A few odds and ends were on the menu for today. While I'd match drilled almost everything to the center section side skins, I still needed to drill the baggage corner ribs to the side skin. These are the ribs that essentially connect the bottom skin to the side skin in the baggage area (not even sure if they're considered ribs since they lay flat on the bottom skin). The ribs are already match drilled to the bottom skin, but the outside flanges of the ribs need to be drilled to the side skins.
I crawled under the fuselage and clecoed the pieces in place. It was then I realized that I still needed to dimple the ribs. Since the bottom skin was already dimpled, without the ribs dimpled they wouldn't set flat to the skin, meaning the drilling to the side skin would be slightly off. I pulled the ribs out, dimpled them, and put them back in place. Duh moment number two - everything is dimpled now except the curved portion of the side skin! That means there is a flat piece of sheet in between the bottom skin dimples and the rib dimples. Again, that means the vertical alignment to match drill the flange to the side skin would be slightly off. I didn't want to pull the side skin off yet to deburr and dimple the curved portion, so I'm just going to wait until later to finish up this match drilled portion. This picture is a little hard to orient to - it's looking up at the rib from underneath the fuselage (the side skin is the light grey portion with the big step hole in it).
I moved on to the next single line of instructions that took 2 hours (this is the rule now - no more hand holding). The front fuselage bottom skin gets holes cut into the outside portions to accommodate the gear leg towers. I made a copy of the full size template and aligned it with the skin edge and rivet holes and marked where the cutout needed to be made. Now for the time consuming part - trying to figure out how to make an oval cut in thick aluminum sheet. I tried a number of different methods, but in the end my right angle cutoff wheel worked the best. I slowly nibbled away at the hole with the cutoff wheel then used a file to finish it up.
I test fit the gear towers, and the fits are close, but the holes are going to need some tweaking when it comes time to mount things for good. The main tubes of the gear towers fit well, but the welds on the tubes hit the edges of the holes. By design the large hole is super close to one of the rivet holes, which I don't love. I'll have to do some research to see what people tend to do there. I also drilled the brake line hole.
This is how the gear tower fits up against the 904 bulkhead and exits out the bottom skin:
Now for the horrifying part - the tube hits the flange of the 904 bulkhead, meaning the bulkhead flange has to be carved out to fit the gear tower. This is one of those tasks where screwing up is not an option given that this bulkhead is pretty well baked into everything built so far!
Now back to the forward fuselage. The 713 auxiliary longerons attach on an angle as one of the side skin stiffeners. Because the skin transitions from flat at the center fuselage to slightly curved at the firewall, these longerons have to be twisted slightly to fit. I started with the left side and put it in the vice and twisted it just a few degrees.
I clamped the longeron in place, trimmed the aft end so the angle matched the bulkhead angle and match drilled it to the skin and the firewall bracket. Unlike most skin rivets which are 3's, this longeron gets bigger rivets (4's).
