country were subjected to a massivenuclear attack, much of its population could survive merely by stayingindoors for several days; and the fall-out effect on the rest of theWorldwould not be serious.Nuclearwar is considered possiblewithout endinglifeontheEarth.

In fact,attacksoncitiesandpopulationsarenowconsidered tobeanunsophisticatedwayofusingnuclearweapons,even in retaliation.Targetdiscrimination is needed, and it is considered pointless to indulge in apopulation-killing contest. The counter-force argument is based onattackinganenemy’smilitaryforcesandability;citieswillonlybeattackedwhentheyhappentocontainmilitarytargetssuchasheadquarters’.

On31July1960,Congressapprovedanadditional$75million,therebyincreasingtotalFY61appropriationsto$365million.Thisamountmadeitpossible forNAA to complete theXB-70 prototype, build one static testarticle, reinstate all subcontractor programmes, and produce 12 fullyoperationalB-70s.

With ICBMs such as Convair’s Atlas, Martin’s Titan, and Boeing’sMinuteman under development in concertwithBoeing’sB-52G/HMPBsandNorthAmerican’sB-70,themixedforceconceptwassettobecomeareality. Clearly the politicians had decided that both types of weaponsystemswereneeded.

EisenhowerrespectedGeneralWhite,bothforhis leadership inWorldWar Two and for hiswide-ranging intellect. But the President also knewthat White was pressing him as the official representative of a largebureaucraticInstitutionwithitsownvestedinterestsatstake.ThePresidentdidnotacceptWhite’smilitaryrationalefortheB-70.HetoldtheAirForcechiefofstaffthatthebomberrolewasservedadequatelybytheB-52,andbythetimetheB-70wasreadyitsrolewouldbefilledbymissiles.

GeneralThomasDresserWhite(6August1901–22December1965)thefourthChiefofStaffoftheUnitedStatesAirForce.

Achangeofideology,aclashofcultureWithhiselectionasthe35thPresidentoftheUnitedStates,itwasnotlongbefore JohnFKennedy issuedacontroversial announcementon theB-70programmefromtheWhiteHouse.

On 2 November 1960 as Senator Kennedy, he gave a speech at theHortonPlaza,SanDiego,duringwhichhesaid:‘...Thisyear,asaresultoftheeffortsbySenatorEngleandothers,theCongressoftheUnitedStatesappropriated$300millionfortheB-70’s.IendorsewholeheartedlytheB-70mannedaircraft.Wecouldnotgettheadministrationtoreleasethefundsuntilthisweek.Thatisprogress’.

Fourmonthslaterafterhiselection,KennedyeffectivelysoundedtheB-70’sdeathknellasanoperationalbomberwhen,followingthedirectionofhis Secretary ofDefense, Robert SMcNamara, the President released anofficial statement in March 1961, which said in part that America’sforthcoming ICBM capabilities ‘...makes unnecessary and economicallyunjustifiablethedevelopmentoftheB-70asafullweaponsystem’.

The35thPresidentoftheUSA,JohnFitzgerald‘Jack’Kennedy(29May1917–22November1963)

The President further recommended that the B-70 programme ‘...becarriedforward,essentiallytoexploretheproblemsofflyingatthreetimesthespeedofsoundwithanairframepotentiallyusefulasabomber,throughthe development of a small number of prototype aircraft and relatedbombingandnavigationsystems’.

Defense Secretary McNamara stopped NAA’s B-70 production go-ahead inApril1961,andonlyauthorized theconstructionof the threeairvehicles, which were to be completed not as bomber prototypes, but ashigh-speedaerodynamicresearchmachines.On10April,NAAreceivedarevised contract to build three XB-70 aircraft; the YB-70 service testversionwascanceled.On31July,the$365millionalreadyappropriatedbyCongressforFY61wastrimmedto$75millionandthefirstflightdateforthefirstaircraft,alreadysetback,wassetbackagain,thistimetoDecember1963.

RobertMcNamarawas born in San Francisco, California andwas anAmericanbusinessexecutiveandtheeighthSecretaryofDefense,whowasto serve under Presidents John F.Kennedy andLyndonB. Johnson from1961 to 1968. McNamara graduated from Piedmont High School inPiedmont,Californiain1933.Hegraduatedin1937fromtheUniversityofCalifornia,Berkeley,withaBachelorofArtsineconomicswithminorsinmathematics and philosophy. He then earned anMBA from the HarvardBusinessSchoolin1939.

McNamaraworkedayearfortheaccountingfirmPriceWaterhouseinSanFrancisco.InAugust1940hereturnedtoHarvardtoteachaccountingintheBusinessSchoolandbecamethehighestpaidandyoungestAssistant

Professoratthattime.Followinghisinvolvementthereinaprogrammetoteach analytical approaches used in business to officers of theArmyAirForces, he entered theArmedForces as aCaptain in early 1943, servingmost of thewarwith theAAF’sOffice of StatisticalControl.Onemajorresponsibility was the analysis of U.S. bombers’ efficiency andeffectiveness, especially the B-29 forces commanded by Major GeneralCurtisLeMayinChinaandtheMarianaIslands.Heleftactivedutyin1946withtherankofLieutenantColonelandwithaLegionofMerit.

SecretaryofDefenseRobertStrangeMcNamara(9June1916–6July2009)

In 1946 McNamara joined Ford Motor Company, owing to theinfluenceofCharles ‘Tex’Thornton, aColonel forwhomhehadworkedwhileinthemilitary.ThorntonhadreadanarticleinLifemagazinewhichreportedthatthecompanywasindireneedofreform.

McNamara was one of ten former World War Two officers knownwithinFordasthe‘WhizKids’,whohelpedthecompanytostopitslossesand administrative chaos by implementingmodern planning, organizationand management control systems. Starting as manager of planning andfinancial analysis, he advanced rapidly through a series of top-levelmanagement positions. Opponents argued that McNamara’s embrace ofrationalism–his seeming fetish fornumbers andcharts– impeded ratherthanenhancedhisabilitytocomprehendreality.

Afterhiselectionin1960,President-electJohnF.KennedyfirstofferedthepostofSecretaryofDefense to formersecretaryRobertA.Lovett;hedeclinedbutrecommendedMcNamara.KennedythensentSargentShrivertoapproachhimregardingeither theTreasuryor theDefensecabinetpost

less than five weeks after McNamara had become President at Ford.McNamara immediately rejected the Treasury position but acceptedKennedy’s invitation to serve as Secretary of Defense as long as thePresident gave assurances that McNamara had complete control of theDepartmentofDefense,subjectonlytothehigherauthorityofthePresidentascommanderinchief.

McNamarawasknowntohavenofondnessof themilitary ingeneral,or theAir Force in particular – he also had a low opinion of his formerboss, General LeMay. He frowned upon LeMay’s statistical accountingmethods and easily ‘found fault’ with the weapons systems favoured byLeMay.

This immediately put them in direct confrontation over the B-70project.McNamarathoughtthattoomuchmoneywasbeingspentonsuchweaponssystemsandgreatlypreferred toneatnessandapparenteconomyoftheICBMwithit’sattendanttheoryofMutuallyAssuredDestruction.

Although not especially knowledgeable about defense matters,McNamara immersed himself in the subject, learned quickly, and soonbegantoapplyan‘activerole’managementphilosophy, inhisownwords‘providing aggressive leadership questioning, suggesting alternatives,proposing objectives and stimulating progress’. He rejected radicalorganizational changes, such as those proposed by a groupKennedy hadappointed, headed by Sen. W. Stuart Symington, which would haveabolishedthemilitarydepartments,replacedtheJointChiefsofStaff(JCS)with a single chief of staff, and established three functional unifiedcommands. McNamara accepted the need for separate services but wasdetermined tooverhaul theDoD,arguing that ‘...at the endwemusthaveonedefensepolicy,notthreeconflictingdefensepolicies.AnditisthejoboftheSecretaryandhisstafftomakesurethatthisisthecase’.

Likealatter-daysvengali,RobertMcNamarasurroundedhimselfwithagroupof‘experts’fromtheRandCorporationthat inheritedthesomewhatdisparaging nickname of ‘The Whiz Kids’ that travelled over withMcNamara from the Ford Motor Company in order to turn around themanagement of the United States Department of Defense (DoD). Thepurpose was to shape a modern defence strategy in the nuclear age bybringing in economic analysis, operations research, game theory,computing, as well as implementing modern management systems tocoordinatethehugedimensionofoperationsoftheDoDwithmethodssuch

as thePlanning,Programming,andBudgetingSystem(PPBS).Thegroupincluded (among others): Harold Brown, Alain Enthoven, Patrick Gross,WilliamKaufmann,JanLodal,FrankNicolai,MertonJosephPeck,CharlesO. Rossotti, Henry Rowen, Ivan Selin, Pierre Sprey and AdamYarmolinsky.

TheWhiz Kids invented a world where all decisions could be madebasedon numbers – an ideal that is still touchedon bymanyMasters ofBusinessAdministration (MBA) programmes and consulting firms today.They found power and comfort in assigning values to what could bequantifiedanddeliberatelyignoredeverythingelse.

PresidentJohnKennedywithSecretaryofDefenseRobertMcNamaraon8July1961,inHyannisPort.McNamarawasoneofthefewmembersoftheAdministrationwhosocialisedwiththe

Kennedyfamily.

Perhaps it’s a hyperbole to say that they saved and then almostdestroyedtheUSA.ButtheKids’approachwouldultimatelycausethedropin quality and innovativeness of American cars, opening the door to theforeign invasion fromwhichAmerican automobilemanufacturinghas yetto recover. The Whiz Kids’ doctrine is also arguably responsible forAmerica’scontinuedinvolvementintheVietnamWarafter1965,whichledto thevastmajorityof thewar’s58,209UScasualtiesand themillionsofVietnamesemilitaryandciviliandeaths.Theyhadmanyoftherightideas.They brought analytical discipline to themilitary andAmerican businessthatdesperatelyneededit,but theyinadvertentlyswungthependulumtoofar.

The Rand Corporation (Research ANd Development) was set up in

1946 by the United States Army Air Forces as Project RAND, undercontracttotheDouglasAircraftCompany,andinMay1946theyreleasedthepreliminarydesignofanexperimentalworld-circlingspaceship.InMay1948, Project RAND was separated from Douglas and became anindependentnon-profitorganization.Initialcapital for thesplitcamefromthe Ford Foundation. Since the 1950s, RAND has been instrumental indefiningUSmilitarystrategy.TheirmostvisiblecontributionisthedoctrineofnucleardeterrencebyMutuallyAssuredDestruction(MAD),developedundertheguidanceofthenDefenseSecretaryRobertMcNamaraandbasedupontheirworkwithgametheory.

Thiswas–andis–abranchofappliedmathematicsthatisusedinthesocial sciences, most notably in economics, as well as in biology,engineering,politicalscience,internationalrelations,computerscience,andphilosophy.Game theoryattempts tomathematicallycapturebehaviour instrategic situations, orgames, inwhich an individual’s success inmakingchoices depends on the choices of others. While initially developed toanalyze competitions in which one individual does better at another’sexpense (zero sum games), it has been expanded to treat awide class ofinteractions,whichareclassifiedaccordingtoseveralcriteria.

Chief strategist Herman Kahn’s major contributions were the severalstrategies he developed during the Cold War to contemplate ‘theunthinkable’,namely,nuclearwarfare,byusingapplicationsofgametheory– he is often cited as the father of scenario planning. Kahn consideredEisenhower administration’s prevailing nuclear strategy of massiveretaliation, as being untenable because it was crude and potentiallydestabilizing.Arguably,the‘NewLook’invitednuclearattackbyprovidingthe Soviets with an incentive to precede any conventional, localizedmilitaryactionworldwidesuchasinKoreaorAfrica,withanuclearattackonU.S. bomber bases, thereby eliminating theAmericans’ nuclear threatimmediatelyandforcingtheU.S.intothelandwaritsoughttoavoid.

Chiefstrategist,aproponentofthewinnablenuclearwar,HermanKahn(15February1922–7July1983)

In1960KahnpublishedOnThermonuclearWar,inwhichherestedhistheory upon two premises, one obvious, one highly controversial. First,nuclearwarwasobviouslyfeasible,sincetheUnitedStatesandtheSovietUnioncurrentlyhadmassivenucleararsenalsaimedateachother.Second,likeanyotherwar,itwaswinnable.ThisledtoclaimsthatKahnwasoneofthe models for the titular character of Stanley Kubrick’s film Dr.Strangeloveor:HowILearnedtoStopWorryingandLovetheBomb.

Two ofMcNamara’swhizz-kidswould play a part in theB-70muchlater on. Harold Brown was initially Director of Defense Research andEngineering and later became Secretary of the Air Force. A forcefuladvocate of US nuclear testing, physicist Brown was SecretaryMcNamara’sprincipaltechnicaladvisor.OneAirForceofficerwhotangledwith him over the derailedRS-70 bomber programme said of him“He’sawfullycockyandsureofhimself.”AColumbiaPhDat21,Brownworkedthroughout the 1950s with the University of California’s RadiationLaboratory,wherehedidresearchinthedesignandapplicationofnuclearexplosives, the detection of nuclear blasts, and the controlled release ofthermonuclearenergy.

HenrySRowenwasDeputyAssistantSecretaryofDefenseforpolicyplanningandnationalsecurityaffairs,andalsocametoDefensethroughtheRand Corporation after graduating from MIT and studying at Oxford.PlannerRowenconcentratedonstrategicquestionsforthefutureratherthanday-to-day defence programmes. Articulate and wide-ranging in hisinterests—which could have been NATO or guerrilla warfare—RowenworkedatRandonabroadstudyofoverseasbasesthatturnedintoafull-dresscomparativereviewofUSvsSovietstrategicairpower.‘Assoonashe

touchesasensitivenerve,”saidanAirForceplanner,“..themilitarybegintoyell.Buthealwaysknowswhathe’stalkingabout.”

McNamara’sapproach todefensepolicyemphasizedsystemsanalysis.He averred that while the country could afford any level of expensedemandedbynational security, it shouldexamineallexpensesandensurethat taxpayer money was wisely spent. Numerical analysis favouredbreakingthingsdowntothelowestcommondenominatorandoptionswereconsideredcritically.

McNamara’s institutionof systemsanalysis as abasis formakingkeydecisions on force requirements, weapon systems, and other mattersoccasioned much debate. Two of its main practitioners during theMcNamara era, Alain C. Enthoven and K. Wayne Smith, described theconcept:‘First, theword‘systems’ indicates thateverydecisionshouldbeconsidered in as broad a context as necessary... The word ‘analysis’emphasizes theneed to reducea complexproblem to its componentpartsfor better understanding. Systems analysis takes a complex problem andsortsoutthetangleofsignificantfactorssothateachcanbestudiedbythemethodmostappropriatetoit’.

SecretaryoftheAirForceHaroldBrown.HeworkedunderRobertMcNamaraasDirectorofDefenseResearchandEngineeringfrom1961to1965,andthenasSecretaryoftheAirForcefrom

October1965toFebruary1969.

EnthovenandSmithsaidtheyusedmainlyciviliansassystemsanalystsbecause they could apply independent points of view to force planning.

McNamara demonstrated a tendency to take military advice less intoaccount than had previous Secretaries and to override military opinions.This contributed to his unpopularity with service leaders. It was alsogenerallythoughtthatsystemsanalysis,ratherthanbeingobjective,wasinfact subjective being ‘customised’ by the civilians surrounding theSecretaryofDefensetobothjustifyandsupportdecisionsthatMcNamarahad alreadymade. AccordinglyMcNamara applied these concepts to theXB-70programme–andtoGeneralCurtissLeMay.

According to Special Counsel Ted Sorensen, Kennedy regardedMcNamaraasthe‘...starofhisteam,callinguponhimforadviceonawiderangeofissuesbeyondnationalsecurity,includingbusinessandeconomicmatters’.

Initially,thebasicpoliciesoutlinedbyPresidentKennedyinamessagetoCongressonMarch28,1961,guidedMcNamarainthereorientationofthedefenceprogramme.Kennedyrejectedtheconceptoffirst-strikeattackandemphasized theneedforadequatestrategicarmsanddefence todeternuclearattackontheUnitedStatesanditsallies.USarms,hemaintained,must constantly be under civilian command and control, and the nation’sdefenceposturehadtobe‘...designedtoreducethedangerofirrationalorunpremeditatedgeneralwar’.TheprimarymissionofUSoverseasforces,incooperationwithallies,was‘...topreventthesteadyerosionoftheFreeWorld through limited wars’. Kennedy and McNamara rejected massiveretaliation for a posture of flexible response. The United States wantedchoices in an emergency other than ‘... inglorious retreat or unlimitedretaliation’, as thePresidentput it.Outof amajor reviewof themilitarychallenges confronting the United States initiated byMcNamara in 1961cameadecisiontoincreasethenation’s‘limitedwarfare’capabilities.Thesemoves were significant because McNamara was abandoning PresidentDwightDEisenhower’spolicyofmassiveretaliationinfavourofaflexibleresponse strategy that reliedon increasedUScapacity toconduct limited,non-nuclearwarfare.

Anotherofthe‘newregime’waseconomistAlainEnthoven.HewasaDeputyAssistantSecretaryofDefensefrom1961to1965,andfrom1965to1969hewastheAssistantSecretaryofDefensefor

SystemsAnalysis.

Followingtheguidanceofhisrationalistbrethrenat theRANDCorp.,the famed think tank brimming with mathematicians and game theorists,McNamara found an alternative in the doctrine of counterforce, wherebytheUnitedStateswouldtrytolimitanuclearexchangebyinitiallytargetingonlyenemymilitaryforces.TheideawastoholdSovietcitieshostagetoafollow-onstrikeinanattempttocontrolescalationandpreventretaliation.

On30June1961,PresidentKennedysworeinGeneralCurtisLeMayasChiefofStaff,USAirForce.Hesaidinhisspeech:‘Iwanttoexpressourgreatpleasureat theassumptionof this responsibilitybyGeneralLeMay.HewasoneofthemostdistinguishedcombatcommandersinWorldWarII.HeplayedamostinstrumentalroleindevelopingSACintoitspresenthighpeakasthegreatshieldoftheUnitedStatesinthefreeworld.

HebringstotheresponsibilitiesoftheChiefofStafflongexperienceinthe Air Force, and also a wide recognition of the challenges andresponsibilitiesandopportunitieswhich face theUnitedStates inmeetingourcommitmentsaroundtheglobe.

It’sasourceofsatisfactiontomepersonallyasPresident,tobeabletorelyonhiscounselasamemberofagroupofdistinguishedAmericans,theJoint Chiefs of Staff; and I think the fact that so many Members of theCongressareherefrombothpartiesindicatesthewiderespectwhichhehasinthecountry.

So, General, we want to say that, speaking personally, and also asPresident,thatit’sagreatpleasuretowelcomeyouasthenewChiefofStaffoftheUnitedStatesAirForceandmemberoftheJointChiefsofStaff.’

AsAirForcechiefofstaff,LeMayclashedrepeatedlywithMcNamara,

AirForceSecretaryEugeneZuckert,andthechairmanof theJointChiefsofStaff,ArmyGeneralMaxwellTaylor.Atthetime,budgetconstraintsandsuccessive nuclear war fighting strategies had left the armed forces in astate of flux. Each of the armed forces had gradually jettisoned realisticappraisals of future conflicts in favour of developing its own separatenuclearandnon-nuclearcapabilities.Attheheightofthisstruggle,theUSArmy had even reorganized its combat divisions to fight land wars onirradiated nuclear battlefields, developing short-range atomic cannon andmortars in order to win appropriations. The United States Navy in turnproposeddeliveringstrategicnuclearweaponsfromsuper-carriersintendedto sail into range of the Soviet air defence forces. Of all these variousschemes, only LeMay’s command structure of SAC survived completereorganizationinthechangingrealityofpostwarconflicts.

General LeMay sharedWhite’s contempt for the whizz kids and forMcNamara. He believed the civilians had usurped the proper role andexpertise of themilitary. In LeMay’s analogy,McNamarawas a recklessamateurwho ran theDefenseDepartment like ‘...a hospital administratorwhotriedtopracticebrainsurgery’.ExasperatedbyMcNamara’sirongriponAirForceprogrammes,LeMaywouldask friends: ‘...would thingsbemuchworseifKhrushchevwereSecretaryofDefense?’

Moreseriously,LeMay’sevaluationofSecretaryMcNamaraashavinga ‘...bombastic confidence’ in the ability of theUnited States to retaliateeffectively with ICBMs. McNamara had a growing reputation for hisreliance on statistics and little else. If there existed a concept, or even apieceofhardware,thathecouldnotreducetonumbersorachart,therewasagoodchance thathewouldquestion itsvalue.TheB-70wasacomplexaircraftandtheprogrammeforitsdevelopmentwaslikewisecomplexandexpensive.

McNamara disliked theB-70 programme because of this.Despite hislaterclaimstothecontrary,thereissolidevidencethathewouldnotacceptany testimony about the aircraft’s potential as a long-range bomber. HeevenclaimedthattheB-70couldnotbeusedtodropconventionalbombsbutcouldonlylaunchshort-rangeattackorcruisemissiles.Thissupposedlackofconventionalbombingpotentialof theaircraftwasusedasoneofhisreasonstodiscredittheB-70programme.

GeneralLeMayreachedthesummitofhisAirForcecareeronJune30,1961,whenhewassworninasChiefofStaffbySecretaryoftheAirForceEugeneMZuckert.ObservingtheceremonyintherosegardenoftheWhiteHousearethelatePresidentJohnFKennedyandthethenVicePresident,

LyndonBJohnson.

PresidentJohnFKennedyvisitingAtomicEnergyCommission-supportedLawrenceRadiationLaboratory(LRL)onMarch23,1963.PicturetakeninfrontofBuilding70AatLRLinBerkeley,California.Lefttoright:DrNorrisBradbury,DrJohnS.Foster,DrEdwinM.McMillan,GlennTSeaborg,PresidentJohnFKennedy,DrEdwardTeller,RobertMcNamara(SecretaryofDefense),andDrHaroldBrown(DirectorofDefenseResearchandEngineering).(TheLosAlamosNational

Laboratory)

YetMcNamarawanted to have theAirForceput thebombers on24-houralert,eventotheextentofhavingsomeofthemintheair24hoursa

day,justincasetherewouldbeanenemystrikethatwouldputthebombersinjeopardy.

AirForceofficerscouldnotmatchthewhizzkidsatusingtheiranalytictechniques. When Alain Enthoven testified before Congress, heoverwhelmedthegeneralswithchartsandgraphsshowingthat‘...theB-70wouldaddminimalextrafirepowerathugecost’.Still,themilitaryrejectedthenotion thatacomputer-generated ‘truth’providedbetteranswers thanthejudgmentandexperienceofmenwhohadactuallyfoughtawar.

General White, who had just retired as Air Force chief of staff,commentingaboutthosewhohadsetaboutsavagingtheB-70,programmesaid: ‘I amprofoundlyapprehensiveof thepipe-smoking, tree-full-of-owlstypeofso-calledprofessionaldefense intellectuals. Idon’tbelievea lotofthese often overconfident, sometimes arrogant young professors,mathematicians, and other theorists have sufficient worldliness ormotivationtostanduptothekindofenemyweface’.

TheTFXprojectThere was another reason for slashing the B-70 project. In the 1960s,defencecontractorswerealsocompetingforanaircraftcontractunder theTFX(TacticalFighter‘X’),orF-111programme.ThiswasajointNavyandAirForceprojecttodevelopafighterthatcouldbeusedbybothservices,ostensibly topreserve the ideaofeconomythroughcommonalitybetweenthem. The fact that the Navy really didn’t want the TFX made nodifference. In November 1962, the Department of Defense – that isMcNamara – decided that the TFX looked incredibly cost effective onpaper and that it would be produced by General Dynamics, FortWorth,Texas, of course, was – not so coincidentally – the home state of VicePresident Lyndon Johnson. The go-ahead for the F-111 program, andselectionofGeneralDynamicsas thecontractor,wouldbeapoliticalplusfortheKennedyadministration,andwouldbetheidealpaybacktotheVicePresidentforhisultimatesupportofKennedy’selectiontothepresidency–anothergoodreasonforittobesupportedbythePresident.TheselectionofGeneralDynamics as theTFXprimecontractorwas announcedat a rallyandabreakfastthatwasgivenattheTexasHotel,onthemorningofthedaythatKennedywouldbeassassinatedinDallas.

Money for the F-111 had to come from somewhere, and what betterplacetobeginlookingforitthantocutaprogrammetheadministrationdid

notlikeinthefirstplace?SoMcNamaracuttheB-70bomberprogrammeback to three experimental research XB-70s and laid down the lawgoverningbudgetsandbombers.Hewouldhavehiswaywiththemilitaryandhisway,hebelieved,woulddissuadeanyaggressor frommountingafirststrikeagainsttheUnitedStates.

Achangeinrequirements–theReconnaissance-StrikeB-70.The mission requirements for manned bomber aircraft were starting tochange at this time—and, for good reason.Russia, after shooting downFrancisGaryPowers’LockheedU-2on5May1960,hadeffectivelyprovedthatitcould‘hitaflyinthesky’,astheSovietPremierNikitaKhrushchevhadboasted.What ismore, theSovietUnionwascreating theMiG25, ahigh-altitudeMach3interceptor,specificallytoshootdowntheB-70.

TheheartofStrategicAirCommand,SAC’scommandandcontrolsystemlocateddeepbeneaththeirHeadquarters.SenioroperationspersonnelwereincontinuouscontactwithallSACmissileandbomberbasesandwithnationalcivilandmilitarycenters.TheSACcommanderinchiefcouldbecontactedwithinseconds.SAC’sfamous‘redtelephone’waslocatedonthecommunicationspanel,centre.Graphicandpictorialinformationwasshownviaprojectorsonthelargescreensatleft.

(USAF)

So,forthemostpart,high-speed,high-altitudebomberswerebecomingobsolete. This prompted theUSAF to take a closer look at its upcomingstand-off capabilitywith its B-52G/HMPB aircraft, and look toward thecreation of a totally newmanned bomber type of aircraft, specifying low

‘treetop’ level altitude andhigh subsonic speedpenetrationcharacteristicsinstead—specifically, an advanced manned bomber, but with similar B-52G/Htypemissionprofiles.Subsequently,in1961,theAirForceinitiateditsSLAB(SubsonicLowAltitudeBomber)study.

In its effort to revive theValkyrie programme, theUSAF created theReconnaissance-Strike B-70Weapon System Programme. To do this, theAirForcealteredtheB-70missionclassificationfromB-for-BombertoRS-for-Reconnaissance Strike, and thereby created the proposed RSB-70Valkyrie. The USAF proposed to field a fleet of 60 RSB-70 aircraft by1969,with another 150 aircraft to bedeliveredby1971–oneXRSB-70,210 production RSB-70s. As projected, the first 10 production aircraftwould be used as RDT&E (research, test, development and evaluation)aircraft,thenabsorbedlaterbyuserbombwings.

Initially three aircraft would be built. American referred to thesemachinesasAV–standingforAirVehicle–1,2,and3,orAV1,AV2andAV3.TheYB-70servicetestexample,orAV3,wastobecompletedwiththeinstallationofthefullB-70weaponsystemandwastohaveprovisionsfortheintendedoperationalfour-mancrew.

TheAir Force issued serial number 62-0001 toAV 1 (XB-70-1), 62-0207 to AV 2 (XB-70-2), and 62-0208 to AV 3 (YB-70). Overallprogrammecosthadrisento$1.3billion.

Somewheredownthelinetheaircraftdesignationchanged.CertainlyinSeptember1964editionofSkywriter,aNorthAmericanEmployeeReport,theywerestillcalling62-0001asthe‘XB-70’astheheadline,butoninthetext, they refer to the same aircraft as the XB-70A. A month earlier inAugust, theUSAF issued an InterimFlightManualwhich also called theaircrafttheXB-70A,whichisthedesignationIwillusefromhereonwhentalkingaboutthetwocompletedairvehicles.

ThegeneralarrangementoftheXB-70.(NAARockwell)

Some sources suggest that the third aircraft – 62-0208 – was to bedesignatedastheXB-70B,otherscalledittheYB-70A,whichisprobablymorelikelygiventhatitwasclosertotheactualoperationaldesign.

Itwasnotuntilaftertheentireprojectclosedandthesolesurvivorwasretired to amuseum– inApril 1972 – thatNorthAmerican revealed thedifferences with the three aircraft. According to NAA ...At the time ofprogramredirection to threeXB-70airvehicles (3-31-61), itwasplannedthatAV’s1and2wouldbeidenticalindesigntodemonstratethetechnicalfeasibilityofB-70typeaircraftdesignandAV3wouldincludeprovisionstodemonstrate the functional operation of a prototype bombing-navigationsystem’.

Subsequenttothisredirection,systemsdevelopmentandmanufacturingconsiderations led to furthersignificantdifferencesbetweenAV’s1and2,asfollows:1. AV 1 had zero degree wing dihedral versus 5 degree on AV 2. Thischange was issued to correct lateral dynamic stability problems atintermediate supersonic speed and became evident too late in themanufacturingprocesstobeincorporatedonAV1whichutilizedabobweighttoprovidethecapabilityforpilotcompensation.

2.Amanual air induction control systemwas utilized onAV1 versus anautomatic system on AV 2. An interim manual system with limitedautomatic features was flown on AV 1 due to development schedulesassociatedwiththeautomaticsystem.

ThegeneralarrangementoftheproposedRS-70.(NAARockwell)

3.Thewing-to-fuselagejointdesigndifferedbetweenAV’s1and2.Duetowing-to-fuselage mismatch problems encountered on AV 1, the joiningtransitionareawasredesignedtofacilitateassembly.

4. AV 2 had a 2800 gallon greater fuel capacity than AV 1. This fuelcapacity difference was primarily attributable to Tank No. 5 beingblockedoffonAV1duetoproblemsexperiencedinsealing.

It was planned that AV 3would be similar in structure as AV 2 but thatmodification would be made to include provisions for the bombing-navigationsystemasfollows:1. Four-man crew on AV 3 versus two-man crew on AV’s 1 and 2. Anobserver and system operator position were required in support ofbombing-navigationmissionsandsystemsoperations.

2.AV3requiredmajormodificationsintheenvironmentalcontrolsystem.Double versus single air cooling loops were required to support theadditional crewmen and electronic equipment on AV 3. In addition, agreatercoolingcapacityandaddedliquidcoolingloopswererequired.

3. Equipment bay variances Major electronic equipment additions wererequired insupportof thebombing-navigationsystemwhichresulted inrearrangement of the electronic and ECS equipment bays plus theblockingoffoftheNo.1fueltankforECSwater/icetank.

4. Nose cavity additions. The AV 3 bombing-navigation required theadditionofaninertialnavigationplatformandradarantennaequipmentwithassociatedcoolingloopsinthenosesection.

5.Secondary power system additions. An additional generator on engineNo. 5, line contactor, stepdown transformer, secondary bus and theassociated controls were required in support of the added electronicequipmentonAV3’.

Apairofartist’simpressionsofthecockpitoftheproposedB-70,thefirstshowingtheuseofwhatwerethen‘conventional’instruments...

In July 1963, the House Armed Services Committee, headed by CarlVinson,requested$491millionforthecompletionoftwoXB-70sandoneXRSB-70–thelatterbeingAV3,formerlytheYB-70,butmodifiedtotheRSB-70 configuration. Congress only allocated $52.9 million, totalling$275.9million,farshortoftherequiredamount.AsproposedfortheRSB-70programme,AV1wouldcontinueindevelopmentunaffectedandwouldproceedwithitsplannedfabricationandflighttestprogramme.

AV 2 would be modified to incorporate a dry in-flight refuelingreceptacle and its associated hydraulic fluid power actuation equipmentwithin the nose section forward of the VG windscreen on the aircraft’scentreline.Thismachinewould be retrofittedwith a new51° swept backleading edge on the canard foreplane instead of the 31° to evaluate theperformanceandflyingqualitiesoftherevisedsurfaceduringflight.Afterits initial flight test programme, a fixed missile launcher capable oflaunching two powered strike missiles, together with a missile coolingsystem,wouldbeincorporatedwithinAV2’saftweaponsbay.Equipmenttopower-open/closetheaftsegmentoftheweaponsbaydoorwasalsotobe

incorporated. This would allow the evaluation of launch and separationcharacteristicsoftheproposedstrikemissile.

AV3–whichwouldbetheXRSB-70prototypeandformerlytheYB-70servicetestairvehicle,wouldretainthebasicstructureofAV1andAV2 with the modification to employ the new higher sweep angle canardforeplane testedonAV2.A revised left-handvertical stabilizerwouldbeincorporated, with an isolation strip to house the proposed AN/ARC-90UHF(ultrahighfrequency)CommandCommunicationsystemantenna.

Provisionsfortheproposedfour-mancrewandapressurizedandcooledelectronicequipmentbayweretobeprovided,ashadbeenplannedfortheYB-70.Apower-operatedweaponsbaydoorwastobeprovidedfortheaftweapons bay. In addition, the structure in the lower portion of the #1forwardfuselagefueltankwastobemodifiedtopermittheinstallationofan 8-foot-long phased array antenna on either side of the air vehicle.Asplanned,thefirstproductionRSB-70wastoflyinearly1965,andAV13,orRSB-70number10,inearly1967.

...comparedtothevertical‘tape’instrumentsusedparticularlyfortheenginedisplays.InrealityaspectsofbothwereusedonAV.1andAV2(bothNAARockwell)

TheproposedRSB-70differedfromtheB-70inthatmultiple–upto20– guided air-launched missiles and associated reconnaissance equipmentwould be incorporated into the weapon system as a primary capabilityratherthanasanalternatemeansoftargetdestruction.Eachsegmentofthetwo-partweaponsbaywouldbeabletocarryten900-poundstrikemissiles

onapoweredrotary-typelauncher.SOR 82, which was revised on 28 February 1961, called for the

procurement of RSB-70 aircraft and specified that it be capable ofperforming missile strikes against heavily defended enemy strategic andmilitary targets, strategic bombardment (both nuclear and conventional),and strategic reconnaissance. The USAF/SAC Operational Plan (OP) fortheRSB-70,of15April1961,statedthattheaircraftwouldbecapableofcarryingdiversifiedweaponloadsofguidedandfree-fallordnanceandthatRSB-70 squadrons would operate from both primary operating andmaintenance bases and also from a large number of dispersed bases toreducevulnerability and reaction time. Itwenton to say that theRSB-70must have the ‘flexibility to respond effectively throughout the wholespectrumofpossibleconflict’.ButtheRSB-70programmedidnotgoforth.

During the construction of the third Valkyrie, the Air Force projectmanagers were fighting to save the programme. They had devised sevenalternate plans, each one trying to save something of AV 3, or for thatmatter, trying tosalvageeverythingpossibleof theentireprogramme.Allthe alternativeswere based on aminimalist proposal – building three airvehiclesandflyingtwoofthem.Theflighttestprogrammewastobejustextensiveenoughtoprovetherangeoftheenvelope,includingflightworkatMach3.

Anartist’simpressionofthedefensivestationatitwouldhaveappearedontheproductionB-70.Ithasbeenoft-statedthattheaircraftwouldcarryastate-of-the-artsuite–unfortunatelynooneseems

toknowwhatitwouldhavelookedlike!(NAARockwell)

Supporters hoped the programmes would provide a wealth ofinformation on high-performance vehicles, including data on speed,payload,altitude,anddurationofflightsathighspeed.TheSSTprogrammetesting,with funding fromNASA,wasabig sellingpoint forNASA, theAirForce,andcongressionalinterests.

Air Vehicle 3 – allocated tail number 62-0208 – was to be theevaluation aircraft for much of what was planned for the RSB-70. ThedesignforAV3wascompletedon31October1963.Manyofthetechnicalproblemshadalreadybeenworkedouton the first twoaircraft, includingmuchprogresson thecomplicatedbrazing techniques, the redesignof thehoneycomb panels for fabrication, and the elimination of assemblyproblems.

The procurement process for the raw materials was completed. Theaircraft required 24,452 square feet of honeycomb core PHI 5-7, sheetmetal quoted at 157,846 pounds, and 26,403 feet of linear extrusions.Fabrication processes on the subsystems and the subcontracted structurewereallonschedule.Thehoneycombpaneldesignwascomplete,withthe

fabrication of the honeycomb panels was still underway. By 24 January1964,theBombingandNavigationsystemsdevelopedbyIBM—andtheDoppler radar— had passed acceptance tests. Radar sighting equipmenthadpassedacceptancetestsatGeneralElectricandwasdeliveredontime.Integration tests at IBMwere all on schedule. The digital computer hadcompleteditsfunctionaltestwiththeDopplerradar.

Theoffensiveavionicssuitewasfurtheradvanced,withIBMcompletingtheASQ-28bomb-navsystemforAirVehicles2and3.TheIBMsystemhadbeentestedinafragmentarymannerona

varietyofsurrogateaircraft,butneverasacompletepackage.(NAARockwell)

TheproposedoffensivesystemsoftheB-70.Thisshowsasingle20megatonnuclearbombonboard

–howevertheaircraftcouldcarryavarietyofothernuclearandconventionalbombsaswellasmissiles.(NAARockwell)

AV3was to carry a four-man crew, two pilots and two observers, inwhat later would have been Bomb/Nav Officer and Defensive SystemsOfficer.The radomewas able to support 130 cubic feet of equipment for1,000poundsas star trackers, antennas, and soon.New requirements fortheequipmentbaybroughtchangesincreasinginsizefrom300cubicfeettoaccommodate12,000poundsofnewequipment.Theweaponsbaywasenlargedto1,200cubicfeetandcouldhold25,000poundsofordnance.Thestructural difference in the AV 3 was the lower fuselage, which waschanged to accommodate a new environmental control system and theassociatedductingandplumbingneededforafour-mancrewcompartmentandforcoolingtheelectronicequipment.

There was another interesting fact concerning the third Valkyrie.Becauseoftheshapeoftheengineinletducts,theValkyriewasconsideredto be a prime candidate for evaluating the performance of RAM (radarabsorbent material) coatings placed within the ducts. With the longenduranceandhigh-speedcruisecapacityoftheXB-70,designersfeltthatitwas particularlywell suited forRAM endurance and radar-suppressiontestflights.TestswereneededtomeasurethedetectabilityoftheXB-70andother large high-performance aircraft by radars and infrared seekers, bothwith and without suppression aids. Radar suppression would have beentested by placing theRAMmaterial in the air inlet ducts to diminish thereflectedradarenergy.InfraredsuppressionwastobetestedbycoatingtheXB-70 skinwithmaterial that could suppress infraredenergyat tacticallypivotalwavelengths.

Ground radarwas used in trying to determine the radar cross-section(RCS) differences in several radar frequency ranges. The informationgathered at different air intake duct ramp configurations determined theeffect of duct shape on the RCS. From this, researchers determined theeffectiveness and the durability of the RAM coating. The effect of thiscoatingonskintemperatureandstructuralintegritywouldbemeasuredbyonboardinstrumentation.

RCS was one of the tough selling points of the XB-70; on radar itlooked likeabarndoorcomingover thehorizon.AfterGaryPowerswasshotdowninhisU-2inMay1960,RCSbecameevenmoreimportant,witheveryeffortmadetomaketheXB-70looksmalleronradarscreens.

Indesperation,findotheruses!OnetaskdescriptionwrittenforValkyrieAV3citedplansforittobeusedasahigh-altitudeastro-observatory.That aircraftwouldbeequippedwithastronomical equipment and would fly to the best possible locations forobserving and recording astronomical events such as solar eclipses. Thejustificationexplainedthatthegreatertheflyingobservatory’svelocity,thelonger an eclipse could be viewed. At Mach 3.0, eight minutes wereavailableforviewingcomparedtofourminutesatMach1.0.Inadditiontolonger viewing times, the higher a flying observatory went, the lessatmosphericabsorptiontherewas,andcloudcoverwasnolongeranissue.TheXB-70wastheonlyhigh-performancevehiclethatwasstableenoughandcouldcarrythenecessarypayloadtosupportsuchaproject.

Despitethemeritsoftheproject,itwasnottakenup.TheUSApursuedlargerobservatoriesontheground.ItwasnotuntilthelaunchoftheHubbleSpaceTelescopeseveraldecades later that theUSAfinallygainedahigh-altitudeplatformfromwhichtoviewthestars.

Another ideawas to use theB-70 as a recoverable booster system tolaunch things into low earth orbit.Likely candidates included a proposedsatellite-interceptor and theAerospacePlane.TheDynaSoarprogram, thefirsteffortbytheUnitedStatestouseamannedboost-glidertoflyinnearorbital spaceand return,wasalsoconsidered in thiscontext inNovember1959. The B-70 was to carry the 10,000-pound DynaSoar glider and a40,000-pound liquid rocketbooster to70,000 feet and release themwhiletraveling atMach 3.The booster could then push the glider into its final300-mileorbit.

ThecapacityofAV3ifithadbeencompleted,showingtheweaponsbay,theequipmentbayandthenosebayforradar,star-trackersetc.(NAARockwell)

Therewere technicalproblems toovercome.Aweight issuehad tobewrestled with, since the B-70 would have been overweight in order toaccomplishthelaunch.ItwasthefirsttimethattheAirForcetriedtomergemissile,space,andaeronauticalsciencesintoonepackage,somanyissuesofcommunicationandcompatibilityhadtobeaddressed.

Had the system been completed, it would have had the capability tocarry its payload anywhere for launch and positioning—a useful featurewhen bad weather threatened a conventional launch schedule. With thespace shuttle system, a launch must be delayed if the weather over thelaunchpadorinanemergencyrecoveryareaisnotfavourable,resultinginthelossofhoursordays.

Therewas also a scheme to use the B-70 as a satellite killer to bothinspect and intercept enemy satellites in orbit. The B-70 would carrymissiles or drones to the upper atmosphere for launch against orbitingtargets.

In the late1950s theB-70wasauniqueairframe,whichpresentedanopportunity toexplorestaticandfatigueproblemsandextremelycomplexloadingof the aircraft. Itwashoped that these testswould lead todesignanswers concerning the Advanced Manned Penetrating Strategic System(AMPSS)andtheSSTasisdescribedindetailinalaterchapter.Staticandfatigue testingwould have scrutinized the forward fuselage,wing panels,horizontalstabilizer,andthelandinggear.

Testing would also evaluate the closed-loop engine inlet shock wavecontrols to monitor unstart conditions. The aim was to limit the violentbuffeting of the aircraft that resulted from the loss of shock wavepositioning in the engine inlet. This test would allow evaluation of inletcontrolsignalsthatcouldprovidetheinformationneededtorecordinletaircurrents. Ambitious as it sounded, the information from this test woulddeveloptheSSTandAMPSSinletcontrolandpropulsionsystemandhelplimittheeffectsofjetwashorturbulencecausedbyonesupersonicaircraftpassinganother.

Theproposedpropulsiontestingandin-flight‘spacesimulation’packageforthethirdvalkyrie.(USAF)

Planswerealsomadeforarecoverableboostersystemthatwouldpermitairlaunchesfromthebestpossiblepositiontoattainlow-earthorbit.(USAF)

ThedangerfromSAMstohigh-flyingaircraftwasdemonstratedbytheU-2incidentinvolvingFrancisGaryPowers–thisalsohadimplicationsforthe B-70. When an Air Force General suggested to the head of NorthAmerican Aviation, James H ‘Dutch’ Kindelberger, that the B-70s high-altitudemissionwas toodangerousdue to theSAM threat, hedecided toinvestigatelow-altitudepenetration.Thepurposeoftheinvestigationwastosee if thepilot and theaircraft could respond to theenvironmentofnear-supersonicspeedat lowaltitudeinenemyterritory.Testpilotsweretofly

the B-70 at Mach .95 at sea level and evaluate the effect of speed andclearance attitudes, predict the ability to avoid terrain, and detect grounddefence sites. The justification for it all was to recommend low-levelcapabilityforaB-70typeofdesign.Ultimately,similarhighspeedmissionswereflownyearslaterbytheRockwellB-1BLancer.

Another programme was to help estimate the defence of the UnitedStates and to provide information for the improvement of air defencesystems.Withnewantennasandothercountermeasuresystemsinstalledinthe bomb bay, themilitarywas to test and evaluate US defence systemsagainst threats, including manned enemy penetrators. The large payloadcapacity of the B-70 was to allow for many different types ofcountermeasure systems to be tested from subsonic to Mach 3 at highaltitudes.Itwashopedthatoneaircraftwouldbeable tosimulateeachofthe different manned penetrators that were considered to be potentialthreats.

Performance of communications equipment when working at highaltitudeandhighspeedwasalsoconsideredforstudy.ThetestswouldusetheXB-70sAN/ARC-50UHFsetandtheAN/ARN-65TACAN(withtheadditionofapoweramplifier)toshowtheincreasedcommunicationrangeaffordedby thehighaltitude.The testswouldaidSSTaswellasmilitaryresearch. Testing would also encompass evaluation of supersonic staticdischarge—acriticalfactorincommunicationsnoisereduction.Thetestsweretobedoneintwophases:PartItomeasureandrecordfieldstrengthsanddischargecurrents,andPartIItodeterminethestaticdischargedevice’sfieldlife.

Aircraft panel response to flutter and dynamic pressures fromoutsidedisturbanceswasanaeronautical issueatanyspeed.In theworldofhigh-speed flight and the threat of unstarts, it was of grave concern.Instrumentation was to be provided to measure the effects that occurredfrom acoustical forces. Noise-measuring instruments, includingmicrophones,transducers,andeventhermocouples,weretobemountedinhigh-noise-level areas such as the aft fuselage and the engine inlets.Thistestwould not require any excess flight time andwas to be done duringnormalflightprocedures.

A crew protection and environment study was to evaluate the crewundervariouscircumstancesand tolerance levels todetermine the typeofprotection required. Environment was the heading under which

temperature, pressure, air composition, and workload were measured.Radiationlevelsintheupperatmospherewerealsoaconcern.

High-speedandaltitudeoperation,fuselageflexibility,airvehiclesize,landing attitude and speed, and extended temperature and pressureenvironmentswereallissuesneedingexploration.Adaptivecontrolsystemswere beneficial to the evaluation of the AMPSS and SST, the automaticlanding systems, and the emergency descent capsule used for in-flightemergencies.

Weaponsandcomponents testing researchwas to aid in thedesignofnew ordnance, missiles, and components for use in supersonic aircraft.Environmentaldatawouldbegainedfortheeffectsofaerodynamicheating,vibration,acoustics,andGload.Instrumentationwouldprovideforweaponejectionshock,safeseparation,andtrajectory.Thetestswouldalsoprovideinformation pertaining to in-flight platform alignment of inertial-guidedmissiles, missile delivery accuracy, and ballistic determination ofsupersonicgravity-droppedordnance.SincetheXB-70wastheonlyaircraftcapable of performing in this high-speed, high-altitude theatre, itsnavigationsystemwasuniqueinthatitcouldprovideweaponsreleasedataforadvancedweaponssystems.

Exhibit20intheB-70FinalReport–theOver-NoseVisionMockup.(NAARockwell)

TheB-70mock-upseenfromadifferentanglethatshowsatthistimetherewasadistinct‘join’linebetweenthefrontfuselageandthemainbodythatwasblendedawaybythetimetheaircraftwas

actuallybuilt.(NAARockwell)

TheB-70wastobeusedtostudytheeffectsofhighaltitudeandhighspeed on navigation performance, including Stellar-Doppler inertial,Doppler inertial, pure Doppler, and pure inertial radars. The ability of aDopplerradartolockontoausablegroundreturnsignalathighspeedandhigh altitudes needed to be determined. The designers also planned toevaluatethestellarmonitorwhich,ifitweretobeusedinanyhigh-speed,high-altituderegime,neededtofunctionproperly.TheXB-70couldcreateashockwavesevereenough toaffect refractionof lightgoing to thestellarmonitor.TheXB-70wastheonlyaircraftthatcouldflythisregimethatwasalreadyequippedwithStellar-Dopplerinertialnavigationsystem.

Supersonic refueling was to precipitate the need for refueling high-speed aircraft.The studywould determine the feasibility and develop thetechnique for fuel transferat supersonic speed.Testvehiclemodificationsweretobebasedontheresultsofwindtunnel,flightsimulator,andflighttestsandwouldconsistofa‘dryhookup’betweentheXB-70andanothersupersonicaircraft(perhapsanotherB-70),simulatingatanker.

Another possibility under consideration was to turn the B-70 into anuclear-poweredaircraft.UnderaUSAFcontractNorthAmericanmadeaspecialdesignstudyofapossiblenuclear-poweredversionthatwouldgiveabomberwithalmostunlimited rangeandendurance. Itcouldmaintainalong-duration standing patrol carrying Air-Launched Ballistic Missiles(ALBMs), could approach, an enemy target from any direction withoutaerialrefuellingandcouldlaunchanattackatanyspeedfromMach0.9atsealeveltoMach3ataltitude.

Possible roles, in addition to strategic bombing, would have beenantisubmarine patrol and attack; early detection of hostile aircraft;interception of attacking forces at great distances from the US; ballistic

missile early warning and use as a launching platform for anti-ICBMmissiles; airborne mobile command post; and use for rapid deploymentoverseasforactioninlimitedwars.

It was thought that several features of the B-70 made it suitable foroperationwithnuclearpower. Its large sizewasconsideredanadvantage,becauseoftheweightofthereactorandcrewshielding.Thelongdistancebetween the crew and the power plantwould helpminimize radiation. Italsoappeared thatmuchof theaircraft’sbasic structurecouldbe retainedwithoutsignificantchanges.

