Again, not much to report. Josie wasn’t feeling well again, so I came up with a plan to shoot the last few LE rivets myself. I’ve been shooting these rivets with the LE in the cradle, which means that the holes toward the edge are facing somewhat downward, which in turn means that the rivets want to fall out. So I set the LE on the workbench facing up, put all the rivets in place, and secured them with rivet tape, like I was going to back rivet. From there, I was able to use my usual technique to shoot the rivets – it actually turned out to be far easier than I’d expected.

Before setting the LE units in place on the spars, I took a moment to check the hole depths of all the LE-spar rivet holes. As I mentioned a while back, I’m going to use Cherry blind rivets in all these holes instead of trying to shoot solid rivets with really limited access. I already have the rivets I need, but I wanted to double-check the material thicknesses against the grip length of the rivets I had. For obvious reasons, I don’t want to use inappropriate rivets here…

That done, I set the LE units in place and went to work clecoing them, both through the spar to the ribs and through the skin to the spar flange. And of course, just as I was finishing this, I found a problem:

That’s the tiedown ring mount on the right wing, and somehow the skin hole is misaligned. I could swear I test-fit the tiedown ring in both of these holes, but with this alignment, I couldn’t get the ring started. Urrrgh. So I got out the Dremel with a cutting bit and carefully enlarged the hole, doing my best to try and keep it round. And there was no good way to deburr it effectively in place, so I went and removed all those stinking clecos I’d just put in, just so I could pull the unit off and spend 30 seconds deburring the hole.

The end result isn’t perfectly round, which kind of bugs me, but it’ll do. I doubt many people will ever notice this really:

I’d hoped to pull a few of the Cherry rivets tonight, but after fixing the tiedown hole, it was after 11 and so I decided to quit. As a final note, here’s the right LE unit all clecoed in place:

Finishing the LE riveting didn’t happen tonight. Josie ended up working late and didn’t feel well after that, so we’ll wait for another night. In the interests of achieving something, I ran out and primed the corners of the main skins where I filed the scarf joints.

Update: OK, that wasn’t all for the day. I remembered that I neglected to note/remember that one rivet hole I countersunk and enlarged a while back. Turns out it was one of the holes I riveted solo over the weekend, so I went ahead and drilled out the original rivet, enlarged the hole, and installed a NAS1097 rivet in its place. Along the way, I noticed a few underdriven rivets, so I hit those up a bit more with the gun.

I started out today by dimpling all the main ribs and both rear spars. The instructions say you should touch up the spar dimples with a countersink for a better skin fit, but when I did a test fit with a dimpled skin patch, I had really good fit with just the plain dimples. The instructions also warn against taking off too much material in this step, so I decided that not countersinking at all was the best choice.

Then it was time for some riveting. First I squeezed a few rivets on the spar; the main ribs that sit behind the fuel tank each have a hole on the top and bottom where there’s a rivet just through the spar and rib, which will then sit under the tank skin. Those were easy to squeeze, then I moved on to the big job – the LE units. I was mindful of the incident where I dropped a bucking bar and put a dent in my tank skins, so this time I put some old towels and rags down in the bottom of each bay just in case:

Then it was lots and lots of shooting. I got all the rivets except for the forward most three on the top of each unit – I’m going to need help for those, and since Josie was working most of the day today, I couldn’t recruit her. We should be able to get those rivets done one night this week, I think. In the meantime, I set the almost-finished LE units on the spars for a photo op:

The afternoon was still young at that point, so I decided to go ahead and start dimpling the main top wing skins and the wing walk doublers. That took quite a bit of time, but I got all the skins done, at the cost of a couple blisters. Yep, there are lots of rivet holes in these wings. But hey, dimpled skins!

At this point, I figure my evening tasks for this week will be finishing the LE skin riveting, riveting the LE units to the spars, and priming the corners of the main wing skins where I made the scarf joints earlier. Then next weekend can be main skin riveting time!

Got in some more tailwheel time this morning, came him for a nap, and didn’t get a whole ton done as a result. I basically spent all three hours countersinking all the rivet holes in the main spar. I had to take frequent breaks to rest my arm and let the drill cool off – gets a little hot when run more or less continuously…

Along the way, I noticed a small gouge in the bottom of the left main spar. Not really sure where it came from, but it was deep enough to catch my fingernail, so I got out the dremel to smooth it out before sanding and priming the area:

Tomorrow I should be able to get more done. I’d like to get all the ribs dimpled and then get started riveting the leading edge units together. By this time next weekend I might be riveting the main skins!

Not much to see tonight, basically just an instant reply of Tuesday. I pulled the top skins and tank off the right skeleton and went to work deburring all the skin rivet holes. Then I did a little shop cleanup afterwards; I have a pretty bad habit of leaving tools sitting out when I stop work for the day, and Tuesday was no exception.

