I had an Eagle doing loops because I used Office Depot elastics and the wing lifted at the front, evenly, every time you picked up speed. We would increase speed and immediately do a loop. At level slow flight it was great, but then another loop. It took a little investigating. I found that I push up with my thumbs and hold to the dowel. When there is good resistance it's OK. When there is light resistance, you are asking for the wing to lift/angle of incidence increase. Sig bands are a little tougher than the generics but they vary in quality also.