Slow progress

I’m making slow progress on getting the lower wing skins riveted on; I’ve chosen to do that work with a partner, even though it slows me down. So while I’ve had no riveting help, I decided to get started on the fuselage – specifically, on the firewall.

It’s a relatively easy place to start, all that’s necessary is a bit of plans study and some time to identify all the stiffeners, brackets and gussets that are required. The fit on some of these parts leaves a little to be desired, however.

Here’s one example where diagonal stiffeners nest into gusset at the upper firewall corners, all of which rest under steel brackets. Unfortunately, that little cutout in the gusset isn’t deep enough to allow that stiffener to fit correctly with prepunched holes in the firewall – so some adjustment is required. Vans’ plans say to tweak the end of the stiffener to fit but that would be too easy, wouldn’t it? To preserve edge distance on that part, I pulled out my trust Dremel tool and routed out the cutouts in the gusset. Problem solved, and I’ve kept an extra 0.0001 percent margin in the structure. I feel much better.

Fitting firewall parts

There are also a couple of 0.025″ shims that ride on top of those stiffeners. They took a few extra minutes to fabricate, no big deal. There’s also an extra stiffener that must be fabricated from 6061 angle. The stiffener itself is easy…finding the stock you’re supposed to cut it from is the challenge. There are three pieces of angle stock that could be used, just don’t choose the one that’s already cut to length for another part!

After getting the minutia squared away, I clecoed the firewall together – a nice bit of visual progress!

Firewall clecoed together