Very productive day today. I picked up where I left off last night with the wing walk doubler. The basic procedure here is to lay the doubler in place under the skin, and then use the skin as a drill guide to drill all the holes to the ribs. I put a piece of my scrap MDF on the bench top to drill into, and used a drill stop to ensure I didn’t drill right through that MDF. The nice thing about clecos is that you can merrily cleco aluminum into the wood underneath it. In this case, I lined up the doubler and initially clamped it in place with cleco clamps. Then I drilled a couple of initial holes and used those to cleco the whole works to the MDF. That gave me alignment so I could remove the clamps and finish drilling the rest of the holes.

I totally meant to get a picture of the finished doubler, but I forgot and all I have is this photo of the skin clecoed down over the doubler:

From here, it was time to cleco all the top and bottom skins in place and match drill them. But first I wanted to see if I could rearrange the camp holding the inboard main spar to the wing stand. I did some tinkering around here, but never did come up with a good idea. I tried just clamping one side of the spar, but that kind of torqued the whole assembly and in general wasn’t going to be conducive to building a straight wing. I was getting a bit frustrated, just about resigned to having a clamp in the way for the foreseeable future, when suddenly an absurdly simple solution came to me. You see, the bolts that hold the horizontal pieces to the stands go all the way through the upright. All I had to do was switch the horizontals to the outboard side of the upright.

All that worrying and frustration, and I ended up solving it just by undoing and replacing four bolts. *sigh* Now I had plenty of room on the inboard end:

Better yet, this made it far easier to get the wing set up securely. Ever since I found out I made the bases too short, I’d always been looking at the stands with an attitude of “well, I can work around this.” That is, I knew it wasn’t right but I figured I could make do. Now, however, the setup is really and truly right. I can clamp the inboard end down securely, and instead of tweaking things manually to remove twist, I can use the adjustable horizontals and make a truly repeatable setup. Basically, this made me very happy, even if it did mean having to go through the whole routine of leveling the setup, checking for twist, taking the sag out of the spar, etc.

Finally, time to start clecoing the skins on. This isn’t an especially complex procedure – there are four skins, two top and two bottom, plus the wing walk doubler. The main deal is there are a lot – and I’ll repeat, a lot of holes. Even clecoing only every fourth hole or so, I used about 75% of my silver clecos, three coffee cans worth. (I think the coffee can is the official unit of measurement for clecos. You can count them, but that’s way too much work.)

I asked Josie to come out and grab some photos of me actually working on the wing, which is what you get to see now.

I had a helper come out for a bit too. Astute observers will note that I’m scratching his nose with one hand to distract him so I can place the cleco with the other:

And then I was done with the top skin, and there were two dogs, and there had to be a photo op:

OK, on to the bottom skin. But first, here’s a photo from the bottom. The shiny stuff on the left is the wing walk doubler. See, I told you I made it!

OK, now to really put on the bottom skins. Let’s start with the inboard one. Oh wait, something’s wrong here. Argh, the bottom inboard horizontal arm interferes with the skin! And here I thought I was done modifying these stands… (The skin is supposed to align with the rib visible to the left.)

After mulling over this for a bit, I decided to just replace that big piece of angle with a smaller piece from some scrap I had lying around. These pieces are just held in with self-tapping bolts, and they don’t go all the way through the upright. Oh, and they’re long enough to account for those 2×4 blocks. Rather than go run to Home Depot for shorter bolts, I made a little wooden spacer so I could reuse the bolt I had. Excuse me? Ghetto? The term is “redneck engineering,” thank you very much.

Anyway, where was I? Oh yes, clecoing skins. Back to that. Another half-hour or so, and the bottom skins were in place:

OK, time to bust out the drill and reamer and get to match drilling. I started with the top skins. The fun thing here is just how much things scale up from the tail kit. After feeling in danger of a hand cramp from the cleco pliers, I moved on to my right index finger getting tired from squeezing the drill trigger over and over and over and over again. And my arms were tired from holding the thing up. I can’t imagine trying to do this with, say, a heavy cordless drill (though the air hose presented annoyances of its own).

Eventually, the top was done, and it was getting on to about time for dinner. At first I was going to break for food and then match drill the bottom skins, but we decided to watch a movie instead, so that was the end of airplane work for Saturday. Tomorrow I can finish the match drilling, then move on to the leading edge and tank stuff. But at some point I should get to match drilling the right wing; that way I can take advantage of the next good weather weekend and get that thing primed and then riveted together.

