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…)

Today’s main goal was to have a go at making a replacement for the W-423 joint plate that I found out was fouled up. This turned out to actually be easier than I thought, though it still took a fair amount of time since I was being careful about the fitment. I started by hacking off a section of my scrap LE skin; I figured there was a decent chance it’d take more than one try to get this joint plate done right, so I gave myself lots of extra material:

Next I trimmed off the prepunched edge using the band saw. Which, by the way, was lots of fun – feeding this fairly large bit of metal carefully through it. The bent area was especially enjoyable. Next I set the bandsaw fence to the right width for the joint plate strip, plus an extra sixteenth or so for good measure. Any extra width will just sit inside the LE bay and not get in the way of anything, so better to make this too wide than too narrow:

Now for the tedious part. I started by using the right tank as a template to drill the nutplate holes. The challenge here is that the tank is dimpled, and I was worried about the dimples causing inaccuracy. I mitigated this by doing one hole at a time down each side of the strip; I’d clamp the strip in place, center punch the next hole, drill that hole to size, deburr and dimple, then clamp everything back together again. I worked my way down the tank like this, and in the end things lined up pretty nicely:

The next step was to drill the joint plate to the right LE skin. I put the tank on the spar and ran in a few of the screws on the top and bottom to hold it to the spar. Then I assembled the right LE unit, sans the inboard rib. This allowed me to use the LE skin as a drill template for the joint plate. Here again, I worked my way gradually down each side, clecoing as I went to ensure everything stay together nice and tight:

That’s all well and good, but next came the real test: would that inboard rib fit inside the joint plate strip? I figured it was possible that it distorted enough during fitting to the tank that it might have been too small. But I was able to get the strip clecoed to the rib, though it took some coercion. I ended up taking the nose of the rib to the scotchbrite wheel just to remove a little material and facilitate a better fit:

Finally, it was time to put everything together and do a full-up fit test. The rib and joint plate were clecoed into the LE unit:

And then I put the LE and tank onto the spar. Fits great, and the tank and LE line up really nicely:

Whew! It’s a relief to have mitigated that problem.

I wasn’t quite ready to call it a night at that point, so I decide to set about making a doubler and access plate for the left LE skin. There’s an access hole precut in the skin to allow for access to the factory stall warning system. But I’m not going to install that, since I intend to install a real AoA system instead. As such, I’m going to permanently seal up this access hole; I could do that using the parts provided with the stall warning kit, but I intend to sell that kit as a unit, and the buyer would probably appreciate having the doubler and access plate included. Besides, the prepunched holes in the access plate are for screws; by making my own plate, I can drill for flush rivets instead.

First up was the doubler. I just traced the outline of the provided doubler, rough cut with snips, and then refined the edge in the band saw. The edges were cleaned up with the scotchbrite wheel, and then I used the LE skin as a template to drill the rivet holes. I decided not to cut out the center; it would just be extra work for not much reason (other than saving a tiny amount of weight):

Next was the cover itself. This took substantially more time as I fine-tuned it to fit the hole. I started by using the LE hole to trace the outline, then cut to almost-there size with the band saw. The straight edges were refined right down to the marker lines with a vixen file, and then I used a cutting bit in the Dremel to round the corners. From there, it was a long and repetitive process of carefully filing down the edges and refining the corners with emery cloth until I finally had a nice snug fit:

And that really is enough for one day. Tomorrow I suppose I’ll lay out and drill the rivet holes between the access cover and the doubler. Hopefully I can also get to deburring and dimpling both LE skins. It’d be nice if I could clean and prime the new joint plate and that access cover doubler, but tomorrow is going to be rainy. Maybe Thursday will be nice, we’ll see…

Well, so much for having a big productive day – though I kind of knew today wouldn’t go so great since I had a flight scheduled in the middle of it. I went out into the garage today thinking forward to getting some mundane tasks out of the way, figuring that it wouldn’t be long before I could start riveting the LE units together.

