Fundamentals of Aircraft and Rocket Propulsion.pdf

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Ahmed F. El-Sayed

Fundamentals of Aircraft

and Rocket

Propulsion

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Fundamentals of Aircraft

and Rocket Propulsion

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Department of Mechanical Engineering Zagazig University

Zagazig, Egypt

ISBN 978-1-4471-6794-5 ISBN 978-1-4471-6796-9 (eBook) DOI 10.1007/978-1-4471-6796-9

Library of Congress Control Number: 2016940096

©Springer-Verlag London 2016

The author(s) has/have asserted their right(s) to be identified as the author(s) of this work in accordance with the Copyright, Design and Patents Act 1988.

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The publisher, the authors and the editors are safe to assume that the advice and information in this book are believed to be true and accurate at the date of publication. Neither the publisher nor the authors or the editors give a warranty, express or implied, with respect to the material contained herein or for any errors or omissions that may have been made.

Printed on acid-free paper

This Springer imprint is published by Springer Nature The registered company is Springer-Verlag London Ltd.

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and encouragement were a constant source

for my inspiration

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Pedagogically, the fundamental principles are the foundation for lifelong learning.

Thus, this book through a simple treatment can provide students of aerospace/

aeronautical and mechanical engineering with a deep understanding of both aircraft and spacecraft propulsions. The development of aircrafts in only one century is far beyond expectations.

December 1903 was the dawn of human-engineered flight when the Wright Brothers flew their first flights that lasted for a few seconds in Ohio, USA. This first aircraft was powered by a single piston engine and had no passengers, neither did it have a fuselage nor landing gears. It is extremely amazing that in 2011 over 2.8 billion passengers were carried by the world’s commercial airlines via more than 222,500 aircrafts powered by more than 260,000 different types of aero engines. Some of these aircrafts can carry as many as 800 passengers for more than 15 h of flying time, while others can fly at supersonic speeds. In 2015, the number of passengers exceeded 3.3 billion. Now, piston engines are no longer the single actor in propulsion theater, though they are still dominant! Turbojet engines were the first jet engines invented in the late 1930s and took a reasonable share in military and civil-powered flights for nearly two decades. In the late 1950s and early 1960s, turbofan engines (or bypass turbojet engines) were invented. These are the present prevailing engines which power faster, quieter, cleaner, and heavier aircrafts. In the 1950s also two other engine types, namely, turboprop and turboshaft, were invented to power commercial airliners and military transport aircrafts and rotorcrafts.

Due to the rapid advance in air transportation as well as military and intelligence missions, aircraft and rocket propulsion has become an essential part of engineering education. Propulsion is the combined aero-thermal science for aircrafts and rockets. Propulsion has both macro- and microscales. Macroscale handles the performance and operation of aircrafts and rockets during different missions, while microscale is concerned with component design including both rotary modules (i.e., compressor, fan, pump, and turbine) and stationary modules (i.e., intake, combustor, afterburner, and nozzle).

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The primary aim of this text is to give students a thorough grounding in both the theory and practice of propulsion. It discusses the design, operation, installation and several inspections, repair, and maintenance aspects of aircraft and rocket engines.

This book serves as a text for undergraduate and first year graduate students in mechanical, aeronautical, aerospace, avionics, and aviation engineering depart- ments. Moreover, it can be used by practicing engineers in aviation and gas turbine industries. Background in fluid mechanics and thermodynamics at fundamental levels is assumed. The book also provides educators with comprehensive solved examples, practical engine case studies, intelligent unsolved problems, and design projects. The material of this book is the outcome of industrial, research, and educational experience for more than 40 years in numerous civil, military institu- tions, and companies of 9 countries including the USA, Russia, Austria, UK, Belgium, China, and Japan as well as Egypt.

The book is composed of 11 chapters and 4 appendices. The first ten chapters handle air-breathing engines, while non-air-breathing (or rocket) engines are analyzed in Chap.11.

Chapter1is rather a unique one! It provides a rigorous classification of all types of aircrafts and its sources of power. The first part classifies aircrafts as aerostats/

aerodynes, fixed wing/rotary wing (or rotorcrafts), and hybrid fixed/rotary wings as well as all other lift aircrafts (flapping wing or ornithopter, lifting body, and fan wing). The second part handles power plant types. Power plants belong to two main groups, namely, external and internal combustion engines. External combustion engines are steam, Stirling, and nuclear engines. Internal combustion engines are further classified as shaft and reaction engines. Shaft engine group is either of the intermittent combustion types (Wankel and piston) or continuous combustion types (turboprop, turboshaft, and propfan). Reaction engines are either of the athodyd or turbine engines. Athodyd engines include ramjet, scramjet, and pulsejet (valved, valveless, and pulse detonation types). Finally, turbine-based engines include turbojet, turbofan, and turbo-ramjet engines.

Chapters2and3emphasize that a few fundamental physical principles, rightly applied, can provide a deep understanding of operation and performance of aircrafts and space vehicles.

Chapter2provides a review of basic laws of compressible flow with heat and friction. Conservation of mass, momentum, moment of momentum, and energy equations applied to open control volume are reviewed. A review for aspects of normal and oblique shock waves and Fanno and Rayleigh flows follows. Flow in diffusers in aircrafts as well as flow in nozzles in both aircrafts and rockets are discussed. Standard atmosphere is highlighted to emphasize variations of air prop- erties at different altitudes.

Chapter3relies upon governing formulae reviewed in Chap.2 in driving the different performance parameters of jet propulsion, namely, thrust force, operation efficiencies (propulsive, thermal, and overall), specific impulse, and fuel consumption. Other parameters that couple aircraft and engine performance like aircraft

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range and endurance are presented. Analysis of aircraft mission, route planning, and non-return point are next highlighted.

Chapter 4 provides the necessary analyses of piston engines and propellers.

Though piston engine was the first in-flight air-breathing engine employed by the Wright brothers in 1903, it maintains its strong existence until now. It represents more than 70 % of present-day air-breathing engines. They are extensively used in small fixed wing, sport aircrafts, UAVs, and lighter than air flying vehicles, as well as many rotorcrafts. Unfortunately, it is overlooked in most available propulsion books. A concise analysis of power cycles for two- and four-stroke engines, compression or spark ignition (CI and SI), and Wankel engines as well as turbo- and superchargers is reviewed for power and thermal efficiency optimization.

Piston engines cannot generate the necessary propulsive force for a flying vehicle on its own. Thus, it should be coupled to propellers. Classifications of propellers based on various aspects are defined. Propeller’s power and thrust force coefficients are defined using simple aerodynamic theories (momentum, modified momentum, and blade-element).

Chapter 5 is devoted to athodyd (nonrotating modules) engines, namely, pulsejet, ramjet, and scramjet engines. All cannot produce thrust force at zero flight speed, so other propulsive methods are used for takeoff operation. Each engine is composed of intake, combustion chamber, and nozzle. An analysis of ideal and real cycles as well as performance parameters of all engines is identified. Pulsejet engine is an internal combustion engine that produces thrust intermittently and is either of the valved or valveless type. Pulse detonation engine (PDE) is evolved in the last decade. PDE promises higher fuel efficiency (even compared withturbofan jet engines). Ramjet engine represents the first invented continuous combustion engine. It is used in both aircrafts and rockets. The third engine analyzed in this chapter is scramjet (supersonic combustion ramjet). Combustion takes place in supersonicairflow. Thus it can fly at extremely high speeds (NASA X-43Areached Mach 9.6). Finally, dual-mode (Ram-Scram) combustion engine is analyzed.

Chapters 6 and 7 treat air-breathing engines incorporating rotating modules.

Chapter 6 handles turbine-based engines (turbojet, turbofan, and turbo-ramjet), while Chap. 7 treats shaft-based engines (turboprop, turboshaft, and propfan).

One of the objectives of both chapters is to exercise students to practice realistic engines, build confidence, and a sense of professionalism. Both chapters start with a historical prospective and a classification of each engine. Next, thermodynamic and performance analyses for ideal and real cycles are introduced and further explained via solved examples. Chapter6starts by the first flown jet engine, namely, turbojet engine, which was coinvented in the 1930s by British and German activities.