TheproposedB-70RBS(RecoverableBoostSystem)withaDyna-Soarstylespacevehicleenclosedinabulgedbelly.(NAARockwell)

OtherViews–OtherImplicationsIn an in-depth interview given on 9May 1964,Director ofDefence andResearch Engineering Harold Brown revealed much about the XB-70programme, along with a great number of insights into how one ofMcNamara’s ‘whizz-kid’ disciples saw the Air Force’s lobbying and theRSB-70:

‘The Air Force has been the glamour service, and I think this hasimpressed many congressmen. But this is outside of my field. I am justexpressinganonexpertopinion. I think theAirForcehasdevotedagooddealofefforttogainingthissupport.Ithasalonghistoryofdoingit.Ithasalways been more willing to go over the heads of its legally constitutedsuperiorstotheCongress.IthinkthatprobablycomesfromthefactthattheAirForceisalessrestrainedservice.Itisyoungerasaservice.Thepeople

in it, senior people in it have seen it emerge to a position of equality ordominance for a period there, from being part of another service, frombeingpartoftheArmy.Intheperiodofthe’30sand’40stheyfoughthardtogiveitautonomy,subsequentlytogiveitindependence,andafterthattogiveitdominance,andtheysucceeded.

Ofcourse,thependulumhasswungbackawaysnow,butthishistoryofincreasing prominence and success, and less tradition, or youngertradition,IthinkhasmadeseniorAirForceofficersmorewillingto,orlesswillingtobeboundbydecisionsofciviliansuperiors.

Itisgoingonrightnow.Ithasbeengoingonforyears.GeneralLeMay,whenthedecisionwentagainsttheB-70,orwhentheSecretaryofDefensedeclined toapprove$50million in the1965budget foradvancedmannedpenetrating system development, didn’t hesitate to send people up to theHill,AirForcepeopleuptoCapitolHill,tolobbyagainstthosedecisions,andgotCongressatonepointtodirectmoneytobespentontheso-calledRS-70system.Hewasdoingwhathethoughtwasright,andIthinkthereisjustnoquestionthatheislegallyentitledtodoso.

TheB-70wasaprogramwhichhadhaditsupsanddowns.Ithadmoreorlessbeendecidedagainstin1959,andagainin1960ithadbeencutwayback. In fact, it had been effectively reduced to component development.Then in the fall of 1960, during the presidential campaign, a tentativedecision was made and announced to reinstitute a program, but withoutmakingadecisionfordeployment.Thedecisionwasannouncedtogobacktoasubstantialdevelopmentprogram.

Themoneyforthatwasneverreleased,soinJanuaryandFebruaryof1961,thenewadministration–thiswasbeforeIarrived–wasfacedwithadecisionastowhattodo.Thedecisionthatwasmadeatthattimewastohaveathreeaircraftprototypeprogramwithnodeployment,noproduction.Itwasbelievedthreeaircraftprototypeprogramcouldbecarriedoutwithatotalcostof$1.3billion.

This is theXB-70.XBmeansexperimentalbomber.ThatXmeans justan experimental aircraft, not a production item.Most of that $1.3 billionhad already been spent, but of that five or six hundred million dollarsremained. This was the way things went along until – well, this was thedecision. Things went along that way until the following spring for therevisedKennedy-Eisenhowerbudget.

That fall the corresponding budget was put in for the XB-70, but in

Octoberof1961, theAirForcebasedonsomesuggestions thatpeople inmy own office hadmade to them, started to look atwhat they called thereconnaissance strike concept, butweasked them to thinkaboutwhat anaircraft could do that a missile could not do, and come up with someanswerstothatquestion.Theydidthinkaboutit,andtheycameupwithabriefinginOctoberof1961,onwhattheythencalledtheRS-70,whichwasdifferent in idea from the B-70. The B-70 had just been a conventionalbomber with one or two or three great big bombs in it which would becarriedovertoapredeterminedtargetanddroppedonit.

The idea of the RS-70 was to put in many smaller bombs, missilelaunched,actually,soas togiveonebettereffectiveness for thesystem. Itdoesn’t really takea50megatonbomb toputmostmilitary targetsoutofcommission. This would allow you to attack many targets. It also addedsuch concepts as a side-looking radar to give you good resolution, goodbombingaccuracy,sothatyoumightbeabletogetbywithverysmallyield,verysmallnuclearyield,andalsosomeotherconceptswhichwerereallyjustideas.

AnotherproposalwastouseaB-70asalaunchvehicleforsomethinglikeanX-15,withadockingbayfittedontotheB-70’sspinetogetthesmallcraftaloft.(NAARockwell)

After impact, you could see whether the crater that you had leftincludedthetarget.Ithinkthathadacertain–toadegreethatprobablyistrue.

There was this enormous collection of claims for the aircraft,supportable,dubious,andridiculous,whichgraduallyevolvedbetweenthetimethefirstpresentationwasmadetotheSecretaryofDefenseinOctober,andthetimeatwhichitwaspresentedtoCongress,actuallytotheHouse

Armed Services Committee, on the House Armed Services committee’srequest,aftersomeone in theAirForcehadinformedthemthat therewassuchabriefing.

Theywentupandtheypresentedthis.Thecommitteedecidedthatthispresentationwasworth$300million,andput thatmoneyin thebill.Theyput it in originally directing it be spent, which did lead to a fairly nastyexecutivelegislative conflict of ‘can the legislative direct that money bespentforsomethingeveniftheexecutivedoesnotwanttospenditforthat?’

Even though this was research and development money, and if Iremember correctly there was no authorization for research anddevelopment required at that time, theHouse Armed Services Committeeput into theauthorizationbill themoneyandthedirectionthat itbeused.TheSenatewentalongandthebillpassed,althoughtheSenatedidchangethewordingfromdirectingSecretaryoftheAirForcetospendthemoney,to languagewhich removed the attack on executive prerogative.But thenthe money had to be appropriated after having been authorized. That iswhen I spent my time with the House Defense AppropriationsSubcommittee.Theyappropriatedonly$52millionofthethreehundredandsome odd million which was authorized, on the basis that theinstrumentationrequiredhadnotbeendeveloped.Therewasnoproofthatitcouldbedeveloped.Thismoneywastohelpdevelopit.

Interestingenough,afterthemoneyhadbeenappropriatedforthis,theAir Force, since it was clear there was not going to be a big RS- 70program,gotverymuchlessinterestedinthequestionofwhetheranyofthethingswhichtheyhadsaidtheycoulddoandwoulddoasfarastheRS-70werefeasible,andsoIthinkalthoughthatmoneyhasbeenused,ithasbeenincorporated into theXB-70programto try toget theairplane to fly,andverylittleofitintheendhasbeenusedfordevelopingside-lookingradarofthisresolution.

Brownwasaskedif theXB-70programmehadbeencontinuedall thetime-

‘That is right. It has stayed the Defense Department-Administrativeprogram.Ithasrequiredintheend$200millionofadditionalfunding,andtheprogramhasbeenreducedtotwoaircraft,fromthree.Thefirstaircraftisayearandahalflate.ItwassupposedtoflyinDecemberof1962.Itwillprobably fly this summer.But thebigquestionwasnever reallyabout theaerodynamic capabilities—that is to say, whether you can fly a Mach 3

aircraft. It was whether the crew of a manned aircraft, whether theavionics,theside-lookingradar,thebombingsystem,thenavigationsystem,the air launched missiles could be accurate enough, resolution goodenough, and the crew quick enough at assimilating the information andtryingtofindunknowntargetstomakeasystemasuccess.

Thequestions are still unanswered, because as I say,when it becamecleartherewasnotgoingtobea$10billionRS-70program,theAirForcesuddenlygotverymuch less interested inanswering thequestions. I thinkthat they are going to come up again in connection with the advancedmannedpenetrationsystem.Butthewholequestionoftechnicalfeasibility,the human capability is still an unanswered one. There is an antecedentunanswered one which McNamara insists on having answered first, andwhichisreallytheveryfirstquestion,andthatis,whatisthatyouaregoingtodowiththisthatyoucan’tdobetteroraswellorcheaperinotherways?Thereisthedamageassessmentmission.Thereisthepreciseattackwhichisaveryaccurateattackmission.Thereisthemissionoffindingtargetsyoudidnotknowabout.Thereisthemissionoffindingmobiletargets.

AnotherplanforthethirdValkyriewasforanhigh-altitudeobservatorywhichwouldprovidebetteraccesstoastronomicphenomenathanagroundbasedobservatory.AirVehicle3wouldbeableto

‘chase’asolareclipseforexamplealongit’spathacrosstheearthratherthanrelyonasinglegroundbasedobservation.(USAF)

Onehastoweighalloftheseagainstthefollowingcriteria:cantheybedoneatall?Canyoudotheminotherways?Howexpensiveisittodotheminotherways?Howimportant is it todo them?Until thosequestionsare

answered, any such program is unlikely to be approved for very largeexpenditures.

The interviewer then questioned Brown if it was his office that hadpushedtheAirForceintogeneratingtheconcept,butthathe–Brown–hadneverbeensatisfiedwiththeirdefenceof...

I think that is accurate as an appraisal of the situation.Wewere theonesthatsaidtothem,‘Youhavetofindsomethingthattheaircraftcando– the only justification for manned bombers, aside from diversity of theforce,whichissomejustification,butnotmuch,istofindthingsthatitcando thatmissilescan’tdo’.They tookoff fromthatpoint to try tocomeupwiththeanswers.Idon’tthinktheyhavecomeupwithacceptableanswersyet,butIthinkthattheyshouldkeeptrying.

The interviewer then asked Brown had he explicitly decided againsttheirdroppingbigbombs?

‘No, I think that is a separate question. I think that they decided ifdroppingbigbombsonpredesignatedtargetswasthegame,thatairplaneswere not necessarily the best way to do that’. Clearly, thiswas a simpleexpressionofpreferencetoICBMs.

The interviewer asked what was the President’s role in theseconsiderations,inparticularaboutwhatbecameknownastheRoseGardenincident – thiswas the infamous deal betweenSenatorCarlVinson, thenheadof theHouseArmedServicesCommittee,andaB-70supporter,andPresidentKennedy,madeintheWhiteHouseRoseGarden.

McNamarahadrefusedtospendfundsassignedtotheB-70programmeby using an obscure power created in a 1958 change in the NationalSecurity Act. So much was Kennedy enamoured of his Secretary ofDefensethatheworkedoutadealwithVinsonsothatCongresswouldletMcNamara have hisway. Itwas known thatMcNamara did not have thepolitical savvy toworkoutasituation in thenormalWashingtonstyle, sothe President, using his political skills with Vinson, had helped. Brownexplained:

‘Well, therewas the famousRoseGarden sessionwithCarlVinson inwhich President Kennedy is alleged to agreed with Mr. Vinson that hewould spendof theorderof$50millionon theprogram, thus savingonesixth ofMr. Vinson’s face, and Vinson had put in $300million dollars, Iguess.Inreturn,Vinsonagreedtowithdrawortorecedefromthelanguagewhichhehadput intohisbill,whichdirected theadministration tospend

themoney.TheSenate tookout the language in theirversionof theauthorization

bill, and it went to conference. The Senate included the money in theauthorizationbutwithdifferentlanguage.

ItseemsthatMcNamarareactedtoeventslikeanon-offswitch.Itwasallornothing.Thatkindofattitudedidn’tcutitwithCongress,theepitomeof compromise.Figuresdidn’t lie,McNamarabelieved;buthe alsoknewthat figures could be manipulated to prove anything. He had, at least,learnedthebasics.TheinterviewerthenturnedtothesnipingthathadbeinggoingononCapitolHill..

Oh, therearea lot of congressmenwhoare stillmad that theB-70–well,thereareveryfewcongressmenwhowillstandupfortheB-70,butforthewrongreason,becauseithasnotflown,andtheprogramisobviouslyalemon.That isnot reallyquite fair.The issue is thesameas itwas.Whatgoodisthemannedaircraft,andtheissueneverwascanamannedMach3aircraftfly,althoughasitturnsoutnow,thatisnotthebestplatformtouse.TheAirForceinthinkingaboutnewmannedbombersnowisnotthinkingofMach 3 high-flying aircraft. They are thinking of probably a variablesweepaircraftthatcanflylowandbelessvulnerablethatway.

But the real issue is as it has been.One of the things that amannedaircraftcandobetterthanaballisticmissilesystemlaunchedfromtheU.S.orfromasubmarine,isitfeasibletodothesetechnically?Howmuchdoesit cost and is it worth it? Those remain the issues, but as I say mostcongressmenhavebecomedisillusionedwiththeB-70buttheyarestillformannedaircraft,andtothatextenttheargumentpersistsandwillcomeupagainnextyear.Itdidcomeupagainthisyearinconnectionwithadvancedmannedpenetratingsystem,andwillcomeupagainnextyearwhentheAirForceasksforquitealotofmoneytodothis,asIassumetheywill.

Ithinkithasleftquiteabitofbadfeelingbetweensomecongressmenand civilian officials of the Defense Department, probably the more sobecausethesecongressmen,manyofthemrecognizethattheoutcomeoftheB-70programhasmade them lookbad,even though ifyoupenetrateonelayerdeeperitisclearthattheargumentstheyhavemade—whiletheymaybewrong,theyarenotprovenwrongbythefactthattheB-70fabricationoftheaircrafthasbeenunsuccessful.

Itisnotsurprisingthatduetotheradicalnatureofthedesign,modelsoftheB-70spentagreatdealoftimeinvariouswindtunnels,likethisoneatNASA.(NASA)

The contractor really underestimated the fabrication problem, whichshows that programs can go off the track, badly for non-fundamentalreasons,butthatpushesthemoffthetrackjustasbadly.

TheCongress, as I say, containsmany people who are very unhappystill,principallymembersof theArmedServicesCommitteeof theHouse,and to a lesser extent some of the members of the Armed ServicesCommittee of the Senate. But I think the senators, well, Senator Russell[Richard B. Russell, Jr.] and Senator Symington, Senator Saltonstall[Leverett Saltonstall] don’t feel nearly so strong about that. I think theyrecognizethattherearesomefundamentalquestionsherethattheAirForcehasnotanswered.

TheAppropriationsCommittees,particularlytheHouseAppropriationsCommittee, although they feel asmany people feel that it is amistake torelyentirelyonmissiles,hasnotadoptedpersonalattitude.Theydonotfeel

thattheirpersonalhonorisinvolved.InevitablyIhavebecomethefocusofsomeof thecongressional feelingonsomeof these, since Ihavebeen theonethathasoftenbeenusedtodefendtheSecretaryofDefense’spositioninthismatter,whichIthinkisacompletelydefensibleposition.

Brown was then asked to be specific as to who was doing theattacking...

Oh,Iguesspeoplelike—notMr.Vinson,himself.Hehasalwaysbeenvery gentlemanly about this. ButFEdwardHébert, PorterHardy, Jr,MrRiverstosomedegree,WilliamGBray,LeslieCArends.Theissuealwayspresented isoneofmeversusGeneralLeMay.Theoutcome isapeculiarone.IthinkGeneralLeMayandIagreedonmanyofthequestions.Idon’tthink we — and many of the factors, and I think we disagree on theconclusions.ButbyandlargeIwouldbewillingtospendmoremoneyonthisthanI thinktheSecretaryofDefenseiswillingtospend,althoughfarless than General LeMay wants to spend. So General LeMay does notregardmeashisopponenthere.Ifanythingheregardsmeas,ifnotanally,atleastsomeonewhoissympathetic.

TheintervieweraskedBrownhisviewsoncontractorperformance...Idon’tthinkthereisageneralstatementthatonecanmake.Ithinkthat

there are a few good contractors, and that even the good ones fall downfairlyoften,andthatmostcontractorsfindithardbeingresponsible.Theydon’tliketotakeresponsibility.InthisIdon’tthinktheyareverydifferentfromgovernmentofficialsormilitarymenoranyoneelse.ButI thinkthatthe Bell Telephone Laboratories performance on the Nike Zeus wasoutstanding.Thereisnoquestionaboutit.Theyperformedaboutthattheysaidandaboutthetimetheysaidforaboutthepricetheysaid.Ithinkthatthe North American performance on the B-70 has been singularly poor.Theydidn’tthinkaboutitenoughbeforetheymadetheirpromises,andthentheydidn’ttakestrongenoughactionandtheygotintotrouble.

Itistooearlytotellhowwellitwillsucceed,butIthinkquitealotofworkhasbeendoneinincentivecontractinginresearchanddevelopment.Idon’t think it has produced the result it should because the research anddevelopmentcontractisonlyasmallpartofthetotalandacontractorcanstill buy in on the research and development contract, that is, underbid,evenifheknowsitisgoingtoleadtoapenalty,evenifheknowsitisgoingto lead to a zero fee, and expect to recoup on the production. But I dobelieve that such things as project definition, which force the contractor

andtheservicetothinkoutindetailwhattheproblemsaregoingtobeofthe development, how long the development should take, how much itshouldcost,forcethemtoproveoutthecomponenttechnologiesbeforetheygo into a big engineering or operating systems development, or showingsomesuccess.

This leads to thequestionofdidMcNamaraandhiswhizzkids reallyunderstandthetechnologybehindtheB-70andthedemandsitwasplacingonthosetryingtodevelopit?Afterall,theywerenumbersmen.Theysawthingsinblackandwhitetermsofstatisticalanalysis.TheintervieweraskedBrown if contractor performance evaluation was an innovation ofMcNamara’s?

Ithashappenedinthelastthreeyears,yes.Ithinkweweretheonesinthis officewhopushed it.Before you commit to a full scale development,you first go through a period of some months in which you detail thedevelopment in terms of cost, time, milestones, and so on, and assureyourselfthatthetechnologieshavedevelopedtothepointwheretheycanbeputtogetherinasystem.Youarriveatascheduleandcostandperformancefigureswhichcanbemadethebasisofanincentivecontract.ThiswaytheSecretaryofDefenseknowswhenhemakesadecisionwhatheismakingadecisionabout,thatis,itavoidsputtinghiminapositionofdecidingtogoahead with this $500 million project which then turns out to cost $1.5billion,andhadhebutknown,hewouldnothaveapprovedit.

Thedesignhadbeenfullyworkedover,themoneyallocated.Itwastimetoputpoliticsasideandcutmetal.

CONSTRUCTION

With its unique configuration, size, and power, the XB-70 was still anincrediblethingtoseeontheground,letaloneinflight.Fromtheforwardcanardstothemassiveverticaltwintails,itlookedlikeacobrajustwaitingtostrike.Itsappearancewaskinetic:peoplewhosawitparkedontheflightlinefeltasifitwasalreadymoving.

TheB-70wasbasicallyadeltawingaircraftwithcanards; theseaidedin counteracting the trimchanges thatwere intrinsic to flight at transonicspeeds. They increased stability at high angles of attack and allowed forchangestobemadewithoutaffectingtheperformanceofthedeltawing.

The canard trailing edges could be lowered up to 25 degrees, whichwouldforcethenoseup.Tocompensate,theelevonsmoveddown,causingallthesurfacestoliftwithnothingbeinglostfromthebasicwinglift.Thispermitted the B-70 to land at a conventional speed equivalent tocommercialjetaircraft.AlthoughcanardswereamainstayoftheB-70,incertainconfigurationstheycreatedunstableairflowaroundtheentrancestotheengineinlets.

Compression lift was designed into the B-70 with the wedge-shapedengineboxpositionedunder thewingof theaircraft.Thiscausedpositivestaticpressurebehindthemainshockwavetoreactonthelargeunderwingsurface.Sincethereisnoeffectontheairflowingoverthetopofthewingto cancel out the resulting lift, at least a 30% improvement in lift wasavailablewithoutanyincreaseddragontheaircraft.

Thefoldingwingtips–ifgiventheirsizetheycouldbecalled‘tips’–ofthe B-70 were another design innovation. They pivoted in flight so theycould be folded down for supersonic cruise. This configuration reducedsupersonicdirectionalstabilityproblems,allowedtheverticalstabilizerstobesmallerthantheymightotherwisehavebeen,anddecreasedtrimdragathighMachnumbers.Therewerethreepositionsforthewingtips:

1.Upatsubsonicspeed.2.25degreesdownforlow-altitudesupersonicflight.3.65degreesdownforhigh-altitudeMach3flight.

Lookinglikesomethingotherworldly,thefuselageofAV1startstocometogether.(NAA/USAF)

2February1962,andthetitaniumcockpitofAV1comestogether.Thefourescapehatchesareclearlyvisible.(NAA/USAF)

TheXB-70designhada long,gracefulnosethatsupportedamovablenose ramp that formedoneof twowindshields.Themoveablewindshieldand ramp assembly consisted of five full-tempered glass panels in aframeworkstructurehingedat theforwardendandguidedbyfour frame-mountedrollerassemblies.Inthefull-upposition,theslopeoftherampandwind-shieldformedanosesectioncontour thatprovidedminimaldrag. Inthe full-downposition,a24-degree slopeprovided increasedvisibility forlow-speedoperations.Intermediatepositionscouldbeselectedasnecessary.

The moveable windshield and ramp assembly was hydraulicallyoperated and electrically controlled. An emergency system was providedthatallowed the ramp tobe fully lowered if theprimary systemfailed.Awindshield anti-ice and rain removal system directed 600° F high-temperatureengineextractionairthroughtwonozzlesontheleadingedgeof the movable windshield. The inner fixed windshield consisted of fiveglass panels in a 78-inchwide, 200 pound 7Al-4Mo titanium forging. Adefoggingsystemwasprovidedfortheinnersurfaceofboththemoveableandfixedwindscreens.

The canard servedmainly as a trimmingdevice, but couldbeused inconjunctionwiththeelevonsforadditionalpitchcontrol.Theentirecanardcouldbedeflectedfromzerotosixdegreesfortrimcontrol,andthetrailingedgecouldbelowered20degreestofunctionasaflap.Leadingedgesweepwas31.7degreeswithatotalareaof265.28squarefeet(415.59squarefeetincludingthefuselageportion).Thecanardwasconstructedfromatorsionboxmade of corrugated titanium spars and skin panels. Its leading edgesweremadefromstainlesssteelhoneycombsandwich,andthetrailingedgeflapsweretitanium.

TheprojectedexternalskintemperaturesontheXB-70.(NorthAmericanRockwell)

High temperatures encountered when flying at Mach 2 to 3 made itnecessarytobuildtheXB-70outofsomethingotherthanstandardaircraftaluminium.

That ‘something’was stainless steel honeycomb. TheXB-70was notthe first aircraft to be designedwith stainless steel honeycomb sandwichpanels;theB-58Hustlerhaduseditinseveralplacesearlieron.However,

the XB-70 airframe consisted of at least 69% honeycomb material.Powerfulastheaircraftwas,weightwasanimportantconstraint.Sincethehoneycombmateriallentitselftolightweight,strength,smoothness,fatigueresistance, low heat transfer, and reliability at high temperature, it wasconsideredtheprimecandidatefortheB-70.

ThemakeupofthestainlesssteelhoneycombpanelconstructionusedoverlargeareasoftheXB-70.(NorthAmericanRockwell)

NorthAmericanengineersdesignedtheXB-70’sskinsothatinsteadofasinglelayer,itwasa‘three-thicknessskin’,incorporatingatwo-inchlayerofhoneycombfoilbetweentwothinsheetsofstainlesssteel.

ThestainlesssteelhoneycombwasexpensivetoproduceinsuchlargequantitiesaswouldberequiredbytheXB-70.Specialautoclaveshadtobebuilt so that the sheets couldbeheat-treated in larger sizes thanhadeverbeendonebefore.Thesheetshadtoberolledsothin,downtoalmosttwo-thousandths of an inch, to compensate for any additional weight gain.Brazingthesheetstogetherbroughtwithitproblemssocriticalthatworkershadtowearglovestopreventoilfromtheirfingertipsfrominterferingwiththe metals as they were joined together. After cooling, the sheets wereinspectedbyasonarbeamtodetectanyflaws.

This honeycomb material was used in the wings, engine box, mid-fuselage,andverticalstabilizers.ThestainlesssteelusedwasPHI5-7Mo.(molybdenum steel). Titanium was about 8% of the total dry weight of150,000pounds,usedmainlyintheforwardfuselage.Therewereactuallythree typess of titaniumused.The firstwasTitanium6Al-4V,whichwasheat-treatedandusedinthicknessesof0.030inchesto0.070inchesfortheforwardfuselageskinand60-footskinandstringers.Thesecondwas4Al-

3Mo-lV, heat-treated to 170,000 pounds/square inch. The third type oftitanium, 7Al-4Mo, was used and also heat-treated to 170,000pounds/squareinch.Inall,atotalof22,000titaniumpartswereusedintheXB-70with12,000intheforwardfuselagealone.Titaniumwasalsousedinthecanard’smainbox,flaps,andverticalstabilizers.

AsWayneAReinscheofNAAexplainedatthetimethebackgroundtothematerialandhowitbecameusedintheB-70:

Themajorsubassembliesoftheforwardfuselage.(NorthAmericanRockwell)

Alow-lighttimeexposureseemstosomehowmakethispictureoffittingtheextremenosesectionlookallthemoredramatic....

‘Titaniumprovideduswithanunusualopportunity toobserve, and toparticipateinthedevelopmentof,astructuralmetalfromitsinitialhaltingsteps of technical development to its position today as amaturematerial

withasolidrecordofaccomplishment,andthepromiseofaneverbrighterfuture.

A number of false starts and innumerable detail problems inevitablyarose.Theyranthespectrumfrompoorsurfacecondition,lackofflatness,andpoor thicknesscontrol, toalloysegregation,hydrogencontamination,andtheweldingofthematerialtocuttingtooledges.

Attesting to the satisfactory solution to these problems is theoutstanding service record achieved by titanium alloys over years ofmilitaryandcommercialapplicationsinairframesandengines.

The developments in titanium technology in the past 10 or 15 yearsprobably exceed the progressmade in aluminium or steel technology forany comparable time span. This point has been emphasized repeatedlywhen we have used aluminium and steel to make comparisons with ourtitanium data, only to find that similar data have never been obtained inthesemoreprosaicmaterials.

...afewdayslater,on6February,thecockpitsectionwasmatedwiththeotherforwardfuselagecomponents.(BothNAA/USAF)

ThefirststageofAVCOAerospaceStructuresprocessforfabricatingthestainlesssteelhoneycomb

structurewastocreateamastermodelinasimilarmannertohowDeHavilland’sofEnglandmadetheirDHMosquitobackin1940.Thismastermodelwasthenusedtocreatethecomplexshapes.

(ACVOCorp)

In 1955 a daring concept of an aircraft with the ability to carry apayloadintercontinentaldistanceswasviewedbymanyknowingtechnicalpeople as not feasible. A further study of the concept imbedded thisconviction more deeply in the minds of many, and kindled the spark ofinspirationinthemindsofafewwhohadthevisionandfaithtoproceed.

The XB-70 was characterized by a long forward fuselage – oftenreferredtoindocumentsasthe‘neck’–withacanardlocatedjustaftoftheflightdeck.Attouchdown,thepilotwas30feetabovethegroundand110feetaheadofthemainlandinggear.

The fuselage was a semi-monocoque structure of basically circularsection, changing to a flat-top section in the crewcompartment area.Theforward fuselage was made of riveted titanium frames and skin overlongeronsofH-11steelcommonlycalled‘toolsteel’byengineers.

Themaincrewentrancewasontheleftsideoftheaircraft,forwardofthecanard.Thisentrancewasseventeenfeetabovegroundlevel,requiringspecialaccessstandsforentryandexit.Carehadtobetakentoensuretheaccessstanddidnottouchthefuselage,sincerubbingcouldresultinminorsurfacedamagethatwouldbeaggravatedbyMach3flight.Therewerefourseparatehatchesintheupperfuselage,correspondingtothepositionsoftheexpected four-person crew in any future production version. In the XB-70As,thetwoforwardhatcheswereremovedbyexplosivesintheeventofcrew ejection; the two aft hatches could be ballistically or manuallyremovedforaircrewescapeduringgroundemergencies.

Theintermediateforwardfuselagesection–underconstructionbyAVCOAerospaceStructuresof

NashvilleTN.Afterfabricationandinspection,thepanelswerejoinedtogetherbyfusionwelding.(ACVOCorp)

IntheorytheXB-70Asprovideda‘shirtsleeve’environment,butinfacteveryflightover50,000feetwasconductedwiththecrewinpressuresuits.Thecrewcompartment temperature couldbe regulatedbetween42°Fand105°F,accordingtocrewpreferences.Aconstantpressurealtitudeof8,000feetwasmaintainedundernormalcircumstances,andanemergencyramairsystemcouldmaintainapressurealtitudeof40,000feet(requiringoxygen,butnotpressuresuits)intheeventofaprimarysystemfailure.

Wayne A Reinsche continues to explain the construction details: Theairframeof theXB-70contained12,000poundsofefficient titaniumalloystructure comprising 23,000 detail parts. The structure also contained22,000 square feet of stainless steel brazed honeycomb paneling; 22,000poundsofhigh-strengthH-11steel;andlesseramountsofRené41,Inconel718andotheralloys.

The selection of the proper materials for various sections of theairframewasapainstakingengineeringprocess, inwhich tentative targetpropertieswerefirstestablishedfortitaniumalloys,steels,andaluminiumalloys. Then, with the combined efforts of materials suppliers and NorthAmericanengineers,specificalloysandtypesofconstructionwereselected.

The airplane performance requirements dictated that aerodynamicheatingwouldproduce temperatures ranging from450°F to630°Fovermost of the aircraft, with higher temperatures in the engine areas. Therequirementforextremerangemeantthatthestructurewouldcontainlargevolumes of kerosene-like fuel. Previously used concepts for fuelcontainment had to be abandoned. Fuel bladders would have beenprohibitively heavy. Temperature fluctuations would make groove sealinginadequate. The concept of fuel-containing structure employing weldingand brazing was, therefore adopted. For purposes of reviewing thematerials selectionand the structural configuration,we can consider twocategories:fuel-containingandnon-fuel-containing.Inbothcategories,thehigh temperatures eliminated aluminium alloys as candidates, and thechoicelaybetweentitaniumalloysandhigh-strengthstainlesssteels.

Theassemblywastheninverted,andfittedwithstainlesssteelframesandbulkheads.TheentireunitwasthenshippedfromNashvilletoPalmdale.(ACVOCorp)

TheforwardfuselageofAV1arrivesoutsidethefinalassemblybuildingon31March1962.Thelowercut-outintheextremenosefortheattackradarsisverynoticeable.Theseradarswerenever

installedinthetwoaircraftthatwerecompleted.(NAA/USAF)

Fromastrength-to-weightratio,titaniumalloyswerethebetterchoice;however, in the fuel-containing areas, insulation became a controllingfactor. Itwas necessary to keep the fuel below 300°F, and this could beaccomplished by the use of honeycomb sandwich construction, with noadditionalinsulationorrefrigeration.

Brazedtitaniumhoneycombsandwichwasveryseriouslyconsideredfortheseareas,butwasabandonedbecauselittlewasknownaboutthebrazingoftitanium.Thefinalchoicewasbrazedstainlesssteelhoneycombformostofthefueledareas.

Intheforward60feetoffuselage,thedesignconditionsweredifferent.Here,honeycomb,evenwith insulation,wouldbe inadequate toprovideahabitable environment for the crewand for the electronic equipment, andrefrigeration would be necessary. Trade-off studies showed that, beingcommitted to refrigeration in this area, titanium skin and frameconstructionwouldbemoreefficientthansteelhoneycomb.

Thecentrefuselagearrivedatthefinalassemblybuildingon1April...(NAA/USAF)

Withthewealthofsuccessfulexperienceasabackground,thetitaniumapplications for the XB-70were approachedwith confidence.One of themaindesignparameterswas that theaircraft sustaina lifeof 5000 flighthours. This is a relatively short life requirement in comparison to therequirement of 40,000 or 50,000 hours for a commercial supersonictransport, and it meant that the fatigue life of the structure would bedeterminingfactors.

...andwassoonliftedintopositionontheassemblyjigs.

DetailsoftheencapsulatedseatasfittedtotheB-70.(NorthAmericanRockwell)

CrewCapsulesThe pilot and co-pilot sat side-by- side in individual escape capsules.OnAV 3 and operational aircraft there would have been offensive anddefensive systems operators sitting behind the two pilots. Each escapecapsule had a self-contained oxygen and pressurization system, affordingcompletecrewprotectionduringandfollowingejection.Thecapsulescouldalso be closed, if necessary, for crew protection during an in-flightemergency, particularly one that involved the decompression of the crewcompartment. Limited control of the aircraft and engines (throttle downonly)waspossiblefrominsidetheclosedcapsules,whichhadawindowon

thefrontedgesotheoccupantcouldseetheinstrumentpanel.Whenthecapsuleswereclosedthecrewmicrophoneswereconstantly

‘on’ to provide continuous communication. The capsules provided ameaningful method of escape from the B-70 from an altitude of zero to80,000feetandatspeedsfrom100to2,000mph.

TheB-70FinalStudyReportasdrawnupbyNorthAmericanRockwellprovidedmuchadditionalinformationaboutthegeneralarrangementoftheencapsulatedseats.(NorthAmericanRockwell)

The encapsulation and ejection process was controlled by handgripswithin the capsules.Raising thehandgrips automatically encapsulated thecrewman, while squeezing a trigger within the handgrip jettisoned theescape hatch in the roof and ejected the capsule. A rocket catapultmechanismpropelledthecapsulefromtheaircraftandclearoftheverticalstabilizers,whilestabilizationboomsdeployedtopreventthecapsulefromtumbling. As the capsule descended, barometrically-controlled actuatorsdeployed the recovery parachute and impact attenuator. The extendedstabilizationboomsprovidedthecapsulewithaself-rightingcharacteristicin the event ofwater landing, and the capsulewaswater tight and couldfloat for prolonged periods. Indeed, an Air Force volunteer survived 72hours afloat in a B-70 capsule in January 1960 during tests. Survivalequipmentconsistingofcoldweatherclothing,aliferaft,sustenancegear,signalingequipment,firstaidkit,andrationswasprovidedinfourseparatekits ineachcapsule,mountedon theupper left and rightwallsandunderthecapsulefloor.

Fromthedrawingboardtoreality–theopenandclosed‘escapecapsule’asfittedtotheB-70.(NAA/USAF)

The encapsulation seat system was heavily evaluated at the JointParachuteTestFacilityatElCentro,CA,undergoing52rateofdescentandstructuralintegritytestsfromApril toNovember1959.Thiswasfollowedbyfivecapsuledropsat130knotsfromaC-130andtwelveejectionsat200to 280 knots at an altitude of 40,000 feet from a B-47. A further twoejection testswerealsoperformedatspeedsbetweenMach0.8andMach1.6 at 38,000ft using a B-58. Rocket sled tests were accomplished atHurricaneMesa,UtahtestfacilityandEdwardsAFB.

In the laboratory pressure chamber, the capsule underwent tests to amaximum ‘altitude’ of 100,000 feet using dummy, simian and humanoccupants.Outofdoors, thecapsulewasdroppedfromacraneseventeentimesoverlandandwaterwitheitheradummyorhumanonboard.

The B-70 instrument panels were a mixture of traditional roundinstruments and the unique vertical ‘tape’ instruments that found brieffavourduringthe1960s.Theinstrumentswerecolourcodedandilluminatedby white light, as the traditional red cockpit lighting washes out colour.Critical flight instrumentswerevisible from inside the capsuleswhen thedoorswereclosed.

AV1withthemoveablewindshieldrampinstalled.Thetwinruddersarealsoinplaceandoneofthewingpanelsisbeingmovedintopositionfortrimmingtocontour...

FoldingWingsThewinghadanaspectratioof1.751:1,withameanchordof117.75feetat the root and 2.25 feet at the tip. The leading edgewas swept back at65.56degreesandthetotalareawas6,297.15squarefeet.Theentireupperandlowerwingsurfacewascoveredwithbrazedstainlesssteelhoneycombsandwichpanelswelded together.Leadingedgeswereattacheddirectly tothefrontspar.Thesparswereofthesine-wavewebbedtype.AV1hadnoanhedral, but the second aircraft featured 5 degrees of dihedral. Bothaircrafthadaslightaerodynamictwistontheouterpanelleadingedge.Thewing-to-fuselage joint was 80 feet long and both the inner and outerhoneycomb face sheets of the upper and lower wing surfaces had to be

welded together. The first step welded the inner edge of the honeycombusing a tungsten electrode inserted through a 0.125 inchgapbetween theouterfacesheets,whichwerethenjoinedwithafillerstripweldedwithanelectron-beamguntominimizeshrinkage.Inall,therewereoversixmilesofweldingduringcomponentassemblyandtwoandahalfmilesofweldingduring final assembly; several of these miles involved the edges of fueltanks.

...whichwasdoneusingaspecialrigwith‘skates’runningontracksasseenheretocompletethefinaltrim.(NAA/USAF)

Thetrimmingrigisinplacetocutthefinalfittingofthewinghinge.Alargenumberofthewingpanelsareyettobeinstalled.

Thewing-to-fuselagejoinsweredifferentbetweenAV1andAV2,asshowninthesedetailsketches(NorthAmericanRockwell)

TwoviewsofthefrontandrearofAV1withthewingtipinfully‘down’position.Theaircrafthadtobeputonverytalljackstopreventthewingtiphittingthefloor.(NorthAmericanRockwell)

Theouter40%spanofeachwingcouldbefoldeddownwardtoincreasedirectional stabilityduringhigh-speed flight.Each tipoccupiedabout500square feet of area andwas driven by sixCurtiss-Wright 32,000:1motorhinges housed under a black magnesium-thorium fairing. On productionaircraft the leading edge of the fairing would have housed an infraredsensor for the defensive avionics. The wing tips could be set to threepositions:UP,HALF(25degreesdownonAV1and30degreesonAV2),andDOWN (64.5 degrees onAV 1 and 69.5 degrees onAV 2). TheUPposition was used or landing, take-off, and subsonic flight, the HALFpositionwasusedforsupersonicflight,whiletheDOWNpositionwasusedat very high speeds (Mach 2.5 and up). Use of the folding wing tipseliminated the increased drag that would have resulted if larger verticalstabilizershadbeenusedinstead.Whenthetipswerefullydown,theshockwave theygenerated impingedon thebottomsurfaceof thewing, addingabout5%morelifttothecompressionliftalreadybeinggenerated.

Weight-on-wheelssensorspreventedthewingsfrombeingfoldedonthegroundsincethetipswouldimpactthegroundinthefulldownposition.An

emergencyup systemwasprovided in theevent the twoprimary systemsfailedtoreturnthewingstotheuppositionduringflight.

Atfirstthedesignfoldedtheouter20%ofeachwing–however,windtunnelmodelssoonindicated thatadditionalsurfaceareawasrequiredfordirectional stability, so the fold line was moved inboard to between thefourthandfifthelevon.Thisledtocomplicationssincetheoutertwoelevonsectionswouldbelocatedonthefoldingpartofeachwingtip.Awingfolddisengagesystemwasincorporatedthatautomaticallylockedtheoutertwoelevonsectionsoneachwingat theneutralpositionanddisengaged themfromfurthermovementuntilthewingswereunfolded.

Elevonsatthewingtrailingedgeweresegmentedintosixsectionsperside to reduce air load bending effects. Two hydraulic actuators poweredeachelevonsegment,whichcouldmove30%upordownfromthecentreline. Symmetricalmovement of the elevons provided basic pitch control;differentialmovementprovidedrollcontrol.

Above:Aclose-upwinghingemechanismbeforetheaerodynamicfairingcoveredit.

Right:Thedateis6June1964,andAV1undergoeswingfoldtestswiththewingtipinthemidposition.(BothNorthAmericanRockwell)

The XB-70As had a flight augmentation control system that usedelectrical signals inparallelwithmechanical linkagesbetween thecontrolcolumnsandhydraulically-actuatedflightcontrols.Theactualdeflectionofthe flight control panels was primarily by the mechanical linkage; theelectrical control provideda small degreeofdeflection for trimpurposes.Theaugmentationsystemalsoprovidedauto-dampingaboutallthreeaxes.

Theverticalstabilizershadaleadingedgesweepof51.76degreesand234squarefeetofarea.Interestingly,ifNorthAmericanhadnotoptedforthefoldingwingtips,theverticalstabilizerswouldhaveneeded468squarefeettoprovideequivalentdirectionalstability.Onlytheforwardloweredge(aboutathirdofthearea)wasfixed;therestofthesurfacewasusedasarudderdrivenbydualhydraulicactuators.Thehingelinewaslocatedat45degreesfromthevertical.Therudderscoulddeflect12degreeseithersideofcentre.

Thefixedsupportingbasewasamulti-spardesignwithhoneycombskinpanelsandwasattachedtothewingrootjunctionbymechanicalfasteners.The movable rudders were also multi-spar with brazed honeycomb skinpanels.Leadingandtrailingedgeswerefull-depthhoneycombwedges.

The aft fuselage was a hybrid structure consisting of a variety ofdifferent construction techniques and materials. During high speed flighttheexternalskintemperaturesofsomeareascouldreach600°F,whilethe

internaltemperaturescouldexceed900°Fintheaftfuselageduetoengineheat.

Sincetheenginesoccupiedmostofthelast26feetofthelowerfuselageandtheairintakesandweaponsbayoccupiedmostoftheforwardsection,North American could not use full-depth transverse framing. In order tocarry the wing bending loads across the fuselage, NAA used multipleshallow-depthcrossbeamstoformtheupperpartofthebox.Thesideandlowertransverseframessupportedtheengineaccessdoorsandwereusedtocomplete thebox.ThesparsweremachinedfromH-11andused titaniumwebs.Atthesideofthefuselage,thehoneycombsandwichwingstubwasjoinedtotheH-11frameswithhigh-strengthmechanicalfasteners.Theskincoveringthetopandsidesofthelowerfuselagewas6A1-4Vtitaniumalloyriveted in place. The engine compartment doors used 6A1-4V titaniumalloyskinsover4Al-3Mo-lVtitaniumframes.

Partoftheaftfuselagewasacomplexpieceofengineeringdesign.IthadtomountthesixJ93engines,bestiffenoughtoabsorbthemassiveaerodynamicloadsofthewingsflexinginflightand

alsoprovidespaceforlargedoorstogiveaccesstotheengines.(NAA/USAF)

TheoriginalB-70designincludedtwoweaponsbays.Whenitbecameclear that the high energy fuel programmewould notmaterialize and thenewbomberwouldhavetorelyonless-efficientJP6,theaftweaponsbaywas converted into additional fuel storage. As built, the 29-foot longweapons bay on theXB-70As extended from fuselage stationYF1356 toYF1704. The opening of the baywas seven feet above ground level andwas covered by two sets of doors operating on a single set of tracks, thelength of which permitted only one set of doors to be opened at a time.Movingbothdoorsaftopenedtheforwardfourteenfeetofthebay;moving

only theaftdooropened the rear fourteen feetof thebay.Thecentreonefootwasunusablesince thedoorsnevercleared thearea.ThisalsomeantthatweaponslongerthanaboutthirteenfeetcouldnotbecarriedbytheB-70.

In the closed position the leading edge of the forward doorwas heldtight against the step fairingof the fuselage by two interconnectedhooksthatengagedthefuselagestructure.Theaftdoorwaslockedtotheforwarddoorinanidenticalmanner.ItshouldbenotedthattheweaponsbaydoorsonAV1andAV2werenotpoweredandcouldnotbeopenedinflight.AV3 would have had powered doors, as well as suspension and releaseequipment in the rear portion of the weapons bay for a single type ofweaponfordemonstrationpurposes.

WayneReinsche talksagainabout theB-70structure–particularcarehadtobetakenwithhowtheywerehandledandtreated:‘Thesearchforthealloyswithmaximumstrength,adequatefracturetoughness,andmaximumstiffnessledtotheselectionofanumberofhighlyspecialisedmaterialsinsheet,barforgingandextrudedform.Thesealloyswereusedinthesolutiontreatedandagedcondition(STA)fornearlyallapplications.

For skinswhere high strength combinedwith high fracture toughnesswas needed, the 6A1-4V(STA) material was used. Where high strengthcoupledwithmaximumformabilitywasneeded,suchasinframes,theUAl-3Mo-lV(STA)materialwasused.

The fabrication processes used for the titanium areas of the XB-70includedmanynewdevelopments, anumberof establishedpractices, andsome modifications of existing processes to accommodate the solutiontreating and aging sequences and the attendant high strengths. Ofparticular interest were thermal processing, forming welding, chemicalmilling,andmachining.

AJ93engineisgivenatrialinstallationasafunctionalcheckon26July1962.Thesizeofthe‘sixpack’astheengineareabecameknownisveryevidenthere.Fromthephotographitispossibletosee

thatoneverticalfinhasbeeninstalled,alongwithatemporarystrut.(NAA/USAF)

The26feetlongby9feettallmajorassemblyfixtureforthecrewcompartmentsidepanelthatusedopticalalignmenttocheckaccuracyofbuild.Allthemajorsub-unitswerebuiltinthismannerand

thenassembledintolargerandlargerunits.(NorthAmericanRockwell)

Thethermalprocessingoftitaniumalloyscouldbeusedtostrengthen,to soften, to relieve forming or welding stresses, to recover compressiveyield strength lost by forming, or to impart special corrosion-resistantproperties.Thermalprocessingcanproduceundesirablecharacteristicsinthe alloys, as well. Foremost among these are surface contamination byoxygenandnitrogen,anddistortion.

Both contaminated surfaces and distortion from quenching were

consideredseriousproblemsifthisoperationweretobeperformedatNorthAmerican. Another choicewas the purchasing ofmaterial in the solutiontreated(ST)orsolutiontreatedandagedcondition(STA)fromthemill.Thelatter choice would require that the contaminated surface problem andquenchingdistortionwouldbetakencareofatthesupplier’smill.

Ithadtheobviousadvantagesthatmaterialwithcontaminatedsurfacesfromthemillwouldhavepredictablethicknesstolerancesand,ifchemicalprocessingwere used to remove the contaminated surfaces, the hydrogencontent,whichmightbeincreasedbypickling,couldbedeterminedpriortoshipment.Apenaltyforthischoicewouldbereducedformability.

It developed that the supplierswere able to remove contamination bybeltgrindingandpickling,andkeepthehydrogenlevelswithinacceptablelimits. By stretcher leveling and roller leveling, a flatness of 3% or lesscouldbemet.Thiswasmeasuredbydividingthedepthofawaveorbuckleby one-half the length of the wave, measured crown-to-crown. It wasdecidedthat thereducedformabilityofSTmaterialcomparedto thatofAmaterialwasacceptable,andthesheetmaterialforSTApartswasprocuredasSTorSTA.

Just as Lockheed were pushing against the boundaries of what wasknownwiththeconstructionoftheirhighlysecretRS/SR-71Blackbird,soNorthAmericanwerecomingupagainstsimilarobstacles.Theformingoftitaniumand itsalloyswasonceconsideredunpredictableanddifficultbythe aircraft industry. Prior to and during theXB-70 programme,workingthis metal broke new ground and developed into a series of procedurescapableofproducingclose-tolerancepartswithhighstructural integrityatan acceptable cost. The higher cost of titanium alloys was one of thereasonsforthedevelopmentofprecisionformingmethods,sincethescrapratesacceptable in the industryforaluminiumalloypartswere intolerableforsimilartitaniumalloyparts.Tobringtherejectionratestoanacceptablelevel, a systematic approach was made to categorize the alloycharacteristicswhichaffected forming to identify thematerialdefectsandvariations which could cause rejected parts, and to establish exactingformingproceduresandlimits.

Wayne Reinsche: Titanium alloys are somewhat notch-sensitive,requiringcarefulattention toremovalofburrs,edgenotches,andsurfacescratchesbeforebeingformed.Marksleftbybeltgrindingofsheetsurfaceshave, at times, been a problem and have required polishing prior to

forming.Two specific types of contamination can be detrimental to forming

operationsandserviceperformance.One is formationofabrittle surfacelayerproducedbyheatingaboveabout900°Finthepresenceofair.Thiscontamination can be removed by blasting, pickling, or chemicalmilling.Theother typeofcontaminationresults incrackingduringheatingand iscaused by such things as fingerprints which contain chlorine, otherhalogen-containingmaterials,and ironoxide.Thisproblem isavoidedbyusingcleantoolsandcarefullycleaningpartsbeforetheyaresubjectedtoheat.

FromtheB-70AircraftStudycomesthesedetailsoftheconstructionoftherearfuselage(NorthAmericanRockwell)

Theintermediatefuselagewasdividedintoforeandaftsectionsandcontainedanumberoffueltanksandairductingfortheengines.(NorthAmericanRockwell)

AllstandardsheetmetalpracticeswereusedinformingXB-70titaniumparts, but with special care. These basic forming operations wereperformed at room or elevated temperatures depending on configuration,and a part with compound curvatures may have required drop-hammerforming because of its unique shape. Since forming of titanium is bestaccomplished at a slow rate, but drop hammering is a rapid operation,elevated temperature forming was mandatory. Heating for drop-hammerforming was accomplished by quartz lamp, by electrical resistancemethods,andbyheating inconventionalrecirculatingair furnaceswithaquicktransfertotheformingdie.

Simple frameswere formed on a rubber pad hydro-presswith a slowdeformationrate.Thiswasperformedat roomtemperature, resulting inapartiallycompletedshape.Itwasfollowedbyhot-sizing.Thesoaktimewasusuallyabout10minutes,withthediebeingthesamesteeltoolasisusedfor hydropress preform operations, additionally augmented with matchedsidemembers.

