[bodywerks]

You are talking about 3 different engine requirements (well, at least two). The 37% will need a 150cc class engine, the compy 2.6 will need a 100cc class engine, and while the 35% is considered a 100cc plane, it is a noticeable bit larger than most of them and a bit heavier. They can be up to the 30 pound range - it will probably hover and pull out, but won't be impressive by any means. It would probably do better with a ZDZ120 or 3W 120. If you can float the dough, my vote is for the 37% Yak. Light, big, relatively cheap, and an awesome flyer. Second bet would be for the 2.6 Yak - it's almost difficult to get them heavier than 27.5 pounds, and even at that weight a good 100cc will yank it around with authority.