I'm not sure how someone can say the conversion engines "aren't worth the time or money". I have a Ryobi in my big 76" Tiger Moth biplane. It was given to me, and you can often find them for free or a few bucks at yard sales, swap meets, small engine shops, etc. It took me about an hour to convert the engine. I also put a Frank Bowman ring in it, raised the exhaust timing to 150 degrees, made a free flowing muffler, and added electronic ignition. It turns an 18 x 6 prop at around 8500 rpms and hauls the big Moth around just great. Level flight loops, Immelman turns, etc., and flies around at less than half throttle except when I am doing aerobatics. Total investment with the ring and ignition system = 80 bucks.

My brother has a very nearly stock Ryobi on his 15 lb. 80 inch wingspan Ryan's Rebel. It turns an 18 x 6 prop at around 7700 rpms and hauls the Rebel around just fine. Will loop from level flight at just over half throttle.

How can they not be worth using????

AV8TOR