Short day in the garage today. I had originally planned to go fly a bit today to stay current, but I fell victim to the notorious fuel-injected Lycoming hot start affliction. I couldn’t get the Arrow started to save my life, and after about five tries, it didn’t even want to turn over. I took mercy on the starter and gave up at that point. I then learned that they’ve been having hard start issues with the plane anyway, and it was going to get new mags installed that very afternoon. So I gave them an extra couple hours to work on that and saved myself a couple hundred bucks. On the way home, I stopped at Home Depot and bought some C-clamps and plumb bobs so I could finalize the left wing on its stand.

Back at home, after goofing off for a bit, I got to work. The first order of business was to finalize the clamping arrangement for the inboard main spar. I had just put some of my quick clamps on for a temporary fix, but now the C-clamps I bought would do the job. But first I needed something to pad between the clamps and the spar reinforcement bars; I don’t want to mar up those beautiful pieces of work. Some scrap wood from the H-stab moving fixture worked great, but only after I drilled some shallow holes to fit over the big shop heads on the spar.

Once I got to clamping, though, I realized things were going to be tight. The bases I made for the wing stands are barely long enough to fit the wings, a problem that annoys me greatly. You see, when I first sketched out those bases, I figured that the lengthwise pieces should be 120” long. This was especially convenient, since I could just buy 10’ 2x6s and not have to cut them. But then I reviewed my plans before I got to building, and somehow I convinced myself that 120” might be too long for the spars, and so I cut each piece down a couple inches. So basically, I second-guessed myself for no good reason and actually created more work out of it. *sigh*

Anyway, thanks to that little bit of stupidity, things are pretty tight on the inboard stand. The clamp kind of has to sit in this position, which is going to put it in the way when I’m skinning and so forth:

However, after reviewing the plans, I see that the fuel tanks sit a bit further outboard than the skins, so I think I may be able to flip this clamp and get some better working room. But I discovered that towards the end of the night, so I’ll wait until tomorrow to test that theory.

Next task was to put the plumb bobs on strings and hang one from the main spar on each end of the wing. Then I could measure the distance from the string to the rear spar and ensure that I had the same measurement at both ends, and in turn ensure I wouldn’t build any twist into the wing. I was actually a bit surprised by this, as I found about a 3/16” difference with the skeleton hanging naturally. So I did some adjustment of things before clamping the skeleton down fully, and now it’s nice and square.

Now, what to do from here? My original plan was to start working on the right wing skeleton; I could go ahead and cleco/match-drill the ribs, then deburr and try and get everything primed this weekend. But the weather has been spotty lately, with frequent afternoon storms and showers, and since I prime outside, that’s a bit of a problem. I decided instead to move forward with the left wing. The general path from here on out is to fit and match-drill the wing skins, fit the leading edges, and then move on to the joyous world of fuel tanks and Proseal.

First though, a wing walk doubler must be made. This goes under the main wing skin on the inboard part of the wing; this is where people will walk while getting in and out of the aircraft, so some extra structural strength is needed here. This is also one of those parts of the project where Van’s does not give you a nice prefab, prepunched piece; you get to cut these to size out of a larger sheet. And since the finished product is relatively large (9 3/8” x 26”), it’s too big for me to cut stuff on the bandsaw. Time to break out the snips

This led to an amusing farce during which I was looking at my three pairs of snips, trying to remember/figure out which was which: straight? left? right? ARGH. Well, straight was easy to figure out, and I’m making a straight cut, so I’ll just use those. It wasn’t so bad once I just got to work. After rough cutting with the snips, I attacked the edges with the vixen file to smooth them and shape to the final size, and then all the edges got cleaned up on the scotch brite wheel. The next step is to clamp this in place on the inboard wing skin and use the skin as a drill guide, but it was getting late by this point , so I knocked off for the night. As such, all I have right now is a rectangular piece of sheet. Holes will be forthcoming:

Side note: the little strip of aluminum I cut off with the snips curled up into an amusingly consistent spiral. It actually looks kind of cool. I should save these and sell them as modern art sculptures or something.

Short night tonight. We had a storm roll through and flood come streets while also disabling stoplights. As a result, my commute home was pretty ugly – instead of the normal ~20 minutes, it was over an hour. It honestly took so much out of me that I took a nap when I got home.

After that, though, I wanted to at least get the left wing on the stand. Josie helped me put it in place, and I set about getting it clamped in place. This ended up requiring me to modify the stands a bit – the pieces of angle to support the rear spar weren’t positioned quite right, so I had to do some customization. Nothing too serious though, and now the wing skeleton is securely in place. The only other thing I really need to do is get a couple of plumb bobs so I can ensure there’s no twist in the wing before I go to town match-drilling the skins and so forth.

