akflyer-Seems like we're narrowing it down to a possible incidence problem. The kit I got from Ohio had a wing jig with it that gave you less incidence at the outside compared to the wing root (Better tip stall protection). Maybe if you take measurements at both wings (root and tip) plus the stabilizer mentioned before it might give you a clue to this frustrating problem.

On the cowl- I've had trouble in the past with engine cooling on scale planes. My T-28, with a huge front opening entrance, overheated due to very little exit. So on this Sukhoi I cut out only a small opening directly in front of the cylinders. Then I cut out all the square exit openings where the louvers go plus another exit out the aft bottom where it doesn't show. Haven't run it yet but I hope this does the trick.

Let us know how it goes. JD