Originally Posted by Fox-composites
Flying upwind or downwind is the same for the model but the pilot perceives the speed differently. It looks like it's flying faster on the downwind leg but it's only the ground speed that is higher.
As model pilots we force the aircraft into a circuit that is relative to the ground and there seems to be a difference between up and downwind flight.
If you have ever watched a free flight model doing circuits and flying off downwind then you will notice the non circular flight pattern but yet the model thinks it just flying in circles.
The model does experience different aerodynamic effects depending on whether or not its flying in a tail wind or head wind, just like a real plane. A tail wind can both make a plane move faster relative to the ground, and reduce lift. A full scale pilot can also tell he/she is moving slower relative to the ground facing a head wind than in a tail wind, both by looking outside, and watching ground speed on the GPS.
"downwind turn" is usually with a tail wind, because runways designated for landing (full scale) are always into the wind because it is much easier to land into a head wind than a tail wind. That said, even if there is 0 wind it is still called a downwind turn as long as you are headed parallel to the runway in the opposite direction as you are intending to land.