I have a spare os 50 sxh ringed engine that runs very strong still. I crashed the jr heli it was on and do not plan on fixing it. So I want to take the engine pipe and all the electronics and throw it in another plane. Can I use the heli engine in a plane. It has the drive washer on the shaft to.
If I can what would be an easy to fly, capable of very low stall speeds but can go fast and do aerobatics as well?

Anyone know if it will make a diference?

It will be fine. The only possible problem is the crank shaft is a good bit shorter than the airplane engine so you may have some agrivation fitting a prop, washer, and nut.

it may not throttle as well, heli engines are designed to run at a constant speed.

Yeah true... Anyone want to trade a very strong running OS 50 sxh ringed engine with a revolution muffler and metal throttle arm for an airplane engine with pipe. of equal value? Really a great engine

Don't throw away your SXH, it will run fine on a plane...I have 2 planes with them on and both appear to pull better than the std SX....I put it down to the bigger carbs!

A few things you do need to do thought;
1. Crankshaft is shorter. Either replace with the std SX crankshaft or use a spinner nut....that OS produce.
2. The throttle arm sticks way further out, so you may have a problem with cowl clearance, I cut my throttle arm down and re-tapped the threads. You won't have a problem if you use it on an "open bay" plane.

Good luck!