Empennage

Well, that hoped-for long evening in the garage didn’t really happen.  I was still able to get a bit done, but I was limited by my need for (and therefore availability of) a helping hand.

I started with riveting the HS-707 nose rib on the starboard side.  I wanted to try my alternate method of starting with the forwardmost rivet, but that didn’t work as well as I’d hoped.  Even clecoing only the hole just aft of that pesky bugger, the rib didn’t want to sit flush against the skin.  Oh well.  So i went back to what I did before and started at the back, working my way forward.  I made a brief try at shooting these rivets solo, which was a bad idea.  The angle meant that I’d have to shoot with my left hand and buck with my right.  First rivet went great, but I somehow set the second one with the shop head sticking a good bit out of the skin.  I suspect that I had a tendency to put too much pressure on the bucking bar and not enough on the rivet gun..so yeah, left-handed riveting is apparently not wise.  I got that SOB drilled out-thankfully without damaging the skin- and waited for help on the rest.  Once Josie was able to help, we got the rest of the nose rib rivets set.  It was again getting late by this time, so I decided to clean up, cleco the front spar in place, and leave the rest for tomorrow.  

We’re going to be out of town again this weekend, so I feel compelled to make the most of of the weekday nights.  I was a little bummed that I didn’t get more done tonight, but things are still coming together.  After a lot of head-banging, some ruined parts, and lots of steps forward and backward, I finally have something nearing a finished airplane part.

Josie grabbed a photo of me clecoing everything together so I could jump right back in tomorrow evening (I seem to be concentrating really hard!):

Short version: the first major assembly of my RV is DONE!

First task of the day was to get the front spar blind riveted to the HS-707 and -708 ribs.  Easy enough, then it was on to riveting the front spar to the skin, followed by the HS-708 main rib.  Not too bad here either; I’m starting to get a pretty good feel for bucking rivets without a lot of hit-check-hit some more-check again-etc.  I did get a little overconfident though…had a couple of bad rivets, but I’m also getting pretty good at drilling out.  Not perfect though-I did have one hole I enlarged.  No worries though-I drilled out to #30 and dipped into my supply of oops rivets.

I also noticed a change in my attitude as I was working today.  Previously, if I fouled up a rivet or made some other mistake, I was prone to getting annoyed, stewing about it, beating myself up, and generally reacting in a nonproductive way.  Today, it was just businesslike: Bad rivet?  OK, drill it out and replace.  Instead of wasting time thinking about my foul-up, I’d fix it in five minutes and be on my way.

Anyway, with the front spar and main rib set, next step was to cleco the rear spar assembly in place, then rivet it and the visible ribs to the skin.  Nothing complex here, just a lot of squeezing.  (Side note: I played with a Cleaveland Tool “Main Squeeze” at Oshkosh.  Boy, I wish I’d had that thing today-makes squeezing so much easier…)  At this point, acording to the instructions, all I had left was to blind rivet the rear spar to the HS-708 main rib.  But there was still riveting left to do- the rear spar hadn’t been riveted to the HS-706 tip ribs.  Either I missed it in the instructions or it was left out…in any case, setting those four rivets was the last task to finish my stab!

Of course, this was where things went awry.  Since I had the squeezer out, I decided to squeeze these four rivets as well.  Yeah…squeezing -4 rivets is tough with full-strength hands, never mind hands that just got done squeezing probably 100+ -3 rivets.  The first two were passable, barely.  The last two were both totally jacked up.  To make matters worse, out of some sense of symmetry, I’d put the manufactured heads forward, where they were nearly impossible to access for drilling out.

After some head-scratching, I decided to get out my angle drill kit.  That let me get a decent shot at the heads, but it was impossible to tell if I was centered on the head.  I really didn’t want to foul up my holes on the home stretch…so I decided to drill out with a smaller (#40) bit to help avoid getting any of the rib/spar material.  This worked mostly like a charm-I didn’t damage any holes, though getting those rivets out was a bear.

Finally, I set those four rivets again, using the gun this time. Much better.  Then I sat back and realized that I had a completed horizontal stab sitting right in front of me.  Lots of false starts along the way, but I got past it all and finished a part!  Now on to the next part, and the next, and so on…there’s a lot left to build!

Squeezing rivets…over and over and over:

It’s DONE!

