Category Archives: vstab

More flying/working on the -12, shop getting close for the -14!

The shop is getting closer to being ready to build again.  Most importantly, I got my Dad’s old pencil sharpener mounted on the shop wall.  I really loved this one as a kid and I got my Dad to give it to me “pre-inheritance,” as it were.  My siblings are jealous 🙂  This is apparently now a vintage sharpener with a couple on sale on EBay.

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I’m still organizing the shop.  It was easier when I first set things up because I didn’t have all the parts and tools.  I haven’t gotten into the boxes yet, but at least now I have the cabinets and shelves set up.  The compressor is now online and the air hose reel is mounted.

The tail feathers are now all up and hanging securely.  The rudder and vstab are along this wall because the hangar had a small leak in the corner and I didn’t want rain dripping on my nice parts!

I would have gotten more work done, but (1) I went flying in the RV-12 and (2) my next door neighbor and the CFI-S I’m working with both stopped by and chatted for a couple of hours 🙂   The flying went really well.  I’m getting a better feel for the plane.  I still haven’t left the airport pattern, just working on landings.

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I did actually work on one part.  My son had deburred the new cockpit handle latch last week.  I finished it up (it was steel, so it needed some touch-up after the humid week we had) and primed it.  I’ll dig out some gray Rustoleum to match the cockpit color so I can install it next week.  I have to drill out three rivets and pop-rivet the bracket in place.  It took a bit to dig out the new page for the instructions to make sure I orient the part correctly (and to drill out the correct rivets!).

Next week, I’m out cycling with my brother, but I’ll be flying and building again in a couple of weeks.

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Hey! There’s a tail on there!

 

 

We spent Boxing Day and the following day over at my sister’s house, so I only got a little time after Mass to work on the plane. With the side skins riveted and the wiring and static lines routed, it was time to get started on the aft deck and prepare for the top skins.  Most of the miscellaneous small parts are now primed and ready.  In addition to these aft deck parts, I also primed the top skin and it’s stiffeners.

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The aft deck clecoed in pretty easily.  I’m still amazed at how well everything lines up.  At this stage, you just have to do some final drilling for the attach brackets.  A couple C-clamps made that pretty easy.

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Now there are a lot of rivets to hold the aft-deck together.  Not surprising considering the load the tail will put on it.  A couple of the rivet call outs are wrong where the length doesn’t take into account the F-01411E.  I was able to squeeze most of the rivets with my standard yoke and my 4″ flat-nose.  I had to shoot a couple of hard to reach ones though.  There is good access through the lightening holes for that.

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It looks very pretty!

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In the next step, I had to pull the vertical stabilizer down from the wall to temporarily mount it to drill a couple holes.  The plans warn, “It is critical to drill the holes perpendicular to the Vertical Stabilizer Spar.”  I used a wood block with a #12 hole I drilled using a drill press.  It kept things very square.  The plans say to use a cleco on top and bolts (with temporary nuts) to hold it below.  I found that a cleco through the bracket hole worked just fine.  Do note that you have to thread the wiring harness through the systems hole to complete the mount.  Some extra hands would have been nice, but I was able to do it myself with only a little awkwardness.

 

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Next step:  The three top skins get assembled and mounted.  I’ll need a hand to get the topmost one on since it will be a long reach.  Some builders lined the inside with blankets and did it that way.  We’ll see.

 

 

Vertical stabilizer done! (for now) and the many, many small parts in the rudder

Rivet count: 303

Garage Temp: 28-40F

I just got back from a business trip, my daugher is back from college for Spring break. and we’re having a contractor in to look at some house upgrades, so it was a busy weekend.  I had to make some deposits in the bank of family harmony rather than spend the weekend in the shop.  I did manage to get two half days in however (thanks Honey!)/

This weekend was all about assembling the vstab.  Everything was pretty much ready last week except some countersinking and dimpling on the rear spar doubler.  On Saturday, I dove right in.  First step, countersink the big spar doubler…

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I used one of my countersink cages.  It took a few tries to get the depth right.  I started with a test hole in a piece of angle left over from the EAA workshop.  Even with the cage, you still have to be careful.  You have to keep the cage perpendicular to the surface and take care not to push too hard or you end up with an oversized countersink.

