Kind of a token night of work this time. I considered taking the night off, but I like the feeling of momentum I have on the project right now, so I figured I’d at least do a little bit.

What I wanted to work on was squeezing the rivets between the trailing edge of the top skins and the rear spar. Initially I tried squeezing those with the wings in the cradle, but that was rather challenging. So I got Josie to come out and help me move the right wing to the workbench:

After a fair amount of squeezing, I had almost all the trailing edge rivets done:

The remaining rivets are on the inboard end, where the spar channel is reinforced by a doubler. Access there is going to be tight, so I’m going to do those another night. I might actually have to shoots those, especially the lat few inboard ones, where there are two doublers. There’s just precious little space to work here, and I don’t think even the thin-nose squeezer yoke will work here: (also, I need to clean my camera lens)

As planned, I went in and left work early today. Got home not too long after 5, changed, and went right to work on the wing cart. The tough part of this is that, since I was recycling the bases for the wing stands into the cart, once I started, I was committed to finishing this thing, unless I could find somewhere to lay the wings overnight.

First I unbolted/unclamped the wings from the stands, then got Josie to come out and help me carry them out of the garage. We just set them out in the grass while I worked:

Then there was a lot of unscrewing and unbolting to take the stands off the bases and get the bases apart. I managed to get it done before it got dark, and so I was able to cut the long 2x6s to final length in daylight instead of having to set up a work light or something. Then I assembled the lower channel of the cart; this was a modification of the “normal” cart design I made. Instead of having a single plank serve as the cart’s “backbone,” I used two 2x6s, with a 2×4 in between. The result was a U-shaped channel at the bottom of the cart. I also added two more 2x6s at the top running lengthwise. This creates a nice little pocket between the wings where I can store the bottom wing skins, and thusly solves a logistical and organizational problem.

I was going to add some diagonal braces for stability, but with just the channel and two more 2x6s, this thing is pretty much rock-solid:

With the bottom wing skins stored in the middle:

Then I rolled the beast out into the driveway and we loaded the wings into it. Perfect fit!

I quit at this point; it was almost 9 and I hadn’t even had dinner. I still need to clean up the garage from all this work and get things rearranged at some point. My next task on the wings will be squeezing all those remaining skin rivets, and then I can fit the flap brace and aileron gap fairing to each wing. I might be able to get the control surfaces done before the fuse kit arrives in a couple weeks; if not, it won’t be a huge deal.

Tonight I just went out, inspected the rivets we shot last night, and marked the few that needed to be shot a little more. All told it was maybe 20 or so, not bad at all. It would have been a short work session, except that last night Josie also pointed out that the rivets through the leading edge skin and into the spar looked like their shop heads were undersize. Sure enough, I checked and they were. Guess I was a little overeager that night. I got out the squeezer and easily fixed all of the rivets on the bottom, but the tops ones were now inaccessible since the top skins were on. So after fixing the few bad rivets from last night, we went down the line on both wings and hit up all those LE rivets again.

So tomorrow I’m going to go in to work early so I can head out early and shoot for getting the wings off the stands and the storage cart built. I did run into a slight hiccup tonight – I bought some adhesive foam weatherstripping to pad the end of the cart where the leading edge will sit in it, but when I tried a test-fit with the wings, the weatherstripping gripped the LE skin and pulled right off the wood face. So that’s not going to work like I’d hoped. I may need to get a different material or something, I dunno. Or I could cut narrow strips of the carpet I have lying around and attach it with carpet tape, but that’ll be tedious.

Update: I went out and played with the cart stuff again. This time I stuck the weatherstripping in place with carpet tape instead of relying on the rather weal weatherstripping adhesive. I also left the paper backing on the non-adhesive side of the weatherstripping to promote it not sticking to the aluminum skin. End result: it goes onto the leading edge nicely.

We jumped right into skin riveting after dinner tonight. Not really a lot to comment on, just more of the same stuff from the last couple of times. Only difference is that we got through the rest of the right skin tonight. I won’t quite say we’re “done” done, since I still want to go and check the shop heads. If the left skin is any indication, there will be a handful we’ll need to go back and hit up a touch more. But enough is enough for tonight.

Finished* right wing top skin:

I did make a slight boo-boo on one rivet. Guess I held the gun at a bit of an angle and put a little smiley face dent under the rivet. No worries though, it’ll disappear under the paint:

Unsurprisingly, the main task of the day was to keep going on skin riveting. Around early afternoon the left wing was all done:

Well, except for those clecos at the bottom. Those are the skin-spar rivets, and they’d be tough to get to in this position, but are accessible with the squeezer. So I figure I’ll just squeeze all of those after I get the wings off the stands and in the cradle.

The seam between the two skins doesn’t quite sit flush though. It occurred to me as I was clecoing these skins in place prior to riveting that maybe I should roll the edge of that top skin a bit. Some research indicated that other builders were about 50-50 on doing this, but the most important thing I learned is that you have to roll the edge before dimpling. So that particular ship had already sailed, nothing to do but shoot as-is and hope for the best.

It’s really not that bad, and I imagine it’ll disappear under paint:

Later in the evening, we got through about half of the rivets on the right inboard skin before deciding that it was time to call it a night. Amusingly, around this time we also noticed that Dude had laid down and gone to sleep out in the garage – while we were shooting rivets. Even though the Mutt Muffs block out sound, that’s still quite a racket to sleep through:

In other news, I took advantage of more good weather to do some wood-cutting to prepare for building the wing cart. We made a midday trip to Home Depot for supplies and material, and I should have everything I need now. I made the cutouts in one end of the cart for the leading edge to fit in, and cut some of the 2×4 and 2×6 braces that also go on those end pieces. That just leaves me needing to cut four 2x6s to length after I take apart the wing stands, and to make a few more corner braces from other wing stand scrap. I figure that with the days starting to get longer again, I can always bail out of work a little early one day this week so I can make the last cuts while it’s still daylight.

So after last night’s back riveting debacle, I posted over at VAF to ask for help with the technique. Turns out the main issue is really cranking up the air pressure to the rivet gun. I’d turned it up a bit last night, but just a touch, like the change I make when shooting -4 rivets instead of -3s. Seems I need a lot more juice than that to overcome the extra mass of the long rivet set.

After work we went to an AOPA safety seminar, which lasted until 9 or so. After that, I decided to practice some to try and get the hang of the technique. I used a scrap stiffener angle and a chunk of my junk LE skin, drilled and dimpled them, and then tried the back riveting. I started out by shooting a few rivets agains the back rivet plate on the bench. Sending about 80 PSI to the gun makes it set the rivets much better, though even then I have to shoot for what seems like a really long time.

Once I’d set a couple that way, I clamped my practice piece in the vise and had Josie come out to hold the big bucking bar while I shot a few more, to better represent the real application of the technique. I smeared a few of those rivets, I think partially due to the work piece tending to move around and partially due to me being a little sloppy.

Bottom line, I feel way better about the back riveting technique, so we’ll give it another try tomorrow night.

I also drilled out (for the third time) that bad rivet from last night. Upon checking the hole afterwards, it was clearly oversized by this point, so I went ahead and drilled it out to #30. That’ll get a NAS1097 rivet…which should be fun to back rivet…but whatever, we’ll make it work.