Category Archives: ProSeal

A day of dimpling

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When I left off last week, I had dimpled the #8 screw holes and hadn’t yet started in on the 3/32″ skin holes.  There are a lot of them!  Because of the way the tank skin is bent, I needed to do some work getting my DRDT-2 set up.  In New York, I had a nice bench with an overhang set up permanently against the garage wall.  For most work here in Texas, I can get away with bolting my dimpler to one of the EAA work tables.  For the leading edge and tank skins, I need a bit of an overhang.  I thought of a bunch of possible ways to set this up.  In the end, I did something very simple and effective.  I used some 3.5″ x 5/16″ lag screws and a piece of 2×6.  This very solidly tied the extension into the table.  A couple of 1″ lag screws holds the dimpler to the 2×6.  It worked very well.

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So I sat in the comfy chair and twirled a dull drill bit in the holes.  I like this method. It is very fast and easy to control.  It just barely takes off the burr while leaving the hole nice and smooth.

I had high hopes of getting in some practice touch and goes, but all thoughts of that were quickly dashed.  It really poured! Even when the airport was in the clear, there were nasty thunderstorms lurking all around all day long.

The DRDT-2 and the carpet covered boxes worked vey nicely.  The dimpling went quickly, but there were still SOOOO many of them!  I finally got all of them done…

Next, I worked on the fuel caps.  There’s a pretty red anodized base and a cheap looking plastic sealing cap. I can get replacement ones made out of machined aluminum, but at $145, it is pretty pricy.  I don’t like the idea of painting the plastic though.  Will likely defer until it is time to paint the plane.  There are some steps, that I’m really excited to get to.   One of them is this shot of the fuel cap base clecoed in.  Pro-seal time is close at hand!

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One clever hint I saw is to set up a swiveling base for the stands.  The Pro-seal is messy and hard to work with on a good day.  These swivels will let me rotate the tank so that I have a good (better?) angle for both applying the sealant and for riveting.  Not quite done in this picture.  I cut these pieces from the end of the 2×6 I used to support the DRDT-2.  Added a rounded edge and then drilled them out for a 5/16″ hex bolt for the axle. We’ll see how they work soon enough.

Next time, I have a few non-Pro-seal tasks to finish on the tank attach brackets and shims. Standard trim, deburr, prime (just the external parts), and rivet.  If I get really saucy, I’ll do the nut plates on the inboard rib (screws pull in the fuel lever sender.  No gasket, only more tank sealant).  If I’m super productive, I’ll do the first set of sealant tasks (closing the tooling holes and adding the fuel flanges and anti-rotation plate).

Lots of work, but somehow the tanks look the same!

I’m finally back from my month long hiatus.  Some things went as planned, but I didn’t get as much flying in as I hoped.  I had hoped to fly to Fredericksburg for Memorial Day weekend, but the strong area wide thunderstorms put a crimp in those plans.  Somehow in a battle between an 865 pound plane and a Texas thunderstorm, I know who will win!

I did make it up to Denton, TX for my LSA-Inspector course.  I learned a lot.  Much of the course was about how to correctly fill out paperwork to keep the FAA happy, but there was a bit of hands on work.  There was a 60 question test at the end of second day.  I aced it, of course, as it was just a bit of memorization.  This didn’t actually get me my certificate.  I had to go down to the Houston FSDO (Flight Service District Office) to get someone to look at my paperwork in person and get me a temporary certificate.  I’ll get a new Wilbur and Orville FAA card in the mail in a couple of weeks.  I don’t actually need it to work on the plane, but will need it in October when I sign off the condition inspection for N903EN.

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My sister-in-law keeps digging up some of my father-in-law’s old tools (he built a BD-4 and most of a BD-5).  This time, she found a rivet puller and some Avex rivets.

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The last time I took the -12 out, I got a message on the EFIS warning me that the backup battery needed to be tested (It has an internal timer that makes sure the battery is tested once a year).  The test is really simple, actually.  When you shut the EFIS down there’s a button to run a battery test.  The way it tests that the battery will stay up for 45 minutes is to simply keep the display on for 45 minutes and see if there is still battery power remaining.  It passed with flying colors.  I’m good for another year.


