Rivet count: Stuck at 779 rivets for the moment…
Shop Temp: 97F
A rare mid-week shop day for me! I quit my day job on Friday and won’t start my interim job until next Monday. The family was in the city visiting the Statue of Liberty, so I was able to get out to the shop for the whole afternoon!
It was all grunt work today. I had bunches of nose ribs and intra spar ribs to smooth out. It took a while, but between a needle file, the polish wheel, and some ScotchBrite, the edges are pretty smooth.
After getting that done, I had to modify a couple of the nose ribs and intra spar ribs to angle out from the front spar. This forms the edge near where the empennage attaches to the tail cone of the fuselage. Mostly some quick work with the hand seamer to get that done.
I also had to fabricate some cradles to hold the skin and skeleton during assembly. The instructions stress that a rough job is fine. This is not a jig, the frame is self-jigging. It is just something that holds the skins in place while doing the riveting. I traced the outline of a nose rib and intra spar rib as shown in the instructions and then jigsawed the four pieces. I added a wooden bracket at the bottom that I will screw into the table top during assembly.
Next up, some actual assembly work! You cleco the modified nose ribs and intra spar ribs to the center of the front spar and do some match drilling. Hardly worth firing up the compressor to run the drill. Lots of cautions to mark several holes to avoid dimpling them. Also, the top and the bottom are treated differently (the pattern of nine rivets in a square shows that the spar is properly oriented).
Then the real grunt work begins. I started prepping the skins for dimpling. The skins are symmetrical, no left no right, no top no bottom. Until, that is, you start marking the skins. So I spent some quality time with my soldering iron removing blue plastic.
With that done, I started filing the burrs and tool marks off the skins. There is a cutting tab every 4 inches or so around the outside of the skin. I filed those off first. Then I used some sand paper to remove those tool marks, and then finally finished with a ScotchBrite pad. The change is remarkable. From something that would snag and cut your skin to something with a mirror polish.
I still have a little work to do on them. They also need to be dimpled, but I ran out of time today, so they’ll wait for later.
I did sneak a peek at the next step in the instructions. I did a test fit of the string web assembly. This strengthens the tail right near the tail cone.
Next up, lots of dimpling and lots of countersinking… both spars and the web stringers need to be countersunk for the skin attachment rivets.
After that, it will go together quickly 🙂