And now I have my first airplane part hanging from the ceiling:

Wow, I really went two weeks without working on this thing.  I had an excuse for last weekend-I was out of town-but the rest of it, well, I’ve got nothing.  I think part of the problem was that the sense of accomplishment when I finished the h-stab made my brain go into “finished” mode.  It was almost like going back out and working on the v-stab was like starting a new project.  But anyway, I finally got back to work today.

The good news is that the next component, the vertical stab, has a fair amount of work into it already and, barring any obstacles, could be done pretty quickly.  Previously, I’d gotten almost all the skeleton work done, with the exception of some annoying rivets.  Along the way, I’d damaged the root nose rib and decided to order a new one.  So today, I started out by drilling out the one good rivet I had and removing the old nose rib.  Then I had to prep the new rib…nothing exciting here, match-drilling, dimpling, edge finishing, prepping for primer, priming.  Easy.

Of course, there were some necessary waiting periods in there while the cleaned rib dried, and between coats of primer.  I used this time to fix the figure-8 dimple I put in the v-stab skin way back when.  I used the rivet gun with flush set and my back rivet plate to pound the dimple flat, cleaned up the edges of the extra hole, redimpled, and checked for cracks.  A good deburr and it was time for an epoxy patch.

That only took up one waiting period, so I next went back to the rudder I started on, also way back when.  I had one hole that needed an oops rivet; I clamped the stiffener in place, drilled to #30, deburred, no biggie.  I then set about back riveting the stiffeners on the starboard side.  Since I didn’t have a helper out in the garage today, I left the three trailing rivets on each stiffener undone; I want a second set of hands to hold the skin out of the way while I do those.

Oh hey, primer’s dry!  Let’s see if we can get this skeleton riveted together finally.  Those who have been following along know that I had a lot of frustration riveting this before.  I’d like to tell you that there was no frustration tonight, but that would be a horrible lie.  I did get the center rivet bucked on the second try.  Then I proceeded to foul up both end rivets.  Then I proceeded to bend the rib flange a bit while drilling those out.  Then it was quitting time. (Josie and I are going out tonight)  I’m not sure at this point if the nose rib can be saved; I’ll have to drill out that good center rivet and pull things apart again to see if I can straighten the flange acceptably.

So yeah, I got a fair amount done today, but I’m back in the land of frustration with these same three rivets.  Maybe it’s time to cough up for a Cleavaland Main Squeeze- I tried one at Oshkosh and it was truly an amazing tool.  With a no-hole yoke, I think I could squeeze these without a lot of problem; and given the low effort of the Main Squeeze, I’ll be a lot less likely to twist the squeezer while squeezing.  Hooray for more tool spending!

For those of you that sat through all this, your reward is a picture of me getting ready to drill out a rivet:

Brief summary: Time to order more parts.  I started today by pulling the VS-704 and -705 ribs off the v-stab spar, flattening the bent flanges, and then inspecting them.  There were indeed some holes that were a bit oversize.  Just for fun, I reassembled the skeleton in the v-stab skin, and found that the now-oversize holes don’t exactly line up, presumably due to all the bending/rebending/etc.  So I’ve decided to replace both the ribs as well as the VS-702 forward spar.  In a way, it’s just as well…I wasn’t going to try riveting that pesky spot again until I got my new squeezer, so I might as well wait for new parts while I’m also waiting for new tools.

In keeping with my new habit of “stop sulking about broken stuff and get back to work,” I moved back to working on the rudder.  Yesterday I’d back riveted the stiffeners on the starboard side, with the exception of the three rivets closest to the trailing edge. (I wanted a second set of hands to hold the skin out of the way while I did those)  I had help available today, but didn’t want to trouble her unnecessarily, so I decided to go ahead and repeat this task on the port side.  Then I could just recruit Josie for 15-20 minutes, and wrap up the back riveting.  Flawless plan!

Well, not quite.  Most of the back riveting went great; it really is a technique that makes things go fast without compromising quality.  But then the time came to hit those rivets on the trailing edge.  What I didn’t think about was what might happen with all the stiffeners in place, but the trailing edges not secured.  When we started and Josie held the skin back, the trailing ends of the stiffeners on her side of the skin popped out, thus getting all up in my way again.  We had to improvise a bit; on the first side of the skin, I hit all but the aft-most rivet on each stiffener, which was the one that was really interfered with by the opposite stiffeners popping out.  We then flipped the skin, and I was able to hit all the rivets; with just that one rivet on each stiffener unbucked, interference wasn’t a problem.  Then we flipped once more and I hit up those last rivets.

