AIRCRAFT DESIGN

Aerospace Series List

Introduction to UAV Systems 4e Fahlstrom and Gleason August 2012

Theory of Lift: IntroductoryComputational Aerodynamics with MATLAB®/Octave

McBain August 2012

Sense and Avoid in UAS: Research and Applications Angelov April 2012

Morphing Aerospace Vehicles and Structures Valasek April 2012

Gas Turbine Propulsion Systems MacIsaac and Langton July 2011

Basic Helicopter Aerodynamics, 3rd Edition Seddon and Newman July 2011

Advanced Control of Aircraft, Spacecraft and Rockets Tewari July 2011

Cooperative Path Planning of Unmanned AerialVehicles

Tsourdos et al November 2010

Principles of Flight for Pilots Swatton October 2010

Air Travel and Health: A Systems Perspective Seabridge et al September 2010

Design and Analysis of Composite Structures: Withapplications to aerospace Structures

Kassapoglou September 2010

Unmanned Aircraft Systems: UAVS Design,Development and Deployment

Austin April 2010

Introduction to Antenna Placement & Installations Macnamara April 2010

Principles of Flight Simulation Allerton October 2009

Aircraft Fuel Systems Langton et al May 2009

The Global Airline Industry Belobaba April 2009

Computational Modelling and Simulation of Aircraftand the Environment:Volume 1 – Platform Kinematics and SyntheticEnvironment

Diston April 2009

Handbook of Space Technology Ley, Wittmann Hallmann April 2009

Aircraft Performance Theory and Practice for Pilots Swatton August 2008

Surrogate Modelling in Engineering Design: APractical Guide

Forrester, Sobester, Keane August 2008

Aircraft Systems, 3rd Edition Moir & Seabridge March 2008

Introduction to Aircraft Aeroelasticity And Loads Wright & Cooper December 2007

Stability and Control of Aircraft Systems Langton September 2006

Military Avionics Systems Moir & Seabridge February 2006

Design and Development of Aircraft Systems Moir & Seabridge June 2004

Aircraft Loading and Structural Layout Howe May 2004

Aircraft Display Systems Jukes December 2003

Civil Avionics Systems Moir & Seabridge December 2002

AIRCRAFT DESIGNA Systems Engineering Approach

Mohammad H. SadraeyDaniel Webster College, New Hampshire, USA

A John Wiley & Sons, Ltd., Publication

This edition first published 2013© 2013, John Wiley & Sons, Ltd

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Library of Congress Cataloging-in-Publication Data

Sadraey, Mohammad H.Aircraft design : a systems engineering approach / Mohammad H. Sadraey.

pages cmIncludes bibliographical references and index.

ISBN 978-1-119-95340-1 (hardback)1. Airplanes–Design and construction. I. Title.

TL671.2.S3136 2012629.134′1–dc23

2012009907

A catalogue record for this book is available from the British Library.

Print ISBN: 9781119953401

Set in 10/12pt Times by Laserwords Private Limited, Chennai, India.

To Fatemeh Zafarani, Ahmad, and AtiehFor all their love and understanding

Contents

Preface xv

Series Preface xix

Acknowledgments xxi

Symbols and Acronyms xxiii

1 Aircraft Design Fundamentals 11.1 Introduction to Design 11.2 Engineering Design 41.3 Design Project Planning 81.4 Decision Making 101.5 Feasibility Analysis 121.6 Tort of Negligence 15

References 17

2 Systems Engineering Approach 192.1 Introduction 192.2 Fundamentals of Systems Engineering 202.3 Conceptual System Design 23

2.3.1 Definition 232.3.2 Conceptual Design Flowchart 242.3.3 Technical Performance Measures 252.3.4 Functional Analysis 262.3.5 System Trade-Off Analysis 272.3.6 Conceptual Design Review 28

2.4 Preliminary System Design 292.5 Detail System Design 302.6 Design Requirements 332.7 Design Review, Evaluation, and Feedback 342.8 Systems Engineering Approach in Aircraft Design 37

2.8.1 Implementation of Systems Engineering 37

viii Contents

2.8.2 Design Phases 382.8.3 Design Flowchart 392.8.4 Design Groups 412.8.5 Design Steps 43References 47

3 Aircraft Conceptual Design 493.1 Introduction 493.2 Primary Functions of Aircraft Components 503.3 Aircraft Configuration Alternatives 52

3.3.1 Wing Configuration 533.3.2 Tail Configuration 553.3.3 Propulsion System Configuration 553.3.4 Landing Gear Configuration 563.3.5 Fuselage Configuration 583.3.6 Manufacturing-Related Items Configuration 583.3.7 Subsystems Configuration 59