Power-brake forming was used to produce angles, Z-sections, hatsections,andchannelsonstandardbraketools.Theseshapesusuallywereformedatroomtemperaturewhereaninherentspringbackofapproximately30degreesintheincludedangleoccurred.

NAAeventuallyreachedthepointwiththeXB-70whererejectionratesinformingandworkingtitaniumwasatnegligiblelevelsandthecompany

was able to produce parts to close tolerances that permitted efficientassemblysequenceswhichincludedfusionandresistancewelding,rivetingandbolting.

TheValkyrie’snoseradomewasconstructedofaproductcalledVibran;itwas laminated to ensure protection of all the electronics it carried.Allthese different metal types, the comprehensive stress analysis, elasticanalysis, loadfactors,andthemyriadofother tests thatweredoneduringtheinitialdesignphase,comprisedoneofthemostambitiousprogrammesin the construction of an airframe. Mach 3 did not come easy for theValkyrie,butitwouldcome.

BringingthepartstogetherMajor airframe mating commenced with the joining operation of thefuselageaftandforwardcentresectionsonMayl8,1962andprogressedtoacompletionoffuselagejoiningonJulyl8.Subsequently,majorproblemsin structure repair,wing to fuselagemismatch and fuel tank sealingwereencountered.TheseproblemsdelayedcompletionofwingjoiningonAV1from14January1963until24April1964.

The sealing of the fuel tanks to essentially a zero leakage level wasrequirednotonlytopreventfuelleaksbutprimarilytopreventdissipationof the gaseous nitrogen which was used as an inerting agent in the fueltanks. The basic fuel tank sealingwas accomplished by ametal-to-metalseal provided by welding or brazing in the process of joining individualpanels.Thecriterionforsealingrequiredthatatankholdairatapressureof10poundspersquareinchwithso-called‘zeroleakage’.Sincetheaccuracyof the measurement of leakage was not absolutely precise, an indicatedleakageoflessthan10cubicinchesperminutewasconsideredacceptable.This isequivalent toallowingonehole thediameterofahumanhair ina3,000squarefootsurface.

To locate the leaks, the tankswereeithervacuumorpressurecheckedutilizingvariousmethodsofleakdetection.Detectingleakswasarepetitiveoperation, with lesser leaks showing up as larger leaks were eliminated.Leaks which were approximately .050 to .060 inches in diameter werelocated by application of a soap solution over the suspect area withincoming air creating bubbles at the point of leakage. Another methodutilizedfordetectingsizableleakswastolocatethepointbyanultrasonicdevicewhichdetectedthepassageofairthroughanorifice.Astainingdye

activatedbyammoniadrawnthroughtheholeswasusedtooutlinesmallerorpinpointholes,whilealmostinvisibleholeswerelocatedbymeansofaheliumgassniffer.

Thepart-assembledAirVehicleOneonitsownlandinggeariswheeledtothenextstageofthebuild.Itappearsthatthemachinehasbeenfittedwithsomekindoftemporaryfairingenclosingthenoseequipmentbayandcoversupthecockpitglazing.Someaccountssuggestthatthiswasacoatingof

‘Spraylat’peelablepaint,appliedtoprotectthecompletedarea.(NAA/USAF)

Anotherviewofthepart-completedmachine,presumablytakenatthesametime,butthistimefromtherear,showingtheuppersurfaceofthemainwingboxisincomplete,buttherearalreadycontains

theverticalfin‘stubs’towhichwilllaterbefittedtherudders.(NAA/USAF)

Prior to the end of 1962 a seal brazing technique was used on theaforementionedpinholeleaksorifadoublertyperepairwasrequired.Thistechniqueutilizedabrazealloythatmeltedatatemperatureofabout1,160°F, applied by a hand-held torch. This process was very critical and timeconsuming,sincenosealingwasaccomplishedif the temperaturewas toolow and secondary damage to the thin honeycomb panel face sheetsoccurredifthetemperaturewastoohigh.Damageofthisnaturetovarious

fuel tank sections caused a heavy workload at the end of 1962.Approximately3000oftheseareashadtobeinspectedandrepairedwheredamagewasfound.

Another process which contributed to delay was the portable nickelplatingutilizedinstructuralrepairs.Asthisprocesswasused,itwasfoundthat if a small fissure or defect existed in the panel, the plating solutioncouldseepthroughintothepanelandcausecorecorrosion.Repairingthisdamage necessitated the removal and replacement of complete steelhoneycomb panels, which in turn further delayed tank completions andsealing.

ItalsobecameapparentduringtheXB-70structuralassembly,thatthin-faced honeycomb panelswere prone to handling damage. The repair andassociated sealing of the damaged panels presented special processingproblems not previously anticipated. The use of brazing and weldingmethods of sealing the thin gauged structure proved very difficult andresulted in formation of structurally unacceptable wrinkles and buckles.Withpreciseprocesscontrol,thesealingprocedureswereusedsuccessfully;however,when thebrazingandweldingprocedureswereused inareasoflimited access or under adverse conditions, panel damage occurred. Thisunacceptable condition initiated investigations to find a sealing methodcompatible with the thin gauged structure under the adverse workingconditionsusuallyexperiencedintanksealing.

Anewmethodofsealingsmallpinholeleakswasdevelopedintheearlymonthsof1963.Thisprocessconsistedofplasma-sprayingaluminiumoveraleakingareaandthenapplyingsixcoatsofDuPontViton-Bsealantcuredat375°F.Thissealingmethoddidresultinsomesecondaryheatdamagetothe structure but considerably less than that experienced with earlierprocesses. Viton sealing was constrained at times during the matingoperationsduetotheflammabilitypotentialwhenweldingwastakingplaceinadjacentareas.

A series of tools were originally programmed to assure the closetolerancesrequiredtomatethewingtothewingstubs.However,inordertoconserve funds, most of the wing joining tools were eliminated in theprogrammeredirectionofApril1961andonlycontoursupport toolswereprovided. This necessitated matching the wing joint by optical methods,involvingthefitoffourcontouredsurfacesalongan80footdistancetoanaccuracy of .008 inches or less.When thiswas initially attempted in late

1962, itwas found that the support surfaces along the lengthof thewingwouldmove and that ambient temperature differentials would alsomovethe two surfaces of thewing andwing stub apart.After several attempts,matching by this techniquewas abandoned and a fittingwas designed toattach to the wing stub to compensate for the inaccuracies in the jointalignmentpermittedbythesimplifiedtooling.Thesematchoperationswereconstrained by the fuel tank sealing required in thewing root stub tanks.Fusionandelectronbeamweldingwereemployedinwingjoining;fusionontheinnerweldandelectronbeamontheouter.Subsequenttoinnerweldcompletion and prior to starting the outerweld, thewing jointwas x-rayinspected and the tanks were pressurized for leak detection. Extensivepreparations were required in support of the external electron beamwelding.Thesepreparationsconsistedofcleaningtheweldjoint,applyingRTV77sealant,andthenplacingasmoothplateoverthesealanttoholdthevacuumboxandelectronbeamgun.

Plywoodprotectionsheetscovermostoftheupperwingsurfacestopreventdamagebypeoplewalkingonthestainlesssteelhoneycomb.Oneofthetwodoorscoveringthebrakechute

compartmenthasbeenfitted,asarethejurystrutsholdingtheruddersinplace.ThisisAV/2andthedateis20January1965.(NAA/USAF)

The first stepof thewingmatewas tobring thewingup to thewingstubandcompletethefinaltrimontheareastobewelded.Shearties–49toeachwing–werethenlocatedandweldedtothewingandstubframes.Subsequenttothisafewcrossshipinstallationswerecompletedafterwhich

theactualjoiningcommenced.

FuelingthebeastThefuelsystemofeachXB-70Awasequippedwitheleventanks,althoughthis itself doesneed someexplanation.Therewere elevenphysical tanks,although most of the NAA documentation states that there were eight –becausethetwoadjacentwingtankswereconsideredasoneunitsincetheywerecontrolledtogetherinordertocontrolthecentreofgravity.Also,sincetankNo.3wasoverthecentreofgravity, itwasusedasasumptankandnot for fuel storage. Five of the tankswere located in the aft part of thefuselageneck,andthreeintegraltankswereinthemainpartofeachwing.On AV 1, tank No. 5 was inoperative due to the unresolved leakageproblems.

Thewingtankswereemptiedfirst.Fromthemaintanks,fuelwasfedtothe No. 3 sump tank as dictated by engine requirements and center ofgravity concerns. At cruise power, fuel flowed from tank No. 3 to theengines at 785 pounds per minute. Fueling and de-fueling wereaccomplishedthroughasingle-pointreceptacleatarateof600gallonsperminute. An adjacent control panel allowed ground crew to select whichtanks were to be filled or drained. A fuel tank sequence panel on thecopilot’s instrumentpanelpresentedagraphicdisplayof tanksequencing.Dual-colouredtapes(whiteandblack)wereusedtoindicatethefuellevelin each tank – white indicated fuel; black indicated no fuel. When thedisplaywascompletelyblack,thetankwasempty.TheintertanktransferoffuelwasautomatedonAV2,butwasaccomplishedmanuallybythecopilotinAV1.

Thisviewgivesagoodideaofthesizeoftheforwardavionicsbayandtheemptyupperhatches.(NorthAmericanRockwell)

WhileunderconstructiontheXB-70hadaprotectivecoatingappliedtohelpprevent‘hangarrash’.(NAA/USAF)

Following studies, it was planned that the third prototype andproduction aircraftwould have included an aerial refueling receptacle ontheuppersurfaceofthenoseforwardofthearticulatingwindshield.Atonestage studies were planned to determine the feasibility for supersonicrefueling.AV3wouldbeusedtomakeaseriesof‘dryhook-ups’between

itselfandanothersupersonicaircraft,possiblyanotherB-70.Fuel was used for cooling various systems through a series of heat

exchangerssuppliedfromthesump(No.3) fuel tank.AtMach3 thefuelcouldabsorbover30,000BTUsperminutefromthehydraulic,engineoil,and environmental control systems. However, towards the end of themissionorduringperiodswhenthefuelflowwaslow(suchasduringin-flightrefuelingwhentheengineswerethrottledback)asecondarycoolingmethodused4,000poundsofwaterthatactedasasubstituteheatsink.Thewaterwasvapourisedatarateof28poundsperminuteinaboilerbythelatentheatfromthesystemsnormallycooledbythefuel.

Gaseous nitrogen was used for fuel tank pressurization and inerting.Twoliquidnitrogenstoragevesselseachholding350poundsofLN2under83psipressure.Avaporisercircuitconverted liquidnitrogenintogaseousnitrogenwhichwasthensuppliedtothevariousfueltanksandlinesunderpressure.Attheendofahigh-speedflight,afuel-to-waterheatexchangerassuredthatthefueldeliveredtotheenginesdidnotexceed260°F.

OxygenintheJP-6wasconsidereddetrimentalbothto thestabilityofthefuelandalsotoaircraftsafety.Tohelpeliminatetheoxygen,thefuelingprocess for the XB-70A was somewhat elaborate. A tanker full of JP6beganbypumpingthefuelintoasecond,emptytanker.Atthesametime,the second tanker was being pressurized with high-pressure dry nitrogenwhichwasbubbledthroughtheJP-6asitwaspumpedin.Thedrynitrogendroveoutanyoxygeninthefuel,andthe‘clean’JP-6wasthenpumpedintotheXB-70alreadypartiallypressurizedwithnitrogen.

AV1takesanothertripoutside,thistimeundertheglareofapairofhugefloodlights.UnliketheRS/SR-71beingbuiltingreatsecrecyattheLockheedSkunkworks,NAAwereproudofwhatthey

werebuildingandnevermissedachanceformorephotographs.(NAA/USAF)

Manyof the other systems of theXB-70were also revolutionary andwhilethewingmateandtanksealproblemswerebeingsolved,otherpartsoftheaircraftwerebeingworkedon.

AcomfortableenvironmentThe ‘shirt sleeve’ environment for pilotswas a concept unheardof at theflight speedandaltitude thatwasmarked for theXB-70.The shirt sleeveenvironmentwasaccomplishedmainlybyuseofahigh-pressurebleedairsystem, supported by Freon refrigeration units. This twofold systemmaintained the cabin pressure at 8,000 feet. If a rapid decompressionoccurred due to mechanical or some other failure, the pilots couldencapsulate and fly the XB-70 from within clamshell capsules. Therefrigeration system relied on two Freon units that helped cool the crewcabinandtheequipmentbays.Theseunitsusedhigh-pressurebleedair torun the Freon compressor turbines. The air entered at 850° F, but by thetime the additionalbleedair for the fuselagepressurization left theFreonexchangers,thetemperaturewasreducedto45°F.Anyareathatwastobecooledactuallyhadtinyholesperforatingthewalls.Airwasthencirculatedintoaglass-linedplenumcellattheendoftheporouswallandductedbackto theheatexchangersafterpassing throughawatervaporizer.Therewasevenaprovisionfora liquidammonia tankso that theammoniacouldbeusedasapowerful,short-termevaporativecoolantasabackupforwhenthewater tankwasemptyat theendofa long flight.Throughallof this, thecrewcabinwasleftatacomfortabletemperature.

ThetwinverticalsareinstalledonAV-1.(NAA/USAF)

AV2comestogetherintheassemblyhangaratPalmdale.Theaircraftsitsonjacksreadytotestthewing-foldmechanism.(NorthAmericanRockwell)

EnginebreathingAllengineersdesigningsupersonicaircrafthavetofindawaytoslowdownthe engine intake air to subsonic velocities. In theXB-70A, two separateand independent inlet duct systemswere provided, each delivering air tothreeengines.Each intakewasabout seven feethighat the splitter.Fromthere theairwasductedapproximately80feetbacktoaplenumchamberjust ahead of the engines. The plenum chamber was the size of a smallbedroom. The rectangular-section intake was manufactured from brazedstainless steel honeycomb sandwich panels except for H-11 tool steelsections around the front of the engines. The primary function of theHamilton Standard inlet control systemwas to position the shock wavescreated at supersonic speeds so that the air entering the engines wassubsonic. Each duct system incorporated a rectangular variable-geometryinlet,avariableareabypass,aboundarylayerbleedaircontrol,andanairinletcontrolsystem(AICS).Varyingtheinletgeometrywasaccomplishedby amovable panel system in each inlet duct. Each inlet had three fixedramps, three movable panels, plenum divider panels that isolated fourcompartments just inboardof theinlet,andhydraulicactuators topositionthe panels. These ramps and panels served three primary functions: theyformed the inletductwall, setupashockwavepatternduringsupersonicflight,andprovidedameansofbleedingtheboundarylayerair.

ThecockpitenvironmentalsystemvariedbetweenAV1andAV2and3asseeninthisschematicshownintheB-70Study.(NorthAmericanRockwell)

Approximately90%oftheaircompressionwasperformedintheinlet,not in the engine. The inlet was designed to reduce the free-stream airvelocity fromMach 3 to less than Mach 1 by a series of shock waves,beginningwiththeprimaryshockwavecreatedbytheleadingedgeofthesplitterductandendingaftoftheminimumthroatarea.Ideally,theterminalshockwavewouldhavebeenattheminimumthroatarea.Butfactorssuchasgustdisturbancescould‘pop’theshockoutsidetheinlet,resultinginan‘unstart’andpossibleengineflameout.Engineersdecidedtoacceptasmallperformancepenaltyandmovetheshockwavefurtheraftinanattempttopreventthis.

Twosecondaryshockwavespriortotheductentrancewerecausedbybreaksinthesweepofthesplitterduct.Theairfollowedacircularrouteintheduct,whichcausedanotherseriesofshockwaves.Theterminalshocktosubsonicvelocitywasthelasttooccur.Threemovablepanels,positionedbytwohydraulicactuators,openedorclosedthethroatareatomeetengineair requirements; the maximum opening was 48 inches wide while theminimumwas19inches.Athree-positionswitchinthecockpitallowedthepilotstochoosehowfarbacktheterminalshockwavewouldbepositioned.Formaximum range andmost efficient air recovery, the shockwavewaspositionedforward.However,iftheaircraftwasflyingthroughturbulentairor manoeuvring, the shock would be positioned further back. The aftposition provided the most stable operation and basically precluded the

shockfrombeingexpelledthroughthefrontoftheduct.

ThehugeairintakesontheXB-70areclearlyvisiblehere,withthesplitterplatealmostretracted.Thesizeoftheintakesaregivenscalebythepeoplemillingaroundtheaircraftduringtheroll-out

ceremony.(NorthAmericanRockwell)

Excess inlet air was jettisoned overboard through six pairs of bypassdoorslocatedontheuppersurfaceofthewingbetweenandslightlyforwardoftheverticalstabilizers.Thesixsetsofdoorsweredividedintotwosetsoftrimmer doors and four sets of primary doors. Each pair of doors wasinterconnected(onedooropeneddownwardandtheotheropenedupward).Thebypassdoorsprovidedfromzeroto2,400squareinchesofbypassarea.

Thethreepanelsinthethroatofeachinletwereperforatedsothatslow-moving turbulent boundary layer airwas bled to ambient pressure on theothersideofthepanelsintofourseparateplenums,eachbleedingboundaryairfromadifferentsectionoftheforwardduct.Thisairwasdischargedattherearofthestepjustaftofthenosewheelwell.Theremainingboundarylayerairwasdivertedintotheenginecompartmentstoprovidecoolingandexitedfromductsaroundtheengines.NorthAmericanbelievedthatductinginlet bleed air around the engines would also effectively cloak theafterburnerfrominfrareddetection.However,littlecouldbedoneaboutthemiles-longtrailofhotgasesgeneratedbythesixJ93s.

Twopairsofunstartsensorswereinasupportpackagelocatedbetweenthe throatpanelhydraulic actuatingcylinder and theoutboardwallof theforward weapons bay. An inlet unstart was regarded as ‘an undesirableconditionresultingfromtheexpulsionof the terminalnormalshockwave

duringflightwhenitisdesiredtohaveitlocatedinsidetheduct’.The air induction control system package was located in the aft

weapons bay, complete with its own environmental control system, butwouldhavebeenrelocatedinanyproductionversion.

Insidetherighthandairductduringtheconstructionphase,lookingforwardtothesplitterplate.(NorthAmericanRockwell)

Theengine‘SixPack’All this air had to go somewhere – and it was straight into one of sixGeneral Electric YJ93-GE-3 turbojet engines, unofficially called the ‘sixpack’.Theenginewasacontinuousflowgasturbineincorporatingamulti-stageaxialflowcompressor,afullyannularcombustor,atwo-stageimpulsereaction turbine, and an afterburner equipped with a variable areaconvergent-divergentexhaustnozzle.Compressorspeedwasgovernedbyahydro-mechanical fuel controlwith an electrical temperature override forexhausttemperatureatmaximumspeeds.

Insidethesameduct,lookingrearwardstowardstheforwardmountsofthreeJ93turbojets.(NorthAmericanRockwell)

Theafterburnerendofthefamous‘sixpack’ofYJ93-GE-3engines.Theynumber1through6,startingontheleftinthisview,andsoengineNo.2showsanopenexhaustnozzle,unliketheothers.

(NorthAmericanRockwell)

The engine was designed for continuous afterburner operation. Thepublicisedthrustwas‘...in the30,000-poundclass’ inafterburner,but theactualfigurewasusuallynotgiven.Inreality,the-3enginemade28,800lbin afterburner at sea level. Non- afterburning performance wasapproximately19,000lb.

TheYJ93-GE-3wasabigengineforitsday–237incheslongand52.5incheswide;itsintakewas42inchesindiameter.Thethrust-to-weightratiowas 6:1, considered very good for the time but paling into insignificancewhen compared to modern turbofans. Moving most accessories to the

airframe allowed for a much simpler engine installation than wastraditional. An engine could be replaced in 25 minutes – a featdemonstratedon severaloccasions.Theenginewasdesigned touse JP-6,basicallyanimprovedkerosenederivativewithimprovedheatstabilityandresistancetotheformationofsolidsintheexhaust.

The J93was the first engine touseair-cooled turbinebladesandalsothe first to use blades made from titanium alloy. This allowed operatingtemperatures several hundred degrees higher thanwas normal practice atthe time. The blades proved somewhat more fragile than their steelcounterparts,andatleast25enginessufferedforeignobjectdebrisdamageduringtheflighttestprogramme.

Despiteaprotracteddevelopmenteffort,theYJ93-GE-3wascompletedonscheduleandpassedits68-hourpreliminaryflightratingtestin1961,intime for the originalXB-70 first flight date.By the time the first aircraftwas actually rolled out in Palmdale, the J93 had accumulated over 5,000hoursoftesttime–including600hoursatmorethanMach2.Aspartoftheengine test programme.General Electric built aMach 3 test facility, andalso used a similar facility at the Air Force Arnold EngineeringDevelopmentCenterinTullahoma,Tennessee.EngineinlettestswerealsoconductedatAEDC,with52hoursoftestsinvolving154enginestarts,109engine stalls, and over 200 inlet unstarts. The inlet in these tests was a0.577-scalemodelusinganactualsmalljetengine.DespitethefactthattheideahadbeencancelledalongwiththeB-70productionprogramme,the-3enginehadalsobeenflighttestedaboardaB-58(55-662)–designatedNB-58A–whereitwashousedinaspecially-configuredcentrelinepod.Somedoubts exist as to wether this aircraft/engine combination ever flew –certainly a few NB-58A ground runs were made with the J93 engine inplace, but the day before the first flightwas scheduled to take place, thefundingfortheNB-58Aprojectwascancelled,andithasbeenclaimedthattheNB-58A/J93 combination never took to the air. The special podwasremovedandtheNB-58AitselfwasconvertedtoaTB-58AandlaterflewchasemissionsfortheXB-70AatEdwardsAFB.

TheNo.2engineisremovedfromAV1.Engineaccesswassogood,thatacrewcouldchangeanenginein25minutes.(NorthAmericanRockwell)

The YJ93 fuel system consisted of an engine-driven, dual element,constantdisplacementgear-typepumpthatincorporatedacentrifugalboostelement that supplied 32 dual-orifice fuel nozzles in themain combustor.Anadditional32fuel injectorsfedtheafterburnerasneeded.Theignitionsystem consisted of a low-tension capacitor discharge unit that housed 4-jouleand20-joulecircuits.Duringnormalgroundstartsthe4-joulecircuitwasused; during low-temperatureground starts and for all air starts boththe4-and20-joulesystemswereused.

TheGeneralElectricYJ93-GE-3enginewaswasveryadvancedforitsdayandwasdesignedforcontinuousafterburneroperation.Thebox-likestructureunderthenoseistheenginehydraulic

system,plusgearboxandshafttake-offtodriveaircraftsystems.(GEEngines)

ThejackssupportingtheweightofAV2weremassive–theyhadtobe!AV2awaitstheinstallationoftheengines.(NorthAmericanRockwell)

Each enginewas equippedwith a 3,500-psi hydraulic pump thatwasseparate from the airframe-mountedpumpsandwasusedonly for enginecontrol. The engine used hydraulic power to move the front and rearvariablestators,andtheprimaryandsecondaryexhaustnozzles.

Becausetheywereprototypeengines,andtheXB-70Atestprogrammewasnotexpectedtoflyintoknownicingconditions,theengineswerenotequipped with anti-icing systems. However, the basic J93 designincorporated all the necessary structural facilities (internal piping for airsupply,mountingpads,etc.)forananti-icingsystem.

The XB-70A was ahead of its time in providing a ‘thrust-by-wire’system. The throttle levers in the cockpit sent electrical signals to eachengine control system.This in turn provided amechanical linkage to theengine that integrated the operation of the main fuel control, afterburnerfuel control, and primary nozzle area control. In addition to theconventionalthrottles,emergencythrustcontrolswitcheswereprovidedonthe centre aisle console and also in each escape capsule. Having electriccontrol of the engines was one of the keys to providing limited aircraftcontrolfromwithinthesealedescapecapsules,butoddly,theenginethrustcouldonlybereducedfrominsidethecapsule.Theconceptwasthatoncethe aircraft slowed down and lost altitude, the pilots could open thecapsulesandcontroltheaircraftnormally.

‘ThreeGreens...’Cleveland Pneumatic manufactured the tricycle landing gear had dualsteerable nose wheels and four wheels on each main wheel bogie. The12,000 pound weight gear retracted into environmentally controlledcompartmentsinthelowerfuselage.Nosegearretractionwasaft;themaingearwent throughacomplicated folding and rotation sequence to fit intorelativelysmallcompartmentswhilenot interferingwith theair intakesorengine plenum chambers. Thewheelwell doorswere kept closed exceptwhenthegearwasbeingextendedorretracted.

Eachmaingearconsistedofamainshockstrut,dragbraces,actuators,andafoldingbogieassemblywithfour40-inchdiametermainwheelsand40xl7.5-inch36-plyB.F.Goodrichtyres,twobrakes,anda16x4.4-inchbrakereferencewheel.Thetyreshadhigherloadratingsthanhadeverbeenachievedbeforewithinthe40xl7.5envelopeandoperatedathigherspeedsthaneverbeforeonaheavyaircraft.

The tyres themselveshadasilvercolourasa resultofaheat-resistantmaterial being impregnated into the rubber during construction and alsopaintedontheexteriorsurface.Thebrakesweresomewhatunique,withastack of 21 stationary and 20 revolving disks located between opposingwheels and shared between them.The stationary discswere splined on astator ringcageand the rotatingdiscs splined to the torque tube towhichthewheelswereattached.ThewheelsranonbearingsfitteddirectlytotheH-11 forgedsteelbogie insteadofonanaxle.Since thebrakediscswereseparatedfromthewheels,muchmoreefficientcoolingwasachieved.Still,atmaximumeffortthebraketemperaturesexceeded2,000°Fandabsorbedover200millionfoot-poundsofkineticenergy.

The ‘brake control system of the B-70 was a new concept of fullyautomaticregulationofbrakingtheairvehicleuponagiveninputcommandbythepilot.Brakingtorqueoneachofthefourbrakeswasindividuallyandautomaticallycontrolledtoprovidemaximumretardingforce,regardlessofrunwayconditions,withoutskiddingthetyres.Thebrakingsystemwasnotof the conventional anti-skid (‘On’-‘Off’) type but a much more refinedtypeofcontrolwhichutilizeda‘fifthwheel’toprovideatruegroundspeedreference

Thissmallfifthwheelandonemainwheelcontainedspeedsensorsthatsent data to the antiskid computer. The difference in rotational speedsbetweenthesetwosensorsindicatedtheamountofslippage.Sincethefifth

wheelhadnoloads,itwasassumedthatitalwaysrecordedactualspeed.Ifan excessive speed differential existed, the computer then relieved somebrakepressuretothatbogie.

Themainwheelbogieretractionsequencewassomewhatcomplicated,inthatthewheels,struts,brakesandaxleshadtofitintoaverysmallspace.

Firstthetrailingwheelroseupwardsuntilvertical,theentirebogietruckrotatedinboardthroughninetydegrees.Oncethatwascomplete,thestrutwasabletorotatebackwardsthroughninety

degreesintothewheelwellasshowninthissequence.

Notethedottedreferencelinepaintedonthefuselageandstruts.Thiswasusedasavisualreferenceinordertocheckpositions.

Theso-called‘fifthwheel’usedfortheanti-skidisvisiblebetweenthetwomains.(allNorthAmericanRockwell)

The nose gear consisted of a shock strut, drag brace, torque links,actuators,asteeringservoactuator,andtwo40-inchwheelsand40x17.5-inch36-plyBFGoodrichtyres.Thenosewheelscouldbesteeredupto58degreeseithersideofcentreattaxispeeds,orupto35degreeseithersideofcentreduringtake-offandlanding.

Three28-footdiameterring-slotnylondragparachuteswerehousedinanenvironmentally-controlledcompartmentontopofthefuselage,eighteenfeet from the rear of the aircraft. A 30-inch diameter spring-loaded pilotparachute pulled an 11-foot diameter extraction ’chute which in turndeployed the threemain ’chutes.Theupward-openingcompartmentdoors

werelockedintheopenpositionwhenthepilotcommandedthechutestodeploy,whichcouldbeatspeedsupto200knotsafter themaingearwasfirmlyontheground.

The design,manufacture and installation of the landing gear was notstraightforward, as North American’s Design/Programmatic Impacts logshowsforjustoneperiod.

28June–5July1963–Reworkofthemainlandinggearuplockboxrequiredduetonegativestressmargin(61%)duetoacombinationofgearretractionsnubbingloadsandwingbendingloads.

30Aug–9Sept1963–Replacedonenoselandinggeartrunnionfittingon AV 1 due to cracks and distortions that occurred after weld rework.Engineeringsimplifieddesigntoreducemachining

18Oct – 15Nov 1963 – TheLH landing gearwas damaged duringrailroadtransittoNAA.Railcarbumpingapparentlycausedwiretiedownsto break allowing gear to shift. Tyres were badly chaffed and declaredunusableOthercomponentswerealsodamaged.Nostructuraldamage tothemainstrutandbogiebeamassembly.

13March–8June1964–OperationaltestonAV1showeddragchutedooroperationalspeedsoexcessivethatitcouldcausestructuraldamage.ActuatorchangetodecelerateactionwasaccomplishedontheDragChuteandoperationscompleted8June.

3April–10April1964.DuringcyclingofAV1RHmainlandinggeardownlockH11supportfittingfailedduetocracksinducedbyweldbeefup.The first reworked part was delivered to Engineering Structure Lab fordestruction testing. During test one of the supporting components failed.Previously (6 April) B-70 Management decided to make one set ofsubstitutepartsof4340steelasabackup.On9Aprilthefittingcompletedthe 500 cycles of limit load followed by one ultimate load applicationwithoutfailure.

18June–2July1964.DuetoerraticoperationsofthelandinggearonAV 1, the emergency landing gear 4 position valves required rework toreducesurgeeffort,Engineeringwasreleasedonl8Juneforvalverework.In addition new line, restrictors and check valves were added to thehydraulic installation. Additional rework was required due to threadstrippageof thearmattachbolt on thebogie beam.The thread strippingwasduetoextremeforceactionduringoperations.Theboltwasredesignedandthemethodofrotatesequencingwasrevised.On1JulytheRHbogie

foldlockarmfailedonAV1duringoperations.TheAV2partwasinstalledonAV1tocontinueoperations.Cleveland

Pneumatic, the gear supplier were on strike at this time. A strengthenedpart was designed at NAA, made from U3UO steel and approved byClevelandPneumatic,tobemadelocallytosupportAV1,2andspare.

Themassivemainlandinggear–eachtruckwasmadefromH-11toolsteel.ThetyreswerespeciallymadebyBFGoodrichofheatrepellantaluminiumimpregnated‘silver’rubber.

Theupperpictureshowsthebrakediscsbetweenthewheels.(NorthAmericanRockwell)

MachiningtitaniumWhen titanium alloys were first introduced as a structural material, theywere considered very difficult to machine compared to more commonmaterials.Researchandexperienceprovedthattheycouldbemachinedatrates economically comparable to other aerospace alloys and that good

surfacefinishescouldbeobtained.Evenso,extremecarewasnecessaryindevelopingandcontrollingproceduresinselectingtoolmaterials,coolants,andtherightcombinationofspeeds,feeds,andtoolgeometry.

Maximum rigiditywas essential in any equipment used inmachiningtitanium to the close tolerances necessary. Cooling of parts during amachineoperationwascriticalbecauseofthegreatneedformaximumheatdissipationandtopreventchipsfromweldingtothecuttingtooledge.Thebest cooling was achieved with a mist generator as atomized coolantsprovidedamuchhigher cooling rate than that accomplishedwith floodedcoolants, and the force of mist application removed the chips from thecutter and work contact areas, thus minimizing chip welding. Non-chlorinated cutting fluids were used to prevent possible stress-corrosioncrackingintitanium.

Muchexperimentationrevealedthatsharphelixanglesoncuttingtoolsproducedabettershearingangleandthusabetterswarf-chipclearanceandremoval. It was also discovered that a single heavy cut produced betterresults thanaseriesofsmallerones.Inthewordsofonemachinist‘...youdonottickletitanium!’

Todaychemicalmillingiscommonplace–butatthetimeitwasanew,patentedprocess,developedbyNorthAmerican,andwas recognizedasaprincipal method for removing excess metal to meet close tolerances,particularly on curved surfaces where conventional machining is all butimpossible.Itbecamewidelyusedforaluminiumandsteel,aswellasfortitanium.

Development and evaluation of etchants and maskants used tochemical-milltitaniumanditsalloyshadbeendoneinconjunctionwiththeX-15 andXB-70programmes.Metal removal ratesof 0.06 inchper hourwith tolerances of ±0.002 inch were regularly achieved by severalcommercial sources, enabling the process to be cost-competitive withconventional machining methods. The importance of this process inproviding a way to remove excess weight from parts made from sheettitaniumfortheXB-70cannotbeover-emphasized.

Extensive testing was performed on chemically milled titanium todetermineifthesurfaceroughnesswasaffected.Theeffectwasdeterminedbyroughnessmeasurementsandbyfatigue-testing.Resultsindicatedthataproperlycontrolledbathreducedtheacuityofsurfacescratchessomewhat,but no effect was found in the fatigue behaviour of chemically milled

sampleswhencomparedtotheresultsofparentmetalfatiguetests.

HydraulicsandElectronicsSixairframe-mountedaccessorydrivesystem(ADS)gearboxes,eachshaft-drivenbyacorrespondingengine,weremountedinseparatecompartmentsforwardoftheengines.Allsixgearboxesdrove4,000psihydraulicpumps,and Nos. 2, 3, and 4 engines also drove AC electrical generators. Theaircraftwasnormallypoweredby twogenerators (Nos.3 and4),but anyoneof the threewascapableof supplying theentire load if required.Theconstant-speed(8,000rpm)generatorsprovided240/416-volt,3-phase,400hertzpowerthroughstep-downtransformers.Thehydraulicpumpscouldberun‘inreverse’andwereusedtostarttheengines.Havingtheaccessoriesmountedontheairframeinsteadofontheengineallowedeasierandmorerapidenginemaintenance.

Sixengines,six4,000psihydraulicpumpsexternaltoeachengineandthreeACgenerators.(NorthAmericanRockwell)

Altogether, each XB-70A used 85 linear actuators, 50 mechanicalvalves, 44 hydraulicmotors, and about 400 electrically-actuated solenoidvalves.

Morethanamileofvarioussizetubingcontained3,300brazedand600mechanicaljoints.Toavoidthelargeweightpenaltyofprovidingacoolingsystem, all the actuators and valves were designed to withstand hightemperatures.

Conventional couplings were not used in the various fluid systems(hydraulic, fuel, oil) to save weight and (unsuccessfully) eliminate thepossibilityofleakage.Instead,allhigh-pressurefluidlineconnectionswere

brazed;low-pressurelineswerewelded.NorthAmericanestimatedthatthetechniquesavedover10,000pounds.

Approximately 220 gallons of a special high-temperature hydraulicfluid called ‘Fluid 70’ (actually namedOronite 70)were used.This fluidcould operate continuously at 450° F and intermittently up to 630° F.AlthoughthefluidwasmuchbetterthantheoriginalOronite8200thathadbeen selected, it still left much to be desired and required constantreplacement due to breaking down after prolonged exposure to hightemperature.

ElectronicsEach aircraftwas equippedwith twoAN/ARC-90UHF command radiosproviding3,500channelsbetween225.00MHzand399.95MHz,andhadabuilt-inguardreceivertunedbetween238-248MHz.OnAV1onlyoneoftheUHFsetswasactive, theotherbeing instandbymode.OnAV2bothsetscouldbeusedsimultaneously.Antennaswere locatedonboth the topandbottomof theforwardfuselage.AnAN/AIC-18intercomallowedthetwopilotstotalktoeachother.AnAN/APX-46transponder(IFF)setwasinstalledonbothaircraft,moreforairtrafficcontrolpurposesthananythingelse.Again, antennaswere located on the top and bottomof the forwardfuselage.

Oppositepage:ThefrontpageofNAASkywriterEmployeeReportdatedSeptember1964showingtheprogressofconstructionofAirVehicleOne.Interestinglyinsomeplacestheaircraftiscalledthe

XB-70,inothersitisreferredtoastheXB-70A.(NAA),

EachXB-70Awas equippedwith anAN/ARN-58 instrument landingsystemandastandardAN/ARN-65TACANradionavigationsystem.TheTACAN installation was a far cry from the sophisticated bombing-navigation systemdevelopedby IBM, andwas generally consideredonlymarginallyacceptable for test flights.Without theIBMbomb-navsystem,theXB-70Asdidnothaveaninertialnavigationsystemandwereforcedtorely on dead-reckoning and TACAN. Fortunately, the chase aircraftgenerallyhadbetternavigationsystems,andtheXB-70swerealwaysunderpositiveradarsurveillance.

MilitarysystemsAsdelivered,neitherXB-70Ahadanymilitarysystemsinstalled,otherthana nonfunctional weapons bay. AV 3 would have been equipped with afunctional weapons bay and prototype offensive avionics. The plannedcapabilitieswereimpressive,however.

Theweaponsbaywassized tohouseamultitudeofbombs, includingthermonuclear devices up to 10,000 pounds each, 20,000-poundconventional bombs, various smaller conventional bombs, chemical andbiologicalweapons,oruptotwonewair-to-groundmissiles.Themissileswere tohavea rangeof300-700nmandanaccuracyof less thanamile.Othermissiles(probablyGAM-87Skybolts)weretobecarriedonexternalhardpointsunderthewings,atleastinsomevariationsoftheB-70.

The IBM-developed AN/ASQ-28(V) bombing-navigation and missileguidance subsystemwas intended to be usedbybothWS-110AandWS-125A before the nuclear-powered bomber was cancelled. The bomb-navsystemwouldhaveincorporatedastartracker–animprovementofaunitoriginallyintendedfortheNavahointercontinentalcruisemissile–toallowprecise navigation without the use of radio aids. At some points in itsdevelopment, the ASQ-28 was to incorporate both forward- and side-looking Doppler radars – the side looking units were intended to allowrelatively‘stealthy’approachestothetargets.

JusthowfarAV2wasoffthegroundisvisibleinthisphotograph.Partofthefuselageisstillunpainted,andtherearestillelevonstobefitted.(NorthAmericanRockwell)

Thesystemwasdesignedtobeequallyaccurateatlowlevelorat2,500knotsand100,000feet.Thesearchradarhadarangeof200nauticalmiles,

andcouldaccuratelytracktargetsat125nm.Aresolutionof200feetatarange of 50 nautical miles was expected. The avionics used variouscomponents:theradardataprocessorfromGoodyear,anX-bandradarfromGeneral Electric, with General Precision Laboratories providing theDopplerprocessor.AtleastlimitedtestingwasundertakenusingC-54,RC-121,JB-29,JRB-57,andRB-66aircraftassurrogates.

Asoriginally envisioned, thedefensive avionicswould consist of fiveelements:activeandpassivewarningdevices,threatevaluationequipment,electroniccountermeasures,infraredcountermeasures,andchaffdispensingrockets.Again,atleastinitiallythesystemsbeingdevelopedforWS-110AwouldalsohavebeenusedontheWS-125Anuclearaircraft.Earlythoughtwas given to adapting theAN/ALQ-27 jamming system being developedforlate-modelB-52stotheB-70,butthephysicaldifferencesintheaircraftmade this impossible. A revised system, using many of the techniquesdeveloped for the ALQ-27, was to be capable of noise jamming thirtyradarssimultaneouslyandtrackbreakingagainstafurthertensimultaneousradars.Itwouldcoveralmosttheentirefrequencyrangefrom50to16,000megacycles.Atvarioustimes,theAirForceandNorthAmericanexploredthe application of defensive missiles, including a unique ‘flying saucer’design called a ‘lenticular defense missile’ as well as more conventionaldesignssuchasmodifiedGAR-9s.Onestudy(SR-197)endorsedequippingthesemissileswith a ‘neutron kill’warhead thatwould render the enemymissilewarheadsinoperativewithoutexplodingthem.

TheB-70WeaponsSystemOfficeprovideddiagramsforallthegroundservicingequipmentthatwouldhavebeenneededshouldtheB-70haveenteredoperationalservice.(AFMC)

AlertPodOneofthemoreinterestingsystemsbeingdesignedfortheoperationalB-70wastheAlertPoddevelopedbyBeechAircraft.Thiswasenvisionedasameans to provide the B-70 with a self-sufficient ground power systemduringdeploymentstorelativelyausterebases.

OneoftheoperationalrequirementsdefinedbySACwasthattheB-70shouldbereadyfortakeoffinlessthanthreeminutesafterthecrewenteredtheaircraft. Inorder toaccomplish this,manyof theB-70systemswouldhavetohavealreadybeenpowered-uptomaintainthematcorrectoperatingtemperatures.Thiswouldrequireexternalpower.

Insteadofrelyingontransportaircrafttocarrytheexternalpowercartsfor theB-70, a decisionwasmade todesign all of thenecessary systemsinto a streamlined pod that could be carried by the B-70 itself, at leastduring subsonic flight. This pod would provide all necessary hydraulic,electrical,andpneumaticpowertotheaircraftwhileitwasonground-alertstatus,andalsoduringmaintenanceactivities.

Thepodwasdesignedtoattachtothecentrelineofthelowerfuselagebehind the weapons bay, roughly under engines No. 3 and 4. It wasequipped with its own retractable wheels that were used after it wasdetached from the aircraft. While sitting on its wheels, the pod wasapproximately 6 feet high and 30 feet long. Three built-in hoists (two atfront and one rear) allowed the pod to be mated to the B-70. The podcontainedtwosmallgas turbineenginesdrivingsixhydraulicpumps(onefor each J93) and two generators. The hydraulics allowed each of theaccessorydrivesontheB-70tobepoweredinordertostarttheJ93s.Thepodcouldalsocooland/orheattheB-70crewcompartmentandequipmentbaysasneeded.Anareaintherearofthepodallowedthegroundcrewtostore tools andminor parts,while a large JP-6 fuel tank at the frontwassufficient for nine hours of unrefueledoperationof the turbines.Thepodcould be controlled locally by the ground crew, or from the crewcompartmentatthecopilot’sstation.

EachoperationalB-70wasscheduledtohaveitsownalertpod.Beechand fourteen other companies submitted proposals for the pod to NorthAmericanon27October1958, andNorthAmerican announcedBeech asthewinner on 23April 1959.At the time the podwas considered highlyclassified andwas describedonly as ‘a special power device’.Amockupwas inspected and approved on 1 August 1959. A prototype unit was

supposedtohavebeencompletedby1October1961,withproductionunitsavailable from August 1963, but with the cancellation of the productionrun,noalertpodswerecompleted.

Alsoproposedwasagroundsupport‘AlertPod’thatwouldhaveenabledtheB-70tobescrambledfromalertinjustthreeminutes.Itwasdesignedtosupplyallelectricalandhydraulicrequirements

neededtostarttheengines.(AFMC)

AirVehicle3VerylittlehaseverbeenwrittenaboutAV3,thethirdValkyrie.AV3wastocarry tailnumber62-0208,but itwascanceledon15February1964,andnevercompleted.ThedesignforAV3wascompletedon31October1963,and because many of the previous technical problems such as thecomplicatedbrazingtechniques,theredesignofthehoneycombpanelsforfabrication, and the elimination of assembly problems had already beensolved,itwasnotlongbeforetheconstructionofAV3wasunderway.

Aswehavealready seen,during theconstructionof the thirdaircraft,theAirForcewasdesperatelysearchingforways tosave theprogramme.They had devised numerous plans to save something of AV 3. All thealternatives were based on pared-to-the-bone proposals that wouldhopefully yield information on high-performance vehicles, including dataon speed, payload, altitude, and duration of flights at high speed. Someeventually happened – in particular the NASA-funded SST programmetesting,butmuchwasnottobe.

Over theyearsmanymythshavearisenover the thirdValkyrie.Somewouldhaveitthatitstillsurvivesinapartiallybuiltstate,allegedlytucked

away in Site 8 of the former NAA plant at Palmdale, along with theunaccounted for remainder of the J93-3 engines built for the programmealongwiththewoodenmock-up.

Certainlyitistruethatalargepartofthethirdmachinewasoncontractwith100%oftherawhoneycombandsheetmetalrequirementalreadymet,andaround90%of theextrusionsalreadysupplied toNAA.Recordsalsosuggest that theCentalAirDataSystemand theAuxiliaryGyroPlatformSystemhadcompletedacceptancetestsandwasawaitinginstallation.

However,itseemsthateverythingwasscrappedyearsagoandnothingofthethirdmachinesurvives.

Andfinally–aFinishOnecommentoftensaidabouttheB-70wasthatitwasahugetarget.Theconceptof‘stealth’wasverymuchinitsinfancyin1960,butengineersatLockheed and North American already understood that reduction of theradar and infrared signature of strategic aircraft would at least delaydetectionbytheenemy.TheshapeandmaterialsusedbyLockheedintheA-12OxcartandRS/SR-71Blackbirdwerespecifically intended to lowerits radar signature. Several detailed studies into the signature of theB-70weremade,andprovidedabasisforreductionattempts.

During the short YB-70 development period, the Air Force directedNorthAmericantoinvestigatemeanstoreducetheprobabilitythattheB-70would be detected. Preliminary investigations were made into applyingvariousradarabsorbingmaterialstotheairframe,particularlytheinsidesoftheairintakes.However,mostoftheNorthAmericaneffortappearstohaveconcentratedonreducing the infraredsignatureof theaircraft.ExhaustingcoolairaroundtheJ93engineswasonemeansofachievingthis.

As part of its research, North American developed a paint ‘finishsystem’ that provided a low emittance at wavelengths used by Sovietinfrareddetectingdevices,whileradiatingmostoftheexcessheatfromthesurfaceinwavelengthsnotnormallyundersurveillance.Thefinishutilizedalowemittancebasecoatwithanorganictop-coatthatwastransparenttoenergy in the1 to6micron range.The top coatingwas strangelyopaqueandhighlyemissiveatwavelengthsbetween6and15microns.Thisfinishwasrelativelyinvisibletoinfrareddetectingequipment,whilestillallowingtheskintoradiateexcessheatoverboardtomaintainitsstructuralintegrity.

Two different coatings were developed, one for areas that reached a

maximum of 485° F, the other for areas up to 630° F. The first, Type I,consistedofEnglehardIndustriesHanoviaCeramicMetallicCoatingNo.2thatwas0.004mmthick.Overthiswasapplieda11mmthickmixtureof85%FerroEnamelingNo.AL-8Fritand15%HommelNo.5933Frit.

‘Frit’isthetermappliedtoaceramiccompositionthathasbeenmeltedand then fused in a special oven, quenched to form a glass, and thengranulated. Frits form an important part of the batches used incompoundingenamelsandceramicglazes;thepurposeofthispre-fusionistorenderanysolubleand/ortoxiccomponentsinsolublebycausingthemtocombinewithsilicaandotheraddedoxides.

TheType IIbasecoatwasamixtureof40%HanoviaSilverResinateand60%HanoviaL.B.CoatingNo.6593applied0.004mmthick.Thetopcoatwasamixtureof74%3MKel-FNo.2140,24%3MKel-FNo.601,and 2% A1203 applied one millimetre thick. The Type I coating wasactually test flown, having been applied to one panel on the verticalstabilizer of the X-15 rocket aircraft. No observable physical changesoccurred during theMach 4.43 flight. In probability the top coatswouldhavebeenanopaquesilverinsteadofthewhitefinishusedonthetwoXB-70Aprototypeaircraft.

ThefinishsystemwasdifficulttoapplytoanaircraftaslargeastheB-70s, but the engineers expected that further development would yieldimprovements in the process. The most difficult problem was that theunderlyingsurfacehadtobehighlypolishedpriortoapplyingthebasecoat.Inaddition,thebasecoatofbothfinisheshadtobecuredat750°F,whilethetopcoatoftheTypeIIfinishhadtobecuredat1,000°F,creatingalmostaceramicfinish.Acceleratedenvironmentaltestsindicatedthatthesurfacewould prove durable on the stainless steel sections of the aircraft, but itslong-term adhesion to titanium appeared to beweak and additionalworkwould be needed to cure this problem. Both finishes were relativelyimmune to exposure to hydraulic fluid, fuels, oils, and other substancesexpected to be encountered during operational service. Each could bereadilycleanedwithsoapandwater.

‘Itwastime...’assomecommentatorssaid‘...toseewhatthispuppycoulddo!’

ITFLIES!

ThetwoXB-70AswereassembledinanewfacilityonthenorthsideofAirForcePlantNo.42inPalmdale,California,althoughalmostallofthemajorsectionsweremanufacturedelsewhere.

Toprovideanefficientmeansofcompletesystemdevelopmentandtoaccurately demonstrate in-flight performance and safety prior to flight, afullscalefunctionalmockupoftheB-70flightcontrolsystemwasdesignedandbuilt.This flight control system simulatorwas designed to verify thesystemdesign,toallowevaluationofsystemperformanceincludingactualrepresentationofsystemnon-linearitieswhichweredifficulttodescribeforsystem analysis, to demonstrate compatible subsystem integration, toprovide system familiarization for flightmaintenance crews, and to somedegree, demonstrate reliability and isolate potential reliability problems.Thesimulatorconsistedofthosesystemsandcomponentsnormallyusedinaircraftcontrol,

The simulation effort in the development of the flight control wascontinuous beginning at initiation of preliminary analysis and ending atcompletionof flight testsupport. Initialsimulationsconsistedofcompleteanaloguerepresentationsofpilot,controlsystemandaerodynamics.Asthesystem development progressed and experimental or actual equipmentbecame available, the analogued simulations of the control loop werereplacedbytheirrealcounterpartswiththecompletesystemavailableandinoperationbeforeflight.

