Symmetry in lift generated by aileron
I'm not a pilot, just an enthusiast and a long-time lurker, so please call me out if I'm totally off the wall on this. This is how I handle the symmetry issue:
1. Drag is proportional to net lift, so if lift = x, then drag = px (p is some positive number)
2. In straight flight (no aileron deflection), lift = x and drag = px on both wings
3. An aileron moving generates lift of y in the opposite direction.
Then
4. An aileron moving down generates lift of y. This adds to the lift of the rest of the wing for a total lift of (x + y) and a total drag of p(x + y); therefore drag increases on that side.
5. An aileron moving up generates lift of (-y). This "adds" to the lift of the rest of the wing for a total lift of (x - y), and a total drag of p(x - y); therefore drag decreases on that side.
6. Since there is more drag on the aileron-down side than the aileron-up side, the airplane will want to yaw towards the aileron-down side, hence adverse yaw that must be compensated for with rudder movement.
Is this more or less accurate?