3.4 Aircraft Classification and Design Constraints 623.5 Configuration Selection Process and Trade-Off Analysis 683.6 Conceptual Design Optimization 74

3.6.1 Mathematical Tools 743.6.2 Methodology 76Problems 86References 92

4 Preliminary Design 934.1 Introduction 934.2 Maximum Take-Off Weight Estimation 94

4.2.1 The General Technique 944.2.2 Weight Build-up 954.2.3 Payload Weight 964.2.4 Crew Weight 974.2.5 Fuel Weight 1004.2.6 Empty Weight 1084.2.7 Practical Steps of the Technique 112

4.3 Wing Area and Engine Sizing 1134.3.1 Summary of the Technique 1134.3.2 Stall Speed 1184.3.3 Maximum Speed 1204.3.4 Take-Off Run 1314.3.5 Rate of Climb 1364.3.6 Ceiling 140

4.4 Design Examples 145Problems 155References 158

Contents ix

5 Wing Design 1615.1 Introduction 1615.2 Number of Wings 1645.3 Wing Vertical Location 165

5.3.1 High Wing 1655.3.2 Low Wing 1685.3.3 Mid-Wing 1695.3.4 Parasol Wing 1695.3.5 The Selection Process 169

5.4 Airfoil Section 1705.4.1 Airfoil Design or Airfoil Selection 1715.4.2 General Features of an Airfoil 1735.4.3 Characteristic Graphs of an Airfoil 1765.4.4 Airfoil Selection Criteria 1825.4.5 NACA Airfoils 1835.4.6 Practical Steps for Wing Airfoil Section Selection 188

5.5 Wing Incidence 1955.6 Aspect Ratio 1985.7 Taper Ratio 2035.8 The Significance of Lift and Load Distributions 2065.9 Sweep Angle 2095.10 Twist Angle 2235.11 Dihedral Angle 2265.12 High-Lift Device 230

5.12.1 The Functions of a High-Lift Device 2305.12.2 High-Lift Device Classification 2325.12.3 Design Technique 235

5.13 Aileron 2415.14 Lifting-Line Theory 2425.15 Accessories 246

5.15.1 Strake 2475.15.2 Fence 2475.15.3 Vortex Generator 2485.15.4 Winglet 248

5.16 Wing Design Steps 2495.17 Wing Design Example 250

Problems 259References 264

6 Tail Design 2656.1 Introduction 2656.2 Aircraft Trim Requirements 268

6.2.1 Longitudinal Trim 2706.2.2 Directional and Lateral Trim 276

6.3 A Review on Stability and Control 278

x Contents

6.3.1 Stability 2786.3.2 Control 2826.3.3 Handling Qualities 284

6.4 Tail Configuration 2856.4.1 Basic Tail Configuration 2856.4.2 Aft Tail Configuration 288

6.5 Canard or Aft Tail 2946.6 Optimum Tail Arm 2986.7 Horizontal Tail Parameters 301

6.7.1 Horizontal Tail Design Fundamental Governing Equation 3016.7.2 Fixed, All-Moving, or Adjustable 3046.7.3 Airfoil Section 3066.7.4 Tail Incidence 3086.7.5 Aspect Ratio 3116.7.6 Taper Ratio 3126.7.7 Sweep Angle 3136.7.8 Dihedral Angle 3136.7.9 Tail Vertical Location 3146.7.10 Other Tail Geometries 3156.7.11 Control Provision 3166.7.12 Final Check 316

6.8 Vertical Tail Design 3176.8.1 Vertical Tail Design Requirements 3176.8.2 Vertical Tail Parameters 319

6.9 Practical Design Steps 3296.10 Tail Design Example 331

Problems 336References 340

7 Fuselage Design 3417.1 Introduction 3417.2 Functional Analysis and Design Flowchart 3417.3 Fuselage Configuration Design and Internal Arrangement 3457.4 Ergonomics 346

7.4.1 Definitions 3467.4.2 Human Dimensions and Limits 348

7.5 Cockpit Design 3507.5.1 Number of Pilots and Crew Members 3517.5.2 Pilot/Crew Mission 3537.5.3 Pilot/Crew Comfort/Hardship Level 3537.5.4 Pilot Personal Equipment 3547.5.5 Control Equipment 3557.5.6 Measurement Equipment 3567.5.7 Level of Automation 3577.5.8 External Constraints 359

Contents xi

7.5.9 Cockpit Integration 3597.6 Passenger Cabin Design 3607.7 Cargo Section Design 3687.8 Optimum Length-to-Diameter Ratio 372

7.8.1 Optimum Slenderness Ratio for Lowest fLD 3727.8.2 Optimum Slenderness Ratio for Lowest Fuselage Wetted Area 3787.8.3 Optimum Slenderness Ratio for the Lightest Fuselage 380

