April 16 & 17, 2020
Today was spent riveting all the skeleton parts for the rudder. Most of these rivets were easy to get to with the squeezer, but some took some creativity. There’s 4 rivets that go between the R-710 horn brace and R-405 rudder horn that are optional pop rivets. With a longeron yoke and some washers as spacers under a squeezer set, we were able to go through the hole in R-710 and squeeze all 4 of those rivets.
Rudder Spar & Lower Rib 
Rudder Horn & Brace
The other optional pop rivets are between the R-710 horn brace and the R-904 bottom rib. These were fairly easy to get to with a squeezer. The 8 rivets inside the R-710 brace that go to the skin were a bit trickier to get to, but again, with some washers as spacers under the squeezer set and a deep yoke we were able to squeeze all these rivets without too much issue.
The rear most rivets on the skin on both top and bottom required a custom bucking bar to be made.
There’s Just No Room
We took some left over 1/8″x1.5″ steel bar from the trim tab bending setup and ground it down until it was almost non-existent. I had to hold the bucking bar with pliers and brace it off the table with a flat-head screwdriver while Kacy shot the rivet with a gun, but all of the rivets set-up and we got to avoid using pop-rivets. The only pop rivets we used were the 2 that were absolutely required between the 902 spar and 903 tip rib.
Grinding the bar 
Skiiiiiny bucking bar
The trailing edge wedge still needed countersinking. It’s a very delicate balance between being deep enough so the skins sit flush and shallow enough that you don’t knife-edge the holes. I had a few holes that got opened up a bit, but Van’s confirmed that because these were being sandwiched on both sides with dimpled skins that as long as the rivet was set properly, an enlarged hole in the wedge wouldn’t be a strength issue.
It took a few tries of countersinking and fitting the wedge into the skins to make sure we had a trailing edge that sat nice and level on both sides. After the skin was looking nice, we took the wedge out, covered it with 3M 5200 sealant and reinstalled it. I had previously drilled out 2 pieces of 48″ long 1.5″ angle aluminum as trailing edge guides. This is described in the instructions and should make for a nice straight trailing edge. We cleco’d the angle aluminum in place and set the rudder aside for a few days to fully cure into position before riveting.
-Paul,
(Total Build Time: 136.0 hrs)