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Old 12th Apr 2012, 11:38
  #117 (permalink)  
aerobat77
 
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you really beat it to death gentlemen .

like written above in this particular case you have to split the airframe and the engine. power by definition cannot exist without movement- without movement you can only have a force but not power. so the airframe does not develop any power when the aircraft stands still and no power but anly a force ( e.g the force on the brakes ) is delivered to the airframe by the engine.

but the engine by itself moves ( spins ) and so it of course develops power.

its pretty the same when a diesel locomotive starts to pull a train but its to heavy that it is able to make it move. in this situation the locomotive develops only a force ( on the couplings) but not power.

the diesel engine of the locomotive on the other hand develops power because it spins at a given rpm developing a given torque.

and thats basicly all about this purely theoretic discussion ...

cheers !
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