ORIGINAL: Nathan King
I would strongly recommend against using a petrol engine on this airframe.
And I would strongly recommend it. Mine flies with a Fuji 50EI, and does so well. Another at our club flies with a Brisson of similar (not sure which one) size and performs fantastic. Why anyone underpowers airplanes, and then watches them drag around the sky without the power to perform is unknown to me, but none of my business. When they make those unwarranted suggestions to others though, I'll object.
When the airframe is large enough, and can be reinforced in the critical areas (within reason) to accept gas, it's a great way to go. Efficient, powerful, and clean.