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The picture is a little blurry, but it shows the countersinks on the forward side of the doubler.  The orange tape is to remind me not to countersink that hole (it is used later when the vstab is attached to the fuselage).  I countersunk a little deeper than normal because this is a sub-structure, so a dimple in the spar sits in the countersink rather than an rivet head.

With that done, I dimpled the spar and put the pieces back together:

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I was able to squeeze all of these with my hand squeezer.  The 1/8″ rivets are a bit of work to get going, but they came out rather nice.  You have to take care to watch the plans.  Most of the rivets are placed with their manufactured heads on the aft side of the spar, but the flush rivets on the bottom of the spar have their manufactured heads forward.  The aft ones are done that way so that there is less interference when the skin is riveted on a few steps later.

With that out of the way, it was time to put the framework back together.  The plans note (in bold) to be careful with the order.  At least one RV14 builder didn’t pay attention and then had to work a lot harder to get his assembled.  The idea is to assemble the forward spar and ribs first.  Then the skin is added on.  Then, the rear spar is added.  This can be done with just three pop rivets (for the center rib).  Everything else is reachable.  Here’s the forward spar and ribs… time to squeeze 8 whole rivets!

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Next, the skin goes back on.  I was worried that it might be a tight fit after dimpling everything.  I needn’t have worried.  It all went back together without any real fiddling.  I started at the nose with a cleco on each side, then worked my way back along the ribs one side at a time.  Take note of the Sanka coffee can.  I don’t drink coffee (and most doesn’t come in cans anymore either!).  My father-in-law gave me all of his old clecos and the can came along for the ride.  I think of him (and the BD-5 he never quite finished) whenever I reach for a cleco!

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With the preliminaries done, it was time to get down to business.  No more squeezing a couple rivets around a flange or two.  No, it was time to break out the tungsten bucking bar and the rivet gun!  The bar is very dense and very hard.  It makes a really nice surface to set the rivets against.  I wrapped the bar in some tape so that it wouldn’t mar the inside rib surface so much. 2014-03-08 13.00.13

I put a towel down inside the assembly in case I dropped the bar (as it was sure to leave a mark!).  You start at the center rib intersection and then work to the top, then back to the bottom, then to the aft surface.  It was a little unnerving.  I hadn’t driven any rivets since the class (the back riveting on the forward spar hardly counts!).  These were all going to be visible forever!  It was a bit hard to see whether they shop head was the right size, but they seemed OK when I got the gauge on them.  On Saturday, I finished all the interior rivets and most of the edge rivets (I squeezed most of those).  I messed up a rivet in the nose and decided to call it quits for the day (and to get back in time for the contractor who was visiting).

I picked up again Sunday afternoon.  First order of business was drilling out the bad rivet.  I read a hint about using drill bits meant for plastic.  These have really sharp 60 degree tips.  It makes it a lot easier to get started with out the drill wandering around.  I also used a punch to have a really sure starting point.  You can see how nicely it starts!  It is a 1/8″ bit so I just use it to get the hole going and then switch to a #40 bit to finish drilling through the head. 2014-03-09 12.31.36

Next, you put a pin punch into the hole and break off the rivet head.

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Then just punch the rest of the rivet through and you’re done!  The blue here is from the Sharpie mark I left on Saturday so I would remember to drill this one out.

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The rest of the riveting was time consuming, but mostly uneventful.   With the whole assembly riveted together, it felt very strong and it is is extremely light.  The rear spar went on pretty quickly.  Right after driving the first couple of rivets, I had a terrible thought!  Remember the towel I was using inside the skins to keep the skin from denting…   I remembered it then too!  I peeked through the lightening holes to see if I could spy it, terrified about leaving it rattling around inside there.  Then, I noticed that I had put the shop towel off to the side with some other tools.  Sigh!  Of course it wasn’t in there!  I had carefully shaken everything out because I didn’t want any chips or extra dust in there.  With that, the vertical stabilizer is done!  (Well, until I add the fiberglass tip and farings later on).

