Ready to assemble the vertical stabilizer (almost)

Rivet count: 10

Garage Temp: 18F – 37F

My father-in-law keeps asking how many rivets left to go… Since the last parts of the kit aren’t ready yet, I don’t have the actual count of what’s left to go.  The online estimates I’ve found so far are 14,000 to 16,000 rivets.  So I’ve got a ways to go!

When last we met, the vertical stabilizer was assembled with clecos and match drilled.  It kinda looked like it belonged on an airplane.

2014-02-17 12.37.12

Then I had to take it all apart!  I got as far as taking the skin off last week (and deburred it as well).

Today, I started working on all those parts that hold it together, the ribs and two main spars.  As I took each piece off the main skeleton, I first did a quick deburr of the holes so I wouldn’t forget.  Then I did a rough smoothing of the edges.  The “standard” test is to run your finger along the edge.  If it draws blood, it is too rough!  I tried to avoid the blood sacrifice, but there were clearly parts along the edge that could cut me if I wasn’t careful (we don’t have any time for a trip to the emergency room!).  As with the vstab skin, I used the bastard file to take out the worst snags (typically tags that held the part in place during CNC cutting that were roughly cut out).  Then a couple swipes with a fine file so that my scotchbrite wheel didn’t have to work too hard, then a trip to the bench grinder with the polishing wheel.  Whatever was left I got with a set of needle files and some scotchbrite pads.

The edges polished up quite nicely!  The rear spar doubler started with a particularly rough cut.  It looked like perhaps it was cut with a water jet.  It took a bit of filing to get pits and tool marks out, but it ended up with a fine shiny surface.

Then it was time for priming.  I’m using green Dupli-Color self etching primer.  I’ve seen lots of different colors used.  Jack Dueck likes grey.  One guy is using a bright white.  I’m using green because that’s the color the auto shop next to the pizza place stocks. It’s pretty nasty, so I made sure to have the big garage door open.  The paint lightly etches the surface coat of pure aluminum and gives better corrosion protection (and the parts are easier to handle with less scratching).  I used Jack Dueck’s technique.  I lightly roughed the surface with a scotchbrite pad and then cleaned with acetone (my rags go into a sealed paint can to prevent spontaneous combustion).  Then you hit the wet primer with a heat gun to get it to flash over. The idea is that you can then work with the pieces in minutes rather than waiting an hour for a hard coat to form. You only need a light coat of primer, so it looks a little like I did the parts up with camo paint.

2014-03-01 14.02.56

With the parts primed, it was finally time to go back and re-rivet the part I messed up.  The front spar and doubler went together very easily this time.  I ended up back riveting the flush rivets on my tungsten bucking bar.  I saw this technique on another builders site.  The hardest part was getting the compressor warm enough to start (it was down to single digits overnight).  I squeezed the four universal rivets in the top row.  The plans called for 3-3.5 rivets.  I could not for the life of me find any in the kit, so I shortened four 3-4 rivets on my belt sander.  Worked great.  One shop head is a little overdriven and one is a little under driven, but they’re in spec, so I won’t mess with them.

2014-03-01 17.12.44

The next step is dimpling to get ready for all those flush rivets!  The skin was the hardest part.  I got to fire up my DRDT-2 dimpler table.  It does a nice job, but the interior of this pre-folded skin is really hard to work on.

2014-03-01 17.08.18

The other dimples weren’t hard at all.  I used my hand squeezer to knock them out.  I found it a lot easier to clamp the pieces to the table before running the squeezer.  I was hoping to do more, but I had a question about the countersinks needed to hold the doubler to the rear spar.  I’ll send an email off to Van’s to see how to proceed.

2014-03-01 17.07.12

(update: I found this note in the “Plan Gotcha’s” page on Vans Air Force: “page 10-05 figure 1 shows two locator holes. Having built the VS previously I had to drill out a rivet in the VS in the bottom location shown on page 10-05. No biggy but if you think of it omit this rivet while building the VS. Even though page 06-04 figure 2 shows to skip that hole, it’s easy to miss.”)


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