Beforeflight62-0001-otherwiseknownasAV1-hadtoundergolandinggeartests.(NAA)

AV1sitsinsidethehangar,readytobepulledouttomeetthepublic.

Theflightcontrolsystemsimulatorpermittedcompletepilotevaluationof the system throughout the mission of the B-70 while in a realisticenvironment, while the development phase emphasized the testingassociated with system performance and the effects of componentcharacteristics.

The flight control simulator provided a complete air vehicle controlinstallation,withinpracticallimits,fordevelopmenttesting.Thisgenerallyincluded all major cockpit controls and displays, all significant controllinkageswhichaffectedcontrolorfeel,allsurfaceactuatorsandhydraulicand electrical power similar to that provided in the actual aircraft. Airvehiclehardwareandcomponents fabricated toproductiondrawingswereusedwhereverpossible.

Thepilots’forwardviewinthesimulatorwasthesameasthatintheairvehicle.Opticaldisplaysexternaltothesimulatorwereprovidedtoindicate

particularphasesofflight.The development programme was established as three phases. Phase

One was classified as Evaluation and Finalization of overall systemrequirements and components affecting feel characteristics and handlingqualities. Phase Two covered evaluation of preliminary controlconfiguration for design verification and integration compatibility. PhaseThree covered evaluation and verification of final control configuration,demonstrationofflightcontrolandsafetypriortoflight.

AV1outside,beingpreparedforflight-thenumberofgroundsupportvehiclesandequipmentrequiredisnoticeable.(bothNAA)

Detaildrawingsofthemainlandinggearandnosegear.

Initstimetheywereoneofthelargestandstrongestmulti-wheellandinggearsystems.

Experimentalandprototypeflightinstrumentswereinstalledaspartofthe cockpit of the flight control simulator and were subjected toperformanceevaluation.

Hydraulicpower supplied to the flight simulator came fromactual airvehicle system components. System design parameters such as pressure,flow, response, temperature, service life, vibrations, fluid compressibilityand surge characteristics were verified. Characteristics of the individualpumps,variouscombinationsofredundancy,andmasterslavearrangementswere all evaluated. Additional work included verifying the braking andsteeringsubsystemandpilotfamiliarizationandtraining.

AlWhiteandJoeCottondiscussdetailswiththelayoutofthecockpitmock-uplayoutwiththeengineers.(NAA)

NAAReportsindicatethatthecumulative‘flighttime’inthesimulatorcomplexthroughtoJuly1964was758hours,with382hoursfortestpilotsand 376 hours for engineers. ‘Flight time’ was defined as simulatoroperation time with a pilot at the controls performing manoeuvres forhandling qualities or control equipment evaluating, or flying missionprofiles.

RolloutofAV1AirVehicleOnewas rolled out of the hangar onMonday, 11May 1964.TheceremonywashostedbyGeneralAlfredo‘Fred’Ascani,commanderofthe Systems Engineering Group and deputy commander of the Researchand Technology Division at Wright-Patterson AFB, in front of many

assembledguests.TheflightprogrammewastoberunbytheAirForcetogatherdatafor

military programs, but NASA had already signed-on to provideinstrumentationforanumberofSST-relatedexperiments.Itwashopedthatthe Air Force programme would be sufficiently successful to justify afollow-on programme that would probably be run by NASA and aimedmoredirectlyatSSTresearch.

Thegreatwhitebirdisrolledouttomeetthepublicforthefirsttime!

Two months after the rollout, continuing fiscal problems forced theelimination of the partially-builtAV3 and the reduction of the flight testprogrammetoonly180hours-hardlyenoughtojustifytheexpenseofthetworemainingvehicles.

Thefourmonthsfollowingroll-outwerespentperformingtheteststhatarealwaysdoneonfirst-of-a-typevehicles-includinglowandhighspeedtaxitestsonPalmdale’slongrunway,plusenginerunsandfuelsystemtests.

Thesizeandspanofthathugedeltawingisparticularlynoticeable.(bothNAA)

AirVehicleOnedwarfeditssurroundings...

Thefirsttaxitestoccurredon9August,whennumerousproblemswithnose wheel steering, brake chatter, loss of the primary No. 1 hydraulicsystem,andammoniafumesingestedintothecockpitcausedtheteststobeaborted. The nose wheel steering problem was two fold: one was anapparentdriftandtheotherwasanapparentlackofauthority.Thecontrolvalve of the steering unit was replaced which fixed the drift and anindicator was installed in the cockpit to provide the pilot with the nosewheelpositiontoaidinengagementofsteering.Theauthorityofthenosewheel steering was continually ‘squawked’ throughout the flight testprogramme;however,theconditionwasminimizedtosomeextentbypilottechnique.

Fromuphighoratgroundlevel,theValkyrielookedasifitwastravellingsupersonicallyevenwhenatrest.(BothNorthAmericanRockwell)

Above;AV1isrolledoutatPalmdaleon11May1964.GeneralAscaniisatthepodiumontheright.

Guestsinvitedtotheroll-outceremonygatheraroundtheaircraftandprovidesomescaleastotheheightabovetheground(BothNorthAmericanRockwell)

DetailsoftheLandingLoadsInstrumentationpackageinstalledontheXB-70.Thelandinggearwasfilmedinoperation,andtherewerealsocamerasinthenosetocheckrunwaydriftonlanding.

Brakechatterwasbelievedtobecausedbythebrakeliningsnotbeing‘bedded-in’-thatistheywerenotseatingintothediscs.However,aswitchwasinstalledsothatforeandaftbrakesofeachbogiecouldbeselectedsothat bedding in could be accomplished during the next taxi. The PrimaryNo.1hydraulicswaslostduetoalinebreakatacouplinginADSBayNo.1.

Ammoniafumesinthecockpitwerecausedbycontaminatedmake-upairfromtheengineswhichhadingestedtheoverboardexhaustedammoniafumes.Thisconditioncouldonlyhappenduringtaxiandgroundoperationswheretherewasinsufficientwindtocleartheareaforwardoftheinletsoffumes.Tocorrect theunacceptable condition, aground lockout relaywasinstalledwhichclosedthemake-upairvalveduringgroundoperations.

Thesecond taxi testwasmadeon16Augustwith the firstpass to35knotsindicatedairspeedsatisfactorilycompleted.However,thesecondpasswasabortedduetoahydraulicleakcausedbyarupturedlineatamanifoldfittinginADSBayNo.1.Duringthetaxitestsatlowspeed,thebrakesstillchatteredsobadlythatitcausedthelandinggeardoorstoopenandtheNo.3 enginenozzle to go full open.Thebedding in of thebrake liningswasscheduledtocontinueduringthenexttaxitests.

Thethirdtaxitestswereconductedon24Augustwithtwopassesupto65 knots indicated airspeed satisfactorily completed. However, after thesecond pass a hydraulic leak was found in ADS Bay No. 6 which was

causedbyaprimarypumpvalvemanifoldsealfailure.Itwassubsequentlyfoundthattheleft-handbrakeactuatorwasalsoleaking,whichresultedininstallinganewVitonsealinallbrakeactuators.On25Augustthefourthtaxitestsweresatisfactorilycompetedwithnoproblemsencountered.Twopasses were made; the first up to 86 knots indicated airspeed (75 knotsgroundspeed)andthesecondupto122knotsindicatedairspeed(100knotsground speed). During the second pass, the drag chute was satisfactorilydeployed at 122 knots indicated airspeed and jettisoned at 80 knotsindicatedairspeedwithsubsequentdecelerationaccomplishedbymoderatetoheavybraking.

Lefttoright:ColonelJoeCotton,‘Fitz’Fulton,VanShepardandAlWhite

The fifth and sixth taxi tests were satisfactorily completed on 14September 1964. The fifth taxi test consisted of one pass at 87 knotsindicated airspeed while the sixth consisted of one pass at 97 knotsindicatedairspeed.Afterthesixthtaxitest,theaircraftwasputbackuponjacks,alleightmaingeartyreswerereplacedduetowearandthelandinggear cycled twenty times in preparation for the first flight. In addition,several binding hydraulic valveswere replaced and theNo. 4 andNo. 6engineshadtobereplacedduetoforeignobjectdamage(FOD).

Theextensiveprior-to-firstflighttaxitestswereconductedtoallowthepilottoevaluatethelowandhighspeedcharacteristicsofthenewaircraft.This included radius of turn, steering, braking, intermediate speeddirectionalcontrol,highspeeddirectionalcontrolandnosewheellift-offorlongitudinal control power. It also allowed the pilot to evaluate visibility

and get the feel of the machine, such as establishing reference points,during these critical phases of just before flight. It also allowed thecollection of valuable engineering data. Since these conditions wereevaluated on Air Vehicle No. 1, the No. 2 air vehicle taxi tests werecompletedinoneday;10July1965.

Alfredo‘Fred’JohnAscani(29May1917-28March2010)MajorGeneralandtestpilotoftheUnitedStatesAirForceandwasconsideredfatherofSystemsEngineeringatWrightField.

On21September1964,AirVehicleOnewasdeclaredreadyforitsfirstflight.Asinitiallyplanned,theoneandthree-quarter-hourhopwouldberather spectacular for a maiden flight. Since Plant 42 was in a semi-populatedarea,cautionwouldbeexercisedimmediatelyaftertakeoff–thelanding gear would remain down and the airspeed low. But once theValkyriewasoverEdwardsAFB,theplancalledforretractingthelandinggear and accelerating through the speed of sound at 30,000 feet. If theaircraftwentsupersoniconthefirstflight.NorthAmericanwouldreceivea$250,000bonusfromtheAirForce.

Detailsoftheplansforthetaxi-trialsatPalmdale.

At 05.30 Alvin S ‘Al’ White, North American Chief Test Pilot, andColonelJosephE‘Joe’Cotton,AirForceB-70ChiefTestPilot,beganthepreflight inspection,althoughthegroundcrewhadcheckedtheaircraftsocarefullythattherewaslittlechancethatanythinghadbeenoverlooked.

At06:10,WhiteandCottonclimbedaboardAV1tobeginthepre-flightchecklist.EngineNo.1wasstartedandbroughtuptooperatingtemperature35minuteslater.IntheprocessofstartingthesecondJ93,however,cautionlights indicated a failure in the engine’s cooling loop.Both engineswereshutdown.Afewminuteslater,theproblemwastracedtoatrippedcircuitbreaker.

Theprocessofstartingtheenginesbeganagainat07:14.With132,000poundsoffuelinthetanks,AV1begantaxiingtowardsthePalmdalemainrunway. Taxiing was a delicate affair - the XB-70A had alreadydemonstratedamajorproblemwithbrakingat lowspeedsfor therewasaviolentchatterthatcausedtheXB-70A’sbrakingdistancefromjust5mphto be 400 feet. This had still not been fully solved, thus makingmanoeuvring a tedious affair. During taxiing, the XB-70A also exhibitedanother trait - with the pilots so far in front of the nose wheel, theyexperiencedsomethingofaroller-coasterrideas thecockpitporpoisedupanddownas thenosewheel rodeover the joints in the concrete taxiway.ThiswasmagnifiedbythelongneckoftheValkyrieandsothenickname‘Cecil’-from‘Ceciltheseasickseaserpent’whofeaturedintheBeanyandCecil animated cartoon series created by Bob Clampett - was rapidlyadopted.Thenicknameseemedparticularlyaptandwasusedbymanyofthepeopleinvolvedwiththeprogramme.

AV1taxiesoutsometimeafterthefourthflight.(USAF)

Finally, at 8:24, the Valkyrie was aligned on the runway. Al Whiteadvanced the six throttle levers to themaximumafterburnerposition, andtheXB-70Abeganitstakeoffrun.At193mph,Whiterotatedthelongneckof theXB-70A into the air, establishing a nine degree angle-of-attack forthe wing. At 205 mph and at 4,853 feet down the runway, the 387,620poundsoftheValkyrieliftedintotheskyforthefirsttime.Aspertheflightplan, speedwas held at 310mph and the gear left down for the flight toEdwards.Nounusualhandlingproblemsoccurredduringthistime.

62-0001-AV1-ispreparedforitsfirstflight.Theheightuptothecockpitentrydoorisnoticeable.(NAA)

AV/162-0001isseensecondsintohermaidenflightfromPalmdale.FlownbyAlWhiteandJoeCottonforthefirsttimeon21September1964,the107-minuteflightwastoEdwardsAFB.Of

interestisthattherearofthe‘sixpack’isalmostallbaremetalthiswasnotfullypainteduntilafterthefourthflight.(NAA/USAF)

Numerousphotographshaveappearedovertheyearsclaimingtobeofflightnumberone-andoftentheyarewrong,forthereisalittleknown,buteasily identifiable feature ofAV 1 that can discountmany of these ‘firstflight’ pictures - the lower fuselage around the engines was left in baremetalfinishforthefirstfourflights.

At08:51, theXB-70AwasoverEdwards,and,havingmetupwithallthechaseplanesinvolved,Cottonattemptedtoretractthelandinggearforthe first time. A minute later, waiting for the retraction indicators to go‘green’, one of the chase aircraft called out that the retraction had failed.The right side main gear had stopped midway through the retractionsequence.

The chase aircraft pilot reported that the main landing gear legs hadstopped moving after only completing the first motion - they had onlyrotatedperpendiculartothedirectionofflight.Healsoreportedseeingbluestreaksonthefuselagebehindthelandinggeardoors,andthatsomekindoffluid appeared to be leaking out.A leak in the hydraulic systemwas thesuspected culprit, but inmid-flight, theonly thing todowas to re-extendthelandinggearquicklybeforealossofpressuremadeitimpossibletodoso.Cycledback to the extendedposition, thegear locked itself back intoplace, and theValkyrie continued on her alternate flight plan, proceedingwithsomelowspeedhandlingtests,whichshowedstabilityandcontroltobemorethanacceptable-andwasbetterthantheB-52!

NoComment!(AFFTCHistoryOfficeCollection)

AV1climbsawayfromPalmdaleenroutetoEdwards.(NAA/USAF)

Half an hour later, the number three enginewas showing 108% rpm,andsowasshutdownasaprecaution.WhiteandCottonthenproceededtolineup for landingon the15,000 foot runwayatEdwards.Sitting almost110 feet in front of the main landing gear, combined with the nose-upattituderequiredtolandthebigdeltawing,itwasdifficultforthepilotstojudgetheiraltitudeabovetherunway,ortheactualpointoftouchdown.ItwasnotuntilthetenthflightthatAlWhitestoppedusingthechaseplanesto call out his altitude. Aiming for touchdown 2,000 feet down the longrunway,WhitesmoothlysettheXB-70ontheground.

HowNorthAmericanheadedtheirpressreleaseswithapressure-suitedairmanandtheoutlineoftheValkyrie.

Theendofthemaidenflightof62-0001atEdwardsAFB,showingthefireduringthelandingrollandit’saftermath.Ittookeighthourstorepairthemachinetoapointwhereitcouldbemoved.(all

NAA/USAF)

Immediately troubleset in.AlthoughWhiteandCottoncouldn’tsenseit, apressure surge in thebrake systemhad locked the rearwheelsof theleftsidemaingear,causingafireduringtherollout.Notifiedofthis,WhitelettheValkyriecoasttoastop,using10,800feetofrunway.Oncethefirewasextinguishedtheaircraftremainedontherunwayforovereighthourswhileitwasde-fueledandthelandinggearwasrepaired.ThentheXB-70couldbemoved.

NorthAmericannever received theirquarterofamilliondollarbonusforgoingsupersoniconthefirstflight.

TOWORK–TOTEST

WiththecompletionoftheonlypartiallysuccessfulmaidenflightofAV1itwastimetogetdowntotheseriousbusinessof‘wringingoutthewrinkles’ofthenewdesignandexploringtheenvelopeoftheaircraft.

On5October1964,WhiteandCottontookAV1intotheairagainwiththe full intent of going supersonic. If theywere successful on this flight,NorthAmericanwould receivea$125,000bonus. Ifhowever they failed,NorthAmericanwouldbeassessedpenalties–beginningat$125,000–foreachadditionalflightuntiltheXB-70Abrokethesoundbarrier.

Following takeoff,withachaseaircraftoneachside, the landinggearwas retracted, then lowered, then retractedagainwithoutaproblem.Withthe landing gear up and stowed, theXB-70A climbed to 28,000 feet andacceleratedtoMach0.85(600knots).Thenanewproblemappeared–theNo. 1 utility hydraulic system began losing pressure, andWhite headedbacktoEdwards.Onthefinalapproach,thelandinggearhadtobeloweredusingtheemergencyelectricalsystem.Thetouch-downonthelakebedwasuneventful,andAV1rolled toastopafter10,000feet,despiteoneof themaindragchutes refusing todeploy.Again, therewas tobenobonus forNorthAmerican.

Aweeklater,on12October1964,AV1acceleratedthroughthesoundbarrierforthefirsttime,reachingMach1.11at35,400feetfor15minutesbefore decelerating beneath the sound barrier and breaking back throughseveral times to check transonic stability. Again, one of the drag chutesopenedlateduringlanding,butdidnotseriouslyaffecttherollout.

Thefourthflight,on24October,fulfilledthePhaseOnetestobjectivesofdemonstrating thebasicairworthinessof theaircraft.WhiteandCottonwereagainatthecontrolsforaflightthatlasted1hourand25minuteswithAV1 reachingMach 1.42 at 46,300 feet. For the first time, thewingtipswereloweredtotheirmid-down25-degreeposition.TheXB-70Aremainedsupersonic for 40 minutes, establishing a new record for sustainedsupersonicflight.

AV1undergoingpre-flightcheckspriortohersecondflighton5October1964.Notetheamountofgroundequipmentsurroundingtheaircraft,notmadeanymoretidierbythecollectionofcarsparked

onthesideofthetaxiway.(AFFTCHistoryOfficeCollection)

Afterthesecondflight62-0001startedtoshowsignsofpaint-peeling.(USAF)

TheaircraftreturnedtoPalmdaleattheendofthisflightforaseriesofstructural tests. They would be non-destructive in nature since theprogramme had not built a dedicated structural test airframe, although anumber of ‘test specimens’, had been built, including most of the rearfuselage that was used for wing bending tests, loads in the engine ductregionandfueltankverification.

WhileatPalmdale,engineerspuzzledoverwhysomeofthewhitepaintpeeled off during three of the first four flights. Itwas finally determinedthattoo-thickpaintcausedbyseveralre-paintings–allegedlydoneinorderto impress various VIPs – was being cracked as the Valkyrie flexed inflight,andwas then tornawayby theairstream.During thewinterstayatPlant42,AV1wasstrippedandrepaintedwithasinglethincoatofwhitepaint. A major exterior change was that the bottom fuselage around theengineswasnowpaintedwhiteinsteadofbeingleftnaturaltitaniumfinishasithadbeenforthefirstfourflights.

Structural testingcompletedsatisfactorily,PhaseTwotestingbeganon16February1965,whenAlWhiteandJoeCottontooktheValkyrieonitsfifth flight. For the first time, the wingtips were lowered to the full 65-

degree position, and the manual air inlet control system (AICS) throatrampswerecycled.Thisflightlasted1hourand10minutes,including40minutes at Mach 1.6 and 45,000 feet. Continuing an unhappy trend, thedrag chutes again failed to deploy completely, andAV 1 required 11,100feettorollout.

IthasoftenbeenquotedthatAV1sufferedpaintlossduringearlyflightsduetohavingbeenpaintedtoomanytimestoimpressvisitingVIPswhocametoseethegreatwhitebird...(NorthAmerican

Rockwell)

However,thiscouldhavebeenduetopooradhesionpropertiesofthe‘finishsystem’usedtoreducetheinfraredsignatureoftheaircraft–afinishthatwashighlysecretatthetime.(NorthAmerican

Rockwell)

The sixth flight, on25February1965,marked the first time someoneother than White and Cotton was at the controls. Lieutenant ColonelFitzhugh‘Fitz’Fulton–latertobeNASA’schieftestpilot–flewascopilotwithAlWhite.Butagain,hydraulicleakscuttheflightshort.EngineersatNorth American worked to modify the hydraulic systems to end theconstant leakage problems that had disrupted every flight. These changesand‘fixes’werenevertotallyeffectiveonAV1,butgreatlybenefitedAV2duringitsconstruction.

ThenormalclimbschedulefortheXB-70Aaircraftconsistedofaseriesof accelerations, combined with variations in canard flap and elevondeflections,windshieldrampslopeadjustments,engineair inlet/throatandwingtipgeometrychanges;thelandinggearwascycledsoonaftertakeoff.TheVGwingtipswereloweredtomid-down,or25degrees,anywherefrom400to630knots.SteadyaccelerationfollowedtoMach1.5,wheretheVGwingtipswereloweredtofull-down,or65degrees.AMachnumberof1.5was generally maintained to an altitude of 50,000 feet. Then, if desired,varied rates of accelerations toMach3 at 70,000 feet followed.The bestrecordedtimeto2,000mphand70,000feetwas25minutesafterrotation.

On 4 March, the seventh flight had White and Fulton sustainingsupersonic flight for 60minutes, reaching a top speed ofMach 1.85 and50,200feet.NorthAmerican’sVanShepardmadehisfirstflightasco-pilotduringtheeighthflighton24March1965reachingMach2.14and56,100feet – 40 minutes were spent above Mach 2; another 34 minutes aboveMach1.

The12thflightwason7May1965,withAlWhiteandFitzFultonatthecontrols.TravellingatMach2.60(1,690mph),a‘thump’washeardinthecockpit, followedbyamultitudeofengine-relatedalarmsgoingoff inthecockpit–enginesnumber3,4,5,and6wereshutdownasaprecaution.Asthechaseaircraftcaughtup, theyreportedthat thehorizontalsplitter–theveryapexofthehugedeltawingrightupclosetothefuselage,hadtornaway.Theresultingdebrishadbeensuckedintotheintakesanddoneseveredamage to the engines. For the final approach, the No. 5 engine wasrestartedtoprovidesomethrustfromtherightside,andAV1landedonthelong lakebedwithoutmajor incident.All sixengines,nearlyone-sixthofthe38built,wereconsidereddamagedbeyondrepair.Afterthisflight,thesplitter itself was replaced with a single solid piece of titanium alloy inplaceofthehoneycombunitthathadfailed.

AphotographthatmusthavebeentakenononeofthefirstfourflightsofAV1,foritshowstheunpaintedengineareathatwaslaterpaintedwhite.Thepicturealsoshowsthestandard‘escorts’the

XB-70hadoneveryflight.(USAF)

Theresultsofthehoneycombfailureonthe12thflight.

Below–Lookingupatwhatwasleftofthedamagedhorizontalsplitter.

Right:No.5enginewithdamagedintakevanesandguides.

Belowright:DamagetoenginesNo.1andNo.2canbeseen,alongwiththegashinthefairingbetweenthetwopowerplantscausedbythehorizontalsplitter.(USAF)

Aviewdowntheinletductforengines4,5and6showingthevaneandguidedamage.Thisduct,asbigasasmallroom,alsosustaineddamagetothe‘floor’throughflyingdebris.(USAF)

At thispoint, concernsabout the integrityof thehoneycombbegan tosurface,andthenextfourflightsconcernedthemselveswith‘heatsoaking’theskinforsustainedperiodsof time.For thefirst time, theabilityof theXB-70AtoreachMach3wasbeingseriouslyconsidered.

On 1 July 1965, during the 14th flight, AV 1 recordedMach 2.85 at68,000feetfor10minutes.Onthisflight,severalsheetsofhoneycombskinwere lost fromthe fuselageandupperwingsurface; fortunatelynodebriswas ingested by the engines. Mach 3 was getting closer, but doubtspersisted.

AV2joinstheprogramme.MostofthemajorproblemsthatplaguedAV1werecuredonAV2,whichwas rolledouton29May1965. In addition tohavinga functionalNo.5fueltank,AV2had5-degreesofdihedralonthemainwing,versusthezerodegreesonAV1.Thissmall,but importantvisualdifferenceprovided theobserverwithavaluableidentificationfeaturewhentheaircraft’sserialwasnotvisible.

ThischangewasaresultofwindtunneltestingthatshowedAV1wouldhavepoor roll stabilitywith thewingtips fully lowered.The tradeoffwasthat, at low speedswith thewingtips up,AV 2 suffered from a ‘dihedraleffect’wheresideslipcausedonewingtodrop.Thepilot,sensingthelowwingbutnotspottingthesideslip,wouldusetheelevonstobringthewingbackup–causingmoresideslip,forcingthewingtodroplower.Theonlysolutionwas for the pilots to closelywatch the sideslip indicator. It was

expectedthatanyproductionaircraftwouldcurethisanomalousbehaviourwithchangestothestabilityaugmentationsystem.

Internally, AV 2 featured a revised hydraulic system to reduce theleakingthatcontinuedtotroubleAV1.Techniquestobuildthehoneycombskin had also improved as experience was gained in its manufacture,resultinginastrongermaterialthatwasunlikelytoseparate.

AnautomaticcontrolfortheAICSwasinstalledinplaceofthemanualsystemonthefirstaircraft.Themostvisibleexternaldifferencewasthattheradomeforthenon-existentbomb-navsystemwaspaintedblackonAV2;itwas white on AV 1. This again was a useful identification aid when theserialwasnotvisible.

On17July1965AV2joinedtheflighttestprogram.WithmuchbetterluckthanhadaccompaniedAVl’sfirstflight,thewingtipswerelowered65degrees, and a top speed ofMach 1.41 at an altitude of 42,000 feetwasreached before landing at EdwardsAFB.The second flight ofAV 2wassignificant in that itwas the first time thatAlWhitewasnot thepilot-in-commandofanXB-70A–heandJoeCottonswappedseatson10August1965whileAV2recordedMach1.45at41,000feet.

Initially,AV2wasnotcompletelytrouble-free.Brakechattercontinuedto be a problem during low-speed taxiing; it was suspected that thisstemmed from the lack of return springs for the brake pads. Far moretroubling thoughwas the problems in the automaticAICS system,whichwouldinexplicablyrecycleduringsupersonicflight,causingan‘unstart’.

The normal climb schedule for the XB-70A consisted of a series ofaccelerations,combinedwithvariationsinwingtip,windshield,andairinletgeometry.The landinggearwasretractedearly.Wingtipswere loweredtomid-downanywherefrom400knotsto630knotstoprovideextrastabilityin the transonic region. Steady acceleration to Mach 1.5 at 32,000 feetfollowed,thenthewingtipswereloweredtotheirfulldownposition.Mach1.5 was maintained to about 50,000 feet, and then varying rates ofacceleration were applied until Mach 3 (2,000 mph) at 70,000 feet wasreached.Thebest-recordedtimetoMach3was25minutesfromrotation.

62-0207-AV2-ispreparedforflight.Theblackpaintedareaofthenose‘radome’isnoticeableinthisview.Thetruckintheforegroundprovidedhigh-liftcapabilityforcockpitentry.

FromMach2on,therectangularairinletrampsbegantoclose.Asthespeed increased, theirgeometrychanged toprovide theoptimumpressurerecovery throughaseriesof sequential shocks;beginningwithanobliqueshock from the splitter plate, ending with a terminal shock as the airreached the throat areas. Introducing the initial shockwavewas ‘starting’theinletramps.If theshockwaverefusedtoenter,orpoppedbackoutoftheinlets,itwascalledan‘unstart’condition.

Al White described an unstart at Mach 3 as ‘...sudden and violent,accompanied by a large reduction in engine thrust. The aircraft rolled,pitched,andyawed,accompaniedbyconsiderablebuffeting’.Normallyoneinletunstartedwithabangandas thepilotwas recovering theother inletwouldunstart.SimilarproblemsalsoaffectedtheLockheedBlackbirds–itwas one of the hazards of very high speed flight.While not particularlydangerous, unstarting was one problem facing supersonic transportdesigners. Passengers aboard an SST would not appreciate such anoccurrenceinflightandit tookthejointdesignteamsofAérospatiale,theBritish Aircraft Corporation and Rolls Royce to come up with a viablesolution.

AV2isrolledoutintotheCaliforniansunshineon29May1965.(BothNorthAmericanRockwell)

62-0001alongwiththeTB-58AescortovertheArizonadesert.(USAF)

Therewasanother,potentiallymoreseriousproblem.Sometimes,speedand throat ramp settingswould create a conditionwhere the shockwavewasrightattheboundaryoftheinlet,jumpinginandout.This‘buzz’hadtobe correctedquickly– if it continued formore thana fewminutes thestressescouldcausestructuraldamage.

Despitetheproblems,byitseighthflightAV2hadreachedMach2.34at 57,500 feet. However, Al White’s post-flight report recommendedwaitinguntiltheAICSwasfixedbeforeattemptingaMach3flight.

MeanwhileAV1continued togo faster.Finally, on14October1965,the aircraft recordedMach 3.02 at 70,000 feet. As the aircraft and crewaccelerated through Mach 3 Al White reported ‘There’s that big magicnumber’. For just over two minutes everything appeared fine. Suddenly,WhiteandCottonheardsomethingbehindthem.Althoughnocautionlightshadcomeon,Whitedecidedtodecelerateandletthechaseaircraftcatchuptoseeifanythingwaswrong.ChasesoonreportedthatabouttwofeetoftheleftwingleadingedgewasmissingfromtheValkyrie.Asluckwouldhaveit, the damaged section of thewingwas far enough outboard so that the

debris was not drawn into the engine inlets. So, after 56 weeks and 17flights,AV1hadfinallyreacheditsgoal–butitwouldneverflyatMach3again.Alarmedwiththeongoingskinseparationproblems,andhopingthatmanufacturingimprovementsinAV2wouldfinallysolvetheproblem,theAirForce imposed a strictMach2.5 speed limitationonAV1.However,AV1wasthelargestandheaviestaircrafttohaveeverflownMach3,evenifwasonlyfortwominutes!

AnunusualandstunningphotographtakenfromthebackseatoftheT-38Talonchaseaircraftwithreflectionseverywhere.ItisthoughtthatthisisAV2.(USAF)

Duringits15thflight,on11December1965,AV2reachedMach2.94briefly,butranatMach2.8for20minuteswithoutanyindicationsofskinseparation.Tendayslater,after7minutesaboveMach2.9,theoilpumpforthe No. 4 engine failed. Shutting down the engine, White and CottonheadedbacktoEdwards,whenanovertemperaturecautioncameonfortheNo.6 engine, which was also shut down as well. After landing, it wasdiscovered that, despite the early shut-down, loss of lubrication had

destroyedengineNo.4–nowtheflightprogrammeonlyhad29airworthyengines left. The No.6 engine was removed and sent back to GeneralElectricforrepair.

Inlessthansixmonthsafteritsfirstflight,AV2reachedMach3onits17thflight–coincidentallythesamenumberofflightsthatAV1neededtoreachMach3.AtopspeedofMach3.05(2,010mph)wasrecordedfor3minutes.Thepost-flightinspectionrevealednosignofskindamage.Greatconcernwasstillbeingexpressedaboutthelikelihoodofmorehoneycombseparation, and AV 2 twice more went beyond Mach 3 for just a fewminutes before sustaining 2,000 mph at 73,000 feet for fifteen minutesduringher22ndflighton17February1966.

AirVehicleTwoatEdwardsAFB.Thesleeknessofthedesign,andthedistancethecockpitisaheadofthenosegearisnoticeable.(USAF)

FlightTestrecordingToday, recording of flight data during any flight would all be done onmicrochips.BackinthetimeoftheXB-70theFlightTestInstrumentationSystemfortheXB-70airvehiclewasveryadvancedforitstime,butwouldbe looked upon as being archaic today. It was developed to provide thecapabilityofobtainingdata required toestablish safetyor flight limits, toevaluate sub-system functional operations, and to define gross problemareas within the realm of the various flight test tasks. The airborneinstrumentationsystemalsocontainedprovisionsforobtainingSupersonicTransport(SST)dataandsupplementalcockpitinstrumentationforspecialflight monitoring requirements. The primary data acquisition media wasmagnetic tape recorded in both digital and analogue formats. In addition,

selectedparameterswere telemeteredto theGroundStationanddisplayedinrealtimeonchartrecordersconcurrentwiththeflight.

The high capacity airborne instrumentation system developed for theflight test programme, provided the capability of subsystem test sharingduring each flight of the XB-70’s. This provided an equivalent test hourtotal five times actual flight test hours plus the invaluable capability of‘looking’ at all sub-systems for gross problems during the first phase offlighttesting.This‘grosslook’atallsubsystemsprovidedearlydetectionofproblem areas which resulted in a timely progression of the flight testprogramme.

Six basic types of parameters were recorded by the airborneinstrumentation system. They were miscellaneous, acceleration, position,temperature, strain, and pressure. To acquire the parameter data, threesensor or transducer installations were employed. The conventional ornormalapproachwaswherethetransducerwasaddedat,ornear,thepointof measurement. The second type was where an air vehicle sub-systemconfigurationhadanelectricallyisolatedsensorincorporatedaspartofthebasicconfigurationandwasfurnishedasanintegralpartofthatsub-system.Thisavoidedtherequirementformakingadirectelectricalconnectionandaffordedmaximum isolationandsafety.The third typeof installationwasthedirectpick-offmethodandappliedonlytothemeasurementofelectricalquantities, such as, voltage, current, frequency or to parameters alreadyexistinginelectricalform.

In thecourseofbuildingup theoveralldataacquisitionsystemitwasnecessary to meet requirements for data sensors which were capable ofoperation in high temperature and vibration environments. Much waspurchasedfromoutsidevendors,butsensorsforthemeasurementoflinearpositions,rotarypositions,airflowdirections,andhighvibrationhydraulicpressureswerenotavailable.Theseitems,therefore,hadtobedesignedanddeveloped within the Instrumentation Group. High temperature bondedstrain gauge and variable reluctance techniques were applied in theconstructionofthesedevices.

The instrumentation package was the heart of the airborne dataacquisitionsystem.Thiswasaspeciallydesignedpackagewhichcouldbelowered out of or raised into the air vehicle forward weapons bay. Theequipment section was divided into four areas, three of which werecompartmented for installation of modular chassis employing rack and

panelconnectors.Thefourthareacontainedthetaperecordingequipment,the programme panels, circuit breakers, operational controls and displaysforperformingpre-flightandcheckoutoperations.Coolingair, inmeteredamounts, was forced through each chassis from a self-containedenvironmental control systemwhichemployed liquidnitrogen forcoolingand pressurization. Temperature was regulated between limits of 40 andl60° F. Pressure was maintained so that it was never less than thatcorrespondingto8000feetaltitude.Environmentalcontrolprovisionsweredual,providingback-upoperationintheeventofanin-flightfailureofthesystem.The instrumentation packagewas entirely independent of any airvehiclesystemwiththeexceptionofelectricalpower.

Thedigitalsystemandanaloguesystemweretheprimarymediaofdataacquisition, and were some of the earliest in use for this type of work.Althoughtechnicalinnature,thispioneeringsystemdeservesdescription.

TheinstrumentationpackageasinstalledintheweaponsbaysofAV1.TheweaponsbaysonboththeXB-70swereinoperableassuch,fortheycouldnotbeopenedinflight,andcarriednoweapons

suspensionracks.Thepackagecouldbeloweredformaintenance.(AFFTCHistoryOfficeCollection)

Thedigitalsystemprovidedfortherecordingofaround800channelsofquasistatic data with a maximum frequency response of 20 cycles persecondforselectedchannels.Awidevarietyofparameterswere recordedand with the exception of thermocouples, all data channels wereindividuallysignalconditioned.Thefollowingsub-paragraphsdescribethemajorfunctionsofthedigitalsystem.

Multiplexing:aschemeoftimemultiplexingwasemployedtosample,digitize, and record each data channel in accordance with a prescribedrepetitive pattern. Fifty channels ofmaster commutation received signals

sequentiallyfromtwopredigitizeddatachannelsand48sub-commutators.Filtering:tolimitthesignalfrequencyspectrumtothatwhichcouldbe

recoveredfromtherecordeddataatthedigitizingratesprovided,precededthesignaloperation.

Commutation:wasaccomplished,at low level,by solid state switcheswhichswitchedbothsidesof thesignal lines.Theswitchingrate foreachmaster channelwas 400 times per secondwhich set the total system andsampling rate at 20,000 times per second. Switch and system sequencingcommandswerederivedbydividingdownfromamastercrystalcontrolledclocking oscillator.A system time codewhichwas recorded as data,wasalsogenerated from this source.Switchingwas followedbyamplificationtobringthesignaltothe+/-3voltlevelrequiredbytheanaloguetodigitalconverter.Fivesequentiallygatedamplifiersperformedthisfunction.

FromtheFinalReportcomesthisdiagramaticrepresentationoftheAirborneInstrumentationSystem.(NorthAmericanRockwell)

Withlandinggearandflapsdown,AV2turnsontofinalapproachtothemainrunwayatEdwardsAFB.(USAF)

Digitizing:digitizingwascompletedin15micro-secondsatarepetitionrateof20,000timespersecond.Thedigitalresolutionprovidedwas1partin1024,correspondingtoconversioninto10binarybits.Theconverterwasself-clocking, but received its command to digitize from the systemprogrammer.

Recording; recordingof thedigitizedoutputwas inparallelbinarybitformatonl6track1inchmagnetictape.Thoughdatawordswerenormally10bits in length, the recordingsystemwascapableofacceptingup to20wordsof 13bit length as derived from shaft encoders or other externallygenerateddigitalinputs.Theselongerwordswererecordedonthetapebygatingthemintotherecorderatpresettimesinthedatasamplingsequence.Additionalbitswerealsorecordedontracks,notusedfordata, toprovidereadout clocking and to indicate lateral parity, commutation frames andcycles,andsystemoperationalmodes.Thepackingdensityonthemagnetictape was 667 words per linear inch with the tape recording speed of 30inches per second. Two digital tape machines were employed for dataacquisitioning. The switch over from the first to the second recorderoccurred automaticallywhen tape on the firstmachinewas exhausted.Atotal of between 48 and 96 minutes of recording time was availabledependingonthethicknessofthetapeused;however,duringtheflighttestprogramme a thin tape was used so that the recording time wasapproximately96minutes.

The analogue system, which provided for the acquisition of highfrequencydata,employedfrequencymultiplexingtorecordupto144datachannelsinbanksofupto12channelsperdatatrackontoal4track1inchmagnetic tape. Track 13was used for tape speed servo control only, andtrackl4wasusedforcorrelationdataonly.

Recording:oneanaloguetaperecorderwasusedwitharecordingtapespeed of 15 inches per second for acquisitioning the higher frequencyparametersoftheairbornesystem.Atthistapespeedandwiththintape,90minutesofrecordingtimewasprovided.

Telemetry: the real time display of 36 selected parameters, viatelemetry, for the full duration of the flight, proved useful inmonitoringflutter and certain other important parameters. Such monitoring made itpossibletofollowpredictedversusactualflightconditionstoguardagainst

exceeding given limitations. It also permitted extensions of the flightenvelope during the course of the test. The composite data signalsappearing on analogue tape tracks 1, 2, and 3 were telemetered to thegroundonthreeUHFradiolinksoperatingon228.2,250.7,and259.7Mc.These datawere displayed on chart recorders, and provided a permanentrecordoftheflight.Correlationwiththein-flightrecordswasprovidedbytheanaloguetimecodeformat,anddatarecordstartandstopsignals.

AV1restsbetweentests,withallthestaticportspluggedandtow-tugattached.TheobviouswayoftellingAV1andAV2apartwasthatAV1didnothavethelowerradomeareapaintedblack.

VGHRecorder: the NASAVGH recorder provided a time history ofairspeed, altitude, and normal acceleration. Normal acceleration wasmeasuredatboththecentreofgravityandthepilot’sstation.Thedatawererecordedona200footrollof70mmphotographicpaperwhichadvancedattherateoftwoandahalffeetperhourinaremovablerecordingdrum,

CockpitCamera:al6mmpulse-operatedcamera, installedbetweenthepilot’s and Co-Pilot’s capsules, was focused on the cockpit instrumentpanel. The field of view included all of the pilot’s engine and flightinstruments.Thecamerawaspulsedattwoframespersecond,andrecordedonlyduringtheinstrumentationrecordingperiod.

TheconvertedschoolbusseeninboththesephotographswasNorthAmericanAviation’s‘MobileCommandCenter’usedtosupporttheXB-70programme.(bothUSAF)

Pilot’svoicerecorder:acompact,quicklyremovabletaperecorderwasinstalled in the cabin equipment compartment to record flight comments.TherecorderwasalsowiredintoAIC-18AudioBustorecordallinter-comconversation,andtransmittedorreceivedradiocommunications.Atotaloffourandahalfhoursofrecordingtimewasavailableatarecorderspeedoffifteen-sixteenthsofaninchpersecond.

Landinggearcamera:a16mmcamerawaslocatedineachmainlandinggearwelltorecordthebehaviourofthegearatthetouchdownpoint.Thesecamerasoperatedat100framespersecondfora40secondduration.

Sensitive Airspeed and Altitude Recorder: a NASA recorder of theVGH typewas used to record sensitive airspeed and altitude. These datawererecordedon70mmfilmoperatingattherateoftwoandahalffeetperhour.

Landingontip-toeOn7March1966the37thflightofAV1showedthetypeofadversitythatcouldbeovercomebyapairofexperiencedtestpilots.VanShepardwasthepilotandJoeCottonwascopilot.Halfwaythroughtheplannedflight,bothhydraulicsystemsbegantofail.ShepardquicklybroughttheValkyriehomeasCottonextendedthelandinggear.Nogreenindicatorscameon,andthatwassoonfollowedbyacall fromthechaseaircraft that therewastroublewithbothsetsofmaingear.Ontheleftside,thegearhadnotfullyloweredbefore rotating to meet the direction of travel, leaving the rear wheelshigher,ratherthanlower,thanthefrontsetofwheels.

Therightsidegearwasinworseshapeasithadn’tloweredatallbeforerotating.Evenmorealarming,ithadn’trotatedcompletelyinlinewiththedirectionoftravel,althoughitwasclose.Neitherthebackuporemergency

systemcorrected theproblem.Afterwhatmusthaveseemedlikehours inthecockpit,engineersonthegroundcalleduptothepilotswiththeirplan.Shepardwould land theValkyrie on the dry lake bed, so therewould beplenty of room.The engineers believed that, on touchdown, the left gearwould level itselfout, theweightof theXB-70A forcing thegear into itsnormalposition.Asfortherightgear–beingbehindthecentrelineofthemainstrut,itwasunlikelytolevelout,buthopefullythelandingwouldatleastcausethegeartofinishswingingintothedirectionoftravel,andthewingtipwouldstillcleartheground,althoughtherightsidewouldbemuchlowerthantheleft.

VanShepardfinallybringsAV1toastoponthelakebedatEdwardsfollowinghydraulicproblems.Thetrackacrossthelakebed–andthecloudsofdust–arenoticeable.(USAF)

Landingontip-toe!7March1966andAV1isbroughtinforaverygentlelandingfollowinghydraulicproblems.Thepathtakenbytheaircraftasitswungcanbeclearlyseen.(USAF)

AV2atEdwardsAFB.Thispictureshowstheheightandcomplexityofthecrewboardingladder.Whatisnotsoclearisjusthowsmallthecrewentrydoorwas!(USAF)

VanShepard setAV1downon the lakebed, andeachmaingeardidwhat the engineers expected. The aircraft was down and rolling, but itwanted to turn sharply to the right – threatening to ground loop, which,although probably not fatal to the pilots, would probably destroy theaircraft.SoShepardkeptapplyingpowertotheNo.6enginetohelpkeeptheXB-70Asomethinglikestraight.

Afterrollingalmostthreemilesacrossthelakebed,theXB-70Acametoastop,havingswungoverhalfamiletotherightandturned110degrees.

Onlythesizeofthelakebedmadethislandingpossible.Thedamage,suchasitwas,wasquicklyrepairedandAV1returnedto

flight on 22 March piloted by Cotton and Shepard on a 2 hour and 11minuteflightthatonlyreachedMach0.97at32,000feet.

TheonlytimeanXB-70AwouldtravelanywhereotherthanEdwardsorPalmdalewason24March1966whenFultonandWhitetookAV2totheairshow atCarswellAFB,Texas.TheValkyrie spent only 13minutes atMach2.71beforeslowingdown,endingupat6,000feetoverCarswelljust59minutesaftertakeoff.Forthenexthalfhour,AV2thunderedaroundtheskiesofTexasbeforelanding.Thereturnflighttwodayslaterwastheonlyflight during the entire programme where performance data was notrecorded,asCottonandWhiteflewbackatsubsonicspeeds,takingalittleoverthreehourstoreturntoEdwardsAFB.

Threeimagesfromacontactstripshowingthetake-offinthepredawnlightwithfullafterburnerofFlight54–the22ndflightofAV2.(USAF)

62-0001comesintolandatEdwardsAFB,watchedbythemandatoryrescuehelicopterhoveringinthedistance.(USAF)

ItwasnotunusualfortheXB-70Atoexperienceengineunstartsduringthe testprogramme.For instance,on12April1966AV2wasonahigh-speedflightthathadbeenscheduledtoflyatMach3for30minutes,butAl

WhiteandJoeCottondecidedtocutthehigh-speedrunshortafteraninletunstart.Theinternalshockwavemovedforwardfromitsoptimumpositionwhile the flightcrewwasexperimentingwith themanualverniercontrolsfor ‘fine tuning’ the engine inlets to achievemaximumperformance.Theunstartwasaggravatedbyaturnmanoeuvre–turningalwaysaffectedinletairflow, but was usually compensated for by the automatic inlet controlsystem.

Thetwoflight-testvehiclesinoneofthehangarsatEdwardsAFB.Thecut-outsintheendwallweretolettheruddersthrough.(USAF)

During the 20-minutes spent at Mach 3.08 and 72,800 feet, themaximumfree-stream temperature reached624°Fat stagnationpointsonthe wing and inlet leading edges. The highest previous free-streamtemperaturehadbeen610°Fduringa16-minuteMach3flighton8April.The higher temperature on this flight was attributed to atmosphericconditionsandnotthedurationoftheflight.

The‘Paperclip’FlightNottooutdone,AV2alsoexperiencedalandinggearproblem–thistimeon30April1966the37thflight.Shortlyaftertakeoff,Cottonretractedthelandinggear.However,ashort-circuitinthelandinggearretractionsystempermittedwindforcestoblowthenosegearbackintothepartially-retractedgearwell door, slashing the tires.An attempt to lower the gear using thenormalhydraulicsystemfailed.Tryingthebackupelectricalsystem,Cottonhearda‘pop’asthatsystemwentdead.

WhitefirstbroughttheXB-70Aaroundforatouch-and-go,hopingthatahardimpactonthemaingearwouldknockthenosegearlooseandletitfalltotheextendedposition.Evenafterasecondtry,however,thenosegearremained jammed. At this point, bailing out and losing the aircraft was

quicklybecomingtheonlyoption.Buttherewasfueltoburn,soWhiteandCottoncircledaroundEdwards

while engineers on the ground attempted to sort things out and come upwith a solution.Aftermore than two hours the problemwith the backupsystemwastraced,sotheyhoped,toacircuitbreaker.NowallCottonhadtodowasfindawaytoshortcircuittheunit.Ofcourse,theValkyriehadnoonboardtoolkit–thatwouldhavemadethingstoosimple.ButCottonhadbroughtalonghisbriefcasewithhisvariousnotesandplans,andopeningit,he found a binder-type paperclip. Straightening out the paperclip, thengraspingthemiddleof itwitha leatherglove.Cottoncarefullyreachedinandshortcircuitedthebreaker.Itdidthetrick.

Neitherupnordown.ThenosegearofAV2duringits37thflight.Ittookapapercliptoresolvetheproblem.(USAF)

AV2comestoahaltonthemainrunwayatEdwardsAFBafterthe‘paperclip’flight.

Firetruckssprayfoamoverthemainwheelunitsafterthreeofthefourbrakeassembliesstayedlockedon.

Theaftermath;foursetsofruinedtyresandwheels,withplentyoffoamtobeclearedfromtherunway.(USAF)

TwoviewstakenoutinthedesertatEdwards.AV1ismovedbyagroundtug.Thishead-onviewoftheValkyriewasandstilltothisdayisalwaysdramatic.

However, themalfunctionalsocausedhydraulicpressuretoremainonthree of the four main wheel brakes, which were thus locked when theaircraftlandedat173knots.FirefightersatEdwardspreventedanyseriousdamagetotheaircraft,whichflewagainalittleovertwoweekslater.

On19Mayduringflightnumber39,AV2flewatMach3.06at72,500feet for 33minutes. In just 91minutes, theValkyrie traveled over 2,400miles – an average speed of more than 1,500 miles per hour, includingtakeoffandlanding.Finally,Aallremainingconcernsaboutskinseparationwerelaidtorest.TheValkyriecouldnowcertainlylayclaimtobeingatrueMach3cruiser.

BothmachinesonthegroundatEdwards.Sadly,theynevertooktotheairtogether–imaginewhataformationshotthatwouldhavemade!(bothUSAF)

Atrulystunningpictureof62-0207inflightwiththewingtipsinthefulldownposition.(USAF)

ThreedayslaterAV2thrilledthespectatorsat theArmedForcesDayshowatEdwards,includingacoupleofsupersonicpassesoverthecrowd.Test data on stability and control issueswere recorded during the 2-hourand22-minuteflightthatreachedMach1.51and36,500feet.

