Conceptual Aircraft Design

Dr. Ajoy Kumar Kundu, PhD, FRAeS, FIMechE, CEng, is a former Professor (IIT, Kharagpur), Chief Aircraft Designer (HAL) and retired from Bombardier, Belfast. He is current honorary visiting faculty member in the School of Mechanical and Aerospace Engineering (QUB). He held private pilot licence. Professor Mark A. Price, PhD, CEng, FRAeS, FIMechE, is Pro-Vice-Chancellor for the Faculty of Engineering and Physical Sciences at Queen's University Belfast (QUB). David Riordan, MSc, CEng, is Engineering Fellow, Nacelle Design and Powerplant Integration at Bombardier, Belfast, having previously been Chief Technical Engineer.

• Series Preface xxxviiPreface xxxixIndividual Acknowledgements By Ajoy Kumar Kundu xliBy Mark A. Price xlvBy David Riordan xlviiList of Symbols and Abbreviations xlixRoad Map of the Book lviiPart I Prerequisites 11 Introduction 31.1 Overview 31.2 Brief Historical Background 41.3 Aircraft Evolution 101.4 Current Aircraft Design Trends for both Civil and Military Aircraft (the 1980s Onwards) 131.5 Future Trends 161.6 Forces and Drivers 231.7 Airworthiness Requirements 231.8 Current Aircraft Performance Analyses Levels 251.9 Aircraft Classification 261.10 Topics of Current Research Interest Related to Aircraft Design (Supersonic/Subsonic) 271.11 Cost Implications 301.12 The Classroom Learning Process 301.13 Units and Dimensions 341.14 Use of Semi-Empirical Relations and Datasheets 341.15 The Atmosphere 36References 452 Aircraft Familiarity, Aircraft Design Process, Market Study 462.1 Overview 462.2 Introduction 472.3 Aircraft Familiarisation 482.4 Typical Aircraft Design Process 532.5 Market Survey – Project Identification 532.6 Four Phases of Aircraft Design 572.7 Typical Task Breakdown in Each Phase 622.8 Aircraft Specifications forThree Civil Aircraft Case Studies 672.9 MilitaryMarket – Some TypicalMilitary Aircraft Design Specifications 702.10 Airworthiness Requirements 732.11 Coursework Procedures – Market Survey 75References 763 Aerodynamic Fundamentals, Definitions and Aerofoils 783.1 Overview 783.2 Introduction 793.3 Airflow Behaviour – Laminar and Turbulent 803.4 Flow Past an Aerofoil 843.5 Generation of Lift 853.6 Aircraft Motion, Forces and Moments 863.7 Definitions of Aerodynamic Parameters 913.8 Aerofoils 913.9 Reynolds Number and Surface Condition Effects on Aerofoils – Using NACA Aerofoil Test Data 1013.10 Centre of Pressure and Aerodynamic Centre 1053.11 Types of Stall 1093.12 High-Lift Devices 1103.13 Flow Regimes 1123.14 Summary 1173.15 Aerofoil Design and Manufacture 1233.16 Aircraft Centre of Gravity, Centre of Pressure and Neutral Point 125References 1254 Wings 1274.1 Overview 1274.2 Introduction 1284.3 GenericWing Planform Shapes 1284.4 Wing Position Relative to Fuselage 1324.5 Structural Considerations 1364.6 Wing Parameter Definitions 1374.7 Spanwise Variation of Aerofoil t/c and Incidence 1394.8 Mean Aerodynamic Chord (MAC) 1404.9 Wing Aerodynamics 1454.10 Wing Load 1534.11 Compressibility Effect:Wing Sweep 1604.12 TransonicWings 1674.13 SupersonicWings 1674.14 Additional Vortex Lift – LE Suction 1704.15 High-Lift Devices on theWing – Flaps and Slats 1704.16 Additional Surfaces on theWing 1754.17 The Square-Cube Law 1764.18 Influence ofWing Area and Span on Aerodynamics 1774.19 Summary ofWing Design 179References 1835 Bodies – Fuselages, Nacelle Pods, Intakes and the Associated Systems 1845.1 Overview 1845.2 Introduction 185CIVIL AIRCRAFT 1885.3 Fuselage Geometry – Civil Aircraft 1885.4 Fuselage Closures – Civil Aircraft 1895.5 Fuselage Fineness Ratio (FR) 1925.6 Fuselage Cross-Sectional Geometry – Civil Aircraft 1945.7 Fuselage Abreast Seating – Civil Aircraft 1955.8 Cabin Seat Layout 1975.9 Fuselage Layout 2055.10 Fuselage Aerodynamic Considerations 