7.9 Other Fuselage Internal Segments 3807.9.1 Fuel Tanks 3817.9.2 Radar Dish 3857.9.3 Wing Box 3867.9.4 Power Transmission Systems 387

7.10 Lofting 3887.10.1 Aerodynamics Considerations 3887.10.2 Area Ruling 3907.10.3 Radar Detectability 3927.10.4 Fuselage Rear Section 392

7.11 Fuselage Design Steps 3947.12 Design Example 395

Problems 406References 410

8 Propulsion System Design 4138.1 Introduction 4138.2 Functional Analysis and Design Requirements 4148.3 Engine Type Selection 416

8.3.1 Aircraft Engine Classification 4178.3.2 Selection of Engine Type 428

8.4 Number of Engines 4368.4.1 Flight Safety 4378.4.2 Other Influential Parameters 438

8.5 Engine Location 4398.5.1 Design Requirements 4398.5.2 General Guidelines 4418.5.3 Podded versus Buried 4438.5.4 Pusher versus Tractor 4448.5.5 Twin-Jet Engine: Under-Wing versus Rear Fuselage 446

8.6 Engine Installation 4488.6.1 Prop-Driven Engine 4508.6.2 Jet Engine 452

8.7 Propeller Sizing 4568.8 Engine Performance 461

8.8.1 Prop-Driven Engine 4618.8.2 Jet Engine 462

8.9 Engine Selection 462

xii Contents

8.10 Propulsion System Design Steps 4648.11 Design Example 467

Problems 471References 478

9 Landing Gear Design 4799.1 Introduction 4799.2 Functional Analysis and Design Requirements 4819.3 Landing Gear Configuration 484

9.3.1 Single Main 4849.3.2 Bicycle 4859.3.3 Tail-Gear 4879.3.4 Tricycle 4879.3.5 Quadricycle 4889.3.6 Multi-Bogey 4899.3.7 Releasable Rail 4899.3.8 Skid 4899.3.9 Seaplane Landing Device 4909.3.10 Human Leg 4919.3.11 Landing Gear Configuration Selection Process 4929.3.12 Landing Gear Attachment 493

9.4 Fixed, Retractable, or Separable Landing Gear 4949.5 Landing Gear Geometry 497

9.5.1 Landing Gear Height 4989.5.2 Wheel Base 5039.5.3 Wheel Track 508

9.6 Landing Gear and Aircraft Center of Gravity 5169.6.1 Tipback and Tipforward Angle Requirements 5169.6.2 Take-Off Rotation Requirement 518

9.7 Landing Gear Mechanical Subsystems/Parameters 5249.7.1 Tire Sizing 5249.7.2 Shock Absorber 5259.7.3 Strut Sizing 5269.7.4 Steering Subsystem 5279.7.5 Landing Gear Retraction System 527

9.8 Landing Gear Design Steps 5289.9 Landing Gear Design Example 529

Problems 539References 544

10 Weight of Components 54710.1 Introduction 54710.2 Sensitivity of Weight Calculation 54910.3 Aircraft Major Components 55310.4 Weight Calculation Technique 556

10.4.1 Wing Weight 559

Contents xiii

10.4.2 Horizontal Tail Weight 56110.4.3 Vertical Tail Weight 56110.4.4 Fuselage Weight 56210.4.5 Landing Gear Weight 56310.4.6 Installed Engine Weight 56410.4.7 Fuel System Weight 56410.4.8 Weight of Other Equipment and Subsystems 565

10.5 Chapter Examples 565Problems 570References 573

11 Aircraft Weight Distribution 57511.1 Introduction 57511.2 Aircraft Center of Gravity Calculation 57811.3 Center of Gravity Range 585

11.3.1 Fixed or Variable Center of Gravity 58511.3.2 Center of Gravity Range Definition 58611.3.3 Ideal Center of Gravity Location 587

11.4 Longitudinal Center of Gravity Location 59011.5 Technique to Determine the Aircraft Forward and Aft Center of Gravity 59811.6 Weight Distribution Technique 606

11.6.1 Fundamentals of Weight Distribution 60711.6.2 Longitudinal Stability Requirements 60911.6.3 Longitudinal Controllability Requirements 61111.6.4 Longitudinal Handling Quality Requirements 613

11.7 Aircraft Mass Moment of Inertia 61511.8 Chapter Example 620

Problems 624References 630

12 Design of Control Surfaces 63112.1 Introduction 63112.2 Configuration Selection of Control Surfaces 63712.3 Handling Qualities 638

12.3.1 Definitions 64012.3.2 Longitudinal Handling Qualities 64312.3.3 Lateral-Directional Handling Qualities 647

12.4 Aileron Design 65412.4.1 Introduction 65412.4.2 Principles of Aileron Design 65612.4.3 Aileron Design Constraints 66412.4.4 Steps in Aileron Design 669

