Mr. Scale,

I test flew with 6 ounces of weight installed in the ballast box. The plane acted tail heavy. I increased the ballast weight to twelve ounces and it flew fine. The poster who says I'm wrong with my calculations is using the wrong information. His calculations are based on a biplane with no stagger. The Sterman has positve stagger and you must take this into account. Think of both wings as one assembly. Measure from the leading edge of the top wing to the trailing edge of the bottom wing. This measurement is the chord of both wings combined. Since the chord is constant the math for finding the MAC is simple.
I have a total of twentyseven flights on this airframe since Thursday of this week and it is a pleasure to fly.