Afterwards, I got curious about just how many rivet holes I was deburring, so I went out and did a quick count. It’s not that hard since you can count the holes in each rib and multiple by 14, and also take advantage of some symmetry in the spars. Anyway, the final number I cam up with was just under 1250 – for each wing! I wasn’t expecting a number quite that high…

I’d like to summarize this evening’s work with a simple statement: There are a lot of holes in the wing skeleton. I know this because I deburred every last one on the left wing, and yes, it really did take two and a half hours. And that’s still not all the prep tasks, I also have to dimple most of those holes and countersink the rest – that’s probably another good night’s work, though in practice my plan is to deburr the right skeleton and then try to do all the deburring and countersinking on the same day.

No photos tonight, but if you want to exercise your imagination, you can try to picture me lying on the garage floor so I could get to some of the holes on the rear spar. I’m sure it was an entertaining spectacle.

Between sleeping in today and having some non-airplane things to do around the house, I didn’t get in quite as productive a day as yesterday. But hey, I still got some work done. First main goal of the day was to continue prep work on the top main wing skins. With the rivet holes deburred, today I went to work on the edges, first giving them a good filing to get rid of some raised areas, then hitting them up with a scotchbrite wheel in the die grinder to make everything nice and smooth.

Along with this garden-variety edge finishing, there was also some special work to be done on these skins. Since there are two skins per wing, there’s an overlap where they join, which in turn means the outboard skin (which sits on top of the inboard) sticks up behind the tank skin. Here’s a blurry photo of that seam without any work done:

Sorry the photo’s bad. It was rather difficult to get that shot at all, but you can see the outboard skin on the left side (background) sticking up above the tank skin (foreground). The solution to this problem is to carefully file that corner of both skins into a nice taper, a sort of scarf joint type setup. To start this, I measured points 3” out and 4” back from the corner, marked them, then laid out a few layers of masking tape to protect the area I didn’t want to taper:

Then I went to work with a vixen file, followed by a regular file, followed by emery clutch, followed by a green scotchbrite pad. My goal was to get the tip of the corner down to about 2/3 the full thickness, or about .016-0.18. After tapering the corner of both skins, the joint turned out very nicely:

After tapering the second set of skins as well, I moved on to a few minor items. I riveted the nutplates onto the replacement joint plate I primed yesterday, then clecoed the joint plate and the last rib into the right LE unit. I also went ahead and riveted the access hole filler panel to the doubler, but stopped short of riveting it to the LE skin itself. I got a little distracted while doing this and rather stupidly riveted one of the holes in the doubler itself. Whoops:

At least those rivets are easy to drill out. Here’s the plate/doubler assembly clecoed to the left LE skin:

I wish I hadn’t scuffed the outside of that panel. I had intended to prime the inside of it, but I got carried away while cleaning and scuffed both sides. Oh well, no harm done, just looks rough.

Anyway, that does it for all the LE parts. Nothing left to do with these things but to start riveting! Guess I better get started…

PS I forgot to mention it, but yesterday I crossed the mark of 500 hours spent building this thing. The Van’s estimate for time to build is 1500 hours, though consensus seems to be that number is optimistic. I figure 2000 is likely the upper end of the potential range for me, so I guess I’m somewhere between 25 and 33% done with this project! (I can’t decide if that number is exciting or sobering)

Nice productive day today. I was supposed to fly this morning, but for the second weekend in a row the weather forced a cancellation. But hey, more time to work on the plane. Despite it raining all night and there being a persistent overcast in the morning, I knew it was going to clear up later, so I went ahead and cleaned the few parts I had so they’d be ready to prime. Of course, they took forever to dry in the cool humid air outside.

Meanwhile, since the first landing light lens work was still fresh on my mind, I decided to go ahead and do the other one. I clecoed together the right LE, sans the inboard rib and joint strip, since they were on the priming list for today. They’re at the other end of the unit from the landing light, so they won’t affect the fit of the lens. As is usual with things like this, my second lens came together quicker and was better quality than the first:

By this time, it had cleared up outside and the cleaned parts were dry, so I got started priming them, and in between spraying coats, I did some tidying up in the garage. The floor was getting kind of nasty, especially under my main workbench, which hasn’t moved in probably six months or so. The composite of spider webs, dog hair, and metal shavings down there was quite impressive.

So now what? Spar countersinking will still have to wait until next weekend or after whenever my in-out deburr tool comes in. I could go ahead and start riveting the LE units, but I wasn’t in a riveting mood (whatever that means). Instead, in keeping with the instructions, I decided to turn my attention to the top wing skins. They need to come off anyway so I can deburr and dimple the main ribs and the rear spar, and of course the skins need to be deburred and dimples as well.

It’s been a while since I had bare skeletons sitting out here:

Now for the real fun…removing the blue vinyl. I need up with a vinyl pile the size of a small child:

And then I went to work on the rivet holes. Sorry, no exciting pictures here…just me doing lots of menial work. I got all the holes in the top skins done and quit for the night at that point. Tomorrow I suppose I’ll take care of the skin edges, get them dimpled, and probably dimple the main ribs and rear spar as well. And then I guess I really will have to get into a riveting mood and go to work on the leading edge units.

I’m finally reaching one of those building stages where things start coming together quickly. Once the LE units are riveted together, they’ll get riveted to the spar. Then the top skins get riveted. And then the wings come off the construction stands and I start working on control surfaces. My fuselage kit is expected to ship the second week of February, so I should have no trouble having the stands out of the way before the fuse gets here, though I might still be working on the flaps and ailerons.

