RE: WM Chipmunk question
ST91 is better, YS 110 and TT90 are to heavy.
I am not agree regarding standard servos. On ailerons you would like to have 645MG. Otherwise the aileron servos will strip on hard landings. I have JR 90oz servos on mine and replaced gears three times this year (150 flights). I had once JR 517 servo on aileron and one gear broke in half.