Analyses of single and double spools in the presence and absence of afterburner are described. Though rarely used in airliners or military planes in present days, it is still used in micro turbojets and turbojets powering rockets during sustained flight.

Turbofan engines are continuing its superiority for most present commercial airliners and military planes as well as some rockets for sustained flight. A unique classification of the numerous types of this engine based on fan location

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(forward/aft), bypass ratio (low/high), number of spools (single/double/triple), number of nozzles (single/double), fan/turbine coupling (geared/ungeared), and finally afterburner (present/absent) is given. After detailed analyses for some (not all) types of turbofan, the third engine, namely, turbo-ramjet, is presented. It is found in two configurations: wraparound or above/under types. An analysis of its single mode or combined mode is precisely defined.

Chapter7is confined to shaft-based engines in which performance is controlled by shaft power rather than thrust force. Also, its economy is governed by brake- specific fuel consumption rather than thrust-specific fuel consumption. Turboprop engines power manned and unmanned aircrafts. It may be of the puller (tractor) or pusher types. It may be also either a single or double spool. This section is ended by an analogy between turboprop and turbofan engines. Next, turboshaft engines which mainly power helicopters are classified and analyzed. Exhaust speeds are no longer important in this type of engines as all available energy is converted into shaft power. Finally, propfan or unducted fan (UDF) engines, normally described as ultrahigh bypass (UHP) ratio engine, are classified based on fan location (forward/

aft) and numbers of fan stages (single/double). A thermodynamic analysis of this engine is presented for the first time in this book. It combines features from both turbofan and turboprop engines.

Chapter8 presents aero-/thermodynamic analyses of stationary modules of jet engines, namely, intakes, combustion chamber, afterburner, and nozzle. At first, different methods for power plant installation (wing/fuselage/tail, or combinations) are discussed as it has a direct influence on air flow rates into intakes and ingestion of foreign objects into the engines. Also, intakes for fixed and rotary wing aircrafts as well as rockets are described. Moreover, subsonic and supersonic intakes are reviewed for optimum jet engine performance. Intake geometry and its performance are also presented. A review of combustion chambers including types, chemistry of combustion, aerodynamics, and thermodynamics of flow in its different elements is presented. Afterburners in turbojets/turbofans in supersonic aircrafts are analyzed. Different types of aviation fuels and biofuels as a future jet fuel for green aviation are examined. The exhaust system is treated here in a general scope.

Convergent and convergent divergent (de Laval) nozzles are analyzed. Moreover, thrust reverse and thrust vectoring are reviewed. Noise control for nozzles is given.

Turbomachinery (i.e., fans, compressors, and turbines) are treated in Chaps.9 and10. The objective of both chapters is to provide a simplified understanding of its aerodynamics, thermal, and stresses in both compressors and turbines. In Chap.9, different types of compressors are first identified, but only centrifugal and axial flow types are analyzed. The three main components of centrifugal compressor, namely, impeller, stator, and volute/scroll, are first analyzed taking into consideration their different types. Positive/negative prewhirl is also presented. Concerning axial compressor, the aerodynamics of single and multistages is reviewed. A performance map for both compressors is employed in identifying design and off-design operation. Lastly, different mechanisms for avoiding surge and rotating stall are discussed.

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Chapter10treats radial and axial flow turbines. Radial turbine is to a great extent similar to centrifugal compressor. The aerodynamics and thermodynamics of its components (i.e., inlet, nozzle, rotor, and outlet duct) are presented. Next, single and multistage axial flow turbines are treated with either impulse or reaction blading. Mechanical design and cooling techniques are reviewed. Finally, turbine map and off-design performance of both turbines are discussed. Matching between compressors and turbines in both gas generators and jet engines ends this chapter.

Rocket propulsion is discussed in Chap. 11. It starts with a brief history of rocketry followed by classifications of rockets based on type, launching mode, range, engine, warhead, and guidance systems. Rocket performance parameters (i.e., thrust force, effective exhaust velocity, specific impulse, thrust coefficient, and combustion chamber pressure drop) are derived in closed forms similar to those in Chap. 3 for air-breathing engines. A comprehensive section for multistaging is presented. Finally, an analysis of exhaust system (i.e., nozzle geometry, exhaust velocity, and structural coefficient) is given. Both chemical and nonchemical rocket engines are reviewed. Chemical rockets are further divided into liquid, solid, and hybrid rockets. Solid propellant types, combustion chamber, and nozzles are defined. In liquid propellant rockets, a turbopump is added. A hybrid rocket combines liquid and solid propellant systems. Nonchemical rockets including nuclear heating and electrically powered and electrothermal, electromagnetic, and electrostatic thrusters are reviewed.

The book ends with 4 appendices. These lists chronicle details of piston, turbojet, and turbofan engines, as well as milestones for rockets.

Finally, I would like to express my sincere appreciation and gratitude to Airbus Industries and Rolls-Royce plc for their permission to use illustrations and photo- graphs within this text.

I would like to express my sincere thanks to my editor, Charlotte Cross, who was a great help since day one and continued her support during the tough time of manuscript writing.

I’m deeply honored by the support of the dean and staff of Moscow Institute for Physics and Technology (MIPT), Moscow University, and for granting me their medal of 50th anniversary

Particular thanks for the continuous help and technical support of:

• Professor Darrell Pepper, Director, NCACM, University of Nevada Las Vegas, USA

• Mr. Joseph Veres, Compressor Section, NASA Glenn Research Center, Cleve- land, USA

• Professor Louis Chow, University of Central Florida, Orlando, USA

• Dr. Dennis Barbeau, AIAA Phoenix Section, USA

I would like to express my sincere thanks and utmost gratitude to my students:

Ahmed Z. Almeldein,Aerospace Department, Korea Advanced Institute of Science and Technology, South Korea; Mohamed Aziz and Eslam Said Ahmed, Institute of Aviation Engineering and Technology (IAET); Amr Kamel, Egyptian Air Force;

Mohamed Emera and Ibrahim Roufael, Mechanical Power Engineering

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Department, Zagazig University; and Ahmed Hamed, Senior Production Engineer, Engine Overhaul Directorate, EgyptAir Maintenance and Engineering Company.

At last, I extend my heartfelt gratitude to my wife, Amany, and sons Mohamed, Abdallah, and Khalid who were the real inspiration and motivation behind this work.

Zagazig, Egypt Ahmed F. El-Sayed

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1 Classifications of Aircrafts and Propulsion Systems. . . 1

1.1 Introduction . . . 1

1.2 Classifications of Aircrafts . . . 3

1.2.1 General . . . 3

1.2.2 Aerostats . . . 3

1.2.3 Aerodynes . . . 4

1.2.4 Fixed Wing Aircrafts . . . 5

1.2.5 Rotorcrafts (Rotor-Wing Aircrafts) . . . 31

1.2.6 Hybrid Fixed/Rotary Wings . . . 44

1.2.7 Other Methods of Lift Aircrafts . . . 47

1.3 Classifications of Propulsion Systems . . . 51

1.3.1 External Combustion . . . 51

1.3.2 Internal Combustion . . . 55

1.3.3 Other Power Sources . . . 78

References . . . 89

2 A Review of Basic Laws for a Compressible Flow. . . 91

2.2 System and Control Volume . . . 92

2.3 Fundamental Equations . . . 92

2.3.1 Conservation of Mass (Continuity Equation) . . . 94

2.3.2 Linear Momentum (Newton’s Second Law) . . . 96

2.3.3 Angular Momentum Equation (Moment of Momentum) . . . 103

2.3.4 Energy Equation (First Law of Thermodynamics) . . . 106

2.3.5 The Second Law of Thermodynamics and the Entropy Equation . . . 110

2.3.6 Equation of State . . . 111

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2.4 Steady One-Dimensional Compressible Flow . . . 114

