Helicopter Aerodynamics Volume IIThis is a collection of the Ray Prouty's columns in Rotor and Wing and American Helicopter Society's Vertiflite magazine from 1992 to 2004. |
Contents
Chapter 1 | 1 |
Maximum Speed | 7 |
Bucket Speed | 9 |
Maximum Thrust | 11 |
Feathering Equals Flapping | 15 |
The Helicopter in Trim | 19 |
Airfoil Aerodynamics | 21 |
Airfoils The Third Generation | 29 |
NeverExceed Speeds | 171 |
Speed Stability | 177 |
Center Of Gravity Position | 181 |
Dutch RollDesign Compromises | 185 |
Torque Change with Roll | 187 |
Why Hovering Helicopters Are Unstable | 191 |
Damping Is Good | 195 |
Settling With PowerAn Explanation | 197 |
Center of Pressure or Aerodynamic Center? | 31 |
Dynamic Lift | 33 |
The Gurney Flap | 37 |
The Compound Helicopter | 43 |
The Truth About Propellers | 47 |
The Truth About Wings | 51 |
Tandem Helicopter Trim | 55 |
Coaxial Helicopters | 57 |
The BERP Tip | 63 |
The Scissors Rotor | 69 |
A Tiltrotor Challenge | 73 |
Tiltrotor Download in Hover | 75 |
FanInFin | 79 |
NOTAR | 83 |
Vertical Tail Surfaces for NOTAR | 89 |
Horizontal Tail Trouble | 93 |
How the Apache Got Its Tail | 97 |
The History of Cyclic Pitch | 103 |
The Hover Problem | 107 |
Vortex Rings in the Hover | 111 |
HoverAn Uncertain Flight Condition | 115 |
Flying High | 119 |
Managing Energy | 125 |
Rotor Outwash | 129 |
Helicopters and Ride Quality | 131 |
Reduced Visibility Effects | 133 |
Flight Testing to New Standards | 137 |
The Sidearm Controller | 143 |
The Downwind Turn | 147 |
A Tragic Accident | 151 |
A New Look At Dynamic Rollover | 153 |
Tail Rotor Failures | 155 |
Translational Lift | 159 |
Unrealistic Practice Autorotations | 161 |
Autorotation Concerns | 163 |
Maximum Descent Angle | 165 |
An Autorotational Paradox | 167 |
Rotary Wing Aircraft In Steep Descents | 201 |
TailRotor and MainRotor Interactions | 205 |
Computers And Rotor Aerodynamics | 211 |
TwoG Charlie | 213 |
Floquet Theory | 215 |
Numbers And Helicopters | 217 |
Tip Loss | 225 |
Root Stall | 231 |
Coriolis Effects | 235 |
Angle Of Attack and Lift Distribution | 239 |
Torque Distribution On Two Rotors | 243 |
Torque Distribution In Autorotation | 247 |
Slots And Flaps On Rotor Blades | 249 |
CirculationControl Blades | 251 |
The JetFlap Rotor | 255 |
Wind Tunnel Wall Corrections | 257 |
A Wind Tunnel Dilemma | 261 |
New Tail End for the MD 600 | 265 |
Mechanical Blade Couplings | 269 |
The Order of the Hinges | 273 |
CrossCoupling Mystery | 277 |
Some Coupling Considerations | 281 |
Noise Regulations | 283 |
Designing Quiet Helicopters | 289 |
BladeVortex Interaction | 299 |
Vibration Prediction Is Difficult | 303 |
A Tale of Luck in Helicopter Design | 307 |
Flutter | 309 |
Gs Versus IPSs | 313 |
Vibration Absorbers | 315 |
Smart Materials And Helicopters | 319 |
Calming The Rotor | 323 |
Gerard Herrick and his HV2A | 333 |
The Sikorsky R6 | 339 |
Helicopters in China | 343 |
Ray Proutys Personal Library | 349 |
Common terms and phrases
aerodynamic aerodynamicists aircraft airfoil airplane airspeed altitude angle of attack Apache autogyro autorotation Bell BERP Black Hawk blade area boundary layer center of gravity coefficient collective pitch configuration control system cyclic pitch decrease developed disc loading drag Dutch roll dynamic effect Eurocopter fenestron flapping hinge flight conditions flight test flow flying force forward flight forward speed frequency fuselage gross weight Gurney Flap gyroplane helicopter rotor higher hover performance increase induced velocity installed knots lift Mach number main rotor maneuver MDHC noise pilot pitching moment power required pressure problem produce propeller rate of descent ratio reduced retreating side Reynolds number roll rotation rotor blades rotor speed shaft shown in Figure shows Sikorsky Sikorsky S-76 surface swashplate tail boom tail rotor thrust tip speed tip speed ratio tip vortices torque trailing edge trim vibration wake wind tunnel wind tunnel tests wing