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Old 17th Jan 2018, 23:41
  #13 (permalink)  
PDR1
 
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Originally Posted by joohaan
Lets first agree on the following terminology:
Vy = speed for max rate of climb = speed for max range
This is true, and it is also the minimum total drag speed (maximum excess *power*)

Vx = speed for max angle of climb = max lift over drag = min drag
The bolded part is NOT true. Speed for best climb angle is NOT the minimum drag speed - it's the speed with the greatest excess THRUST. For a jet this may be close to (but still slightly less than) the minimum drag speed because jets have almost constant thrust at all airspeeds. But for anything with a prop the thrust reduces with airspeed, so the best climb angle speed will be significantly LESS than the minimum drag speed.
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