Falcon,

Hanger 9 and Horizon say an Evolution gas engine will fit. Check out Horizons Web Site and search for the Twist 150. The spec list will give you the size. Then if you put one in tell me how it went. I only use gas engines in my Giant Warbirds I build to scale. I'm interested in where your going to put the ignition battery and so forth. The 150 Saito is like sticking 10 lbs. of poop in a 5 lb. bag.

Good Luck,

Gibbs