ORIGINAL: sellaplane
I'm all for advancing the state of the art, but why not go with a gas engine? The fuel is cheap and available everywhere. Has anyone given the Evolution 26cc or Mark 1.80G gasser a try in a pattern plane? The YS's seem to be all the rage for pattern, but personally I've seen a lot of guys fight the things more than I care to do.
This has been debated ad-infinitum. Gas engines are too heavy and don't have the power-to-weight ratio needed for F3A. With a weight limit of 10 lbs, it's difficult to use gas. The YS behaves very well once you get the hang of it. The trouble is, you have to spend the time to get the hang of it :-). Once dialed in, it's the most reliable engine out there not just for F3A but also general sport flying. It can run on zero nitro as well, as long as you use a smaller prop. With zero nitro and 8% oil, the fuel is not that expensive. Add Nitro and you have an incredible powerhouse.
Atul