2017-06-17 12.33.12 HDRI left off last time after getting some of the countersinks done for the tank baffle on the left tank.  I finished off the other 150 countersinks and then started working down the instructions.  Next up was prepping the #8 screw dimples and putting a slight bend in the trailing edges so they hold down better.  I really like these Avery pliers to do that.

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Then I finished up the J-stiffeners.  Just had to unclamp them, deburr, and dimple.

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The instructions suggest using a C-frame to do these #8 dimples as they will come out “crisper” than if you squeeze them.  I used the C-frame on the trailing edges, but ended up squeezing the side ones.

I still have to dimple the interior 3/32″ holes for the ribs, but I need to build an extension for my DRDT-2 for that.

So, I’ll need to make a quick stop at Lowe’s aviation department and get a little lumber so that I can run the dimpler off the edge of one of my EAA tables.  Once that’s done, there are a couple of outside pieces to finish up (countersinking the fuel cap, installing some shims, etc…) and then it’s on to the sealant!  Luckily, my hangar neighbor John used the stuff as an Air Force crew chief, so I’ll have some of his expertise to lean on.

I can hardly wait to get the tanks sealed up since things will happen fast after that.  I will finish up the leading edges (just have to put the landing light lens in) and start installing stuff on the wings.  My fuselage is ordered and should be here in early August!


Stiffeners and Tank Brackets

With my wife out of town for ten days, it was time to put some serious time in at the shop!  The tanks have many, many stiffeners that need to be finished off.  I rough shaped the pieces with a file and sander and finished on the ScotchBrite wheel.

Then all the holes have to be dimpled!  Careful to get them the right way!

Next up are the Z brackets that hold the tank to the spar. A lot of the part prep work is done before separating the pieces.  You ream to final size and make all the countersinks right on the whole bar.

Then it was time to cut the pieces apart.  The stock is pretty heavy, so I used the bandsaw.  Then I used a bastard file to trim the roughest part of the edge before finishing the piece on the belt sander (bulk) and ScotchBrite wheel (final).


My buddy Carver showed up to help.  He had been thinking about building an RV-12 or -14 as well (which is how he ended up wandering into my shop in the first place), but now he’s thinking about a Zenith Sport Cruiser.  That’s a nice plane too!  Not super zippy, but it is much easier to build and can haul a lot of stuff into some shorter strips.

I set him up working on the J stiffeners.  You drill one carefully measured hole at the end and then work your way across the tank.  He is not a “tool” guy, so I showed him how to use a marking gauge to measure from the end and a punch to start the hole.  Then we got the stiffener lined up and drilled the other holes.

I worked on prepping the Z-brackets.  The orange tape masked out the connecting surface with the tank (as it will get proseal).

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Carver had a bunch of “honey-do’s” to get to so he headed out while I kept plugging away at the Z-brackets.  All but two of them get 3 nutplates each.  So I started working through the pile until I had them all riveted. up.

Then we get to work on the tank skin.  Most of the skin parts are delivered ready to edge finish.  The tank skins still had some considerable tabs left.  I took them flat with the bastard file and then finished dressing the edge with sandpaper and ScotchBrite.

At this point, the tank baffle is inserted and cleco’d in place.  We need to counter sink all the holes.  Every 10th hole is left in its pristine state.  When we finally proseal this in place, the un-countersunk holes serve as a strong anchor to align the baffle.  We wait for the sealant to set up and then do a quick countersink on those holes.  I checked each hole with a rivet to make sure it was just barely flush.  I’ve got the countersink totally dialed in now (good as I have another 100 holes to go!).

So here’s one tank.  J-stiffener in place.  Baffle countersunk (one side).

