Originally Posted by yawningdog
Well?...What are the control inputs then, or is it a big secret? I'd like to try it out with my little radio controlled plane!
Invariably, combinations of full yaw, pitch and roll at very low airspeeds and high power settings have the desired effect.
An excellent reference is the English translation of Xavier de Lapparent's "The Aerobatic Four Minute Freestyle", which details the basic types of tumble.
Failing that, have your model draw a vertical line (upwards!) and as the speed decays put the stick in one corner and the rudder in the other and see what happens.