. DOCUMENT RESUME ED 111 621 SE 017 458 AUTHOR Mackin, T. E. TITLE Propulsion Systems for Aircraft. Aerospace Education II. INSTITUTION 'Air Univ., Maxwell AFB, Ala. Junior Reserve Office Training Corps.- PUB.DATE 73 NOTE 136p.; Colored drawings may not reproduce clearly. For the accompanying Instructor Handbook, see SE 017 459. This is a revised text for ED 068 292 EDRS PRICE, -MF-$0.76 HC.I$6.97 Plus' Postage DESCRIPTORS *Aerospace 'Education; *Aerospace Technology;'Aviation technology; Energy; *Engines; *Instructional-. Materials; *Physical. Sciences; Science Education: Secondary Education; Textbooks IDENTIFIERS *Air Force Junior ROTC ABSTRACT This is a revised text used for the Air Force ROTC _:_progralit._The main part of the book centers on the discussion -of the . engines in an airplane. After describing the terms and concepts of power, jets, and4rockets, the author describes reciprocating engines. The description of diesel engines helps to explain why theseare not used in airplanes. The discussion of the carburetor is followed byan explanation of the lubrication system. The chapter on reaction engines describes the operation of,jets, with examples of different types of jet engines.(PS) . 4,,!It********************************************************************* * Documents acquired by, ERIC include many informal unpublished * materials not available from other souxces. ERIC makes every effort * * to obtain the best copravailable. nevertheless, items of marginal * * reproducibility are often encountered and this affects the quality * * of the microfiche and hardcopy reproductions ERIC makes available * * via the ERIC Document" Reproduction Service (EDRS). EDRS is not * responsible for the quality of the original document. Reproductions * * supplied by EDRS are the best that can be made from the original. * ********************************************************************** U S OEPARTMENT OF HEALTH. EOUCATION &WELFARE NATIONAL INSTITUTE OF EOUCATION THIS DOCUMENT HAS BEEN REPRO DUCEO EXACTLY AS RECEivE0 FROM THE PERSON OR ORGANIZATION ORIGIN, *TING POINTS OF v.E.v OR OPINIONS STATED DO NOT NECESSARILY REPRE SENT OFFICIAL NATIONAL INSTITUTE OF EDUCATION POSITION OR POLICY 0 AEROSPACE EDUCATION II Propulsion Systemsfor Aircraft T. E. MACKIN Academic Publications Division 3825th Academic Services Group AIR FARCE JUNIOR ROTC MR UNIVERSITY MAXWELL AIR FORCE EASE, ALABAMA 3 1973 This publicatiod hos been reviewedand approved by competent personnel of the preparing command inaccordonce with current directives on doctrine, policy,essentiality, propriety, and quality. I This book will not be offered for sale. It isfor use only in the Air Force ROTC program. We gratefully acknowledge thecontribution of Lt CO Jomes D. Elmer, Chief, High School Curriculum Division,AFJROTC, to the development of this text. Preface ONE oF' MAN'S most persistent dreamsis to be able to fly through the air unencumbered, Likea bird. This was true hundreds of years ago, probablyeven back beyond the dawn of history. Evidence of thedream can be found in the fact that the gods of ancientcivilizations were endowed -V% with the power of flight. Men inthese early civilizations gave to their man-like gods abilities that simple,ordinary men. could not haveincluding the abilityto fly. The dream held true in later days also,as we can see from the many preserved drawings ofhuman beings before, during, and after the days of Leonardoda,Vinci. Even this a5 Italiangenius, whose abilitiesin many fields amaze sophisticated modernmen, thought, about, 'experimented with, and designed machinesto allow man to leave the ground..Da Vinci. and most other earlytheorists thought in terms of bird-like wings, operatedby the muscle power of the man wearing them. The dream exists even today,as we can see by the popu- larity of skydiving. This is thesport of parachutists who delight in jumping from planes,then soaring through the skies alone for as long as possible beforeopening their para- chutes. But accompanying this anciet. dreamhas always been a rude awakening to the fact thatman is just not built for flying. His body is*too heavyto be held aloft by his arms. His arms are arms, not wings. Andeven with wing -like devices to hold him up,man is just not strong enough to build up the force it takes to keep himself inthe air. Still, man does not concede that he is never to fly by himself, ill r- W1 out mechanicalassistance. (The skydiver isariexample of t grown men fly kites and envy the paper birdse put alOft. In his fantasies, man still dreams ofovercoming Int ground-bound d ign and soaring off by himself.After all, he reasons, thebumblebee defiet all the rules of aero- nautical design, ad still flies. So why not man? In the mean- time, however, mn has accepted a