Prop Nut:I havent had any problems with tip stalling or spins.the only thing i did was use a single push rod for the elevator so when we loop it it has a tendacy to roll out because the elevator is so big its twisting more on the side that doesnt have the horn on it.were going to run 2 control rods to cure this.My son and i havent really had the plane slow enough to stall i guess.I land with the throttle,blip it up and down to control airspeed and decent and only use elevator at last minute to flair.
Aero Nut:no i didnt do any mods to the engine.It was the first one i did a ways back before i really started to get into these engines and reading this forum.Then after a few flights the spring on the muffler broke twice so i sold it.a student of mine put it on a Lazy Ace 60-90 size(74-? ws).I havent maidened it yet.