Drilled the Rear Rib Flange Holes and Created Template for Covering the Old Hole

I managed to get up enough nerve to try to drill the two holes in my custom rear rib flanges of the second 408 rib. I used my 12 inch extension #30 drill bit and tried to apply enough force toward the inner part of each flange go ensure that my edge distance would be maintained. After drilling the holes, I checked the result using my hand-held mirror and a flashlight. The results looked promising.

I could not take off the LE assembly yet because I still have some custom work to do to fill the void created by the old access pane hole that Van's pre-cut into the skin. To begin, I took rough measurements of the major part of the hole, which was a square measuring 4 7/8 inches on all sides. I then grabbed an old file folder and applied those measurements to it:

Then I cut it out, being careful to apply a little extra material but cutting just outside the lines.

Then I removed some of the clecoes holding the new access panel cover plate on the bottom, and slid the paper template up and underneath the panel cover while aligning the other edges with the edges of the LE skin:

Then I traced around the edge of the bottom right side of the new panel cover to transfer the contour of that portion of the panel onto the paper template. Then I removed the template and cut out the area taken up by the new panel cover. This left the rough dimension of the area that needs to be filled after the new panel cover is completely installed.

The next step involved carefully checking the thickness of the new cover plate and trying to find some scrap material of the same thickness. Frankly I am a bit confused, because I think the outer skin is .028 inches thick, and it would stand to reason that if you are filling a hole surrounded by a .028 inch thick skin that you would want to use a piece of metal that was also .028 inches thick. However, when I checked the thickness of the new SafeAir cover plate, it is only .025 inches thick. So I do not understand the mismatch in thicknesses, but it could also be that I am mistaken, and the outer LE skin is also .025 inches thick.

I searched everywhere for some .028 inch scrap aluminum but could not find any. I finally settled on using some .025 inch thick 2024-T3 aluminum from my trim bundle kits for the empennage and wing kits. I taped the template to the metal and drew the outline. This is where I called it a night.

Next steps are to cut out the part from the scrap metal, debur the edges, and start final fitting and trimming it to the old hole. I then need to determine a rivet pattern to use to permanently attach this part to the subskin.Then I need to drill the holes needed for that.

Then comes the all important critical decision of how to cutout the section of the LE skin and trim the remaining portion of the subskin to its final form.Only then will I be ready to dimple all the holes and rivet the whole thing back onto the wing. So still some significant work to do, but its getting done - one day at a time.

KPR...