CHAPTER-2LITERATURE REVIEW

2.1 Early Experiments (1907-1939)

Even before World War I, during the first decade of powered

flight, the idea of an unmanned automatically controlled "flying

bomb" or "aerial torpedo" circulated in a number of countries.

The technology making such a device possible consisted of

gyroscopes mounted in contemporary airframes. [1] The first

practical efforts on record began when Peter C. Hewitt, inventor

of the mercury vapor lamp, approached Elmer A. Sperry of Sperry

Gyroscope Company in April 1915 with the idea of a “flying bomb”.

[2] Together they developed and tested an automatic control

system on both a Curtiss flying boat and a twin-engine aircraft.

[3] This particular system showed enough promise by the summer of

1916 to merit a test with an official observer. In August, Elmer

Sperry wrote to Lieutenant Colonel George O. Squier of the Signal

Corps, but the Army did not answer. [4] Consequently, the two

inventors arranged an official trial with the Navy. On 12

September 1916, Lieutenant T. W. Wilkinson, Jr. (USN), with

Sperry's son Lawrence as pilot, took off aboard a specially

equipped seaplane. Under automatic control, the aircraft climbed

to a predetermined altitude, held a satisfactory compass course,

flew a set distance, dove, and would have impacted as planned had

Sperty not intervened. [5]

2.2 World War I

2.2.1 Kettering “Bug” Aerial Torpedo (1918)

The Kettering Aerial torpedo was the first U.S. Purpose-

built cruise missile. It was invented by Charles F. Kettering,

founder of the Delco Division of General Motors and holder of

over 140 patents including the automobile self-starter.

Kettering’s design was developed and builds by the Dayton Wright

Airplane Company in 1918 for the Army signal Corps. The unmanned

Bug took off from a trolley which ran along a launch track.

Target coordinates were preset prior to launch. Heading was

maintained by a primitive autopilot and range to target was

determined by an engine rev-counter. When the required number of

engine revolutions was recorded, a control closed an electrical

circuit which shut off the engine. The wings were then released

and the Bug dived to earth where its 180 pounds of explosive

detonated on impact. Although the testing of the Bug was

successful, World War I ended before the missile could enter

combat. System testing continued until 1920 when the project was

terminated due to lack of funds.

2.3 Between the Wars (1919-1939)

2.3.1 Argus and Schmidt Pulsejet Developments and the origins of

the V-1 (Germany)

The immediate ancestor of the V-1 Cruise Missile was a

pilotless bomber aircraft called the Fernfeuer (Long Range Fire)

that was proposed in 1939 by Dr. Fritz Gosslau of the Argus Aero

Engine Company. The Fernfeuer was a piston-engine, recoverable

pilotless bomber capable of delivering a 1-ton bomb to the target

and returning to base. The aircraft was gyro-guided to the target

where an accompanying director aircraft provided radio-commanded

terminal course correction and issued the bomb release command.

The Fernfeuer aircraft would then automatically return to base.

The project was abandoned due to urgent priorities for the

conduct of the war. Gosslau did not give up and in 1941 Argus

proposed a pulse-jet-powered cruise missile which became the V-1.

2.4 World War II Developments – Germany (1939-1945)

Although Nazi Germany produced the first modern cruise

missile, the V-1, both Germany and the United States pursued a

number of less-advanced cruise missile concepts where many

reached limited operational use throughout the World. The

Luftwaffe, in an attempt to solve the problem of killing hard

targets in the enemy rear area, developed the bizarre Mistel

composite aircraft in which a pilotless converted bomber was

connected to a piloted fighter as a recoverable terminal guidance

system. The Luftwaffe employed with some success, a number of

Air-to-Surface Anti-ship Missiles which were primarily short

range glide or boost-glide vehicles. Although never incorporated

into cruise missiles, the Luftwaffe Design Bureau run by the

Horten Brothers developed jet-propelled flying wing prototypes

which incorporated low observables shaping the primitive radar-

absorbing materials.

