Advanced Aircraft Design

Although the overall appearance of modern airliners has not changed a lot since the introduction of jetliners in the 1950s, their safety, efficiency and environmental friendliness have improved considerably. Main contributors to this have been gas turbine engine technology, advanced materials, computational aerodynamics, advanced structural analysis and on-board systems. Since aircraft design became a highly multidisciplinary activity, the development of multidisciplinary optimization (MDO) has become a popular new discipline. Despite this, the application of MDO during the conceptual design phase is not yet widespread.

Advanced Aircraft Design: Conceptual Design, Analysis and Optimization of Subsonic Civil Airplanes presents a quasi-analytical optimization approach based on a concise set of sizing equations. Objectives are aerodynamic efficiency, mission fuel, empty weight and maximum takeoff weight. Independent design variables studied include design cruise altitude, wing area and span and thrust or power loading. Principal features of integrated concepts such as the blended wing and body and highly non-planar wings are also covered.

The quasi-analytical approach enables designers to compare the results of high-fidelity MDO optimization with lower-fidelity methods which need far less computational effort. Another advantage to this approach is that it can provide answers to 'what if' questions rapidly and with little computational cost.

Key features:

• Presents a new fundamental vision on conceptual airplane design optimization
• Provides an overview of advanced technologies for propulsion and reducing aerodynamic drag
• Offers insight into the derivation of design sensitivity information
• Emphasizes design based on first principles
• Considers pros and cons of innovative configurations
• Reconsiders optimum cruise performance at transonic Mach numbers
  Advanced Aircraft Design: Conceptual Design, Analysis and Optimization of Subsonic Civil Airplanes advances understanding of the initial optimization of civil airplanes and is a must-have reference for aerospace engineering students, applied researchers, aircraft design engineers and analysts.

Egbert Torenbeek, Delft University of Technology, The Netherlands
Egbert Torenbeek is Professor Emeritus of Aircraft Design at Delft University of Technology.
He graduated as an engineer in 1961 at TU Delft and in 1964 he became responsible for teaching the Aircraft Preliminary Design course at the department of Aerospace Engineering. After a sabbatical at Lockheed Georgia Company, he became a senior lecturer and full professor of the Aircraft Design chair at TU Delft, initiating research and teaching in computer-assisted aircraft design.

Autorentext
Egbert Torenbeek, Delft University of Technology, The Netherlands
Egbert Torenbeek is Professor Emeritus of Aircraft Design at Delft University of Technology.
He graduated as an engineer in 1961 at TU Delft and in 1964 he became responsible for teaching the Aircraft Preliminary Design course at the department of Aerospace Engineering. After a sabbatical at Lockheed Georgia Company, he became a senior lecturer and full professor of the Aircraft Design chair at TU Delft, initiating research and teaching in computer-assisted aircraft design.

Inhalt
Foreword xv Series Preface xix

Preface xxi

Acknowledgements xxv

1 Design of theWell-Tempered Aircraft 1

1.1 How Aircraft Design Developed 1

1.1.1 Evolution of Jetliners and Executive Aircraft 1

1.1.2 A Framework for Advanced Design 4

1.1.3 Analytical Design Optimization 4

1.1.4 Computational Design Environment 5

1.2 Concept Finding 6

1.2.1 Advanced Design 6

1.2.2 Pre-conceptual Studies 7

1.3 Product Development 8

1.3.1 Concept Definition 10

1.3.2 Preliminary Design 11

1.3.3 Detail Design 13

1.4 Baseline Design in a Nutshell 13

1.4.1 Baseline Sizing 13

1.4.2 Power Plant 15

1.4.3 Weight and Balance 16

1.4.4 Structure 16

1.4.5 Performance Analysis 17

1.4.6 Closing the Loop 18

1.5 Automated Design Synthesis 19

1.5.1 Computational Systems Requirements 19

1.5.2 Examples 20

1.5.3 Parametric Surveys 21

1.6 Technology Assessment 22

1.7 Structure of the Optimization Problem 25

1.7.1 Analysis Versus Synthesis 25

1.7.2 Problem Classification 26

Bibliography 27

2 Early Conceptual Design 31

2.1 Scenario and Requirements 31

2.1.1 What Drives a Design? 31

2.1.2 Civil Airplane Categories 33

2.1.3 Top Level Requirements 35

2.2 Weight Terminology and Prediction 36

2.2.1 Method Classification 36

2.2.2 Basic Weight Components 37

2.2.3 Weight Limits 39

2.2.4 Transport Capability 39

2.3 The Unity Equation 41

2.3.1 Mission Fuel 43

2.3.2 Empty Weight 44

2.3.3 Design Weights 45

2.4 Range Parameter 46

2.4.1 Aerodynamic Efficiency 47

2.4.2 Specific Fuel Consumption and Overall Efficiency 48

2.4.3 Best Cruise Speed 49

2.5 Environmental Issues 51

2.5.1 Energy and Payload Fuel Efficiency 51

2.5.2 'Greener by Design' 54

Bibliography 56

3 Propulsion and Engine Technology 59

3.1 Propulsion Leading the Way 59

3.2 Basic Concepts of Jet Propulsion 60

3.2.1 Turbojet Thrust 60

3.2.2 Turbofan Thrust 61

3.2.3 Specific Fuel Consumption 62

3.2.4 Overall Efficiency 63

3.2.5 Thermal and Propulsive Efficiency 63

3.2.6 Generalized Performance 65

3.2.7 Mach Number and Altitude Effects 66

3.3 Turboprop Engines 67

3.3.1 Power and Specific Fuel Consumption 67

3.3.2 Generalized Performance 68

3.3.3 High Speed Propellers 69

3.4 Turbofan Engine Layout 70

3.4.1 Bypass Ratio Trends 70

3.4.2 Rise and Fall of the Propfan 72

3.4.3 Rebirth of the Open Rotor? 74

3.5 Power Plant Selection 74

3.5.1 Power Plant Location 75

3.5.2 Alternative Fuels 76

3.5.3 Aircraft Noise 77

4 Aerodynamic Drag and Its Reduction 81

4.1 Basic Concepts 81

4.1.1 Lift, Drag and Aerodynamic Efficiency 82

4.1.2 Drag Breakdown and Definitions 83

4.2 Decomposition Schemes and Terminology 84

4.2.1 Pressure and Friction Drag 84

4.2.2 Viscous Drag 85

4.2.3 Vortex Drag 85

4.2.4 Wave Drag 86

4.3 Subsonic Parasite and Induced Drag 87

4.3.1 Parasite Drag 87

4.3.2 Monoplane Induced Drag 90

4.3.3 Biplane Induced Drag 91

4.3.4 Multiplane and Boxplane Induced Drag 94

4.4 Drag Polar Representations 95

4.4.1 Two-term Approximation 95

4.4.2 Three-term Approximation 96

4.4.3 Reynolds Number Effects 97

4.4.4 Compressibility Correction 98

4.5 Drag Prediction 99

4.5.1 Interference Drag 100 4.5.2 Roughness and Excrescence...