compromise:if he has not yet fOund aay to fly under his own power,he will do the next hesthinghe will use his machines for power. Only throuthe use of machines has man so far been able to even partially fulfill his dream ofcontrolled, con- tinuing flight. After countless centuries of gazing atthe sky and envying the birds, it is only withinthis century that man has made any real success of hisancient dream. It is the purpose of this volume to trace thedevelopment of the power machines that man uses topropel his flying machines through the air; to study thesePropulsion devices as they exist today; and tolook at developments that take man far beyond the rangeof the birds he envies. tp. Contents PREFACE Chapter 1----POWER IN FLIGHT Flight Theory 3 Internal Combustion Engines 5 Powered Flight 6 Gliders. 7 More Power 8 Success 8 Jets 10 Power Terms 11 Horsepower 12 Thrust '13' Thrust Horsepower 15 Chapter 2-- RECIPROCATING ENGINES 19 The Reciprocatidg Engine 20 The M&hadical System . ..... 20 Diesel Engines 25 Types of Reciprocating Engines 26 Performance of Reciprocating Engines 29 Heatand Cooling 30 Construction Matirials 32 Chapter 4-0THER ENGINE YSTEMS 37 --Fuels . ....... Volatility 39 Octane Rating 40. The Fuel System 42 Fuel Feeding... ... 42 , Carburetron 43 Carburetor Operation 45 Carburetor Accessories 48 Other Carburetor 'Types 52 Fuel Injection, Systems '54 Mass Air Flow System 55 Intake Metering, System 56 Advantages and Problems 57 Ignition System . 58 Magnetism and Electricity 58 The Magneto , 62 Starting Systems 68 The Lubrication System .... 69 Oil Properties 70 Oil Distribution , 71 Propellers- 73 Npmenclatiire . .:' 74 Motion . 75 Forces 76 Types 78, Reversing and Feathering 78 Limitations 80 Chapter 4Gas Turbines & Jet Proyulsion 85 Jet Engines 86 Principles of Operation 87 A ,. Ramjet . 88 Pulse Jet 90 The Turbojet 92 The Turboprop Engine 102 Turbofan Engine 105 Helicopter Engines 106 Some Important Systems 109 Accessory Section 109 Starting, the Engine 109 Fuel Systems 110 i Lubrication Systems. 111 Water Injection 111 Thrust Reversers, 112 Noise Suppression 115 Pollution 117 4 Comparisons . 118 SUMMARY: propulsion's Evolution 121 INDEX . 127 v18 -q":40rovInw#7 V Chapter1 11 IfA 116. Power in Flight err-NorGA NIA CHAPTER traces the higoriCal development, ofengines usedla power airtraft,H- give,b brief review-atcievelOpinents inair theory, lighter-than-air, crcift, ,Ond,glitier flight, always considering that suctessfUl powered flight IncOrpototed ad- vances in all of these areas. Uponarpletion-ef-thlechripter, you should ha able tot (1) exploin, the main ,differences betweeninternal- -rind external combustion onginOi,and the reasons external combustion ,engittes proved iMprottical for powering aircraft;. (2)1.11 why the interroatcombuttian engine ,waa io, long In developing and why it_ woe the 'key' ,to powered flight; (3).oxpia hitheten*"harsoPONYern- and "thrute: and-how 'they, are -related; and (4),compart-o,piston engine's power tolharof a jet intone. rilf!SUCCESSFULFLIGHTof powered aircraft had to a- it developments in several fields. The theory of flight, for instance, underwent many changes as man continued to experi- ment with kites And gliders, to study bird flight and the movement of sailing ships, and to thinkaboutthe nature of. air itself. We have seen in such Aerospace Education books. as The Aero- space Age (AEI) and Theory of Aircraft Flight (AEII) how man's concepts of flying devilopfd over the years. In this book PROPULSION SYSTEMS FOR AIRCRAFT 45. we look at the matter of flight from a different viewpoint: the development of the power plants that finally enabled the ancient dream to 'hecome reality. As an adjunct to the accumulation of knowledge came physical developments. One of the most significant developMents was the invention of the steam engine in the late eighteenth century. This new device represented man's first successful harnessing Of mech- anical power for useful work. It freed man from dependence on power from animals, wind, and falling water, and turned his thinking in new directions. The steam engine was a revolutionary invention, and is still in use to a'. As important as the steam engine was, it had a number of basic characteristics which made it unsuitable for aircraft power. For one thing, the steam engine was too bulky. For another, it wak not. responsive enough tothepilot'scontrol.It was too heavy. Moreover, it required external combustion. External combustion meant that the fire that heated the water and turned it into steam was located outside the engine itself. This feature., with its increased danger of fire, was more than just an inconvenience for someone who intended to fly through the air under power of a steam engine. (Some steam engines were used in