2.4.1 Isentropic Relations . . . 114

2.4.2 Sonic Conditions . . . 116

2.4.3 Classification of Mach Regimes . . . 119

2.4.4 Diffusers and Nozzles . . . 120

2.4.5 Shocks . . . 125

2.5 Rayleigh Flow Equations . . . 146

2.6 The Standard Atmosphere . . . 151

References . . . 160

3 Performance Parameters of Jet Engines. . . 161

3.2 Thrust Force . . . 162

3.3 Factors Affecting Thrust . . . 174

3.3.1 Jet Nozzle . . . 175

3.3.2 Air Speed . . . 175

3.3.3 Mass Air Flow . . . 175

3.3.4 Altitude . . . 176

3.3.5 Ram Effect . . . 177

3.4 Engine Performance Parameters . . . 178

3.4.1 Propulsive Efficiency . . . 179

3.4.2 Thermal Efficiency . . . 186

3.4.3 Propeller Efficiency . . . 189

3.4.4 Overall Efficiency . . . 189

3.4.5 Takeoff Thrust . . . 192

3.4.6 Specific Fuel Consumption . . . 193

3.4.7 Aircraft Range . . . 200

3.4.8 Range Factor . . . 205

3.4.9 Endurance and Endurance Factor . . . 205

3.4.10 Mission Segment Weight Fraction . . . 206

3.4.11 Head- and Tail-Wind . . . 206

3.4.12 Route Planning . . . 209

3.4.13 Specific Impulse . . . 213

4 Piston Engines and Propellers. . . 219

4.2 Intermittent (or Piston) Engines . . . 221

4.2.1 Milestones . . . 223

4.2.2 Types of Aero Piston Engines . . . 223

4.3 Aerodynamics and Thermodynamics of Reciprocating ICE . . . 232

4.3.1 Terminology for Four-Stroke Engine . . . 232

4.3.2 Air-Standard Analysis . . . 233

4.3.3 Engine Cycles . . . 235

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4.4 Aircraft Propellers . . . 261

4.4.1 Introduction . . . 261

4.4.2 Nomenclature . . . 264

4.5 Classifications . . . 265

4.5.1 Source of Power . . . 265

4.5.2 Material . . . 265

4.5.3 Coupling to the Output Shaft . . . 267

4.5.4 Control . . . 267

4.5.5 Number of Propellers Coupled to Each Engine . . . . 269

4.5.6 Direction of Rotation . . . 269

4.5.7 Propulsion Method . . . 271

4.5.8 Number of Blades . . . 271

4.6 Aerodynamic Design . . . 273

4.6.1 Axial Momentum, (or Actuator Disk) Theory . . . 274

4.6.2 Modified Momentum or Simple Vortex Model . . . 281

4.6.3 Blade Element Considerations . . . 282

4.7 Dimensionless Parameters . . . 287

4.8 Typical Propeller Performance . . . 293

4.9 Conclusion . . . 304

5 Pulsejet, Ramjet, and Scramjet Engines. . . 315

5.1 Introduction to Athodyd Engines . . . 315

5.2 Pulsejet . . . 315

5.2.2 Brief History . . . 316

5.2.3 Valved Pulsejet . . . 318

5.2.4 Thermodynamic Cycle . . . 319

5.2.5 Valveless Pulsejet . . . 327

5.2.6 Pulsating Nature of Flow Parameters in Pulsejet Engines . . . 329

5.2.7 Pulse Detonation Engine (PDE) . . . 330

5.3 Ramjet . . . 337

5.3.2 Applications . . . 338

5.3.3 Aero-Thermodynamic Analysis of Modules . . . 341

5.3.4 Aero-thermodynamic Analysis of Ramjet Cycle . . . 348

5.3.5 Nuclear Ramjet . . . 360

5.3.6 Double Throat Ramjet Engine . . . 362

5.4 Scramjet . . . 364

5.4.2 Evolution of Scramjets . . . 365

5.4.3 Advantages and Disadvantages of Scramjets . . . 367

5.4.4 Aero-Thermodynamic Analysis of Scramjets . . . 367

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5.4.5 Performance Analysis . . . 371

5.4.6 Dual-Mode Combustion Engine (Dual Ram-Scramjet) . . . 376

6 Turbine-Based Engines: Turbojet, Turbofan, and Turboramjet Engines. . . 403

6.2 Turbojet . . . 404

6.2.2 Milestones of Turbojet Engines . . . 407

6.2.3 Thermodynamic Cycle Analysis of a Single Spool . . . 407

6.2.4 Performance Parameters of a Single Spool . . . 416

6.2.5 Important Definitions . . . 417

6.2.6 Double-Spool Turbojet . . . 430

6.2.7 Thermodynamic Analysis of Double-Spool Turbojet . . . 430

6.2.8 Performance Parameters of Double-Spool Turbojet Engine . . . 435

6.2.9 Micro-turbojet . . . 441

6.3 Turbofan . . . 445

6.3.2 Milestones . . . 446

6.3.3 Classifications of Turbofan Engines . . . 446

6.3.4 Forward Fan Unmixed Double-Spool Configuration . . . 448

6.3.5 Forward Fan Mixed-Flow Engine . . . 461

6.3.6 Forward Fan Unmixed Three-Spool Engine . . . 471

6.4 Turbine-Based Combined-Cycle (TBCC) Engines . . . 479

6.4.2 Historical Review of Supersonic and Hypersonic Aircrafts . . . 481

6.4.3 Technology Challenges of the Future Flight . . . 486

6.4.4 Propulsion System Configurations . . . 486

6.4.5 Performance of TBCC (or Hybrid Engine) . . . 490

6.4.6 Cycle Analysis of Turboramjet (or TBCC) Engine . . . 492

6.4.7 General Analysis for a Turboramjet Engine . . . 498

6.4.8 Design Procedure . . . 508

6.4.9 Future TBCC Engine . . . 509

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7 Shaft Engines Turboprop, Turboshaft, and Propfan. . . 531

7.2 Turboprop Engines . . . 532

7.2.2 Milestones . . . 534

7.2.3 Thermodynamics Analysis of Turboprop Engines . . . 538

7.2.4 Equivalent Engine Power . . . 545

7.2.5 Fuel Consumption . . . 546

7.2.6 Analogy with Turbofan Engines . . . 552

7.3 Turboshaft . . . 553

7.3.2 Examples for Turboshaft Manufacturers and Engines . . . 553

7.3.3 Thermodynamic Analysis of Turboshaft Engines . . . 556

7.3.4 Power Generated by Turboshaft Engines . . . 557

7.4 Propfan . . . 564

7.4.2 Historical Hints . . . 565

7.4.3 Classifications of Propfans . . . 567

7.4.4 Comparisons Between Turboprop, Propfan, and Turbofan . . . 569

8 Stationary Modules Intakes, Combustors, and Nozzles. . . 589

8.1 Intake . . . 589

8.1.2 Power Plant Installation . . . 590

8.1.3 Inlet Performance Parameters . . . 619

8.1.4 Subsonic Intakes . . . 621

8.1.5 Supersonic Intakes . . . 637

8.1.6 Hypersonic Inlets . . . 645

8.1.7 Performance Parameters . . . 646

8.2 Combustion Systems . . . 653

8.2.2 Types of Combustion Chamber . . . 653

8.2.3 Components of Combustion Chamber . . . 658

8.2.4 Aerodynamics of Combustion Chamber . . . 661

8.2.5 The Chemistry of Combustion . . . 665

8.2.6 The First Law Analysis of Combustion . . . 668

8.2.7 Combustion Chamber Performance . . . 669

8.2.8 Material . . . 672

8.2.9 Aircraft Fuels . . . 672

8.2.10 Emissions and Pollutants . . . 674

8.2.11 Afterburner . . . 675

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8.3 Exhaust Nozzle . . . 677

