There is a guy who used to post some info on the G&P here on RCU and on his own website (http://www.frontiernet.net/~rcflyer1/). He had two of them and the had .60 Rossi's in each one turning an APC 11X7 (using an old Tatone pitts muffler instead of a tuned pipe) and said they got going pretty fast. Check out his site to see a few nice pics of his planes.