check out (www.rcfaq.com)theres pics and explanations on how to convert 2 or 3 engines.look under weedie conversions. also get in touch with (aeronut) here on rcu.he sells a ryans rebel with a 31cc ryobi,all built,covered,engine,arf for about 3-4 hundred dollars i think.other than that go to rcfaqs,do your own on a 31cc ryobi.then put it in a balsa usa 120 size stingray.theres a guy here on rcu that has one and it does evrything in the book.it will just hover for a few swconds then tailslide as to his comments.the stingray is a kit but not hard at all.also try ([email protected]).he has about 30 different converted engines for sale right now.tell him buck from superior sent ya and he will give yu a good deal.