Technical English For Aerospace Engineering

PNU University

By: Dr. Reza Hosseini-Ara

Assistant professor of mechanical engineering Department of Mechanical Engineering

Payame Noor University

Technical English For Aerospace Engineering

1«.، که یک واجب دینی استملی یآموزی، نه تنها یک وظیفهخوانی و علمامروزه کتاب»

های ارزیابی رشد، توسعه و پیشرفت فرهنگی هر هدر عصر حاضر یکی از شاخصخوانی مردم آن مرز و بوم است. ایران کشوری میزان تولید کتاب، مطالعه و کتاب

با داشتن تمدنی چندهزارساله و مراکز متعدد علمی، تاکنوناسالمی نیز از دیرباز های معتبر، علما و دانشمندان بزرگ با آثار ارزشمند تاریخی، سرآمد فرهنگی، کتابخانه

سان خورشیدی هی فرهنگ و تمدن جهانی بهای دیگر بوده و در عرصهها و ملتدولتچه کسی .کندخویش هنرنمایی مینهاد درخشد و با فرزندان نیکتابناک همچنان می

آور ایرانی همچون ابوعلی سینا، ابوریحان فرزانه و نامکه در دنیا با دانشمندان است ،ای نظیر فردوسی، سعدیهمچنین شاعران برجستهبیرونی، فارابی، خوارزمی و ...

امی مولوی، حافظ و ... آشنا نباشد و در مقابل عظمت آنها سر تعظیم فرود نیاورد. تماین افتخارات ارزشمند، برگرفته از میزان عشق و عالقه فراوان ملت ما به فراگیری علم

،ی الهیهای گوناگون است. به شکرانهو مطالعه منابع و کتاب نو دانش از طریق خواندولی اکنون در این زمینه در چه .و پربار است درخشانتاریخ و گذشته ما، همیشه

های فرهنگی در شده از سوی مجامع و سازمانآمار و ارقام ارائهجایگاهی قرار داریم؟ .باشدی هر ایرانی، برایمان چندان امیدوارکننده نمیی مطالعهمورد سرانه

فت است و کتاب خوب، یکی ی دانش و معرای به سوی گسترهکتاب، دروازهی دستاوردهای بشر در سراسر عمر جهان، هاز بهترین ابزارهای کمال بشری است. هم

ها پدید هایی است که انساننوشتهدر میان دستتا آنجا که قابل کتابت بوده است، های پیامبران به بشر، و تعالیم الهی، درس ،نظیری بیآورند. در این مجموعهآورده و می

پذیر نیست. همچنین علوم مختلفی است که سعادت بشر بدون آگاهی از آنها امکانترین دستاورد از مهمشک بخش کتاب ارتباط ندارد بیو زندگی زیباکسی که با دنیای

روشنی ، بهانسانی و نیز از بیشترین معارف الهی و بشری محروم است. با این دیدگاهتوان ارزش و مفهوم رمزی عمیق در این حقیقت تاریخی را دریافت که اولین می

و در اولین «بخوان!«خطاب خداوند متعال به پیامبر گرامی اسالم)ص( این است که

4/11/27پیام مقام معظم رهبری به مناسبت آغاز هفته کتاب . 1

سه

به تجلیل یاد «قلم»الشأن خداوند، فرود آمده، نام ی عظیمای که بر آن فرستادهسورهوإ ق » است:شده در اهمیت عنصر کتاب برای تکامل «قلمبال رم.إلذیعلماک کإل رب رإ

ی انسانی، همین بس که تمامی ادیان آسمانی و رجال بزرگ تاریخ بشری، از جامعه اند.طریق کتاب جاودانه مانده

شمول خود با هدف آموزش برای جغرافیایی ایران ینور با گسترهپیام دانشگاهمحور در نظام آموزش عالی عنوان دانشگاهی کتاببه ،وقتجا و همههمه، همه

و خردورزی بخش عظیمی از جوانان سازی کشورمان، افتخار دارد جایگاه اندیشهجویای علم این مرز و بوم باشد. تالش فراوانی در ایام طوالنی فعالیت این دانشگاه

ظران برجسته نهای گرانقدر استادان و صاحبربهگیری از تجانجام پذیرفته تا با بهرهشاخص و خودآموز تولید شود. در آینده درسی ها و منابع آموزشی کشورمان، کتاب

این مهم با هدف ارتقای سطح علمی، روزآمدی و توجه بیشتر به نیازهای مخاطبان هم،طور قطع استفاده از نظرات استادان، نور با جدیت ادامه خواهد داشت. بهدانشگاه پیام