So there’s a lesson for when I get to the elevators…finish the stiffeners on one side completely before going to the other side.  Sometimes plans for efficiency can have the exact opposite effect.

At this point, the next step was to bend the trailing edge.  The rudder skin comes pre-bent, but only partially.  This gives the builder room to get in there and rivet the stiffeners; once those are in place, the trailing edge is bent to the “final” degree.  Doing this bend requires a homemade bending brake, which is just a couple 2×8 pieces attached with hinges.  The trailing edge goes between the planks, they get squeezed together, and the end result is a nice bend.

I didn’t have the materials, so a quick trip to Lowe’s before they closed was called for. (plus it was way past time for dinner)  Back home, the brake went together in no time.  I clamped the brake to the workbench, laid the skin in place, supported the other end of the skin with some 2×4 scrap, and then clamped the skin down to keep it from moving.  Josie came back out to help and we got the bend done in no time. (I was so excited that I forgot to get pictures of the brake setup!)  I then clecoed the spar and ribs into place to check the trailing edge for straightness…it looks GREAT!

I was kind of surprised how easy the bend was.  I’d done some reading on the procedure beforehand, and found a guy who claimed to have agonized over getting this bend right for weeks.  I guess I can see how this bend is a real commitment, where a mistake means it’s time to start over, but on the other hand the bending setup is pretty elementary.

I wrapped up the evening by reading ahead in the rudder instructions and trying to visualize how the parts will go together.  I’m anxious to keep rolling on this, but other things will probably get in the way.  There’s a big deadline approaching at work, and we’ve been put on notice that there will most likely be some long days ahead this week…so I’m not sure if I’ll be able to get much, if any, time in the garage until next weekend.  Still, despite the setbacks I’ve had with the v-stab, I’m still making forward progress and getting things done.  I could work faster and be more productive, but the truth is it’ll be another month or two before I can order the wing kit, which in turn has an eight-week lead time.  So no matter what, I probably won’t have my wing kit here until near the end of the year.

Rudder skin with stiffeners in place: (note how wide the bend is compared to the next photo)

Freshly bent skin with spar and ribs installed:

Yup, last week went pretty much as I expected at work.  Not much time for working in the garage until today.  Anyways, today’s first order of business was to fabricate a couple parts.  The plans call for R-716 and -717, a spacer piece and rudder bottom attach strips respectively, but these pieces aren’t included in the kit.  Turns out this is what the previously-mysterious “trim bundle” is for; it’s some pieces of alclad sheet of various sizes and thicknesses.  I found the appropriate pieces of aluminum, and thanks to the wonders of my bandsaw, I had my pieces cut up in no time. (in fairness, they’re pretty simple)

Next up is trimming the notorious R-710 rudder horn brace.  This fits between the root rib and the control horn, but as supplied it needs some material removed.  From reading other builder’s notes, I learned that it’s a common problem to remove too much material here and end up with unsatisfactory edge distance.  There are holes marked for the trim line, but given the common problem, I didn’t trust them.  Instead I temporarily put the root rib and control horn together, then used them as a guide to mark my initial cut lines on the brace.  The snips made quick work of these cuts.  On my first test fit, I found I needed to remove more material, which is exactly what I wanted.  A few more trial fits and some work on the belt sander, and everything fit together nicely.

The next bit of fun was the R-703 tip rib.  This rib has an additional strip that wraps around it, which will eventually house the counterweight and serve as an attach point for the fiberglass tip fairing.  The directions provide the deceptively simple instruction to “flute the leading edge until the holes line up with the R-713 attach strip.” Well, try as I might with my fluting pliers, I could not flute that thing sufficiently enough to get those holes to align.  The pliers also made such a wide flute that by this point, the holes themselves were not flat any more. (something I learned today: I need better fluting pliers)  So I got out the hand seamers, straightened that flange, and tried to come up with an alternate solution that didn’t involve stopping for a few days to wait for new tools.  Eventually I built a jig of sorts out of scrap wood, with which I was able to make a much tighter flute and get everything lined up.  Whew!

