ORIGINAL: red head
It isn't really the dive that hurts, it's the pull out at the bottom that usually folds the wings. Gentle movements work fine. Of course I guess if you could dive it and get it fast enough that could also do some damage.
When I was flying mine there were about 4 other ones in the club and I was the only one that survived because I had reinforced my wing a lot, they didn't and tried to do the same things I did and every one folded their wings. One other one lasted a long time because he flew it pretty calm.
I wouldn't normally keep harping on this subject but I know what it takes to build a Butterfly and I hate to see folks spend that much time and wipe it out real quick. Either reinforce it or keep the flying slow, smooth and easy !!!!
I disagree! I think it is speed which the airframe can't handle. Speed is built up in the dive and speed causes the wing to flutter. My guess is most of the failures which have occurred to this airplane were caused by flutter. The wing lacks torsional rigidity, as a I stated earlier.
I also disagree with not using epoxy. Epoxy has strength which white glue lacks and should be used wherever it is recommended by the manufacturer! Also, if you really want to build light, use CA. Some people react to CA and likely should stay away from using it. However, for the lightness of the build, nothing beats CA.
Buzzard Bait, I found your post could be confused and felt the need to clairfy that epoxy absolutely needs to be used in certain instances, such as the dihedral reinforcements at the polyhedral and center section joiner pin and tubes.