رسان ی مهم و خطیر یاریما را در انجام این وظیفه ،نظران و دانشجویان محترمصاحبهای خود ما را در دمی عزیزانی که با نقد، تصحیح و پیشنهاخواهد بود. پیشاپیش از تما

م. الزم است از تمامی ینمایرسانند، سپاسگزاری میی خطیر یاری میانجام این وظیفهو ما را در سازی خود دانسته نور را منزلگه اندیشهاندیشمندانی که تاکنون دانشگاه پیام

اند، صمیمانه قدردانی گردد. موفقیت هتولید کتاب و محتوای آموزشی درسی یاری نمودست.ا پژوهان عزیز آرزوی همیشگی ماو بهروزی تمامی دانشجویان و دانش

نوردانشگاه پیام

چهار

Table of Content Preface VI Chapter 1: An Introduction to Aerospace Engineering 1 Chapter 2: Aerodynamics 25 Chapter 3: Propulsion 45 Chapter 4: Aircraft engines 61 Chapter 5: Aircraft Structure 85 Chapter 6: Helicopter 105 Chapter 7: Glider 123 Chapter 8: Rockets 141 Chapter 9: Wind tunnel 167 Answers of vocabulary exercises 183 References 185

V

Preface Technical English for Aerospace Engineering is designed for undergraduate students of aerospace engineering whose first language is not English. It promotes the development of the reading, writing and understanding the different subjects of aerospace engineering.

This book is divided into nine chapters, namely: An Introduction

to Aerospace Engineering, Aerodynamics, Propulsion, Aircraft

engine, Aircraft structure, Helicopter, Glider, and Rockets, respectively.

Chapter 1 is about introduction, history, foundation and important elements of aerospace engineering. In chapter 2, fundamental concepts and practical objectives of aerodynamics are described. Chapter 3 presents propulsion in ground, marine and space applications. In chapter 4, different types of aircraft engines are presented. Also, in chapter 5, major airplane components are described in aircraft structure. Chapter 6 is about different features and performances of a helicopter. Chapter 7 describes different parts of a glider and technical points for its flight. In chapter 8, the history, technology, design, and operations of rockets are explained. Chapter 9 describes the wind tunnels for measurement of aerodynamic forces and flow visualization.

Each chapter in this book includes a technical text in the field of above mentioned subjects, new words, vocabulary exercises and descriptive questions. In the technical texts in each chapter, some new

VII VII

words are presented and underlined which are described in new words section at the end of the technical text. The vocabulary exercises are designed for the better understanding of these new words in each chapter. Finally, the descriptive questions are presented at the end of each chapter for increasing the reading and writing skills of students.

The author has attempted to take advantage of the latest aerospace engineering textbooks and sources as well as the most up to date ones. Kindly do send your feedback and comments for upgrading and improving the present book on my email address ([email protected]).

I want to thank my students over the years for many stimulating discussions on the subject of aerodynamics, which have influenced the development of this book.

Last but not least, this book would have been impossible without the patience and support of my beloved family.

Reza Hosseini-Ara

VIII

Chapter 1

An Introduction to Aerospace Engineering Introduction Aerospace engineering is the primary branch of engineering concerned with the research, design, development, construction, testing, science and technology of aircraft and spacecraft. The field also covers their aerodynamic characteristics and behaviors, airfoil, control surfaces, lift, drag, and other properties. It is divided into two major and overlapping branches: aeronautics and astronautics. Aeronautics deals with aircraft that operate in Earth’s atmosphere, and astronautics deals with spacecraft that operate outside the Earth’s atmosphere. (see figures 1.1 and 1.2)

Founded by pioneers such as Konstantin Tsiolkovsky, the field reached its maturity with launching of first artificial satellite, first man in space and first step on the Moon. In fact, aeronautical engineering was the original term for the field. As flight technology advanced to include craft operating in outer space, the broader term “aerospace engineering” has largely replaced it in common usage. Aerospace engineering, particularly the astronautics branch, is often referred to colloquially as “rocket science”, such as in popular culture.

2 Technical English For Aerospace Engineering

Figure 1.1. Parts of an aircraft

Figure 1.2. Parts of a sample spacecraft

An Introduction to Aerospace Engineering 3

1.1. Overview Flight vehicles are subjected to demanding conditions such as those produced by changes in atmospheric pressure and temperature, with structural loads applied upon vehicle components. Consequently, they are usually the products of various technological and engineering disciplines including aerodynamics, propulsion, avionics, materials science, structural analysis and manufacturing. The interaction between these technologies is known as aerospace engineering. Because of the complexity and number of disciplines involved, aerospace engineering is carried out by teams of engineers, each having their own specialized area of expertise.

