As I recall, the instructions gave me the choice of 3 levels of dihedral. The most dihedral was for use when you set up the Eagle 2 without ailerons. I expect the high amount of dihedral is required for stability when you turn with rudder only. The middle amount of dihedral was recommended for use with ailerons for beginning pilots, and the least amount was recommended with ailerons for pilots with some experience.

I buildt mine using ailerons with the middle amount of dihedral. In hind sight I think that was a mistake - I should have used the least amount. Mine is more stable than necessary, even for a beginner I think. It will just barely do an outside aileron roll and flying inverted is a real balancing act - it really wants to right itself.