With all systems tested, theXB-70Aprepared tomove into Part 2 ofPhaseTwotestprogram,whereNASAwouldbecomemuchmoreinvolved,and extensive sonic boom and handling tests would begin. New pilotswould join the programme, including NASA chief test pilot Joseph A.Walker,whohadjustcomefromtheX-15programme.NotonlydidWalkerhavean‘astronaut’rating(giventoAirForcepilotswhoflewhigher than50milesaltitude),hehadflowntheX-15beyondMach6(4,100mph) inlevelflight.Mach3wouldseemslow.AlsojoiningtheprogrammewasAirForceMajorCarlCross.At thesametime,bothAlWhiteandJoeCottonbegantograduallyeaseoutoftheprogramme,withCottongoingontotestother aircraft for the Air Force, andWhite to work on other projects atNorthAmerican.

AV 2 was refitted with additional instrumentation and data recordingequipment–morethanathousandsensors,recordingdevicesandtelemetryequipmentwereinstalled.Theseinstrumentswouldgiveabetter lookatanumberofphenomenathatcouldn’tbe thoroughly tested inawind tunnelincluding body flex, flutter, and pressure distributions.At the same time,NASA began setting up a large number of ground sensors to preciselymeasuretheeffectofsonicbooms.

Buttragedyawaited.

THEDEMISEOFAV2

Like all accidents, it only happened as a coming together of a chain ofeventsthat,ifthechainhadbeenbrokenatanystagecouldhavesoeasilynever occurred.GeneralElectric started theball rolling for this particularphotographicmission sometime inmid-Mayof 1966,whenGEchief testpilotJohnMFritzapproachedaseniorrepresentativeofNorthAmericanattheEdwardsAFBFlightTestCenter.

FritzwasaskedbyGeneralElectrictoseewhetheritwouldbepossibleto arrange for in-flight photos of the XB-70A in formation with othersupersonic aircraft using General Electric engines. The North Americanrepresentativesaiditmightbeworkedout,dependingontheavailabilityoftheXB-70.

John Fritz then contacted Colonel Joe Cotton. He agreed to theinclusionofthephotosessionattheendofatestflightaslongasitdidnotinterfereandiflargedemandswerenotmadeontheAirForceFlightTestCenter(AFFTC).ColonelCottonhadpermittedNorthAmericantotakein-flightphotosoftheSabrelinerandtheXB-70Aonanon-interferencebasis.HefeltconsiderationshouldbegiventoGeneralElectricsrequest.HealsofeltthatGeneralElectricrespondedpositivelytotheflighttestprogramme.

On2June1966,ColonelCottonrequestedandreceivedapprovalfortheflight from his supervisor, Colonel Cate, the deputy for Systems Test,AFFTC.ColonelCotton:

‘The main thing here, when I realized we were going to have aformation,was I didn’t think itwas appropriate to see a five- or six-shipformation someplace without folks here at home knowing it. I felt it wasimportant to discuss it with the boss and tell him it was a request forGeneralElectricandtopointourthatwehaddoneitbefore,andseewhathethoughtaboutitandgethisguidanceonit’.

JoeCotton(left)andAlWhiteafteranearlierValkyrieflight.NotetheXB-70A‘patch’oneachlightsuit.

No further approvalwas sought or secured, except for the briefing ofColonelCatebyColonelCottonon thedetails.Onceadecisionhadbeenreached, John Fritz started the arrangements for a number of aircraft toparticipateintheflight.HewantedoneoftheXB-70s,andanAFFTCT-38was scheduled to participate in the flight as a chase aircraft. F-104N(N813NA) supplied byNASA for the photomission by JoeWalker,whowas the chief research pilot for NASA at Edwards. The request for thisaircraftbyJohnFritzwasbackedbyColonelCottoneventhoughitwasnotneededforchaseflight.TheflightwasscheduledbyJoeWalkerasachaseoperation,whichwasunderhisauthorityatNASA(althoughhissuperiorsdid not know of the photomission). Fitz also requested a USNavy F-4PhantomfromPointMuguNavalAirStation,California.ThiswassecuredbyJohnFritzwithCommanderJeromeSkyrud,headofAir-to-AirWeaponsBranch,NavalMissileCenterwithEJBlackintheback.ItwasapprovedbytheoperationscoordinationofficerasaroutinetrainingflightinsupportofwhatwasassumedtobeanapprovedAirForcemission.TherewasalsoanF-5 -Air Force-owned, but bailed toGeneralElectric under unrelatedengine component improvementprogrammes. In the technical sense therewasarequirementthatallflightsofbailedaircraftmustbeapproved.Thiswas complied with, but the F-5 did not perform the engine airstartevaluations(the‘official’reasonforitsinclusion)asstatedbyJohnFritzinthedocumentationforthisflight.

John Fritz also attempted to arrange for an Air Force B-58, but was

unsuccessful.He also unsuccessfully tried to arrange forAir Force photocoverage,soacivilianGatesLearjetflownbyHClayLaceywascontractedbyGeneralElectrictophotographtheformation.

TheXB-70A had a reason to be in the air alongwith the T-38 asidefrom the photo session. The F-104N was also considered to be ofimportancesinceJoeWalkerhadflownchaseontheXB-70AanumberoftimesandwastrainingtobeaXB-70Apilot.Hisfirstfamiliarizationflightwasslatedfor10June.

Thephotosessionwasofficiallyaddedtotheresearchflighton2June1966. It was tagged to the end of an airspeed calibration run and afamiliarizationflightforMajorCarlCross.On7Juneathirdobjectivewasaddedtothelist:asonicboomrunfortheSSTprogramme.Intheofficialpaperworkforpreflightreports,onlythesethreemissionswerementioned.

62-0207ispreparedforanotherflightfromEdwardsAFB.(USAF)

Apreflight briefingwas held on 7 June.NorthAmerican handled thetechnical end of the flight while John Fritz handled the photographicsession.A ‘loosevee’ formation thatwasgoing tobe ledby theXB-70Awas proposed rather than a close formation. The F-104was assigned theinboard position and flownby JoeWalker fromNASA.Thiswas off theright wing of the XB-70A. Commander Jerome Skyrud in the F-4 wasgiventheinboardpositionontheleftside.JohnFritzwasassignedtherightoutboardpositioninanotherF-5,andCaptainPeteHoag,intheAirForceT-38,wasintheleftoutboardposition,withColonelCottonintherearseat.TheLearjetwasoutoftheformation.

By all accounts, therewere no specific separation distances discussedand no formation commander assigned, although it seems everyoneassumedthatColonelCottonwasincharge.

Threepilots from theproposed flightwerenotpresentat thebriefing:

AlWhite, who assumed command as XB-70A pilot on June 7when theoriginalpilothad todropoutforanotherflight;CommanderSkyrud,whokeptincontactwithJohnFritzviatelephone;andH.ClayLacy,whowasthe Learjet pilot briefed by John Fritz before takeoff on June 8. On theLearjet, there was a General Electric test pilot who was familiar withEdwardsAFBproceduresandhadattendedthepreflightbriefing.

JohnMcCollum, the director of research vehicles for the aeronauticalsystems division and who served as the XB-70A system programmedirectorwas also involved.At the time, hewasvisitingEdwardsAFB todiscussthenextphaseoftheXB-70AtestprogrammewiththeTestCenter,NASA,andcontractorpersonnel.On7June,hehelpedintheschedulingofthesonicboomrunandwasinvitedtoattendthepreflightbriefing.Hewasthehighest-rankingAirForceofficialatthebriefingandheknewaboutthephotographicaspecttothemission.Sincehedidnotobject,itseemedthatthis was taken as his unexpressed consent. If he did object, the missionwouldnothavebeenabletogoon,asitwaswithinhisjurisdictiontotaketheXB-70Aoutoftheflight.

Mommahenandherchicks.ClosesttothecameraisJohnFitz,inanF-5.ThenthereisCommanderJeromeSkyrudinandUSNavyF-4.XB-7062-0207,thenJoeWalkerintheNASAF-104.Outboard

rightisCaptPeterHoagandColonelCottoninanAirForceT-38.(USAF)

62-0307fliesinformationwiththeotheraircraft.Asfarasisknown,oncetheformationwascreated,allremainedinthesamerelativepositionsuntilafterthecollision.

XB-70A AV 2 took off at approximately 07:15 to run the airspeedcalibrationtests.Asusual,therewasachaseaircraftfollowingit-thistimeaT-38.WhentheXB-70Astartedtoclimbforasonicboomrun,theT-38hadtolandtorefuel;anotherT-38intheareacheckedtheXB-70Atomakesurethatthecoolingdoorswereclosed.Thesonicboomrunwascompletedby 08:30 and all indications suggest that the rendezvous portion of themissionwascompletedatabout08:45.Therewereclouds in thearea thatmade a change in altitude necessary - from the prescribed 20,000 feet to25,000feet.Locationanddirectionwerealsochangedfromnorth-southtoeast-west,thelatterresultinginamuchshorterfightpath.

Itisclearfromthebackgrounds,thattheyweresearchingtofindasuitablebackdroptoshowofftheformationtoitsbestadvantage.(bothUSAF)

Thisimagehasappearedinnumerabletimes,butgoingbacktotheoriginalsourceshowsittoitsbestadvantagewithlesscropping.(USAF)

Recorded radio ‘chatter’was to hint atwhatwas happening.XB-70ApilotAlWhite:‘Roger,I’mgoingtohavetoclimbslightlyorI’mgoingtoloseeverybodyintheclouds’.WhitealsohadrestrictedvisionfromtheXB-70A-especiallytotherearandatonestagewasheardtoask‘HowmanyairplaneshaveIgotwithme?’

JoeWalkerreplied:‘YougottwonowandthereshouldbeaT-38andanF-5plusthephotoLearjet’

Fritz: ‘I’m joiningnow.AT-38 is on theway.Would it be possible tomakealeft-handturnhereforalittlebitandletthisLearjetcatchup?”

White:‘Oh,okay.I’llhavetogoaroundthiscloudthinghere.’ItseemsthatthecloudswereacontinuousproblemandWhitespokeof

them several times as he moved above 25.000 feet, still surrounded bycumulus but straining to let the photo plane catch up.Once he said: ‘MyproblemisIcan’tgoanyhigher...I’mafraidI’lllosethemifIgo...I’mjustmillingaroundinthesethings.That’swhyIwantedtogoouteast.’

Walker:‘Ithinkyou‘rerightAl.Overeastisalotbetterandyoucanstaylower.’

Thesituationimproved.TheXB-70Adroppeddownandslowedto300knots. Then Fritz spoke up from his position just outboard of Walker:‘...Yougotallyourchickens.’

White:“Great.Whatdowewantthemtodo?Justflylikethisandgetsomepictures...okay?”

Noproblemswere reportedwith the formationand it continuedon its

way.Ataround09:00,anAirForcephotoaircraftonareturnfromanothermissionhad100feetofunexpendedfilm.Thatflightaskedforandreceivedpermission to film the formation in progress. At 09:15, the Learjet wasquestionedaboutadditionaltime,sincethealready-planned-for30minuteshadelapsed.TheLearjet requestedanadditional10-15minutes.TheDataRecord transcript tells thestory: ‘TwoZeroSeven’ is thecall-sign for theValkyrie:

Theformationkeepsstationwhilethecameraaircraftcirclesit(USAF)

09:20:02:

DATACONTROL:Ah, yes, this isDataControl. Is tank eightfeedingnow?AV 2 (Cross): Affirmative tank eight is feeding properly now.DATACONTROL:Rog.

09:21:24

INTERPHONE(Cross):Theymusthavehad thatLearjet fulloffilmorthey’dbeoutofbusinessbynow.AV2 (White):Yes—Hewas sitting therebut he’s upherenow.Thisholeisgettingsmallerandsmallertoo.

09:22:47 #813 (Walker):Wemust be helping the cumulus activity alongwithallthishotair.

09:24:48RAPCON:Twozeroseven.Traffic.Twozeromileseastofyourposition,orbitingThreeSisterstwofourzero,twosevenzero.AV2(White):Roger,Thankyou.

Aclose-upofJoeWalker’sF-104.TheValkyrie’swingtipisjustvisible.(USAF)

09:25:05AV 2 (White):We got a contrail out there—but, I don’t ah, itlookslikehe’shigherthanthat.INTERPHONE(Cross):Probably—

09:25:23#601(Cotton):LearjetsLear—Another fourminutes theLearjetsaid.AV2(White):Thanks,Joe.

09:25:42DATACONTROL:Twozeroseven,theLearjetsaysaboutthreemoreminutes.AV-2:OK,Zeke.RAPCON:Twozeroseven,he’soffyourleftwingnowah,belowtheclouds.

09:26:06 AV2(White):Roger,thankyou.RAPCON:The B-58’s speed run is now one five miles east ofyourpositionwestboundthreezerozeroorabove.AV2(White):Ihavehim,thankyou.

09:26:26??:Atthistimetherewasonecarrierburstfollowedbyalongercarrier, of one secondmaximum duration, sounding like a livemicrophoneinanopencockpit.

09:26:28

??: There were two or more carriers on the frequency withresultantsignalclash,followedby#601(Hoag):Mid-air,mid-air,standbyfor—#601 (Cotton):Yougot theverticals, this isCotton, yougot theverticals—came off left and right. We’re staying with ya, nosweat,nowyou’reholdinggood,Al.

TheNASAF-104collidedwith theXB-70.ThefirstcontactwaswiththelefthorizontalstabilizerandthecantedrightwingtipoftheXB-70.TheF-104thenpitchedup,rolledtotheleft,andhittherightleadingedgeoftheXB-70’swing.TheF-104continued its roll inverted into theXB-70’s toprightverticalstabilizerandtookthetopoff the leftverticalstabilizer.TheF-104wascutjustaftofthecockpit,itsnosehittheXB-70’sleftwing,andthefuselageoftheF-104wentstreakingaftinflames.

09:26:40

#601 (Hoag): JoeWalker ran into him and I think he’s had it.(Cotton):The B-70 went upside down, it’s rolling now, the leftwing—#601(Hoag):Bailout,bailout,bailout—#601(Cotton):Bailout,bailout,bailout.

09:27:09

#601(Cotton):OK,theB-70isspinningtotheright—#601(Hoag):Somethingcameout,itlookslike—#601(Cotton):Lookslikeacapsulecameout.It’sspinningtotheright,thenoseisslightlydown.

09:27:23#601(Hoag):Nochute—#601(Cotton):...seenochuteyet.Themaingearisdown,thenosegearisup.

09:27:28 #601(Hoag):Chute,chute,goodchute.

09:27:28#601(Cotton):There’sachute,there’sacapsule(pause).There’sonechute.#601(Hoag):B-70wingupheretoourright.

09:28:02

#601 (Cotton): The B-70 wing is to our right. We’re at fifteenthousand.TheB-70isgoingdown.Iseeonechute,onecapsule.#601(Hoag):Theleftone.#601(Cotton):Theairplanesinaflatspin.Theairplaneisstableina flat spin slightly nosedown.Most of the leftwing is gone.Got several pieces around us. There’s a burning piece to thenorthwest.Theairplaneisflat.We’restayingclearofthecapsule.

Momentsafterthecollision,JoeWalker’sF-104dropsawaystreamingflames.TheXB-70Acontinuestofly,butascanbeseen,bothverticalshavebeenrippedaway...(USAF)

...afewsecondslatertheStarfightercontinuestoburnandbreakupastheformationstartstoopenuptogivetheXB-70Asomespace.(USAF)

As Al White said afterwards: “I heard a good loud thump - anexplosion-andIheardsomebodyyell‘Mid-air’Butwithallthatlengthandmassbehindme,Ididn’tknowitwasus.Myimmediateimpressionwasthat

two other planes had collided. Even when I heard Cotton call about averticalbeinggone,Istillwasn’tsureitwasus.IfIhadheardtheplural.I’dhaveunderstood.”

TheXB-70Awastheonlyplaneintheskywithtwoverticalfins.Cotton,knowingtheplanewasdoneforbuthopingforastableejection

condition, called his encouragement toWhite andMajorCross. Then theXB-70Aabruptlysurrenderedtoitswounds.

AlWhiteagain:Theairplaneyawedabruptlyandveryviolentlytotheright. It was so violent I thought the nose would break off. Then it wasupsidedownandnosedown,andthenrightsideupandnoseup.Itdidthistwiceandthesecondtimearoundabigpieceoftheleftwingbrokeoff.

These were unstabilized rolls and the G forces were fierce. It wasprobably theGs that finally tore thewingoff after it hadbeenweakenedwhenWalkerfellonit.Theforceonmewasviolent,throwingmeaheadandtotheleft.Icouldn’tmoveagainsttheGs.Butthenitsettledintoaflatspin.Thisgave itamoreor less fixedaxis somewherebackalong the fuselageanditwasmorestablebutoutofcontrol,ofcourse.Centrifugalforcewasstillshovingmeforward,butatleastIcouldmovealittle.

When it nosed up out of the second tumble, I began trying toencapsulate’

To encapsulate and eject from an XB-70A required two conscious,deliberate actions on the part of the pilot to touch off a finely integratedsequenceofevents,mostofthempoweredbyexplosivecharges.

Slowly,inexorablytheXB-70Astartstoslideoutofthesky.

Above:Withtheformationnowspreadwideopen,theXB-70Aentersthelastfewsecondsofstableflight...

Right:Beforedroppingnosedown...

Bottom:andthenfallsoverontoit’sback...(USAF)

MorepicturestakenfromtheLear.

TheXB-70Aspiralsdown,fuelstreamingfromthedamagedfueltanks.

Thecloudcoverbelowformsareferencepointtoorientatetheview,especiallywhennopartoftheLearisintheframe.Thelowerpictureisoftenreproduced‘upsidedown’asiftoshowtheaircraft

wasrotatingalotworsethanitwas.

Neverthelessthestreamingfuelshowsthattheaircraftwasnolongerflying.(USAF)

MajorCarlSCross.

Thefirstactionwastopullupeitherorbothhinged,yellowhand-gripsbuilt into the front edgesof the armrests.The secondactionwas squeezeeither left or right or both triggers set into the yellow handles. Thissimultaneouslyslammedthepilot’sseatbackaboutoneandahalffeetdeepinto the upright box of the capsule and jerked his shoulder harness sorigidlytightthathecanscarcelymove.Italsoshovedtheaircraft’scontrolcolumnforwardtoprovideroomforthecapsule’sclamshelldoorstosnapshutfromtopandbottom.Thedoorsrespondtoaninvoluntaryhumanactwhen,beingwhippedbackintothecapsule, thepilot’sheelswhackintoapairof‘kickers’ashislegsarebeingdoubledupintoanear-fetalposition.

Whenallthishasbeendone,thepilotissealeduptightinanindividualmetalboxwhichcarriesitsownlife-supportsystem.

Thepullingofthetriggerssetoffthefinalsequence:firsttheoverheadhatchblewoff, rapidly followedby the firingof al rocketwhich shot thecapsule,pilotandall,300feetabovetheaircraft.

White’s first action slammed him back into the capsule recess and,according toplan, jerkedhisshoulderharness tighter thananycorset.Hisheelsstruckthedoor-triggeringdeviceandsetoffthatcharge.Buthewasimmediatelyconsciousofexcruciatingpain.FightingtheforcesoftheXB-70’sspin,hisrightelbowhadbeendoubledoutwardashepulledtheyellowhandle,andnowitwastrappedoutsidethecapsuleatthehingepointoftheclamshelldoors.Asaresultthedoorscouldnotcloseshut,sixinchesofhisowndoubledelbowwasoutsidethecapsuleand,withtheshoulderharnessstrainingbackward, his right hand jammedagainst theyellowhandle andtheelbowlockedoutside,hecouldnotgetfree.

‘Thecapsulenotonlyhadmetrapped,but ithurt likehell. Iwassurethearmwasbroken—attheminimum.’Whiterecalledlater.

Usinghislefthand,Whitepriedpainfullyathisrightfingers,tryingtowork them loose from the yellowhandle.Theywould not come free.Hecouldhavepulledthelefttriggerandfiredhiscapsuleoutoftheplane.Buttheclearancebetweentheejectingcapsuleandedgeofthehatchframewasonly four inches.Hadhepulled the trigger,partofhiselbowwouldhavebeen sliced off as though by a guillotine. Spinning, in agony, and beinghauledintwodirections,heknewwhattheprospectwas.

JosephAlbert‘Joe’Walker,(1921-1966)

‘It didn’t help any that, with that crazy tumbling and the spin, I wascompletelydisoriented.AndIcouldseeCarlCross.Hisheadwasbobbingaroundas thoughhewasworking realhardat somethinghimself. I don’tknowwhy,butIknewhehadn’tbeguntoencapsulatebecausehewasstillforwardinthething:hisseatdidn’tmoveback.ThatwaswhyIcouldstillseehimoutofthecornerofmyeye.Iwantedtotalktohimandtriedtoyell,butIguesswiththepainandconfusionIwasonlygrunting.’

The doomedValkyriewas falling fast andWhite, having been pulledawayfromtheinstruments,hadnowayofknowinghowsoontheXB-70Awouldhit.Hewrestledfranticallywithhisarm.

‘Istoppedonce.Itsoundsinsane,butIdebatedwhethertoejectandcutmyarmofforstayandgoinwiththeairplane.AndtherewasCarltothinkabout,eventhoughtherewasnopossiblewayIcouldphysicallyhelphim.”

ThenWhite’s lefthandworkedone right finger free, thenanother,thenallofthemandhepulledthenowunlockedhandawayfromtheyellowhandle. In agony, he finally dragged the wounded arm and elbow insidewithhim.Whitesaidthatitseemedasifminutespassedwhilehewrestledwiththearm,butactually justabout86secondselapsedbetweenthetimetheXB-70begantopplingoutofcontrolandhischuteblossomed.

“OncethatarmwasinIdidn’twasteanytime,Ididn’tknowwherewewereorhowclose togoing in. I pulled the trigger, the rocket firedand Iwentoutwiththecapsuledoorsstillopen.TheshotgavemyheadahellofajerkontopofthesnapintheneckI’dgotwhentheseatwentback.”

TheXB-70’sescapecapsuleseeninthecorrectconfigurationduringtesting.Theclamshelldoorsatthefrontareclosed.Thestabilizing‘arms’aredeployedtotherear,eachwiththeirowndrogue

chutesandthecushioning‘attenuatorbag’hasbeendeployed.(USAF)

Thecapsuledoorswerestillopenwhenheejected.Sincehewasnowwellbelow15,000feet,hischuteopenedalmostimmediately.Anewperilwas immediate - thespinningXB-70Aswungpastwhatseemed likeonlyinchesfromhiscapsule.

‘That long nose went by and I thought God, the next time that bigbastardcomesaroundit’sgoingtogetme.AtthatpointtheairplaneandImusthavebeenfallingatthesamespeed.Itscaredme.”

ThecapsuledoorswerestillwideopenandWhitewantedthemclosed.Although thechargewhichshouldhaveclosed themwasgone theycouldbeclosedmanuallybypullingahandleontheupperdoor.

Whitewanted themclosedfor tworeasons.Hefeltexposedwithonlythe nylon straps of his harness between him and the void. The secondreasonwasmoreimperative:histrappedarmhadinterruptedonemorevitaleventintheescapesequence.AtthataltitudeanXB-70Acapsule,weighingwithpilotapproximately800pounds,fallsfastevenwithitsparachuteopen-32feetpersecondcomparedtotheapproximate22fpsofamanwithanordinaryparachute.Toabsorbtheshockoflanding,apneumaticcushion-calledthe‘attenuatorbag’-shouldhaveinflatedautomaticallyasthemainchute deployed.But it had not done so because the bag could not inflatewith the lowerdooropenandswungdownagainst it.Alwanted thedoorclosedsohecouldinflatethebagwithamanualbackupsystem.

Smokebillowsupintotheskyafter62-0207hittheground.Theaircrafthadimpactednear‘ThreeSisters’afewmilesfromBarstow,California.(USAF)

‘Ididn’twanttohitwithoutthatbladderblownup.Theengineershadcalculatedthattolandwithoutthebagmightcostamanabrokenback.Butitdidn’twork.EvenafterIgotthedoorsclosedIcouldn’tfindit.1wasstilldisorientedandconcernedaboutalotofthings:Carl,whetherhewasout:thejunkfallingaroundme:andaterriblecoldness.Shock,Iguess-thatontopofthesweatfromworkingtofreemyarm.

Then I heard the XB-70A hit. It made a terrible explosion and anenormousplumeofsmokecameup.

Cottonwatched the descending parachute and thought for a time that

Whitewould fall into theXB-70’spyre.But thenhe saw that an easterlywindwouldcarrythecapsuleclear.

Atfiveminutesand22secondsaftertheaccidentandfourminutesand11secondsbehindhisdeadaircraft.White’scapsulewasabouttohit.

“I saw a big Joshua tree coming up and thought God, I’m going infast,”

Withoutitsshockbladder,thecapsuleslammeddownonarockyslopeclose by the XB-70s severed left wing and about a mile from the mainwreckage.Theengineerslatercalculatedthatthecapsule’simpactcreateda45G-force.SomehowWhitemanagedtoavoidthepredictedbrokenback-itwasprobablyahelpthattheseatfasteningsgaveawayandgavehisbodysomecushioningeffect.Nevertheless,hehitsohardthathisrightbootheelstampedadeepindentonthecapsulefloorandonekneeleftitsmarkinthelowerdoor.AlWhitewasbadlyhurt.

AlWhite’sescapecapsulewhereitcametorestonthedesertfloor.(USAF)

Atsixminutes25 secondsafter thecollision.CottonandHoag -whohad made a number of low passes over the wreck site in their T-38 -reportedno activity around the capsulewhichhad tippedoveron its sideandfaceddownhill.

InsideAlWhitewas struggling to break free.Onebig canof capsuleequipment had broken loosewas jammed against his helmeted head - hewasalsopinneddownonhisinjuredrightarm,soonceagainhehadonlyhislefthandtoworkwith.

‘Iwasreallymoaning.Icouldhearmyself.AndIwasfreezingcoldandstiffeningupfast,butIwantedoutofthere.Iwantedmyfeetontheground.Itriedtopryopenthetopdooranddidcrackit,butitsnappeddownagain.Thesecondtime,Igotmyhelmetoffandintothecrackandworkeditbacktoward thehinge likeawedge.When Ihad thedooropenabouteighteeninches, I stuck my head and shoulders out. I saw the T-38 go by andwaved.”

Left:Partofawingtipof62-0207hittheground.Themainwreckageoncethefireshadgoneout.(USAF)

TheremainsofJoeWalker’sF-104.(USAF)

Cottonsawthewave.At13minutesandonesecondafterthecollision-seven minutes and 56 seconds after the capsule hit - Cotton reported:“Thereisactivityatthecapsule...Thecapsuleisonitsside...Thepositionhasbeenchangedandwesawwaving.’

White was able to force his body all the way out but then, sweatingfromtheworkhehaddoneandbonecoldwithshock,hecrawledbackintogethisflightjacket.Itwasn’tenough,andsohestaggereduptheslopeandwrappedhimselfintheparachute.Thatmayhavebeenamistake,forwhenthe firstof the rescuehelicoptersarrived fromEdwardsabout35minutesafterhelanded,hewasintroubleagain.

‘Itwastoorockyandsteepforthechoppertoland,butthedownwashofitsbladesinflatedmychuteandIwasalmostairborneagain’.

The helicopter dropped off a rescue team about 50 yards fromwhereWhitelay.AstheygottoWhitewithastretcherpanicsetin.Hemayhaverecently fallen 25,000 feet, but nowWhite begged the stretcher-bearers,‘Don’tdropme,don’tdropme!’

The wreck site was a few miles north of Barstow, California. MajorCross’s bodywas found in theXB-70Awith his seat still forward in theejection capsule. He may never have been able to begin the escapesequence, perhaps because of the same violent forces which had nearlykilledAlWhite.

TenmilesfromthewreckageoftheXB-70,neitherthecharredruinsofJoe Walker’s Starfighter nor his decapitated body could reveal anythingaboutwhyhehaddied.

PresidentLyndonBJohnsonissuedastatementat17:00,readbyBillDMoyers,SpecialAssistanttothePresident,athisnewsconferencefromtheWhiteHouse. ‘JoeWalkerandMajorCrossgave their lives inadvancingscienceandtechnology.Theirdeathsremindushowdependentweareonmenofexceptionalabilityinthedevelopmentofnewvehiclesinflight.Theydied while training for demanding assignments in a new field of majornational interest-research on supersonic transport flight. They addedimmeasurablytotheprogressthisnationismakinginthateffort.

Iextendmydeepestsympathiestotheirfamilies’.

LetsallplaytheblamegameWithanymajortestprogrammethereisalwaysahigherthannormalriskofincidentsandaccidents-that’swhyitscalledflighttest.

By theweek’s end, as theAirForce conveneda62-memberboardofinquiry,fewthoughtthatWalkercouldhavecarelesslyrammedthebomber;therewas speculation that turbulenceor theB-70’s backwashmight havecausedthecollision.Butthecircumstancessurroundingtheaccidentraisedotherquestions.ThoughitwasstandardprocedureformanufacturersofAirForceequipment to takepicturesof theircraft in flight,bothforpublicityand research purposes, even Pentagon officials conceded that lastweek’sspectacularline-upwashardlystandard.

InWashington,ChairmanGeorgeMahonof theHouseAppropriationsCommittee,declared:“Thelossofthesemen,andanaircraftinwhichmorethan $500 million has been invested, while accommodating the publicrelationsdepartmentofaprivatecompany,isindefensible.”

In fact, the B-70 cost closer to $750 million, but what was notmeasurable indollarswere the livesof twopilotsand the futurehoursofsupersonicresearchthatwerelostintheMojavedesert.

The furore that followed the crashwas hard to believe. Fingerswerepointed in every direction and it became obvious that scapegoat creationhad begun. General Electric bore the brunt of a great deal of unfair andundeservedcriticism.Thephotosessionhadbeenrequestedunderthesamerules, formal or informal, that hadbeen followeddozens of timesbefore,andtheAirForceapprovedtheroutinerequest.Aftertheaccident,industryand Air Force heads were on the chopping block. Congress and theAdministration wanted to see someone - anyone - disciplined, and therewereplentyof‘expendable’peopletochoosefrom.Careerswereaboutto

bedestroyedandliveswereabouttoberuined.The accident took place on 8 June 1966 - the final report of the

AccidentBoard, signedby itspresident, aUSAFcolonel,was issued justforty-ninedayslateron27July1966.Itallseemedremarkablyquick-soquick in fact that somehavedoubted that itwas as thoroughas it shouldhavebeen.

GeorgeHermanMahon(22September1900–19November1985).HecalledthelossofAV/2‘...indefensible’.

Atfirstlookthereportappearstobethorough,butacloserstudyandacertain amount of thought indicates that it may well have been hurried.Indeed, the report was published before all the wreckage had beenrecoveredandexamined!

The accident involved the loss of two lives and the loss of a $500-million airframe, that was highly advanced in both materials andconstructionandwasequippedbymanynewandunprovensystems.Italsoinvolvedthedestructionofhalfofaresearch‘fleet’thathadaprogrammecostofnearly$1.5billion.Onecanunderstandwhysomanysuspectedthatno matter how obvious the circumstances of the mid-air collision, theinvestigationappearedtobeshorttothepointofacover-up.Waspressureputonthewriterstoputthepastbehindthemassoonaspossible?

It appears there was an effort within the Air Force to complete theinvestigationandthen try toforget it.Followingpublicationof thereport,SecretaryoftheAirForceHaroldBrownwroteasummaryonthereporttoSecretaryofDefenseRobertMcNamaraon12August1966,makingitveryclear that he was not going to accept responsibility for the crash. Hementioned‘instructions’and‘procedures’thatwerenotfollowedandmade

referencetoalackofcoordinationwiththeassistantSecretaryofDefenseforpublicaffairs.TheAirForceleadershipwasnotgoingtoacknowledgethe photographic mission as standard procedure, even though the memonever spelled out which regulations were violated. It contained nothingabout why such photo missions had been taking place openly for yearswithoutcommentfromAirForceleadership.

Brownstatedthatunderestablishedprocedures,requestsforAirForceassistanceintheproductionofcommercialfilmsrequiredapprovalatahighlevel. He indicated that this procedures list included not only theatricalmotion pictures, but also industrial motion pictures of advertising value.Thedirectorof informationfor theAirForcewassupposedtobethesoleauthority.

The director of information was supposed to coordinate with theassistant Secretary of Defense (Public Affairs), who had the primaryresponsibility for relationswith industry. InviewofSecretaryofDefenseMcNamara’sdesiretomicro-manageallofthepressandPRreleasesforalltheservicesincludingNASA,thispracticewouldnotseemunusual.

Other directives prohibited flights of USAF aircraft not in the directinterest of government business. Air Force participation in contractor-sponsoredspecialeventswasrestrictedandwasnot tobeused tosupportcommercial advertising, publicity, or promotional activities.Office of theSecretary of Defense approval was required on all aerial reviews nototherwiseauthorized.

BrownmadeitclearthattheXB-70Aflightinquestionneverhadsuchapproval for theGeneralElectricpartof the flight.Brownconcluded thattheAirForceofficerwhoassistedGeneralElectricwiththisexerciseusedpoorjudgment,andthatthisofficer’ssuperiorwasalsotoblamebecausehedidn’t exercisegood judgment inhisduties.TwootherAirForceofficerswere cited: ‘an Air Force information officer and an official at the nexthigher level of the XB-70A program, both of whom were aware of theformationflightbutfailedtodoanythingaboutit.’

Browndrewhisprologuetoaclose,statingthatfurthermeasurestakentoensurethatthelessonsofthisaccidentwerelearned.

In his report Brown reviewed all the contracts held with NorthAmerican Aviation and General Electric. There were, of course, noprovisions made for photography for nongovernmental purposes - theywere not authorized or required. The photographic aspect to thismission

wastherefore‘...outsidethetermsofthesecontractsandcouldnotproperlyhavebeenundertakenunlessapproved inaccordancewith theprocedureson pictorial and industrial relations activities noted at the outset’. Thisstatement says that thiswas an illegal flight sanctionedby theAirForce,whichsaidthatitsofficersactedincorrectly.

Brown’s summary of theXB-70Adisaster showed just how hurriedlythisreportwasputtogether,presumablysothatitcouldbesweptundertherug. Nothing could have pleased RobertMcNamaramore. Not only wasthereresistancetofindingouttherealreasonsfortheaccident,butBrownalsoseemedinsistentthatGeneralElectricwastobeblamed.Theapparentattitude was that none of this would have happened if General Electrichadn’taskedforthephotoflight.

Colonel Cotton would be assigned the blame for not refusing therequestandoverridingNorthAmericanAviation’sreluctancetocooperate.Colonel Cate would take the blame for his limited view of his approvalauthority-which,incidentallyneverseemstohavebeenchallengedbeforein other photo-opportunity issues. And, of course, McCollum would beblamedfornotstoppingtheflightaltogether.Nooneeverquestionedwhythispracticehadoccurredsomanytimesbeforewithoutobjections.

AccordingtoBrown,all thosepeopleandcompanieswereworkingincomplete‘...ignoranceoftheprescribedprocedures,ratherthanwithintenttoviolatethem’.Hequestionedthejudgmentofthepeoplewhomadethiswhole episode possible: the Air Force, the civilian contractors and, ofcourse,theGeneralElectricCompany.Convenientlynotmentionedwastheoffice of the Assistant Secretary of Defense (Public Affairs), apparentlybecausetheyhadnotbeeninformedoftheflight.

BrownstronglyimpliedthatthisaccidentwouldneverhavehappenedatsomethingaslegitimateasanArmedForcesDayevent.SuchaflightwouldhaverequiredtheapprovaloftheAirForcedirectorofinformation,andtheassistantSecretaryofDefense(PublicAffairs).Hecitedtheearlierinstancewhere merely for the XB-70A to appear an air show at Carswell AFB,Texas, the requesthad reached thehighest levelof theAirForcechiefofstaff and the Secretary of the Air Force, and then the appearance waslimitedtoastaticdisplay.WhyitwouldtaketheapprovaloftheAirForcechief of staff to approve a static display, but a formation flight could beapprovedbyasecretaryofanaircraftinthelineofduty,waypasttheinitialflightteststage.Accidentshappen.It’sanunfortunatefactoflife.Couldthe

loss of the second XB-70A have been prevented? We may never know.Bureaucracyplayeda largepart in the inquest that followed the accident.Headsrolled,blamewashandedout,andchangesweremade;buttheywerelargelyfutilepoliticalsolutionsthatcametoolateandsettlednothing.

ManyquestionedthecompetencyofJoeWalker.Itwassaidbyawell-knowntestpilotthatWalkerhadnobusinessbeinginthatformation.Washewasoutofpractice?Walkerwasapilotwithalmost5,000hoursofflighttime,andover750hours in theF-104.Noonereallyknowsexactlywhathappenedupthere.SomeassumeWalkerwasn’tpreparedtoflyformation,others think he took his eyes off the Valkyrie to watch a B-58 that wascomingdownthecorridor,ormaybehejustgotcaughtinthevortexoftheXB-70Aafterallowinghisaircrafttocreepdisastrouslyclosetoit.

Afterallthebloodletting,thepoliticalpunishmentexercisewasunabletobringtwodeadpilotsbacktolifeortoreplacea$500-millionaircraft.

SOHOWDIDITFLY?

TheXB-70wasanincrediblycomplexpieceofequipment.Preparationforeachflighttookthemany‘departments’manyman-hourstocomplete.Theaircraft had twenty-one servicing points, all of which needed attention.ApartfromtheJP-6fuel-ofwhichnoalternativewasallowed-theaircraftneeded liquid nitrogen, demineralised water in the form of ice shapedspecificallytofitthecontainers,speciallubricants...thelistwashuge.

The aircraft’s requirements and size may have been large, but thecockpit itselfwas tiny. Itwasdominatedby the twoescapecapsules, andthenalmostalloftheresttheavailablevolumewascrammedfullofdials,switches and levers. Both machines had a somewhat strange mixture ofrotationalandlineardialsthattodayconfusetheeyeandthemind.

Totakeoff-fromthecockpitBoth thepilot and the co-pilot had specificduties according to theFlightManual.However,muchofthedetailedpre-flightinspectionwaslefttothemaintenancepersonnel:‘Duetothesizeandcomplexityofthisairplane,itis assumed that maintenance personnel have completed the preflightinspections.Theexteriorinspectionperformedbytheflightcrewisonlyaninspectionofthereadilyaccessibleandflightsafetyitemsandisbasedontheflightcrewacceptingtheairplaneforflightwithemphasisontheitemsaffecting safety of flight. Check the airplane as outlined in Section 2.1.Informationonnon-accessible items is listed in the‘Pre-Flight InspectionRecord’.Ground crewwill be at the airplane to discuss the status of theairplaneanditssystem’.

Section2.1Pre-flightExteriorInspection.1-Forwardfuselagearea.2-Rightcanardarea.3-Rightinletarea.4-Nosewheelarea.5-Weaponsbayarea.

6-Rightmainlandinggeararea.7-Rightwingtiparea.8-Rearfuselagearea.9-Leftwingtiparea.

10-Leftmainlandinggeararea.11-Leftinletarea.12-Leftcanardarea.

Thetwelveexternalareasof inspectioncontainedthirtysevenspecificitemsthatexcludedcheckingthatallgroundequipmentwasconnectedandworking.Once on board therewas a further twenty three point list to be

completedbeforethecockpitcouldbe‘setup’forflight.Once in theirseats theflightcrewfacedpagesandpagesofpre-flight

‘instructions’. As each of the two aircraft varied slightly, there weresections specifically relating towhichevermachinewas being readied forflight.Enginestartoccurredatthebottomoftheseventhpage.

ThenormalstartingsequenceisenginesNo.4,6,5,3,1,2.Whenthefirst throttle is moved from OFF to IDLE the cooling loop fuel pumpcautionlightgoesout.However,aseachengineisstartedonecoolingloopfuelpumpcautionlightcomesonandstaysonuntilenginerpmisbetween35and40%.

Afterthefirstengineisstarted,andduringthestartofeachsuccessiveengine,observethatengineandADSoilpressurelightscomeonwheneachthrottleisadvancedtoIDLEandgoesoutafterstart.Thisprovidesacheckonthepressureswitchesandelectricalcircuits.

Therewerethenanothertwentypagesofactionsbroughtaboutbycallandresponsesbetweenthetwocrewonboardbeforetheaircraftwasreadytotaxi.

Itwastheninstructionstothegroundcrew:‘Landinggearsafetypins,wheelchocksandclearairplanetotaxi.Thethreelandinggearsafetypinswillbedisplayedtothepilotwherehecanseeandcountthem.

Nose wheel steering selector switch - TAXI. Nose wheel steeringselectorswitch-ENGAGE,checknosewheelsteering-ONindicatorlightON,thenmoveswitchtoFAILSAFE.

Hydraulic pressures, fluid levels and pump status indicatorsCHECK.Groundintercom-havegroundcrewdisconnect.AGPSmagneticandgreatcircle headings -CHECK.AGPSmode switch -MAG.Apply brakes andreleasepedals.CheckthatBrakeHoldlightgoesout.

Before taxiingbe sure that there isproper clearance for theairplane.(seeFig2.4 forminimum turning radius).Note over thenose visionwiththe nose ramp retracted to runway level is about 90 feet in front of theairplane.

Theidlethrustofsixenginesisadequatefortaxiing.Directionalcontrolshouldbemaintainedbynosewheelsteeringratherthandifferentialthrustorbraking.

Duringtaxiingfivemorepointsonthelonglisthadtobecovered.Thebrakeswere checked, alongwith the hydraulic pressure, aswas the nosewheelsteering.Bothcrew’sturnneedle,ADIandHSIwerechecked,with

theattitudedirectorandhorizontalsituationindicatorswereworkinginthecorrectmanner.ThewheelbrakecontrolswitchwassettoAUTOMATIC.Bothbraking systemswere checkedbyusing thewheel brake test switchheldtoSYS1thenSYS2andapplyingthebrakeswiththeswitchineachposition.

AirVehicleOneundertowatEdwardsAFB.InthebackgroundcanbeseeAirVehicleTwo.(USAF)

Figure2.4fromtheFlightManual-theminimumturningradiusoftheXB-70A,basedonthenose

wheelsturned58degreesfromcentre,withthenosewheelsteeringswitchintheTAXIposition.

1-Thepitotboomtip=142feet.2-Wingtip=97feet.3-Nosegear=54feet.

4-Leftmaingear=40Feet.5-Rightmaingear=27feet.

On arrival at the take-off area the aircraftwas brought to a completestopforanotherseriesofchecks/actions.

1.

ACvoltages-Check.Checkeachphase(A,BandC)ofACvoltageforeachacbus(LHPRI,RHPRI,andessential).Voltageshouldbe115volts+/-3volts.WhenthecheckisoverleavethebusselectorswitchtoESSENTIAL.

2.Co-pilot-AirInductionControlSystem-Check.Bypassareashouldbe0000squareinchesandThroatMachscheduleindicatorshouldbeat1.67.

3.

Secondaryexhaustnozzlestandbypressureknob-checksetatfieldelevation.Caution-ifthenozzlestandbyknobisimproperlyset,theautomatictransferoftheambientpressuresignaltothenozzlestandbycircuitintheeventofcentralairdatacomputerfailuremaycauselossofthrust.

4.Co-pilot-LiquidNitrogenquantityindicator-checkquantity.5.Co-pilot-IFFMasterSwitch-NORMAL.

ThediagramfromtheFlightManualandcorrespondingpictureofthepilot’sinstrumentpanel.(Author)

6.Tiresandbrakes-havegroundcrewcheck.Groundcrewwillcheckbraketemperaturesandvisuallychecktiresforcuts,abrasionsandproperinflation.

7. FlightControls-checkforfreedomofmovement.8. CanardFlaps-Havegroundcrewcheckposition.

9. Take-offTrimButton-Pressandholduntillightcomeson,thenrelease.10.Hydraulicspressures,fluidlevelsandpumpstatusindicators-Check.11. Takeoffdata-review.

12.

EngineOverspeedArmingLever-OUT.Note-Whentake-offconditions(ambientairtemperatureabove50°Frequireengineoverspeed(104%RPM)operationtoprovideextrathrust,theoverspeedarminglevershouldbepulledbackintoitsarmed(ARM)positionbeforethethrottlesareadvancedfromIDLE.Theoverspeedarmedcautionlightcomesonpusheithermastercautionlighttoextinguishbothmastercautionlightsandtoresetmastercautionlightcircuit.Anti-collisionlightswitchON.Caution-Operationoftheanti-collisionlightsonthegroundshouldbelimitedasmuchaspossible,asthebulbsmaybedamagedby

13. overheating.Note-Operationoftheanti-collisionlightsonthegroundshallbeheldtoaminiumbecausegroundemergencyvehicleshavesimilarlights.Theoperationoftheanti-collisionlightscouldconfuseandhampergroundrescueoperations.

ThediagramfromtheFlightManualandcorrespondingpictureofcentreinstrumentpanel.Notetherearesomedifferencesbetweentheflightmanual-whichisdated25June1965-andtheinterior

photograph,whichwastakenafterthelastflightof62-0001.(Author)

14.

Ammoniaandwaterquantitygages-checkthatsufficientamountsofammoniaandwaterareavailableforcompletionofthemission.Caution-Ifammoniaisbelow275pounds,orwaterisbelow4000pounds,aborttheflightuntilammoniaorwatertankisrefilled.

15.Co-pilot-Onaircraft62-001-BypassareaandThroatMach-checkbothbypassareasclosedandboththroatindicatorsat1.6716.Onaircraft62-0207.Co-pilot-AICSmodeswitchescheckbothSTBY.

17.

Co-pilot-Fuelquantity-Tanks8Land8R-checkquantityat13,500poundsorlesson62-001.Tank5-checkquantityat26,000poundsorlesson62-0207.Iffuelquantityinspecifiedtankisabovetherecommendedlevel,movecorrespondingfuelpumpswitchtoOFFuntilfuellevelisreduced.Co-pilot-FueltankpumpswitchesAUTO.MoveNo.6fuelpump

18. switchtoAUTOandcheckincreaseintankNo.3quantity,thenmoveallremainingfuelswitchestoAUTO.

19.Co-pilot-TankNo.3checkathighlevel.MakesurefuelistransferringproperlytoNo.3sumptank.Thesumptanktapewillindicatefullifpropertransferistakingplace.

20.GroundIntercom-Havegroundcrewdisconnect.21. Bothpilotandco-pilottoremoveCapsuleflightstatussafetypins.22.Co-pilot.PitotheaterSwitchON.OncepermissionwasgrantedfromAirTrafficControl,theValkyriecouldentertheactiverunway,lineupandthenholdwhile:

ThediagramfromtheFlightManualandcorrespondingpictureofco-pilot’sinstrumentpanel.(Author)

1.Nosewheelsteeringselectorswitch-TAKE-OFFLDG.Note-nosewheelsteeringremainsengagedwhenswitchismovedfromTAXItoTAKE-OFFLDG.

2.Nosewheelsteeringengageswitch-FAILSAFE

3.

Throttles-advanceto81%.Caution-Topreventpossibleenginevibration,thefollowing‘detented’throttletechniqueisrecommended.WhenmakingthrottleburstsfromIDLEtoMIL(orgreater)accelerateto80%or90%RPMandholdthisspeedlongenoughtoobservestablerpm.Ifvibrationiswithinlimitsaccelerateenginetothrottlepositionasrequired.Duringallflightconditionswhereflightidleisgreaterthan80%rpm,throttlemovementsareunrestricted.

4.Co-pilot-RefrigerationswitchON.ElectronicAirEquipmentTemperatureGauge-Checkdecreasing.Water-Ammoniacautionlightout.

5.

Throttles(ifrequired)-MIL.IfMilitaryThrustcheckhasnotbeenmadebeforeline-up,advanceallthrottlestoMILandallowenginestostabilizefor30seconds.Makesureallconditionsarecorrectandwithinlimitsandcheckexhaustnozzlepositionindicatorsareatabout40%.

6. Throttles85%rpmThrottles70degrees.Advancethrottles3and4rapidlytoMINA/Band,

7.

afterafterburnerlight-off,continuetoadvancethrottlesto70degrees.Repeatprocedurefromengines2and3,andthenforengines1and6.Caution-toprecludestallingtheotherenginesifoneenginestalls,engageonlyoneafterburneratatimeperinlet.Becausetheoperationintheminimumafterburnerrangemaycauseunstablecombustion,whichcouldresultincompressorstallsand/orengineflameout,avoidafterburneroperationwiththethrottlebetween61-and70degreesettings.

ThediagramfromtheFlightManualandcorrespondingpictureoftheCentreConsole.(Author)

8. EnginesInstruments-check.

9.

Wheelbrakes-release.Usenosewheelsteeringfordirectionalcontrolatspeedsuptonosewheelliftoff(approximately10knotsISAbelowtake-offspeed).Itisnotrecommendedthatdirectionalcontrolbemaintainedbyuseofwheelbrakesbecausebrakingactiongreatlyincreasestake-offroll.

10.

ThrottlesMAXA/BorOVSP.AdvanceallthrottlessimultaneouslytoMAXA/Bor,ifabove50°Fandoverspeedisrequired,throughtheMAXA/BsettingtoOVSP.Monitorengineinstruments.Caution-Selectedoverspeedoperationshouldnotbeusedfortake-offbelow50°F.Exceedingoverspeedlimitationsmaydamageengineturbinesection.Note-togointooverspeedafterthrottleshavebeenmovedtoMAXA/B,thethrottlesmustberetardedslightlytoreleasetheoverspeedsolenoids.TheoverspeedarmingleverisplacedinARMEDandthen

thethrottlesmovedtotheoverspeedposition.Thepointersoftheexhaustnozzlepositionindicatorsshouldbewithinthegreenarcformaximumafterburnerorinyellowarcforoverspeedoperation.

