I know over the years most pattern planes required some aileron differential to get the rolls axial. It has always been explained that the down going aileron needed more or less travel. This really doesn't make sense since when the plane is inverted the effect is opposite. If there was more travel downwards when upright then there would be less travel on the downward aileron when inverted.
If however all that's being done is adjusting the differential so that the fuse rolls straight about it's centerline we are actually compensating for the wing being displaced from the axial centerline and or variations caused by incidence angles. If this is true then a wing at zero incidence close to the axial centerline should end up with close to zero differential and a wing like on a high wing trainer would require a lot of differential.
Am I confused? Better yet, can you straighten out my thinking?
Later,,,basmntdweller