Download Helicopter Design Methodology by Andrew T. Bellocchio to Learn DRIVE SYSTEM DESIGN METHODOLOGY FOR A SINGLE MAIN ROTOR HEAVY LIFT HELICOPTER.

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Table of Contents-

ACKNOWLEDGEMENTS ............................................................................................IV

LIST OF TABLES ...........................................................................................................IX

LIST OF FIGURES ........................................................................................................XII

LIST OF SYMBOLS.......................................................................................................XV

SUMMARY .................................................................................................................. XXII

SCOPE ............................................................................................................................... 1

MOTIVATION ................................................................................................................. 3
Need for a Joint Heavy Lift Helicopter .......................................................................... 3
Square Cube Law............................................................................................................ 5
The Importance of Heavy Lift Drive Systems................................................................ 9

JHL BASELINE.............................................................................................................. 11
Government Furnished Baseline................................................................................... 11
Design Excursions ........................................................................................................ 15
Design Space................................................................................................................. 17

ASSUMPTIONS.............................................................................................................. 19

METHODOLOGY ......................................................................................................... 20
Design Process.............................................................................................................. 20
Methodology for the JHL ............................................................................................. 22

WEIGHT ESTIMATION............................................................................................... 25
Solid Rotor Volume Method......................................................................................... 25
Simple Gear Mesh..................................................................................................... 26
Composite Gear Systems .......................................................................................... 29
Boeing-Vertol Weight Formulae .................................................................................. 31
RTL Weight Formulae.................................................................................................. 32

GEARING ....................................................................................................................... 34
Gear Fundamentals ....................................................................................................... 34
Gear Failure Modes ...................................................................................................... 37
Gear Types and Functions ............................................................................................ 41
Spur Gears in Helicopter Transmissions................................................................... 42
Helical Gears in Helicopter Transmissions............................................................... 43
Bevel Gears in Helicopter Transmissions................................................................. 44
Face Gears in Helicopter Transmissions................................................................... 47
Rating Spur and Helical Gears...................................................................................... 49
Spur Gear Force Analysis ......................................................................................... 50
Helical Gear Force Analysis ..................................................................................... 52
Contact Stress............................................................................................................ 53
Allowable Contact Stress.......................................................................................... 57
Bending Stress .......................................................................................................... 62
Allowable Bending Stress......................................................................................... 65
Spur and Helical Gear Materials............................................................................... 66
Scuffing Hazard ........................................................................................................ 68
Rating Bevel Gears ....................................................................................................... 73
Bevel Gear Force Analysis ....................................................................................... 73
Contact Stress............................................................................................................ 76
Allowable Contact Stress.......................................................................................... 78
Bending Stress .......................................................................................................... 80
Allowable Bending Stress......................................................................................... 82
Bevel Gear Materials ................................................................................................ 82
Scuffing Hazard ........................................................................................................ 85

SHAFTING...................................................................................................................... 86
Simplified Shafting Model............................................................................................ 86
Margin of Safety ........................................................................................................... 89
Vibratory Bending Stress.......................................................................................... 90
Axial Tension Stress ................................................................................................. 91
Torsional shear stress................................................................................................ 92
Critical Speeds .............................................................................................................. 93
Nonuniform Shafts.................................................................................................... 94
Uniform Shafts.......................................................................................................... 97
Shaft Materials.............................................................................................................. 97

GEARBOX COOLING ................................................................................................ 100

TRADITIONAL PLANETARY MODEL .................................................................. 103
Drive Arrangement ..................................................................................................... 105
Planetary Main Gearbox ............................................................................................. 107
Planetary Drive Modeling........................................................................................... 108
Weight Estimation Results.......................................................................................... 110

SPLIT TORQUE MODEL........................................................................................... 112
Drive Arrangement ..................................................................................................... 113
Torque Split Drive Modeling...................................................................................... 115
Weight Estimation Results.......................................................................................... 116

RESPONSE SURFACE METHODOLOGY.............................................................. 120
Overview..................................................................................................................... 120
Planetary Drive RSM.................................................................................................. 121
Split Torque Drive RSM............................................................................................. 124

CONCLUSIONS ........................................................................................................... 129

FUTURE WORK .......................................................................................................... 132

APPENDIX A: JHL SUPPLEMENTAL PACKAGE EXTRACTS ........................ 134

APPENDIX B: SPUR-HELICAL GEAR RATING CALCULATIONS ................. 140
Spur-Helical Gear Summary....................................................................................... 141
User Inputs and Selections.......................................................................................... 143
AGMA Stress Equations............................................................................................. 145
Scuffing (Scoring) Summary ...................................................................................... 150
Lubrication Analysis................................................................................................... 155
Material Properties...................................................................................................... 156
Bending Stress Geometry Factor ................................................................................ 158

APPENDIX C: BEVEL GEAR RATING CALCULATIONS.................................. 162
Bevel Gear Summary.................................................................................................. 163
User Inputs and Selections.......................................................................................... 164
AGMA Stress Equations............................................................................................. 165
Force Analysis ............................................................................................................ 169
Bevel Gear Geometry ................................................................................................. 170
Material Properties...................................................................................................... 173
Bending Strength Geometry Factor ............................................................................ 174
Pitting Resistance Geometry Factor ........................................................................... 179

APPENDIX C: SHAFT DESIGN CALCULATIONS............................................... 182
Summary of Results.................................................................................................... 183
User Inputs and Selections.......................................................................................... 184
Margin of Safety ......................................................................................................... 185
Critical Speed (Uniform Shaft)................................................................................... 187
Critical Speed (Nonuniform Shaft)............................................................................. 189
Total Load and Moments............................................................................................ 194
Material Properties...................................................................................................... 195

APPENDIX D: PLANETARY DRIVE CALCULATIONS...................................... 196
Design Calculations .................................................................................................... 197
Weight Equations........................................................................................................ 201
Modified Solid Rotor Volume Weight Estimation..................................................... 202
Force Feed Oil Cooling............................................................................................... 204
Minimum Weight Solution ......................................................................................... 205

APPENDIX E: SPLIT TORQUE DRIVE CALCULATIONS ................................. 206
Design Calculations .................................................................................................... 207
Weight Equations........................................................................................................ 210
Modified Solid Rotor Volume Weight Estimation..................................................... 211

APPENDIX F: MODEL FIT FOR PLANETARY DRIVE....................................... 212
APPENDIX G: MODEL FIT FOR SPLIT TORQUE DRIVE ................................. 216
REFERENCES.............................................................................................................. 220