Hi Charlie P.
You mentioned that a snap roll on a sporty model pulls about 10Gs. Is that a guess on your part or is that a good figure? I insist that all of my planes do snap rolls, and I reinforce them accordingly. Frequently the snap rolls are very violent. I am only guessing on what reinforcement is needed. I do not recall ever having a failure from a violent snap roll. I have wondered what kinds of stresses are involved in my snap rolls. Without some strain guages here and there the only way to know if a wing is strong enough is to have one snap off. I recently saw an ARF J3-Cub break a wing in a snap roll. I have a 72 inch wing span SPAD J3-Cub with a .46OS engine, that I designed, built and snap roll. I have not made violent snaps with it yet. I need to work up my nerve. I'm still a little afraid of it since I have had 3-4 bad crashes with it. It will soon do a violent snap roll or come down in pieces. I would appreciate learning anything else technical from you on stresses during manuevers. Does the average full speed loop pull more than 10Gs? Thanks for your help.