scalemaster90, I have the GP Super Stearman with a Brillelli 25GT engine. My first flight using a 16 X 8 wood prop was successful, but she seemed a little mushy on take off. I was going to try a 18 X 6 next but didn't get-r-dun. My stearman weighs about 14-3/4 lbs. That is a lot of plane to load on a 25cc gasser. Once airborne the plane flew very well, and I think close to scale. Next summer I will try her again with the 18 X 6 prop and see how she does. A few guy's on this forum told me the 25 was to small. They may be right. I may go to a 40. I will tell you this, the Stearman is not a very big plane and there is not a lot of room inside the cowl. After installing the engine and EI module on the front of the firewall there was n't room for the ign battery, I had to put it on the back side next to the fuel tank. I think I would recommend a 40cc to you. There! I have rambled on enough, hope I have helped some. The Super Stearman is one beautiful airplane, enjoy!.

Regards

Skinny Bob