8.3.2 Operation of Nozzles . . . 680

8.3.3 Performance Parameters of Nozzles . . . 681

8.3.4 High-Speed Vehicles . . . 689

9 Centrifugal and Axial Compressors. . . 703

9.2 Centrifugal Compressor . . . 703

9.2.2 Layout of Compressor . . . 706

9.2.3 Classification of Centrifugal Compressors . . . 708

9.2.4 Governing Equations . . . 711

9.2.5 Slip Factor (σ) . . . 718

9.2.6 Types of Impeller . . . 724

9.2.7 Impeller Isentropic Efficiency . . . 728

9.2.8 Radial Impeller . . . 733

9.2.9 Diffuser . . . 735

9.2.10 Prewhirl . . . 737

9.2.11 Discharge System . . . 742

9.2.12 Compressor Map . . . 742

9.2.13 Surge . . . 746

9.3 Axial Flow Compressor . . . 747

9.3.2 Comparison Between Axial and Centrifugal Compressors . . . 750

9.3.3 Mean Flow (Two-Dimensional Approach) . . . 752

9.3.4 Basic Design Parameters . . . 763

9.3.5 Design Parameters . . . 770

9.3.6 Real Flow in Axial Compressor . . . 773

9.3.7 Simplified Radial Equilibrium Equation (SRE) . . . . 775

9.3.8 Conceptual Design Procedure for Axial Compressor . . . 794

9.3.9 Blade Design . . . 808

9.3.10 Choice of Airfoil Type . . . 812

9.3.11 Compressor Map . . . 813

9.4 Centrifugal and Axial Compressors Material . . . 818

9.5 Closure . . . 819

10 Turbines. . . 839

10.2 Axial Flow Turbines . . . 840

10.2.1 Flow Features . . . 840

10.2.2 Euler Equation . . . 841

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10.2.3 Efficiency and Pressure Ratio . . . 843

10.2.4 Loss Coefficients in Nozzle and Rotor . . . 845

10.2.5 Performance Parameters . . . 846

10.2.6 Free Vortex Design . . . 858

10.2.7 Turbine Cooling Techniques . . . 867

10.2.8 Guide Lines for Axial Turbine Design . . . 870

10.2.9 Turbine Map . . . 872

10.3 Radial Flow Turbine . . . 873

10.3.2 Aero-Thermodynamics of Radial Inflow Turbine . . . 873

10.3.3 Recommended Design Values for Radial Inflow Turbines . . . 879

10.3.4 Radial Versus Axial Turbines . . . 880

10.4 Gas Turbine Engine Matching . . . 885

10.4.2 Compatibility Conditions . . . 885

10.4.3 Single Shaft Gas Turbine Engine . . . 886

10.4.4 Off-Design of Free Turbine Engine . . . 888

11 Rocket Propulsion. . . 907

11.2 History . . . 908

11.2.1 Important Events . . . 908

11.2.2 Future Plans of Rocket and Space Flights (2014 and Beyond) . . . 912

11.3 Classifications of Rockets . . . 912

11.3.1 Method of Propulsion . . . 912

11.3.2 Types of Missiles . . . 912

11.3.3 Launch Mode . . . 913

11.3.4 Range . . . 914

11.3.5 Number of Stages . . . 914

11.4 Rocket Performance Parameters . . . 914

11.4.1 Thrust Force . . . 915

11.4.2 Effective Exhaust Velocity(V_eff). . . 915

11.4.3 Exhaust Velocity (ue) . . . 919

11.4.4 Important Nozzle Relations . . . 920

11.4.5 Characteristic Velocity (C*) . . . 922

11.4.6 Thrust Coefficient (CF) . . . 922

11.4.7 Total Impulse (It) . . . 924

11.4.8 Specific Impulse (Isp) . . . 924

11.4.9 Specific Propellant Consumption . . . 929

11.4.10 Mass Ratio (MR) . . . 929

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11.4.11 Propellant Mass Fraction (ζ) . . . 929

11.4.12 Impulse-to-Weight Ratio . . . 930

11.4.13 Efficiencies . . . 930

11.5 The Rocket Equation . . . 933

11.5.1 Single-Stage Rocket . . . 933

11.5.2 Multistage Rockets . . . 937

11.5.3 Rocket Equation for a Series Multistage Rocket . . . 938

11.5.4 Rocket Equation for a Parallel Multistage Rocket . . . 940

11.5.5 Advantages of Staging . . . 940

11.5.6 Disadvantages of Staging . . . 941

11.6 Chemical Rocket Engines . . . 945

11.6.2 Performance Characteristics . . . 945

11.7 Solid Propellant . . . 946

11.7.2 Composition of a Solid Propellant . . . 948

11.7.3 Basic Definitions . . . 949

11.7.4 Burning Rate . . . 950

11.7.5 Characteristics of Some Solid Propellants . . . 958

11.8 Liquid-Propellant Rocket Engines (LREs) . . . 959

11.8.3 Propellant Feed System of LREs . . . 961

11.8.4 Liquid Propellants . . . 962

11.8.5 Fundamental Relations . . . 965

11.8.6 Pump-Fed System . . . 968

11.8.7 Rocket Pumps . . . 972

11.8.8 Pump Materials and Fabrication Processes . . . 973

11.8.9 Axial Turbine . . . 974

11.9 Hybrid Propulsion . . . 976

11.9.2 Mathematical Modeling . . . 978

11.9.3 Advantages and Disadvantages of Hybrid Engines . . . 980

11.10 Nuclear Rocket Propulsion . . . 981

11.11 Electric Rocket Propulsion . . . 982

11.11.2 Electrostatic Rockets . . . 983

11.11.3 Electrothermal Rockets . . . 983

11.11.4 Electromagnetic Rockets . . . 984

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Appendices. . . 993 Appendix A . . . 993 Appendix B . . . 994 Appendix C . . . 996 Appendix D . . . 999 Index. . . 1003

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Classifications of Aircrafts and Propulsion Systems

1.1 Introduction

Aircraft engine is also denoted as aero engine, airbreathing engines, or aircraft power plant. It acts as the heart of aircraft (being the only source of power in aircrafts) similar to human’s heart. The desire to fly is as old as the known history of man. Winged gods were plenty among all kinds of societies the man started to form in the early ages. These winged figures or figurines are shown on many temples of Egyptian civilization some 5000 B.C., Sumerian Civilization 3500–2500 B.C and Hittite civilization 3000–1000 B.C. Many of these idols of early civilization carried certain common features, namely the powerful body of a lion (representing leader- ship on land), head of a noble man (putting these idols on a more humane perspective), and wings of an eagle for mastering air.

There are also some interesting artifacts found among ancient ruins. A 6 inch wooden model of an aircraft featuring fuselage, wing, and tail (exactly similar to twentieth century civil transports) was found in one of the tombs in Saqqara, Egypt, that dates back to 200 BC (Fig.1.1).

An ornament for a golden delta wing aircraft model dates back to 500–800 A.D.

that is typical to F 102 jet fighter of the 1950s was found in Columbia (Fig.1.2).

Also a golden model found in Central and South America that is identical to Grumman Aircraft X-29 (Fig.1.3).

The axiom saying that “man cannot dream or imagine something that is not a part of his real life experience” makes us puzzled how such early civilizations that knew nothing about flight principals could produce such models that carry present features of aircrafts and same fuselage, wing, and tail construction?!

Flight story is long dated to several 100 years B.C. It started by mankind’s dream of flight by imitating birds. History recorded some distinct cases. The first was due to Daedalus (a famous architect) and his son Icarus who were prisoned in eighteenth century B.C in Crete. Daedalus built wings for himself and Icarus, fashioned with feathers held together with wax. Myth states that Icarus flying too

©Springer-Verlag London 2016

A.F. El-Sayed,Fundamentals of Aircraft and Rocket Propulsion, DOI 10.1007/978-1-4471-6796-9_1

1

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close to the sun god Helios, the wax melted from the heat and he fell to his death.

Another described case also is due to Abbas Ibn Fernas, an Arabic Mathematician and scientist who lived in Cordoba (810–887 AC) and could fly after jumping from a tower. However, ignoring the contribution of the tails of birds in flight control, he fell down and was hurt (but did not die) as he tried to return to ground.

Several Turkish unsuccessful trials were recorded in the last centuries. The author of this book, in his previous book [1], chronicled flight story in terms of milestones Fig. 1.1 Egyptian wooden model (200 BC)

Fig. 1.2 Columbian golden delta wing model (500–800 AD)

Fig. 1.3 Golden model from South America similar to Grumman aircraft X-29

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for both aircraft and engine inventions beginning with Leonardo da Vinci up through the twenty-first century. This book integrated with the previous one [1]

provides a thorough understanding of engine propulsion concepts, including the performance of aero engines. Author of the present book introduces propulsion systems in a rather new flavor to both aviation and aerospace industries. Integrated with aircrafts, appropriate propulsion systems will be identified. An innovatory classification for both military and civil aircrafts will be given. Next, classifications for aero engines will be followed. Appropriate power plants for each category of airplanes will be also highlighted.

