I put a Saito 2.20 four stroke nitro in my 1/3 scale Spacewalker. It flew great. So the 40cc motor should be good also. I had 2 problems with my plane. The wing was very snug fitting into the center section on both sides, and the wing joiner blocks were very soft. The screws that held the wing in place punched small holes in the block and after 5 or 6 flights, the screws no longer held the wings in place. Both were easy to fix, but just a heads up.