The 91 4 stroke would probally fly the Sig 1/4 scale cub O.K, and probally scale-like, but 1/5 scale might be a little better choice and offer the abillity to maybe even do a few simple aerobatics especially in the clipped wing version. I have the Sig 1/4 Scale Clipped Wing in the Bones, and it will be powered by a Saito 120 when finished. It won't be a hotrod by any means, but should be ample enough to do a few simple tricks.