1.2 Classifications of Aircrafts 1.2.1 General

Anaircraftmay be defined as avehiclewhich is able toflyby being supported by theair, or in general, theatmosphereof a planet [2]. An aircraft counters the force of gravity by using eitherstatic liftordynamic lift[3]. Althoughrocketsandmissiles also travel through the atmosphere, most are not considered aircraft because they use rocket thrust instead of aerodynamics as the primary means of lift. However, a cruise missilehas to be considered as an aircraft because it relies on a lifting wing or fuselage/body. Based on method of lift, aircrafts may be classified as either lighter than air (AEROSTATS) or heavier than air (AERODYNES) (Fig.1.4).

1.2.2 Aerostats

Aerostatsusebuoyancyto float in the air in much the same way that ships float on the water. They are characterized by one or more large gasbags or canopies, filled with a relatively low density gas such ashelium,hydrogenorhot air, which is less dense than the surrounding air. Aerostats may be further subdivided into powered and unpowered types. Unpowered types are kite which was invented in China 500 B.C., sky lanterns (small hot air balloons; second type of aircraft to fly as invented 300 B.C.), balloons, and blimps.

A powered aerostat mostly denoted asairship or dirigiblecan be steered and propelled through the air usingrudders andpropellers or otherthrust. The main types of airship are non-rigid,semi-rigid, andrigid. Non-rigid (sometimes denoted blimps) are small airships without internal skeletons. Semi-rigid airships are slightly larger and have some form of internal support such as a fixed keel. An example for rigid airship with full skeletons isZeppelin. Although airships are no longer used for passenger transport, they are still used for other purposes such as advertising,sightseeing, surveillance, and research [4]. As demonstrated in Fig.1.4,

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a blimp may be unpowered as well as powered. Figure 1.5 illustrates both unpowered (balloon) and powered (Zeppelin) aerostats.

1.2.3 Aerodynes

Aerodynes, or heavier than air vehicles, resemble almost all types of aircrafts. It pushes air or gas in one direction, so that a reaction occurs (by Newton’s laws of motion) that pushes the aircraft in the other direction. There are four groups of aerodynes, namely, fixed wing aircrafts, rotorcrafts, hybrid fixed/rotary wing, and a fourth group relying upon other methods for generating lift. For fixed wing aircraft (generally denoted as airplane or aeroplane), aerodynamic lift is generated by

Aircrafts (Flight Vehicles)

Lighter than Air (Aerostats)

Flapping- Wing Unpowered Powered or

Dirigible

Rotorcraft Fixed

Wing

Other Methods Heavier than Air

(Aerodynes)

Unpowered Powered Non-rigid

Blimps

Semi-rigid Rigid Kites

Sky Lanterns Balloons

Lifting Body

FanWing Hybrid Fixed/Rotary

Fig. 1.4 Classifications of aircrafts

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forward movement of wings, while forrotorcraftlift is generated by spinning wing- shaped rotors (sometimes called rotary wings). Fixed wing and rotorcraft types may be further divided into powered and unpowered (gliders) types, as will be described in details below. Rotorcrafts may also be divided into same categories of powered and unpowered types, e.g. helicopters and autogyro, respectively. The third group, namely, hybrid fixed/rotary wing aircrafts, is sometimes identified as compound rotorcraft and may include additional thrust engines or propellers and static lifting surfaces. This group has several types, namely, tilt-wing, tiltrotor, mono tiltrotor, mono-tilt-rotor rotary-ring, and coleopter.

The fourth group may be subdivided into three groups, namely:lifting body, flapping-Wing (Ornithopter), and FanWing. Lifting body configuration has an aircraft body shape to produce lift, e.g.Martin-Marietta X-24.Powered lifttypes rely on engine-derived lift for vertical operation either in takeoff, landing, or both.

An ornithopter (fromGreekornithos “bird” and pteron “wing”) is anaircraftthat fliesby flapping its wings. TheFanWingis a recent innovation (starting 2005 in United Kingdom) and represents a completely new class of aircraft. It uses a fixed wing with a cylindrical fan mounted spanwise just above the wing. As the fan spins, it creates airflow backwards over the upper surface of the wing creating lift.

In the succeeding sections heavier than air vehicles or aerodynes will be discussed in details.

1.2.4 Fixed Wing Aircrafts

1.2.4.1 General Classifications

Fixed wing aircrafts are further classified as either powered or unpowered vehicles (Fig. 1.6). Unpowered types may be next subdivided into six types, namely Fig. 1.5 Two types of aerostats (a) Balloon (b) Zeppelin

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gliders, hang gliders, paragliders, sailplanes, kites, and space shuttle in its return mission. Powered aircrafts are next classified based on several aspects. Based on the number of wings, it is mono-plane, biplane, or tri-plane. Based on geometry, it is fixed, variable (swept-back wings), or tailless as illustrated in Fig.1.7. Swept back wings are adopted in some military aircrafts. Wings are swept back when aircraft flies in supersonic speeds. By tailless aircraft, it is meant an aircraft without horizontal tail.

Finally based on wing type, fixed wing aircrafts may be classified as conventional, flying wing, blended wing body (BWB), and hybrid wing body (HWB).

Figure1.8illustrates blended wing body (BWB), while Fig.1.9illustrates a flying wing.

Based on takeoff and landing (TOL), they may be classified as either conventional or enhanced. Enhanced TOL types may be further divided into four categories, namely: Vertical Take Off and Landing (VTOL), Short Take Off and

Fixed Wings Aircrafts

Unpowered Powered

Hang

Mono-

Enhanced TOL Military Civil

Conventional TOL Conventional

Blended Biplane Wing

Tri-plane

Fixed

Sailplane Kite

Variable Glider

Sea Land

STOL VTOL VSTOL STOVL

Paraglider

Tailless

Land TOL Sea Carrier TOL

Hybrid Wing

Amphibian Space

Shuttle

Flying Wing

Fig. 1.6 Classifications of fixed wing aircrafts

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Fig. 1.7 Classification based on geometry

Fig. 1.8 Blended wing body (BWB)

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Landing (STOL), Vertical and/or Short Take-Off and Landing (VSTOL), and Short Take Off and Vertical Landing (STOVL). Atailsitter is a type of VTOL aircraftthat launches and lands on its tail, something akin to aBuck Rogerstype rocket, such as the McDonnell Douglas DC-X Delta Clipper. One of the most famous examples of this type of aircraft is the Ryan X-13 Vertijet. Among the propeller-driven versions were theLockheed XFVand theConvair XFYPogo. It is important here to state some aircraft types may belong to more than one category of this group of enhanced TOL. As an example Harrier aircraft belongs to both VTOL and V/STOL types. This is not a unique case, but it is severally repeated in other classifications hereafter. Figure 1.10 illustrates four types of enhanced TOL aircrafts.

Furthermore, based also on takeoff and landing, fixed wing aircrafts may operate from land or sea carriers. A third classification based on takeoff and landing defines land, sea, and amphibious planes. A seaplane is a fixed-wing aircraft capable of taking off and landing (alighting) on water, while seaplanes which can also take-off and land on airfields are a small subclass calledAmphib ian aircraft (Fig. 1.11). Seaplanes and amphibians are usually divided into two categories based on their technological characteristics: floatplanes and flying boats, which are generally far larger and can carry far more. These aircrafts were sometimes called hydroplanes.

Finally, fixed wings are seen in both civilian and military aircrafts.

Fig. 1.9 Flying wing (B-2 Spirit)

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1.2.4.2 Civil Aircrafts

As outlined above, fixed wings aircrafts may be either classified as civil or military types. Here civil aircrafts will be further discussed. It is decomposed into different groups, namely, commercial transport, agriculture, trainer, firefighting, experimental, research, search and rescue as well as sea/amphibious planes (Fig.1.12).

Fig. 1.10 Enhanced TOL aircrafts

Fig. 1.11 Sea and amphibian aircrafts

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1.2.4.2.1 Agricultural Aircrafts

Agricultural aircrafts(Fig.1.13) areaircrafts that have been built or converted for agriculturaluse – usuallyaerial applicationofpesticides(crop dusting) orfertilizer (aerial topdressing); in these roles, they are referred to as “crop dusters” or “top dressers” [5].