First task was to rivet the nutplates onto the W-423 joint plate, which joins the LE unit to the fuel tank. It didn’t take long before I realized that there were some real problems here. The nutplates didn’t seem to want to line up right with a cleco in one side, so after futzing around a bit I ended up putting a screw in each one to hold it in place. That’s when it became clear that the nutplate rivet holes weren’t drilled correctly. This was the plate that I started out wrong, by trying to cleco the nutplates in place before dimpling the screw holes. I thought things had turned out OK, but apparently not. I guess there was just enough slop in the clecos before to fool me.

Bad rivet hole! No donut!

So long story short, it looks like I’m going to be replacing this part. It’s going to be a bit challenging, since this plate has to align with three other parts (the LE skin, the tank skin, and the inboard LE rib). I think I have a pretty good idea how to make everything fit together, but it’s going to be a bit tedious. On the other hand, I have abundant material around to fab up a replacement, thanks to my ruined skins. Even better, I think I’ll make the replacement out of the ruined LE skin, so it’ll have the correct bend in it right off the bat. That might help some with getting everything aligned correctly.

Anyway, that ate a lot of time this morning: figuring out I had a problem, sulking about it for a while, searching around on VAF to see if anyone else had had a similar problem, all that fun stuff. Before long it was time to get ready for my flight – which ended up not happening due to some gusty winds. Probably a good idea, since I had trouble last week with relatively minor crosswinds…should probably tame the taildragger in those conditions before I go out when it’s really blowing.

Finally, in the afternoon, I was in a mood to go work again. I started with the other joint plate, and was relieved to find that I didn’t have the same alignment issues there. The nutplates went on without much trouble, and once I had them all riveted, I got out the left tank and screwed the joint plate in place to verify fitment:

Next I turned my attention to the outboard rib pairs for both LE units; the landing light reflector mount will go between these ribs, and those nutplates needed to be riveted in as well. Fairly straightforward work really. Once I had one pair done, I got out a reflector and screwed it in place between two ribs to illustrate how the light mount will look:

And that was it of the day. I set about putting together some dinner, and then we sat down to watch a movie. I guess tomorrow I’ll set about trying to make the replacement joint plate. We’ll see how that goes…

Forgot to write this up last night, but I got out of work early, what with it being Christmas Eve and all. That meant I was actually home before dark, so I went ahead and finished priming the leading edge ribs before coming in for dinner and a movie and such. Time to start putting stuff together. Might even get to riveting this weekend since I have three days in a row…

Yup, it’s priming time again! With the LE ribs prepped, it was finally time for the joy of scrubbing and priming. Before I got started priming, I decided to try to work out a better way to hold the ribs while I primed them. Most of the time I’ve just been setting parts on on sheet of plywood on saw horses, but it’s tough to get good coverage this way, and things become even more annoying as the spray can gets empty and it won’t pray if not held straight up. When I did the main wing ribs, I rigged up a whole system of little hooks on a string in the backyard, but that had its own annoyances. Even with the ribs secured at the top and bottom, they would twist in the wind, which made things annoying in its own way.

So today I started to think of maybe using the plywood, but at an angle. That would probably hold the ribs steady, but mostly vertical. But how to do it? Nails would be annoying. I hunted around the garage waiting for something to jump out at me, and finally it happened. I had some little twists of aluminum from trimming something a while back, and I cut them into short lengths that I then bent into little s-hooks:

These fit nicely on the 1/4” plywood sheet I use, and as a bonus, they’re not permanently attached and so I have some flexibility for how I use these things. I suspect they’ll continue to be handy. But now I had another little issue: I tried leaning the plywood against a sawhorse, but that put the lower part of the ribs pretty close to the ground, which would probably be an issue for ease of spraying. Maybe I could somehow mount it up higher on the sawhorse…back in the garage to look for something I could use. Aha! I still had the length of 14” tubing that was intended for the fuel pickups, but I didn’t use it. I cut it in half and made two little hooks that hung on the sawhorse, and finally I was in business.

Here’s the final product:

About the only issue is that I can’t easily spray the outside of the flanges, but I found I could easily just hold each rib after I’d sprayed everything else and get those flanges.

The only problem I ran into was…I ran out of primer while spraying the inside of the second batch of ribs. So that kind of put an end to work for the evening. I’ll have to see if I can get to a NAPA tomorrow and get some more 7220 primer, and maybe finish shooting those ribs after work tomorrow.

