text: Two types of stability are important in the 
  (1) angle of attack stability and (2) 
  rotor: 
  velocity stability. 
  the 
  relative wind velocity, angle of attack, and 
  lift on each blade of the rotor is the same. If 
  the rotor is displaced through some angle, no 
  changes in forces result. Therefore, the rotor 
  has neutral angle of attack stability when 
  hovering. However, 
  flight, an 
  in 
  increase in rotor angle of attack increases the 
  lift on the advancing blade more than on the 
  
  In hovering  flight 
  
  forward 
  
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