I tried to fly my twist with a 40FP, just for a fun-fly type plane (no 3d/hovering/etc.), Plane was waaaayyy underpowered and there wasn't enough lead in the world to make it balance out right. I tried to fly it anyways..but let me tell ya...trying to fly an underpowered twist with the CG moved back was dang near impossible for me. I could'nt wait to get it back on the ground..a MISERABLE flight..i was doing 3D but it was'nt on purpose!!!...it's on the shelf until I procure a .60 engine for it..