strong- Although not Rossi, I have flown the Byron F16 with Picco 80, and O.S. 61 and 91 engines. I would strongly suggest going with the O.S. 91 as its a sweet low maintenance setup that is more likely to give you less headache/heartaches from my experience. Not saying Rossi's or others wont work well, just that the O.S. is probably the best value for power, parts availability and consistent reliability. In my opinion the O.S. 91 is the engine of choice for the Byron fan...

Cheers