haha... this engine seriously amazed me... its specs suggests 3.5 HP @ 17K RPM, the pipe is a match to the engine also from Rossi (UTSM65)... a friend of mine did the engine installation, he had to drill new mount holes for it to fit 45degrees with the pipe underneath the fuselage... when I tached the engine with the 12x6 I was getting 13.3K RPM on ground... I think I might be reaching close to 15K with the 11x8... I will check in the morning... I wanted to sell this plane a while back before even maiden flight... wanted to go GAS... but this plane aint never getting sold