11.

Accelerationspeed-check.Theaccelerationshouldbecheckedandadecisiontoeithercontinuetake-offortoabort.Atabout20knotsISAbelowtake-offspeedforthegrossweight,begintorotatetheairplaneatsucharatethatitwillassumethepitchanglerequiredforlift-offattherecommendedtake-offspeed.Maintaintakeoffattitudeafterbreakinggrounduntilsufficientairspeedandaltitudeareattainedtopreventsettlingbackontherunway.Warning-Theairplaneshouldnotberotatedtotake-offattitudebeforethenosewheelliftoffspeedhasbeenattained.Ahighangleofattackpriortotake-offspeedwillreduceaccelerationandincreasetake-offdistance.

FromtheFlightManualcomesthistypicalinitialtake-offandclimbawayprocedure.

Standardisingflightreporting

InApril1972NorthAmericanRockwellproducedthe‘B-70AircraftStudyFinalReport’.Within itwere a number of pilot’s flight reports - some insummary, others specific. Thiswas a complete section that described theaircraft,itshandlingandoperationisdetail.ItwascompiledbyAlWhite,who made use of the Cooper-Harper rating scale in applying subjectivevaluationtotheaircraft.Thiswasandisasetofcriteriausedbytestpilotsandflighttestengineerstoevaluatethehandlingqualitiesofaircraftduringflight test. The scale ranges from 1 to 10, with 1 indicating the besthandling characteristics and 10 theworst. The criteria are evaluative andthusthescaleisconsideredsubjective.

TheCooper-Harper scale cameabout afterWorldWarTwo,when thevarious U.S. military branches sent different models of their operationalaircraft to the Ames Aeronautical Laboratory located at Moffett FederalAirfield inMountainView,California for evaluation of the planes’ flightperformance and handling qualities. The laboratory was operated byNACA, thepredecessorofNASA.Mostof the flightswereconductedbyGeorge Cooper, Bob Innis, and Fred Drinkwater and took place at theremotetestsiteattheCrowsLandingNavalAuxiliaryLandingFieldinthecentralvalleyareaeastofMoffettField.

What may be the most important contribution of the flying qualitiesevaluation programs and experiments conducted on the variable stabilityaircraft at Ames was George Cooper’s standardized system for rating anaircraft’sflyingqualities.Cooperdevelopedhisratingsystemoverseveralyearsasaresultoftheneedtoquantifythepilot’sjudgmentofanaircraft’shandlinginafashionthatcouldbeusedinthestabilityandcontroldesignprocess.Thiscameaboutbecauseofhisperceptionofthevaluethatsuchasystemwouldhave,andbecauseoftheencouragementofhiscolleaguesintheUnitedStatesandEnglandwhowerefamiliarwithhisinitialattempts.

TheCooper-HarperRatingsScaleusedbytestpilotstoevaluateaircraftundertest.

Cooper’sapproachforcedaspecificdefinitionofthepilot’staskandofits performance standards. Furthermore, it accounted for the demands theaircraftplacedonthepilotinaccomplishingagiventasktosomespecifieddegree of precision. TheCooper PilotOpinionRating Scalewas initiallypublished in 1957. After several years of experience gained in itsapplicationtomanyflightandflightsimulatorexperiments,andthroughitsusebythemilitaryservicesandaircraftindustry,thescalewasmodifiedincollaboration with Robert (Bob) Harper of the Cornell AeronauticalLaboratoryandbecametheCooper-HarperHandlingQualitiesRatingScalein1969,ascalewhichremainsthestandardformeasuringflyingqualities.

The flight test summarybothpullednopunchesandat the same timesangthedesignspraise,whentheystated‘TheXB-70hasprovenitselftobeaveryremarkableairplane. Ithasaccomplishedeverymilestone thatwassetdownforit.Noaerodynamicchangeswererequiredinordertoachievetheobjectives;butinspiteofItstremendousperformance,theXB-70isanunfinishedairplane.Itwasoperatedinacompletelynewspeedandaltituderange, but with off-the-shelf navigation equipment and flightinstrumentation that were obsolete for this type of flight operation. Thispilotbelieves thatwithnormaldevelopment, including someaerodynamicrefinement,somesystemchanges,andbetterinstrumentsandnavigationalequipment,thiswouldbeatrulyoutstandingairplane.

AirVehicleOneclimbsawayfromthemainrunwayatEdwardsAFB.(USAF)

Inreadingthispilot’ssummaryreport,considerationshouldbegiventothe fact that the combination of this airplane’s size, weight, and speedranges compares tonootherairplane in existence;and that theprogramwas primarily a research program with ground rules that allowed onlythose changes which were necessary to safely accomplish the testobjectives. In the normal sequence of development to an operationalairplane, many of the opinions and recommendations expressed hereinwould have been made after the initial airworthiness flights. They arepresentednow,fortherecord,andforconsiderationifimprovementscanbemadeforfollow-onprograms.

Ingeneralterms,theXB-70Awasaninterestingairplanetofly.Ithadsomepeculiaritiesduetosize,weight,andconfigurationthatweredifferentfrom most other airplanes. The movable wing tips introduced some newcharacteristics in theairplane thathadnotbeenexperiencedbefore,suchasthewidevariationindirectionalstability,rollpower,anddihedraleffect.

Theairplanehadatremendousperformancecapabilityandwasathrillto fly fromthatstandpoint,but thiscapabilitycombinedwith the fact thatthe airplane was climbed and cruised very near the boundary of theallowable flight envelopequicker and easier thananyother airplane thispilot has flown. The duct pressure limits and the low allowable ‘g’aggravated the recovery. All this adds to the pressure on the pilot byrequiring greater concentration on his part. This was acceptable in aresearchprogramof thisnature,butwouldcertainlynotbeacceptable inanoperationalvehicle.

The potential for a great airplane is here, but some refinements arerequired.More specifically, thepilot’s opinionsand recommendationsareasfollows:

GroundHandlingQualities:Taxiing theairplanewasnotadifficultoperation.Turns fromonenarrowtaxiway to another narrow taxiway was made with acceptable accuracy.However,parkingtheairplaneinapreciselocationwasdifficultbecauseofthe restricted visibility, configuration of the airplane, and lack ofrepeatabilityofthenosewheelsteeringsystem,i.e.,thenosewheelsteeringrate varied with the load on the nose gear so that full rudder pedalapplication did not consistently give the same turning rate. Groundobservers were required for parking, but their inputs were sometimesvalueless due to the steering system’s inability to follow their directions.CooperRatingof3.5.

Originally the braking system was unsatisfactory at very low speeds,but with development, the system became marginally satisfactory. Theairplane could be stopped without brake chatter as long as the pilotanticipatedfarenoughinadvancetobeabletoapplyverylightbrakingtomake thestop. Ifanabruptstopwasrequiredat lowspeeds,heavybrakechatteroccurred.CooperRating4.5.

Checklist-inthecruiseOncethecrewhadclearedtherunwaytherewasnotimetorelax,fortherewasaflurryofactivity.1. Hydraulic Systems - Check pressures, fluid levels and pump statusindicators.

2.LandingGearHandle -UP,below300knots ISA.Checkgearpositionlights.Note.Whenlandinggearisretracted,theruddertravelisreducedautomatically. The +/-12 degrees available when the gear is down isreducedto+/-3degreeswhenthegearisup.Caution -Landinggearanddoors shouldbecompletelyupand lockedbefore gear down limit speed is reached, otherwise excessive air loadsmay damage the doors and gear operating mechanism and preventsubsequentoperation.IfthelandinggearhandlehasbeenmovedtoUPwhiletheweightoftheairplanewasstillonthegear,thehandlemustbe

placedintheDOWNpositionandthenreturnedtoUP(withtheweightoffthegear)beforethegearcanretract.

3.FlapHandle-UPbelow270knotsISA.MoveFlapHandletoFLAPUPbeforereachingtheflapdownlimitairspeed.Therewillbeanose-downtrim change as the flaps are raised. Check flap position indicator andflappressurecautionlightsareout.

4. Electrical and hydraulics - check voltages, hydraulic pressures, fluidlevelsandpumpstatusindicators.

5.Cabinaltitudeandoxygen-checkat8,000feetwhenairplaneisabove8,000feet.

6. Co-pilot - auxiliary cooling switch OFF if electronic equipment airtemperatureisingreenarc.

7.Ammonia,wateroxygenandnitrogenquantities-check.

8.Co-pilot-Fuelsystem-check, fuelsequencing-check, fuel tankpumpswitchescheckemptytanksOFF.

9.Wingtips1/2atMach0.95or400knotsISAwhicheverislower.WingtipfoldmodeswitchcheckNORMAL.NOTE-donotuseALTRtolowerthewing tips. Note a slight nose-up trim change occurswhen the tips arelowered.Foreverychangeofspeedtherewasaseriesofchecklistitemsinthe

Flight Manual that involved both the pilot and co-pilot, much of whichrelated to the engine inlets. Colonel White continues his report on hisexperiencesinhandlingtheXB-70A:In-FlightHandlingQualities:Low Speed: The pitch control in low speed flight regimewas very good.Some lack in airplane response could be detected during abrupt pitchmanoeuvres; however, the response was satisfactory in all of the normalmanoeuvresusedinflyingtheairplane.Thelongperiodoftheshort-periodoscillation was different from most other airplanes, but did not causedifficultyincontrollingtheairplane.Thedampinginpitchwasgoodinthesubsonicflightregime.CooperRatingof2.5.

ThemaindifficultyinflyingtheXB-70wascausedbyacombinationofcharacteristicsinthelateral-directionalsense.Thesecharacteristicswere:First, that the period of the short-period oscillation was very long ascompared tomost other airplanes, secondly, the side force per degree ofsideslipwaslowinthisairplane.Thiscombinationmadeitdifficultforthepilottosenseinadvertentsideslips.Inadditiontothosecharacteristics,theairplanehadamarkedpositivedihedraleffect(particularly#2A/V)andithadexcessiveadverseyawduetoailerons.

AirVehicleTwowithF-104escortseenfrombehind.(USAF)

AirVehicleTwowiththewingtipsinthehalf-downposition.(USAF)

Considering these fourcharacteristics together, ifan inadvertent side-slip occurred without the pilot’s knowledge (who was busy with othersystemoperations),theairplanerolledduetothedihedraleffect.Instinctivereactionof thepilotwas to counteract the rollwithaileron;however, theaileroninputincreasedthesideslipbecauseofthehighadverseyawduetoaileron. This increased sideslip caused more roll away from the aileroninputandaggravatedthesituation.Thesolutionwasthatthepilothadtoflythesidesliporyawindicatorreligiouslythroughouttheflightregime.Thisgeneral characteristic of theXB-70wasmost predominantwith thewingtipsup.CooperRatingof4.5.

Placing thewingtips in theone-halfpositionreduced the tendency forthe situation explained in the previous paragraph, because lowering thewing-tipsreducedtherollpowerbyapproximately50%,thereforereducingyaw due to aileron. In addition, the tips down configuration reduced thepositivedihedraleffectCooperRatingof4.0.

6January1966andAirVehicleOnefliesinformationwithNB52B‘008’.

TheNB-52BwasB-52Bnumber52-0008convertedtoanX-15launchplatform.Itsubsequentlyflewasthe‘Balls8’insupportofNASAresearchuntil17December2004,makingittheoldest

flyingB-52B.(NASA/USAF)

AirVehicleOne-wingtipsfullydown.(USAF)

Visibilitywiththewindshieldintheuppositionwasunsatisfactory.Thepilotcannotseethehorizonaheadandmustmaketheflightalmostentirelywith reference to thepitchattitude indicating system.Thepoorquality ofthe heading information, precise heading, climb schedule made altitudeflyingextremelydifficult. Inaddition, imagesof light-coloredgroundsuchas snow and sandy desert areas reflected badly in thewindshield duringturns,attimescausingvertigo.CooperRatingof5.0.

Unstarts:Theinadvertentinletunstartsencounteredintheflighttestprogram,variedinintensityfrommildtosevere.Theywerebreath-takingtosaytheleast.Inthecaseofasevereunstart,itjarredtheairplaneratherviolentlyandwasfollowed by heavy buffeting, intense aerodynamic noise, and minor trimchanges.AtMach3, theprimary trimchangewas inroll,butusuallydidnot persist since the other inlet would normally unstart within a fewseconds. If the inlet system did not effect an immediate restart, the inletwould go into buzz. The buzz cycle was immediately recognizable to thepilot since it was almost purely a lateral oscillation at about the naturalfrequencyofthefuselage.Ifitwasnotcorrected,itbuiltupinintensitytoaverydisturbing,ifnotdestructive,magnitude.Inspiteoftheseverityofthetransientscausedbyinletunstarts,airplanecontrolwasconsideredgood.

Returntoearth

Descent from altitude followed even more check-lists, before setting theaircraftupforthefinalphaseofthedescentandapproachtotheairfield.1. BrakeControlSwitch-AUTOMATIC.2 NosewheelsteeringSelectorSwitch-TAKE-OFFLDG3. EngineRPMlockupswitch-checkRELEASE.

4.Co-pilot-FuelTanksequenceandquantityindicatorscheckandcheckemptytankpumpswitchesOFF.

5. Landingdata-computeapproachandlandingdistancesbeforeenteringthetrafficpattern.

6. Flightaugmentationcontrolsystemswitch-OFF

7. LandingGearhandle-DOWNandcheckgearpositionlights.Extendgearbelowgear-downlimitspeed.

8. FlapHandle-FLAPDOWNandcheckflappositionindicator.Lowerflapsbelowflap-downlimitspeed.

9. Electricalandhydraulics-checkvoltagesandhydraulicpressures,fluidlevelsandpumpstatusindicators.10. AmmoniaQuantityGauge-check.11. Co-pilot-auxiliarycoolingswitch-checkON

12.Co-pilot-Refrigerationswitch(ifwindshieldanti-iceandrainremovalswitchesareON)-OFF.TheFlightTestSummaryprovidesaninsightintowhattheaircraftwas

liketoflyduringtheapproachandlandingphase:

ThegreatwhitebirdabouttotouchdownatEdwardsAFBafteranotherflight.Thenose-highattitudeisparticularlynoticeable.(USAF)

TheXB-70wasnotadifficult airplane to land.Somecarehad tobeusedduetothedistancebetweenthepilotandthemaingearandduetothecrew station height above themain gear at touchdown. Because of thesedimensions,itwaseasytoundershoottherunway.Aftersomepractice,allpilotswereable tomake satisfactory landingswithoutexternalassistancefromchaseaircraft.

The wing of the XB-70 experienced a strong ground effect in theproximity of the runway which helped considerably in making relativelysmoothlandings.Thesecrettoagoodlanding,likeinmostairplanes,wasagoodstabilizedapproachusingaratherlowrateofdescent(2to3degreesglidescope).

CrosswindlandingsintheXB-70werenotasdifficultaswaspredicted.The relatively shallow bank angle per degree of sideslipmade the wing-downtechniquerathereasytousewiththeXB-70.

Landing in turbulent air required additional pilot concentration,primarily due to previously mentioned relationship between inadvertentsideslip,dihedraleffect,andyawduetoailerons.Thepilotwasrequiredtowatchtheyawindicatorverycloselyinmakinganapproachsoasnottogetintothisinadvertentsideslipconditionclosetotheground.LandingCooperRatingwas3.5.

The Flight Manual provided all the information and procedures thatwereneededtomakeasuccessfullanding.1.Throttles-IDLEattouchdown.Retardallthrottlessimultaneously.Note!Air Induction System Coolant Caution Light will come on when theweight is on the main gear. However, this does not indicate amalfunction.

2.LowerNoseWheels.3NoseWheelSteeringEngageSwitch-ENGAGEthenFAILSAFE.4.Co-pilot-DragChuteHandle-DEPLOYbelow220knotsISA.5.WheelBrakes-asrequired.Avoidexcessivebrakingunlessnecessary,ashighoperatingtemperaturesandexcessivetirewearwillresult.

6.DragChuteHandle-STOWEDJETTISONbelow60/70knotsISA.7.Co-pilot-RefrigerationSwitch-OFFafterlandingroll.8.NoseSteeringSelectorSwitch-TAXI.9.NoseWheelSteeringEngageswitch-ENGAGE.

Aclose-upofthenose‘ramp’intheraisedposition.(USAF)

NormalLandingTechnique.Followingentryintothetrafficpattern,lowerthelandinggearandthe

flapsbelowlandinggearandflapdown-limitspeeds.Flythetrafficpatternatthepreviouslycomputedairspeeds,adjustingthrottlestocontrolrateofdescent.Afterrollingoutoftheturnontofinalapproach,adjustthrottlestomaintain final approach speed for the specific landing gross weight tocontrol rate of descent to touchdown at the desired speed. Retard thethrottles to IDLEafter touchdown.Normal landing touchdownswillbeatabout10degreesnosehigh.

Caution -higher touchdownangles shouldbeavoided,as theengineexhaustnozzleswillstriketherunwaywhentheairplaneisatan11-degreeattitude. Besides the angle-of-attack indicator, the windshield nose rampcanbeusedasareferencetoindicateover-rotation.Thewindshieldnoseramp angle is 11 degrees: therefore, when the ramp becomes horizontalduring touchdown, the airplane is at 11 degrees angle-of-attack. Over-rotationwillbeindicatedwhenthenosestartstoblankoutthehorizon.

IncompilingtheFlightSummary,ColonelWhitecriticallydescribesthecockpit,thecontrolsandthelayout:

Capsule;Thepressuresealsinthecapsuledoorsweretornloosemany

times when the pilots entered the capsules. Entering the capsule,particularlywhenwearing the pressure suit,was very difficult due to thelackofspace.Thesealsshouldbeguardedsothattheyarenotdamagedinthisway.

Theoriginal installationof the capsule handgrip seat pins includedalanyardandatakeupreelwhichwereinstalledbehindthepilotsshoulder.Alargepercentageofthetimethetake-upreeldidnotoperate;andwhenitdidoperate,thepinwasextremelyhardtoreachtoreinstallafterflight.Atemporary fix was made by cutting the lanyard, thereby eliminating thetake-upreel.Thisworkedsatisfactorily,exceptfortheminorinconvenienceofnothavingaplacetostowthepin.

Theemergencyparachuteand riser cutterhandlesand thehinge splithandle were difficult to see when encapsuled. When the pilot raised hisheadtoseethehandleswithhishelmeton,hehadtoraisehishelmetwithhishandinordertoseepast thebowof thehelmet.Thiswasparticularlytruewhenthepilotwaswearingapressuresuitandwasaggravatedunderthedynamicconditionsencounteredafterejection.

Thepressurizationandcapsuleoxygengaugeswereparticularlyhardtosee once in the capsule. The safety belt was almost impossible to adjustafter it has been fastened. The seal deflate button was very difficult toactuateduetoitslocationwhenthepilotwaswearingapressuresuit.

Thehotmikeinterphonecapabilityduringencapsulationwasoperableonly after the capsule doors were closed. It appears wise, after theexperienceof therecentejection, thatthehotmikebeactuatedinanotherwayinadditiontothedoorclosure.Itshouldbeconnectedtothehandgripsso thatwhen encapsulation ismade, the hotmike interphone is availableevenifthedoorsarenotclosed.

Withbrake-chutesstreaming,AV/1rollsoutofitslandingatEdwardsAFB.(USAF)

Themanualimpactattenuatorinflationdevicewasextremelydifficulttogettowhileencapsulated.Itwasrecommendedthatsomethoughtbegiventorelocatingthisdevicebetweenthepilot’skneesforeasieraccess.

The Secondary Nozzle Rheostat: This rheostat is in a poor locationconsidering the number of times it was used during flight. It would bedesirabletomoveit forwardIntheareaneartheoxygenandvisorheaterswitches.

Hydraulic Pump Status Indicators; The hydraulic pump statusindicatorsbecamealmostuselessinviewofthenumberoftimesthepumpstatusindicatorsshowedyellowwiththepumpsoperatingproperly.

Nose wheel Steering System: The nose wheel steering engage buttonideally should be mounted on the control wheel. Originally this was notdone because of lack of space on thewheel. The pilots believed that theaugmentation disengage switch should have the priority location on thewheel. The experience gained in the flight test program indicates that itwould be satisfactory to move the augmentation disengage switch to thesameareaas theaugmentationengagebuttonon theconsoleandput thenosewheelsteeringengageswitchonthecontrolwheel.

TACAN;TheTACANinstrumentationontheXB-70wasonlymarginallysatisfactory. Early in the program the pilots were requested to list theminimumequipmentwithwhichtheycouldaccomplishthemission,andoneTACAN was suggested for navigation. Experience has now shown thatwithout radar tracking and the occasional assistance of theFAA centers,some of the missions would have been extremely difficult to completesatisfactorilyduetothequalityofthisequipmentandinstallation.

62-0001atEdwardswhileinservicewithNASA.Noteallthesegmentedelevonsinthe‘up’position.(USAF)

1-Throttles-militarythrust(MaxA/B)ifrequired.2-LandingGearHandleUP(onlyafteradequateflyingspeedhasbeenattained.

3-FlapHandle-asrequired.4-Climbtotrafficaltitudeormissedapproachaltitude.

5-Throttles-retardtoobtaindesiredthrustreduction.Monitorengineinstruments.

Attitude and Heading Information; The attitude and headinginformationwasmarginallysatisfactory.Thisaddedtothepilot’sdifficultyin navigating the airplane. In view of the above two conditions, it washighly desirable to have a more reliable navigation system. An inertial

platformwashighlyrecommended.AICS Controls: The AICS controls were satisfactory for the

development stages, although the controls in A/V #1 were minimumsatisfactory. It was highly recommended that this system be reviewed forfutureuse.

Flaps;Theflapsystemwasmarginallysatisfactory.Becauseofadesignproblem, the flapsweretoberaisedfor the taxiandloweredjustprior totakeoff in order to ensure that they would retract in flight. Occasionallytheywouldnotextendforlanding,andoccasionallytheywouldnotretractafter landing. The result was that the pilots lost confidence in the flapsystem.Itwasrecommendedthatadesignchangebemadetoeliminatethenecessity of the intricate procedure thatwas required to operate the flapsystem.

MapCase:Themapcasewasalmostinaccessibletothepilots.Inmostcasesthepilothadtogetoutofhisseattogettheequipmentfromthemapcase.Althoughthemapcasewasoflittleusetothepilots, itwastheonlyplace in the cockpit that extra material could be stored. Check lists andpilot’s data cards had to be strapped to the pilot’s legs to be of any use.Some consideration should be given to amore convenient stowage spacefor let-down charts, handbook, and additional maps, particularly if thisairplaneistobeusedforcross-countryworkinthefuture.

Wingtip Selector Switch: If the flaps are lowered for landing prior toraisingthewingtipstotheupposition,itwouldbepossibletolosecontrolof the airplane. It was recommended that a safety device be installed topreventloweringtheflapswhenthetipswerenotintheupposition.

Theairplanehadmoderatebuffetatlowspeedswiththegearandflapsdown.Therewasaminorchange in thebuffet levelas thegearand flapswere raised. Some buffet persisted and a high aerodynamic noise levelexisted until the airplane accelerated to .87 Mach number or above, atwhichtimethebuffetcompletelydisappearedandthenoisewasreducedtoatleasthalfofthelow-speedlevel.

High Speed: Pitch control during the transonic acceleration and lowsupersonicspeedrangeswasverygood.AboveMach2 itbecameevidentthattherewassomedeteriorationintheeffectivenessofthepitchcontrol.Atspeedsabove2.5Mach,theforcelevelrequiredtomanoeuvretheairplanewas excessive due to this deterioration and due to the action of the ‘g’bellows.CooperRatingof3.5.

GroundescapefromtheB-70foraircrewwasbytworoutes,throughthetophatchesoroutthroughthemaindoor-inbothcasesusewasmadeofthe‘SkyGenie’,acontrollabledescentdevice,later

usedintheNASASpaceShuttle.

Crewswerewarnedthatiftheentrancedoorwasused,theyhadtobesurethatthepippinsontheescaperopeswerefirmlyanchoredinthesocketsabovethedooropeningtoprovideproperlocation

ofthedescentdevices.

Ifthegroundescapehatchwasusedthecrewhadtomakesurethattheescaperopeswerefullyextendedoutofthehatchandovertheleadingedgeofthecanardtoprovideaproperlocationofthe

descentdevice.

FromtheSafetySectionoftheXB-70AFlightManualcomesthisdrawingofhowtheescapecapsulescouldbetowedbehindaboatintheeventofawater-landing.

Thedirectionalcontrolwasadequateto takecareof threeenginesouton one side, butwasmuch less effective in producing yaw thanwere theailerons. Considering the capability of the rudders alone, they wereconsidered adequate. Cooper Rating of 3.0. However, the powerfulcapability of the ailerons in producing yaw was considered the mostobjectionablecharacteristicintheairplane.CooperRatingof4.5.

The roll response of the airplane in the supersonic flight regimewasgood.Therollresponsedidnotseemtodeteriorateatthesamerateaspitchresponse,andthereforetherewaslesscompatibility in theresponseof theairplane between Mach 2 and 2.7 than in other areas. As the airplaneapproached Mach 3, the roll response deteriorated and the yaw due toaileroninputwasreduced;thereforethehandlingqualitiesoftheairplaneinrollwerebetteratMach3 thanatanyothersupersonicspeed.CooperRatingfortherollcontrolsystemwas3.5.

Although there were minor differences in the flight characteristicsbetween and 1.4 Mach 3 with all augmentation off, the generalcharacteristics were the same. The short-period oscillations in pitch andyawwere four tosixseconds in lengthandthedampinginpitchandyawwas relatively poor. The airplane could be flown at all speeds with theaugmentationoff,exceptthatextremecarehadtousedintheuseofaileronsbecauseofthestrongtendencytoexcitelateral-directionaloscillationswiththeailerons.Thiswasduetoahighrollrateintheunaugmentedcaseandbecauseof theexcessive levelofyawdue toailerons.When thepilots leftthe ailerons alone, the yawing oscillations would damp. Unaugmentedsupersonicflight:CooperRatingof5.0.

Visibility: The visibility with the windshield down was satisfactory.

Althoughsome forwardvisibilitywas lostafter therotationat takeoffandduringtheinitialpartoftheclimbout,theremainderofthesubsonicflightwassatisfactory.Thevisibilityforlandingwasconsideredgood.Atnotimewas thepilot awareof any loss of the runway visibility duringapproach,flare,andtouchdown:CooperRatingof3.0.

Thelongitudinaltrimsystemwasverygood-CooperRatingof2.0.Thelateraltrimsystemwasalsoverygood,exceptthattheprimarylateraltrimcontrolwas difficult to operatewith a high degree of accuracywhen thepilotwaswearingheavygloves.CooperRatingof3.0.

The directional trim system was very good after the gear had beenretracted.Itwastoosensitivewiththegeardown,whichcausedthepilottoover-controlwhenattemptingtotrimoutdirectionally.

Occasionallysomedifficultywasencounteredwhenengagingthenosewheelsteeringsystemduetotheinabilityoffindingtheneutraldirectionaltrimposition.For instance, thepilotwould trimoutdirectionallyprior toputting the gear down; however, the trim system would not be exactlycentered at this time.When the gearwas lowered, thisminor out-of-trimconditionwasamplifiedbya ratioof four toone.Due to turbulenceandlow speed flight characteristics, this out-of-trim condition would goundetecteduntilafterlandingwhentherudderswerereleasedandthenosewheelsteeringengagedwhichresultedinanabrupttransientinthesteeringsystem. It was recommended that consideration be given to reducing thedirectionaltrimrateandincorporatingarudderpositionindicator.CooperRatingof3.0.

Thecompatibilityoftherollandpitchforcegradientswassatisfactory;however,duetothelargedifferencesinthemomentsofinertia,theairplaneresponded much quicker in roll than in pitch or yaw. This was notconsideredtobeadiscrepancyagainsttheairplane,butacharacteristicofaverylongandnarrowconfiguration.Itrequiredsomegettingusedtobythepilotsinordernottoover-controlinroll,particularlywiththetipsup.Achangeshouldnotbemadein theresponsecharacteristics,butsomethingshould be done to reduce the adverse yaw due to ailerons. This wouldeliminate the primary objectionable characteristics in the airplane. If thepilots were not concerned about generating yaw with aileron inputs, thefighter-like roll response would not be objectionable. Control forcecompatibility:CooperRatingof3.0.

Thetrimchangewhileoperatingthe landinggearwasnegligible.The

trimchangewhileoperatingthewingtipswassmallandoccurredatsuchaslowratethatitwashardlynoticeabletothepilotsincehetookcareofitinthenormal trimmingof theairplane.The trimchangedue tooperationoftheflapswaslarge,buteasilymanageablewiththetrimsystem.Althoughthe trim system did take care of the trim change, when the flaps werelowered thecontrolcolumnmovedverynear the forwardendof its travelleaving very little usable down elevon for manoeuvring, go-around, orflying in turbulent air. This could be extremely hazardous in the instancewherethecenterofgravitywasfartheraftthannormal.

Evenallowingforlensdistortion,thenoseoftheXB-70Awaswayaheadofthenosewheel.(USAF)

AnunusualviewoftheXB-70initsparkingbayatEdwardsAFB,surroundedbyancillaryequipment.(USAF)

Itwasrecommendedthatadesignchangebemadewherebymoredown

elevoncontrolwouldbeavailablewithflapsdown.

ToMach3-andbeyond!AirVehicle1onlyevermanagedtostruggletojustoverMach3once-andthatwasonlyforaprecioustwominutes.

Thefirsttrue,sustainedMach3flightwasflight39ofAV/2on19May1966,whenAlWhiteasAircraftCommanderandCottonasSecondPilotreached3.06Machforthirtythreeminutes.

As usual, for certain stages of the flight the Valkyrie was escorted -Chase One was Capt Hoag and DeLong in T-38 ‘598’. Chase Two wasCaptainLivingstoneaboardF-104‘817’.FlyingsupportwasLt.ColFultonandPrahlinB-58‘662’.RescuewasC-130‘132’flownbySqnLdrDavidCretney(onexchangefromtheRoyalAirForce)andMajorDoryland.Theflightwastolastonehourfifty-nineminutes.

Astheflightreportstated,thepurposeoftheflightwasMach3for30minutes!

PreflightandTaxiThe preflight and engine start phases were completed by 08:14. It wasnecessary to make a soft start on the #1 engine. Although this was notwritten up as a discrepancy, soft starts have been necessary for the lastthreeenginestarts.

Anoilleakwasdetectedfromtheengine4podvent.No.4enginewasacceleratedto90percentrpmforashorttimeandonreducingpowertoidle,theleakhadstopped.Nofurtheractionwastaken.

Datawastakenforthepoweradvancesrequiredduringthetaxiphase.Nobrakechatterwasencounteredatanytimeonthisflight.

Takeoff,ClimbandCruiseBrakes were released for takeoff at 0900 and MAX afterburner wasimmediately selected. OVERSPEED was not used for this takeoff. Therunway temperature was reported to be 69° at brake release. Theaccelerationcheckwasmadeusingthesensitiveairspeedindicatoronthepilot’s side. According to the handbook, the airplane should haveacceleratedfrom70to148knotsin20seconds.Itactuallyacceleratedfrom70knotsto150knotsin20seconds.Rotationstartedat195knots,andtheairplane flew off the ground at 210 knots on the pilot’s tape airspeed

indicator.

‘Goinsidethedoorandturnleft...’Thisistheviewthatgreetsyoufromthetinyislebehindthecrewcompartment-thecockpitofAirVehicleOneasitwasin1991.Thespacebetweenthetwoescape

capsulesisverytight.(Author)

The gear and flaps were raised. The #2 utility augmentation channeldisengagedduringthegearcycleandwasimmediatelyre-engagedafterthegearwas up and locked. The tips were lowered to one-half at 300 knotsduring the climb. At 0.9 Mach the AICS was reset and switched to theAUTO node. The first turnwasmade at 32,000 ft. fiftymiles east of theEdwards TACAN. The airplane did not accelerate during the turn;consequently, it did not go supersonic until the turn was completed. Thewindshield was raised for the acceleration and the airplane wasaccelerated at 32,000 ft. to 575 knots where the climb was continued.

During the initialpartof theclimb, thespeedwasallowed tobuildup to595knotsandthenslowlybledoffto575by40,000ft.

The inlets started between 2.13 and 2.16Mach just prior to reaching50,000ft.intheclimb.Afteracceleratingto2.6Mach,lightbuffetingwasobserved in theairplaneof the typeencounteredonprevious flightswhenthebleedairholeswerepartiallyplugged.However, thisbuffetingallbutdisappearedby2.7Machandwasnotnotedagainduringtheflight.

Both thepilotandcopilothad trouble in theclimbphaseof this flightwiththefaceplatefoggingover.Thepilotnormallyrunstheheaterrheostatatthemidposition,buthaditonfullhotandwasstillgettingsomefogging.Thecopilotreducedtheairflowthroughtheeyeballoutlets toaminimum,and then turned the cabin heat up one notch in an attempt to help thissituation.Laterintheflightwhenthetemperaturewasup,neitherpilothadtroublewiththefaceplatefogging.Whateverthecause,itappearsthattheface plate heating units are not adequate to take care of the moistureexpelledinthehelmet.

The turn north of Lovelock, Nevada, was made at approximately 2.6Mach,andupuntil that time theTACANindicationswereverygood.TheDMEfunctionoftheTACANbrokelockjustbeforetheturn,sothegroundstationadvised thepilotof the turningpoint.Afterrollingoutof the turn,the TACAN locked on Lake View TACAN station and appeared to befunctioning satisfactorily, but the heading information drifted and fooledthe pilot into thinking that hewas left of coursewhen actually the radartrackshowedhimtoberightofcourse.TheTACANworkedverywell forthe remainder of the flight. Any errors in navigation were caused by thedriftingandthesluggishnessoftheheadinginformation.

Thepilot’sposition,withPILOTXB70and20001stenciledonthesideofthecapsule.Itwasremarkablydifficulttoseearoundinsideduetothelackoflighting-Ionlyreallysawtheinterior

whenIviewedmyphotographslater!(Author)

TheinletsystemwasswitchedtoHIGHPERFORMANCEat2.7Mach.The turnnortheastofBoise, Idaho,wasmadeat2.8Machusinga15- to17-degreebankangle.Theairplanedidnotaccelerateinthisturn.

During the runbetweenapointnorthofDuBois toRockSprings, theairplane was slowly accelerating, but the throat Mne were on the lowerlimit.At2.9Machthedeviationcontrolwassetto000fortherightinlet.At2.92thesettingwaschangedto995.At2.97theleftinletdeviationcontrolwassetto000.Mach3indicatedwasachievedat0959atapointinaturnjustsoutheastofRockSprings,Wyoming.

Totalfuelremainingatthattimewas81,000pounds.ThethroatMachnumbersindicated3.06ontheleftand3.02ontheright.Consequently,therightdeviationwaschangedto990.Duringthenexttwominutes,theMachnumberbuiltupto3.025andthenbledoffto3.01astheairplaneclimbedabove71,000ft.ThroatMachnumberswere3.05ontheleftand3.04ontheright.Thedeviationsettingswerethenchangedto995ontheleftand985ontherightandremainedthatwayfortherestoftheMach3portionoftheflight. The Mach number varied between 3.02 and 3.06 with severalconstant periods at 3.03. Altitude variations ranged between 70,500 and72,500ft.Itisthepilot’sopinionthatthealtitudevariationswerecausedbyveryminorerrorsinpitchattitude,ratherthananyabruptpressurechangesintheatmosphere,Thealtitudechangeswerenotsudden;however,therate-of-climb instrument showed some rather large excursions occasionally

duringtheflight.

TheSecondPilot’ssideofthecockpit,showingthemixtureofrotaryandlinearor‘strip’instrumentation.ThecentreofthecontrolhornshasanoutlineoftheValkyrieshowingthelocation

ofthefueltanks.(Author)

Thecentralpedestalareaofthecockpit,theouterareaofwhichhingesuptoallowbetteraccesstotheseats.(Author)

ArightturnwasstartedatPrescott,Arizona,andtheairplanewasheldin a 15-degree bank. The flight path at the beginning of the turn wasapproximately tenmileswest of the planned flight path, and the airplaneovershottheplannedflightpathbyapproximatelyfiftymilesonarrivingintheEdwardsarea.Noproblemwasencounteredinmaintainingspeedintheturn,althoughaltitudecontrolrequiredintensepilotconcentration.

ThethrottlesettingsduringtheMach3runvariedbetweena92-degreethrottleangleandMAXafterburner.During theearlypartof the run, theaveragethrottlesettingwasapproximatelyninety-eightdegrees.Duringthefinaltenminutes,theaveragethrottlenettingwas95degreesorless.

Thepilotwasawareoftheminortrimchangescausedbyfuelburningout of tank 8 and tank 1. In otherwords, the pilot could sense the pointwheretank8stoppedfeedingandtank1beganfeedingduetotheshift intheCG.Thishasaminoreffectontheprecisealtitudecontrol,sinceonlyminor pitch trim changes will cause rather large changes in the rate ofclimb.

A marker was placed on the data at C/N 5688 with a call-out forcorrelationwiththegroundstationsatEdwardsduringthelastfiveminutesoftherun.Afteratleast32minutesatMach3,theinletswereswitchedtonormalandthedeviationcontrolssetat005.Beforethepilotcouldreducethe throttle to Military Power, the left inlet unstarted. It restartedimmediatelyandthecopilotresettheduct.

At approximately this time the right inlet unstarted and went intoseveral cycles of buzz. The copilot selected LOW PERFORMANCE; buteventhoughtheairplanewasbuffetingmoderatelyduetotheinletsettings,thebuzzlightsventoutandtheside-to-sideoscillationassociatedwithbuzzceased. TheVIBRATIONHIGH light cameonwith no indication of highvibrationonanyofthetwelvepickups.

MilitaryPowerwas selected and the deceleration commenced.As theairplanedeceleratedthrough2.6Mach,theleft-hand#1buzzlightcameonwithnoairplanetransient.Thisoccurredseveral timesduringthedescenttoMach2.

At approximately 2.2Mach number, in a right turn near Bishop, thewindshield was lowered. Total fuel at this timewas 26,500 pounds. At aspeed justbelowMach2, the#6engineEOTsuddenly increased to1000degrees. The throttle was reduced to IDLE, eliminating the over-temperature condition. At .7 Mach number it was noted that the utilitypumpstatuslightswereonforutilitypumps1,3,4and5.Atapproximately1.2Mach,the#1enginenozzlepositionindicatorbecameinoperativeandbegantospincounterclockwise.Justaftergoingsubsonicwithengines#1,#3, #4, and #6 at IDLE, the #3 engine compressor vibration pickupwasindicating60percent.Thethrottlewasincreasedto80percentrpm,whichreduced the vibration to 40 per cent. The #2 enginewas then reduced to

IDLEforthedescent.

APPROACHANDLANDINGThe normal descent was made to a straight-in final approach. Whileturningonfinalapproachafterhavingloweredthegearsatisfactorily, theflapswerelowered.TheflapscamedownandthenslowlystartedbackupagainwiththeflapswitchintheDOWNposition.Flapswereraisedontheapproach and a no-flap landing was made. Touchdown occurred atapproximately170knotsonthepilot’sVSI.Twochutesinflatedandbrakingwas satisfactory. After turning off the runway, during theMilitaryPowerruns, itwasnotedthat the#4nozzlehadfailedopen.The#4engineEOTindicatedonly500degreesatMilitaryPowerthrottlesetting,andthenozzlepositionwas70percent.

Anotherviewofthecentralareaoftheinstrumentpanel,plusmoredetailsofthefirstpilot’ssidethatincludesdetailsofthecentreofhiscontrolhorns.(Author)

BehindthecrewcabinofAV1istheenvironmentalcontrolsystemcompartment.(Author)

SUMMARYThis flight shouldhaveremovedalldoubtabout theXB-70’scapabilityofaccomplishing itsobjectives.Although somedifficultywas encountered inacceleratingatthenorthernendofthecourse,onceMach3wasachieveditwasnoproblemmaintainingthespeed,evenintheturns.

Itwasapparentfromthisflightthattheautomaticinletsystemhasnotbeenfullydeveloped.EvidentlymoredataatMach3isrequiredtooptimizethis system so that the co-pilot isn’t required to manually adjust theautomatic schedule so many times in order to satisfactorily complete amission.Sincethisisoneofthemostimportant,ifnotthemostimportant,newsystemintheairplane,itwouldbeverybeneficialtoschedulesufficientflying at Mach 3 to overcome this deficiency; in fact, this is stronglyrecommended.

DISCREPANCIES1.Yawaugmentation-#2disengagedseveraltimesduringflight.2.Pilotandcopilotfaceplateheatinadequate.3.#6enginewentovertempatMilPowerduringdescent.4.#1enginenozzleindicatorspinningduringlastportionofflight.5.Flapswentdownandthenslowlybleduponfinalapproach.6.#4enginenozzlestuckopenonMilPowerrunafterlanding.7.VIBRATIONHIGHlightonafterunstart.IndividualreroutewereO.K.

BLACKBIRDSANDSUKHOIS

OvertheyearstherehasbeenmuchspeculationthattheXB-70programmewas secretly assassinated by Lockheed and Kelly Johnson with their A-12/YF-12andRS-71programmebyputtingpressureontheOvalOffice.

Likemanyconspiracytheories,mysteriestendtoconcealhalf-lies,half-truths. Throw into that mix a large dose of political intrigue, numerous‘black’ projects and the Alice in Wonderland world of the CentralIntelligenceAgency, andeven today,youhaveverymurkywaters indeedthatprovehardtoseethrough.

Hereisasgoodaplaceasanytodispelsone‘urbanmyth’.TheSR-71designatorisactuallyacontinuationofthepre-1962bomberseries,whichended with the B-70 Valkyrie. As we have already seen, the B-70 wasproposedforthereconnaissance/strikerole,withanRS-70designation.The‘RS’ prefixwas allowed as an explicit ‘special case’ in the original 1962issueofthedesignationregulations.WhenitwasclearthatLockheed’sA-12aircraft(thenusedbytheCIA)hadmuchgreaterperformancepotential,itwasdecidedto‘push’aUSAFversionofthatoneinsteadoftheRS-70.ThisUSAFversionwastobecometheRS-71.

Conventional wisdom now says that President Lyndon B. JohnsonmessedupthedesignationinhispublicannouncementandcalledittheSR-71-andnobodywantedtocorrectthePresident.Becausethestrikemissionhad been cancelled anyway, ‘SR’ was quickly reinterpreted as ‘StrategicReconnaissance’.However,afirst-handwitnessofthoseeventsrevealedinAviationWeek&SpaceTechnology,thatLBJdidnotmisreadanything.Infact,USAFChiefofStaffLeMaysimplydidn’tlikethe‘RS’designator-healreadyobjectedtoitwhentheRS-70wasdiscussedfortheinferencewasthat the prime mission was ‘Reconnaissance’ not the ‘Strategic’ aspect -LeMay preferred the ‘SR-70’.When theRS-71was to be announced, hewantedtomakesureitwouldbecalledSR-71instead.HemanagedtohaveLBJ’s speech script altered to show ‘SR-71’ in all places.Using archivedcopiesofLBJ’sspeech,itcanactuallybeverifiedthatitreadsSR-71bothin thescriptandon the tape recording.However, theofficial transcriptof

thespeech,createdfromthestenographicrecordsandhandedto thepressafterwards, shows ‘RS-71’ in threeplaces. It seems thatnot thePresidentbut a stenographer did accidentally switch the letters, and thus create afamousaviation‘urbanlegend’.

Inmanywaysitishardtocomeupwithaconcrete‘link’betweentheA-12/YF-12/SR-71familyandtheB-70.TheLockheedmachineswerenotdesigned to perform the same functions as the North American design,despitestridentattemptsbysomemembersoftheAirForceandpoliticianstocastthembothinthesamemould.

There were major differences in their construction and operation, aswellastheirperformance.TheB-70wasdesignedasastrategicbomber.Itwasnever intended tobe stealthy. Itwasnotdesigned for reconnaissancework - although the Air Force tried to sell the reconnaissance role toCongressatonepoint inanattempt tosave theprogrammeas theRS-70.The B-70 was never intended to be anything but a high-altitude,intercontinentalstrategicbomberwithMach3capability.

However, that said, therewere a lot of similarities.Both programmeshad difficulty building out of materials that could withstand the hightemperaturesassociatedwithhigh-speedflight.At80,000-feetaltitude,theambientairtemperaturewasaroundminus60°F,butat2,000milesperhourthe skin temperature would approach 600°F. Each programme found adifferentsolutiontothisproblem.

ClarenceLeonard‘Kelly’Johnson(27February1910–21December1990)

Development of the XB-70 brought about the first extensive use ofstainlesssteelhoneycomb,butonlyafternewautoclavesweredesignedto

support the large sizes required. A new brazing technique had to bedeveloped to make sure that the ‘weld’ would not be compromised byvibrationorheat.Someof theconstraints includedwearingspecialglovesso thatnaturaloils from theworkers’ fingerswouldnot interferewith theintegrityoftheweld.

Kelly Johnsonwaswell aware of the problemsNorthAmericanwerehaving.Hewasquotedassaying,withafineelementofsarcasm‘...Itwasevident very shortly that the SkunkWorkswas not smart enough tomakeuse of steel honeycomb with its very involved and precise tooling anddifficultiesinqualitycontrol’.

Nevertheless,Lockheedwas having similar problemswith theA-12 -codenamed‘Oxcart’-anditsexotictitaniumskin.Althoughitwasasstrongasstainlesssteel,titaniumwasalargelyuntriedmaterial,particularlyinthequantitiesusedintheA-12.

BothLockheedandNorthAmericanmadeuseofheatsinktechnologyto handle some of the airframe heat loads and in both cases the primaryonboard heat sink was fuel. In the A-12, the airframe was largelyuninsulated, and though it used heat-resistant titanium, some of the heatwasabsorbedbythefuel.Fuelalsowasactuallyusedasahydraulicfluidfortheenginecontrols.Thecockpitwaspressurized,butnotwellinsulated,so the pilot had to wear a pressure suit at all times for temperatureprotectionaswellasprotectionagainstsuddendepressurisation.

The XB-70 was a much larger aircraft and carried an enormous fuelload,whichmadeforaverysuitableheatsink.Inaddition,theXB-70wasinsulated, aided further by the honeycomb skin. The crew compartmentcouldbekeptatarelativelycomfortabletemperature,andthelargervolumeof pressurized space within the aircraft meant that any depressurizationwould be more gradual. The crew of the B-70 could, in theory at least,operateina‘shirtsleeve’environment.

Weightandpayloadperformancedifferedgreatlybetween theOxcartsand the Valkyrie. The B-70 was designed to carry a heavy, destructivepayload from the onset that the Oxcarts could never match. The extrapayloadabilityoftheB-70wasalsoutilizedforfuel.TheB-70hadalongerunrefueledrangethantheOxcarts,andtheB-70couldtakeoffwithafullfuelload.TheOxcartshadtorefuelshortlyaftertakeofftoenablethemtoreachoperationalspeedandaltitude.WeightwasalwaysaproblemfortheOxcarts,andtheywrestledwithitonacontinuingbasis.

Certainly there are many indications that Lockheed and NAA wereawareofeachother’sprojectsandhelpedwheretheycould.Johnson’slogprovidesnumerousinstances.‘12March1962:ItappearsthatourproblemwithVironshowsthatthematerialplannedfortheB-70isnogoodeither.SentinformationandacanofoursealanttoWrightFieldforusebyAscanito help theB-70’. 5December 1962: ‘...We are helping theB-70 allwecan,becausetheyareinrealtroubleontanksealingandwiringandotherthings.IwroteGeneralAscanialetterpromisingourassistance,whichwehavegivenverballymanytimesinthepast’.14August1964:‘FredRailofASD and EdDawson of North American came here to discuss hydraulicproblemsontheB-70.1amamazedtofindtheybuiltnohydraulicmock-upwhatsoever and they are into troubles that we solved in 1961. I showedDawsonaletterIhadwrittentoGeneralAscaniin1961,pointingouttheseproblems.’

TheOxcart’sfuelrequirementcalledforlow-vapour-pressurefuelwithalowvolumeatoperatingtemperatures;thefuelwouldalsobeaheatsinktocoolvariouspartsoftheaircraft.TheJ58enginerequiredlubricantsthatdidnotbreakdownatveryhighoperatingtemperaturesofMach3.2speeds.Finding a suitable hydraulic pump was just as difficult. Kelly JohnsonfinallymodifiedapumpthatwasbeingdevelopedfortheNorthAmericanB-70.

Therewerealsooperationaldifferencesbetweenthetwoaircraft.TherewasnoquickturnaroundsystemdevelopedfortheA-12.Ittookaminimumof three hours of preflight to get theA-12 into the air. It also required aspecialstartcartwithtwinBuickautoracingenginestogettheJ-58enginesuptothe3,000rpmneededtostart.

TheB-70would be able to start up via one engine and an alert pod,whichwassimilartoastaircartbutphysicallyattachedtotheenginebay.ForacombatoperationalB-70onalert status, itwassupposed to takenomorethantwominutesfromstartuptorunway.Fromacoldstartitwouldtakeonly20minutes.Thequick start featurewasnever tested in the twoXB-70sbecause theywerenot intended tobecombatoperationalaircraft,buttheprocedureswereinplacefortheproductionmodel.

