Ref.

"forgive me, but my question is this... unless you fly the EXACT same model with the stab in two different places.... how can you really tell if it is making a difference.. as two models of the same plane can fly quite differently due to the several hundred other things that could be a hare of here, a scosh there??

Honest question... how do you "KNOW" it made a difference? "

The way I found out about this condition was flying my CAP's, including a 321 EX. They all exhibited a wicked push to the canopy in four-point rolls and knife-edges. When a plane does not "work", out comes the knife or saw.

For roll-couple I used to increase or decrease the dihedral. For elevator problems the rule of thumb was lower the stab for a push and raise for a pull. How much is a guessing came of trial and error. Also it is not a simple action and result because other things can be made worse such as pulling or pushing to the canopy in up and down lines. After 50 years of modeling you get good at guessing!

As regards the Great Planes CAP 232, mine only needed a few % of up and no roll correction. It was by far the best CAP I have ever flown in many departments. Also I have never built an ARF as good as this one. Said another way, I didn't modify it. Usually I do something. Not on this one. I did fit a soft-mount but that's another story.

Regards,

Eric.