I think what we are talking about is a compromised tradeoff between stiffness and lightness. They are both good, however, they are very ellusive as a mutal goal. So what is better... a stiffer airframe and wing that will be a good motor mount and will not flex during the highest flightloads or a lighter, but maybe more flexible airframe that gets up to speed a bit faster? I don't even try to build a 3.5 LB 428. I prefer a stiffer fuse and wing. I don't even use contest grade balsa anymore although I do have Lone Star hand select the weight woods I want. The only way I actively cut weight is to strictly limit use of glue and paints and carefully weighing the materials before use so I have the correct weight wood and other materials where it is needed. I generally stick to 7-8 LB balsa for the fuse and wing sheeting. My planes generally come out several onces heavy... but so do those $500 composites. IMHO.


Dan