Civil Aircrafts

Commercial

Seaplanes and Amphibious Experimental

Agricultural Trainer Firefighting

Research Search

and Rescue

Fig. 1.12 Classification of civil aircrafts

Fig. 1.13 Agricultural aircraft

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1.2.4.2.2 Trainer

Atraineris anaircraftused to develop piloting or navigational skills in flight crew.

Civilian pilots are normally trained in a light aircraft, with two or more seats to allow for student and instructor. The two seating configurations for trainer aircraft are pilot and instructor side by side or in tandem, usually with the pilot in front and the instructor behind [6]. Training has two phases, namely, basic and advanced.

Fig.1.14illustrates two configurations of trainer aircrafts.

1.2.4.2.3 Firefighting Aircraft

Firefighting aircraft is used in aerial firefighting and normally employed for steep, rocky, high, and unsafe areas. Airtankers or water bombers are fixed- Fig. 1.14 Side-by-side and tandem trainer aircrafts

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wing aircraft fitted with tanks that can be filled on the ground at an air tanker base (like C-130 and Grumman S-2 T) or, in the case offlying boats(CL 215 and Martin Mars Bomber) and amphibious aircraft, by skimming water from lakes, reservoirs, or large rivers. Figure 1.15 illustrates CL 215 aircraft dropping water. Air-tankers may also use non-toxic retardants likeammonium sulfate, which will then act asfertilizersto help the re-growth of plants after the fire.

1.2.4.2.4 Experimental Aircraft

Anexperimental aircraftis anaircraftthat has not yet been fully proven inflight [7]. Often, this implies that new aerospace technologies are being tested on the aircraft. Experimental aircraft is also a specific term referring to an aircraft flown with an experimental categoryAirworthiness Certificate. A notable example of an experimental aircraft is theRutan Voyager(Fig.1.16). It is the first aircraft to fly around the world without stopping or refueling. Model 76 Voyager powered by a piston engine.

Fig. 1.15 Firefighting CL-215 aircraft dropping water

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1.2.4.2.5 Research

Research aircrafts can be identified as two main types, already manufactured aircraft or new designed ones. The first may be employed either as an airborne laboratory (DC-8) or in new projects for testing some operating conditions (transonic, sonic boom, and supersonic researches), flight procedure, and so on. The second is a newly designed aircrafts that incorporate developments in aerodynamic characteristics, material, equipments, systems (stall speed warning), and engine.

Centurion, Helios, and pathfinder are three types for solar-powered aircrafts.

1.2.4.2.6 Search and Rescue Aircrafts (SAR)

Search and rescue aircrafts(SAR) is the search for and provision of aid to people who are in distress or imminent danger like survivors of aircraft downed at sea as well as sailors and passengers of sea vessels in distress. An example for such aircrafts is de Havilland Canada

DHC-5 Buffalo.Air ambulancemay be included to this category. It is used for emergency medical assistancein situations where either a traditional ambulance cannot reach the scene easily or quickly enough, or the patient needs to be transported over a distance or terrain that makes air transportation the most practical transport. King Air, King Air 200, and Pilatus PC 12/45 are examples for air ambulance aircrafts.

1.2.4.2.7 Seaplanes

Seaplanesare aircrafts capable for operating from sea only whileamphibiousones can operate from both sea and land as described above. Examples of early Grumman’s amphibian family are single-engine biplane G-22, twin-engine G-21, G-44, and G-73.

Fig. 1.16 Rutan Voyager

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1.2.4.2.8 Commercial Transport

Commercial transport is an airplane used by airliner to deliver passengers or cargo (freight) for a fare or fee. Passenger aircrafts are now one of the mostly used methods of human transportation and includes numerous types as well be discussed later.

Cargo Aircrafts

A cargo aircraft (also known as freight aircraft or freighter) is designed or converted for the carriage of goods or mail rather than passengers [8]. Cargo airlines are a special category of air service that has grown rapidly in the last three decades to offer express delivery of priority freight. They are usually devoid of passenger amenities, and generally feature one or more large doors for the loading and unloading of cargo. Aircraft designed for cargo flight use have a number of features, refer to Fig. 1.17, that distinguish them from conventional passenger aircraft: a “fat” looking fuselage as displayed in Airbus A300 Beluga Supertransporter, a high-wing to allow the cargo area to sit near the ground like

Fig. 1.17 Cargo Aircrafts (Freighters) Top: An-225 and Bottom A300-600ST, Reproduced by permission from AIRBUS

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Antonov An 225, a large number of wheels to allow it to land at unprepared locations, and a high-mounted tail to allow cargo to be driven directly into and off the aircraft and most important additional strengthening on key structural areas.

Moreover, there is a wide range of aircraft suitable for all kinds of cargo flights, short-, medium-, and long-haul. Based on its capacity, it ranges from smaller aircraft performing short notice flights carrying vital spare parts up to large cargo aircraft able to transport any voluminous goods

Transports Aircrafts

Transport aircrafts are also calledairlinersorairplanes. The first scheduled airline commenced operation in 1914 between Tampa and St. Petersburg in Florida, USA.

Passengers travelled the 35 km distance in a flying boat.

Transport aircrafts may be classified – based on flight speed – to supersonic transport (SST) and subsonic/transonic types (Fig. 1.18). Airplanes that are powered by jet engines are also calledjetliners. Thus Airliners combine both piston engines aircrafts as well as jet engines ones. A supersonic transport (SST) is designed to transport passengers at speeds greater than the speed of sound. The only SSTs to see regular service were Concorde and the Tupolev Tu-144 (Fig.1.19). Both are powered by afterburning turbojet engines. The first passenger flight of the Tu-144 was in June 1978, and the last flight Concorde’s was on November 26, 2003.

Extensive research work by NASA staff is performed to introduce hypersonic transports (will fly in Mach number equal or greater than 5) in the coming decade.

Subsonic/transonic aircrafts are described in details in [9]. Their different classes

Transport Aircrafts

Private

Commuter Regional Executive

Jet (Corporate)

Single Engine

Twin Engines

Medium Haul Short

Haul

Long Haul Supersonic Transport (SST) Subsonic/Transonic Transport

Fig. 1.18 Classification of transport aircrafts

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are private (small), executive jet (corporate), commuter, regional, short haul, medium haul, and long haul.

Small Transport

Small transports (sometimes identified as private or air taxi) are either single- engine or twin-engine aircrafts. Examples for them are Cessna 172 and Beechcraft 58 TC Baron respectively, and both are powered by piston engines. Number of passengers for both types is three and six, respectively.Executiveor corporate jet is private or charter aircraft. It is either powered by turboprop or jet engines. Exam- ples are Raytheon-Beechcraft King Air B300, Cessna Citation II, and Gulfstream.

Figure 1.20 illustrates Gulfstream G650 T2 which first flight was on February 25, 2010.

Commuter

A Commuter aircraft carry 19 or fewer passenger seats also sometimes called feederliners, depending on their size, engines, and seating configurations.

Depending on local and national regulations, a commuter aircraft may not qualify as an airliner and may not be subject to the regulations applied to larger aircraft.

Members of this class of aircraft normally lack such amenities as lavatories and galleys and typically do not carry a flight attendantas an aircrew member. The Fig. 1.19 Tu-144

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Beechcraft 1900, for example, has only 19 seats and powered by twin turboprop engines (Fig.1.21). Other aircraft in this category are the Fairchild Metro,Jetstream 31/41,IPTN CN-235, andEmbraer EMB 110Bandeirante, which are all powered by twin turboprop engines.

Fig. 1.20 Gulfstream G650 T2 executive aircraft

Fig. 1.21 Beechcraft 1900 commuter aircraft

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Regional Airliner

Aregional airliner is a small airliner designed to fly up to 100 passengers, and usually feeding larger carriers’hubs from small markets. This class of airliners is typically flown by the regional airlines that are either contracted by or subsidiaries of the larger airlines. It may be powered byturbofansorturboprops. These airliners, though smaller than aircraft operated by major airlines, are equipped withlavatories and have a flight attendant to look after the in-flight needs of the passengers.

Typical aircraft in this category are the Embraer ERJ 145 powered by two turbofan engines (Fig.1.22). Other aircrafts of this category areBombardier CRJseries and

“Q” (DASH-8) series powered by turbofan engine,ATR 42/72andSaab 340/2000.

