Weeks 27-30: Left wing wrap-up, right fuel tank

Since the last update, I have finished installing the solid rivets in the left wing rear skin support. Once that was done, I completed the left flap. I did not see any interference with the rivets, so I am very pleased with how this turned out. Now the next step will be to replace the pulled rivets on the right wing rear skin support to match the left one.

I went through the same process for the left flap per the manual with checking the alignment for every set of holes. I didn't run into any alignment issues, and I believe the final result is acceptable. Since I didn't have any interference issues with the rivets, I completed the riveting of the left flap.

I also finished attaching the left wing-tip with nut-plates and screws. This was much easier this go around. Now the wing tip is installed for (what should be) the last time, with the light wired up to the harness.

After a vacation break, then a delay waiting for help moving the left wing to the stand and getting the right wing back on the table I was ready to start attempt #2 on the right fuel tank. I unwrapped my replacement rear channel and discovered it is the one intended for the larger capacity fuel tank that is now standard. After the initial dismay expecting a significant delay waiting for the correct part, I looked at it closer and determined I might be able to modify the longer part to work.

Since both fuel tanks match the wing geometry (the larger one just goes one rib farther), I figured the taper of that part should be the same as the one I need. I verified this by clecoing it in place temporarily. All of the fuel tank rib holes lined up correctly, except for the outboard one at the end of the tank. On that one the existing holes were past the point I would need to cut the longer part down to work. I also installed some cleco's into the channel through the skin. Fortunately all of these seemed to line up as well.

I confirmed with the Sling technical support group that the parts were identical up to the end of the smaller tank and they provided some dimensions to help with the modification process. Ultimately I decided to cleco the left tank rear channel to the longer right tank part and use it as a guide. The two parts should be mirror images of each other, so this was the easiest way to get it to match. After trimming the part down with a dremel, I notched the corners to match the correct part and drilled the holes for the end rib. The end result is a part that should be very close to a perfect replacement for the original.

Once that part was correctly modified, I cleaned up the inside of the tank as much as possible, then put extra fuel tank sealant around all the joints and rivets. I did a thorough inspection after it had a chance to dry, then permanently attached the rear channel with a healthy amount of sealant. I tried to make sure all the rivets going through the skin had plenty of sealant under the rivet head.

Unlike my first attempt I am going to give the tank plenty of time for the sealant to cure before I test it. I finished sealing it on Monday, so I am planning to test it again on Sunday at the earliest. In the mean-time I am going to work on replacing the pulled rivets in the rear skin support with solid ones and completing the right flap assembly.