skillet92 - the little Evo has roller bearings, but due to the size of the bearing, more oil is recommended to keep it happy. Not to mention they're turning it up at rpm levels I wouldn't dare take a bigger engine. Same thing regarding the 20cc engines and their suggested 32:1 vs. the 30cc and larger where about anything goes.

Interesting point regarding the size of the op's plane, what it would take to power it with elec. and the associated dangers vs. a park flyer? I think you could get past the safety issues, but I always liked the bigger trainers for their better manners, especially on days when wind is an issue? There's also the thought regarding the fact the larger size is more easily seen? If that's a factor, that idea alone might sway my vote towards the baby Evo. -Al