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Empennage

HS rear spar riveted

Had a big night last night. It was time to start riveting the HS together. The plans say to start with the rear spar so who am I to argue.

I clecoed the rear spar channels and spar reinforcers together and put tape over the holes where the ribs will eventually go so that I don’t accidentally rivet those. I also put clecoes in the holes where the hinge assemblies will go so I didn’t rivet those holes either.

I then checked the plans to see what sized rivets I needed where and grabbed those from my hardware storage box. I grabbed the first one and went to push it into a hole. Uh ho…


The damn thing wouldn’t go in. I tried a few holes and encountered the same problem with all of them. A closer looked confirmed that I could slide the rivets into the spar reinforcers but for some reason they just didnt want to get through the spar channel holes. Then it hit me. 2 primer coats = smaller holes. By now the primer was rock hard. The only solution I could think of was to carefully remove the excess primer with a drill. It took ages to do it but I was very careful not to remove any metal. With that done, the rivets slid in with only a slight amount of force. There was still some friction there but I could push them in with my thumb without too much difficulty. The tails looked a little short on my gauge but the plans explicitly state that the ones called for are the correct size. I’m guessing Vans has had lots of people ask about it and have added this comment to the instructions. So I dusted off the pneumatic squeezer, adjusted it on the first rivet, then went to work.

I love the pneumatic squeezer. It gives consistent results. I then clecoed on the hinge assemblies starting with the inner 2-rivet per part ones. Then I did the outer 4-rivet per part ones. I found the rivet tails on the outer hinges to be a little long, but once again I trusted the plans and squeezed them.

The plans then call for the central hinge assembly to be bolted on. I rummaged through my hardware store and found the bag of stuff I needed. As I was looking for the correct sized washers I noticed there were thick ones and thin ones. So I got my hardware list and sorted out what was in the bag and compared that with the list. The correct washers I needed were the thick ones.

I bolted on the central hinge and wound on the nuts with my socket set until they just started to touch the spar. I didn’t want to over tighten these. I then got out my in-lb torque wrench and set to 22 inch-pounds (the plans call for 20-25) and carefully tightened the nuts.

I had no idea how tight 22 in-lbs was so I took it very slowly. It worked out that 22 in-lbs isn’t overly tight at all. I reckon it would be very easy to over tighten these if not careful. I then put some torque seal on the nuts so I can visually confirm they are still tightened whenever I look at them during my future pre-flight inspections.

I was pretty excited at this point (doesn’t take much does it?) and clecoed the HS skeleton together.

All looked fine until I clecoed the two halves together with the forward spar reinforcing angles. Hmm… that doesn’t look right.

I’m not sure if I have another “2 primer coats” problem or what. It was getting late so I removed the angles and separated the two halves again. I’ll need to do some more research/navel gazing to figure out how I’m going to fix that one.

Build time 3 hours.

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About gstrack

Husband and father of 2. Control & Instrumentation Engineer. Flying nut. Gadget geek.

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