text: NAVWEPS oo-80~-80 
  APPLICATION OF AERODYNAMICS 
  TO SPECIFIC PROBLEMS OF FLYl,NG 
  
  If 
  the rotor could operate within a wide 
  range of rotor speed, the efficiency and per- 
  formance could be improved. 
  
  With the previous relationships established 
  for the rotor in hovering flight, 
  the effect of 
  forward flight br rotor translation can be con- 
  sidered. With forward flight, a third velocity 
  component, that tif the forward velocity of the 
  helicopter, must be considered in determining 
  the relative wind acting on each rotor blade 
  element. Since the entire rotor moves with the 
  helicopter, 
  the velocity of air passing over 
  each of the elements on the advancfng blade is 
  increased by the forward speed of the heli- 
  copter and the velocity of the air passing over 
  each element of the retreating blade is de- 
  creased by the same amount. This is shown in 
  figure 6.16. 