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I’ll be taking a month long break from building at this point.  The next three weekends are full up.  My wife is back from her trip and it’s her birthday.  That means a straight zero chance of getting out to the airport.  Then we’re taking a trip out to Fredericksburg for Memorial Day Weekend (cool 1942 USO Swing Dance).  Then, I’m finally taking the course so I can get my Light Sport Repairman Inspector rating (to sign off on inspections for the RV-12). When I finally have a chance to get back to the shop, I’ll pick back up on the countersinking.  At that point, it will start to get real!  I’ll be mixing proseal and gluing up parts!

Tank time!

I headed down to the shop a little early this Saturday.  There was a front coming through in the afternoon and I wanted to get some more flying time in with the -12.  My neighbor was in his hangar banging away at his Rans, so I invited him along for the ride.  Just up for 45 minutes or so.  There was a scattered, low cloud deck at 1700′, so I didn’t go very far.  Some practice with the navigation system and playing around with turns.

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I still had a little deconstruction work to do on the bad aileron.  I got the thing pretty much apart and salvaged the nose ribs and end ribs.  After breaking off the manufactured heads, I still had to remove some of the shop heads.  I didn’t want to drive them through (which might bend the flanges here), so I just used a pair of pliers to rotate them out. The replacement parts will be here Thursday, so I can start the rebuild then.

When I packed up the shop, I roughly clecoed the ribs into the fuel tanks.  This kept the pieces together and kept the skins from getting banged up.  I wrapped the whole thing in moving blankets and slipped it into the spar crate.  Worked wonders for two moves!

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I had skipped the fuel tank section because I wanted to do the work when the weather was better. Not fun using fuel tank sealant, and really not fun using it in very cold weather!  So, first I started looking for parts.  The tanks have a surprisingly large number of parts!


I quickly found and sorted the main ribs.  The inner ribs have a large hole in the bottom so that fuel can run between the ribs.  I’ll probably put in a flapper door that helps keep the fuel inboard when maneuvering.  The outside ribs, of course, don’t have the holes. I quickly found the brackets and the stiffeners, but it took a while to dig out the flanges and fittings (hidden in a small brown paper bag labeled “Fuel Fittings”).  There was one part, though, that eluded me for almost an hour.  I couldn’t find the T1005A stiffener and clips.  I checked all over the hangar.  Finally, just as I was about to give up, I found it in the parts cabinet.  It’s an bent L, only about 1 foot long.  It had slipped to the back of the shelf and was mostly hidden.  I think I have all the parts now!

My buddy Carver is coming over next week to help (He’s at Sun ‘n Fun this week looking at planes!).  It will be nice to have more hands to do the parts prep.  Just gotta remember not to prime anything!

Almost an elevator, but not quite!


This blog has been dark for a long time.  I’ve still been working on the plane, but at a reduced pace.  A lot of my time was spent on “honey-do” lists.  I patched and painted the living room (3 colors), the dining room (3 colors), and the garage (2 colors + primer work).  I managed to find time to cycle in the New York Century (I went for the 80 mile ride, not the 110 mile one this year). I also snuck in a 6 day trip to finish my instrument ticket (got it!).  Made it to family day to visit my daughter off at college. Then a quick weekend trip out to visit my Dad on the West Coast.  I also started a machine learning class online and have been working on a startup idea with my sister.

When I last posted, the elevator was still in a million pieces (well dozens anyway).  It is now much further along.  Here’s the journey.

6 September:

At last, the ribs start getting reattached to the spars. You need to take some care to get the orientation correct between the left and right elevators.  I had one set up on each of my two tables (left and right) and did a lot of double checking to make sure things lined up.

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Next, the counterbalance skins get riveted to the the tip ribs.  The fit is pretty tight.  You start at the tip and work backwards.  The instructions said to check for twist.  Mine seem to have come out pretty straight.  I’ll know for sure when these get mounted on the horizontal stabilizer.

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The hinge for the trim tab goes on the left elevator.  I used my longeron yoke to avoid deforming the hinge eyes.  The blue tape marks a few holes that get riveted later in the final close out.

