RE: CAn I use a rc car motor in a combat plane
Probably no. The engine workings are basically identical to RC plane engines (except the large cooling head on a car motor, which is no big deal.) However, you probably won't have the right surface to mount the prop not to mention the crank might be a bit short. If you can find a thrust washer that will fit the engine, then it might be useable. The thrust washer is a must to keep load off the bearing or case housing. While it may "work" to jamb the prop between two nuts which is what I think you ment, I'd consider this extremely dangerous. Without the thrust washer, you are much better of just getting a RC engine that was designed for aircraft. Cheers