Today was another great day in the shop. Lots of rivets, lots of ER tank planning and work. As you’ll see, I committed to doing the tanks, so there’s no turning back now. (Yes there is.)

Let’s dig into the pictures. I started by clecoing together the rear spar channel, reinforcement bars, and plates.

Then, the riveting started.

Slowly, I made my way inboard (left to right in this picture).

A few minutes later…

After removing the clecos…

Then I moved to the riveting I could do at this mid-span reinforcement plate. There’s only 5 rivets you can set right now.

And without the clecos….it looks like I didn’t do anything.

Same story on the outboard end.

I found a good spot for the rear spars.

Apparently I got distracted with the second spar and didn’t take any pictures. Oh well. It’s also sitting on the wing stand supports just like its brother.

I decided at this point I needed to make a final decision about ordering an extra set of tank stuff to duplicate the inboard tanks into the outboard position. Before committing, I decided to cleco together the left tank skin, baffle, and z-brackets, then set it on the spar (with all the wing skins clecoed into position to keep the main spar straight.

Then, I decided to see how aligned I could get the tank skin and wing skins. Here’s the lower side of the left wing.

And the upper surface of the left wing.

I stood back to take an overview picture. Maybe it’s just nerves, but I hesitated about starting to make holes in metal here.

I guess if I’m going to do this I need to take the next step. In this case, it would be to make the inboard z-bracket. From a few days ago (https://rv8build.com/2026/07/03/tiedowns-er-tank-planning-devinyling-wing-skins/), I had some 6061 – T6 Z channel that is 1 1/8 by 1 1/8 instead of 1 1/8 x 5/8.

Here’s an action shot of me matchdrilling the new from the old.

And here is the new z-bracket clecoed to a left tank skin.

Next, I set the tank back in it’s perfectly-aligned position, and verified that the new z-bracket prevents any interference with the tiedown bracket.

After removing the tiedown bracket, the aligned larger z-bracket looks like it’s going to work perfectly.

So, I clecoed on the rest of the z-brackets, and put some double-sided tape on the spar side of all of them.

Next, I set the tank skin, baffle, and z-brackets (with double-sided tape) onto the left main spar, then removed the 14 clecos shown here.

After removing the clecos and lifting the skin and baffle off… I’m left with z-brackets, taped to the outboard half of the spar in final position.

Whoa, the inboard z-bracket is exactly touching the tiedown bracket. I think I’m going to trim that back a little. (The tiedown, not the z-bracket).

This picture is of the RIGHT main spar after drilling the left spar, hanging the right skins, then repeating the alignment exercise on the right ER tank.

I stopped here on the spars, because any more drilling really requires the skins to be fully clecoed to the spars and ribs, which aren’t prepped yet.

But, by 3/8-19 tap arrived!

So I got both tiedown brackets tapped. Wuhoo!

Huge day today. 112 rivets. 4.0 total. 1 hours on the spars, 3.0 hours on the extended range tanks.