I am about to embark on constructing a 1/4 scale O-2 Birddog (commonly known as a Cessna 337 Skymaster) from scratch. The Skymaster is an in-line twin engine airplaneone in the front and a pusher at the back of the fuselage. The theory was that in case one engine failed, the plane could be flown on the remaining engine without having to fight with the yaw caused by losing an engine on a wing mounted system.

The wing span will be a few inches over 9 ft. and the plane will be a brick with wings. I can envision lots of hardwood and plywood and servos. I am wondering what to power the plane. I am leaning toward an OS 120AX. That motor will spin a 15" or 16" prop, which would be pretty close to scale. However, I am wondering if two of those would get the thing off the ground. Should I look for a beefier engine? I don't want to lay out $500.00 for two motors only to find out that they are not big enough, not to mention the work needed to rebuild the cowlings and engine mounts. One of my limitations, however, is the availability to find a pusher prop for the rear engine.

Thanks for the help
Tim