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Old 17th Apr 2012, 03:14
  #141 (permalink)  
barit1
 
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oggers, please re-read post #144. I made it pretty clear that there are two kinds of efficiency, one for static thrust, and one for propulsive efficiency. Please - when you refer to "efficiency" - make it clear which you are talking about.

According to Hubert C Smith, Associate Professor Emeritus, Penn State, in his “Illustrated Guide to Aerodynamics”:

“actual power available for thrust is obtained by multiplying BHP times propeller efficiency”

“The [amount of power] available is the thp, which is the bhp times propeller efficiency”
Smith here is referring to propulsive efficiency - where the plane is being propelled. Don't use this for the stationary example.
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