Good news: Fixing that rib issue was pretty easy. I popped out to the garage after dinner and went to work. First order of business was to drill out the other two rivets holding the offending rib to the rear spar. That went fairly well, though it was a pain to drive the rivets out of their holes. I’m gradually learning that thicker materials = lots more grip strength for the rivet shaft = way more work to drive out. This is also another point in favor of putting the manufactured head on thinner material, because having to bang hard on a rivet to knock it out when it’s backed up by a thin rib is kind of scary. It’s really easy to bend the thin rib flange.

Anyway, with that rib freed, I unclecoed the other three wing walk ribs, and as I had hoped, I was able to pull the spar end out of the way enough for me to get in there and straighten the rib face. After that, it was straightforward to squeeze a new rivet; the hole seemed a touch oversize, but by pre squeezing the rivet a bit, I was able to get it set OK.

From there, I went to work on the rest of the wing walk ribs. These were straightforward too, until I got to the two inboard-most ribs. Here, there’s a lot of reinforcement material on the spar; there’s the long reinforcement fork that stretches outboard about 18”, plus another smaller reinforcement plate that only covers these two ribs. End result, there’s a lot of material thickness here. The plans call for -8 rivets here, but when I put one in and checked the length with my gauges, it seemed a little short. On the other hand, the -9 seemed a little long. I debated a bit and finally decided to just follow the plans.

Wrong choice. The shop head I made was way too thin. Time to drill out another one…I got the head off no problem, but tapping the rest out was a serious pain. Remember what I said about more material = more grip? This is where I really became convinced of that. I was really worried about bending the rib flange, so I ended up putting a couple of small C-clamps around the rivet to hold everything in place. It worked like a charm, but also scratched off some of my primer:

So I used the -9 rivets for those two inboard ribs, and that was the end of my rear spar riveting. Look Ma, no clecos!

FYI, the still-open holes in both of these pictures are for the flap brace and aileron gap seal, respectively. They get left open since those pieces won’t go on until much later.

I still had a bit of SEM primer left, so I went ahead and touched up the primer I’d messed up while taking care of that rivet:

And that settles the left skeleton! Tomorrow I’ll plan on moving this wing back to the stand and getting everything all straight and level for upcoming construction. Then I guess I’ll get to working on the right skeleton. I think things should end up being timed pretty well for me to clean and prime the right wing ribs this weekend, and maybe by next weekend I’ll have both skeletons on their stands. Then the real fun will start. (fuel tanks! Proseal! Oh my!)

Came home today to find a nice little present courtesy of Avery Tools. Longeron yoke, some long-reach 1/8” clecos, and a tube of Boelube for good measure. Finally, I can get back to this wing skeleton!

I got Josie to help me pull the skeleton off the stands and put it back on the workbench. Everything was still clecoed together, so it was just a matter of going to town on some rivets. Well, sort of…one consideration on this rear spar is that there are several different material thicknesses together, and thus several different rivet lengths to use. And there are also holes that need to be left open to accommodate the aileron gap seal and flap brace down the road.

I started on the outboard end; this is a particularly unusual spot in that it gets flush rivet instead of the typical universal head rivets. The reason for this is that the outboard aileron hinge bracket sits on top of this spot.

Outboard flush rivets:

The mocked-up aileron hinge bracket to illustrate why those flush heads are required:

From there I went on down the line and things progressed pretty quickly. The nice thing about squeezing rivets is that once you’ve got the squeezer adjusted for a particular rivet length and material thickness, you can breeze on down the line making nice consistent shop heads without the trial-and-error that comes with the rivet gun. Things went great until I got to the inboard end. It seems that I had a rib with a slightly bent flange, and I didn’t catch it before squeezing a rivet:

That’s a problem. I didn’t think much of it at first; after all, I’m to the point that drilling out rivets doesn’t stress me much. I drilled and popped the manufactured head off, then started tapping it with a punch, but it wasn’t moving. Then it occurred to me why: with that kind of a gap between the rib and spar, the rivet undoubtedly swelled up in the space between. I doubt it’d be possible to drive the rivet out without damaging the rib. So this is going to be a more involved repair than I originally thought.

