All this is nice to know; I have an old Bud Nosen trainer, the wing bolts on with four 1/4-20 nylon screws. Over time, due to repeated repairs, three or four coats of paint, addition of heavier landing gear and a gas engine, this plane has swollen to 22 pounds. I also increased the wingspan 8 inches (to 96 inches). I was worried whether the bolts could withstand the stresses of loops and rolls to the point that I added functional wing struts to transfer some of the loads to the lower fuse. I still feel better about it, but I guess the blocks that the blind nuts were in would have been pulled out before the screws let go.