May 17th and 18th, 19th 25h
In order to move ahead with riveting the leading edge and main skins. we needed to fix a couple things.
- One of the countersink did not go well in the main spar. I took a very conservative path fixing this. I filled the hole, re-drilled and re-did the counter sink. In addition, I added a doubled to reinforce the 10 holes around the fixed countersink. As well, I added an angle to attache the rib to spar via 4 holes instead of 2, which reduces the load in the hole with the fixed countersink.
- The most inboard rib in the leading edge ended up having holes too close to the edge. I took the conservative oath here as well. I ordered new ribs and I re-did the work. The new ribs look great.
Then I moved on to last items in the leading edge and the main spar, before riveting everything together, the point of no return:
- I finished installing the stall horn with the new hardware and riveting it to the leading edge.
- I torqued the tie down assembly to spec
Afterwards, I finished fitting all the main skins, the leading edge and the fuel tank. Everything fit together great.
Then, after checking that everything looked great, we went on with the riveting of the leading edge and main skin.
First, we riveted the new inboard ribs to the leading edges. This went great.
Then we moved to rivet the leading edge ribs to main spar. There is two issues here. One is that it is very hard to reach the rivets in the middle ribs with the bucking bar, Van recommends using LP4 pulled rivets here. The other is that the ribs from the main spar get in the way of the rivet gun. We started by riveting the ribs that we can access with an offset rivet set, but there was still a small angle that leads to the head of the rivet gun hitting the main spar. So, it looks like going with LP4 rivets for all the ribs from leading edge to main spar is the way to go here. But we are holding on doing these until we confirm with Vans.
Then we moved on to riveting the leading edge skin to the main spar. This went on very smoothly, especially given that we can use the pneumatic squeezer here. The results looked great.
Afterward, we went to riveting the skin to the main spar and skeleton. We started with W702, moving from the center to outwards as recommended. This went very smoothly and the results looked great.