The good news is that this is the fourth-most-inboard rib, and I haven’t squeezed any rivets in the other three ribs. My hope is that I can drill out the other two rivets in this bad rib and then be able to pull the rear spar out of the way enough to get this bad rivet out and straighten the rib flange. Worst case, I might have to drill out the five rivets in the main spar and remove the rib entirely. Hopefully I can avoid that, as the manufactured heads of those rivets are towards the inside of the skeleton, and drilling them out will be a chore…not to mention the concern of damaging the main spar in the process.

It was late by the time I realized the problem I had, so I decided this was a good time to call it a night. Much better to sleep on the problem instead of trying to attack it all willy-nilly. Tomorrow we’ll see if I can get this all fixed up.

Not much to report today. I recruited Josie to come out and help me rivet the ribs that I couldn’t do on my own. It was a bit odd at first (I may have some mild control-freak tendencies), but pretty soon we got into a good rhythm and before long everything was knocked out.

The dogs came out to hang with us as well; I figured it wouldn’t take much riveting to change their minds, but I was only half right. After about the second rivet, Mae retreated back into the kitchen, but Dood (yes, that’s his name) just kept lying on the floor without an apparent care in the world. So we decided to have mercy on his ears and put the Mutt Muffs we got for Mae on him.

I had originally planned to finish out the night by at least starting to squeeze the rear spar rivets, but after clecoing the spar in place, I discovered that I can’t squeeze them with the setup I have now. I have a long flush set for the squeezer that would allow me to get around the spar channel, but it’s too long to get it on the squeezer with the other set. I could shoot these as well, but access would be tougher than the main spar, and it’s a lot easier to get consistent results squeezing. So I’m going to order a longer on yoke this week and hold off on the rear spar rivets.

I figure tomorrow I’ll put the left wing on the stand and start match-drilling and generally prepping the right wing ribs. I might even be able to get all the way through cleaning and priming them tomorrow if I can actually get my butt in the garage early in the day. I need to get on building the other wing stand too…

Yes, that’s really all I did today. My work ethic hasn’t been so great, and a lot of the problem is me being a little insomniac. I stay up too late, then I’m tired the next day, I try to resist the afternoon nap urge, but inevitably I give in, and then at bedtime I’m not sleepy, and the cycle continues. We did get up at a decent hour today so we could take the dogs to the Houston Arboretum for a little walk through the woods. We wanted to go early in the morning before it got too hot, but seeing how this is Houston, it was still pretty hot for a 3/4 mile walk even at 10 AM. When we got home I was tired and sweaty, and then I realized that I needed to run to the grocery store. Long story short, I got that done along with some food prep and finally got out in the garage around 2.

Instead of jumping into riveting ribs today, I took a detour from the instructions. I’ve been reading over Jamie Painter’s build log from time to time, trying to get insight into upcoming tasks, and I ran across something useful while reading about building the tanks. It seems there are three nut plates on the inboard end of the spar, part of the tank attach system. This area of the spar is also where the wing walk will be; that is, the reinforced part of the wing that passengers will be stepping on. As such, the ribs are spaced much closer together. That means that if I wait until later to do these nutplates, I’ll have to work in a fairly confined space.

Here’s where the nutplates will live; each of those sets of one large and two small holes is a nutplate location.

There seems to be no reason why I can’t go ahead and install these nutplates now, while I can get the ribs out of the way and have good access back there. So I did it.

Actually, even with the ribs out of the way, it’s an interesting spot. The spar reinforcement plate doesn’t leave a lot of room to get a bucking bar in there. Squeezing is out of the question; the nutplates are too far away from an edge and the spar flange and forward reinforcement bars are too wide too. I ended up using my tungsten bucking bar here. Most everything went well, but on one rivet I let the bucking bar slip off, and the shop head ended up with a nice little step on it.

I considered leaving it in at first. Generally, a shop head like this is unacceptable, but for a nut plate, the rivet isn’t really taking any load; all it has to do is keep the nut plate from spinning. Once the bolt is installed, that will be the main load path. Still, I was bothered by the bad rivet, so I decided to drill it out. I got the head off OK, but realized I needed a second set of hands to back the nutplate while I punched out the rivet, lest I ruin the nutplate and then have to drill out the other rivet as well. And here Josie had just run out for a few errands. So I went back inside to take a break…which of course turned into the nap I’d sworn I wouldn’t take today.

Finally, I got back out later and had Josie help me punch out the rivet. It turned out it was a useless wait anyway; the nutplate was still bent and I still had to drill out the other rivet and replace it. Then it was back inside to call and talk to my parents before it got too late over in the Eastern time zone.