2065.11 Fuselage Pitching Moment 2085.12 Nacelle Pod – Civil Aircraft 2135.13 Exhaust Nozzles – Civil Aircraft 220MILITARY AIRCRAFT 2225.14 Fuselage Geometry – Military Aircraft 2225.15 Pilot Cockpit/Flight Deck – Military Aircraft 2245.16 Engine Installation – Military Aircraft 224References 2286 Empennage and Other Planar Surfaces 2296.1 Overview 2296.2 Introduction 2306.3 Terminologies and Definitions of Empennage 2316.4 Empennage Mount and Types 2326.5 Different Kinds of Empennage Design 2356.6 Empennage Tail Arm 2376.7 Empennage Aerodynamics 2406.8 Aircraft Control System 2566.9 Aircraft Control Surfaces and Trim Tabs 2596.10 Empennage Design 2626.11 Other Planar Surfaces 264References 2677 Aircraft Statistics, Configuration Choices and Layout 2687.1 Overview 2687.2 Introduction 269CIVIL AIRCRAFT 2707.3 Civil Aircraft Mission (Payload Range) 2707.4 Civil Subsonic Jet Aircraft Statistics (Sizing Parameters) 2717.5 Internal Arrangements of Fuselage – Civil Aircraft 2827.6 Some Interesting Aircraft Configurations – Civil Aircraft 2887.7 Summary of Civil Aircraft Design Choices 291MILITARY AIRCRAFT 2927.8 Military Aircraft: Detailed Classification, Evolutionary Pattern and Mission Profile 2927.9 Military Aircraft Mission 2997.10 Military Aircraft Statistics (Regression Analysis) 2997.11 Military Aircraft Component Geometries 3047.12 Miscellaneous Comments 3107.13 Summary of Military Aircraft Design Choices 310References 311Part II Aircraft Design 3138 Configuring Aircraft – Concept Definition 3158.1 Overview 3158.2 Introduction 317CIVIL AIRCRAFT 3218.3 Prerequisites to Initiate Conceptual Design of Civil Aircraft 3218.4 Fuselage Design 3258.5 Wing Design 3278.6 Empennage Design 3308.7 Nacelle and Pylon Design 3348.8 Undercarriage 3378.9 Worked-Out Example: Configuring a Bizjet Class Aircraft 337MILITARY AIRCRAFT 3508.10 Prerequisite to Initiate Military (Combat/Trainer) Aircraft Design 3508.11 Fuselage Design (Military – Combat/Trainer Aircraft) 3548.12 Wing Design (Military – Combat/Trainer Aircraft) 3568.13 Empennage Design (Military – Combat/Trainer Aircraft) 3588.14 Engine/Intake/Nozzle (Military – Combat/Trainer Aircraft) 3608.15 Undercarriage (Military – Combat/Trainer Aircraft) 3618.16 Worked-Out Example – Configuring Military AJT Class Aircraft 3618.17 Turboprop Trainer Aircraft (TPT) 374References 3839 Undercarriage 3849.1 Overview 3849.2 Introduction 3859.3 Types of Undercarriage 3879.4 Undercarriage Description 3889.5 Undercarriage Nomenclature and Definitions 3919.6 Undercarriage Retraction and Stowage 3939.7 Undercarriage Design Drivers and Considerations 3949.8 Tyre Friction with the Ground: Rolling and Braking Friction Coefficient 3969.9 Load on Wheels and Shock Absorbers 3979.10 Energy Absorbed 4009.11 Equivalent Single Wheel Load (ESWL) 4029.12 Runway Pavement 4039.13 Airfield/Runway Strength and Aircraft Operating Compatibility 4049.14 Wheels and Tyres 4079.15 Tyre Nomenclature, Classification, Loading and Selection 4119.16 Configuring Undercarriage Layout and Positioning 4149.17 Worked-Out Examples 4179.18 Discussion and Miscellaneous Considerations 426References 42710 Aircraft Weight and Centre of Gravity Estimation 42810.1 Overview 42810.2 Introduction 42910.3 The Weight Drivers 43110.4 Aircraft Mass (Weight) Breakdown 43210.5 Aircraft CG and Neutral Point Positions 43310.6 Aircraft Component Groups 43610.7 Aircraft Component Mass Estimation 438CIVIL AIRCRAFT 44310.8 Mass Fraction Method – Civil Aircraft 44310.9 Graphical Method – Civil Aircraft 44510.10 Semi-Empirical Equation Method (Statistical) 44610.11 Centre of Gravity Determination 45510.12 Worked-Out Example – Bizjet Aircraft 456MILITARY AIRCRAFT 46110.13 Mass Fraction Method – Military Aircraft 46110.14 Graphical Method to