ORIGINAL: mjfrederick
ORIGINAL: littlecrankshaf
Try incriminatingly (careful) moving the CG reward. Also, maybe increase flying speed during knife edge. The goal is to lessen the amount of rudder used to maintain knife edge flight. The rudder, by design shape, will impart a roll tendency.
Less rudder application needed...a lesser tendency to roll will be imparted.
Good luck
I think a better solution would be to move the CG forward and add some positive incidence to the wing. Moving the CG aft will just make the aircraft more unstable.
Think about it like this; in knife edge flight the fuselage is the lifting airfoil. It is desirable to have the fuselage airfoil “rotate” easier to produce more lift. A more reward CG will have that effect. A
higher speed with an
easier to rotate fuse will require
less rudder input thereby causing
less roll coupling. Like said previously here, the dihedral is the main factor but tweaking other aspects can have a desired result. On most models, changing the dihedral is not so easy...but changing CG and flight speed is not difficult at all. I have used this technique with great success many times.
Now, if your plane is pitching hard to the gear as well on knife edge this technique will be of little help and your best recourse will be a dihedral adjustment.