Much like the VS, my Dad helped install the rudder fairings. The rudder came out looking great, with the light installed and some wiring and a molex connector installed too.
Rudder fairings
Vertical Stab Fairing
With my Dad in town, it was great to get his expert advice and handiwork with the firbreglass fairings. Being a boat builder back in New Zealand, my Dad has a lifetime of skill and experience working with all kinds of things including fiberglass. He’s a master at the stuff, so he went to work on the rudder and vertical stabilizer fairings.
The VS fairing needs an insert of glass on the aft edge and Dad made quick work of getting it made up and glassed in. the only real challenge was getting the fairing square. The piece is molded in two half’s then glued together, but there seems to be some slight misalignment of the halves casing it to be slightly lopsided. Dad got it pretty straight, so it looks awesome.
Finishing Aft Fuse
Today I officially finished section 10, the aft fuselage. With the empennage attachment finished, I completed the final step in section 10, riveting the forward bulkhead to the top skin rib.
I positioned the aft fuse on my work benches, and rolled it onto it’s side. By lying down inside the fuse, I was able to rivet 2/3 of the rivets using my new “main squeeze” hand rivet squeezer. The last rivet needed to be bucked as it was too tight against the skin, and the rib. Using a double off-set in my rivet gun I bucked it. Not my best rivet, but good enough.
Then I completed the aft fuse by screwing on the inspection port covers on the aft end. After I located the correct set of 16 screws, I had a frustrating time with a couple of the nutplates, where the screw wouldn’t sit squarely in the hole and wouldn’t engage with the nutplate. Withou the covers in place I was able to get the screws in, and that seemed to fix the issue. Covers are now installed.
Hanging the Rudder
Today was a big day, as I was able to attached the Vertical Stabilizer and hang the rudder on the aft fuse. I then added the elevators and finished up section 11. Well, it’s not really done, as there is some electrical routing that still needs to be done, but that can wait for now.
First I installed the VS attach bracket, then the Vertical Stabilzer itself. I used temporary fasteners, as this is all coming apart again soon.
With the VS on, I attempted to hang the rudder. Everything looked good except the gap on the top hinge was too narrow for the rod end bearing to fit. I took the rudder off and attempted to bend out the Ganges on the hing using a small wooden block. Measuring with my calipers, I found it to be about a millimeter narrower than the middle hinge. After several attempts, and with Jen’s help, I was able to get it to fit.
With the rudder on, I installed the elevators. This required supporting the tips of the HS so that the elevator counterweights didn’t cause the fuse to roll over as I installed these one at a time.
With the elevators on, I measured the clearance between the rudder and corner of elevator and trim tab. It was 3mm more gap than the minimum, so I left it as-is.
Drilling Horizontal Stabilizer mount holes
I had been stuck for a few days, as I didn’t have the right drill bits to finish enlarging the holes on the rear spar. I did have a 1/4 inch drill, but I really wanted a reamer. I reached out to my friend Murlin who offered to lend me some bits while mine were in-route from Aircraft Spruce.
Using a #C drill bit, and a 1/4 inch reamer, I drilled a perfect hole in the top right side of the spar. The bottom two holes were positioned such that I needed a longer drill bit to clear the aft fuse. Rummaging through my box of used tools, I found a 12 inch long 1/4 inch drill bit, and a 12 inch long 3/16ths bit. This was quite lucky! I practiced with them on some scrap to ensure they worked ok, then drilled two more great holes through the spar. Not as clean as the reamer, but close enough.
With the holes drilled, I bolted on the Horizontal Stabilizer.
Mounting Horizontal Stabilizer
Today I rearranged the benches in the shop, then installed the HS on the aft fuse. It’s neat to have this attached and to see how it all fits beautifully together.
Drilling elevator horns
Yesterday I reoriented the HS and attached the elevators so it’s sitting vertically on the bench. This makes it easier to drill these important bottom holes on the elevator horns. I marked and center punched the location for the first hole, then drilled it. The right hand elevator horn is slightly aft of the left, as expected, per the plans.
Tonight I clamped up the trailing edges, and then spent time shaping up a drill block.
Once I had a perfect fit on the drill block, I clamped the elevator horns and drilled the hole in the left elevator horn. These came out quite well I think.
Drilling elevator horns
I found that my trim tab is indeed twisted, which was causing most of the misalignment. I discovered this after removing the tab and setting it on a flat surface.
With the trim tab set aside for now, I clamped up the trailing edges of the elevators, and found I still had a difference of 3/16ths between the counterweight arm and the HS, when holding one elevator counterweight arm flush with the HS. from the research I’ve done, I’m going to leave this as-is, and move on. Provided the trailing edges are flush, it shouldn’t be a problem.
A twist in the tail
Today was frustrating. My next step is to drill the elevator horns to allow them to be bolted together and attached to the elevator push-rod. The critical part of this step is making sure both elevators are aligned with one another. The plans suggest taping the elevator counterweight arms to the HS, and then going about drilling the holes. Sometimes the counterweight arms are not completely square with the trailing edge, and doing it this way can result in the elevators being out of alignment on the trailing edge. The common practice among builders is to clamp the trailing edges together and use that as the guide instead. I had picked up two 8 foot lengths of aluminum channel to serve that purpose, and with the arms taped to the HS, I laid one across the trailing edges. Unfortunately, there was a significant difference between the trailing edges, almost an inch!
After some investigation, I believe there are two problems. 1. While the trim tab’s trailing edge is very straight, I think the trim tab is twisted. 2. One of the elevators has a slight twist causing the counterweight arm to be out of alignment.
My next step is to remove the trim tab and check it for twist. With it removed, I will also check the elevators to see if I can identify the ant twist. My hope is that with the trim tab removed, the problem will be mostly resolved.
Drilling elevator horns
Today I drilled the 1/4 inch holes connecting the elevator horns to the bearing on the horizontal stabilizer. This worked out well, and I’m happy with the result. The next holes I need to drill on the horn are perhaps more critical, as they set the alignment between the two elevators.
First I needed to resize the bushing supplied by vans. I put it in the drill press and sanded it down until it fit snugly in the bearing. I also drilled out the center to #30, as the inside diameter wasn’t quite large enough.
With the bushing in place I drilled the left elevator hole
Then I removed the elevator and step drilled it up to 1/4 inch, and deburred the holes.
Then it was onto the right elevator, again this went quickly and easily.
Finally, I selected the appropriate number of washers and bolt length (-13), to secure the elevators.
