When I got my Lazy Tiger, had a Saito 30, & a Saito 40, each looking for a home. I decided on the 30. (9500 RPMs on 10% nitro, with 11x5 MAS prop. It flys nice, good level flight speed, loops from level flight, & does mild aerobatics ok, runs for 17 min. at "full tilt, on the supplied tank; BUT, verticle is very limited, &, hard to hold speed on a big loop. Should have put the 40 in. only about an once & a half more weight, & 30% more power! You're gonna love this plane! ........ Geo.K.