I fly mostly 1/2A to .15 sized stuff and have planes that will fly from here to JUPITER [straight up] with no working rudder, and zero-zero on the engine. Same goes with my .32 to .50 powered speed planes turning 8" and under props, no engine thrust. Hey for that matter, zero-zero with my Q-500 PREDATOR. Once you get into the 10, 11, 12" and larger prop zone, then right thrust is definitely welcome.You will see down thrust needed when you have a very low thrust line, or up thrust handy if you have an engine mounted high relative to where the wing is at.