•V-1 (Fiesler F-103) Cruise Missile

•Ground Launch Version

•Air Launch Variants

•Piloted Variants

•Mistel Composite Aircraft

• Air-to-Surface Anti-ship Missiles

•Stealth – 1944

2.4.1 Ground Launch V-1 on Ski Site Catapult

The Fiesler F-103 (V-1) was the first modern cruise missile.

The key technology for the V-1 was the development of the Argus

Pulse-jet engine, a relatively simple propulsion system which

could be mass-produced at low cost and which provided the V-1

with a top speed equal to or higher than most of the allied

propeller-driven fighters of the day. The V-1 was a relatively

simple design which could be produced in large quantities by low

skill slave labor. Guidance was provided by a magnetic compass

for azimuth and a propeller-based rev counter which resulted in a

very large CEP at the target. The basic V-1 was ground-launched

from a gas or steam catapult from a fixed rail launcher. Allied

Intelligence analysts dubbed these launch facilities “ski

sites”because of the ski jump shape of the launch rail in

overhead reconnaissance photography.

2.4.2 Heinkel He-111H as Operational Air Launch Platform (1944)

The inherently low survivability of the fixed V-1 ground

launchers and the increasingly poor target access with the Allied

advances after D-Day led to the operational deployment of a

previously developed air-launched V-1 and a modified Heinkel He-

111H bomber as the initial launch platform. The air-launched V-1

partially improved the survivability and range problems of the

ground launched version but further worsened the missile’s CEP.

2.4.3 Jet Bomber Air Launch V-1 Options

The rapid development and operational deployment of the

Arado Ar 234 Blitz jet bomber in 1944 provided another potential

platform for the air-launched V-1. The high speed and resulting

high survivability of the Ar 234 provided the potential for

deeper penetration of Allied air space which enabled V-1 attacks

on rear area targets. Several launch configurations were

developed for the Ar 234/V-1, including tow bars, vertical

carriage with controllable dolly system and the definitive dorsal

launched configuration (the Huckepack) which was ready for

operation in the final days of the war.

2.4.4 Piloted V-1 Variants

A radical approach to the solution of the poor accuracy of

the V-1 was the development of a piloted version called the

Reichenberg (Fi -103 Re 4) to provide a human terminal guidance

system. Although not strictly a suicide mission since the pilots

were provided with parachutes, the probability of crew survival

would not have been very high. Although the Reichenberg project

was eventually terminated due to the strong objections of the

Luftwaffe Command Structure (Supported by Albert Speer) against

near-suicide piloted missions, Reichenberg continued to develop

flight test engineering data for the basic V-1.

2.4.6 Mistel 1

During World War II, the Luftwaffe was faced with the

problem of destroying high-value hard targets (such as bunkers or

other fortifications) in enemy rear areas. This required high

accuracy delivery of a large special purpose warhead something

that was not possible with the early small cruise missile

designs. The Luftwaffe produced an innovative approach called the

Mistel in which a converted pilotless bomber or purpose-built

bomber derivative was equipped with a large (4300 kg) shaped

charge warhead whose metal jet could easily penetrate most

hardened structures. High accuracy terminal guidance was provided

by carrying a piloted fighter aircraft on the back of the bomber

which would separate shortly before impact and return to base.

The Mistel depicted in the chart is a converted Ju-88 with a

Messerschmitt Bf-109F fighter on top.

FigAn artist’s depiction of the Mistel 1

2.5 World War II Developments –USA (1939-1945)

2.5.1 JB-2 “Loon” (V-1 Buzz Bomb)

In the summer of 1944 the U.S. Army Air Force obtained

several examples of the German V-1 cruise missile which partially

survived impact in England. Army Air Force Technical Intelligence

at Wright Field exploited these specimens to produce a complete

set of reverse-engineered construction drawings. These were used

to develop a U.S. version of the V-1, designated the JB-2. Radio

command guidance was incorporated in the design which

significantly improved the large CEP of the V-1. The plan was to

produce 10,000 JB-2’s most of which were intended for use in the

Pacific to support an anticipated invasion of Japan. Although the

full scale production plan for the JB-2 was never executed, the

JB-2 was in production by early 1940, and 1400 + missiles were

produced by V-J Day. This adaptation illustrates how rapidly a

new foreign technology can be transferred and incorporated in

weapons if national survival is at stake and unconventional

development processes are employed. The JB-2 was also adopted by

the U.S. Navy and named the “Loon.” The JB-2/Loon was launched

from a number of land and ship platforms and formed the basis for

many U.S. post war cruise missile developments.

