ORIGINAL: firstplaceaviator
Definitley an airspeed issue. That is all I can tell for sure.
When turning from upwind to downwind, there must be an increase in ground speed in order to maintain level flight.
Say that your plane is flying 60 MPH. The wind is 10 MPH. When flying up wind (level flight) your ground speed will be 50 MPH.
When Flying downwind, your ground speed must increase to 70 MPH to maintain level flight!
A 20 MPH (ground Speed) difference between flying upwind and downwind...... Well, theres your problem!
Doug
???
The wind "carries" the plane. The plane doesn't "know" this, it thinks 60 mph airspeed is what it flies at, regardless of the wind direction.
Adding the wind speed to the airspeed, upwind or downwind, changes the ground speed, but that is totally disconnected from the airplane.
Ground speed is what the pilot sees, but the plane doesn't.
A plane that's trimmed to fly level at 60 mph will fly level at 60 mph in any direction relative to the wind.
Similarly, wind speed doesn't affect the motor.
A motor doesn't know about upwind or downwind.
There's something aerodynamic going on.. the elevator returning to a different position after a commmand is a possible source.