I’ve been stewing over the fit between the fuel tank outboard edges and the inboard leading edge skins; the tank skins stand slightly proud of the leading edges and they “pillow”, or bulge up between the joint plate nutplates when screws are installed. So I started tinkering around with the tank-to-leading edge fit. I used a stick of delrin with a slot cut into one end to edge-roll the tank edges, and although that helped, it wasn’t enough to completely close the gap.

Other builders have had the same problem and pursued a couple of different approaches. My good friend Jim doubled up on the nutplates and screws on the joint plate, and that worked really well. Some folks on VAF recommended shims inserted between the leading edge joint plate and inboard rib. Although that approach require some work to drill out rivets and fit the shims, I decided to try this approach first with the extra nutplate solution as a guaranteed solution if the shims didn’t work.

So I measured the tank-to-LE gaps and the length over which the gap needed to be shimmed, then fabricated a small shim blank of 0.025″ alclad for the right wing and a longer shim blank of 0.032″ alclad for the left. After carefully drilling out all the LE rivets affected by the shims, I slid the shim blanks in place and marked rivet hole locations in them. Drilling, deburring dimpling…and voila, the shims are ready for priming and riveting. Stand by for the completion of this little adventure…

Inboard leading edge shims