Matt I agree that Bryan is the man when it comes to these things. Either he hasn't seen this thread or he is being tight lipped. If it's the latter can't really blame him as he is the one who put in the work. I may send Dick Hanson a line to see what his views may be as he was quite successful designing bipes for some of the TOC guys. I'm interested because I just picked up a new YS 115 for pylon racing but don't really want to have the engine not being used most of the time. I was thinking a 60" 850-900 sq in pattern bipe would be just the ticket.