Section 13

  • Wing spar nutplates and countersinking
    Section 13 Wing
    Nov 25, 2020

    When match drilling the J-channels against the wing spar, the plans call out for omitting 4 holes that are near the nutplates on the edge of the lower flange (red arrows in the figure). These were rather hard to see in the drawing, and I totally drilled them, only to realize that once you match drill against the upper flange you'll get 2 holes that are almost but not quite on top of each other. I'll probably consider placing a doubler over those locations once I get to attaching them to the skins, and if that won't work I'll redrill a new J-channel unfortunately.

    For countersinking the fuel tank attach nutplates, I first attempted to follow the recommendations from Vans to use a #30 pilot countersink using the nutplate itself as a guide. I used a standard 3-flute countersink for this, and I can't say it works very well. The pilot still has enough play to cause the countersink to chatter around and without securing the cage this resulted in a really rough countersinking. Doing some research there were seemingly two viable alternatives:

    • Many other builders seem to have manufactured guides that could be cleco'd to the rivet holes of the nutplate and provide a perfect pilot to center the countersink. While this seems the most precise, I had already riveted the nutplates in place.
    • The simpler alternative was to use a single-flute countersink that cuts better and doesn't chatter nearly as much. I decided to try this path first since it was frankly simpler, and ordered a #30 cutter from Cleveland aircraft tool. I think the results turned out pretty well here, a comparison is in the above photo next to their respective countersinks.

    The plans call for a max diameter of the inner and outer countersink holes. I found this pretty hard to measure, and didn't have a piece of dimpled skin to compare, but got as close to the maximum number with a simple ruler as I could without going over.

    Finally, the plans call to spot prime all the countersinks. I've read a whole lot of approaches here from creating a stencil and spraying to using a q-tip. I really wasn't in the mood to spray anything as I only have an LPHV gun and don't have primer in rattle cans, so I chose the q-tip option. I mixed up some P60G2 and dabbed each countersink hole with the q-tip. I can't say the results look beautiful from a paint evenness perspective, but I think it got the job done and didn't take too long.

  • Wing rib damage
    Section 13 Wing
    Nov 25, 2020

    It's never ideal to purchase a subkit and inventory it nearly two years later! The only major discrepancy that I found was that I had two left-halves of the outer skin sheets instead a left and a right. Other than the spars, this was the largest piece in the entire kit, and unfortunately I was well outside of the 30-day window that Vans provides to declare any discrepancies. Vans was kind enough to cover shipping, however, which was probably significant considering the size of the part.

    The only damage I've found so far is what looks like a mispunch on the edge of one of the aft wing ribs, which caused a small tear right at the corner. At first I attempted to drill out the edges of the crack and file it smooth, but it was recommended to just request a new part, and Vans replaced it without any hassle.