12.5 Elevator Design 67012.5.1 Introduction 67012.5.2 Principles of Elevator Design 67212.5.3 Take-Off Rotation Requirement 676

xiv Contents

12.5.4 Longitudinal Trim Requirement 68012.5.5 Elevator Design Procedure 683

12.6 Rudder Design 68512.6.1 Introduction to Rudder Design 68512.6.2 Fundamentals of Rudder Design 68812.6.3 Rudder Design Steps 709

12.7 Aerodynamic Balance and Mass Balance 71312.7.1 Aerodynamic Balance 71512.7.2 Mass Balance 722

12.8 Chapter Examples 72312.8.1 Aileron Design Example 72312.8.2 Elevator Design Example 72912.8.3 Rudder Design Example 738Problems 745References 752

Appendices 755Appendix A: Standard Atmosphere, SI Units 755Appendix B: Standard Atmosphere, British Units 756

Index 757

Preface

Objectives

The objective of this book is to provide a basic text for courses in the design of heavier-than-air vehicles at both the upper division undergraduate and beginning graduate levels.Aircraft design is a special topic in the aeronautical/aerospace engineering discipline.The academic major of aeronautical/aerospace engineering traditionally tends to havefour main areas of expertise: aerodynamics, flight dynamics, propulsion, and structure.A qualified aircraft designer employs all these four scientific concepts and principles andintegrates them using special design techniques to design a coordinated unique system;an aircraft . Design is a combination of science, art, and techniques. A designer not onlymust have sufficient level of knowledge in these four areas, but also needs to employmathematics, skills, experiences, creativity, art, and system design techniques. It is truethat aircraft design is not completely teachable in classrooms, but combining class lectureswith a semester-long aircraft design project provides the best opportunity for students tolearn and experience aircraft design.

Every aeronautical engineering discipline offers at least one course in aircraftdesign or aerospace system design. The lack of an aircraft design textbook withacademic features – such as full coverage of all aspects of an air vehicle, aeronauticalconcepts, design methods, design flowcharts, design examples, and end-of-chapterproblems – combined with the newly developed systems engineering techniques was themain motivation to write this book.

In the past several years, I have talked to various aircraft design instructors and stu-dents at conferences and AIAA Design/Build/Fly design competitions. I came to theconclusion that the great design books published by such pioneers as Roskam, Toren-beek, Nicolai, Stinton, and Raymer need more development and expansion. This is tomeet the ever-increasing need of universities and colleges for aircraft design education,and of industries for design implementation. The new text should possess significantfeatures such as systems engineering approaches, design procedures, solved examples,and end-of-chapter problems. This book was written with the aim of filling the gap foraeronautical/aerospace engineering students and also for practicing engineers.

xvi Preface

Approach

The process of air vehicle design is a complex combination of numerous disciplineswhich have to be blended together to yield the optimum design to meet a given setof requirements. The systems engineering approach is defined as an interdisciplinaryapproach encompassing the entire technical effort to evolve and verify an integratedand lifecycle-balanced set of system people, products, and process solutions that satisfycustomer needs. Multi-discipline system engineering design involves the application of asystems engineering process and requires engineers with substantive knowledge of designacross multiple technical areas and improved tools and methods for doing it. Complexaircraft systems, due to the high cost and the risks associated with their development,become a prime candidate for the adoption of systems engineering methodologies. Thesystems engineering technique has been applied in the development of many mannedairplanes. An aircraft is a system composed of a set of interrelated components workingtogether toward some common objective or purpose. Primary objectives include safeflight achieved at a low cost. Every system is made up of components or subsystems,and any subsystem can be broken down into smaller components. For example, in an airtransportation system, the aircraft, terminal, ground support equipment, and controls areall subsystems.

Throughout the text, the systems engineering approach is examined and implemented.The book has been arranged to facilitate the student’s gradual understanding of designtechniques. Statement proofs are provided whenever they contribute to the understandingof the subject matter presented. Special effort has been made to provide example problemsso that the reader will have a clear understanding of the topic discussed. The reader isencouraged to study all such solved problems carefully; this will allow the interestedreader to obtain a deeper understanding of the materials and tools.

Features

Some of the unique features of this textbook are as follows. It:

• follows a systems engineering approach;• is organized based on components design (e.g., wing design, tail design, and fuselage

design);• provides design steps and procedures in each chapter;• derives a number of design equations that are unique to the book;• provides several fully solved design examples at the component level;• has many end-of-chapter problems for readers to practice;• includes a lot of aircraft figures/images to emphasize the application of the concepts;• describes some real design stories that stress the significance of safety in aircraft design;• provides various aircraft configurations, geometries, and weights data to demonstrate

real-world applications and examples;• covers a variety of design techniques/processes so that the designer has freedom and

flexibility to satisfy the design requirements in several ways;• encourages and promotes the creativity of the reader.

