Guys,

I think I found another problem with the tips as shown on the Pica plans. W-9, the wing tip, is anchored at the wrong spot at the front. The front edge of the tip should start at W-6A not at W-8. As constructed with W-10 positioning W-9 angle and position against W-8 and W-50, the upward angle of W-9 becomes too steep to get the correct shape. It can be corrected by drawing a straight line from W-6 across W-50 to the high point of the tip and back to the end of the aileron spar in a flat plane. This line will be the center line of the leading edge as it transitions to the wing tip and will require both W-10 and W-50 to be reshaped and the front of W-8 to be repositioned slightly upwards. (P1)

W-8 attaches to the tip bow beyond the end of the aileron spar at the trailing edge of the tip bow and corresponding further out at the leading edge (P2). This would result with W-50 being longer to support W-8.

I believe a better method would be a laminated tip bow about 3/16" -1/4" thick built flat on the board, trimmed to fit to the leading edge at W-6A and the aileron spar end and raised to the proper height. Then W-7 and W-8 can be positioned and filler blocks (or sheeting) can be fitted to simulate the plywood tip sheeting shown in P2. The top front spar can be extended and tapered to support W-7. The front W-12 would need reshaping to support W-8 and the rear W-12 would move outwards slightly but remain the same shape. The W-10s would be made smaller or eliminated.

I will be testing my findings by building a mock wing tip in the next few days.