I couldn't help but put some of the front deck in place to see what it looked like. A few cushions to sit on and 10 minutes of airplane noises later, I got back to work.
I couldn't figure out how to reliably locate the two stub ribs that set just inside the two big outside ribs, so I inverted everything on the bench and clecoed the existing holes to the skin. That let me set the stub ribs on the skin and clamp to the flanges of the center subpanel.
I didn't get pictures of the interim steps - I fluted the flanges of the outboard subpanels (it took a lot and the holes still weren't lined up very well) and clecoed those in place. The top flange of the firewall isn't pre-drilled at all, so it has to be matched up to the skin and drilled. I did the center portion and then attempted to get the skin sucked down to the longerons. No luck. I used a ratchet strap, which helped a little, but I still couldn't get the longeron holes to match up with the skin. The photo is deceptive because it looks like most of the skin is clecoed down, but the majority of clecos are at a severe angle - definitely not good enough to finish drilling the firewall. Skins always seem to be a fight until you figure out the perfect order of attaching everything. I'm going to have to take it all apart and try another approach. I might try starting at the longeron on one side and then working my way over to the other side.
