Tonight I just worked on the cockpit rails. Well, first, I cleaned up from last night, since I left tools out all over the place after finishing the rotisserie.

About a third of the cockpit rail rivets are accessible with the squeezer; the rest obviously have to be shot with the gun. This is slightly challenging since there’s only a small flat area around the rivets, then there’s a bend that has to be worked around. All in all, though, the riveting was pretty easy, especially with the new ability to rotate the fuselage sideways. I’m pretty sure this would have been a lot less pleasant if I’d had to lean over the rails to rivet.

The only real challenging part was the area where the seatback support plates are already in place. After checking the construction manual, I realized that the original build sequence is to rivet the cockpit rails first, then the plates – so I kind of did this out of order. That would have provided much better access to the rails, but also would have made it a lot harder to rivet the plates. It actually wasn’t that tough riveting under the plates, but I had to get creative to buck them. Somewhat amusingly, I don’t think this is the first time I’ve duct-taped a bucking bar to a stick:

There was also another issue that came up here. On the left side of the cockpit, the longeron sits a bit low, and as a result the mid side skin sticks up just a hair above the cockpit rail. By the time I realized the consequences of this, it was too late – I’d put a nice series of dents in the skin while riveting the rails:

Fortunately, I was able to do a decent job smoothing the area out with the rivet gun, and then I filed down the excess skin a bit. It’s not perfect, but it looks much better now. I believe this area will eventually be covered by the canopy skirt anyway:

Finally, I masked everything off so I could shoot the interior paint on the rails. I’s previous debated whether to paint this like the interior, or maybe have it match the exterior – obviously, I decided on the former.

The rotisserie really came in handy here. The texture paint shoots best on a vertical-ish surface – easy to do with the rotisserie, basically impossible otherwise. The finished product:

This does present an interesting problem for tomorrow – this texture paint takes a while to dry. I usually try to leave it alone for a couple days at least. The next task is mounting the seatback support, which involves working in the same area. More notably, it involves shooting some more flush rivets on the rails, which I didn’t think of before painting – I was mostly thinking it would be easier to mask for paint without the support in place. I’ll probably just skip shooting those rivets for a week or so to let the paint dry, and even then I suspect I’ll have to do some touch-up afterwards. Oh well.

Tonight’s goal was pretty simple: finish the rotisserie. And I did it – slightly more tedious than I expected, but it turned out pretty nice. First on the list was to drill the engine mount holes to 3/16” through the firewall to attach the frame. There are prepunched holes in the firewall for these, but the spacers just behind them have a seam right in the middle of the hole. I wasn’t confident I could drill from the front and keep the bit from wandering. Fortunately, there are also prepunched holes in the weldments inside the cabin, so I drilled from there instead. It was a little more annoying working inside the cabin, but it worked great.

Next up, I cut the two angle iron pieces for the vertical frame pieces, drilled the top and bottom holes in each, and bolted them to the firewall. That was straightforward, but now came the fun part: the horizontal pieces. I wanted to line these up carefully to put the center of rotation in the center of the firewall. Well, not exactly the center per say, but the point equidistant from the “corners” of the firewall. This was to ensure maximum clearance when rotating the fuselage. I’d laid out this center point yesterday, and so today I used that as a reference to position the lower horizontal angle. With that clamped in place, I drilled the holes to attach it to the verticals, then used those holes to lay out the bolt holes to attach the angle to the engine stand mount plate. I used those holes, in turn, as a template to drill the same bolt holes in the upper horizontal.

Finally, I bolted both horizontals to the engine stand plate, then bolted the lower horizontal to the verticals. After leveling everything carefully, I drilled the last two holes to bolt the upper horizontal to the verticals, and added the bolts. Everything got torqued down for good measure, and it was ready to go into the engine stand base:

Looks great, but there’s one problem: the angles are a bit too wide, and the mount plate unit can’t slide far enough into the base to allow me to insert eh locking pin when I’ve rolled the fuselage to the desired position:

I actually started to quit of the night, thinking I’d need to trim the angles somehow, but then it occurred to me that there was a ridiculously simple solution: just drill a new hole in the base for the pin, allowing the plate to sit a bit further out:

To roll the fuselage, I just move the tail sawhorse so the tailspring is sitting on it and acting as a pivot point. That sawhorse already has a v-shaped cutout, so the tailspring naturally remains in one spot (other builders have mentioned needing to make sure the spring doesn’t roll off the sawhorse). Then I can roll the fuse to any position I need:

Now I can get back to riveting those cockpit rails!