Next up, the whole skeleton goes together and there’s a lot of match-drilling to be done between the various pieces.  Nothing complicated here, just semi-tedious work.  After this, the next thing was to clamp those attach strips I fabbed up earlier and get them drilled.  However, I have some plans tonight, so I decided this was a good point to call it a day and get inside for a shower.  It looks like I should be able to finish my prep work and get everything cleaned and primed tomorrow.  Not sure if I’ll get around to any riveting, but we’ll see!

I wasn’t too good with photos today.  All you get is this photo of the temporary rudder assembly, complete except for those attach strips:

Let’s get the bad news out of the way of the bat: you astute observers may have noticed that yes, I’ve switched components again and it’s back to the v-stab.  The short story is that in an extended moment of frustration working with the rudder counterweight skin, I kind of brute-forced things to get them to fit.  I knew when I did it that it wasn’t the best thing, and once I had a couple days to think about it, I decided that while it might have been OK, I didn’t want it on my plane.  Hooray, another replacement parts order for the folks at Van’s!

Fortunately, only a day or two later, my new parts for the v-stab came in.  This past weekend was mostly booked solid, but I had Labor Day off.  After sleeping in a bit to recover from a long weekend, I hit the garage running.  First order of business was to get the new parts ready to roll; after a good long session of match-drilling, dimpling, deburring, fluting, etc, that was covered.  Then it was out to the driveway to clean the parts prior to priming.  They dried quickly in the sun, out came the primer, and it was time for assembly.

Now, some of you might recall the very tough time I’ve had getting the root ribs riveted to the front spar.  I already re-ordered the nose rib once, then re-ruined it, along with the spar and main rib, prompting this most recent parts order.  But I also acquired a Main Squeeze rivet squeezer from Cleaveland Tool, along with a thin-nose yoke, figuring that this would help me get into the tight space and get those ribs riveted.  I’m pleased to report that I was correct.  Yes, I finally got those ribs riveted to the spar.  Re-riveting the other two ribs was a cakewalk, and wonder of wonders, it was finally time to start riveting the skin!

Riveting the h-stab was good practice for this; that taught me some good techniques for holding the bucking bar in the tight space inside the part.  The v-stab is actually thicker than the h-stab, so in a way it’s easier to do the riveting.  I made pretty short work of getting the hard-to-reach skin rivets done.  Then, I clecoed on the rear spar, which had been waiting patiently for about three months since I finished it. (I just looked back at that post, where I opined that I might be riveting the skin on in no time.  Pretty humorous in retrospect…)

I started working on the skin rivets on the edge, all of which can be reached with the squeezer.  I figured that I’d be able to knock these out, rivet the rear spar to the rest of the skeleton, and have myself another finished component.  But I ended up with some odd problems.  I botched one of the first rivets I set; the shop head is way too thin.  I think I somehow used the wrong length rivet.  Then things got weirder still.  I ran across several holes where the rivets simply wouldn’t sit flush with the skin.  I can only assume that way back when, some of these holes didn’t get dimpled enough.  Fun thing to find when all the stuff is mostly permanently assembled.  Luckily, I was able to clean up the shallow dimples I found by simply using the dimple dies in the squeezer and hitting the skin and skeleton together.  Maybe not the best way to do it, but at least the rivets sat flush.

I squeezed a number of rivets on one side, but a look at the clock made me decide to call it a night.  It was going on 10:30, and I knew I had a couple rivets to drill out later on, plus most likely some more work with the rivet gun, which the neighbors might not appreciate. (particularly since I was working with the garage door open today)  I could also feel myself starting to get a bit sloppy.  Plus, it’s an unwritten rule that, following completion of the v-stab, the builder must prop them on his workbench in the rough position they’ll sit on the aircraft and take a picture while grinning madly and holding the v-stab up.  Seeing as how my h-stab is hanging from the ceiling, I didn’t want to deal with taking it down. (and I knew that if I did finish the v-stab, I’d be unable to stop myself from getting it down for the photo op)

So I’ll go out tomorrow after work and finish this thing up.  And, of course, get the required photo.  Hopefully my new rudder parts come soon so I can keep working…not much reason to hurry right now, since the wing kit isn’t ordered yet, but I’m feeling some momentum and would like to capitalize on it.  I’m having fun out there!