Preface xvii

For these reasons, as aeronautical/aerospace engineering students transit to practicingengineers, they will find that this text is indispensable as a reference text. Some materials,such as “design optimization” and “design of control surfaces,” may be taught at thegraduate level. The reader is expected to have a basic knowledge of the fundamentalsand concepts of aerodynamics, propulsion, aero-structure, aircraft performance, and flightdynamics (stability and control) at aeronautical/aerospace engineering senior level.

The following is a true statement: “design techniques are not understood unless prac-ticed.” Therefore, the reader is strongly encouraged to experience the design techniquesand concepts through applied projects. Instructors are also encouraged to define an open-ended semester/year-long aircraft design project to help the students to practice and learnthrough application and experiencing the iterative nature of the design technique. It is mysincere wish that this book will help aspiring students and design engineers to learn andcreate more efficient and safer aircraft.

Outline

The text consists of 12 chapters and is organized in a standard fashion according to thesystems engineering discipline: conceptual design, preliminary design, and detail design.In summary, Chapter 3 presents the aircraft conceptual design; Chapter 4 introduces theaircraft preliminary design; and Chapters 5–12 cover the aircraft detail design. The outlineof this book is as follows.

Chapter 1 is an introduction to design fundamentals and covers such topics as engi-neering design principles, design project planning, decision-making processes, feasibilityanalysis, and tort of negligence. Design standards and requirements such as Federal Avia-tion Regulations (FARs) and Military Standards are reviewed in this chapter, and addressedfurther throughout the text.

Chapter 2 deals with the systems engineering approach. Major design phases accord-ing to systems engineering are introduced: conceptual system design, preliminary systemdesign, and detail system design. In this chapter, several concepts and fundamental def-initions such as technical performance measures, functional analysis, system trade-offanalysis, design review, and design requirements are reviewed. Implementations of sys-tems engineering into aircraft design via aircraft design phases, aircraft design flowcharts,aircraft design groups, and design evaluation and feedback loops are explained. At the endof the chapter, the overall aircraft design procedure in terms of design steps is outlined.

Chapter 3 covers aircraft conceptual design, and examines the aircraft configurationselection. The primary function of each aircraft component such as wing, fuselage, tail,landing gear, and engine is introduced. Furthermore, various configuration alternatives foreach component are reviewed. In addition, the aircraft classification and design constraintsare addressed. In this chapter the design optimization and its mathematical tools are brieflyreviewed. The chapter ends with a configuration selection process and methodology, andalso a trade-off analysis technique.

Chapter 4 discusses the topic of aircraft preliminary design. In this chapter, the tech-nique to determine three aircraft fundamental parameters is presented. These parametersare: maximum take-off weight, wing area, and engine thrust/power. The weight build-up technique is examined for estimation of the aircraft maximum take-off weight. The

xviii Preface

matching plot technique is utilized in the calculation of wing area, and engine thrust/power.These three parameters are computed based on the aircraft performance requirements suchas range, endurance, maximum speed, take-off run, rate-of-climb, and ceiling. Two fullysolved examples illustrate the application of the two techniques.

Chapters 5–9 and 12 present detail design of the aircraft components of wing, tail, fuse-lage, propulsion system, landing gear, and control surfaces respectively. In these chapters,the techniques to calculate all aircraft components parameters such as wing/tail span,chord, airfoil, incidence, sweep angle, tail arm, tail area, landing gear height, wheel base,wheel track, fuselage diameter, fuselage length, cabin design, cockpit design, number ofengines, and engine selection are examined. Furthermore, the features of various compo-nent configurations and their relationship with the design requirements (e.g., performance,stability, control, and cost) are addressed. Chapter 12 introduces the detail design of theconventional control surfaces of aileron, elevator, and rudder. In each chapter, the designflowchart and design step for each component is also presented. Each chapter is accom-panied by several examples, including a fully solved chapter example to demonstrate theapplications of design techniques and methods.

Chapter 10 introduces the technique to calculate the weight of the aircraft components,equipment, and subsystems. The technique is derived mainly based on past aircraft weightdata and statistics.

Chapter 11 addresses the topic of aircraft weight distribution, and weight and balance.The aircraft center of gravity (cg) calculation, aircraft most aft and most forward cg, andcg range are also covered in this chapter. In addition, the technique to determine theaircraft mass moment of inertia about three axes (i.e., x , y , and z ) is examined.