Last night, I mentioned thinking about going ahead and building a rotisserie for the fuselage, and I hadn’t changed my mind by the time I left work today – so I stopped by Harbor Freight on the way home and picked up a cheap 1000-pound engine stand. I also went by Home Depot to get some pieces of angle iron and a few bolts and nuts.

The general idea of the rotisserie is to go ahead and drill the engine mount holes out to 3/16” (not their final size) and use these to attach the angle iron in such a way that the firewall can then be attached to the engine stand. The tail can simply be supported by the tailspring, and the fuselage is turned by simply turning the engine stand.

The first issue evident once I got the engine stand assembled was that the upright wasn’t vertical – the digital level actually showed it off by about 3°. In order for the rotisserie to work properly, I want it to be pretty close to dead vertical. So began a long series of tinkering with the thing, trying to figure out ways to straighten it. There’s no kind of adjustability for this, so basically I just started figuring out ways to reassemble it incorrectly that would tweak the angle. But nothing seemed to work right, and eventually I resigned myself to needing to buy some more hardware to make this work.

I’d given up for the night when I had another idea for tweaking the thing – and this time, it worked. The upright is now just .3° off dead vertical, which I figure is close enough for government work. So tomorrow or Friday, I should be able to attach the angle iron pieces to the firewall and get this thing put together. Then I can finish riveting those cockpit rails…

Finally, with the fuselage back upright, I can start moving forward through the construction manual again. I’d figured I’d get the cockpit rails riveted – or mostly riveted – tonight, but there ended up being more small things to do than I thought.

First up was finally torquing the two lower bolts which attach the seat ramp angles to the center section. These bolts have been loosely installed for some time; they weren’t tightened because they had to be periodically moved to allow for shooting rivets. The rivets through the center section and the mid bottom skins were the last ones of concern here, so the bolts could finally be torqued. Doing this was kind of fun; holding the bolt involves reaching inside the center section, and there’s not much room in there. I ended up with Josie reaching in from the outside to hold the wrench while I leaned over into the cockpit and tightened the nuts.

Next up was installing the rear seat lap belt brackets. These slide through slots in the bulkhead webs, in between the aft lower longeron and another bracket mounted above, and three AN3 bolts hold the assembly together. The fit here is pretty tight, and I had to do some tapping with a hammer to get the brackets in place, and also to get the bolts through the holes. Getting the nuts started and torqured wasn’t much fun either – at one point I was lying on my back on strategically-placed pieces of lumber in the fuselage.

Here’s a shot of one of the brackets in place. Note the bulkhead to the left, leading to the cabin. The nuts are barely visible under the bracket. Note also how the bracket curls upward away from the fuselage skin. This made it fun to hold the bolts while torquing the nuts:

Next up, I riveted the finished floor support angles in place. This required some creativity with riveting, since the angles are close to the mid side skins, and the seat ribs also restrict access with, say, the squeezer. I was able to squeeze four of the rivets, but had to shoot the other two using an offset rivet set – and holding the gun in a weird backhand way, squeezing the trigger with my thumb.

