Hi Bob, I used one of the 2-56 rods (which I replaced with 4-40) and taped it down to the edge of the wing tip with masking tape. The rod is automatically lined up exactly with the centerline of the wing chord in this way. The rod is extended 2-3 inches beyond the trailing edge of the wing, so that it acts as a reference line for the aileron. I tape the edge of the aileron to the rod when I am setting up the length of the pushrod. Works great.......