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Then, it’s a bunch of back riveting.  The ribs and spars get riveted to the skins.  This is where the genius of the split ribs shows.  My 5 foot back rivet bar was really handy here.  I did, however, miss the bar on a rivet on each of the elevators. The dent isn’t too bad.

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The bracket for the trim motor also get’s riveted in.  5 of the nut plates were riveted in earlier, but two get riveted in now (the two golden pairs of rivets.  It came out pretty nice.2014-09-06 16.29.14

So I ended the day with some skins, ribs, and spars riveted together.  It still doesn’t look that much like an elevator though.

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4 October:

It’s finally time to to put the skins together.  The split ribs get joined with some pull rivets.  It’s a tight fit, but the gaps are clearly designed to be big enough to fit the squeezer.  The instructions have some hints if the puller can’t quite get enough leverage to make the final pull, but I didn’t have any problems.

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Here’s a shot looking back from the trim bracket on the left elevator:

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Next up is riveting the rear spar using the “special” bucking bar.  The instructions tell you how to fabricate one, but I bought mine a couple months ago when it became clear that I would need one (from reading other people’s empennage blogs).  I was really worried that it would be hard to use, but in fact it worked great!  Do remember to shim as indicated.  It took a little positioning to get the bar stable, but I found it pretty easy to make sure that the bar was pushing up the correct rivet.  I hit it with a short burst to get it partially set, then I could lean more aggressively on the bar.

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Not too shabby!

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I used my 4″ thin nose yoke to squeeze the rivets for the front spar.  It was just enough to reach around the leading edge and made quick work of this task.  My back rivet bar worked really well to hold everything in place (the instructions ask you to used a weighted bar to hold the work flat here).

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The shear clips and other final bits also get riveted here.  My tungsten bucking bar (with a lot of tape wrappings) fit in here perfectly.

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11 October:

The next steps are all part of the final close-out.  The root and tip ribs get riveted into place.  Here, I just hung the elevator over the end of the table and hit both sides with the squeezer.

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These two that bound the skins with the end of the counterbalance skin were a real pain.  I did not read the instructions closely here and I could have substituted pull rivets.  It would have been much easier.  I managed to drive these rivets by slipping my tungsten bucking bar into the unclosed end and holding it through a lightening hole.  Pull rivets (at least on the bottom) would have been a better call.  They came out OK though.

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Finally, we finish closing out the rest of the easy rivets.  There are still a few open ones getting ready for installing the trailing edges.

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18 October:


The first problem to deal with was a stuck die.  This flat die was impossibly stuck in my pneumatic squeezer.  I tried just about everything to get it out.  WD-40, a vice, pliers… I just could not get it to loosen.  Finally, I put a grinding wheel back into my bench grinder and polished off a couple of square ends.  Finally, I was able to get a grip on the thing and pull it out.  I probably spent an hour on this.  Sigh.

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With that done, I could finally get the last of the rivets on the front spar on the right elevator.  It almost looks done! (but still lots to go)

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Time to prep the trim tab.  If you remember, I left it incomplete so I could ProSeal all of the ribs in one batch.  The first step is to tape and rivet the trailing edge.  Unlike the elevators, you rivet the trailing edge first and then slip the foam ribs above the spar.

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I used the recommended super sticky tape this time instead of epoxy or ProSeal.  If I had read the instructions more carefully, I would have put the tape on the trailing edge instead of the skin.  This worked fine, but it was more of a hassle trying to pull the tape over the dimples.

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I clecoed the trailing edge into the aluminum angle that I used for the rudder trailing edge (same spacing) to get everything lined up and bonded.  Then I broke out the back rivet bar and did the double flush trick.  It came out very clean.  At this point, the tab is ready for the ribs, so I set it aside.  You need to do all the ribs and riveting in one go and then set it aside for a few days, so I wanted to have it all prepped for the next step.