Fig

JB-2 “Loon” at U.S. Air force Museum

2.5.2 U.S. Navy Sub-Launched Loon – 1949

Starting in 1949 the U.S. Navy deployed the Loon cruise

missile on the modified U.S. submarine Carbonnero. A number of

Loons were launched from the Carbonnero until 1950 when it was

modified for the Vought Regulus I cruise missile test program.

Fig

Sub-launched Loon Info

2.6 Postwar Developments (1945–present)

2.6.1 Hellcat Strike RPV – 1952

The Grumman F6F Hellcat was the premier U.S. Navy carrier-

based fighter in the Pacific War. After V-J Day a small number of

Hellcats were converted to the F6F-5k multi-mission drone

configuration. The modification included the addition of a radio

command link, mission-specific instrumentation and wing tip fuel

tanks to extend the aircraft’s endurance. Hellcat drones were

used for nuclear cloud sampling for the Operation Cross Roads

atomic weapon testing at Bikini Atoll. During the Korean War

Hellcat strike drones operated by Guided Missile Unit 90 from the

USS Boxer were used to attack heavily defended targets such as

the bridge at Hungnam, Korea. The Hellcats typically carried a

2000-lb bomb and were controlled by a Douglas AD-4Q Skyraider

director aircraft.

Fig

Hellcat Strike RPV Info-graphics

2.6.2 MACE Land-Attack Cruise Missile US Air Force CGM-13 (1955-

1969)

The US Air Force provided Goodyear Aircraft (Akron) with 25

obsolete Matadors to modify for long range low altitude flight.

These old missiles were gutted, disassembled, and structurally

redesigned for the rigors of low altitude high-subsonic flight

with aerodynamic controls to permit rapid response to onboard

terrain following commands during mid-course flight. Airframe and

propulsion changes included: new wings with ailerons, new engine

inlet, completely new structure for the tail section, enlarged

body section to house and control added fuel, and a completely

new nose section for the ATRAN terrain guidance system. ATRAN

system located in the nose comprised a mission control computer,

and a radar altimeter autopilot based on a new Goodyear missile

X-band terrain avoidance radar. Mission planning systems

determined a selection of survivable flight paths, including

tactics to mislead enemy intelligence and detection devices.

After a successful series of development flight tests at White

Sands Missile Test Range, the Air Force awarded production to two

“associate prime” contractors: Goodyear for guidance, control,

mission planning, mobile ground systems, and training; and the

Glenn L Martin Company for the airframe, assembly and integration

of guidance, control, warhead, and propulsion. The first Mace

(CGM-13A) surface-to-surface missiles became operational in 1959

and used a guidance system permitting a low-level attack by

matching a radar return with radar terrain maps. The "B" series,

in service from 1961 to early 1970s, offered the option of high

or low attack using an unjammable inertial guidance system. Mace

"As" were phased out in the late 1960s, but some were used later

as target drones.

Fig

CGM-13 Info-graphics

2.6.3 XSM-64 Navaho Supersonic Intercontinental Cruise Missile

(1950-1958)

The Navaho intercontinental cruise missile has been called

the ultimate development of the German A-9/A-10 concept. When the

program was canceled in July 1957, missiles were in fabrication

for flight test. The Navaho and its comparable Soviet strategic

cruise missile programs were being rapidly eclipsed by the shift

of development resources to faster long range ballistic missile

with shorter times of flight and hence higher accuracy and

survivability. The Navaho program was terminated due to the

success of ballistic missiles that were relatively unstoppable in

light of the increasing air defense missile threat of the time.

Despite cancellation, the engines developed for the Navaho were

used, with minor modifications, for all the first generation of

American orbital rockets the Jupiter, Thor, Atlas, Titan I and

Saturn I. Versions of Navaho engines continue in use today in the

Atlas II and Delta III.