So my main goal for this week is to be at a point where I can prime the LE components this weekend, and I’m pretty much there. Tonight I started by working on the left tank attach strip. First I reamed the screw holes out to final size, then pulled the strip and dimpled the screw holes. Finally, I clecoed the nutplates on, drilled their rivet holes, and countersunk the holes for the NAS1097 attach rivets.

The attach strip with nutplates clecoed in place:

Next was a good old-fashioned deburring session, featuring the attach strip and all the ribs. Then I went back, dimpled all those parts, and peeled off the part ID stickers. And just like that, I have a big stack of ribs waiting for primer:

The only other part I really need to worry about is the doubler for the stall vane access plate. Since I’m not going to install the stall vane, my intention is to permanently rivet that access plate in place, but I’ll still need the doubler to get that done.

In other news, I’ve placed orders for my fuselage kit and for a set of Grove airfoil gear legs. I won’t be needing the legs any time soon, but Grove only does production runs a couple times a year, so I wanted to go ahead and get my name on the list. Turns out they’re just about to start a run of legs, so I should have mine in March…which won’t be too far behind when the fuse kit shows up. It might get interesting figuring out where to store all this stuff…

Yes! I am still building an airplane. Kind of surprising how being out of town for a week got me out of the working mood. Last weekend might have been a good time to get going again, but instead I was attending an EAA SportAir workshop on electrical wiring and avionics and such. Just like the sheet metal workshop I did prior to starting my tail kit, it was an incredible learning experience. Yesterday, I had my third tailwheel training flight with Joy at Texas Taildraggers (HIGHLY recommended, by the way), followed by the FlightAware Christmas party in the evening.

Truth be told, I came close to spending today bumming around the house too, but around mid afternoon the weather was so great that it seemed a waste to not finish prepping the right leading edge ribs and get them primed. Of course, as soon as I got started working in the garage, a nice rain shower rolled over and it stayed cloudy the rest of the afternoon, so I didn’t prime after all. My new plan is to get the left leading edge parts prepped this week so I can prime everything next weekend.

Anyway, down to details. Last time out, I’d deburred the right LE ribs and such, so all that was really left before they were ready for priming was to dimple/countersink the rivet holes as needed. I ended up running into some problems here; way back when I drilled the rivet holes in the inboard LE ribs, I felt they were a little closer to the rib web than I’d like, but I figured they were fine. Turns out they were close enough to make dimpling a bit difficult due to the size of the dimple dies. I managed to get all the holes done OK, save for one at the nose of the rib. There was no way to get the regular die in there, and none of my other special dimpling tools fit either.

So on the spur of the moment, I decided to countersink the hole instead. Bad idea; I neglected to consider the thickness of the material, and the resulting countersink went all the way through the material and enlarged the hole. Stupid. At first I considered fabricating a small doubler plate to go inside, but that would still leave a bit of a void in the hole. Finally, I realized this was a great place to use a NAS1097 oversize rivet; the enlarged hole was still smaller than #30, so this is a perfect solution. I’ll just enlarge this hole and the other two holes to #30 and things will be fine.

Here’s the enlarged hole with a rivet to show how oversize it is:

With the right LE parts ready for priming, I went to work on the left LE. I pulled the two outboard rivets and drilled the nutplate holes for the landing light reflector mount. About that time, dinner was ready, so I went in to eat, and after that, I got to doing some research for my fuselage kit order, which I intend to send in tomorrow. I think I’ve decided on the items I’ll add/delete from the kit – I’m going to do rear seat rudder pedals, mainly because the formation clinics I’ve seen require them, and I do want to do form down the road. I’m also doing electric aileron trim, and I’ll be chucking the heavy stock steel gear legs in favor of lightweight Grove units; in fact, I’ll probably end up ordering the super-slick airfoil legs.

Ordering the fuse kit really starts the clock ticking; I’ll need to have the wings off the stands before that kit arrives, or I’ll have nowhere to put it. But I don’t think that’s a huge challenge to be honest; I only need to get as far as riveting the top skins before they can go into storage. My plan is to leave the bottom skins off for the time being to facilitate installing an autopilot servo and any other internal stuff I may end up needing as time goes on.