45cc's may be way too much. This is an 11 lb airplane. It's designed to use a .90 two stroke ( I have the ST G2300 1.4 in mine) or a 1.20 four stroke. - 1.80 would be better. For this aircraft, I would suggest the smaller 26cc or 34cc. But hey, these days guys are putting 1.20 four strokes in .40 size planes.....