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The last step before gluing the ribs in the elevators is to add the double sided tape to the trailing edges and cleco.  Then set everything aside for a couple of days to help the tape stick better.  My plan was to come back one night in a couple of days and do the nasty gluing step. So, with everything clecoed in place and with the small ProSeal containers out, I let the tape set up.

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20 October:

I came home from work and hurried over to the shop to glue in the ribs for a rare weeknight build session.  In retrospect, I should have eaten dinner.  I figured this would take a couple hours max and then I would have a late dinner with my wife and son.  This is not how it went.

I wanted to have everything as ready to go as I could.  I got all the ribs out and placed near where they were to go and the rivets for the trim tab (the trailing edge is riveted after the ProSeal sets).  I wore 3 pairs of gloves so I could pull off a set if they became fouled with ProSeal.

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I mixed up my first batch of ProSeal.  It was pretty nasty smelling.  This was the small 1oz package.  It sets up faster than the normal sealant, but the garage was cool, so it wasn’t a problem.  I had purchased two of them (good call) because I wasn’t sure how far an ounce would go.  You add the pre-measured catalyst packet to the base and mix until it is a uniform grey.  It smells pretty nasty and sticks to everything.  The trim tab ribs went in pretty easily.  You need to push hard enough to get them to seat, but the thin layer of sealant lubricates it enough to slide pretty easily.  Then rivet the hinge to the spar and pull some rivets on the sides and you’re done — right?  Not so fast.  I didn’t have the pressure set well in my squeezer and had a hard time getting the rivets set (I pulled off my first set of gloves to get this done).  Then I went to pull the rivets for the close out tabs.  I pulled the first side and then one in the second side when I noticed that I put the bottom tab on the outside instead of the inside!  At this point my wife calls to ask if I’m headed home for dinner.  I brusquely tell her to go without me as I’ll be fixing my screw-up!  I had to drill out a couple of rivets on the spar and all of the pull rivets.  One spun instead of drilled and it was pretty hard to drill out, but I got it (A couple weeks later, when I picked up the trim tab, I could hear the drilled out end of the rivet rattling around inside!  Luckily it fell out the small drain gap near the trailing edge.  I really didn’t want to open it again!).

Eventually, I got the whole thing open enough to reset the close out tabs and put it all back together.

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Then I just added a board and some barbells to hold it flat while the sealant cured.

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I hurried to get to the next step before the sealant hardened (remember, I was using the quick setting variant).  You peel off the tape backing and hold the trailing edge open (this is why you don’t rivet quite all of the rivets to the root and tip ribs).  I used some pieces of 2×4 and 2×3 to hold it open.

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You can see how the rib (in the picture to the left above) sort of floats in the middle.  You slide the rib into the rear spar with a satisfying crunch that lets you know that it is in place.  If you don’t push it in enough, then the tip will interfere with the trailing edge.  Once the ribs were in place, I pulled out the wood blocks and clecoed everything.  I weighted the connection as called for (I used my back rivet plate, my vice, some of the lead counterweights, some barbells, pretty much anything heavy that I had laying around the house and garage).

The right elevator went much the same as the first.  I needed to mix up the second 1 ounce sealant package as the first was (1) running out and (2) hardening too fast.  Same deal with clecos and weights.  Finally, at about 9:20pm, it was all done.  The instructions say to let it go at least 3 days to cure.  It worked out to be a couple of weeks before I actually got around to riveting the trailing edges (though now our home garage looks really nice with a new coat of paint!).

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1 November:

I didn’t get much done today.  I was ready to double flush rivet the two trailing edges on the elevators, but my back rivet set jammed.  The little sliding collar just stopped sliding.  I tried lubricating it and sliding it by hand to get it unstuck, but a metal chip or something is preventing it from sliding freely.  So I gave up for the weekend, went home and painted the garage to help with marital harmony (and placed an order with Cleaveland Tools!).

I actually needed some other tools as well.  I got a couple of new #30 and #40 reamers, some new pin punches (the old ones were cheap and bent a little), and some safety wire pliers (and safety wire!), and a new 1/8″ acrylic drill bit (plastic bits have a very sharp point.  Very nice for starting a centered hole for rivet removal.  I dropped my drill with the old one and bent it).