FigG-26 Navaho Info-graphics

2.6.4 La-350 Burya Supersonic Intercontinental Cruise Missile -

(1954-1960)

Soviet government decree on 20 May 1954 authorized two

parallel development programs by two aircraft design bureaus:

Lavochkin (Burya program) and Myasishchev (Buran program)

commissioned to develop intercontinental range supersonic cruise

missiles. Both missile designs wereto use ramjet engines and

astronavigation-aided inertial navigation. The Lavochkin-designed

Burya used liquid rocket boosters developed by Glushko whose

engines were used in space launchers and military ICBMs for the

next thirty years. The Burya was designed to carry a 2,350 kg

payload over an 8,500 km range. Despite cancellation of its U.S.-

equivalent Navaho and competing Myasishchev Buran, Burya testing

was continued through 1960, finally demonstrating cruise at Mach

3.2 over a range of 6,500 km with a 2,350 kg payload. With

development of Korolev’s R-7 ICBM going well, the Soviet

government canceled Lavochkin’s Burya due to its cost and

vulnerability. Nonetheless, the key technologies for an

intercontinental range cruise missile were proven.

FigLa-350 Burya Info-graphics

2.6.5 Northrop SM-62 Snark (1959–61)The Northrop SM-62 Snark was an early-model intercontinental

range ground-launched cruise missile that could carry

a W39 thermonuclear warhead . The Snark missile was developed to

present a nuclear deterrent to the Soviet Union and other

potential enemies at a time when Intercontinental ballistic

missiles (ICBMs) were still in development. The Snark was the

only surface-to-surface cruise missile with such a long range

that was ever deployed by the U.S. Air Force. Following the

deployment of ICBMs, the Snark was rendered obsolete, and it was

removed from deployment in 1961. The jet propelled 20.5 meter-

long Snark missile had a top speed of about 650 m.p.h. (1,046

kilometer/hour) and a maximum range of about 5,500 nautical miles

(10,200 kilometers). Its complicated celestial navigation system

gave it a claimed CEP of about 8,000 feet (2.4 kilometers).

The Snark was an air-breathing missile, intended to be

launched from a truck-mounted platform by two solid-fueled

rocket booster engines. The Snark next switched to an

internal turbojet engine for the rest of its flight. The engine

was a Pratt and Whitney J57, which was the first jet engine

featuring a thrust of 10,000 pounds or more. Since the Snark

lacked a horizontal tail surface, it used elevons

(aircraft control surfaces) as its primary flight control

surfaces, and it flew with an unusual nose-high angle during

level flight. During the final phase of its flight, its nuclear

warhead would have separated from its fuselage and then followed

a ballistic trajectory towards its target. Due to the abrupt

shift in its center of gravity caused by separation, the fuselage

would have performed an abrupt pitch-up maneuver in order to

avoid a collision with the warhead. One unusual capability of the

Snark missile was its ability to fly away from its launch point

for up to 11 hours, and then return for a landing. If its warhead

did not detach from its body, then the Snark could be flown

repeatedly.

Fig

SM-62 Snark missile rocket assist

2.6.6 Kh-55 (1983-present)

Kh-55 is launched exclusively from bomber aircraft and has

spawned a number of conventionally armed variants mainly for

tactical use, such as the Kh-65SE and Kh-SD, but only the Kh-

101 and Kh-555 appear to have made it into service. Contrary to

popular belief, the Kh-55 was not the basis of the submarine- and

ground-launched RK-55 Granat. It is powered by a single 400 kgf

Ukrainian-made, Motor Sich JSC R95-300 turbofan engine, with pop-

out wings for cruising efficiency. It can be launched from both

high and low altitudes, and flies at subsonic speeds at low

levels (under 110 m/300 ft altitude). After launch, the missile's

folded wings, tail surfaces and engine deploy. It is guided

through a combination of an inertial guidance system plus

a terrain contour-matching guidance system which uses radar and

images stored in the memory of an onboard computer to find its

target. This allows the missile to guide itself to the target

with a high degree of accuracy. The original Kh-55 had a drop-

down engine; the Kh-65SE had a fixed external turbojet engine,

whilst the Kh-SD had its engine inside the body of the missile.

