Applied about 50% rudder to fly knife edge, applied remaining 50% and no noticable increase in angle. Is this my plane, wrong prop choice, etc? Rudder servo is a Tower TS-67 (?) with around 90oz/in at 6.0v. Plane is a Sig 1/4 scale Cap. Is there some 'trick' to getting it to go correctly? The only reason I'm not immediately suspecting the rudder is that I had a smaller cap that I let my instructor preflight a while ago and he did a knife edge loop right off the bat and I was never able to do so. Perhaps I'm not getting the sticks right, the entry, etc? Any help appreciated.