Originally Posted by erkq
Uh... the headwind makes it go slower for a given power output, so it takes more Whr's to travel a given distance, but it's delivered at the same rate for a given airspeed. The plane knows nothing of the air's velocity that it's flying in. Unless, of course, you're talking adding power to keep ground speed constant. Then, you're correct.
But that's just it. I ain't testin' the dumb ol' plane, I'm testing its drivetrain.
(Which KNOWS the difference in upwind vs downwind requirements, right?)