Well I have build maybe 10 different foamies from depron and other materials. The power option I usually deal with is around 450 ,550size electric motors on 3 or 4 cells. I fly high and low wings almost 2 or 3 times a week. I have a p51 mustang with air brakes and flaps and also a Cessna 182 with flaps.so I was pretty confident about the Phoenix strega. But everybody was talking about os 40 being under powered so I just bought a magnum xl 52 4 stroke. Im going to install it on mustang and maybe ask for some help for the first flight.