Hey there

I am the guy from dream-rc-airplanes and have done several chippers for customers. I looked back in my files and I find the wings were set at 0 to the datum and the stabs were also 0. The last one did change airfoils to the tip and it flew with no elevator trim with the wing at 0 degrees and 1.5 of washout in the tips.

My thoughts were that the washout was only outboard of the MAC (mean aerodynamic cord) and that changed the lift of the wing in that area. Since the full scale was so aerobatic, Art put in the washout to be sure he did not tip stall and get a wild rotation at slow speeds.

The gas model stalled straight as could be and did not show any evidence of needing incidence in the wing. I flew it straight done at idle and it did not pull out of tuck so I am thinking the setup was just about right

Hope this info helps