While I wait for a replacement main rib on my right wing, I went forward with making the flaps. Once you sort out the proper orientation of the ribs, its pretty straightforward to assemble. All the skins were predrilled so it was a matter of putting the flap spar onto the bottom skin. Look through the predrilled holes to find your rivet line which you marked on the spar flanges (top flange and bottom flange. Line up the straight (square) side of the flap skin with the spar flange end and clamp it in place. Fit the inner ribs into place and looking through the predrilled holes in the flap spar, drill the forward end flanges of the inner ribs to the flap spar #30 and cleco. Seeing the rivet line through the flap spar lengthwise holes, match drill through the skin into the spar using #41 for now. Then, flip the flap over and drill through the predrilled holes in the bottom skin into all the inner rib flanges and cleco. Fit the end ribs in place and repeat the process. On one end of the spar the spar web slopes inward 1/8 inch narrower at the top vs the bottom. When you match up the rib, be sure to slant the rib so it aligns with the slanted spar end. Also, then measure 1 5/8" in from outermost rear corner of the flap bottom skin to the web of the outer rib and once located at that measurement, clamp it and then drill it for the skin/rib holes.
Just need to match drill the top skin to the top of the spar...
The flush end of the flap. Disregard writing. I swapped parts..
