[Freddy Warbird]

With aerobatic aircraft, I like to think of my flying surfaces like an automoblies wheel alignment. If my control surfaces are not neutral with my appendages in neutral flight, and the plane is not flying straight @ 0, 45, 90, etc...whether inverted, or right side up, something is out of alignment, or out of adjustment. In order for an automoble to track straight down the road, all of it's suspension angles need to be in the correct position. Camber, Caster, Toe, S.A.I, T.O.O.T, all need to be correct, or one will be compensating with the steering wheel all the time while driving down the road. With Too much positive Caster, tracking is very stable, but steering is very difficult. Too much negative Caster, steering is very easy, but stability is lost. If Camber angles are off, either too positive, or negative, the car will pull, or push "drift". The tires will wear out prematurely. All cars require some positive, and negative adjustment to keep the car tracking straight down the road. If one, or more of these angles can't be corrected with factory adjustments, parts need to be replaced. Warped sufaces, incidence, CG, lateral balance, differential, Trustline, trim etc.. are no different. True, some planes require some negative elevator while inverted to keep the plane tracking straight even if the plane is set up correctly. -That- is in their design. On the other hand, other planes feel very neutral inverted. Cars are -no- different. One year, make, and model may need -2 degrees of camber, and +1 1/2 degrees of positive Caster on the right side for correct alignment, while another may not. The point is, all four wheels on the car need to be adjusted for the road, so the car "tracks" straight, and won't prematurely wear out tires. If your plane needs "excess" negative elevator to fly straight/ level while inverted in the sky, check your alignment angles, and CG. If your plane is drifting to the left, or right in a 90 degree upline, check the trustline. -Measure!- Don't guess!- Is the incidence between the main wing, and the horizontial stab correct? No ammount of CG ajustment is going to correct that if its off.