Right leading edge and fuel tank prep

TLDR

• Installed right leading edge
• Squeezed right trailing edge solid rivets (minus a few)
• Deburred and dimpled all fuel tank ribs
• Prepared right fuel tank skin

Right leading edge

Last week I found some time to re-install the right leading edge skin. Since this is the second time I’ve done it, the process went through quickly.

Work in progress installing the leading edge skin

Trailing edge solid rivets

I gave up using the penumatic squeezer, and went back to the hand squeezer with a few changes.

1. Instead of 3 inch yoke, I switched to a 2 inch yoke for better control and less flex.
2. instead of -4 rivets, I swtiched to -3 rivets. I still think -3 is a little too short, but everyone else is using -3 on Sling Builder group, as is recommended by Sling Technical.

With some more practice, the final result was not too bad. There were a few places where my squeezer cannot reach, so I will just use pop rivet in these spots, not a big deal.

Solid rivet top view

Solid rivet bottom view

Fuel tank

Then I spent most of this week working on fuel tank preparation. I started with ribs on both tanks, and eventually focused on right tank.

Rivnuts

The parts were packaged very well. All ribs are in the same bag. I thought it would be quicker to clean/debur/dimple all of them instead of waiting for left tank. So that’s what I did.

Some of the parts before prepping

I first installed a bunch of M4 rivnuts on rib 2. This step does not need sealant yet, so I just got it done so I don’t have to worry about it later on.

Rivnuts installed on both rib 2s

Plastic cover

Step 2, extremely exhausting - peeling off plastic on all the parts. 1 hour later, the job is done.

Plastic off, it’s not too bad to peal them off from ribs

It’s a different story for the skin. This MF took me an hour. Some cursing were involved

Dimpling

All ribs and the skin needed to be dimpled. Most of the holes were 3.2mm with one row on the trailing edge of the skin being 4.0mm. Nothing too difficult, it took some patience to juggle the skin as it’s pretty large.

Dimple in progress

I used a sawhorse with foam blocks to support the skin while dimpling

Builidng a fuel tank jig

As I was dimpling the skin, the skin shook a lot with my unstable hands. I decided to build a jig to provide supoprt.

The process is not difficult at all. And it required a lot less precision than I expected.

I laid the template drawing on a 3/4” MDF board and traced the shape, then used a saw to cut the pieces out. Then I screwed them together between 2 beams (2x4 by 1572mm as instructed by the template).

Quick and dirty tank jig

Then I dumped the skin to this jig for the last few dimples on the trailing edge using a hand squeezer.

Test fitting fuel line

And I also test fitted fuel pickup and overflow lines. The length of inlet felt a little too short. It’s supposed to be riveted on the rib using a small aluminum ring wrapped around the pipe, but the pre-drilled rivet hole is exactly at the bend where the mesh solders to the pipe. I am worried if I force the rivet the enforcement structure will squash the solder and eventually wear it out. I might drill another hole further out. We will see.

inlet mesh bending too close to the rivet hole in my opinion

Test fitting fuel overflow line, seem to fit ok

Test fitting the ribs

Then I proceeded to test fit the skeleton together. The ribs do not have much rigidity yet, so putting them together was a breeze.

Ribs test fit

Note I had the black clecos on the inside. I was hoping this will provide enough clearance to test fit the entire structure onto the wing. It turns out the answer is no, the cleco butts still interfered with the wing spar. So later I had to remove these clecos.

Test fitting the skin

I installed one side of the skin on table, then dumped the whole thing into the tank jig I just built. Using the jig I was able to cleco the other side of the skin with a little bit of force.

Once I got a few clecos in, the rest was easy.

Skin is clecoed

Test fitting the entire fuel tank

At last I clecoed the entire fuel tank to the wing. As mentioned earlier, some cleco’s butt was interfering with the clearance, so I had to back trace and remove skin, remove clecos, then re-cleco skin in order to put the fuel tank on the wing.

Fuel tank on the wing

With the tank on the wing, it’s starting to look like a real wing!

Match drill

I then match drilled every fuel tank hole visible on the skin. With each drill, I took a marker and draw a checkmark next to it so I remember which holes are drilled.

Up to now the build process did not really require match drilling, so I am honestly a little nervously with having to drill so many holes.

Once the drilling is done, I put the tank back to the jig. Tomorrow I will desemble it for thorugh clean, and will go into the sealant step.

Next step

I still have a few preparation work to do before breaking out the sealant.

• Countsink the fuel caps
• Put on enforcement plates, match drill those
• Drill new hole for inlet mesh plate (both ribs)
• Bend fuel senders
• Clean everything

Proseal steps

For 2 tanks:

• Rib 2 rivnuts
• Ffilling manufacturing holes
• Overflow tubes