ORIGINAL: LouW
My comment was not intended as proof of anything. It was simply an observation that the required correction is of about the same order of magnitude as would be expected due to slipstream twist alone.
On what basis do you make the assertion that the required correction is of about the same order of magnitude as would be expected due to slipstream twist alone? Have you isolated the twist in a wind tunnel or done a study to determine that the amount of rudder input required to keep the ball centered is due to slipstream twist and no other factor?