Aircraftoperationsaside,programmeoperationsweredifferentaswell.TheA-12washighlyclassifiedandtheB-70wasnot.Publicityforthetwoprogrammeswas a double-edged sword and they each handled it in theirown way. Publicity was not a problem for the B-70 programme. The

futuristicbomberwasinthemedia’sspotlight,andboththeAirForceandNorthAmericanbasked in it,particularlyearlyon in theprogramme.TheB-70 received considerable attention in the national news, aviationmagazines,andotherpublications.Whilesomeaspectsofitwereclassified,it was certainly not a ‘black’ programme, so money was saved by notkeeping it secret.On theother hand, lackof secrecymeant that theB-70programme was fair game for budget-cutting politicians. Conversely, theOxcarts had to live in deep secrecy. They lost out on the benefit of themedia, but avoided budget cuts, as most politicians did not know theyexisted.

AnA-12‘Oxcart’takestotheskies.(SimonPetersCollection)

Toseethewayforward-wehavetolookbackIn the early 1950s, with ColdWar tensions on the rise, the US militaryrequired better strategic reconnaissance to help determine Sovietcapabilitiesandintentions.Theexistingsurveillanceaircraftwereprimarilyconverted bombers, vulnerable to anti-aircraft artillery, missiles, andfighters. Itwas thought an aircraft that could fly at 70,000 feetwouldbebeyond the reachofSoviet fighters,missiles, and even radar.Thiswouldallow‘overflights’-knowinglyviolatingacountry’sairspacetotakeaerialphotographs.

Underthecodename‘Aquatone’,theAirForcegavecontractstoBellAircraft, Martin Aircraft, and Fairchild Engine and Airplane to developproposals for the new reconnaissance aircraft. Officials at LockheedAircraft Corporation heard about the project and asked aeronauticalengineerClarence‘Kelly’Johnsontocomeupwithadesign.Johnsonwasabrilliantdesigner,responsiblefortheP-38Lightning,andtheP-80.Hewasalso known for completing projects ahead of schedule, working in aseparate division - AdvancedDevelopment Projects - jokingly called the

Skunk Works after the striking black and white carpet in their entrancefoyer.

Johnson’sdesign,calledtheCL-282,marriedlongglider-likewingstothefuselageofanotherofhisdesigns,theF-104Starfighter.Tosaveweight,his initial design didn’t even have conventional landing gear, taking offfrom a dolly and landing on skids. The design was rejected by the AirForce, but caught the attention of several civilians on the review panel,notablyEdwinLand, the father of instant photography.Landproposed toCIA director Allen Dulles that his agency should fund and operate thisaircraft.After ameetingwithPresidentEisenhower,Lockheed received a$22.5millioncontractforthefirst20aircraft.ItwasrenamedtheU-2,withthe‘U’referringtothedeliberatelyvaguedesignation‘utility’.

ANACAregisteredbare-metalU-2ispreparedforflight..(SimonPetersCollection)

Ablackpainted,civilianregisteredU-2.(SimonPetersCollection)

The first flight occurred at the Groom Lake test site (Area 51) on 1August1955,duringwhatwasonly intended tobeahigh-speed taxi run.Thesailplane-likewingsweresoefficientthattheaircraftjumpedintotheair at 70 knots. Project director Richard M. Bissell assured PresidentDwight Eisenhower that the aircraft’s high altitude of 70,000 feet wouldrender it invisible to Soviet radars. However, the earliest flights, in July

1956,weretracked.On5July,anA-100radardetectedCarmineVitoasheflewoverSmolensk,enroutetoMoscow.Theoperatorsevencalculatedhisaltitude as 65,000 feet, which was later rejected by experts who did notbelievethatanaircraftcouldflythathigh.

Hartford, Connecticut-born Richard Mervin Bissell Jnr had workedcloselywith theOffice of Strategic Services (OSS),which had helped toorganizeguerrillafighting,sabotageandespionageduringWorldWarTwo.InJuly,1947BissellwasrecruitedbyAverellHarrimantorunacommitteetolobbyforaneconomicrecoveryplanforEurope.Thefollowingyearhewas appointed as an administrator of theMarshall Plan in Germany andeventuallybecameheadoftheEconomicCooperationAdministration.

Bissellworked for theFordFoundation for awhile butFrankWisnerpersuadedhim to join theCentral IntelligenceAgency (CIA). In 1954hewas placed in charge of developing and operating the Lockheed U-2.WithintwoyearsBissellwasabletoclaimthat90%ofallhardintelligenceabout theSovietUnion coming into theCIAwas ‘...funneled through thelens of the U-2’s aerial cameras’. This information convinced PresidentDwightD.EisenhowerthatNikitaKhrushchevwaslyingaboutthenumberofbombersandmissilesbeingbuiltbytheSovietUnion.

RichardMervinBissell,Jr.(18September1910–7February1994)

Inmid-August,Bissellassembledagroupofadvisorstobeginworkonsolving the tracking problem. Under the title ‘Project Rainbow’ the CIAfundeda researchprojectaimedat reducing the radarcross sectionof the

U-2 to reduce thechance that itwouldbedetectedand trackedbySovietradarsduringitsoverflightsoftheUSSR.

Withtheeventualfailureof‘ProjectRainbow’,Bissellinitiated‘ProjectGusto’ - and so preliminarywork began inside Lockheed in late 1957 todevelopa follow-onaircraft tooverfly theSovietUnionandbe ‘stealthy’enoughtoavoidradardetection.Theywerealsointendedtobefastenoughto avoid interception if they were located. The designs were nicknamed‘Archangel’,aftertheU-2programme,whichhadbeenknowninternallyas‘Angel’. As the aircraft designs evolved and configuration changesoccurred, the internalLockheeddesignationchanged fromArchangel-1 toArchangel-2, and so on. These nicknames for the evolving designs soonsimplybecameknownas‘A-1’,‘A-2’,etc.TheA-12wasLockheed’s12thdesign in this development of the U-2. Many internal documents andreferences to individual aircraft designs used Johnson’s preferreddesignation,using theprefix, ‘theArticle’ for thespecificexamples.ThusontheA-’sfirstflight,thesubjectaircraftwasidentifiedas‘Article121’.

In1958AllenDullesappointedBissellastheCIA’sDeputyDirectorforPlans (DDP), replacing Frank Wisner, who had suffered a mentalbreakdown.RichardHelms stayedonasBissell’sdeputy.TheDirectoratefor Plans reportedly controlled over half the CIA’s budget and wasresponsible forwhat became known as the CIA’s BlackOperations - themurkyworldof ultra-secret operations andprojects.Althoughnot part ofthis story, it is worth noting that the DDP oversaw plans to overthrowJacoboArbenzGuzmán,PatriceLumumba,RafaelLeónidasTrujillo,Abdal-Karim Qasim, Ngo Dinh Diem, and others. Bissell’s main target wasFidelCastro,whicheventuallysurfacedwiththeBayofPigsoperation.InSeptember1960BissellandDullesinitiatedtalkswithtwoleadingfiguresoftheMafia,JohnnyRoselliandSamGiancana.Later,othercrimebossessuch as Carlos Marcello, Santo Trafficante and Meyer Lansky becameinvolvedinthisfirstplotagainstCastro.TheMafiawereknowntobeangrywithCastroforclosingdowntheirprofitablebrothelsandcasinosinCuba.If the assassins were killed or captured the media would accept that theMafiawereworkingontheirown.TheMafiaplayedalonginordertogetprotectionfromtheFBI.

Meanwhile,backatTheRanch,in1959theCIAselectedtheA-12overaConvairproposal.Then,on26January1960,theCIAordered12A-12s.AfterselectionbytheCIA,furtherdesignandproductionoftheA-12took

placeunderthecode-name‘Oxcart’.After development and production at the Skunk Works, in Burbank,

California,thefirstA-12wastransferredtoGroomLaketestfacility,whereon 26 April 1962, Lockheed test pilot Lou Schalk took the A-12 on itsshakedownflight.Thefirstofficialflightoccurredon30April.Onitsfirstsupersonicflight,inearlyMay1962,theA-12reachedspeedsofMach1.1.

ThefirstfiveA-12s,in1962,wereinitiallyflownwithPratt&WhitneyJ75 engines capable of 17,000 lb thrust each, enabling them to obtainspeeds of approximately Mach 2.0. On 5 October 1962, with the newlydeveloped J58 engines, theA-12 flewwith one J75 engine, and one J58engine.Byearly1963, theA-12was flyingwith J58engines, andduring1963theseJ58-equippedA-12sobtainedspeedsofMach3.2.

Tryingtofindanyharddetailsaboutwhathappenedisnoteasy-intheworldof‘black’projectstryingtogetholdoffactsisliketryingtograbaholdofmist. It seems that theCIA thought its starwasverymuch in theascendancywiththesuccessoftheU-2andtheup-comingA-12/YF-12/RS-71project.Politicallyitseemedagoodmovetoadvanceitsownstatusbylatchingonto thesuccessof theSkunkWorks. In theCIA’seyes, theCIAcould do no wrong, and working ‘in the black’ appeared to be a cost-effective way to go. There is a good possibility that Bissell saw theproposed RSB-70 as a possible high-cost public threat to their own A-12/YF-12/RS-71‘black’project.

ThesetwoviewsofthemissilebaysintheYF-12.

Themissilebaydoors,alongwithalmostalloftheairframewasmadefromtitaniumalloy.

Thesepicturesgivesomeimpressionofwhatthebomb-bayareaoftheRB-12-acompetitortotheB-70-couldhavelookedlike.(Lockheed)

One person ‘whowas there’ as itwere,wasBenjaminR ‘Ben’Rich,whowasKelly Johnson’s righthandman, and laterheadedup theSkunkWorksfrom1975untilhisretirementin1991.Hisbiography‘SkunkWorks’appearedin1994,justbeforehediedin1995.Richwaspresentatmostofthemeetings,butsomehowdescribestheminaslightlydifferentmannertoalmosteveryothersource.

Certainly it is true that the A-12 design was modified into the long-range interceptor AF-12 by the Skunk Works engineering team,incorporating a fire control system integrated with a Hughes radar. Asecondseatintheoriginalsensorsystembaywasaddedtoaccommodateafirecontrolsystemoperator.

ConcurrenttotheactivityontheAF-12,abomberversionoftheA-12,referredtoas theRB-12,alsowasbeingstudied.Aforwardfuselagefull-scalemock-uphadbeencompletedandonJuly51960alongwiththeAF-12mock-up,wasreviewedbyGeneralsCurtisLeMayandThomasPower.The two found themock-ups of considerable interest and asked if eitherconfiguration could be modified to carry a terminal radar or an air-to-groundmissile.

LeftisBenjaminRobert‘Ben’Rich(18June1925–5January1995)alongwithhismentorKellyJohnson.TheyarebothposedinfrontofanewbuildU-2,afterKellyJohnson’sretirement.

(Lockheed)

Kelly Johnson responded by stating, ‘...we could do this within theaerodynamicconfigurationoftheA-12and,forthejobthattheyoutlinedtodo,whichwastoplaceamissilewithin200feetofatarget,onecouldnotargueabouttheuseofaguidedmissileratherthanoursimplerapproachintheRB-12report’.Thiswasareferencetotheuseofconventionalfree-fallbombs.

The RB-12 study had resulted from the then recent development ofsmall, high-yield nuclear warheads. Johnson, in an RB-12 proposal, hadnotedinhislogthattheaircraftcouldresult ina‘...verypowerfulstrikingforce... with little or no weight or space penalty...’ to the aircraft. Fourhypothetical 400 pound bombs based on the new warheads, or a singlePolaris-sized warhead could be accommodated in a fuselage bomb baywhileretainingthesamefuelloadasthereconnaissanceA-12.Onedesignstudy showed theRB-12 fittedwith a rotary bomb bay.No aerodynamicchanges were required and the radar attenuating features of the aircraftcould be retained. The latter, coupled with the aircraft’s performance,almost certainlywouldmakechancesofdetection close tononexistent. ItseemsthattheRB-12wasintendedasa‘clean-up’vehicletobeusedafteran initial ICBM strike, targeting command posts, air bases,missile sites,submarinepensandSAMsites.

Johnson noted in his daily log that, ‘While Hughes was giving apresentationonasimplifiedair-to-groundweaponsystem,LeMaytookmeby thearmandwewent toanotheroffice.He toldmethathewasn’tverysurethattheRB-12wouldbecomeamodel,buthefeltsure‘wewouldgetsomefighters’.Iaskedhim,‘whataboutreconnaissanceairplanesliketheA-12?’andheseemedsurprisedthattheAirForcewerenotgettingany.HemadeanoteonayellowpaperpadandaskedmehowsoonwewouldhavetoknowaboutA-12s tocontinueourproduction. I toldhimwithin two to

threemonths’.Ben Rich described things slightly differently: ‘...LeMay suddenly

raised his hand as a signal for Kelly to stop talking. Then he stood up,grabbedKelly by the arm, and led him to the far corner ofKelly s hugeoffice for a private, whispered conference that lasted nearly tenminutes,while the rest of us sat transfixed, watching these two titans of militaryaviationcookingupsomesortofschemeorscenario.

Kelly told us later that LeMay was enthusiastic about using theBlackbirdas an interceptor but resisted the ideaof using it as a bomber.TheB-70wasstillverymuchonhismind.‘Johnson,Iwantapromiseoutofyou that youwon’t lobby anymore against theB-70’..Kelly agreed—apromise he would deeply regret in the years ahead. ‘We’ll buy yourinterceptors.Idon’thaveanumberyetbutI’llgetbacktoyousoon’.

Kelly asked, ‘What about the reconnaissance aircraftwe built for theagency?Can’ttheAirForceuseany?’LeMaylookeddismayed.‘Youmean,wehaven’torderedany?’HewroteanotetohimselfandpromisedKellyhewouldforwardanAirForcecontractforthetwo-seaterversionofthespyplanewithinafewweeks.

TheRB-12programmewouldnot reach thehardware stage.Thiswasnotasaresultoflackofcapability,butratherbecauseitwasathreattotheon-goingNorthAmericanXB-70AValkyrie-aprogrammethatwasseentohaveconsiderablepoliticalcloutandoneonwhichtheAirForcehadhungitshatforaBoeingB-52replacement.Surprisingly,asnotedon26October1961, Johnson discovered the Department of Defense found the RB-12moreinterestingthantheAF-12.Henoted,however,‘TheAirForce,fromLeMaydown,dowanttheAF-12.’AsJohnF.Kennedywassworninasthe35thPresidentatnoononJanuary20,1961this issomeninemonths intotheKennedyPresidency.

Over the years, reported ‘gossip’ seems to indicate that PresidentKennedy asked Richard Bissell, who was listed as ‘Secretary to thePresident’ifKellyJohnsoncouldconverttheA-12intoanintercontinentalbomber - Bissell is supposed to have replied that this was exactly whatJohnson intended to do.Bissell’s answer to thePresidentwas supposedlyyes,andthispromptedKennedytoask-‘...ThenwhydoweneedtheXB-70program?

BenRichshedsmorelightonit,fromadifferentperspective:‘ButthenDickBissellgotintotheact.BissellbriefedPresidentKennedyontheCIA

Blackbird project and told him the spy version of the airplane would beoperationalinlessthanayear.Whenhelearnedhowfastandhowhighitwouldflythenewpresidentwasastonished.HeaskedBissell,‘CouldKellyJohnsonconvertyourspyplaneintoalong-rangebomber?’

BissellrepliedthatKellyaimedtodopreciselythat.‘Thenwhyarewegoing ahead with the B-70 program?’ Kennedy asked. Bissell shrugged.‘Sir’ he replied, ‘thats a question more properly addressed to GeneralLeMay’.

The President nodded sheepishly. But Kelly was embarrassed byBissell’sindiscretion.Ashenotedinhisprivatejournal,‘Bissellrecountedhis conversation about a bomber version of the Blackbird with thePresident. It was not right. The President asked for our proposal for thebomberbeforetheAirForcehadevenseenoneandIfeltobligatedtorushtoWashingtonandpresentitasquicklyaspossibletoourAirForcefriendsandshowedtheproposaltoGen.ThomasWhite.Lt.Gen.BernardShrieverwasthereandtheywereallveryupset,aswasGen.LeMay,aboutlosingB-70s to our airplane. But at least they fully understood that was not mydoingandtheycannotcontrolDickBissell’sapproachtothePresident’.

Aheadonshotif‘Habu’thenicknameappliedtotheLockheedSR-71.

Ahabu(pronounced‘hah-BOO’)isavenomoussnakefoundonOkinawainsoutheastAsiawheretheSR-71wasbased.(SimonPetersCollection)

Sodespite thedifferingviewpoints,bothsuggest thatBissellhadbeenmanoeuvringbothsidesfortheoverallbenefitofhimselforTheCompanyinordertoscorepoliticalpoints.Ifthatwasthecase,thenitwasnotKellyJohnsonandtheSkunkWorksthatproposedthedemiseoftheB-70,itwas

Bissell.KellyJohnsonalwaysmaintainedthatthefinalcancellationoftheB-70programmewasnothisideabutthatofRichardBissell.

In some respects it looks as ifBissellwasusing theLockheedSkunkWorkstobuildupasecretreconnaissance,fighterandbomberairforcejustforCIAuse.However,Bissellsoonafterwardsfoundhimselfoutofpowerbecause of his part in the ill-fated Bay of Pigs invasion of Cuba thathappened 15-30 April 1961, so his conversation with the President overcancellingtheXB-70programmusthaveoccurredbeforeBissellfellfromgrace. Not much later, Kelly Johnson, feeling pressure from RobertMcNamara, began to harbour some cancellation concerns of his own.Johnsonwasafraid thatwithBisselloutofpower,McNamara -whowasnicknamedby some as ‘Mac theKnife’ -would, in a cost-cutting frenzy,canceltheveryexpensiveandverysecretOxcartprogramme.

ASovietequivalent?OvertheyearsclaimshavebeenmadethattheRussianscameupwiththeirownversionoftheB-70-theSukhoiT-4,‘Aircraft100’,‘Project100’,or‘Sotka’,whichevernameyoucaretouse.

TheSukhoiT-4wasaSoviethighspeedreconnaissance,anti-shipandstrategicbomberaircraftdesignedundertheleadershipofPavelSukhoithatdidnotproceedbeyondtheprototypestage.Despitedesignsimilarities,theSukhoiT-4wasnotintendedasaSovietequivalentoftheNorthAmericanB-70Valkyrie,butwasintendedtotakeadvantageofmanyoftheXB-70’saeronautical innovations to develop a smaller reconnaissance and anti-carrier aircraft capable of reaching Mach 3. In a Soviet competition todevelop such a bomber, it lost to the Myasishchev, and ultimately theTupolevdesignwhichnowexistsastheTupolevTu-160‘Blackjack’.

TheSukhoiT-4.-aphotographthathasalmostcertainlybeenretouched.(SimonPetersCollection)

AswiththeB-70,theT-4wasmadelargelyfromtitaniumandstainlesssteel, and featured a fly-by-wire control system but also employed a

mechanical system as a backup. The aircraft’s nose lowered to providevisibility during takeoff and landing. A periscope was used for forwardviewingwhenthenosewasraised,andcouldbeemployedatspeedsofupto 600 km/h (373 mph). Braking parachutes were used in addition toconventionalwheelbrakes.

ThefirstT-4,designated‘101’,firstflewon22August1972.ThetestpilotwasVladimirIlyushin,sonoffamedaircraftdesigner,SergeiIlyushin,whosomewhatironically,neverseemstohaveservedinhisfather’sbureau,andnavigatorNikolaiAlfyorov.

Checking the accuracy of records in the former Soviet Union is noteasy,butitappearsthattheT-4onlyflewtentimesforatotal10hoursand20 minutes. It is believed to have reached at least Mach 1.3 using fourKolesov RD36-41 engines. These engines each produced 16,000 kgf(35,300 lb) thrustwith afterburners.The aircraftwasdesigned to achievespeedsofuptoMach3.0,buttheprogrammewascancelledbeforethefullperformanceoftheaircraftcouldbereached.

ComparativeplanviewartworksoftheSukhoiT-4andXB-70A,demonstratingtheirrelativesizes.

TheSukhoiT-4onthegroundandintheair.OneexamplesurvivesinRussia.(SimonPetersCollection).

Another reason of cancelling the project due to theVVS (Soviet AirForce) issuing the requirement of 250T-4s.Meanwhile, some other highrank officers argued into gaining other more practical and supportivefightersinsteadofhavingsuchahugeflyingtitaniumplateintheair.WhenMarshalAndreiGrechkowasmade theMinisterofDefence,heseemshewastoldbyastaffmember,‘YoucouldhaveyourenormousMiG-23orderonlyiftheT-4wouldbeabandoned’.

OneT-4survives today.Aircraft ‘101’ isondisplayat theCentralAirForce Museum in Monino near Moscow. The serial numbers of theprototypes were ‘101’ to ‘106’. Only ‘101’ and ‘102’ were built, otheradditional prototypes ‘103’ and ‘104’ were under construction, ‘105’ and‘106’ only existed on draft charts. Only the ‘101’ completed all the testflights and flew the last test flight before the project was canceled onJanuary22,1974.Therestofprototypeswerescrapped.

TheXB-70AandtheUSSST

In the late 1950s, theUnitedKingdom, France,United States and SovietUnionwereconsideringdevelopingsupersonictransport(SST).TheBritishBristol Aeroplane Company and the French Sud Aviation were bothworkingondesigns,calledtheType223andSuper-Caravelle,respectively.Both were largely funded by their respective governments. The Britishdesignwas fora thin-wingeddelta shape -whichowedmuch toworkbyDietrich Küchemann - for a transatlantic-ranged aircraft for about 100people,whiletheFrenchwereintendingtobuildamedium-rangeaircraft.

Thedesignswerebothreadytostartprototypeconstructionintheearly1960s, but the cost was so great that the British government made it arequirementthatBAClookforinternationalco-operation.Approachesweremade toanumberofcountries,butonlyFranceshowedreal interest.Thedevelopmentprojectwasnegotiatedasan international treatybetween thetwocountriesratherthanacommercialagreementbetweencompaniesandincludedaclause,originallyaskedforbytheUK,imposingheavypenaltiesforcancellation.Adraft treatywas signedon28November1962and thetwocompanies announced that adesigncalled ‘Concorde’wouldbebuiltbyaconsortium.Bythistime,bothcompanieshadbeenmergedintonewones; thus, the Concorde project was between the British AircraftCorporationandAérospatiale.Theconsortiumsecuredordersforover100machines from the major airlines of the day: Pan Am, BOAC and AirFrancewerethelaunchcustomers,withsixConcordeseach.Otherairlinesin the order book included Panair do Brasil, Continental Airlines, JapanAirlines, Lufthansa, American Airlines, United Airlines, Air India, AirCanada, Braniff, Singapore Airlines, Iran Air, Olympic Airways, Qantas,CAAC,MiddleEastAirlinesandTWA.

IntheUSA,Boeinghadworkedonanumberofsmall-scaleSSTstudiessince1952.In1958,itestablishedapermanentresearchcommittee,whichgrewtoa$1millioneffortby1960.Thecommitteeproposedavarietyofalternativedesigns,allundertheirModel733name.Mostfeaturedalargedelta wing, but in 1959 another design was offered as an offshoot of

Boeing’s efforts in the swing-wing TFX project. In 1960, an internal‘competition’ was run on a baseline 150-seat aircraft for trans-Atlanticroutes,andtheswing-wingversionwon.

Artist’srenditionsarealwaysthrilling-thisdesignfromNorthAmerican’sartdepartmentclearlyhasstronginspirationsfromtheB-70.(NAA)

The1961studyreportOn7July1961NorthAmericanreleasedtheresultsofastudyintopossibledevelopmentplansforanearlyAmericanSST.Theinternally-fundedstudyhadbeenconducted toaid theFederalAviationAgency(FAA- itbecamean Administration later) in establishing the development plan for aneventualSST.Thestudyassumedthattheprimarygoalwouldbetodevelopa supersonic aircraft suitable for general airline passenger service andeconomicallycompetitivewithexistingtransportaircraft.

TheNorthAmericanstudyconcentratedonthebestwaytodeveloptheinfrastructurenecessary to supportanSST,notnecessarilyonadefinitivedesignforaproductionaircraft.ThecompanyrealizedthatthedevelopmentofanSSTinvolvedabroadspectrumoftechnical,economic,andpracticalproblems.Many of these problems could be solved by incorporating theproper qualities and characteristics into the aircraft, but others requiredoperationalsolutions-suchasresearchintosonicbooms,airtrafficcontrol,airports and terminal facilities, and operating policies, procedures, andregulations.

NorthAmericanfelt that thenational investment inacommercialSSThadalreadyprogressedconsiderably.Theycited,asexamples,theresearchnecessary to produce supersonic fighters, and the development of the

Convair B-58 Hustler medium bomber, which was the first long-rangesupersonic aircraft developed in the United States. The B-58’s fuelconsumption at supersonic speeds was considerably better than previousaircraft, but the basic design was ‘...essentially a compromise betweenefficientsubsonicandsupersonicperformance’.Anaircraftdesignedforanall-supersonic mission could do better. This was the same conclusionreachedduringtheearlyWS-110Asplit-missionstudies.

The concept of achieving efficient supersonic cruise by eliminatingcompromises for subsonic performancewas first applied to the design oftheXB-70A.Supersoniccruiseefficiencywas improvedto theextent thatthe range of the aircraft at Mach 3 speeds was comparable to subsonicaircraft of similar gross weights. North American believed that the B-70wouldprovideabasisforausefulresearchaircraft,whileadmittingthatitwasalessthanidealconfigurationforanyeventualproductionSST.Afterall,itwastheonlysustainedMach3-capableaircraftinthefreeworld.

They were quick to point out that the United States government hadalready invested over $500 million in technology to support the B-70programme;anamountthatcouldbequicklyleveragedtodevelopanSSTtechnologydemonstrator.

NorthAmericanwantedacautiousapproach,recognizingthatitwouldnotresult inanoperationalaircraft in theimmediatefuture.‘Thispositionpresupposesthattheprimaryobjectiveisaprofitablecommercialtransport,and that a plan is desired which balances urgency, risk, and cost to theextentthatundueriskandexcessivedevelopmentcostsareavoided.Ifanynationalobjectives,suchasprestigeormilitarydesirability,shouldshiftthebalancesothaturgencybecamethedominantconsideration,withcostandriskbeingminorfactors,thenobviouslyitwouldbepossibletodevelopanSSTsomewhatearlierthantheplanspresentedinthisreport.”

Thereportwenton todescribe threepossibleapproachesofachievingthe primary objective of a safe, profitable, supersonic transport forcommercial airline service. The approaches were called: (1) productionprototype, (2) experimental prototype, and (3) military or civil cargoprototype. Also described were two B-70 operational test vehicleprogrammesthatcouldbeimplemented.

North American proposed to build two additional XB-70A airframes,modifiedforuseasSSTdevelopmentaircraft.Thesemachinescouldhaveflown,accordingtoNorthAmericanestimates, fouryearsearlier thanany

purpose-designedSSTprototype,allowingagreatdealoftimetoevaluateareasofinteresttotheSSTdesignerswithmodificationanddesignchanges‘fedback’tothepurpose-builtSSTdesigns.

OneofthemodifiedXB-70swouldbeusedtoprovideaflyingtestbedfornewSSTengines.AlthoughtheGeneralElectricJ93turbojetusedintheB-70 was one of the keys to its great performance, it would not besufficientlyreliableoreconomicalforcommercialservice.Becauseofthis,the government had begun financing the advanced Lightweight GasGeneratorprogrammeandhadawardedcontracts tobothGeneralElectricandPratt&Whitney.Thesupersonicgasgeneratorbeingdevelopedcouldbe adapted to several different engine cycles - turbofan, fan with ductburning,turboramjet,etc.

NorthAmericanbelieveditwasessentialtogainflightexperiencewiththenewenginebeforethefirstprototypeSSTwascompleted-anexcellentidea given the problems encountered with the JTD9 turbofan on thesubsonic 747 a few years later. To accomplish this, they proposedmodifying one of the additionalXB-70A airframes to carry a single SSTengineinplaceoftwooftheregularJ93s.ThiswouldleavethreeJ93sononesideandtheoutboardJ93ontheotherside,allowingtheaircrafttoflyunder any conditions without the use of the SST engine. ModificationswouldbeneededtotheinternalductingtoaccommodatetheincreasedmassflowrequiredbythenewSSTengine;minormodificationstotheexternalmouldlinewouldalsobenecessarytoaccommodatetheincreaseddiameterexpectedofthenewengine.

AnAmericanSST-NorthAmericanstyle!

Theplanandsideviewsrevealafour-manflightcrew,seatingfor170passengers,3restrooms,a

smallgalleybutverylittlespaceforluggageorfuel!(NAA)

Alternatively,oneoftheSSTenginescouldbemountedunderneaththefuselage.Thiswasessentialifthefinaldesignrequiredexternallymountingtheengines-muchliketheeventualBoeingSSTdesign.Inthiscase,flighttestingtheinletconfigurationsandnacelleshapeswouldbenecessary.Theenginewouldbemountedonapylonthatcouldbepartiallyretractedintowhat had been designed as the weapons bay to minimize clearanceproblemsduringtakeoffandlanding.Theenginewouldbeequippedwithaparticularinletdesigntoevaluateengineperformanceataparticulardesignpointspeed.Alternateinletdesignscouldbetested,butnotduringasingleflight.

ThesecondXB-70Aairframewouldbemodifiedtoalimitedpassengerconfigurationbyremovingthemilitaryelectronicsandfuelfromtheupperfuselageandreplacingitwithasmallpassengercompartment.Thisversionhadagrosstakeoffweightof337,000poundsandarangeof2,900miles.Withthesecondversion47,400poundsoffuelwasmovedintotheweaponsbay (for a total of 185,000 pounds) and resulted in an aircraft weighing384,500poundswitharangeofjustover4,000miles.

Asomewhatstrangegraphic,butconsideringthiswasthe1960snotsurprisingisthisB-70artworkthatplacesthebusinessmanracingtohisnextdealintheSSTversion.Thechemist’sbeakersuggeststhatthisartworkwasdonewhilstthoughtsofchemicallyaugmentedpowerplantswerestillbeing

considered-orourbusinessmanwasabouttohaveaverylargeMartini!(NAA)

InMarch1960LockheedwerepromotingtheirMach3-Mach3.5airlinerdesignthatwouldweigharound250,000lbandcostsome$160milliontodevelop.(TheAeroplaneandAstronautics)

Withoutchangingthelineoftheupperfuselage,atotalof36passengerscould be accommodated in four-abreast seating. The internal diameter ofthefuselagewasonly100inches-fourfeetnarrowerthantheBoeing707.A single restroomwould be located at the extreme rear of the passenger

compartment.Agalleywasnotincluded,partlybecauseofalackofroom,and partly because all flights were expected to be so short there was noneed for one.Passenger entry and exit, aswell as emergency evacuation,would be complicated by the height of the XB-70A fuselage above theground.

Twootherconfigurationswerealsoproposedthatslightlychangedtheouter mould line, but provided more realistic passenger counts. Bothincluded the weapons bay fuel. The first extended the internal passengercompartment by 240 inches, resulting in seating for 48 passengers. Thisversionhadagrosstakeoffweightof427,000poundsandcouldfly3,850mileswhilecruisingatMach3.Theotherversionincreasedthepassengercompartmentanother264 inches(fora totalstretchof504 inches) toseat76passengers.Thegross takeoffweight increased to461,000pounds,butrange was reduced to only 3,600 miles at Mach 3. Neither modificationchanged the overall length of the fuselage, but resulted in a morepronouncedchangeinlineoftherearpartoftheneck.Theexpectedeffectonstabilitywasconsiderednegligible.

NorthAmerican’s rationale forusinganXB-70AasanprecursorSSTdemonstratorwascompletelyvalid.Theprimarycontributionwastheearlydefinition of problems associated with the operation of an SST, madepossiblebylimitedpassengerflightsasearlyas1965.SincetheFAAwouldnothavecertificatedtheaircraft, theywouldhavebeenlimitedtomilitaryor government operations, but that did not create great problems Theexpected areas of concern included air traffic control, airport operations,maintenance,schedulingandpossiblenoisecomplaintsfromsonicbooms.Sufficientlead-timewasavailabletoresolvetheseproblemsinanefficientand orderly manner before large numbers of SSTs were produced.Regulations and systems could be developed to monitor and control theoperations of supersonic aircraft by the time production aircraft wereintroduced into airline service. The FAA could use the early serviceexperiencetowritenewFederalAirRegulationscoveringthecertificationprocessanddesigncriteriaforsupersonictransports.

Bymid-1962,itwasbecomingclearthatthetentativetalksearlierthatyear between theUnitedKingdom and France on amerger of their SSTprojectsweremore serious thanwere first believed - and thereforemuchmore of a threat to the American aviation industry - than was originallythought. This set off something of a wave of panic, as it was widely

believedthatalmostallfuturecommercialaircraftwouldbesupersonic,anditlookedliketheEuropeanswouldstartoffwithahugelead.

ClearlythisartworkistodemonstratethetransitionfromB-70toSST.However,therearealsothefirstinklingofafurtherNAARockwellproduct,theB-1withtheenginenacelles.(NAA)

TheConcordecameasnosurprisetoAmericanSSTenthusiastsintheFederalAviationAgency(FAA),whichhadbeensponsoringSSTresearchand feasibility studies since 1960. Ever since FAA administrator NajeebHalabyhad assumedoffice in early 1961he immediatelybegan lobbyingfor an American SST development project. He also rejected numerousEuropean, especially British, overtures for a joint SST programme andneverhadanyintentionofbecomingpartnerswiththeBritishortheFrench.AshetestifiedonCapitalHillinApril1961,‘Wewanttobethereaheadofour competitors’. This American posture helped drive the British andFrenchintoeachother’sarms.

The creation of the Concorde programme provided Halaby with aformidablepromotionalweapon.ByNovember1962 thedangerposedbythe Anglo-French project was his main lobbying theme. In a report toPresidentKennedy,HalabyportrayedasuccessfulConcordeasforcingtheUnitedStates to ‘...relinquishworldcivil transport leadership’ thatwouldcost over 50,000US jobs and potentially leading toU.S. dependence onforeign suppliers for supersonic military aircraft. Halaby clinched hisappeal by jingoistically warning that conceivably an American presidentwouldsomedaybeforcedtoflyinaforeignaircraft.

TheConcordeannouncementwasacrucialfactorinmobilizingsupportwithin the administration for an American SST program. As Halabyrecalled years later, ‘When deGaulle embraced the joint [Anglo-French]Concorde project, it seemed to trigger competitiveness in JFK. In fact, IthinkJFKassociatedtheConcordemostwithdeGaulle;onmorethanone

occasion,hesaid,‘We’llbeatthatbastarddeGaulle.’EverytimeIsawthePresident,fromthedaydeGaullemadehisannouncement,hewouldpressmeonhowourstudiesweregoing—????andhow theBritishandFrenchweredoing’.

ClearlytheB-70couldbeusedasaseriousresearchtoolandprovidedafoundationalreadyinplacethattheAmericanscoulduse-andthatstartingpointwasMach3speeds.GoingthroughalltheUSmaterial,oneformsthedistinctimpressionthattheAmericanswerebeing‘driven’bytheConcorde-tobetteritinbothspeedandsizeandthereforewinthecommercialbattle.TheyweredeterminedthatwhathadhappenedadecadeorsoearlierwhenthedeHavillandComethadgivenalltheAmericanmanufacturersabloodynosebysoundlybeatingthemtothecommercialjetmarketwasnotgoingtooccuragain.

InNovember 1962 theNASAResearchCenter initiated a programmecalledSCAT-SupersonicCommercialAirTransport-inordertoevolveaconfiguration that could cater for unique requirements for a commercialSSTovertheentirespectrumfromtake-offtolanding.Theirstudiescamedown to two approaches - SCAT-4, a was a fixed-wing proposal thatintegratedwing, fuselage, engines and tail into a highly swept, camberedandtwistedaircraftdesignaimedatminimisingwavedragduetolift,andthe variable-sweep SCAT-15. By early 1963, two other geometries werealsobeingpursued:theSCAT-16variable-sweepproposalthathadevolvedfrom-15,andSCAT-17,a fixeddelta-wing layoutwitha forwardcanardsurface-inotherwords,amodifiedB-70design.

InanevenmoredirectwaytheConcordewasamajorfactorforcingthePresidenttoannounceanAmericanSSTprogramme.Duringthespringof1963 PanAmericanAirlines - the ‘flagship’ of American airlines, flyingmany international routes, including thecrucial transatlantic run,andwhotraditionallyledthewayinorderingnewaircraft-madesurethattheFAAand the White House knew that the airline was considering ordering anumberofConcordes,althoughitreallywantedtopurchaseafleetoflargerandfasterAmericanMach3SSTs.JuanTrippe,presidentofPanAmerican,informed high-level US officials, including Halaby, Civil AeronauticsBoard Chairman Alan Boyd, and Secretary of the Treasury C DouglasDillion,andthatheintendedtoplacea‘protectiveorder’forsixConcordes.

Trippe’s actions had the desired effect. Vice-President Lyndon BJohnson,whowas chairing a cabinet-level SST review committee at that

time and who had already recommended an SST go-ahead to PresidentKennedy,becameextremelyworriedovertheimpactofthePanAmericanConcorde decision. Armed with Johnson’s recommendation and theknowledgeofTrippe’smovetoorderConcordes,Kennedyquicklydecidedto establish anSSTprogram.But toKennedy’s great anger andHalaby’sshock. Pan American announced its order for six Concordes on 4 June1963,onedaybeforeKennedy’sSSTdeclaration.

ThebigwhitebirdtaxisatEdwardsAFBsometimeduringservicewithNASA(USAF)

‘Cecilthesea-sickseaserphent’banksawayfromthecameraduringoneofthesonicboomtests.(USAF)

On5June1963, inaspeechbefore thegraduatingclassof theUnitedStates Air Force Academy, President John F. Kennedy committed theUnitedStates to ‘develop at the earliest practical date the prototype of acommerciallysuccessfulsupersonictransportsuperiortothatbeingbuiltin

anyothercountryintheworld....’In the summer of 1963Halabywas at the peakof his power.Hehad

achieved his long-sought goal: an SST programme under FAA direction.However,he soonsufferedadramaticdecline inauthority fromwhichhewouldneverrecover.Hisfallfromgracewaspartiallyduetothechangeinadministrations that occurred as a result of the assassination of John FKennedyonNovember22,1963.Halaby,aKennedyappointee,wasneverclose to Lyndon Johnson and did not particularly get along with him.AlthoughaSST supporter, Johnsonalsowanted toputhisown stamponwhathadbeenaKennedyprogramme.

Justasimportantinpromotingapowershiftwerecomplaintsfromthemanufacturers-theyobjectedtoPresidentKennedy’soriginalcost-sharingrequirements. InAugust1963KennedyaskedEugeneBlack, formerheadof theWorldBank, toreviewtheSSTfinancing issue.Blackbrought inafellow industrialistand financier,StanleydeJ.Osborne - their reportwassubmittedtoPresidentJohnsoninDecember1963andquickenedHalaby’sdecline.BlackandOsbornesidedwithindustryindecidingthat the75-25cost-sharing ratio was too much and recommended that 90% of thedevelopment cost be assumed by the government and 10% by themanufacturers. Black andOsbornewent beyond their charter and offeredproposals that were the opposite of what Halaby advocated. TheyrecommendedthattheSSTprogrammebetakenfromtheFAAandbemadean independent ‘Authority’, reflecting a growing opinion by informedpersonsinthegovernmentandindustrythattheFAAlackedthemanagerialskillsandexperiencetorunacomplexeffortliketheSSTprogramme.Theyalso saw no necessity for a crash programme, noting that theBritish andFrenchwerealreadyencounteringmajorproblemsoftheirown.

TheBlack-Osborne report triggered a series of internal administrationreviews of the whole SST effort in early 1964 that finally led to theformationofthePresident’sAdvisoryCommitteeonSupersonicTransport(PAC-SST)inApril1964.Thiswaschairedbyprobablythemostpowerfulandinfluentialofficialinthegovernmentatthattime,nexttothepresident,Secretary ofDefenseRobert SMcNamara, andwasmade up of cabinet-level officials, including the secretaries of treasury and commerce, theBoomdirector, the administrators ofNASAand theFAA, andBlack andOsborne.Amassivepowershifthadtakenplace.McNamarawasnowthemost important decision maker in the SST programme and major policy

decisionswerenowmadeinthePAC-SSTratherthantheFAA.Bydefinition,aChairmanisselectedtopresideovermeetings,andlead

acommitteetoconsensusfromthedisparatepointsofviewofitsmembers.Thechairmanisexpectedtobeimpartial,fair,agoodlistener,andagoodcommunicator. Nothing could be further from the truth with RobertMcNamara.He,andhisteamofWhizzKidshadkilledofftheB-70-nowhesetaboutkillingofftheAmericanSST.Inhisownwords:

‘RightatthebeginningIthoughttheprojectwasnotjustified,becauseyou couldn’t fly a large enough payload over a long enough nonstopdistance at a low enough cost to make it pay. I’m not an aeronauticalengineer or a technical expert or an airline specialist or an aircraftmanufacturerbutIknewthatIcouldmakethecalculationonthebackofanenvelope.

SoIapproachedtheSSTwiththatbias.PresidentJohnsonwasinfavorofit.AschairmanofthecommitteeIwasveryskepticalfromthebeginning.Thequestion, inasense,washowtokill it. Iconceivedanapproach thatsaid:maybeyou’reright,maybethereisacommercialmarket,maybewhatweshoulddoistotakeitwithgovernmentfundsuptothepointwherethemanufacturersandtheairlinescandeterminetheeconomicviabilityoftheaircraft.We’lldrawupaprogramonthatbasis’.

TestingthebangsTheneedtoevaluatetheeffectsonsonicboomsonthegeneralpopulationled to the running of a series of sonic booms being ‘dropped’ overOklahomaCity,Oklahomaoveraperiodofsixmonthsin1964.

The experiment, which ran from 3 February through 29 July 1964inclusive,intendedtoquantifytheeffectsoftranscontinentalSSTsonacity.TheprogrammewasmanagedbytheFAA,whichenlistedtheaidofNASAand the USAF. Public opinion measurement was subcontracted to theNationalOpinionResearchCenter(NORC)oftheUniversityofChicago.

Itwasnotthefirstexperimentofthisnature,astestshadbeendoneatWallops Island, Virginia in 1958 and 1960, at Nellis Air Force Base,Nevada in 1960 and 1961, and in St. Louis,Missouri in 1961 and 1962.However,noneof these testsexaminedsociologicalandeconomic factorsinanydetail.TheOklahomaCityexperimentsweremuchlargerinscope,seekingtomeasuretheboom’seffectonstructuresandpublicattitude,andtodevelopstandardsforboompredictionandinsurancedata.

OklahomaCitywaschosen,astheregion’spopulationwasperceivedtobe relatively tolerant for such an experiment. The city had an economicdependencyonthenearbyFAA’sMikeMonroneyAeronauticalCenterandTinkerAirForceBase.

Atrulystunningpictureof20001seenupcloseandpersonalfromoneofthechaseaircraft.Thewingtipsareinthefullydownposition.(USAF)

Startingon3February1964,thefirstsonicboomsbegan,eightboomsper day that began at 07:00 and ended in the afternoon. The noise waslimitedto1.0to1.5pound-forcepersquarefootforthefirsttwelveweeks,thenincreasedto1.5to2.0psfforthefinalfourteenweeks.Thisrangewasabout equal to that expected from an SST. Though eight booms per daywereharsh, thepeakoverpressuresof2.0psfwereanorderofmagnitudelower than that needed to shatter glass, and were considered marginallyirritatingaccordingtopublishedstandards.

Oklahomans initially took the tests in their stride, as the boomswerepredictable and coming at specific times. An FAA-hired camera crew,filmingagroupofconstructionworkers,weresurprisedtofindthatoneoftheboomssignalledtheirlunchbreak.

However, in the first fourteen weeks, 147 windows in the city’s twotallestbuildings, theFirstNationalBankandLibertyNationalBank,werebroken.By latespring,organizedcivicgroupswerespringing intoaction,butwere rebuffedbycitypoliticians,whoasked them to show legislatorstheirsupport.AnattempttolodgeaninjunctionagainstthetestswasdeniedbydistrictcourtJudgeStephenChandler,whosaidthattheplaintiffscouldnot establish that they suffered anymental or physical harm and that thetestswereavitalnationalneed.Arestrainingorderwasthensought,whichbroughtapause to the testsonMay13until itwasdecided that thecourt

hadexceededitsauthority.Pressure mounted from within. The Federal Bureau of the Budget

lambastedtheFAAaboutpoorexperimentdesign,whilecomplaintsfloodedintoOklahoma SenatorA SMikeMonroney’s office. Finally, East Coastnewspapersbegantopickuptheissue,turningonthenationalspotlight.On6 June the Saturday Review published an article titled The Era ofSupersonicMorality, which criticized themanner in which the FAA hadtargeted a city without consulting local government. By July, theWashington Post reported on the turmoil at local and state level inOklahoma. Oklahoma City council members were finally beginning torespondtocitizencomplaintsandtoputpressureonWashington.

This pressure put a premature end to the tests. The results of theexperiment,reportedbyNORC,werereleasedbeginninginFebruary,1965.The FAAwas displeased by the overly academic style of the report, butstressedthepositivefindings,saying‘...theoverwhelmingmajorityfelttheycould learn to live with the numbers and kinds of booms experienced’.Indeed,theNORCreportedthat73%ofsubjectsinthestudysaidthattheycouldliveindefinitelywitheightsonicboomsperday,while25%saidthatthey could not. About 3% of the population telephoned, sued, or wroteprotest letters, but Oklahoma City surgeons and hospitals filed nocomplaints.

However, with the city population at 500,000, that 3% figurerepresented15,000upsetindividuals.Atleast15,452complaintsand4,901claimswerelodgedagainsttheUSgovernment,mostforcrackedglassandplaster.TheFAArejected94%ofalltheclaimsitreceived,fuelingarisingtideofangerthatsoaredevenaftertheexperiment’sconclusion.

TheOklahomaCity experimentswere partly to blame for weakeningtheFAA’sauthorityinsonicboomissues.Afterthetests,PresidentLyndonB.Johnson’spresidentialadvisorycommitteetransferredmattersofpolicyfromtheFAAtotheNationalAcademyofScience.SecretaryoftheInteriorStewartUdallcomplainedthattheNASdidnotincludeoneenvironmentalpreservationist,andpointedoutthatalthoughtheOklahomaCitytestswerestackedinfavorof theSST, theywerestillextremelynegative. Indeedby1966,nationalgrassrootscampaignsagainstsonicboomswerebeginningtoaffectpublicpolicy.

TheFAA’spoorhandlingofclaimsanditspayoutofonly$123,000ledtoaclassactionlawsuitagainsttheU.S.government.

SSTdesignanddevlopmentworkNorth American submitted the NAC-60 design, which was essentially ascaled-upB-70withalesstaperedfuselageandnewcompound-deltawing.The design retained the high-mounted canard and box-like engine areaunder the fuselage. The Lockheed CL-823 was essentially a scaled-upConcordewithacompound-deltawing(asopposedtothesmoothedogeeoftheConcorde),withindividuallypoddedengines.

TheAmericandesigns,theBoeing2707andtheLockheedL-2000weretohavebeenlarger,withseatingforupto300people.Runningafewyearsbehind Concorde, the winning Boeing 2707 was later redesigned to acroppeddeltalayout.

It was obvious that supersonic flight had to provide a shirtsleeveenvironment for passengers - it would be totally impracticable to fithundreds of people with temperature-resistant pressure suits beforelaunching them across the sky at speeds in excess of Mach 2. Lots ofdesignershad lotsof theoriesas tohow thiswouldbepossible,but somerealisedthattheXB-70Aprogrammewasattemptingtosupplysomehard,real-time solutions. It was almost if the aircraft had been readymade toanswer some of the questions. As always, the XB-70A programme washaving financial problems because of arguments between Congress andMcNamara’sDoD.NASAwashappytoclimbaboardandfundthetestingwiththeideathatitmightbeagoodwaytobolstertheSSTprogramme,forthereweremanyproblemstobesolvedbeforeanAmericanSSTcouldbebuilt.

In 1965, the United States had not yet come up with accurate windtunnel models, so it had difficulty estimating the base drag of a multi-engineaircraft.TheXB-70Awasabletorunthesetestslive,duringregularflight. Tests called for cameras to be placed on the fuselage so in-flightphotographs could be taken to resolve boundary layer transition patternissues.Lateron, awingglovewouldbe installed,permitting the studyofthe effects of roughness on airflow, especially during the subsonic-transonic-supersonictransition.

Achartshowinghowaseriesoffourmicrophoneswerearrayedforthesonicboomtests.(AFMCHO)

Theinstrumentationwasdesigned,manufactured,andinstalled-mainlyonAirVehicleTwo-withdatagathering,reduction,andanalysisperformedonanon-interferencebasisduring theXB-70Adevelopmentprogram.AsNorthAmericanAviationstatedinitsfinalreport:‘TheSSTflightresearchdatawasobtainedinvariousareasasdesignatedbytheeighttasks.Allofthe tasks indicated were sponsored by NASA except for acoustic loadswhichwassponsoredbyFAA’.

Prior to the loss ofAV2, the aircraft had become a surrogate for theproposedBoeingSST.The government and private researchers embarkedonamajorsonicboomtestprogrammeatEdwardsinanefforttoaccuratelyforecast psychological reaction and structural damage associated withoverpressures from supersonic transports. The National Sonic Boomprogramme (NSBP)was set up by the President’s Office of Science andTechnology, and consisted of three principal participants - theAir Force,NASA,andStanfordResearchInstitute.

