Ok I think I found the reason for the flutter problem. My buddy and I spent the evening finishing up my Bobcat (also with an OS55) and putting the new ailerons on my U can Do. We took the old one, the ones that fluttered so badly, and cut the monocote off of them. What a shock! The built up section where the control horns attach, weren't glued! Even at the joiner points, there were major "dry" spots. Also several of the stringers that ran across the aileron were of such soft balsa that simple finger pressure was enough to damage them. Let me hasten to add we aren't talking about much pressure. The new ones are much stiffer, and we made sure that we wicked up plenty of CA (even drilled a few extra ports for us to dribble CA into) and by the time we mounted the new control horns, the edges where they were to mount were hard as iron! Tomorrow we fly it again, and will maiden the BobCat as well. Wish me luck.

Bruce