Aligning and clamping the skin to the frame
Starting to match drill and install the clecos (temporary clamps)
Next up, I cleaned and deburred all vertical stab frame parts then reassembled with clecos and installed the rivets. A few of the rivets were hard to get at with the gun or the hand puller. I ended up having to drill out 5 rivets due to them not being quite flush. I got four out of the five riveted to my satisfaction but the 5th one caused a slight oversized hole when drilling out so I’ll have to install an oversized rivet there. The oversized rivets are on order.
I moved ahead with initial alignment and drilling of the vertical stabilizer skin. Everything lined up fairly well so, after convincing myself that all was good I commenced match drilling the skin to the frame. I got through one side. Next I’ll flip it over and press the skin into place with some weights then match drill the other side.
First side is match drilled!
Flipped over and ready to align the other side
Today I match drilled the leading edge rib and the tip rib to the frame, then updrilled all holes in the frame with a #30 bit to prepare them for rivets. Now I need to disassemble the frame, deburr and clean all parts, reassemble and rivet.
All holes in the frame have been updrilled
Assembled on the footprint and clamped
Checking rib for right angle
Checking spar for right angle
Mating holes drilled and clecos in!
With the spar all bolted and riveted it was time to assemble and align the vertical stabilizer frame and match drill the holes. I did a lot of research and looked at every picture I could of others performing this step. It’s critical that the frame be square and flat. Per Sonex suggestions, I drew the footprint on my workbench and used that as the template for assembling the frame with clamps and getting everything aligned properly. I checked for 90 degree angles and made sure everything was perfectly flat. After checking and rechecking (about 20 times) I finally got the nerve to start drilling the mating holes. I found that a 6″ #40 drill bit made it easier to get a straight shot at the holes. Phew! Everything turned out great! Next I need to mate the nose rib to the forward spar clip and updrill everything to #30, then clean and deburr and rivet the frame.
Rivets in, now time for the bolts
Had to use an extra washer to compensate for the grip length
Finally had a chance to rivet the main spar tonight, T09-01. I installed some of the bolts as well, but the grip length on some of them was too long and I had to use an extra washer on those bolts as others have done. I placed an order tonight for more washers. I also went ahead and ordered a few AN3-10A bolts as it seems that most end up needing them for bolting the attach angle to the spar since the AN3-7A bolts end up a bit short.
Notice the chip in the bolt hole.
I had another long delay while waiting on a new T12-05 attach angle from Sonex. When drilling to the final size for the bolts, one of the holes got oversized when the drill broke through the piece. An email to Sonex confirmed my fear that the angle would have to be replaced. $39 + shipping later and I am now finally ready to finish the aft spar. Spent some time yesterday updrilling the new angle piece. I then disassembled everything, cleaned it all up with scotchbrite and mineral spirits and reassembled. Next step is to rivet.
Spar pieces all cleaned up and ready for reassembly.
Nice and square
Its been awhile since I have had a chance to get back out in the shop. It felt good to get back to the build. First, I had to remake clip SNX12-06 because of the mess up when match drilling to the spar. This time I was careful to clamp it good and tight while match drilling and it all went well. I then spent a few minutes test fitting all the vertical stabilizer pieces to make sure there is no twist. All looks good! I can now move on to deburring all the spar pieces, reassembling and riveting. Then it will be time to assemble the vertical stabilizer frame.
Test fit of the vertical stabilizer frame
Aft spar updrilling complete
Notice the clip is not quite aligned with the blue line
The square confirms my fear
Test fit of the vertical tail structure confirms that the misalignment is causing a twist in the bottom rib. On the bright side, this is the first time I was able to assemble the pieces and see the vertical tail start to take shape!
I had to wait to move forward with updrilling of the aft spar until I ordered and received some special long-reach clecos for the thicker parts of the aft spar assembly. Once I had those in hand I was ready to start the updrill process.
Everything went smoothly UNTIL…the updrilling was complete and I realized the clip that will be used to attach the bottom rib of the vertical stabilizer ended up slightly skeewampis. Dang it!
I did a test fit of all the vertical stabilizer pieces to confirm this was going to cause an issue and sure enough this clip will have to be remade because it caused a slight twist in the bottom rib.
Re-making this clip will be my next step in the vertical tail build. I’m not happy about it but I want to ensure the tail is completely flat and true. On the bright side, I should have enough of the flat sheet to make another clip without needing to order more. At least this wasn’t an expensive error!