I’d really hoped to be able to prime the couple of leftover pieces I have today, but unfortunately it rained all day. So much for that plan, maybe this weekend. Instead I decided to start today off by dimpling both LE skins. First, though, I needed to make some modifications to my dimpling fixture. I found when dimpling the tank skins that the C-frame tended to wander downward in the fixture, since the fixture has no bottom. So when we dimpled the tanks, we had to stop every ten holes or so and realign the C-frame with the fixture. Kind of annoying. 

I had a piece of plywood big enough to cover the entire bottom, but that would require me to cut it to size, which would require working outside, and yeah, there was that whole rain thing. So instead I decided to use some leftover 1×6 lumber to make little shelves under the C-frame slots. I also put a piece of 1×6 at each outside corner so the thing would sit flat:

Much better:

A few hours and a lot of pounding later, I had two fully dimpled skins. Look, dimples!

Now what? It was only mid afternoon and I didn’t feel like quitting that early. At first I was going to see about countersinking the rivet holes in the main spars, but then I realized I needed to deburr those holes. Rather than do that tediously with the hand deburring tool, I think I’m going to get an in-and-out deburring bit. That should make deburring spots like this much easier, and I expect the tool will get lots of use.

Instead, I went ahead and clecoed the left LE unit together and proceeded to work on the landing light mount. The next logical step was to fit the lens. First, the prevent lens piece gets trimmed down to size; it won’t fit through the LE hole without trimming. At first I tried trimming the plexi by scoring and breaking it, but that turned into a horrible mess. So instead I used the bandsaw, which made great cuts but covered everything in a 20-mile radius in fine sticky plexiglass dust.

Rough cut:

Once the cuts were done and the edges sanded smooth, it was time to fit the lens in place and drill the mount holes in assembly with the LE skin. I followed the Duckworks-recommended method of using tape to pull the lens in place while drilling, and it worked rather nicely:

After drilling the lens holes to full size and countersinking them for the skin dimples, I went to work installing the nutplates on the mount strips:

Those strips get stuck to the inside of the lens with double-sided tape. Oddly enough, the Duckworks kit includes two pieces of the tape, but neither piece is the length of the mounting strip. So I cut each strip into three pieces and put each piece of tape right under a screw hole. Seems logical since that’s where the screws will be pulling everything together.

Finally, I screwed the lens into the LE skin to check the fit. Looking good!

Fitting that lens took a startling amount of time, but since it was my first time working with plexiglass, there was a fair amount of trial and error. Fitting the second lens should go much faster; if I can get stuff primed this weekend, I should be able to assemble the right LE and fit the lens maybe Sunday, and then I can start riveting the LEs. Then it’ll be on to riveting the top main skins to the wings…but there’s lots more deburring and dimpling to be done between now and then.

Kind of a catch-all day, moving towards the point where I start riveting the LE units. At this point the main task remaining is to dimple the skins, along with priming the replacement joint plate and the access cover/doubler I made yesterday.

First task today was to finish up that access cover. Not much to see here; I just laid out the rivet lines, drilled the holes in the cover, and then used the cover as a template to drill the holes in the doubler. I went ahead and deburred and dimpled all the rivet holes while I was at it.

Next, I addressed another issue caused my my decision to skip the stall warning kit. There are prepunched holes in the left LE skin where the stall vane would mount, plus two holes right on the leading edge that serve as guides for the slot for the vane. These needed to be filled somehow:

There seem to be several approaches to this, mainly either using body filler, or filling the holes with rivets. I opted for the latter, going with NAS1097 small-countersink rivets. So I reamed the holes out to #40, deburred, and then put a slight countersink on the skin side. I intentionally made the countersinks a little shallow so the rivets would sit slightly proud. Once I’d set the rivets, I carefully filed and sanded them down until they blended nicely with the skin. They’re still noticeable on bare metal, but should be all but invisible once the airplane is painted:

With that done, I set about deburring both LE skins. This constituted most of the time I spent today; hitting every rivet hole with a hole deburring tool, then going to town on the skin edges with the die grinder.

After that, I decided to look at the directions – which I haven’t don’t in quite some time. They mentioned installing a pitot tube fitting before building the LE units; I’m using an aftermarket pitot that will mount differently, but I figured I should take a look at it anyway. I verified that it won’t interfere with the LE installation, but after reading through the directions and looking at the mount, the backing and washer plates needed a touch of filing to fit around the mast. Apparently Gretz intentionally cuts these plates a little small, since the batches of mast tubing vary slightly. This allows the builder to fine-tune the fit, which is exactly what I did – a touch of filing, and now everything fits together nicely:

I guess I’ll see if I can get the skins dimpled this week, and maybe next weekend it’ll be time to rivet. Though I just remembered (as I was typing) that I’ll need to countersink the main spar flanged to accept all the wing skin dimples. Maybe that can be an evening task one day this week; should be pretty straightforward, just time-consuming. (lots and lots of holes…)