The development and manufacturing of a modern flight vehicle is an extremely complex process and demands careful balance and compromise between abilities, design, available technology and costs. Indeed, aerospace engineers design, test, and supervise the manufacture of aircraft, spacecraft, and missiles. Moreover, aerospace engineers develop new technologies for use in aviation, defense systems, and space. (see figure 1.3)

Figure 1.3. A sample of modern aircraft cockpit (G600 avionics install)


1.2. History The origin of aerospace engineering can be traced back to the aviation pioneers around the late 19th to early 20th centuries, although the work of Sir George Cayley dates from the last decade of the 18th to mid-19th century. One of the most important people in the history of aeronautics, Cayley was a pioneer in aeronautical engineering and is credited as the first person to separate the forces of lift and drag, which are in effect on any flight vehicle. Early knowledge of aeronautical engineering was largely empirical with some concepts and skills imported from other branches of engineering. Scientists understood some key elements of aerospace engineering, like fluid dynamics, in the 18th century. Many years later after the successful flights by the Wright brothers, the 1910s saw the development of aeronautical engineering through the design of World War (I) military aircraft.

In fact, attempts to fly without any real aeronautical understanding have been made from the earliest times, typically by constructing wings and jumping from a tower with crippling or lethal results. Man-carrying kites are believed to have been used extensively in ancient China. In 1282 the European explorer Marco Polo described the Chinese techniques then current. The Chinese also constructed small hot air balloons, or lanterns, and rotary-wing toys.

An early European to provide any scientific discussion of flight was Roger Bacon, who described principles of operation for the lighter-than-air balloon and the flapping-wing ornithopter, which he envisaged would be constructed in the future. The lifting medium for his balloon would be an “aether” whose composition he did not know.

Meanwhile, wiser investigators sought to gain some rational understanding through the study of bird flight. An early example appears in ancient Egyptian texts. Later medieval Islamic scientists also made such studies. The founders of modern aeronautics, Leonardo da Vinci in the Renaissance and Cayley around 1800, both began their investigations with studies of bird flight. In the late fifteenth century, Leonardo da Vinci followed up his study of birds with designs for some


of the earliest flying machines, including the flapping-wing ornithopter and the rotating-wing helicopter. (see figure 1.4)

Although his designs were rational, they were not based on particularly good science. Many of his designs, such as a four-person screw-type helicopter, have severe flaws. He did at least understand that “An object offers as much resistance to the air as the air does to the object.” (Newton would not publish the Third law of motion until 1687) His analysis led to the realization that manpower alone was not sufficient for sustained flight, and his later designs included a mechanical power source such as a spring. Da Vinci’s work was lost after his death and did not reappear until it had been overtaken by the work of George Cayley.

Figure 1.4. Designs for flying machines by Leonardo da Vinci, circa 1490

https://en.wikipedia.org/wiki/File:Leonardo_da_Vinci_helicopter_and_lifting_wing.jpg


1.3. Foundation of modern aeronautics Sir George Cayley (1773-1857) is widely acknowledged as the founder of modern aeronautics. He was first called the “father of the airplane” in 1846 and Henson called him the “father of aerial navigation.” He was the first true scientific aerial investigator to publish his work, which included the underlying principles and forces of flight for the first time (figure 1.5).

Figure 1.5. Sir George Cayley (1773-1857) In 1809 he began the publication of a landmark three-part treatise

titled “On Aerial Navigation” (1809–1810). He wrote the first scientific statement of the problem, “The whole problem is confined within these limits, to make a surface support a given weight by the application of power to the resistance of air.” He identified the four vector forces that influence an aircraft: thrust, lift, drag and weight and distinguished stability and control in his designs. He developed the modern conventional form of the fixed-wing airplane having a stabilizing tail with both horizontal and vertical surfaces, flying gliders both unmanned and manned (figure 1.6).

Moreover, he introduced the use of the whirling arm test rig to investigate the aerodynamics of flight, using it to discover the benefits of the curved or cambered airfoil over the flat wing he had used for his first glider. He also identified and described the importance of dihedral, diagonal bracing and drag reduction, and contributed to the


understanding and design of ornithopters and parachutes. Another significant invention was the tension-spoked wheel, which he devised in order to create a light, strong wheel for aircraft undercarriage.