The rivets that gave me so much trouble, finally tamed by the Main Squeeze:

Mostly assembled stab, waiting for a recuperated builder to finish it:

And yes, I really did finish it up after midnight.  More on that later…

All I had left to do today was to squeeze all the skin rivets around the perimeter of the stab, then use a combination of solid and blind rivets to attach the rear spar to the rest of the skeleton.  But first I had two bad flush rivets to drill out, a reminder of what happens when I keep working even after I get tired.  At one point, I thought I was getting pretty good at drilling out flush rivets without damaging the holes, but I must have backslidden, as I enlarged one of those two holes.  Oh well, that’s what I have the oops rivets for.  With those drill-outs out of the way, I proceeded to squeeze all those other skin rivets.  Well, almost all of them.

In general, there are some minor access issues working on the rear of the stab; the lower end of the spar web has a reinforcement riveted in, and where the skin rivets happen to be near a rivet in the reinforcement, the squeezer has to be placed carefully to ensure the shop head stay under the die.  Those weren’t too bad, but there were four that were a real pain.  As if the spar reinforcement isn’t bad enough, about midway up the spar are a set of rudder hinge brackets.  Yup, even less clearance. This was actually where I left off last night; my first attempt to squeeze one of these ended up with the shop head malformed due to slipping of the squeezer die.

Today I was much, much more careful, and I was able to get three of the four pesky rivets done with the Main Squeeze and my thin-nose yoke.  The fourth and last rivet was not so easy.  Despite careful positioning, I malformed another shop head.  Then I enlarged the hole drilling it out.  As if trying to squeeze a -3 rivet i there wasn’t bad enough, now I had to use an oops rivet with an even larger shank.  I wasn’t quite sure what to do with this, so I decided to move on to riveting the rear spar on.  That went pretty fast, but I had yet to come up with any ideas about that last skin rivet.  I decided to call it a night, maybe seek help on VAF, and finish tomorrow.

A couple hours later, I was still thinking about that pesky rivet.  It occurred to me that the shape of the die was really the problem; if I removed some material, I could get in the tight space better and get that thing squeezed.  But I wasn’t about to carve up my shiny new $150 yoke for the Main Squeeze.  Oh wait…why not just modify one of my flush rivet dies and use it with the old squeezer?  Worst case, I ruin a $20 die that’s easily replaceable.

So that’s how I ended up firing up the bench grinder at roughly 12:15 AM.  The modified die worked like a charm, and now I had the satisfaction of going to bed with the completed stab in my garage.  But first, I had to pull the horizontal stab down and set up the good old “pose-with-your-shiny-new-stabs” photo.

Kudos to Van’s for timing.  The day after I finished the vertical stab, a package showed up at my front door containing the replacement parts for the rudder.  I celebrated by waiting an additional another day before getting back to work.

This story actually starts on Thursday night, when I had my shortest night of work on the plane ever, at maybe ten minutes.  The first order of business was to redo the R-703/-713 alignment.  I was enthused right off the bat, because the new rib and counterweight skin seemed to not be as misaligned as the first set.  I got out my shiny new Avery fluting pliers and put a gentle flute in the forward flange of R-703.  I checked it against the counterweight skin…not quite.  I applied the pliers again with a bit more force, then checked…still not quite there.  One more time with the pliers, good amount of force this time…hmm, that “flute” looks very angular.  Oh great, I squeezed too hard and cracked the flange.

Given the difficulty I’d now had with two of these things, along with the potential self-loathing I’d feel if I ordered yet another tip rib, I decided to try something different.  My plan was to cut a relief in the middle of that flange, between the two rivet holes.  This would take care of two problems: first, it would completely excise that material I’d cracked, and it would also make it a lot easier to align the holes with the counterweight skin.  It didn’t seem to me like this would compromise strength, but I figured it was prudent to solicit second opinions.  So I asked the great community at VAF what they thought of my idea.  No objections, and one guy had the good idea to add a doubler if I was worried about strength; I decided the doubler was an excellent idea.