I started unclecoing the center section bulkhead caps, preparatory to clecoing the cockpit rails into place, but I realized that the left cap needed a little work. Way back when I was working out the rear throttle linkage, I cut holes in the bulkhead web for the pushrod to pass through – well, matching notched were needed in the cap flange. I figured it would be easier to cut and tweak these holes now, without the cockpit rails in the way, so I did that:

A look at the aft notch with the cap clecoed in place (through a mirror, because there’s no way to get a decent direct shot):

Finally, I could cleco the rails in place. It was getting close to quitting time by this point, but I went ahead and squeezed six rivets on each side for good measure:

I’m pretty sure I’ll be able to squeeze most of these rivets, and the ones I can’t squeeze should be easy to shoot. The only exceptions, I think, will be the rivets behind the mounting plates for the seat back support. I may need to recruit help for those…hopefully I won’t have to lie on lumber in the fuselage to buck them. Further along in the planes are instructions for cutting plywood into work platforms for the tail – I might go ahead and make those for times like this. I’m also thinking that it might be time to go buy a cheap Harbor Freight engine stand to make a rotisserie out of – a lot of the work tonight would have been a lot easier if I’d been able to turn the fuselage sideways instead of leaning over. Actually, come to think of it, riveting the cockpit rails would also probably be easier with the fuselage sideways…guess I might be making a stop on the way home from work tomorrow.

It’s done! I got a bit ahead of myself last night be declaring all the annoying riveting to be done. It turned out there were still some challenging spots left, most notably the rivets at the lower aft end of the mid side skins, where they curl underneath to the belly. The radius of the curl is pretty small, which forced me to use a narrow bucking bar on several of the rivets, and I also had the outboard aft seat ribs in the way as well. There were a couple rivets here that we had to drill out and re-shoot – this was entirely due to me having trouble keeping the bucking bar in place due to the cramped quarters.

Once we got those done, though, it was smooth sailing. We shot all the rivets between the mid bottom skins and the aft portion of the center section (the forward line will be riveted later in assembly with the forward bottom skin). Then we shot all the rivets along the lower edge of the forward outboard seat ribs, plus a few assorted rivets I couldn’t quite get to by myself.

That just left ten rivets on each forward side skin, in the area of the gear towers. These were more fun than some of the others and required some fresh contortions. While the cabin and tail area of the fuselage is open at the top, there are two braces across the cabin at the tops of the gear towers, which I had to work around to buck these rivets. All in all it wasn’t especially challenging, just uncomfortable. I can’t imagine, though, how horrible these rivets would have been had I not done the removable gear tower cover modification. At least I had nice big holes through which to hold the bucking bar.

While I was down there, I decided to try and grab a selfie to illustrate my discomfort. Here I’m leaving against the sawhorse that’s supporting the fuselage. There’s just enough room between it and the brace for me to get my upper body in there:

But once these were done, that was it – the end of this riveting odyssey (for the time being, at least). Once I crawled out from under the fuselage and retrieved all my tools that had collected down there, we rolled the fuselage upright again, for the first time in – let’s see – three weeks. Looks much sleeker without a few hundred clecos sticking out:

I also took care of some other tasks during the day today when Josie wanted to go inside and rest for a bit (I have to remember that working the rivet gun is probably a little more physically challenging for her). I finished demurring the replacement seat ribs I got the other day, match-drilled them with the spacers that will sit on top of them, and riveted the nutplates in place. Those angles are now ready to rivet in the near future.

Most notably, I riveted the seatback support plates to the mid side skin bulkheads. I had originally planned on doing these after we’d rolled the fuselage upright again, but after looking at them while sitting under the fuselage, I decided they’d be easier to do this way. These plates were challenging to rivet, since I had to hold the bucking bar inside a cramped space between the plate and skin. At one point, I seriously considered ordering some expensive Cherrymax blind rivets to use here, but eventually I managed to get them all shot.

Next steps will be to rivet the cockpit rails in place (should be a solo job, I think), and then permanently attach the seatback support. Then we’ll roll the fuselage over once again, and it’ll be time to fit the landing gear legs!

