Bramwell’s Helicopter Dynamics

A. R. S. Bramwell, George Taylor Sutton Done, David Balmford9780750650755, 0-7506-5075-3

Since the original publication of Helicopter Dynamics by A.R.S. Bramwell in 1976, this book has become the definitive text on helicopter dynamics. As such it is an essential aid to those studying the behavior of helicopters. The second edition builds on the strengths of the original, and hence the approach of the first edition is retained. The authors provide a detailed summary of helicopter aerodynamics, stability, control, structural dynamics, vibration, and aeroelastic and aeromechanical stability. Bramwell’s Helicopter Dynamics is essential for all those in helicopter engineering, whether student or professional.

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Table of contents :
Contents……Page 4
Preface to the second edition……Page 5
Preface to the first edition……Page 7
Acknowledgements……Page 9
Notation……Page 10
Suffices……Page 23
1.2 The rotor hinge system……Page 25
1.3 The flapping equation……Page 31
1.4 The equation of lagging motion……Page 33
1.6 Flapping motion in hovering flight……Page 34
1.7 The cyclic and collective pitch control……Page 41
1.8 Lagging motion……Page 42
1.9 Lagging motion due to flapping……Page 43
1.10 Feathering motion……Page 44
1.11 Rotor forces and moments……Page 45
1.12 Rotor forces and choice of axes……Page 50
1.13 The rotor disc……Page 51
1.14 Longitudinal trim equations……Page 52
1.16 Lateral control to trim……Page 54
2.1 Introduction……Page 57
2.2 Actuator disc theory……Page 58
2.3 Vertical descent and the vortex ring state……Page 66
2.4 The swirl velocity……Page 68
2.5 Blade element theory in vertical flight……Page 70
2.6 Calculation of the inflow angle……Page 76
2.7 The optimum rotor……Page 78
2.8 The efficiency of a rotor……Page 79
2.9 Ground effect on the lifting rotor……Page 81
2.10 Rotor wake models……Page 83
3.2 Induced velocity in forward flight……Page 101
3.3 The method of Mangler and Squire……Page 105
3.4 Flight and wind tunnel tests……Page 108
3.5 General remarks on the forward flight case……Page 112
3.6 Induced power in forward flight……Page 114
3.7 Velocity components at the blade……Page 116
3.8 Calculation of the rotor thrust……Page 120
3.9 The in-plane force……Page 122
3.10 The rotor torque, Q……Page 124
3.11 Blade flapping……Page 127
3.12 The flapping coefficients……Page 130
3.13 Force and torque coefficients referred to disc axes……Page 132
3.14 Comparison with experiment……Page 133
4.1 Introduction……Page 139
4.2 Helicopter trim in forward flight……Page 140
4.3 Helicopter performance in forward flight……Page 151
5.1 Introduction……Page 161
5.2 The longitudinal equations of motion……Page 164
5.3 Longitudinal dynamic stability……Page 167
5.4 Calculation of the derivatives……Page 171
5.5 The longitudinal stability characteristics……Page 184
5.6 Lateral dynamic stability……Page 190
5.7 The lateral stability characteristics……Page 196
5.8 Autostabilisation……Page 199
5.9 Control response……Page 203
6.2 The vortex wake……Page 220
6.3 Aerofoil characteristics in forward flight……Page 245
6.4 Aerofoil characteristics when oscillating at conditions of high incidence……Page 249
6.5 The boundary layer on a rotating blade……Page 257
7.2 Free vibrations of rotor blades……Page 262
7.3 Forced response of rotor blades……Page 291
7.4 Blade deflections in flight……Page 300
7.5 Basic features of the hingeless rotor……Page 301
8.1 Introduction……Page 314
8.2 The exciting forces……Page 315
8.3 The dynamic design of rotor blades……Page 318
8.4 Main rotor gearbox mounting systems……Page 321
8.5 Dynamic response of the fuselage……Page 325
8.6 Vibration absorbers……Page 328
8.7 Active control of vibration……Page 334
8.8 Vibration at frequencies other than……Page 338
8.9 Measurement of vibration in flight……Page 340
9.1 Introduction……Page 343
9.2 Main rotor pitch-lag instability……Page 344
9.8 Tail rotor pitch–flap–lag instability……Page 0
9.4 Main rotor stall flutter……Page 353
9.5 Main rotor blade weaving……Page 356
9.9 Ground resonance……Page 366
9.10 Air resonance……Page 377
A.1 Euler’s equations……Page 384
A.2 The stability equations……Page 387
A.3 Multiblade summations……Page 389
A.4 The frequency response of a second order system……Page 392
Index……Page 395