Unit Systems

In this text, the emphasis is on SI units or the metric system, which employs the meter(m) as the unit of length, the kilogram (kg) as the unit of mass, and the second (s) as theunit of time. It is true that metric units are more universal and technically consistent thanBritish units. However, currently, many FARs are published in British units, where thefoot (ft) is the unit of length, the slug is the unit of mass, the pound (lb) is the unit offorce (weight), and the second (s) is the unit of time. In FARs, the pound is used as theunit for force and weight, the knot for airspeed, and the foot for altitude. Thus, in variouslocations, the knot is mainly used as the unit of airspeed, the pound for weight and force,and the foot for altitude. Therefore, in this text, a combination of SI and British unitsystems is utilized. A common mistake in the literature (even in the Jane’s publications)is the application of kg for the unit of aircraft weight. Throughout the text, wheneverthe unit of kg is used, the term “aircraft mass” is employed. Some texts have created thepound-mass (lbm) as the unit of mass, and the pound-force (lbf) as the unit of weight. Thisinitiative may generate some confusion; so in this text, only one pound (lb) is employedas the unit of weight and force.

Series Preface

The field of aerospace is wide ranging and multi-disciplinary, covering a large varietyof products, disciplines and domains, not merely in engineering but in many relatedsupporting activities. These combine to enable the aerospace industry to produce excitingand technologically advanced vehicles. The wealth of knowledge and experience that hasbeen gained by expert practitionersin the various aerospace fields needs to be passed ontoothers working in the industry, including those just entering from University.

The Aerospace Series aims to be a practical and topical series of books aimed atengineering professionals, operators, users and allied professions such as commercial andlegal executives in the aerospace industry. The range of topics is intended to be wideranging, covering design and development, manufacture, operation and support of aircraftas well as topics such as infrastructure operations and developments in research andtechnology. The intention is to provide a source of relevant information that will be ofinterest and benefit to all those people working in aerospace.

Aircraft design brings together the key aeronautical engineering disciplines: aerody-namics, flight dynamics, propulsion and structures, which must be combined to producedesigns that meet today’s stringent performance, economic and environmental demands.As such, aircraft designis a key component of all undergraduate aerospace engineeringcourses, and all aerospace students usually tackle some form of aircraft design project.

This book, Aircraft Design: A Systems Engineering Approach , extends the classicalaircraft design approaches through the implementation of systems engineering techniquesfor the conceptual, preliminary and detailed design of heavier-than-air vehicles. As a veryreadable and informative text reference, with plenty of examples from a wide range ofcontemporary aircraft designs, and solved examples at the end of each chapter, it is aworthy addition to the Wiley Aerospace Series.

Peter Belobaba, Jonathan Cooper, Roy Langton and Allan Seabridge

Acknowledgments

I am enormously grateful to the Almighty for the opportunity to serve the aerospacecommunity by writing this text. The author would like to acknowledge the many con-tributors and photographers who have contributed to this text. I am especially grate-ful to those who provided great aircraft photographs: Anne Deus (Germany); JenneyCoffey (UK); Anthony Osborne (UK); A J Best (UK); Vlamidir Mikitarenko (Ger-many); Rainer Bexten (Germany); Hideki Nakamura (Japan); Akira Uekawa (Japan); LuisDavid Sanchez (Puerto Rico); Tom Houquet (Belgium); Toshi Aoki (Japan); MiloslavStoroska (Slovakia); Tom Otley (Panacea Publishing International, UK); Jonas Lovgren(SAAB, Sweden); Jeff Miller (Gulfstream Aerospace Corporation, USA); Michael deBoer (Netherland); Konstantin von Wedelstaedt (Germany); Augusto G. Gomez R. (Mex-ico); Randy Crew (Singapore); Robert Domandl; Serghei Podlesnii (Moldova); Orlando J.Junior (Brazil); Balazs Farkas (Hungary); and Christopher Huber and www.airliners.net.In addition, the efforts of the author were helped immeasurably by the many insightsand constructive suggestions provided by students and instructors over the past 16 years.Unattributed figures are held in the public domain and are from either the US GovernmentDepartments and Agencies, or Wikipedia.

Putting a book together requires the talents of many people, and talented people aboundat John Wiley & Sons, Inc. My sincere gratitude goes to Paul Petralia, commissioningeditor, for coordinating the whole publication process; Clarissa Lim for coordinating theproduction project; Sarah Lewis for editing the manuscript; Jayashree Saishankar fortypesetting; and Sandra Grayson for helping in the copyright process. I am particularlygrateful to my editors, Liz Wingett and Sophia Travis, for their comments and guidance.My special thanks go to the outstanding copyeditors and proofreaders who are essentialin creating an error-free text. I especially owe a large debt of gratitude to the reviewersof this text. Their ideas, suggestions, and criticisms have helped me to write more clearlyand accurately and have influenced the evolution of this book markedly.