Back out in the garage today, I put my plan into action.  I knew that the base of my relief cut needed to be radiused properly to avoid stress concentration, so I decided to start my work there.  I marked out a decent centerline, centerpunched a hole, and drilled it to 3/16″.  Then I marked my cut lines, and the bandsaw made quick work of those.  A cutting bit on my Dremel cleaned up the transition between the bandsaw cuts and the drilled hole, and I finished by dressing the cut edges.  Next I clecoed the counterweight skin in place before rough-cutting a strip of .032 alclad for the doubler.  Clamped that in place (making sure the strip followed the curve of the flange), drilled through the two holes, cleaned up the doubler, and everything was good to go again.

After match-drilling the new rib to the rudder skin, the only thing left was to drill the R-717 attach strips I fabricated a while back.  These strips sit inside the root rib, and they’re drilled by clamping them into place and using the skin and rib as a drill guide.  Slight problem here is that the rib and skin obviously need to be aligned properly for this to work right, but trying to align three sheets and clamp them together isn’t exactly easy.  My “solution” (if you want to give it that much credit) was to cleco the skin to the rib on one side for general alignment, then clamp the attach strip to the other side for drilling.  Worked like a charm.

After that, the rudder came apart and there was deburring-aplenty to be done.  One decent-sized pile of metal shavings later, I was thinking of calling it a night, but decided to get the skeleton pieces dimpled.  This way, on my next work day, I can move right into prepping and priming.  Dimpling went great until I got to the narrow ends of the tip and root rib.  I knew ahead of time that these were tight spaces that would need special tools, so the last time I ordered from Cleaveland, I made sure to order their pop-rivet dimple die sets.  At the time I clapped myself on the back for planning ahead.  Tonight, I discovered that there wasn’t even enough room to get the mandrel for that dimple die set in there.  ARGH!  After some head-scratching, I came up with a solution: I cut down one of the mandrels, only using it to position the small dimple dies in the rivet hole.  Then I was able to get my Main Squeeze with the thin yoke around them, and viola!  Nice little dimples!

I have plans tomorrow afternoon, but I’m hoping maybe I can get out before that and get these pieces prepped and primed tomorrow.  I also still need to dimple and otherwise prep the rudder skin, but I can easily do that between cots of primer.  Assuming I can get things primed tomorrow, I don’t think it’s out of line at all to think I can have the rudder done this weekend. (I should know better by now than to count my pre-hatching chickens like this, but I just can’t help it…)

Here’s that pesky tip rib after I made my relief cut: (edges still haven’t been finished at this point)

And here it is with the counterweight skin and fabbed doubler clecoed in place:

And here’s a small pile of parts waiting to be deburred:

No priming today.  My paint booth (aka driveway) was intermittently rained out.  So instead I just cleaned and prepped all the skeleton pieces.  This way tomorrow I can go straight into priming and see where things go from there.

I did not, in fact, get the rudder completely riveted today.  I’m starting to think that it might be fun to keep track of every time I say “I’m pretty sure I can get XYZ done tomorrow evening” and I end up being horribly wrong.  I guess it’s a good thing that I’m amused by this instead of being annoyed.

Weather was good this morning, so I was able to get the parts primed.  I also still had to finish deburring and dimpling the rudder skin; I figured I could effectively multitask these things, and it worked pretty well.  Put some pieces on my priming board, shoot primer, go inside and deburr a couple edges, back out to the driveway, shoot more primer on any thin spots, back inside, etc.  In this way I had all the deburring done by the time all the skeleton parts were primed.  The only unexpected thing that came up during this time was drilling the holes for the leading edge of the rudder.

The instructions don’t mention anything specific about final or match-drilling these holes, but since (to my knowledge) all of the fastener holes are undersized from the factory, I figured that they would probably need attention.  And since I was already deburring holes, it would be easier to final drill them and deburr them the same time as everything else, unless there was some compelling reason to wait.  I checked the prepunched holes against the called-out blind rivet-yep, definitely undersized.  So I went ahead and final-drilled them to #30.