Current-production versions are equipped with the increased power

of 450 kgf Russian-made NPO Saturn TRDD-50A engine. The Kh-

101 version has a low radar cross-section, of about .01 square

meters.

Fig

Kh-55

2.6.7 AGM-86 ALCM (1982-present)

The AGM-86 ALCM is an American subsonic air-launched cruise

missile (ALCM) built by Boeing and operated by the United States

Air Force. This missile was developed to increase the

effectiveness and survivability of the Boeing B-52H

Stratofortress bomber. In combination, the missile dilutes an

enemy's forces and complicates air defense of its territory.

All variants of the AGM-86 missile are powered by

a Williams F107 turbofan jet engine that propels it at sustained

subsonic speeds and can be launched from aircraft at both high

and low altitudes. The missile deploys its folded wings, tail

surfaces and engine inlet after launch. AGM-86B/C/D missiles

increase flexibility in target selection. AGM-86B missiles can be

air-launched in large numbers by the bomber force. B-52H bombers

carry six AGM-86B or AGM-86C missiles on each of two externally

mounted pylons and eight internally on a rotary launcher, giving

the B-52H a maximum capacity of 20 missiles per aircraft. An

enemy force would have to counterattack each of the missiles,

making defense against them costly and complicated. The enemy's

defenses are further hampered by the missiles' small size and

low-altitude flight capability, which makes them difficult to

detect on radar.

Fig

AGM-86B

2.6.8 AGM-129 ACM (1990-2012)

The AGM-129 ACM (Advanced Cruise Missile) was a low-

observable, subsonic, turbofan powered, and air-launched cruise

missile originally designed and built by General Dynamics and

eventually acquired by Raytheon Missile Systems. Prior to its

withdrawal from its service in 2012, the AGM-129A was carried

exclusively by US Air Force’s B-52H Stratofortress bombers.

In 1983 General Dynamics Convair Division (GD/C) was awarded a

development contract for the AGM-129A. The AGM-129A incorporated

body shaping and forward swept wings to reduce the

missile's radar cross section. The engine air intake was flush

mounted on the bottom of the missile to further improve radar

cross section. The jet engine exhaust was shielded by the tail

and cooled by a diffuser to reduce the infra-red signature of the

missile. To reduce electronic emissions from the missile, the

radar used in the AGM-86B was replaced with a combination of

inertial navigation and terrain contour matching TERCOM enhanced

with highly accurate speed updates provided by a Lidar Doppler

velocimeter.

Fig

An AGM-129 ACM of the United States Air Force

2.6.9 Tomahawk (1983-present)

The Tomahawk is a long-range, all-weather, subsonic cruise

missile named after the Native American axe. Introduced

by McDonnell Douglas in the 1970s, it was initially designed as a

medium to long-range, low-altitude missile that could be launched

from a surface platform. It has been improved several times, and

due to corporate divestitures and acquisitions, is now made by

Raytheon. Some Tomahawks were also manufactured by Boeing

Defense, Space & Security.

A conventionally configured cruise missile, the BGM-109 was

essentially a small, pilotless flying machine, powered by

a turbofan engine. Unlike ballistic missiles, whose aim point is

usually determined by gravity trajectories, a cruise missile is

capable of complicated aerial maneuvers, and can fly a range of

predetermined flight plans. Also, it flies at much lower

altitudes than a ballistic missile, typically with a terrain-

hugging flight plan. The trade-off for this low-observability

flight is strike time; cruise missiles travel far more slowly

than a ballistic weapon and the GLCM was typical in this regard.

GLCM was developed as a ground-launched variant of

the Tomahawk missile in use by the U.S. Navy (along with an

undeveloped air-launched version, the Medium Range Air to Surface

Missile [MRASM]. Unlike other variants of the Tomahawk, the GLCM

carried only aW84 thermonuclear warhead ; no conventional

capability was provided. The W84 warhead was a 0.2-

150kt variable-yield weapon. This yield contrasts with the yield

of the W80 warhead found on other versions of the Tomahawk and on

the ALCM from which the W84 was derived, which had a selectable

yield of 5 or 150 kiloton. The Pentagon credited the GLCM with a

range of 2000–2500 kilometers. Like other US cruise missiles of

this period, accuracy after more than 2000 km of flight was

within half the width of an American football field or 100 ft

(approximately 30 meters). The missile was entirely subsonic,

powered by a turbofan engine with a rocket assisting at launch.

