mowery1 - Re 26cc engines.... I've owned previous Brillelli versions, and know that his current one is getting very good reviews. His service is above reproach, and his support is as good.

You can read tons of posts about the Zenoah 26, in it's various flavors. Haven't owned one, so can't say.

Evolution and MVVS 26cc'ers are same-same - owned both - to get optimal power and smoothest performance you need a GOOD pipe/header setup. They ** suck ** on mufflers, whether Bisson or Evolution. BTDT.

BCMA is a re-worked SPE ; supposedly without the "SPE" problems. Have had one of those "SPE's. ** IT ** sucked, big time. Couldn't pull itself out a baggie, wouldn't turn a prop I'd bolt on a Yak, for sure.

Again, BCMA's version is getting good press. I know he replaces the carb and igntion, and those are the two things that suck the worst on the SPE.

The "PEAK" 26cc... I currently own the rear-intake. Ran like a REAL p.o.s. until a new ignition and new carb were fitted. Now, it's doing pretty well, turning an APC 17 x 8 around 7900 with it's stock muffler (a VERY loud wrap-around pitts sort of thing).

After all the playing with these that I've done, I'd suggest the Brillelli and the BCMA, in that order. You would be well-served to just "pass" on the others, particularly if you want that beautiful Aeroworks Yak to fly like one.