The last two aircrafts are powered by turboprop engines. Airlines and their partners sometimes use these for short flights between small hubs or for bringing passengers to hub cities where they may board larger aircraft.

Inaviation, theflight lengthis defined as the time airborne during a flight. Short haul flight is defined as a flight less than 3 h in length, while a medium haul is defined as a flight between 3 and 6 h. A long haul flight is a journey typically made bywide-body aircraftthat involve long distances, typically beyond six and a half hours in length, and often arenon-stop flights.

Short Haul

Typical short haul airliners in the 1960s and 1970s are Aerospatiale Caravelle, Ae´rospatiale Corvette, Hawker Siddeley Trident 1C/1E, BAC One-Eleven,

Fig. 1.22 Embraer ERJ145 regional aircraft

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Douglas DC-9,Tupolev Tu-124,Tupolev Tu-134,Fokker F28,Yakovlev Yak-40 (Fig.1.23),Boeing 737-100,Boeing 737-200,Dassault Mercure, andVFW-614.

Concerning 1980s and 1990s short hauls, they areAirbus A320,Boeing 737-300, Boeing 737-400,Boeing 737-500,BAe 146,Fokker 70,Fokker 100, andYakovlev Yak-42(Fig.1.22). Finally for 2005 and onward, they areEmbraer E-190,Embraer E-195, andBombardier Aerospace C-Series. All aircrafts are powered by turbofan engines.

Medium Haul

Medium haulaircrafts are more common class of airliners (normallynarrow-body or single aisle aircraft). These airliners are generally used with fewer passengers than their wide-body counterparts. Examples include theBoeing 727,757,MD-80/

MD-90series,Airbus A320 family,Tupolev Tu-204,Tu-214,Embraer E-Jets 190&

195, and Tu-334. Older airliners like the Boeing 707,727,McDonnell Douglas DC-8, Fokker F70/F100, VC10, Tupolev, and Yakovlev jets also fit into this category. All these airplanes are powered by turbofan engines. Figure1.24illus- trates Airbus A320 aircraft floating in Hudson River in 15 January 2009. Due to a collision with a flock of birds, both engines were disabled several minutes after takeoff. Pilot made a successful landing in Hudson River, saving the lives of all 150 passengers and five crew.

Fig. 1.23 Aeroflot Yakovlev Yak-40 series Short Haul Aircraft

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Long Haul

Long haulaircrafts are the largest airliners, which are wide-bodyjets and many passengers. These aircraft are frequently twin-aisle aircraft. Aircraft in this category are the Boeing 747, Boeing 767,Boeing 777, Boeing 787, Airbus A300/A310, Airbus A330,Airbus A340,Airbus A380, Airbus A350,Lockheed L-1011 TriStar, McDonnell Douglas DC-10, McDonnell Douglas MD-11 (Fig. 1.25), Tupolev Tu-214,Ilyushin Il-86, andIlyushin Il-96. All aircrafts are powered by turbofan engines.

It is worth mentioning here that several aircrafts are manufactured in two versions, one as a transport and the second as a cargo. Moreover, many transports may be easily converted into cargo aircrafts. However, a few types are designed as a cargo type from cold start.

1.2.4.3 Military Aircrafts

Military aircrafts are either fixed wing or helicopters (Fig.1.26). Both can be further subdivided into combat and non-combat aircrafts.

Fig. 1.24 Medium Haul Airbus A320 aircraft (Reproduced by permission from AIRBUS)

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1.2.4.3.1 Combat Fixed Wing Military Aircrafts

Fixed wing combat aircrafts may be classified into seven categories, namely, fighter, bomber, fighter-bomber, maritime patrol, ground attack, and powered lift as illustrated in Fig.1.27.

Bomber

A bomber is designed to attack ground and sea targets, primarily by dropping bombson them [10]. It is worthy mentioning that the first non-stop transatlantic Fig. 1.25 Long Haul Airbus 380 (Reproduced by permission from AIRBUS)

Military Aircrafts

Fixed Wing Helicopters

Combat Non-Combat Combat Non-Combat

Fig. 1.26 Classification of military aircrafts

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flight in 1919 was made by two British aviators on their heavy twin engine Vickers Vimy Bomber in 16 h trip.

Bomber aircrafts are further divided into tactics and strategic types.

Strategic bombersare primarily designed for long-range strike missions into the enemy’s heartland to destroy strategic targets such as supply bases, bridges, factories, shipyards, and cities. Examples include the: Avro Lancaster, Heinkel He-111,Junkers Ju 88,B-17 Flying Fortress,B-24 Liberator,B-29 Superfortress, B-36 Peacemaker,B-47 Stratojet,B-52 Stratofortress,General Dynamics F-111, Tupolev Tu-16‘Badger’,Tupolev Tu-160‘Blackjack’, andTupolev Tu-95‘Bear’.

Most – if not all – recent strategic bombers arestealth, while older ones are not.

Figure1.28illustrates B-2 strategic stealth bomber (powered by turbofan engines) releasing bombs and Russian strategic bomber Tu-95 Bear (powered by turboprop engines).

Fixed Wing Combat Aircrafts

Bomber Ground

Attack

Enhanced TOL Fighter/

Bomber

Maritime Patrol

Tactics Strategic VTOL STOL VSTOL STOVL

Fighter

Fig. 1.27 Classification of fixed wing combat aircrafts

Fig. 1.28 Stealth strategic bomber B-2 and strategic bomber Tu-95 bear

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Tactical bombersare smaller aircraft that operate in shorter range in the battle zone to attack troops, tanks, and military equipments. Examples for old ones are Junkers Ju 87 Stuka and Ilyushin Il-2 Shturmovik, where both are powered by piston engines. More recent ones areA-10 Thunderbolt II,F-16 Fighting Falcon, Panavia Tornado, Lockheed F-117, Mikoyan MiG-29, and Sukhoi Su-25

‘Frogfoot’, where all are powered by turbofan engines. Some strategic bombers are also stealth like B-2.

Fighter

Afighter aircraftis amilitary aircraftdesigned primarily for air-to-air combat with otheraircraft. Fighters are small, fast, and maneuverable. The term “fighter” is also sometimes used colloquially for dedicated ground-attack aircraft [11]. Early fighters were very small and lightly armed by later standards and were mostly biplanes. ByWorld War II, fighters were predominantly all-metalmonoplaneswith wing-mounted batteries ofcannonsormachine guns.

Grumman F7F-3 Tigercat and Lavochkin La-9 were some of the last Grumman piston engine fighters. By the end of the war, turbojet engines were already beginning to replace piston engines as the means of propulsion, and increasingly sophisticated refinements to armament were already appearing. Modern jet fighters are predominantly powered by one or two turbofanengines and are equipped with radaras the primary method oftarget acquisition. Armament consists primarily ofair-to-air missiles(from as few as two on some lightweight day fighters to as many as eight or twelve on air superiority fighters like the Sukhoi Su-27 or Boeing F-15 Eagle; Fig. 1.29), with a cannon as backup armament (typically between 20 and 30 mm);

however, they can also often employair-to-surface missiles, as well as guided and unguided bombs.

In brief, any fighter aircraft belongs to one of six groups. First generation group subsonic jet fighters from mid-1940s to mid-1950s, second generation include jet fighters from mid-1950s to early 1960s, third-generation jet fighters resembles the period from early 1960s to circa 1970, fourth generation outline jet fighters of circa 1970 to mid-1990s, 4.5th generation jet fighters available from 1990s to 2005, and lastly, the fifth generation includes jet fighters from 2005 up to present.

Fighter-Bomber

Many fighters have secondary ground-attack capabilities, and some are dual-role as fighter-bombers. A strike fighter is an American designation for afighter-bomber, examples are Su-7, Su-24, Su-34, F-111, and F-15 Eagle, [12]. A multi-role capable combat aircraft set up to operate primarily in the tactical bombingrole. All are powered by afterburning turbofan engines.

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Ground-Attack

Ground-attack aircraftis also identified asattack aircraft,fighter-bomber,tactical fighter,tank-buster,tactical bomber,strafer, andstrike aircraft. It is designed to attack targets on the ground and is often deployed asclose air support. Examples include the AmericanA-10 Thunderbolt II(powered by turbofan engine) and the RussianSukhoi Su-25Frogfoot (powered by turbojet engine). Their role is tactical rather than strategic.