Militarily, the GLCM was targeted against fixed targets—at the

outer edge of its range, the missile's flight time with its

subsonic turbofan was more than 2½ hours. The missiles were

launched from an elevated launcher, with the missile ejected from

its canister for about 13 seconds of solid rocket booster flight.

The fins extended at 4 seconds, the air inlet and wings deployed

at 10 seconds and the jet engine started at the end of the boost

phase. Flying at low level, the missile was guided

by TERCOM (terrain contour matching) to the target.

Fig

Tomahawk Cruise Missile Cutaway

Fig

Tomahawk Block –IV Cruise Missile

2.6.10 BrahMos (2006-present)

The BrahMos is a short range ramjet supersonic cruise

missile that can be launched from submarines, ships, aircraft or

land. It is a joint venture between the Russian Federation's NPO

Mashinostroeyenia and India's Defense Research and Development

Organization (DRDO) who have together formed BrahMos Aerospace

Private Limited. It is based on the Russian P-800 Oniks cruise

missile and other similar sea-skimming Russian cruise missile

technology. The name BrahMos is a portmanteau formed from the

names of two rivers, the Brahmaputra of India and the Moskva of

Russia.

It is the world's fastest cruise missile in operation. The

missile travels at speeds of Mach 2.8 to 3.0. The land-launched

and ship-launched versions are already in service, with the air

and submarine-launched versions currently in the testing

phase. An air-launched variant of BrahMos is planned which is

expected to come out in 2012 and will make India the only country

with supersonic cruise missiles in their army, navy, and air

force. A hypersonic version of the missile namely BrahMos-II is

also presently under development with speed of Mach 7 to boost

aerial fast strike capability. It is expected to be ready for

testing by 2017.

Though India had wanted the BrahMos to be based on a mid range

cruise missile like P-700 Granit, Russia opted for the shorter

range sister of the missile, P-800 Oniks, in order to comply

with Missile Technology Control Regime restrictions, to which

Russia is a signatory. Its propulsion is based on the Russian

missile, and missile guidance has been developed by BrahMos

Aerospace. The missile is expected to reach a total order

worth US$13 billion.

BrahMos has the capability of attacking surface targets by

flying as low as 5 meters in altitude and the maximum altitude it

can fly is 14000 meters. It has a diameter of 70 cm and a wing

span of 1.7 m. It can gain a speed of Mach 2.8, and has a maximum

range of 290 km. The ship-launched and land-based missiles can

carry a 200 kg warhead, whereas the aircraft-launched variant

(BrahMos A) can carry a 300 kg warhead. It has a two-stage

propulsion system, with a solid-propellant rocket for initial

acceleration and a liquid-fuelled ramjet responsible for

sustained supersonic cruise. Air-breathing ramjet propulsion is

much more fuel-efficient than rocket propulsion, giving the

BrahMos a longer range than a pure rocket-powered missile would

achieve. The high speed of the BrahMos likely gives it better

target-penetration characteristics than lighter subsonic cruise-

missiles such as the Tomahawk. Being twice as heavy and almost

four times faster than the Tomahawk, the BrahMos has more than 32

times the on-cruise kinetic energy of a Tomahawk missile,

although it carries only 3/5 the payload and a fraction of the

range despite weighing twice as much, which suggests that the

missile was designed with a different tactical role. Its 2.8 mach

speed means that it cannot be intercepted by some existing

missile defense system and its precision makes it lethal to water

targets. Although BrahMos was primarily an anti-ship missile, the

BrahMos Block III can also engage land based targets. It can be

launched either in a vertical or inclined position and is capable

of covering targets over a 360-degree horizon. The BrahMos

missile has an identical configuration for land, sea, and sub-sea

platforms. The air-launched version has a smaller booster and

additional tail fins for added stability during launch. The

BrahMos is currently being configured for aerial deployment with

the Su-30MKI as its carrier. On 5 September 2010 BrahMos created

a record for the first supersonic steep dive.