8 November:

I finally double-flush riveted the two trailing edges on the elevator.  The left side came out so-so.  I removed a couple of the worst offending rivets and tried again.  Now it’s OK.  The right side came out pretty bad.  The heads are not sitting very flush at all.  I’m nearly out of 3-4.5 rivets (I ordered some more), so I’ll give it another try later.  It’s probably acceptable, but I want to do better as it’s a very visible rivet line.

Proceeding for now anyway.  The next step is to bend the hinge pin for the trim tab.  You need to make two very square bends.  I noted that a number of people have trouble with this task. Pliers are notoriously bad for this sort of thing and can really bugger up the pin.  Luckily! I have an 18″ Little Giant Bending Brake (yet another aircraft construction tool I picked up from my Father-In-Law.  Thanks Dad!).  It took a bit of mental work to figure out how to orient everything, but it is, in fact, quite simple to use.

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I cut an 18″ piece of angle bracket to fit the brake (Dad left me a clamp piece with angled edges, but I wanted something square for this step).  I put a groove in the bottom perpendicular to the edge to hold the hinge pin straight.  I had a Sharpie mark where I wanted the bend to go, but I didn’t have a good feel for how much allowance to make so I left it a little long.  The bend was very easy.  The mechanical advantage of even a small break made it a snap to get a clean bend.  It sprung back a little, so I re-clamped and bent it using the angle piece my father-in-law provided (you can see it in the picture below).  It hit pretty close to a 90 degree bend.  Then I measured for the second bend and did it again.  It looks just like in the plans!  I used a grinding wheel to get the final length right to .8 inches.  I then cut the long length and ground it smoothed.  I made the tip into a bit of a bullet shape to help with the next step.

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Then I had to slide the hinge pin into the hinge.  It’s a 32″ push!  The bullet nose helped.  I ran the pin through each individual side to make sure the hinge eyes lined up.  I had two that I had to make a slight adjustment to.  It took a couple of tries to get it through the whole hinge.  I used some Boelube on the tip and some WD-40 along the pin shaft to help it along.  It wasn’t as hard as I thought it would be.  For the final step, I had to add some safety wire to hold the pin in place.  You drill a small hole and then just wire it in place.  I watched a couple of You-tube videos to get a handle on how to use the pliers and went for it.  The pliers are really interesting.  They clamp on the wire and then spin freely when you pull a knob on the bottom.  This makes some very nice, tight turns.  I clipped the twisted wire off and bent it over to prevent snags.

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In the end, it came out really nice and looks just like the picture in the plans.

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The next step was to mount the trim tab motor to its bracket.  I got the final 3 aluminum parts out for the elevator and deburred and primed them.  I also had to dig out the right wiring harness and a molex connector.  It all went together really quickly.  Only a couple of hitches.

The trim tab push rod is too short.  This wasn’t anything I did, the actual part is too short!  I got a service bulletin saying that Vans would send me a new one.  It is coming with the wing kit in a couple of weeks.  I was planning on rebuilding it anyway because I didn’t think it provided enough clearance to swing freely on the trim arm.

The mounting plate is dimpled (for the screws of course), but the backing plate is not!  I went back through the instructions, but I did not see any mention of dimpling.  I may have to countersink the backing plate or just widen the holes enough to take the mounting plate.  None of my yokes fit into the holes.  The lore says to think ahead about how each hole is used and prep it accordingly because sometimes the instructions overlook something.  This is a case of that I suppose!


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So here’s the final view of the elevator.  Just need to roll the edges and take care of a few small tasks before it is on to the rear fuselage!

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The final steps for the elevators are:

  • figure out how to dimple the backing plate for the trim tab motor plate
  • roll the leading edges
  • wait for the new, longer trim tab pushrod to arrive (Vans Service Bulletin)
  • hang ’em on the trophy wall until it is time to attach them to the rear fuselage