Could someone tell me what % of chord a round wing should balance at? I'm thinking of a 30" or 36" wing for a YS .45 that I have. I have some 1" foam handy. I think the engine mount and spine idea used on the PBF is superior to any box fuselage and ply firewall. I dropped my PBF from 50' straight down at full power from a split S and the engine mount did not break. It was a hard smack but I was flying again in 15 minutes. -Tom