polstery,

Your point is well put but I believe most of us already understand that.
And yes somebody did say something about control surfaces, specifically the ailerons. The title of this string is ".46 UCD3D Flutter" and if you read the first three sentences in Robotech's initial post its all about the speed of the air over the ailerons and the resulting flutter. His friend's airspeed was obviously greater going upwind than it was going downwind because flew into the wind at a higher throttle setting.