11-9-25

When I initially located the fuel tanks, I used a tool a friend of mine had made which sat in the filler neck opening and had a dimple which would mark the underside of the wing skin. I cut the holes in the wing skin off this mark but later had to remove the tanks and remake some retaining straps. I learned that it is VERY hard to re-align the tank into the opening, especially with new straps.

I had no choice but to oversize the openings to permit the filler neck to fit through the skin, however, I wanted to make the whole mess look as good as possible so I created a template to create a 0.4" gap between the filler neck and the wing skin. Upon final installation, I plan to install some fuel resistant foam with a fuel-proof rubber sheet around the filler neck that will push up tightly to the wing skin once the tank is installed again.

I turned my attention to the fuel caps themselves and found the filler neck inner diameter was slightly out of round which I assume was due to welding the neck to the tank. I used a drum sander to very carefully remove material around the inner diameter followed by honing with a 3-leg cylinder hone and cutting oil. I repeated this process until the caps slipped in with minimal resistance yet I could still adjust the cap to properly seal the cap to the tank.

Since I opted to create a tank-to-tank venting system, I chose to install flush fuel caps in lieu of the standard Bearhawk fuel caps. The units I purchased were a bit larger than my tank opening so I had to turn those down a bit on a lathe.