The hole right below where the forward fuel tank attach bracket needs to be drilled and countersunk for a #10 screw. I drilled this out to 3/16″ and then used the #10 countersink cutter to countersink through the sandwich of the side skin, bottom skin, and lower longeron.
Here you can see that the screw will sit perfectly flush after install.
I removed all of the forward clecos and pried the side and bottom skins away from the firewall in preparation for applying the sealant. I also scuffed all of the mating surfaces. The mixing ratio is too precise for me to use the scale I have (only accurate to 1g), so I’m going to need to track down a more accurate scale before I can mix the sealant.
I used a couple of these stubby #40 clecos to keep the side skins spaced away from the firewall.
I also installed the AN3-10A bolts through the rear spar and spacer blocks. Getting these spacer blocks in was more of a pain than I would have expected. It was also tough to get a torque wrench on the nuts on the other side. I ended up having to use a crow-foot wrench on the end of my torque wrench to get them.