Dimpling the skin-skeleton holes was the last step before starting assembly.  The instructions start with putting together the tip rib assembly; first riveting the counterweight skin on before fitting the rudder counterweight.  Here, I committed my first mistake of the day.  Since I had added the doubler on the leading edge after splitting that flange, I knew that I was going to have to figure out for myself the proper rivet length.  The plans called for an AD426-3.5 rivet, so I grabbed the next longer length, a -4, and dropped it into the hole.  The old Mark I eyeball said that the tail looked long enough, so I proceeded to squeeze it.  Hmm, looks a little small.  For some reason, my brain didn’t register that there was a problem until I squeezed the second one.  Even then, it didn’t sink in just how horribly undersize the shop heads were until I started squeezing the rest of the skin-rib rivets.  With proper shop heads to compare them to, it was painfully obvious how inadequate those two rivets were.

They don’t even cover the edge of the dimpled doubler:

At this point, I had to stop for a bit; Josie and I had plans to catch a one-time showing afternoon movie at a local theater, so I got in a shower and we departed for a few hours.  When I came back, I got those offending rivets drilled out and replaced with -4.5s.  Much better.

On to the counterweight itself.  The two mounting holes in the tip rib have to be enlarged to #12 and dimpled for a #10 screw, and the counterweight has to be countersunk under that same dimple.  Here I ran into another issue: in the tool list Van’s published, they list a dimple die for a #8 screw, but not a #10.  I sort of saw this coming; when I was researching some other issues a couple days ago, I found that other builders had run into this same problem.  Several folks had simply used the #8 dimple die, then enlarged the dimple to final size using the screw itself as a die and the countersunk weight underneath.  This worked well for me as well; I felt a little weird about doing this ghetto dimple, but hey, it works.

Now to start assembling the rest of the skeleton.  First up, I riveted the upper two reinforcement plates to the spar.  These are found at each point where the rudder hinges attach; there’s just a doubler plate as well as a nutplate which the rod end bearing which serves as the hinge mounts.  These were pretty easy, except for the part where I riveted the first nutplate to the wrong side of the spar.  I could have been mad, but in truth I actually found it hilarious, simply because it was such a dumb mistake.

Next up, the lower end of the skeleton, probably the most complex part of the assembly.  Lots of pieces are attached here: a spacer strip, the root rib, the lower reinforcement plate, the nutplate for the rod end, the rudder horn, an the rudder horn brace.  Following the instructions, I clecoed everything except for the horn brace into position.  Shooting all those rivets was pretty easy; next I slid the horn brace into position, and immediately realized this was going to be interesting.  There are four rivets between the brace and the horn, and one side of this joint is inside the brace, accessible only through the lightening hole in the brace.  How in the world was I going to squeeze solid rivets in there?  My squeezer wouldn’t reach in there; well, maybe with a longeron yoke, but I don’t have one of those.  Maybe I could buck in there if I had a small tungsten bucking bar, but…yeah, don’t have one of those either.

Then I consulted the plans again and found some useful information: it’s apparently acceptable to substitute LP4-3 blind rivets here.  Hooray, I’m no longer at an impasse!  That sense of jubilation didn’t last long…I only have two LP4-3 rivets from the hardware bags, and I need four.  Well, this is a good time to call it a night anyway.  I figured I’d order the required rivets from Spruce; they’d be here Tuesday and I’d hardly miss a beat.  Oh wait, Spruce doesn’t have this particular rivet.  But VAF came in handy again, as I learned that Cherry MSP-43 rivets are an acceptable substitute, and Spruce does have those.  

I also learned something else useful: Four skin rivets on each side at the root also have one side inside that horn brace.  The plans call out a CS4-4 blind rivet as an acceptable option, which sounds good to me.  What I hadn’t thought about until I read some posts on the subject is that those are -4 rivets, and thus need a larger hole.  So if I’m going to use them, I need to enlarge and re-dimple those holes now, before I put everything together and they become inaccessible.  I’ll almost certainly be using them, given the likelihood of fouling up solid rivets in those holes…glad I found this out now!

I’m starting to notice that as the empennage build goes on, the instructions are becoming less and less specific.  There’s a lot of hand-holding early on, but now there are extra little details that aren’t always spelled out, things that would be clear to a knowledgable builder.  My understanding is that this trend continues into the following kits, probably because the instructions would be a giant book otherwise.  So it seems as if the empennage instructions are gradually “teaching” me to figure things out myself and catch potential pitfalls before they become problems.  Nice.

I guess I’ll see you all back again on Tuesday, once my stuff from Spruce shows up.  I might even finish the rudder that night. (WHY DO I KEEP SAYING THESE THINGS?!?!?!)