I've just gone through this myself, I now have a Brillelli 366GT being built for my 87 inch Yak 54. I just did a WH 85 inch Sukhoi with a LS Pro 50cc, it runs fine and is probably a good sport engine, but it can just hover the Sukhoi, it would be better in a 80 inch size plane, but it was cheap at about $350. If you talking DA money I'd look at the Brillelli, they take about 2 weeks to get.