Listen to what Ken said. I have used them on planes for years but only on FUN FLY COMPITION PLANES AND FOR COMPITION ONLY. Well usually. I have always slaved them with something else too, usually the elevator one way or another. At the moment I only have one plane set up with them and they are slaved to my elevator so as i add more elevator the flaps/ailerons drop. This set up is on a fun fly plane too, an old HOTS. I only use them to fool around in high winds. I have almost lost this plane on more then one occasion when I forget to turn them off and do a landing. The plane gets close to the ground and drops too much speed and tip stalls, right now, no warning. On a calm day they can bite me quick if I have been fooling with them and forget to turn the switch off. They have there place in flying but they do nothing good for most pilots except create problems. I don't even teach how to set them up to students. If a student decides he just wants to fool with them it's all on there heads, not mine.