Figure 1.6. Cayley’s glider in Mechanics Magazine (1852)

1.4. Elements of aerospace engineering Some of the elements of aerospace engineering are as follows: Mathematics: in particular, calculus, differential equations, and

linear algebra. Statics and Dynamics: the study of movement, forces, moments in

mechanical systems.


Fluid mechanics: the study of fluid flow around objects. Specifically aerodynamics concerning the flow of air over bodies such as wings or through objects such as wind tunnels.

Astrodynamics: the study of orbital mechanics including prediction of orbital elements when given a select few variables.

Electro-technology: the study of electronics within engineering. Propulsion: the energy to move a vehicle through the air or in outer

space is provided by internal combustion engines, jet engines and turbo machinery, or rockets. A more recent addition to this module is electric propulsion and ion propulsion.

Control engineering: the study of mathematical modeling of the dynamic behavior of systems and designing them, usually using feedback signals, so that their dynamic behavior is desirable (stable, without large excursions, with minimum error). This applies to the dynamic behavior of aircraft, spacecraft, propulsion systems, and subsystems that exist on aerospace vehicles.

Aircraft structures: design of the physical configuration of the craft to withstand the forces encountered during flight. Aerospace engineering aims to keep structures lightweight.

Materials science: related to structures, aerospace engineering also studies the materials of which the aerospace structures are to be built. New materials with very specific properties are invented, or existing ones are modified to improve their performance.

Solid mechanics: closely related to material science is solid mechanics which deals with stress and strain analysis of the components of the vehicle. Nowadays there are several Finite Element programs which aid engineers in the analytical process.

Aero elasticity: the interaction of aerodynamic forces and structural flexibility, potentially causing flutter, divergence, etc.

Avionics: the design and programming of computer systems on board an aircraft or spacecraft and the simulation of systems.

Software: the specification, design, development, test, and implementation of computer software for aerospace applications,


including flight software, ground control software, test and evaluation software, etc.

Risk and reliability: the study of risk and reliability assessment techniques and the mathematics involved in the quantitative methods.

Noise control: the study of the mechanics of sound transfer. Aero acoustics: the study of noise generation via either turbulent

fluid motion or aerodynamic forces interacting with surfaces. Flight test: designing and executing flight test programs in order to

gather and analyze performance and handling data in order to determine if an aircraft meets its design and performance goals and certification requirements.

The basis of most of these elements lies in theoretical physics, such as fluid dynamics for aerodynamics or the equations of motion for flight dynamics. There is also a large empirical component. Historically, this empirical component was derived from testing of scale models and prototypes, either in wind tunnels or in the free atmosphere. More recently, advances in computing have enabled the use of “Computational Fluid Dynamics” or CFD to simulate the behavior of fluid, reducing time and expense spent on wind-tunnel testing.

Additionally, aerospace engineering addresses the integration of all components that constitute an aerospace vehicle and its life cycle. In fact, aeronautics (from the ancient Greek, which means “navigation of the air”) is the science or art involved with the study, design, and manufacturing of air flight capable machines, and the techniques of operating aircraft and rockets within the atmosphere. The British Royal Aeronautical Society identifies the aspects of “aeronautical art, science and engineering” and “the profession of aeronautics” (which expression includes astronautics). While the term, literally meaning “sailing the air”, originally referred solely to the science of operating the aircraft, it has since been expanded to include technology, business and other aspects related to aircraft. The term “aviation” is sometimes, used interchangeably with aeronautics, although “aeronautics”


includes lighter-than-air craft such as airships, and includes ballistic vehicles while “aviation” technically does not. A significant part of aeronautical science is a branch of dynamics called aerodynamics, which deals with the motion of air and the way that it interacts with objects in motion, such as an aircraft. 1.5. New words (A) Additionally: as an extra factor or circumstance Aerial: existing, happening, or operating in the air Aeronautics: the science or practice of travel through the air Aether: (a variant spelling of ether); the element believed in ancient and medieval civilizations to fill all space above the sphere of the moon and to compose the stars and planets Aim: the action of directing something at an object Aid: help; assist Allow: let someone have or do something Altitude: the height of an object or point in relation to sea level or ground level Artificial: made or produced by human beings rather than occurring naturally, typically as a copy of something natural Ascent: climb or walk to the summit of a mountain or hill; rise Assessment: evaluation Astronautics: the science and technology of human space travel and exploration Atmospheric pressure: the pressure exerted by the weight of the atmosphere Aviation: the flying or operating of aircraft Avionics: electronics as applied to aviation Await: to wait for (an event)