Predict Aircraft ComponentWeight – Military Aircraft 46310.15 Semi-Empirical Equations Method (Statistical) – Military Aircraft 46310.16 CG Determination – Military Aircraft 46810.17 Classroom Example of Military AJT/CAS Aircraft Mass Estimation 46810.18 AJT Mass Estimation and CG Location 47110.19 Classroom Example of a Turboprop Trainer (TPT) Aircraft and COIN Variant Weight Estimation 47210.20 Classroom Worked-Out TPT Mass Estimation and CG Location 47610.21 Summary of Concept Definition 478References 47811 Aircraft Drag 47911.1 Overview 47911.2 Introduction 48011.3 Parasite Drag Definition 48111.4 Aircraft Drag Breakdown (Subsonic) 48211.4.1 Discussion 48311.5 Understanding Drag Polar 48311.6 Aircraft Drag Formulation 48711.7 Aircraft Drag Estimation Methodology (Subsonic) 48811.8 Minimum Parasite Drag Estimation Methodology 48911.9 Semi-Empirical Relations to Estimate Aircraft-Component Parasite Drag 49111.10 Notes on Excrescence Drag Resulting from Surface Imperfections 50011.11 Minimum Parasite Drag 50111.12 ΔCDp Estimation 50111.13 Subsonic Wave Drag 50211.14 Total Aircraft Drag 50311.15 Low-Speed Aircraft Drag at Takeoff and Landing 50311.16 Propeller-Driven Aircraft Drag 50811.17 Military Aircraft Drag 50911.18 Supersonic Drag 50911.19 Coursework Example – Civil Bizjet Aircraft 51111.20 Classroom Example – Subsonic Military Aircraft (Advanced Jet Trainer – AJT) 51911.21 Classroom Example – Turboprop Trainer (TPT) 52211.22 Classroom Example – Supersonic Military Aircraft 52711.23 Drag Comparison 53711.24 Some Concluding Remarks 538References 53812 Aircraft Power Plant and Integration 54012.1 Overview 54012.2 Background 54012.3 Definitions 54312.4 Introduction – Air-Breathing Aircraft Engine Types 54612.5 Simplified Representation of a Gas Turbine (Brayton/Joule) Cycle 55112.6 Formulation/Theory – Isentropic Case (Trend Analysis) 55112.7 Engine Integration to Aircraft – Installation Effects 55612.8 Intake/Nozzle Design 56012.9 Exhaust Nozzle and Thrust Reverser (TR) 56312.10 Propeller 56612.11 Propeller Theory 56812.12 Propeller Performance – Use of Charts, Practical Engineering Applications 572References 57513 Aircraft Power Plant Performance 57713.1 Overview 57713.2 Introduction 57813.3 Uninstalled Turbofan Engine Performance Data – Civil Aircraft 58113.4 Installed Engine Performance Data of Matched Engines to Coursework Aircraft 59013.5 Installed Turboprop Performance Data 59413.6 Piston Engine 59813.7 Engine Performance Grid 60213.8 Some Turbofan Data (OPR = Overall Pressure Ratio) 606References 60714 Aircraft Sizing, Engine Matching and Variant Derivatives 60814.1 Overview 60814.2 Introduction 60914.3 Theory 61014.4 Coursework Exercise – Civil Aircraft Design (Bizjet) 61514.5 Sizing Analysis – Civil Aircraft (Bizjet) 61714.6 Coursework Exercise – Military Aircraft (AJT) 61914.7 Sizing Analysis – Military Aircraft (AJT) 62314.8 Aircraft Sizing Studies and Sensitivity Analyses 62514.9 Discussion 626References 63015 Aircraft Performance 63115.1 Overview 63115.2 Introduction 63215.3 Takeoff Performance 63515.4 Landing Performance 64215.5 Climb Performance 64415.6 Descent Performance 64815.7 Checking of the InitialMaximum Cruise Speed Capability 64915.8 Payload-Range Capability – Derivation of Range Equations 64915.9 In Horizontal Plane (Yaw Plane) – Sustained Coordinated Turn 65115.10 Aircraft Performance Substantiation –Worked-Out Classroom Examples – Bizjet 65315.11 Aircraft Performance Substantiation – Military AJT 66815.12 Propeller-Driven Aircraft – TPT (Parabolic Drag Polar) 67715.13 Summarised Discussion of the Design 678References 68116 Aircraft Cost Considerations 68216.1 Overview 68216.2 Introduction 68316.3 Aircraft Cost and Operational Cost 68616.4 Rapid Cost Modelling 69016.5 Aircraft Direct