I don't get it, the whole thread [X(]...

Why in the trim charts used to trim IMAC planes and Pattern planes they specify to test for aileron differential while doing rolls on a VERTICAL line. If the roll is not axial while going vertically, defferential must be added or removed.

The part I don't get is the use of trim charts is to make the aircraft fly BETTER, not worse [:-].

I think that gravity has nothing to do with aileron differential.