Aircraft Design Concepts: An Introductory Course

582 Pages·2022·42.291 MB·English

by  James DeLaurier

Aircraft Design Concepts

Aircraft Design Concepts
An Introductory Course
James DeLaurier
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First edition published 2022
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© 2022 James DeLaurier
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ISBN: 978-1-138-03339-9 (hbk)
ISBN: 978-1-032-11104-9 (pbk)
ISBN: 978-1-315-22816-7 (ebk)
DOI: 10.1201/9781315228167
Typeset in Times LT Std
by KnowledgeWorks Global Ltd.
Dedication
To my Susan

Contents
Preface...............................................................................................................................................xi
Acknowledgements ........................................................................................................................xiii
Author ..............................................................................................................................................xv
Chapter 1 Introduction ..................................................................................................................1
Design Features ............................................................................................................1
Different Materials in Column Buckling .....................................................................6
Illustrative Examples of Wood, Metal and Composite Airplanes ..............................11
Examples Wing Structures .........................................................................................17
Chapter 2 Aerodynamic Review .................................................................................................25
Airfoils .......................................................................................................................25
Wings..........................................................................................................................36
Bodies .........................................................................................................................40
Undercarriage .............................................................................................................46
Wing-Body Combination ...........................................................................................48
Complete-Aircraft Aerodynamics (for a Tail-Aft Monoplane) ..................................49
Lift .........................................................................................................................50
Drag .......................................................................................................................53
Pitching Moment (with non-extended undercarriage) ...........................................55
Pitching Moment (with extended undercarriage) ..................................................60
Numerical Example ....................................................................................................60
Wing ......................................................................................................................61
Tail .........................................................................................................................64
Body.......................................................................................................................70
Propeller ................................................................................................................74
Undercarriage ........................................................................................................74
Complete Airplane Lift and Drag Coefficients .....................................................75
Complete Airplane Moment Characteristics .........................................................76
A Final Comment .......................................................................................................78
Chapter 3 Propeller Analysis ......................................................................................................79
Simple Blade-Element Analysis .................................................................................79
Actuator-Disk Momentum Theory .............................................................................82
Extensions to the Simple Blade-Element Analysis ....................................................84
Method of Calculation ................................................................................................87
Numerical Example ....................................................................................................89
Application of the Analysis ........................................................................................94
Propeller Airfoils ........................................................................................................97
Matlab Program ..........................................................................................................97
Chapter 4 Flying Wings (or Tailless Airplanes) ......................................................................101
“Flying Planks” ........................................................................................................101
Swept Flying Wings .................................................................................................105
vii
viii Contents
Paragliders ................................................................................................................108
Rogallo-Type Hang Gliders ......................................................................................109
Span-Loader Flying Wings ......................................................................................110
A Canadian Flying-Wing Glider ..............................................................................114
An Approximate Method for Estimating the Aerodynamic Characteristics
of Wings with Variable Twist, Taper and Sweep .....................................................115
Example 1, Straight-Tapered Linear-Twisted Wing.............................................118
Example 2, Double-Swept and Double-Tapered Wing ........................................129
Matlab Computer Program ..................................................................................143
“Delta” Tailless Aircraft ..........................................................................................154
Final Observations ...................................................................................................162
Chapter 5 Canard Airplanes and Biplanes ................................................................................167
Canard Airplanes .....................................................................................................167
An Approximate Method for Estimating the Aerodynamic Characteristics
of Canard Airplanes ............................................................................................179
Example, Rectangular Wing ...............................................................................183
Example, Canard Glider ......................................................................................185
Biplanes ....................................................................................................................197
An Approximate Method for Estimating the Aerodynamic Characteristics
of Biplanes with Wings of Equal Spans and Areas .............................................210
Example, “Slow SHARP” Biplane ......................................................................212
Further Considerations of Biplane Analysis ........................................................229
Example, Biplane Glider .....................................................................................232
Final Biplane Comment .......................................................................................243
Chapter 6 Flight Dynamics ......................................................................................................245
Introduction ..............................................................................................................245
Aircraft Longitudinal Small-Perturbation Dynamic Equations ..............................256
Non-Dimensional Form of the Equations ...........................................................259
Estimation of the Longitudinal Stability Derivatives ..........................................264
The ( ) Terms ................................................................................................264
0
The û Derivatives ............................................................................................265
The α Derivatives ............................................................................................266
The qˆ derivatives .............................................................................................267
The Dû Derivatives .........................................................................................271
The Dα Derivatives .........................................................................................273
The Dq Derivatives .........................................................................................276
The Propulsion Derivatives ............................................................................277
Longitudinal Numerical Example (“Scholar” Tail-Aft Monoplane) ...................279
Example Values of (C ) , (C ) and (C ) ......................................................280
X 0 Z 0 M 0
Example Values of CXα, CZα and CMα .............................................................281
Example values of C , C and C ..............................................................282
Xq Zq Mq
Example Values of C and C ................................................................285
XDU MDU
Example Values of C and C .................................................................287
ZDα MDα
Example Values of CXDq, CZDq and CMDq ........................................................289
Example Values of T̂ , T̂ and T̂ ...............................................................292
Xu Xα Zα
Aircraft Lateral Small-Perturbation Dynamic Equations ........................................294
Contents ix
Non-Dimensional Form of the Equations ...........................................................295
Estimation of the Lateral Stability Derivatives ...................................................297
The β Derivatives: ...........................................................................................298
The rˆ Derivatives ............................................................................................314
The pˆ Derivatives: ...........................................................................................319
The Dβ Derivatives: ........................................................................................324
The Drˆ Derivatives .........................................................................................326
The Dpˆ Derivatives .........................................................................................327
Example Lateral Stability Derivatives for the “Scholar”
Tail-Aft Monoplane .............................................................................................329
Example Value of C .....................................................................................329
Yβ
An Extension to the Analysis .........................................................................331
Example Value of C .....................................................................................337
Nβ
Example Value of C .....................................................................................339
L˜β
Example Value of C .....................................................................................340
Yr
Example Value of C ....................................................................................341
Nr
Example Value of C ......................................................................................343
L˜r
Example Value of C ....................................................................................344
Yp
Example Value of C ....................................................................................345
Np
Example Value of C ....................................................................................346
L˜p
Example Value of C ..................................................................................348
YDβ
Example Value of C ..................................................................................349
NDβ
Example Value of C ..................................................................................350
L˜Dβ
Example Value of C ...................................................................................351
YDr
Example Value of C ..................................................................................352
NDr
An Extension to the Analysis .........................................................................352
Example Value of C ...................................................................................354
L˜Dr
Example Value of C ..................................................................................354
YDp
Example Value of C ..................................................................................355
NDp
Example Value of C ..................................................................................356
L˜Dp
An Extension to the Analysis .........................................................................356
Radii-of-Gyration Values for Representative Airplanes ..........................................359
Definitions of Stability .............................................................................................360
Longitudinal Dynamic Stability ..............................................................................362
Numerical Example .............................................................................................366
Comments on α and θ ..........................................................................................368
Flight Paths ..........................................................................................................369
Approximate Equations .......................................................................................374
Short-Period Mode ..........................................................................................374
Phugoid Mode .................................................................................................376
Roots-Locus Plots ................................................................................................378
Lateral Dynamic Stability ........................................................................................382
Flight Paths ..........................................................................................................386
Approximate Equations .......................................................................................392
Spiral Mode ....................................................................................................393
Rolling Mode ..................................................................................................394
Dutch-Roll Mode ............................................................................................395
Roots-Locus Plots ................................................................................................396
Stability-Boundary Plot .......................................................................................398
Addendum ................................................................................................................399