That makes sense. I hadn't thought it from the fact that ailerons don't really follow the airfoil. I've always known they were a "close enough" approximation, I just never worried about it. (not that I didn't worry about reflex)

Fwiw, I usually measure reflex by putting a straight edge along top of the wing, and measuring the gap at the hinge line. On the airfoil I'm using at the moment, I usually find about a 1/8" reflex on 1.5" ailerons works pretty well. That's a lot of reflex. I'm now wondering if that's an indication that my airfoil has a high pitching moment. (I went over the L/D and Cd vs AOA polars with this airfoil, but just ignored pitching moment). Don't get me wrong though, I like my airfoil.

I'll have to try the power-off trick next time I'm at the field, I never though of that as a test for reflex.

On second thought, it might not help much on my planes, I tend to run a longer tail moment than you do, so the pitching effect of reflex might be different, what do you think?