March 28 & 29, 2020
So, it turns out that two stabilizers are only about half of the work in the total empennage. We’ve still got the rudder and elevators to assemble, so we got back to work. The first step is cutting out the stiffeners for the rudder. This took longer than expected, but was relatively easy once you figure out what each notch on the pre-formed piece is for. They come as two stiffeners end to end in one piece of metal. So, you first cut it in half, then mark it for each specific length, then trim with the shears, then deburr and shape each one. Took forever, but it had to be done.
With (all but one) of the stiffeners prepared, it was time to get the rudder skins ready for assembly. These things are crazy thin. It feels like they’re going to buckle and crease every time we pick them up. We match drilled the stiffeners to the skin, deburred the holes and took some scotch-brite to the edges to get everything ready for priming.
While match drilling one of the stiffeners to the skin Paul somehow missed the hole without realizing it and left a pretty good attempt at a new hole in the stiffener.
We may have been able to salvage it, but instead we just ordered another stiffener from Van’s and moved on to other things while waiting a few days for the replacement to arrive. Overall it was a minor ~$15 mistake, I’m sure we’ll make many more and more expensive ones in the future.
Since the stiffeners need to be riveted to skin before working on the skeleton we elected to prime the stiffeners and skin (only where the stiffeners are) with SEM spot primer.
After the primer dried we setup the back-rivet plate in the workbench and got to work installing the stiffeners. Paul really likes back riveting. I find that somehow I always manage to put an angle on the rivets, but he can’t seem to mess it up – so he gets to do all the back riveting. After getting (almost) all the stiffeners in place, we set the rudder skins aside, waiting for some more parts to build up for another full scale priming day.
Primed, ready to rivet 
Stiffeners riveted on
Next up, we cleco’d the rudder skeleton together and match drilled all the skin to the skeleton. That kind of work is starting to feel deceptively easy now and goes by pretty quickly. We’ve developed a system of marking the holes to make sure we don’t miss any.
At the top of the rudder is the counter-balance assembly. This consists of a lead weight bolted into the rectangular rib. The lead weight gets countersunk while the rib gets dimpled to allow the bolt to sit flush.
This is when Paul realized that we didn’t have the correct size dimple die. We had one for a #8 screw, but not for the #10 screw. You could probably get away with dimpling with the #8 and then just using the screw itself to finish the dimple as you tightened it down into the lead weight, but we just stopped and ordered the correct dimple die. It’ll be a few day delay, but we can move on to other things while we wait.
Cheers,
-Kacy
(Total Build Hours: 87.0 hrs)