I didnt get back here quick enough with my other idea. Do you still have the punchouts from the ribs? If so you could use it as a pattern to mark the new opening, and use it to fill in the original, then re-cut it right on the marks from the pattern. I looked at my airfoil shape and didnt see any difference. I looked in the manual to see if they specified a proper orientation for the ribs and the only one they specify is the #1 due to the servo openings. Hope this helps.