Operating Cost (DOC) 70116.6 Aircraft Performance Management 707References 710Part III Further Design Considerations 71317 Aircraft Load 71517.1 Overview 71517.2 Introduction 71517.3 Flight Manoeuvres 71817.4 Aircraft Loads 71817.5 Theory and Definitions 71917.6 Limits – Load and Speeds 72017.7 V-n Diagram 72117.8 Gust Envelope 726References 72918 Stability Considerations Affecting Aircraft Design 73018.1 Overview 73018.2 Introduction 73018.3 Static and Dynamic Stability 73118.4 Theory 73618.5 Current Statistical Trends for Horizontal and Vertical Tail Coefficients 74118.6 Stick Force – Aircraft Control Surfaces and Trim Tabs 74118.7 Inherent Aircraft Motions as Characteristics of Design 74318.8 Design Considerations for Stability – Civil Aircraft 74718.9 Military Aircraft – Non-Linear Effects 75018.10 Active Control Technology (ACT) – Fly-by-Wire (FBW) 75218.11 Summary of Design Considerations for Stability 754References 75519 Materials and Structures 75619.1 Overview 75619.2 Introduction 75619.3 Function of Structure – Loading 75919.4 Basic Definitions – Structures 76119.5 From Structure to Material 76219.6 Basic Definitions – Materials 76319.7 Material Properties 76519.8 Considerations with Respect to Design 76619.9 Structural Configuration 77619.10 Materials – General Considerations 78419.11 Metals 78619.12 Wood and Fabric 78819.13 Composite Materials 78819.14 Structural Configurations 79319.15 Rules of Thumb and Concept Checks 80019.16 Finite Element Analysis (FEA)/Finite Element Method (FEM) 804References 80520 Aircraft Manufacturing Considerations 80620.1 Overview 80620.2 Introduction 80820.3 Design for Manufacture and Assembly (DFM/A) 80820.4 Manufacturing Practices 80920.5 Six-Sigma Concept 81120.6 Tolerance Relaxation at the Wetted Surface 81220.7 Reliability and Maintainability (R&M) 81420.8 The Design Considerations 81420.9 ‘Design for Customer’ (A Figure of Merit) 81720.10 Digital Manufacturing Process Management 821References 82421 Miscellaneous Design Considerations 82521.1 Overview 82521.2 Introduction 82621.3 History of FAA – the Role of Regulation 82721.4 Flight Test 83121.5 Contribution by the Ground Effect on Takeoff 83221.6 Aircraft Environmental Issues 83321.7 Flying in Adverse Environments 83821.8 Military Aircraft Flying Hazards 84221.9 End-of-Life Disposal 84221.10 Extended Range Twin-Engine Operation (ETOP) 84321.11 Flight and Human Physiology 84321.12 Some Emerging Scenarios 845References 84622 Aircraft Systems 84722.1 Overview 84722.2 Introduction 84822.3 Environmental Issues (Noise and Engine Emission) 84922.4 Safety Issues 85122.5 Aircraft Flight Deck (Cockpit) Layout 85322.6 Aircraft Systems 86222.7 Flying in Adverse Environments and Passenger Utility 87422.8 Military Aircraft Survivability 878References 88523 Computational Fluid Dynamics 88623.1 Overview 88623.2 Introduction 88723.3 Current Status 88823.4 Approach Road to CFD Analyses 88923.5 Some Case Studies 89223.6 Hierarchy of CFD Simulation Methods 89323.7 Summary of Discussions 896References 89724 Electric Aircraft 89924.1 Overview 89924.2 Introduction 90024.3 Energy Storage 90224.4 Prime Mover – Motors 90524.5 Electric Powered Aircraft Power Train 90624.6 Hybrid Electric Aircraft (HEA) 90824.7 Distributed Electric Propulsion (DEP) 91024.8 Electric Aircraft Related Theory/Analyses 91124.9 Electric Powered Aircraft Sizing 91424.10 Discussion 91624.11 Worked-Out Example 918References 919Appendix A Conversions and Important Equations 920Appendix B International Standard Atmosphere Table Data from Hydrostatic Equations 923Appendix C Fundamental Equations (See Table of Contents for Symbols and Nomenclature.) 926Appendix D Some Case Studies – Aircraft Data 932Appendix E Aerofoil Data 948Appendix F Wheels and Tyres 959Index 965