This is the nutplate I replaced. I still put an ugly shop head on the lower left rivet, smeared it a bit, but drilling it out will probably cause more damage than good, and as I mentioned before, it’s not as critical here to have perfect rivets. You can also get a better idea of how the spar reinforcement (the outer raised area) gets in the way.

And things are just as fun on the forward side. Notice the spar reinforcement bar below these rivets, covered in blue tape to prevent marring. I could barely get the rivet gun with the flush set into the outermost rivets.

While I’m still annoyed by these short weekend work days, it’s still better than not working at all, I suppose…

I started out my day by heading up to Weiser Air Park for the monthly lunch the local RV builders do. I hadn’t been to one in a few months due to other commitments, so it was nice to go hang out, talk about building, and most importantly drool other everyone else’s airplanes. One the guys who flew in today was in this sweet-looking RV-8. My practical side is a little unsure about painting an airplane in anything vaguely low-visibility, but I have to admit that this is a cool paint job.

After watching everyone depart – a process that culminated with a low high-speed pass from an RV-10 driver – I headed home, feeling motivated to get to work. That got a little sidetracked when I decided to lie down for a few minutes, whereupon staying up late Friday night caught up with me.

Finally, rejuvenated, I went out to the garage. Mindful of how long it’d been since I shot rivets, I did some practice runs with a few scrap pieces before going to work on the spar itself. I was still kind of nervous for the first few rivets, but before long I was getting into a good groove. And that, of course, is when things got interesting. I was on the inboard end of the wing, where the spar reinforcement bars make the top and bottom rivets slightly more difficult to see the shop head side. I had shot four of the five rivets on this rib just fine, and the last one was the topmost. I inserted the rivet, got the gun and bucking bar in place, squeezed the trigger for a bit, then bent down to check my progress.

I was shocked to see a tiny shop head. Wait, did I not get the rivet in all the way? I checked the other side – nope, the manufactured head is flush against the rib flange. What happened?

I was confused by this for longer than I’d like to admit, until the obvious occurred to me – somehow a shorter rivet must have gotten mixed in with the ones I was using. If I’d been in any other hole, I would have seen this before shooting, but it just so happened to be the hole where my vision was obstructed.

Well, time to get drilling. This turned out to be a pain; I got the manufactured head popped off pretty easily, and started trying to punch the rest of the rivet out, but that thing was in the hole quite securely. My level of violence wight he hammer continued to rise before I realized that this was exactly the mindset that caused things to get damaged. It was getting on towards dinner time anyway, so I left things alone, fired up the grill, and cooked off some brats. We ended up watching a movie with dinner, after which I went out and, with my mind calmed down some, got the rivet punched out (though not after drilling all the way through it and using pliers to help encourage it). The hole seemed good but maybe slightly oversized; not enough to need to drill out to the next larger size, but enough that I was worried about the shop head clinching (this tends to happen when there’s extra play in the hole).

Fortunately, there’s a well-known solution to this. I’d never tried it, but you can take a rivet squeezer and give the rivet a tiny bit of squeeze, just enough to swell the shaft and snug things up. It worked like a charm; I shot the rivet and then called it a night.

Tomorrow will be more fun. All the ribs I did today had their flanges facing left, which made it easy for me to shoot and buck. Some of the ribs, though, face the other direction. The only way I’d be able to shoot and buck those would be to switch hands and shoot left-handed. I’m not too confident with that ability, so I’ll probably get Josie tome come out and help.

Not much to see here. I got a somewhat earlier start today because I worked from home for the second half of the day. It sure helps to not have to sit in evening traffic to get home…

Anyway, straightforward stuff today. I started out by finding the outboard-most rib and bolting on the piece of angle that’s used to attach the skeleton to the stands, then I clecoed that rib in place before setting the spar onto the stand. From there, it was a fun game of putting each rib where it went. I guess my binary system worked OK, because I got everything right the first time, without any oddness. Then I took the whole assembly back off the stands and laid it on the workbench to cleco the rear spar on. This seemed preferable to sitting on the floor and trying to line things up and cleco at the same time.

Hey, that looks like part of an airplane:

From there, I grabbed a couple of wing skins and did another one of those “because I can” assemblies:

Then it was time for dinner and we decided to watch a movie afterwards. Maybe tomorrow I can bang some rivets? I’m a little skittish; it’s been over a year since I shot rivets with the gun, and that’s going to be a necessity here. Even better, I’ll almost surely have to use the offset set to get in some of these places. I guess I should probably get some practice in before I go to town on the wings…