have os91fs under the hood,taller lite weight wheels,changed pushrods to golden rods and secured them every 4", couple degrees down thrust ,3 degrees right thrust and away we go, will hover, will go vertical as long as fuel in the tank, knife edge or knife edge loop,do not fly wide open with this set up ,it will flutter. Would I buy this plane again? Nope!!!Way to heavy,poor hardware, flexes to much,sorry wood and glue joints,the covering looks like a prune when the Texas sun shines on it,then when it cools down it gets tight and brittle,also some kind of stickey back covering.
Watch your 6,John