Maritime Patrol

Amaritime patrol aircraft, also simplypatrol aircraft, or by the older termpatrol bomber, is afixed-wing aircraftdesigned to operate for long durations over water in Fig. 1.29 Fighter aircrafts: Sukhoi Su-27 andBoeing F-15 Eagle

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maritime patrol, anti-shipping,anti-submarine(ASW), and search and rescue roles.

Examples for this group during Cold War and Modern eras are Beriev Be-12 (Russia), Ilyushin Il-38 (Russia), Boeing P-8 Poseidon (USA), Lockheed P-2 Neptune (USA), Atlantique ATL3 – Maritime (France), CASA CN-235, C-295 Persuader(Spain),Canadair CP-107 Argus(Canada),Fokker F-27 Maritime(Neth- erlands), Hawker-Siddeley Nimrod (UK), and PZL M28B Bryza 1R (Poland).

Some of these aircrafts are powered by turbofan engines, while others are powered by turboprop engines as seen in Fig.1.30.

Enhanced Takeoff and Landing (TOL)

Enhanced Takeoff and Landing (TOL) typesrefer toaircrafts that cantake off and land verticallyand function differently from arotorcraftin horizontal flight. It is subdivided into four main categories; VTOL, STOL, V/STOL, and STOVL. They stand for vertical takeoff and landing, short takeoff and landing, short and/or vertical takeoff, and lastly short takeoff and vertical landing, respectively. A list of all VTOL aircraft is listed in [13]. The two famous examples for vectored thrust aircrafts are F 35 (Fig.1.10) and Harrier II (Fig.1.31) aircrafts.

F-35 is powered by a single F135 turbofan engine with a lift fan, roll posts, and rear vectoring nozzle.

Harrier aircrafts has four famous versions and powered by turbofan engines with four swiveling nozzles.

There were also some experimental/prototypes for VTOL aircraft which are tailless. Examples include theRyanX-13A-RY Vertijet, Ryan Model 69,Lockheed XFV, and Convair XFY Pogo.RyanX-13A-RY Vertijet powered by a single RR Avon Turbojet engine (1950s),Lockheed XFV(tailsitter prototype), and Convair XFY Pogotailsitterpowered by a 5500 hpAllison YT40-A-16turboprop engine.

Fig. 1.30 Maritime patrol aircraft Atlantique ATL3, France

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1.2.4.3.2 Non-combat Fixed Wing Military Aircrafts

As shown in Fig.1.32, non-combat military aircrafts may be assembled into the following groups, namely, transport, tanker (refueler), trainer, experimental, Fig. 1.31 Harrier II enhanced TOL aircraft

Non-Combat Military Aircrafts

Transport

Surveillance Trainer Tanker

AWACS UAV

Gliders

Experimental

Reconnaissance Fire Fighting

Fig. 1.32 Classification of fixed wing non-combat military aircrafts

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gliders, firefighting, and surveillance. Moreover, surveillance aircrafts may be further subdivided into three subgroups: reconnaissance, UAV, and AWACS.

Transport

Military transport aircraftare typically fixed wing cargo aircraft, which are used to deliver troops, weapons, and other military equipment by a variety of methods to any area of military operations outside of the commercial flight routes in uncontrolled airspace. Some military transport aircraft are tasked to perform multi-role duties such as aerial refueling and tactical, operational and strategic airliftsonto unprepared runways, or those constructed by engineers. Examples for these aircrafts are An-24, Il- 112, C-130, and Airbus A400 M, which are powered by turboprop engines. Others are An -124, Il -76, Galaxy C-5, C-17, C-141B, Kawasaki C-1, and C-X, which are powered by turbofan engines.

Aerial Refueling

Aerial refueling, also called air refueling, in-flight refueling (IFR), air-to-air refueling (AAR), or tanking, is the process of transferring fuel from one aircraft (the tanker) to another (the receiver) during flight. Figure1.33 illustrates USAD KC-135R is refueling US Navy F-16. Other refuelers areAirbus A400M,Boeing C-135,KC-10 Extender,KC-135 Stratotanker,Vickers VC-10, andIl-78. All these

Fig. 1.33 Airbus A400M refueling a Spanish Air Force F/A-18 Hornet (Reproduced by permission from AIRBUS)

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aircrafts are powered by turbofan engines, except Airbus A400M which is powered by turboprop engines.

Trainer

A military trainer is an aircraft used to develop piloting, navigational, or war-fighting skills in flight crew. Several training phases are followed which starts usually withturboproptrainers like thePilatus PC-9andEmbraer Tucano. The final phase includes training for fast jet flying. Examples of such jet trainer aircraft include theT-38 Talon(actually capable of supersonic speeds), theBAE Hawk, the Dassault/Dornier Alpha Jet, and the Aero L-39. All are powered by turbofan engines except for T-38, which is powered by afterburning turbojet engine.

Surveillance

A surveillance aircraftare used for monitoring enemy activity, usually carrying no armament. A surveillance aircraft does not necessarily require high-performance capability orstealthcharacteristics. Technically, anything which can fly and make observations (dynamically or via recording equipment/sensors) of visual information or electronic emissions qualifies as a surveillance aircraft. Surveillance aircraft are either reconnaissance, unmanned aerial vehicle (UAV), or Airborne Warning and Control System (AWACS).

Airborne Reconnaissance

An airborne reconnaissance goes back to the early era ofballooning. The first reconnaissance flights took place during the Balkan wars in October 1912 by (Albatros) aircraft. One of the first aircrafts used for surveillance was theRumpler TaubeduringWorld War I. Japanese builtMitsubishi Ki-46twin-engine reconnaissance aircraft in 1939. Fighters such as the BritishSpitfire,Mosquito, the American P-38 Lightning, andP-51 Mustangwere adapted for photo-reconnaissance during World War II. After World War II, long range aerial reconnaissance was taken up by adapted bombers like theEnglish Electric Canberraand the AmericanMartin B-57. The first purpose-built jet covert surveillance aircraft, namely, theLockheed U-2was constructed secretly for the United States. Modified versions of the U-2 remain in service in 2007. In the 1960s theSR-71 Blackbird, the fastest manned jet-propelled aircraft ever built, was constructed as strategic reconnaissance aircraft.

There are claims that the USA constructed a new, secret,hypersonicsurveillance aircraft – dubbed theAurora– in the late 1980s, but no confirmation of this has ever emerged. Another category of surveillance aircraft that has been in vogue since World War II is the maritime patrol aircraft. These are typically large, slow machines capable of flying continuously for many hours, with a wide range of sensors and electronic equipments on board. Such aircraft include theAvro Shack leton (powered by piston engines), the Hawker-Siddeley Nimrod (powered by

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turbofan), the Breguet Atlantique, the P-3 Orion and the Tupolev Tu-95 (all powered by turboprop), and the P-2Neptune(powered by radial engines). More- over, finally, every fighter plane and ground attack plane can be used to perform surveillance (recent example isF-35 Joint Strike Fighter).

The second group of surveillance aircrafts isunmanned aerial vehicle(UAV).

UAV

Remotely piloted vehicle(RPV), orunmannedaircraft system (UAS),is an aircraft that flies without a human crew on board the aircraft. Their largest uses are in reconnaissance as well as attack missions. UAV is defined as a reusable, uncrewed vehicle capable of controlled, sustained, level flight and powered by a jet or reciprocating engine. There are a wide variety of UAV shapes, sizes, configurations, and characteristics [14]. UAVs come in two varieties: some are controlled from a remote location, and others fly autonomously based on pre-programmed flight plans using more complex dynamic automation systems. Figure1.34illus- trates AMQ-9 Reaper, ahunter-killer surveillance UAV used by the USAF and British Armed Forcesand powered by a 950-shaft-horsepower(712 kW)turboprop engine.

Airborne Warning and Control System (AWACS)

AnAirborne Warning and Control System(AWACS) aircraft is designed to carry outsurveillanceand C2BM (command and control, battle management) functions.

Fig. 1.34 MQ-9 Reaper, Hunter-KillerSurveillance UAV