Wow, great photos and info. My main purpose is to improve the efficiency of the wing and to help make the wing a little less tip stallee. I'm not really trying to improve the knife edge capability. Best I can remember, the first Sig 231 I had knifed edged pretty good stock. Again, I expect the plane will be a little heavy with a gasser in it. I'm want to experiment with winglets/air dams to see if I can improve the slow flight characteristics of this wing. Most of my big plane flying is around the pattern, touch and go's and basic aerobatics. I purchased the first 231 EX I owned RTF and it came with a Mag G26. That plane flew OK. This plane should be at least 6 ounces lighter than the first one, maybe more. I'll post my winglet test results as soon as I get the plane built.