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To celebrate, I updated the background image to show the vstab in green (done) and the rudder in red (in progress!).

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There wasn’t a lot of time left in the day as I needed to head home and cook dinner (turkey legs, mashed potatoes and gravy, zucchini, and strawberries), but I wanted to at least get started.  The rudder parts are spread through a number of the part “sub-kits.”  The ribs were pretty easy to spot as were the rudder horn and the stiffeners.  The trailing edge is manufactured (by you!) from a longer edge (actually a longer part from an RV-10) so it has a label in the initial part diagram, but is not in the inventory.  No, the hard parts to find are the small doubler plates (R-606PP, R-608PP, R-609PP).  They are not listed in the inventory.  They are not in the “miscellaneous” clear plastic bag (where the VS-01401 was hiding).  Noooo… the three plates are hiding in a small brown bag labeled “small empennage parts.”   One is labeled, the other two have no label (but match the part layout).

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The rudder has a surprising number of small parts.  Most of them need to be cut apart from larger partially CNC’c parts and then trimmed or smoothed to fine angles to fit inside the trailing edge. I got most of the parts cut out and rough smoothed on my belt sander.  It did a great job in quickly grinding off the little tabs left over from the cutting.  I did most of the bandsaw cutting by hand, but the stiffeners were a bit intimidating.  They need to be cut to a rather fine point.  My plan was to run them through the bandsaw to get them close and then use the belt sander to get them properly sized.  I remember another builder cleco’d his to a piece of wood and then ran it through the saw.  This worked well.  All the stiffeners have the same geometry at their point, so I only need two pairs of holes (left and right stiffeners).  Then I can work through the block of wood with my fingers safely away from the blade.  “We don’t have time for a trip to the emergency room,” my Mom always said!

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So, the parts are all found and roughly hewn from their blocks.  I still have a lot of deburring and smoothing to do before I get going next time, but at least I have a good start!

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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.

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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.

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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.

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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.

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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.

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(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.”)

Now I know why it takes so long to build an airplane… (VStab continued)

I spent President’s Day in the shop this week and made a lot of progress fitting the vertical stabilizer skin to the skeleton.  It went together fairly easily despite a warning in the instructions that you might have to play with the rib/spar alignment to get it to come together.  The nose ribs were the hardest to get right.  The radiusing helped a bit and then just a tiny straightening of the rib flanges finished the job.

The matched hole job is astounding.  Everything fit together very nicely.  As I added each cleco, everything pulled together.  I found that giving each one a tiny wiggle as I worked through the line, ensured that I had a tight and aligned fit against the ribs.  The nose ribs’ front hole is not prepunched, so you have to drill it through yourself.  I had to use a couple cleco side clamps to pull the rib flange close to the skin to get an accurate hole.  After a bit of finagling, I got the whole thing clamped together.

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You can also see the score lines where I used a soldering iron (rounded off tip!) to melt through the plastic along the rivet lines.  This leaves most of the protective coat in place to keep from marring the skin.  I’m going to paint, not polish so a few scratches won’t be a problem, but better to keep it as shiny as possible.

The next step was pretty easy.  I just had to match drill all the holes on both sides.  This meant removing a cleco, drilling the hole, and replacing the cleco.  Lucky for me, I’m a little bit ambidextrous, so I was able to pull the cleco with my left hand whilst running the air drill with my right.  It went pretty fast.  I had a drill stop on the bit to make sure I didn’t push the hole through the other side!

The new air compressor worked well, but it was so cold in the garage (15-20 F) that I had to use a heat gun to preheat the compressor block to make sure the oil wasn’t too viscous.  With 11 gallons of air @125PSI, it was able to do most of the holes (drill was running at 40 PSI).  I had to recycle the compressor once to top it off at the very end.

Then the instructions ask you to do the most depressing thing.  Take it all apart!

You need to remove the burrs and chips that inevitably get made as you drill.  I also need to smooth the edges (to remove areas where cracks can start), prime, and dimple for the flush rivet heads.