We continue creeping ever closer to getting this riveting done. Tonight we finished up all of the really annoying riveting around the aft seat ribs and also shot a handful of rivets at the rear seat lap belt anchor points. At this point I feel like the tough riveting is behind us (for the time being, that is), and it should be downhill from here. Hopefully we can get this wrapped up tomorrow…I’m kind of getting tired of sitting on the garage floor under the fuselage…

So not a whole lot of interest to report here, just more and more riveting. Tonight we worked on the rivets at the aft end of the seat rib assembly, and I think these are probably the most tedious ones to deal with here. The understructure here is such that it’s almost impossible for me to even get a good look at the rivets I’m bucking. By itself, this isn’t a huge deal – I’ve shot plenty of rivets and just held the bucking bar by feel, but in most of those cases I had good access to hold the bar in such a way that I could make sure it was square. In this spot, it’s also hard to get my hand on the bar to hold it securely, which makes things a lot more fun.

At this point, we have almost all the rivets on the right side of the fuselage in this spot done. We stopped short of a few, simply because I could not for the life of me figure out how to get any of my bucking bars onto the rivet tail. I guess I’m hoping that maybe I’ll have an epiphany overnight or something. I’ve also considered using blind rivets here, but I don’t think I have any that have the required grip length here. Several spots in the build specify that MK-319BS rivets can be used in place of the 426-3 flush rivets, but they’re always spots where it’s just a single skin and a rib. Here I have two skins and a slightly thicker-then-normal rib, so I’m not sure the MK319-BS rivets would be acceptable.

The good news is that once we get this area done, everything else that’s left will be simple by comparison. Assuming I can figure out a way to buck these last few obnoxious rivets (or use blind rivets in their place), I think we might have a good chance of finishing up the fuselage canoe riveting this weekend.

Josie wasn’t feeling well tonight, so rather than do any riveting, I decided to work on some of the replacement parts I got from Van’s last week. First I separated the floor support angles and final-drilled all the holes. I also dug up the spacers which will sit on top of the angles, separated them, and clecoed them to the angles. I considered match-drilling the spacers to the angles and going ahead and riveting on the nut plates, but I decided it’d be better to do that once the fuselage is upright again, so I can ensure that everything fit together OK.

Next I worked on prepping the replacement forward gear crossmember. I cleaned up the edges, final-drilled the holes, and countersunk the required places. I’ll probably shoot primer on the crossmember Saturday. Finally, I got out the new cooling ramp and trimmed the edges. I didn’t do any match drilling on that though, because I decided it would be more fun to cleo it in place temporarily for fun.

Here’s the cooling ramp by itself under the forward floor:

Then I clecoed the forward bottom skins in place to get the big picture:

Hopefully tomorrow we can pick back up on the riveting!

So tonight was kind of a turning point, I think. Two-person riveting so far has been an often-frustrating experience; it seemed like Josie was just completely unable to get a handle on using the rivet gun in moderation, resulting in lots of overdriven rivets. After thinking it over, it occurred to me that it was a bit unfair of me to drop her right into riveting with little direct feedback, just me trying to coach through a sheet of aluminum. It’s a lot easier to learn riveting when you’re doing it solo and you can watch the rivet tail deform as you shoot.

So last night, in lieu if riveting the fuselage, I drilled a bunch of holes in some scrap to make a riveting practice kit. While I think that helped it still seemed like Josie was having trouble handling the gun. I was thinking things over before bed last night and realized the obvious problem – I run the rivet gun at a pretty high pressure. This gives me lots of power when I want it, but requires precise trigger control. It works great for me because I’ve literally shot thousands of rivets with the thing. It’s also about the worst setup possible for an inexperienced riveter, where an extra millimeter of trigger pull can go from “that’s good” to “I destroyed the rivet in a quarter second.”

So today, I turned the pressure to the gun way down, to where it was impossible to run the gun at a “destroy everything” level. We shot a few more test rivets in scrap and it seemed promising, so we went back to the fuselage. The results were…great. No overdriven rivets, none requiring drilling out. We didn’t get a huge number done, but I’m OK with that because everything else went so well.

To think, all this time I’ve been frustrated because I thought Josie was being careless, when in fact I was careless and I set her up for failure. Lesson learned.

Not much to report, we’re just continuing to slowly work our way through the riveting, a bit at a time. Tonight we shot most of the rivets at the joint between the mid bottom skins and the aft bottom skin. These will be some of the last rivets that don’t require interesting contortions, so I guess I’d better try to enjoy them…