(B) Ballast: heavy material, such as gravel, sand, iron, or lead, placed low in a vessel to improve its stability Ballistic: relating to projectiles or their flight Ballonet: a separate gas- or air-filled compartment within the main envelope of a balloon or airship, designed for the maintenance or adjustment of the envelope’s shape, buoyancy, or orientation Balloon: small colored rubber bag which is inflated with air and then sealed at the neck, used as a child’s toy or a decoration Bracing: support Branch: an area of specialized skill or knowledge Broad: wide (C) Calculus: The branch of mathematics that deals with the finding and properties of derivatives and integrals of functions, by methods originally based on the summation of infinite estimable differences Cambered: the slightly convex or arched shape of a road or other horizontal surface

Catch: take; capture Certification: an official document attesting to a status or level of achievement Closely: nearly Collapse: suddenly fall down (for a structure) Colloquially: conversationally; informally Compromise: an agreement or a settlement of a dispute that is reached by each side making concessions Composition: the nature of something’s ingredients or constituents Concept: an abstract idea; a general notion Concerned: worried; involved in something Configuration: An arrangement of parts or elements in a particular form, figure, or combination Confined: restricted in area or volume; limited


Consequently: as a result Constant: unchangeable Constitute: be a part of a whole Construction: structure Container: an object for holding or transporting something Conventional: based on or in accordance with what is generally done or believed; customary Credible: able to be believed; valid Credit: publicly acknowledge someone as a participant in the production of (something published or broadcast) Crippling: Cause someone to become unable to walk or move properly (D) Demand: an insistent request, order or command Demonstration: an act of showing that something exists or is true by giving proof or evidence Desirable: favorable; eligible Determine: fix or define the position, form, or configuration of something Devise: plan or invent (a complex procedure, system, or mechanism) by careful thought Dew: tiny drops of water that form on cool surfaces at night, when atmospheric vapor condenses Diagonal: (of a straight line) joining two opposite corners of a square, rectangle, or other straight-sided shape Differential equations: an equation involving derivatives of functions Dihedral: an angle formed by two plane faces Dirigible: able to be steered or directed Discipline: the practice of training people to obey rules or a code of behavior, using punishment to correct disobedience Distinguished: eminent; outstanding


Divergence: one kind of dynamic instability of an elastic structure in a fluid flow Drag: the resistance to the motion of a body passing through a fluid, especially through air Drop: let or make something fall vertically (E) Elongate: make something longer, especially unusually so in relation to its width Empirical: based on observation or experience rather than theory or pure logic, experimental Encounter: unexpectedly be faced with or experience something; confront; face Endurance: tolerance Envisaged: contemplate, imagine Era: a period of time considered as being of a distinctive character; epoch Evaluation: the making of a judgment about the amount, number, or value of something; assessment Excursion: a short journey or trip, especially one taken as a leisure activity Execute: carry out Expertise: expert skill or knowledge in a particular field Exploit: make full use of and derive benefit from a resource Extremely: a very great degree (F) Fantasy: the activity of imagining impossible or improbable things Feedback signals: the portion of the output so returned Flapping: moving up and down when flying or preparing to fly Flaw: a fault, or imperfection Fluid dynamics: the science of investigating the dynamics of fluids Flutter: a potentially dangerous oscillation of an aircraft, or part of an


aircraft, caused by the interaction of aerodynamic forces, structural elastic reactions, and inertia Found: establish or originate (an institution or organization) Founder: organizer, establisher (G) Gain: acquire; achieve Gas-tight: sealed so as to prevent the leakage of gas Gather: come together; collect Generation: belonging to a specified stage of development in manufacture, usually implying improvement Ground: the solid surface of the earth (H) Hanging: suspended in the air (I) Identify: indicate who or what someone or something is; recognize Implementation: the process of putting a decision or plan into effect; execution Indeed: in fact Integration: the act of combining or adding parts to make a unified whole Interact: interface; act reciprocally Interchangeably: in a way that can be exchanged Internal combustion engine: an engine which generates motive power by the burning of petrol, oil, or other fuel with air inside the engine, the hot gases produced being used to drive a piston or do other work as they expand Invent: create or design (something that has not existed before); be the originator of Investigator: a person who carries out a formal inquiry or investigation

Technical English For Aerospace Engineering

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