I didn’t get a full day in on the next Saturday.  I went flying instead (a bit gusty, but good to get up again — the weather has been awful for flying), had a nice lunch with the wife (important to keep her happy), and helped a friend pack and move.  Despite all that, I did manage to get a couple hours in the shop.

The first point of order was to unclamp and prep the skin.  I started pulling clecos out and pulling of the plastic.  I had to deburr the holes.  I’ve ordered an adaptor so I can run a deburring bit in an electric screwdriver, but it didn’t arrive yet, so I’m hand deburring for now. You move the tool from hole to hole, slide the guide pin in and give it a gentle turn.  The interwebs are full of stories of people pulling too much metal off.  You just need to pull the slightest amount to remove the rough edge.  Here’s a picture of me tipping the tool into one of the 100+ holes (both sides!) that need deburring in the skin.

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I’m priming, so the entire inside coating has to come off.  Some of the ink from the coating comes off on the skin, but when I prep it for priming, it will come right off.  I’ve done this one as a selfie since the common wisdom indicates that the build log should show that I built it myself rather than contracting out the fun.

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The skin is awkwardly large, so it is hard to final polish the edges.  I tried using the scotchbrite wheel on the bench grinder, but it was too difficult.  I was sure to mangle the skin.  In the end, I used my smooth file (and the bastard file for a couple of rough spots) and a piece of scotchbrite pad to polish it out.  In the end, the edge has a bit of a “wavy” feel, but at least it is continuous and differentiable rather than piecewise smooth (math joke).

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I was tempted to prime the skin, but I ran out of time.  I always make my mistakes in the last 10 minutes of a session, so I opted to wait.  I did, at least, get a chance to check out my paint warming system.  The primer does not go on well when it and the metal are below freezing.  I bought a cheap hot water bottle and heated some water in the microwave to make a little hohlraum (physics joke) for warming the rattle can and my rivets.  I suspect at least part of my squeezing problem lay in trying to drive them at 10 degrees F.

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Next up: Priming and dimpling the skin.  Deburring, smoothing, and priming the ribs/spars.  Countersinking the spars.  Then riveting it all together!

 

Working on the vertical stabilizer

After my drill out problem with the vstab’s forward spar, I backed up and redid the two messed up parts.  Van’s support said that I would be OK with a relief rivet drilled and countersunk next to the original hole (with a caveat of carefully checking for cracks on each condition inspection).  For $30, it was easy enough to order replacement parts and try it again.

So the forward spar was easy enough to assemble, but the rear spar has a lot more going on.  It has a beefy doubler plate running about 2/3 of the way up the spar.  It also has 3 sets of hinges to install.  I got everything lined up and cleco’d together and then did the match drilling.  This was pretty easy, but with my good air compressor offline (I just returned it and will get a 20 gallon replacement model), I was using my 2 gallon oil-free compressor.  Oil free is nice because it is low maintenance and cheap, but it makes up with it by being incredibly loud.  I was wearing my ear protection the whole time, but it was still noisy.  Probably angering the neighbors!  I’ll have my new compressor online soon.

 

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The hinges are in identical pairs.  The arrows will help me remember (literally) which way is up!  Here, the hinges get match drilled through the hinge, the doubler, and the spar.  Not much metal removed, mostly just enamel that leaked into the hinge when it was painted.  I’ll give the hinge a quick spray of primer to cover the bare metal inside when I get around to priming.

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The plans ask (rather quietly) to radius the flanges on the nose ribs.  This is to avoid faceting where the skin stretches over a sharp bend in the flange and kinks.  I used my bastard file and a fine file to taper down and radius out the edges.

 

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The basic skeleton is fit together with cleco’s.  A careful observer will note that the tip rib is upside down! (I fixed it after the picture was taken).    The next steps are to final drill the rib attachment holes and to test fit (and drill) the skin.  This is a little tricky because there are several holes that will not get rivets at this step (to handle fiberglass fairings that go on later).

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After the test fit, there is still *lots* to do.  I will need to take everything apart.  Finish the deburring and dimple all the holes for the flush rivets.  And I need to prime all the interior parts (and the inside of the skin).  Then the fun begins!