5.0 Hours -
The first thing I did today was to drill the forward flange of the z-brackets using the tank baffle as a guide. All of the holes were drilled to 1/8”.
The remaining z-brackets were drilled to 1/8" using the baffle as a guide.
Once the z-brackets were drilled, I had to reattach both the leading edge and the rest of the fuel tank to the wing. Once everything was back in place, I double checked the fit again and then drilled holes in the leading edge joint plate that will later receive nutplates for attaching the tank. The holes in the tank skin were used as a guide to drill these to #19.
I had to re-assemble the wing...again. This time, it was so I could drill the joint plate.
The gap between the fuel tank and leading edge skins still looks great. The joint plate was drilled to #19 where screws will attach the fuel tank.
I then took the tank off the wing, once again, and placed it into the cradle. As soon as I took the tank off, I was happy to see that all of the holes in the forward flange of the z-brackets were spaced properly. All of the skin to rib/baffle holes were drilled to #40, and the holes that receive screws for attaching the tank to the spar were enlarged to #19.
After tanking the fuel tank off the wing, I was happy to see that all the z-brackets were drilled appropriately.
With the left tank back in the cradle, I final drilled all the holes except those for the stiffeners.
The skin to baffle holes have to be countersunk in order to facilitate sealing and final assembly. Normally, parts as thin as these would be dimpled, but dimples would make it difficult to slide the baffle into place during final assembly (though I know some people do it this way). The skin was countersunk with the baffle in place so that the countersink would have a bit thicker material to help it stay centered. Once again, I did all the countersinking with an electric drill…it just seems to chatter less than my air drill.
The holes that are used to attach the tank skin to the baffle get countersunk. Normally, these would be dimpled, but that would make it difficult to insert the baffle during final assembly.
Finally, I started working on the fuel tank stiffeners (T-711A through D). As with stiffeners in the empennage, these came as long stock that had notches to mark where each stiffener begins/ends. I cut the stiffeners apart using my band saw, and then started to work on finishing the edges with my Scotchbrite wheel. I was able to finish about half of them before deciding to call it a night.
I seperated all of the stiffeners and started finishing the edges.