Symbols and Acronyms

Symbols

Symbol Name Unit

a Speed of sound m/s, ft/sa Acceleration m/s2, ft/s2

A Area m2, ft2

AR Aspect ratio –b Lifting surface/control surface span m, ftB Wheel base m, ftC Specific fuel consumption N/h kW, lb/h hpC Mean aerodynamic chord m, ftCD , CL, Cy Drag, lift, and side-force coefficients –Cl, Cm, Cn Rolling, pitching, and yawing moment

coefficients–

Ch Hinge moment coefficient –CDy

Aircraft side drag coefficient –CDβ

Rate of change of drag coefficient w.r.t.sideslip angle; ∂CD

/∂β

1/rad

Cmac_wfWing/fuselage pitching moment coefficient(about the wing/fuselage aerodynamiccenter)

–

CmαRate of change of pitching moment w.r.t.angle of attack

1/rad

CmqRate of change of pitch rate w.r.t. angle ofattack

1/rad

CLδE∂CL

/∂δE 1/rad

CmδE∂Cm

/∂δE 1/rad

ClδA∂Cl

/∂δA 1/rad

CnδR∂Cn

/∂δR 1/rad

CnβRate of change of yawing momentcoefficient w.r.t. sideslip angle

1/rad

CnrRate of change of yawing momentcoefficient w.r.t. yaw rate

1/rad

xxiv Symbols and Acronyms

Symbol Name Unit

CDoZero-lift drag coefficient –

CDiInduced drag coefficient –

Cf Skin friction coefficient –CLα

Wing/tail/aircraft (3D) lift curve slope 1/radClα Airfoil (2D) lift curve slope 1/radCLmax

Maximum lift coefficient –D Drag force, drag N, lbD Diameter m, ftdc Distance between the aircraft cg and center

of the projected side aream, ft

E Endurance h, sE Modulus of elasticity N/m2, Pa, lb/in2, psie Oswald span efficiency factor –F Force, friction force N, lbFC Centrifugal force N, lbFOM Figure of merit –g Gravity constant 9.81 m/s2, 32.17 ft/s2

G Fuel weight fraction –GR Gearbox ratio –GC Ratio between the linear/angular

movement of the stick/wheel to deflectionof the control surface

deg/m, deg/ft, deg/deg

H Altitude m, fth , ho Non-dimensional distance between cg (h)

or ac (ho) and a reference line–

H Height, wheel height m, ftH Control surface hinge moment Nm, lb ftih Tail incidence deg, radiw Wing incidence deg, radl Length, tail arm m, ftI Mass moment of inertia kg m2, slug ft2

I Second moment of area m4, ft4

I Index (e.g., design, performance) –K Induced drag factor –L, LA Rolling moment Nm, lb ftL Length m, ftL Lift force, lift N, lb(L/D)max Maximum lift-to-drag ratio –M Mach number –M , MA Pitching moment Nm, lb ftm mass kg, slug•

m Engine air mass flow rate kg/s, lb/sMTOW Maximum take-off weight N, lbMAC Mean aerodynamic chord m, ftn Load factor –n Number of rows in cabin –

Symbols and Acronyms xxv

Symbol Name Unit

n Rotational speed rpm, rad/sN Normal force N, lbN Number of an item –N , NA Yawing moment Nm, lb ftP Pressure N/m2, Pa, lb/in2, psiP Power W, kW, hp, lb ft/sPs Seat pitch m, ftPreq Required power W, kW, hp, lb ft/sPav Available power W, kW, hp, lb ft/sPexc Excess power W, kW, hp, lb ft/sP , p Roll rate rad/s, deg/sq , q Dynamic pressure N/m2, Pa, lb/in2, psiQ , q Pitch rate rad/s, deg/sQ Fuel flow rate kg/s, lb/sR Range m, km, ft, mile, mi, nmiR Air gas constant 287.26 J/kg KR Radius m, ftR Rank –Re Reynolds number –ROC Rate of climb m/s, ft/min, fpmR, r Yaw rate rad/s, deg/ss Semispan (b/2) m, ftS Planform area of lifting/control surface m2, ft2

SA Airborne section of the take-off run m, ftSG Ground roll m, ftSTO Take-off run m, ftSFC Specific fuel consumption N/h/kW, lb/h/hp, 1/s, 1/ftSM Static margin –t Time s, min, hT Engine thrust N, lbT Temperature ◦C, ◦R, KT Wheel track m, ftT , t Thickness m, ftt /c Airfoil thickness-to-chord ratio –T /W Thrust-to-weight ratio –U Forward airspeed m/s, ft/min, km/h, mi/h, knotV Velocity, speed, airspeed m/s, ft/min, km/h, mi/h, knotV Volume m3, ft3

