There have been many comments about the aileron binding problem on the GP Super Stearman being caused by "geometry" but nobody has identified what the specific problem is. The problem relates to the location of the pivot points for the aileron connecting link. To achieve ideal geometry these pivot points would have to meet two conditions: 1) Both pivot points are the same distance from the hinge line. 2) Both pivot points are on the aileron chord line (inside the aileron!). A modeler could probably achieve the second condition with a little ingenuity, but there is a practical (non-ideal) solution. Note that the manual has you cut the aileron control horn between the second and third hole and attach the clevis to the second hole. This places the pivot points too far from the aileron. Instead cut the control to leave only about 5/16" of the lever arm. Drill a new hole as close to the control horn base as possible while leaving sufficient clearance for the clevis. Mount the control horns equi-distant from the hinge lines. There will still be some slight difference in throw between the upper and lower aileron, but the difference will be minimal and the ailerons won't bind.