I know you said you want a gas or large engine such as a radial, but I cannot expound enough on how nice the Proctor Jenny is. Almost no sanding, and on this model picutred here, the extras I had to buy were the wire wheels, covering, engine and fuel tank. That Laser they sell is just cool as heck, runs best on no nitro, no tank pressure.
Anyhow the bipe flys really sweet and looks so cool in the air. Here is a pic, can't figure out how to load them here
http://www.scalerchelis.com/gallery/...ny9_15_05_006A
Jack