Vmax Maximum speed m/s, ft/min, km/h, mi/h, knotVmc Minimum controllable speed m/s, ft/min, km/h, mi/h, knotVminD

Minimum drag speed m/s, ft/min, km/h, mi/h, knotVminP

Minimum power speed m/s, ft/min, km/h, mi/h, knotVR Rotation speed m/s, ft/min, km/h, mi/h, knotVROCmax

Maximum rate of climb speed m/s, ft/min, km/h, mi/h, knotVs Stall speed m/s, ft/min, km/h, mi/h, knotVT True speed m/s, ft/min, km/h, mi/h, knot

xxvi Symbols and Acronyms

Symbol Name Unit

VTO Take-off speed m/s, ft/min, km/h, mi/h, knotVW Wind speed m/s, ft/min, km/h, mi/h, knotV H, V V Horizontal/vertical tail volume coefficient –W Weight N, lbW Width m, ftWf Fuel weight N, lbWTO Maximum take-off weight N, lbW /P Power loading N/W, lb/hpW /S Wing loading N/m2, lb/ft2

x , y , z Displacement in x , y , and z direction m, ftY Side force N, lby Beam deflection m, ft

Greek symbols

Symbol Name Unit

α Angle of attack deg, radβ Sideslip angle deg, radγ Climb angle deg, radθ Pitch angle, pitch attitude deg, radλ Taper ratio –φ Bank angle deg, radδ Pressure ratio –δ Control surface deflection deg, radσ Air density ratio –σ Sidewash angle deg, radρ Air density, materials density kg/m3, slug/ft3

μ Dynamic viscosity kg/m s, lb s/ft2

μ Friction coefficient –μ Mach angle rad, degη Efficiency, dynamic pressure ratio – Sweep angle deg, radω Angular velocity rad/s, deg/sωn Natural frequency rad/s, deg/sω Frequency rad/s, deg/sψ Yaw angle, heading angle deg, radπ 3.14 –� Spin rate rad/s, deg/s, rpmτ Control surface angle of attack

effectiveness–

� Dihedral angle deg, radε Downwash angle degr, rad∂ε/∂α Downwash slope –∂σ/∂β Sidewash slope –

••θ Take-off rotation angular acceleration deg/s2, rad/s2

�x cg Non-dimensional range of center of gravity –

Symbols and Acronyms xxvii

Subscripts

Note AR, S , b, λ, , �, and C without a subscript indicate a wing property0, o Zero-lift, sea level, about aerodynamic center0.25 Quarter chord1 Steady-state valuea, A Aileronaft The most aft locationA Aerodynamicac Aerodynamic centeravg Averagea Aircraftb Baggagec/4 Relative to the quarter chordc/2 Relative to the 50% of the chordcs Control surfacecross Cross-sectionC Crew, ceiling, cruise, cabind DesignD Drage, E Elevator, equivalent, empty, exiteff EffectiveE Enginef Fuel, fuselage, flap, frictionfor The most forward locationGL Glideh Horizontal taili Item number, inboard, ideal, initial, inletISA International Standard AtmosphereL Lift, left, landingLG Landing gearmax Maximummin Minimumm Pitching momentmg Main gearmat Materialso Outboardopt Optimumot Overturnp PropellerPL Payloadr, R RudderR Rotationr Rootref References Stall, stickss Steady-stateSL Sea levelS SideSR Spin recovery

xxviii Symbols and Acronyms

t Tip, tab, twist, horizontal tailT TrueTO Take-offtot Totalult Ultimatev, V Vertical tailVT Vertical tailw, W Wing, windwet Wettedwf Wing/fuselagex , y , or z In the x , y , or z directionxx , yy , or zz About the x -, y-, or z -axis

Acronyms

ac or AC Aerodynamic centerca Center of area, center of actioncg or CG Center of gravityAPU Auxiliary power unitCAD Computer-aided designCAM Computer-aided manufacturingCDR Conceptual design reviewCFD Computational fluid dynamicscp Center of pressureDOF Degrees of freedomDOD Department of DefenseEASA European Aviation Safety AgencyETR Evaluation and test reviewFDR Final (critical) design reviewFAA Federal Aviation AdministrationFAR Federal Aviation RegulationsFBW Fly-by-wireGA General aviationHALE High-altitude long-enduranceHLD High-lift deviceIATA International Air Transport AssociationISA International Standard AtmosphereJAR Joint aviation requirementsKTAS Knot true air speedKEAS Knot equivalent air speedLG Landing gearLE Leading edgeMAC Mean aerodynamic chordMDO Multidisciplinary design optimizationMIL-STD Military StandardsNACA National Advisory Committee for AeronauticsNASA National Aeronautics and Space AdministrationNTSB National Transportation Safety Board