G'day A friend of mine used to fly a plane with a heli engine. It was not modified in any way but you may need a prop driver and prop washer and nut from a similar plane engine. Heli engine are usually designed to run at high revs constantly and so you may need to experiment with props to find a suitable one. For a 30 size engine a 9 x 6 would probably be a reasonable starting place - for a 40, a 10 x 6. Heli engines usually have larger heads for better cooling but my friend did not modify the head of his engine at all. The heli muffler may also not be the right shape to use in a plane.

Why not sell the helicopter as parts or whole and use the money to buy a more suitable engine? I think you can sell things here or there are always other ways.

All the best

Mike from Oz