The XB-70A was used to perform the tests because it most closelyresembledthesizeoftheproposedBoeingSST.TheValkyriewastheonlyaircraft capable of simulating the SST primarily becauseweight and sizehadamarkedaffectonsonicboomsignatures.AlthoughoverpressuresofequalpeakmagnitudescouldhavebeenobtainedbyusingF-104sandB-58s,thedurationoftheboomitselfvariedwitheachaircraftastotheshapeoftheshockwavesthemselvesandtheforcesinvolved.

TheNSBPbeganon6June1966whenAV2performedtheinitialsonic

boomtest, reachingMach3.05at72,000feet.ThesecondNSBPtestwasconducted twodays laterbut itwasfollowedby themid-aircollision thatdestroyedtheaircraft.

BoththeAirForceandNASAwereunsurethatAV1,withitsMach2.5speed limitation, could continue the research since the Boeing SST wasplannedasaMach2.7aircraft.AV1hadnotflownsince9MaybecausetheoriginaltestprogrammewasscheduledtoendinearlyJune.Nevertheless,given that AV 1 was the only large supersonic aircraft available, NASAthought that it had no choice other than to install a duplicate set of testequipment in AV 1. During this period AV 1 was also equipped withimprovedescapecapsulesandanautomatedAICS,therebyeliminatingitstroublesomemanualairinductioncontrolsystem.

SubsequenttotheXB-70Aflighttestdevelopmentprogram,twoflightresearch programmes were initiated on the remaining XB-70A. The firstprogrammewasforSonicBoomMeasurementsandwassponsoredjointlybyNASAandUSAF.

Thefirstoftheseflightsoccurredon11March1966andtheprogrammewascompletedon1January1967.Theprimarypurposewastodeterminethepropermethodofcombiningthetheoreticalsonicboomintensityduetoliftandduetovolumeforthefarfieldcase.Pressuresignaturesofseveralaircraft, but principally the XB-70A, were measured on the ground atvarious distances from the ground track of the air vehicle. Atmosphericeffectsonthesonicboomintensitywerealsoinvestigated.

TheXB-70Awasfittedwithtwosetsof‘passengerwindows’whilewithNASA,inordertovisuallydemonstratetheAmericanSST.Theywere,inreality,juststickers.(USAF)

TheILAFsystemofexcitervanesandassociatedsensorsinstalledbyNASAonboardAV1forthe73rdandsubsequentflights.NASAhopedthissystemwouldserveasaprototypeforadvancedsystemsthatwouldbeinstalledonSSTs,enablingthemtoflywithincreasedsmoothnessand

reducedthefatigueonbothpassengersandairframe.ThefirstILAFflightwason11June1968;fromthenuntiltheendoftheprogrammein1969AV1acquiredmuchinformationapplicabletonot

onlythedesignoffutureSSTsbutalsolarge,supersonicmilitaryaircraft.(NASA)

A follow-on programme was sponsored by NASA and was aninvestigationintothecontrolofstructuraldynamics.Thefirstflightwason25April1967andtheprogrammewascompletedon4February1969whenthe #1 XB-70A was ferried to Wright-Patterson AFB for the USAFMuseum.

To conduct the structure dynamics investigation, the air vehicle wasmodifiedfortheinstallationofanExciterVaneSysteminthenosesectionand an elevon control system titled Identically LocatedAcceleration andForce(ILAF).

TheExciterVaneSystemcomprisedoftwosmallvanesprotrudingfrom

both sides of the nose section, tied together through the fuselage andhydraulicallydriven.Thesystemwascontrollablefromthecockpitforbothfrequency and amplitude which provided controlled dynamics to the airvehicle structure. The ILAF system tied into the XB-70A FlightAugmentationControlSystemwhichprovidedelevoncontrolforstructuraldynamic dampening. This concept was based on locating the inputaccelerometers near the elevons (for system stability), mixing this inputsignal with CG signals which cancelled normal flight accelerations andprovidedastructuraldynamicsfrequencyspectrum.

Meanwhile, behind the scenes, the initial concern caused by theConcorde had faded by 1964 and the Concorde programme was not thecenterofAmericanSSTpolicy-makingattention.Asinthepastalmostallsignificant American-European SST exchanges were limited to purelytechnical SST information. In fact, the Concorde seemed to be in deeppolitical and technical trouble. In late 1964 the newly elected Labourgovernment called for a thorough review of British participation in theprogramme. The CIA reported in October that the Labour Party’s stancewould have serious repercussions for the Concorde, andMcNamara waseven warned in November 1964 that Great Britain might withdrawcompletely. However, McNamara’s key SST aide, Joseph Califano,believedthattheBritishwouldprobablycontinuetoparticipate,thoughtheBritish reappraisal had clearly weakened the Concorde. ‘Whatever theoutcome...’CalifanotoldMcNamara,‘...theintroductionofsomuchstrainanduncertaintyintotheConcordeprogrambecauseofthepoliticalfactorsmakesitdoubtfulwhetherthedegreeofcooperationthathasthusprevailedbetweentheBritishandFrenchcanbemaintained’.

FromNorthAmerican’sownfilescomethislistofadditionalequipmentinstalledintheXB-70Aforsupersonictransporttests.

InterestinglythereareveryfewreferencesintheentireB-70StudyReporttotheairframe‘growing’duetothermalexpansioncausedbyfrictionalheating.(NAA)

DesignrevisionshadalsosettheConcordeprogrammebackasmuchastwoyearsanddevelopmentcostswerespiraling(estimatedat$400millionfortheBritishshareinNovember1964).ANASAanalysisoftheConcordeoptimisticallyestimatedthatConcordedirectoperatingcostswouldbe1.4centsper seat-mile - comparedwith1.0 to1.1centsper seat-mile for thesubsonicBoeing707.CalifanoalsoindicatedthatConcorde’sperformancewouldprobablyfurtherdeteriorate.

Attheendof1964onlythestrongestSSTproponents,includingHalabyand potential SST contractors like Lockheed, even bothered stressing thedanger of Concorde success. Both SST proponents and sceptics in theUnited States also continued their long-standing aversion to joint SSTdevelopmentwith theEuropeans. In1965 theAmericans squashedanewfeeler by the British and French for co-operation and, according to theFrench,for‘dividingtheworldSSTmarket’betweentheUnitedStatesandtheEuropeans.

The generally disdainful American view of the Concorde effort wasexpressed at the 30 March 1965 PAC meeting when CIA director JohnMcCone, in presenting the current intelligence on theConcorde - paying

carefulattentiontonotingthattheCIAhadnotused‘...clandestinesources’becauseofthe‘...riskofoffendingoneofthehostcountries’andminimizedConcordeaccomplishments-interestingly,heneverbotheredtostatewhichcountry he was not concerned about offending! He reported that littleEuropeanworkseemedtohavebeendoneonthesonicboomproblemandthat extensive design modifications and economic uncertainties wouldsurelycause furtherdelays.This in itself is remarkablysurprising, for theBritishaviationmagazinesalonecontainmanyreportsonnoisestudiesandassociatedworkdonefromasearlyas1959.McConewentontoremindthePACmembers thatasonemovedgraduallyupward fromtheMach-1.5 totheMach-2rangeunexpectedtechnicalproblemswereboundtoarise,andthese would take time to correct. He was not at all worried about theConcorde’s alleged two-to-three-year lead, and suggested at any rate thatAnglo-French forecasts be taken ‘with a grain of salt...quite a large one’.Halaby,ofcourse,disagreed.HenotedthattheConcordehadalreadywonsignificant airline commitment - in addition to BOAC andAir France, atotalofforty-eightdeliverypositionshadbeenreservedbyotherairlines.

AlsofromNorthAmericancomesthisdiagramshowingwherethededicatedinstrumentationwasinstalledintheXB-70Aairframe.(NAA)

McNamara strongly backed McCone, calling his review ‘...a veryinterestingreport,thebestwehavehadsofar.’McNamaraarguedthattheAmericanSSTshouldbeaprofitablecommercialventureandthatthepaceofConcordeworkshouldnotdictateAmericanSSTdevelopment.He feltthat the United States would ultimately build a better SST; there was

thereforenoneedtoworryaboutConcorde’slead.McNamarawasalsoreceivingeconomicevaluationsthatsupportedhis

scepticismabout theConcorde fromanSSTeconomics task force thathehadestablishedinthePentagoninearly1965,headedbyStephenEnke,arespected economist. The estimates of the task force gave the Concordeonly a minor market niche, and Enke was convinced that the ConcordewouldhaveahardtimekeepingupwiththeAmericancompetition.Anglo-French dates for commercialConcorde operationwere termed ‘...patentlyunrealistic’.TheBritishandFrenchwereinexperiencedatsustainingMach2.0 speeds. One task forcemember noted, ‘The American SST has greatgrowthpotential,theConcordealmostnone’.

NorthAmericanproposedanumberofdifferentversionsoftheB-70thatcouldbeusedasaSST.

Thefirstwasthisoperationaltestvehiclethathadthecompartmentaftofthecockpitconvertedintoa100-inchwidefourabreastseatingarea.

Whilenotclearedforcommercialairlineuse,thisB-70couldbeinvolvedinanumberoftasksaheadofacommercialSSTdesign.

BytheirMay5,1965meeting,thePACmembers,includingadefeatedHalaby - who would shortly leave the government to work for PanAmerican - , appeared even less troubled than before by Concorde andmoreconfidentof theAmericanSST’sultimatesuccess.McNamaraflatlypredicted that the American SST would be ‘...far more successfulcommercially than theConcorde’ and that theUnitedStatesneednot feelthepressureofa‘crash’Concordeeffort.

American unease over the European SST refused to go away, andrenewed concern began to grow during the latter half of 1965. Thisdevelopment was due to a genuine worry about Concorde as a threat toAmericanaviation interestsand toa reinvigoratedFAA lobbyingeffort toinfluencePAC-SSTmembers thatwasdirectedby two air forcegenerals,WilliamMcKee,thenewFAAadministrator,andJewellMaxwell,thenewdirectoroftheSSTprogramme.

NorthAmericanalsoproposedanumberofothermodificationsthatwouldallowupto76passengerstobecarriedby‘stretching’thefuselagesomewhat.(bothNAA)

Takenfromoneofthechaseaircraft,62-0001isseeninflightwiththewingtipsinthemid-wayposition.(USAF)

InAugust1965Enke’s task forceproducedan important studywhichconcluded that Concorde would displace approximately 23% of the 100-odd American SSTs expected to be sold by 1985 under a sonic boom-induced restricted route condition. The study concluded that Concorde’slower plane-mile costs —in contrast to the Concorde’s higher seat-mile

costs-wouldmaketheConcordemoresuitableforlow-densityroutesandhours.Cheaper subsonicairfareswouldhurt the largercapacityAmericanSST more than the Concorde, as would route restrictions, given theresultinglimiteddemandforSSTairtravel.BritishandFrenchproductiontechniquestendedtobelesscapital intensivethanAmericanones.Itwentontosay:‘TheUSSSTneedsarelativelylargesupersonicmarket-whichprobablymeansonlymoderatelyrestrictedroutesforConcordecompetitiontobeunimportant’.

The FAA was employing a well-planned and effective lobbyingcampaignthatemphasizedtheConcordethreat.TheagencytoldthePAC-SST in early October 1965 that the gap between time of announcedConcorde commercial introduction (1971-1972) and estimated AmericanSST commercial availability (mid-1975) was sufficient to assure anadequatemarketfortheConcordegivenareasonablyeconomicdesign.

The United States must assume that Concorde will be a successfulprogramme, declared theFAA.Thenotion thatConcordemight be a realfuture competitor assumed new credence at the 9 October PAC-SSTmeeting where Osborne and Boeing - via Secretary of Commerce JohnConnor - reported that the Concorde would actually meet its announcedschedule.MediareportshelpedtheFAA.

Enke immediately attempted to block theFAA resurgence. In January1966Enke flew toParis andLondon tomeetwith high-levelFrench andBritishofficials,ostensiblytodealwithvariouseconomicandsonicboomresearch problems, but really to discuss ‘time phasing’ - proportionatelyslowingdownboththeAnglo-FrenchandAmericanprogrammes.

Enke sent back less than favourable assessments of Concorde:economicprospectswerepessimisticandtheairlineswerenotenthusiasticabout theaircraft.Significantly,Enkereported that theBritishandFrenchhad different performance and political goals; Concorde was a matter ofprideandnationalprestigetotheFrench,whiletheBritishtendedtoviewitasthepricetheyhadtopaytoavoidaFrenchvetoofBritishmembershipintheCommonMarket. ‘Great Britain...’, Enkewrote, ‘...was the reluctantpartner, with the British mood being one of fatalistic hopelessness thatcombined an awareness of financial losses aheadwith a belief that littlecouldbedoneaboutit’.Enkeconcludedthat thetimewasripetoexploretimephasinganddesigndifferentiationwiththeBritishandFrench.Then,totheFAA’sgreatdismay,Enke’sdiscussionsandviewswereleakedtothe

Britishpress.TheFAAquicklycounter-attacked,emphasizingthepositiveaspectsof

Concorde’s development. It received additional favourable Concordereviews from TWA, Lockheed, and Boeing and began to systematicallyorganizeandassessConcordeinformation.

Concorde’s imageagainbegantodeclineintheeyesofkeyAmericandecision makers. The CIA reported in late March 1966 of Concorde’senginedifficulties.Atthe6May1966PAC-SSTmeetingMcNamarastatedthat thisnegative informationdemonstrated that although ‘...not a failure,theConcordedidhavea fewproblems’.Headded that lackofsupersonicexperiencehadledtheBritishandFrenchtounderestimatetheConcorde’stechnical difficulties. BothMcCone andMcNamara oncemore explicitlywarnedagainstlettingConcordeinfluenceAmericanSSTdevelopment.

TheinformationonConcordethattheAmericansreceived-frompublicandprivatesources-wascontradictory.SomeofthedataindicatedthattheConcorde was proceeding smoothly and on schedule, and the FAAparticularlywasmore thanwilling to believeConcorde claims.TheFAAwasassistedinearlyJuly1966byJuanTrippeofPanAmerican,whotoldthePACthattheConcorde’stimetablewasrealisticandthatitsperformancecharacteristicshadimproved.Hepointedlyadded,‘Anyplacethatwe[PanAmerican]don’thavesuchaship[theConcorde]covered,asmoreorlessalossleaderforadvertisingpurposesandsoforth,wethinkwewouldbeintroubleduringtheperiodafterConcordedelivery’.

Afullscalemock-upoftheswing-wingBoeingSST.(AeroplaneandAstronatics).

ConcordeswerebuiltinboththeUnitedKingdomandFranceandenteredcommercialservicein1976-27yearslatertheywereretired.(BAC)

Again the lack of American confidence in the Concorde programmecame to the fore. US sources throughout the rest of 1966 stressed theConcorde’s long-term problems, such as substantial cost increases, andmaking claims regarding the Europeans neglect of the sonic boom issue,andthelikelihoodofasubstantialdelay.

ThiswasbroughtaboutbyaUSdisregardnotonlyoftheConcordebutalso that theAmericansgenerallydisparaged theentireEuropeanaviationindustry. Juan Trippe spoke of the ‘...miserable performance in Europecompared to what we have done in this country’ and admitted that PanAmerican’s Concorde orders were nothing but ‘...a sort of an insuranceprogram’tocoverPanAmericanifanAmericanSSTwasdelayed.

SupportingAmericanpooropinionofEuropeancommercialaviation,anumber of CIA reports emphasized Concorde’smajor technical and non-technical problems, and, though acknowledging that Concorde wascurrently on schedule,warned of serious future delays in theConcorde’sproductionphase.Thesearchforsolutionstotechnicalproblems,accordingto theCIA, could delay the programme for up to two years. In the non-technicalarea, theCIAreportsdwelledonpotentiallyfataldisagreements;theFrench,worriedabouttheproposedAmericanSSTandunsureoftheirBritishpartners,wantedtoenterproductionquickly,andrejectedaBritishproposaltoincreaseConcordepassengercapacityto167;theBritish,ontheotherhand,alreadydoubtingtheConcorde’seconomicstrength,felt thatalargervehiclewasneeded tocompetewith theAmericanson transatlanticroutes, which would require more development time. No one seemed toquestiontheaccuracyofanyofthesereports,which,iftheywerebasedon1966-era data, were seriously inaccurate and out of date. Enke and hisgroup naturally continued to minimise the seriousness of the Concordechallenge,arguingthatevenayear’sslippageintheAmericaneffortwould

havelittleimpactonAmericanSSTsales.At the 9October 1966PAC-SSTmeeting presidential science adviser

DonaldHornigaddedthattheConcordedevelopershad‘...sortofshuttheireyestothesonicboomproblemandresignedthemselvestoatleasthavingtheoverseasmarket’.EvenMaxwellattheFAAadmittedtothePAC-SSTthatnosolutionshadbeenfoundfortheConcorde’sproblems;developmentcostsandthesalespricewereincreasing;butsowereairlineorders.

AstheCIAalsoacknowledgedinOctober1966,theConcordedidexistandwasapparentlyonschedule.Concordeordershadincreasedfromfifty-four toa tentativesixty-foursinceAugust,and theprojecthadassumedahigh order of diplomatic political importance. The CIA observed that‘GeneraldeGaullecontinuestoviewtheConcordeasanimportantstepindemonstratingthetechnicalcompetencerequiredofamajorpower.Heseestheprojectasameans,also,toenhanceFrenchprestige,particularlyvis-a-vistheUSandhastakenapersonalinterestinit.TheFrenchgovernment’sdetermination that the project be completed, despite growing Britishdisenchantment because of mounting costs also stems from Gaullistassertions that France’s ‘independent foreign policy has not harmed itsfriendship with its allies’. As another high French official put it, ‘Fortechnological, commercial, and also political reasons, our Europeancountries cannot allow themselves to sink to the level of meresubcontractors’.

TWApresidentCharlesTillinghastwasevenmorebullish.Hetold thePACon7December1966thattheConcordecouldindeedbearealthreat,althoughtheConcordehadlousyseat-mileeconomicsandthatTWAwouldlove to skip the Concorde, he maintained that if the American SST fellfurtherbehind,TWAwouldhavenochoicebuttooptfortheAnglo-Frenchaircraft. Tillinghast estimated that TWA could afford at the most aneighteen-month lag. Tillinghastwarned the PAC ‘TheBritish andFrenchare in. They may have been silly to have done it. They are in. They aregoingahead.IthinkanyonewhohasatendencytowriteofftheConcordeasalotofflopisbeingveryunrealistic.Itseconomicsareconsiderablylessthansensationalbutitwillfly,itwillflywell.’

Twoofaseriesofpicturestakenduringenginegroundruns.Therawpowerofthesix-packcanclearlybeseen.(USAF)

ThePAC’sfourthandfinalinterimreporttothepresident,emphasizedthetechnicalandeconomicsuperiorityoftheAmericanSST,andobservedthatmanyaircraftdevelopmentproblemstypicallydonotbecomeapparentuntil the prototype stage. The PAC expected significant delays withConcorde, and predicted little performance improvement, given theaircraft’s small engine thrust and resulting limited range. The committeealso claimed that Concorde’s estimated direct and total operating costswere, respectively, 25 percent and 15 percent higher than those of theAmericanSSTandwereincreasingrapidly,

In1967,with theselectionof theBoeing-GeneralElectricswing-wingmodelastheAmericanSST’sdesignattheveryendof1966,thewholeUSdecisionmakingstructurefortheSSTprogrammebegantochange.

Americandesignsbegintotakeshape.A slimming down of the proposed models resulted in the NAC-60 and

Curtiss-Wright efforts being dropped from the programme, with bothBoeing and Lockheed asked to offer SST models meeting the moredemanding FAA requirements and able to use either of the remainingenginedesigns.InNovember,anotherdesignreviewwasheld,andbythistimeBoeinghad scaledup the original design into a 250-seatmodel, theModel 733-290. Due to concerns about jet blast, the four engines weremovedtoapositionunderneathanenlargedtailplane.Whenthewingswereintheirswept-backposition,theymergedwiththetailplanetogiveadelta-wingplanform.

AirVehicleTwodemonstratesverygraphicallyBernoulli’sprinciplewherebycondensationbecomesvisibleovertheuppersurfaceofawingcausedbyapressuredropduetoairaccelerationoverthe

uppersurfaceasitcomesintolandatEdwardsAFB.Itsoundshighlytechnical,butlooksabsolutelyamazing!(USAF)

OnemorelandingatEdwardsbyAV1,withthreebraking‘chutesstreaming.(USAF)

Both companies were now asked for considerably more detailedproposals, tobepresentedforfinalselectionin1966.Whenthisoccurred,

Boeing’sdesignwasnowthe300-seatModel733-390.BoththeBoeingandLockheed L-2000 designs were presented in September 1966 along withfull-scale mock-ups. A lengthy review followed, and on December 31,1966,Boeingwasannouncedasthewinner.Thedesignwouldbepoweredby the General Electric GE4/J5 engines. Lockheed’s L-2000 was judgedsimpler to produce and less risky, but its performancewas slightly loweranditsnoiselevelsslightlyhigher.

The SST mock-up included both overhead storage for smaller itemswithrestrainingnets,aswellaslargedrop-inbinsbetweensectionsoftheaircraft. In themain247-seat tourist-classcabin, theentertainmentsystemconsistedof retractable televisionsplacedbetween every sixth row in theoverheadstorage.Inthe30-seatfirst-classarea,everypairofseatsincludedsmallertelevisionsinaconsolebetweentheseats.Windowswereonlysixinchesduetothehighaltitudestheaircraftflewatmaximizingthepressureonthem,buttheinternalpanewastwelveinchestogiveanillusionofsize.

Boeing predicted that if the go-aheadwere given, construction of theSSTprototypeswouldbegininearly1967andthefirstflightcouldbemadeinearly1970.Productionaircraftcouldstartbeingbuiltinearly1969,withtheflighttestinginlate1972andcertificationbymid-1974.

The PAC did not formally meet again after December 1966. SSTdecisions now became more programmatic, centering on relations withcontractors and on technical problems - especially on the fact that thewinning swing-wing design was not economic and on the two-yearreassessment by Boeing resulting in the firm selecting a new fixed-wingSST design in 1969. High level and wide-ranging policy discussions onsuch issues as overall design selection, the sonic boom, economicperformance, and project financing were infrequent. In the same veinAmerican officials began to view the Concorde more passively, anddiscussions about theConcorde threat diminished considerably. The FAAcontinued to monitor the Concorde’s development, but the intelligenceeffort became less focused and more irregular and the CIA’s rolediminished. In addition, the usefulness of the raw intelligence on foreignSST programs from theCIA and the StateDepartmentwas questionable,sincethisdatausuallyaddedlittletowhatwasalreadyknowpublicly.

Takenfromoneofthechaseaircraft,62-0001withthewingtipsinthemid-waypositionbanksawayfromthecamera.ThepicturewasfromthedaysinservicewithNASA.(USAF)

The first Concorde prototype was unveiled on 11 December 1967 atToulouse, France. In the US, the FAA and its SST contractors workedstrenuously to counter the resulting publicity from the unveiling. Boeingcontacted twenty media people in Washington, DC - includingrepresentatives from the Washington dailies, the three major televisionnetworks.Time,Newsweek, and theWall Street Journal - to supply themwithbackgroundinformationandapictureofthenewlydesignedAmericanSST.

TheSSTproject continued, but the negative publicity associatedwiththe tests and spiralling costs brought the cancellationof theBoeing2707projectandledtotheUnitedStates’completewithdrawalfromSSTdesign.

In March 1971, despite the project’s strong support by theadministrationofPresidentRichardNixon, theUSSenate rejected furtherfunding.Acounter-attackwasorganizedunderthebannerofthe‘NationalCommitteeforanAmericanSST’,whichurgedsupporterstosendin$1tokeeptheprogrammealive.Afterward,lettersofsupportfromaviationbuffs,containing nearly $1 million worth of contributions, poured in. Laborunions also supported theSSTproject,worried that thewindingdownofboth the Vietnam War and Project Apollo would lead to massunemployment in the aviation sector. The President of the AmericanFederation of Labor and Congress of Industrial Organizations, GeorgeMeany suggested that the race to develop a first-generation SST wasalready lost, but the US should ‘...enter the competition for the secondgeneration—theSSTsofthe1980sand1990s’.

In spite of this new found support, Congress also voted to end SSTfundingon20May1971.

The XB-70 had played an important part in doing a lot of thegroundworkfortheAmericanSST-butpoliticsandback-stabbingensured

thatitreallywasaMach-numbertoofar.

RETIREMENT

The final B-70 flight, NASA Flight 23, was scheduled for an 08:00departureon22January1969.Thiswasdelayeduntil4Februaryforworkonexcitervaneanditsassociatedsensors.

Then at 10:57 on 4 February, the last surviving B-70 rotated andclimbedupandawayfromwhathadbeenitshomeforfouryearsandfivemonths,EdwardsAFB.Itsdestinationwas theU.S.AirForceMuseumatWright-PattersonAFBnearDayton,Ohio.

Twoof its sevenpilots,FitzFultonandTedSturmthal, commanded iton its last flight. Even on that final flight, the XB-70A recorded flightresearchdata;shaker/excitervaneandILAFdatawasrecordedduring thethreehourand18minuteflight.The1,880-statutemiletripwasflownat.91Machsubsoniccruiseat33,000feet.Nosupersonicdashoccurred.Priortoits final landing it made a farewell pass low over the field. At 14:15 ittouched down, popped its drag chutes, rolled out its momentum, andstopped.Itthentaxiedbehindafollow-mevehicletowhereinstructedandshutdown.

In theceremony that followed,pilotFulton turnedover its logbook tothemuseum’s curator. Then he and copilot Sturmthal walked toward theawaitingcrewvan.Ifeithersneakedalookback,theynevertoldanyone.

Valkyrie Number One had carried on boldly since its sister ship hadperished.Thiswasits83rdflightanditslogbookshowedatotalflighttimeof 160 hours and 18 minutes. Considering the total cost of the B-70programmetoindustryandtheAirForce-$1.7billion-itcostabout$13.1millionperflight—thatis,consideringtwoXB-70Aairvehicles,flying129times.

It was this staggering cost thatmay have prompted Ted Sturmthal tosay:I’ddoanythingtokeeptheB-70intheair—exceptpayforitmyself.

‘Fitz’FultonleadsTedSturmthalclimbingtheladderandintothecockpitof62-0001forthelasttime.Theexcitervaneinstalledforthelastflightisclearlyvisible.(NAARockwell)

ThearrivalatWright-PattersonAFBfromEdwardson4February1969.Afterhandingoverthelog-book,thecrewwalkedaway.Littledidanyonerealisethattheaircraftwouldremainoutsideinthe

harshOhioclimatefornineteenyears.(NAARockwell)

TheaircraftwasplacedonoutdoordisplayatWright-Patterson’sAreaC,wheretheU.S.AirForceMuseumwasthenlocated,adjacenttothecityof Fairborn. It soon became amajor attraction, drawing visitors from farandwide.

The XB-70 did not remain in place for very long, for in June 1970,construction of a new facility for themuseum began at a site about fivemilesaway,ononeofWrightField’snowunusedrunways.InOctoberandNovemberof1970,wellbeforethenewbuildingwascompleted,theXB-70and thirty-seven of the museum’s other aircraft were towed off the basefrom the oldmuseum at Patterson Field, along local and state roads andfreeways, to the new museum at Wright Field. The route covered someeightmiles,crossingoverload-limitedbridges,underheight-limitingpowerlines,andbetweenspan-limitingpolesandotherobstacles.

Moving theXB-70over this route presented thegreatest challengeofall. The Valkyrie’s length needed to be considered, but its 105-footwingspanwasofgreatconcern.Theaircraft’sheightalsohadtobefactoredinto themove, but this was helped by the removal of the twin verticals.Weightwasthemostseriousproblem–theXB-70hadanemptyweightof262,000pounds,wellabovetheallowableloadforthefreewaybridgeithadto be towed across to reach the new museum site. Removal of the sixengines, the air conditioning system, and practically everything else thatcouldbetakenoutreducedtheValkyrie’sweighttoaround147,000pounds,whichwaswithinthedesignlimitsofthebridge.

ThemovefromWright-PattersonAFBtoWrightFieldwasfraughtwithproblems.SignsandwireshadtobemovedandtheaircraftweightreducedbyalmosthalftoallowittogooverRoute444BridgenearMadRiver.Theproblemsherewerecompoundedbyonlyaneight-inchclearance

betweencurbandmainwheels!(bothUSAFMuseum)

Eventually,theaircraftreacheditsnewparkingareaandwasproudlyon

display when the newly completed US Air Force Museum facility wasdedicatedinSeptember1971.

TheXB-70wasdestinedtoremainthereonoutdoordisplayforanotherseventeenyears.Over timethemachine tookon theroleofUSAirForceMuseumlogo,parkedas itwasfacing themuseum’saccess road.On twooccasions it was repainted and each time inspections by the museum’srestoration division staff noted some degree of deterioration anddelamination.

AirVehicle1getsclosetothenewAirForceMuseumsite-Route444doesnotoftenseetrafficlikethis!(USAFMuseum)

Moves,bubbles,blistersanddingsThemostnotabledeteriorationwaswherecertainareasonthefuselageandunderside showed evidence of spot delamination of the stainless steelhoneycombskinpanels.

This delamination has been characterized by bubble-like ‘blisters’ onthefuselagearoundthewingapexandsimilarblistersonthebottomofthe

main centre section.Certainly it is true that the delamination process didnotbeginwiththeXB-70sretirementtotheUSAirForceMuseum,foraswehavealreadyseen,somedelaminationoccurredduringtheflighttestingprogramme. However, given that the aircraft was parked outside in anenvironmentthathasanannualtemperaturegradientof-20°Ftowellover100° F for nineteen years, it is not surprising that the deterioration wasgradual,butprogressive.

Thisdeteriorationwasnothelpedbythefactthatevenaftertheaircraftwas supposedly permanently installed in the Museum’s second majorexhibitsbuilding-dubbedtheModernFlightHangar-itwasstillsubjecttoa series of moves over the years and as anyone involved in aircraftpreservationknows-aircraftmovesincreasesthelikelihoodofhangarrash!

62-0001istowedalongOhioRoute444pastthehistoricHuffmanDam.(USAFMuseum)

XB-70Avalkyrie62-0001posesnose-to-nosewiththeRockwellB-1A(USAFMuseum)

Whenevertheaircraftwasstrippedandrepaintedithadtobetakenoffdisplayandmovedtoanotherareawheretheworkcouldbedoneinsafetyawayfromthepublic.Whenthejobwascomplete,theXB-70wastowedtoa special area for update photography, then back to the display area - around trip of about two miles. Shortly after the museum acquired the

RockwellB-1Aitwasagaintowedtothephotographyareaandposednose-to-nosewiththeB-lbeforebeingmovedbackagaintothedisplaypositioninfrontofthemuseum.

Also,theyear-to-yearrepositionofoutdoordisplayaircraftforcedothermovesoftheXB-70.Eachtimethat theaircraftwasmoved,extremecareanda large,heavy-duty tugwere requiredand the landinggearhad tobepositioned on steel plates to prevent the wheels from sinking into thetarmac.Duringonesuchmove,atyreonamaingearwheelcaughttheedgeofoneofthesteelplatesandblewout.Fortunately,noonewashurt.

BeforetheModernFlightHangarcouldbeopenedtothepublic,agreatdealofpreparationandshufflingofaircraft tookplace.Before theXB-70wentintotheModernFlightHangar,itwastowedtotherestorationhangarforsomeroutinemaintenance.Astheaircraftenteredtherestorationhangar,themovementcrewheardaloudbang,followedbythefrighteningsightofnumerousmetal shards falling from the nose gear well. After giving thearea an inspection, the crew concluded that a metal conduit support hadfracturedbutposednostructuralintegrityproblem.

TheValkyriewas towed into thenorthendof thedisplayhangarnosefirst.On the first attempt itwasdiscovered thather twin tailswereabouttwoinches tootall toclear thehangardooropening.Rather thanresort tothe removal of the vertical tails, the restoration crew doing the movingfoundasimplersolution:deflate themaingearstrutsand fully inflate thenose gear strut. That pushed up the nose and lowered the tail, whichallowedmorethananinchoftailclearancetotowtheairplaneintodisplayposition.

Over the next fewyears, theXB-70was temporarilymoved outdoorsseveral times so that additional aircraft could be pulled into theModernFlightHangar.Always,itwasreturnedtoitsprominentdisplayareainthenorthendofthehangar.Interestinglyenough,aftertheairplanewassafelyinstalled in the Modern Flight Hangar, several groups of XB-70 buffssuddenlybecameinterestedintheaircraft’sstateofpreservationandbeganto express to the museum their concerns regarding the delaminationproblem,muchtotheMuseum’sannoyance.

The standard answer given out over the years byMuseum staff, andreiterated in Joe Ventolo Jnr and Jeanette Remak’s 1998 book XB-70Valkyrie The Ride to Valhalla is that the honeycomb construction isextremelystrongandafewflawswouldnotbesignificant.Besides,theAV

1 had only the first in a series of refinements of the honeycombconstructionprocesses.No,theValkyriewasabsolutelynotgoingtocomeapartdespiteafewpoppedlaminationbonds.

This Iwould seriously question, for a number of reasons. Firstly, theXB-70wasnotknownas‘Cecilthesea-sickseaserpent’fornothing.Lookatanyvideooftheaircraftmovingandyoucanclearlyseethenoseoftheaircraftbouncingupanddownatexactlythesametimeastheaircraftnosewheelscrossoverjointsintheconcretetaxiways.Notonlydoesitmoveatthesametime,themovementismagnifiedbythelever-armmomentoftheentire structure above and ahead of the nosewheel,which is acting as afulcrum.Thefurtherawayfromthepivot-point(thenosewheel)thegreaterthemovement.

Thisisjustsimplehighschoolphysicsoffulcrums.Afulcrum,orpivotpoint,istheareaaroundwhichaleverturns.Forittowork,therearetwodistances-‘levers’-awayfromthepivotpoint-onelong,oneshort.Aleverisalength-ordistanceusedtoputoutforceormaintainweightatoneend,while pressure is exerted on its second end. Think of a crowbar used tomovealargerock-movetheendofthecrowbarthefurthestawayfromtherockanditmovesalongwaycomparedtotheendtouchingtherock,butinreducingtheamountofmovement,theforceappliedismagnified.

Alineofdelaminationblistersjustbelowhorizontalofthefuselagecrosssectionof62-0001intheNationalMuseumoftheUSAFatDaytonOhioin2001.

Theareashowninthephotographisaboutfifteenfeetlong,spreadeithersideofthefrontfuselagejoin-eachblisterscalestoanareaabouttwelveinchessquare-somewhatmorethan‘afewpopped

laminationbonds’Ithink!(author)

ClearlyNorthAmericanexpectedproblemswithdelaminationofthestainlesssteelhoneycomb,forthisisjustoneoftheapproved‘repairs’tothestainlesssteelhoneycombpanelsusingdoublers,a

plugandweldedpins.(NorthAmericanRockwell)

Anotherviewofthesamedelaminatedarea,thistimelookingupfromunderneath,whichgivesabetterideaastohow‘high’eachblisteris.

InrecentyearsaviationmuseumsinGreatBritain-inparticularthedeHavillandHeritageCentre-haveundertakenaprogrammeofultrasonicallytestingtheirlaminatedand/orcompositeaircraft

structurestobetterdetermine‘whatisgoingon’insidethem.TheDHHeritageCentreweresurprisedattheirdiscoveries-IdonotknowiftheXB-70hasbeensotested,butifso,Iwouldlovetoseethe

results!(author)

The same applies to the unsupported end of the nose of the XB-70.Movethenose-tipagreatdistancebybumpingtheaircraftoverhangardoorsills, drain covers, over joints in concrete slabs, and a smallermovementbutgreatlymagnifiedforceisappliedtotheotherend-inthiscasetheareaaroundandabovethecentre-sectionattheapexofthewing-box.Anyforceappliedtowhatisbasicallyafixedstructure-eveniftheaircraftisatrest-istranslatedinto‘stress’-andstresswillalwaysseekouttheweakestpointofanygivenstructure.

Theareaof thefuselage in thevicinityof theapexof thewing-boxisbasicallycircularincross-section.Thismeansthattheunsupportednoseis‘hangingoff’thisarea-thereforethetopofthecross-sectioninthiszoneisundertension,andthebottomundercompression.Theforcesfeedingbackfromthenosewilltendtowantto‘pushout’thestructureatthehorizontalpart of the structure, which is exactly where a long line of delaminationblisterscanbeseen.

DuringaSeptember1992visittotheMuseumIwas‘tippedoff’thattherehadbeenproblemsdiscoveredinthenosewheelbay.

SurreptitiouslyItookthisphotographbyflashlooking‘straightup’intothenosewheelbay.Istillcannotseeanydamage,butIhavebeenassureditisthere!(author)

Another problem generated by years of outdoor display andmiles oftowingforonereasonoranothercausedagreatdealofwearandtearontheValkyrie’styres.NotlongaftertheXB-70movedindoors,alltentyreswerereplacedwithasetofsparesreceivedwiththeaircraft.Eachwasfilledwithaurethanerubbercompoundtoeliminatetheneedtoservicethemregularlywithhigh-pressureair.Thisprocessalsocompletelyeliminatedtheriskofanytyrehavingahighpressureblow-out.

Thenextproblemtostriketheaircraftoccurredin1992,whentheUSAir ForceMuseumwas to receive a temporary but very large exhibit offormer Soviet space hardware and requiredmore than the 20,000 square

feetoccupiedbytheXB-70.ItwasplannedthattheXB-70wouldbemovedfromtheModernFlightHangarandputbackoutdoorsagainforthesixoreight months the Soviet Space Exhibit would be in place. Just prior tomoving the XB-70 out of the hangar, however, the nose gear well areawhere the supposedly fractured conduit support had been noted severalyears earlier was given a further inspection. Far from being a brokenconduitsupport,whathadactuallyfracturedwas thenosegeardragbracesupport bracket. Aircraft structures engineers who looked at the damagebelievedthatanyfurthermovementwhatsoeverof theXB-70couldresultincollapseofthenosegear.Itwasamiraclethatthegearhadnotcollapsedduring one of the earlier moves of while the aircraft was on display.Immediately,a jackpadwasaffixed to the fuselage jackpoint forwardofthe wing apex, and a large hydraulic jack stand was put in place. OtheraircraftmadewayfortheSovietSpaceExhibit,buttheValkyriecouldnotbemovedagainuntilrepairsweremade.

Therepairstooknearlyayear.Meanwhile,thejackundertheXB-70sforward fuselage was turned into a display item with the addition of amannequin clad in a North American maintenance technicians coveralls.Thebrokenbracketwasremoved,measured,andreplaced.Thenewbracketwascheckfitted,thenheattreated,andfinallyreinstalled.Althoughthenewbracketwasnotairworthy,itwassaidbyitsreplicatorstobestrongerthantheoriginalandabletotakethestressesoftowing.Interestinglyenough,theValkyriewasnotmovedfornearlyfiveyearsaftertherepair.

The National Museum of the US Air Force still move the aircraftaround,thenosestillunsupported.WheneverIgetovertoseeit,I’mneverquitesurewheretolook.Atthetimeofwriting,‘Cecil’isintheResearch&Development/FlightTestGalleryawayfromthemainmuseum,locatedonthe controlled-access portion of Wright-Patterson Air Force Base,accessibleusingtheshuttlebusservicefromthemainmuseumcomplex.

62-0001insidetheR&D/FlightTestbuildingonthefarsideofWrightField,surroundedliterally-by

otheraircraft.(author)

Noseseekingoutthesunandair-XB-7062-0001looksoutoftheR&DHangaratWrightField.(author)

TheNorthAmericanXB-70AValkyriewasandisalegend.Itisapricelesspieceofaeronauticalengineeringandaworkofart.

Asamannedbomber,theB-70diedininfancywithouttheopportunitytoproveitsworth,overtakenbytheprogressforwhichtheB-70itselfhadbecomeasymbol.TheB-70wasawatershedprojectcoveringmanyyearsofmajordevelopment,tensofmillionsofmanhours,andnearlytwobilliondollars.

It was, more than anything, killed off by one man - Robert StrangeMcNamara.HekilledtheB-70,justashewasthemaininstigatorinkillingofftheAmericansupersonictransportproject.MacktheKnifeisgonenowyetthelastunique,futuristicB-70canbefoundsittinginthatR&DhangaratWrightField,lookinglonginglytowardsthesunlight.

‘Cecilthesea-sickseaserpent’stilllookslikeit’sgoingsupersonic!

XB-70AFLIGHTTESTLOG

ABBREVIATIONS

ADS AccessoryDriveSystem.AMC AirMaterielCommand.ACTS AirCorpsTacticalSchool.AEDC ArnoldEngineeringDevelopmentCenter.AICS AirInletControlSystem.ALBM Air-LaunchedBallisticMissiles.ARDC AirResearchandDevelopmentCommand.AWPD AirWarPlansDivision.AFFTC AirForceFlightTestCenter.AMPSS AdvancedMannedPenetratingStrategicSystem.BLC BoundaryLayerControl.BTU BritishThermalUnit.CAF ContinentalAirForce.CBO CombinedBomberOffensive.CIA CentralIntelligenceAgency.CPB ChemicallyPoweredBomber.DEI DevelopmentEngineeringInspection.DoD DepartmentofDefense.FY FiscalYear.FOD ForiegnObjectDamage.GHQ GeneralHeadquarters.GOR GeneralOperationalRequirement.HEF HighEnergyFuel.IBM InternationalBusinessMachines.IFF IdentificationFriendorFoe.ICBM IntercontinentalBallisticMissile.IOC InitialOperationalCapability.JP JetPetroleum.

JCS JointChiefsofStaff.L/D Lift/Drag.LRL LawrenceRadiationLaboratory.M&TC MissionandTrafficControl.MAD MutuallyAssuredDestructionMBA MastersofBusinessAdministrationMPB MissilePlatformBomberNAA NorthAmericanAircraftNACA NationalAdvisoryCommitteeonAeronauticsNASA NationalAeronauticsandSpaceAdministration.NORC NationalOpinionsResearchCenter.NSBP NationalSonicBoomProgram.OP OperationalPlan.OSS OfficeofStrategicServices.PPBS Planning,Programming,andBudgetingSystem.RAM RadarAbsorbantMaterial.RBS RecoverableBoostSystem.RCS RadarCross-Section.RFA RequestForAlterations.RTD&E Research,Test,DevelopmentandEvaluation.SR StudyRequirement.ST SolutionTreated.SAC StrategicAirCommand.SST SupersonicTransport.STA SolutionTreatedandAged.SLAB SubsonicLowAltitudeBomber.TF-X TacticalFighter‘X’.USAAC UnitedStatesArmyAirCorps.USAAF UnitedSatesArmyAirForce.USAF UnitedStatesAirForce.VG VariableGeometry.VGH Velocity-Gravity-Height(datarecorder)VSS SovietAirForce

WS WeaponSystem

WSPO WeaponSystemProjectOffice

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Danger and Survival—Choices about the Bomb in theFirst 50 Years.McGeorgeBundy; RandomHouse,1988.

Dark Eagles: A History of Top Secret U.S. AircraftPrograms.CurtisPeebles;PresidioPress,1995.

DeepBlack.WilliamEBurrows;BerkeleyBooks,1986.Developmental Program Manual, XB-70A (Propulsion

System),USAF,July30,1966.

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Development of the XB-70 Propulsion System. EdwardFreschel Jr. and Elbert S. Steel; North AmericanAviation,LosAngeles,CA,November1965.

From Huffman Prairie to the Moon: The History ofWright-Patterson Air Force Base. Lois E WalkerandShelbyE.Wickam;Hq.Wright-PattersonAFB,OH:AirForceLogisticsCommand,1985.

Ground Support Equipment, North American Aviation,LosAngeles,CA,1960.

In Retrospect: The Tragedy and Lessons of Vietnam,Robert S. McNamara with Brian VanDeMark.;TimesBooks,1995.

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Iron Destinies/ Lost Opportunities: The Arms RaceBetweentheUSAandtheUSSR1945-1987.CharlesMorris;HarperRow,1988.

IronEagle:TheTurbulentLifeofGeneralCurtisLeMay.

ThomasMCoffey;CrownPublishers,1986.JFK and Vietnam. John M Newman; Warner Books,

1996.Jane’sAll theWorld’sAircraft,Mcgraw-Hill,NewYork,

N.Y.,1966.Lessons from the XB-70 as Applied to the Supersonic

Transport. Fitzhugh Fulton Jr.; NASA FlightResearchCenter,EdwardsAFB,October1968.

LockheedAircraft Since 1913. René J.Francillon;NavalInstitutePress,1987.

Lockheed Martin’s Skunk Works. Jay Miller; MidlandPublishing,1995.

Mayday: Elsenhower and the U-2 Affair. Michael RBeschloss.HarperRow,1986.

Mission with LeMay:My Story. Gen. Curtis E. LeMay,with MacKinlay Kantor. Doubleday & Company,1965.

New Evidence of the Soviet Supersonic TransportIntelligence Memorandum, Directorate ofIntelligence,CentralIntelligenceAgencyMay1967.

New Weapons-Old Politics: America’s ProcurementMuddle. Thomas L McNaughton; BrookingsInstitution,1989.

North American Aviation, Inc. B-70 Research Program

Objectives:TFD-65-575,1965.North American Aviation, Inc. The Recon-Strike B-70

WeaponSystem‘GO’Plan.1961.North American XB-70: Half Airplane-Half Spacecraft.

PartsOneandTwo,ThomasGFoxworth;HistoricalAviation Album, Volume 7, 1969 and Volume 8,1970.

Promise and Power: The Life and Times of RobertMcNamara. Deborah Shapely; Little, Brown andCompany,1993.

PublicPapersofthePresidents—JohnF.Kennedy,1961-1963.U.S.GovernmentPrintingOffice,1963.

Safe,Secure,andSoaring—AHistoryoftheFederalCivilAviation Administration Policy—1967-1972,RichardKentJr.U.S.DepartmentofTransportation,1980.

Seven Decades of Progress: A Heritage of AircraftTurbine Technology. Leonard A Dalquest, Eric R.Falk,etal./ed.AeroPublishers,1979.

Shield of Faith. B. Bruce Briggs; Simon and Schuster,1988.

Skunk Works: A Personal Memoir of My Years atLockheed.BenRRichandLeoJanos;Little,BrownandCompany,1994.

Soviet SST: The Techno-politics of the Tupolev-144.HowardMoon;OrionBooks,1989.

Structural Design of the XB-70. Richard L. Schleicher;NorthAmericanAviation,Inc.,1967.

TheAirForceMuseum.Dayton,OH:NickP.AppleandGeneGurney.TheCentralPrintingCompany,1991.

The B-70 Valkyrie Story. Douglas L. Emmons; TheUnitedStatesAirForceMuseum,1980.

The Central Intelligence Agency and OverheadReconnaissance - the U-2 and Oxcart Programs1954-1974 Gregory W Pedlow and Donald EWelzenbach,CentralIntelligenceAgency

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The collection of papers in the Air Force Flight TestCenterHistoryOffice,EdwardsAFBThecollectionof papers in the NASA Dryden Flight ResearchCentre.

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TheEssenceofSecurity:ReflectionsinOffice.RobertS.McNamara;HarperandRow,1968.

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The Great White Bird. Steven Pace; Air ClassicsQuarterlyReview,ChallengePublicationsVolume4,Number3;Fall1977.

The Manned Missile: The Story of the B-70. Ed Rees;SloanandPearce,1960.

The National Security Act: A Blueprint for theCongressional Role in Weapons Development.” (ACase Study of the B-70 Bomber Program.) DennisSherman;UniversityofWisconsin,1978.

TheOfficeoftheSecretaryoftheAirForce,1947-1965.George M Watson; Center for Air Force History,1993.

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TheThumpofDisaster:TestPilotRecalls1966Crashofthe B-70 Bomber. Marvin Miles;The Los AngelesTimes,1966.

The U-2 Affair. David Wise and Thomas B. Ross;RandomHouse,1962.

The United States Air Force: A Turbulent History.HerbertMolloyMasonJr.Mason/Carter,1976.

TheUnitedStatesAirForce:BasicDocumentsonRolesandMissions.(AirStaffHistoricalStudy.)RichardIWolf;OfficeofAirForceHistory,1987.

The War Profiteers. Richard Kaufman; Bobbs MerrilPress,1970.

The Whiz Kids: Ten founding fathers of Americanbusiness—and the legacy They left us. John AByrne;Doubleday,1993.

Titanium Fabrication Technique for the XB-70 andBeyond North American Aviation. Wayne AReinsch; Society of Automotive Engineers,Aeronautics Space Engineering andManufacturingMeeting,LosAngeles,CA,October3-7,1966.

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1987.TriplesonicTwosome.StevePace;Wings,SentryBooks,

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US Bombers: 1928 to 1980s. Lloyd S Jones; AeroPublishers, Inc., Fallbrook, California, SecondEdition,1980.

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XB-70 Pilots Describe the World of Mach 3. RichardSlawsky; Airline Management and MarketingMagazine, Parts One and Two, March and April1967.

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XB-70 Program Engineering Effort to be Accomplishedon Contract AF33(600)-42058 (31 July 1962through 30 June 1964), North American Aviation,Inc.September8,1962.

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