Tonight I finished the roll bar install by riveting the last few rivets between the roll bar brace and the bulkhead, and the few remaining side skin rivets. For the rollbar to bulkhead rivets, I rolled the fuselage upside down and worked inside the cockpit. It’s so great being able to rotate it around freely, it makes working in the cockpit so much easier.
Tonight I installed the roll bar on the fuselage. The bar fit surprisingly well, it just slipped on like a perfectly-fitting shoe. I did have some alignment challenges on the right side, but after some fiddling around and using alignment tools, I was able to get it all to work. I riveted everything except a few rivets where the brace joins the bulkhead. I’ll get those with the rivet gun tomorrow when it’s not so late at night.
All was well until the very last river. It was getting late and I was hurrying to get to bed, and made a bad call. I was setting the last cherrymax rivet that held my fix in place, and the rivet was slightly misaligned. For some reason I thought it would straighten out, and I set the rivet on an angle. Instead of being flush with the top of the rollbar, the manufactured head was at an angle, with one edge protruding up. If it wasn’t a cherrymax, I would certainly drill it out and replace, but that’s so hard to do with a cherrymax. I decided to leave as-is and will use some filler to smooth out the surface. Super frustrating mistake after everything had gone so well.
Tonight I riveted together the two halves of the roll bar. It took some time to get everything to line up just right, but I was carefully aligning and riveting in random order around the heaviest curves.
Tonight I worked on my fix for the mistakenly countersunk roll bar flange. I finished the doubler, primed it, and glued it into position with clecos holding it in place. I needed to glue it so I could uncleco it without the doubler falling inside the rollbar.
I also made a test piece with exactly the same dimensions as the roll bar sandwich. I drilled two holes and tested the two different lengths of cherrymax rivets, because the thickness is almost exactly 1/4 inch, right between the two sizes. Based on this experiment, I chose the shorter length which gives a better looking shop head.
Tonight I continued riveting the roll bar, and have both straps riveted to the forward roll bar assembly.
After talking to Kevin at Vans, I decided I can save the mistake I made in the roll bar by creating a sandwich of aluminum around the mistskenly countersunk part. I made up a doubler, and ordered some longer cherrymax rivets.
I also started riveting the roll bar straps into place.
Tonight I finished final drilling the roll-bar, and then countersunk all of the holes. Unfortunately I made a silly mistake and countersunk 6 holes that didn’t need it. I think I’ll need to rebuild the roll-bar, but emailed Vans just in case there’s some kind of safe solution. It was really annoying to realize my mistake and the implications of having to order a whole new roll-bar and redo all this work. Unfortunately I think I’ll need to replace everything, since it’s all match-drilled.
Tonight I clecoed the forward and aft roll bar assemblies together using the two straps. The straps are lengths of flat aluminum, which require some bending to help them align with the curves of the roll bar. I wasn’t able to get them to bend very well, but I managed to get enough bend to make assembly easy.
I started the final drilling process, but need to take it all apart, debur, then reassemble and continue. I’m doing it that way to prevent too much build up of shavings that might cause a misalignment issue.
Tonight I clecoed then riveted the sections of the roll bar to make the forward and aft halves of the roll bar. This is done by clecoing each section to the fuselage and then riveting a plate in place to join the two sides of each half. Alignment was a little tricky, I had to carefully remove some extra material from the flanges of the forward half, so that they could join correctly.
Tonight I dimpled the roll bar brace and brackets, then riveted the roll bar brace brackets to the roll bar brace.
