Wings

Well, that was a lot of fun. Assembling the ailerons starts off deceptively easily: you attach the nose ribs to the counterweight with blind rivets. Then the nose skin goes on, followed by the trailing edge skin, and this is where the fun begins. The top of the trailing edge skin is attached to the nose skin and spar with solid rivets, but even with the bottom of the skin not clecoed to the spar, access to the inside is pretty tight. I must have spent half an hour just trying to figure out how to position the aileron so I could get the riveting done. In the end, my solution came from reading Jamie Painter’s build log, not my own ingenuity. You just put the aileron on end and now you can (relatively) naturally access both sides:

Even so, bucking has to be done by feel. But I got the hang of it pretty quickly, until I got to a rivet that was close enough to a stiffener that I couldn’t use the tungsten bucking bar. It took three tries to rivet that thing, and I ended up having to draft Josie to hold a flashlight and hold the skin while I worked. Removing the first two bad rivets marred the skin around the rivet head too, but hey, that’s what paint’s for…anyway, getting that one stupid rivet took probably half an hour total. But finally, I had all those top rivets done:

I’d kind of hoped to get this thing finished tonight, but oh well. It wasn’t for lack of trying, that’s for sure. The good news is that things should be easy from here on out; the rest of the rivets on the aileron are either accessible with a squeezer or are blind rivets. I imagine I’ll have this thing wrapped up pretty quickly tomorrow, and hopefully riveting the left aileron will go faster now that I’ve worked out the technique for the most part.

And once again, not the most productive day. I had held out some slim hope of priming flap components today, but that was obviously not workable, given how much prep I still have to do on that stuff. So rather than try to do that, I went back to the left aileron. I’d been under the impression before that it’d be really simple to finish this thing up, and that was kind of true, but as usual there were some small things that slowed the process down.

With the top skin/spar joint riveted, the next step is to install the end ribs. There’s a specific riveting order in the instructions for this part of the assembly which I neither remember exactly nor care enough to go look at the instructions to relate. Once you start working on rivets on the bottom, though, it’s important to secure the aileron to a flat surface to keep it straight. The instructions call for weighing the aileron down, but I didn’t have anything good for this purpose. Since the aileron naturally sat nice and flat on the surface, I just took a short piece of scrap wood and lightly clamped the trailing edge down to the surface. Then I just kept checking that the aileron was sitting flat during the following steps.

Aileron secured on the flat surface:

Before long, a lot of rivets had been squeezed and pulled and I had a finished aileron:

Next, I installed the hinge brackets, torqued the fasteners, and added torque seal:

This part of the process took way longer than I expected. As seems to be common, access to the bolt heads was limited, especially on the forward side. At one point I tried turning an old deep socket into a thin wall socket with the bench grinder, but it didn’t work out too well. I eventually ended up holding the bolt heads with an adjustable wrench,

Now, where to store this thing? I guess I’ll just temporarily attach it to the wing. I just put the bolts through the brackets and lightly installed a lock nut; I haven’t bothered with the various washer stickups and spacers that will be in place for the real assembly, though I’ll need those before I can get to fitting the flaps down the road.

At this point I broke for dinner, and after that it had cooled off rapidly in the garage, so I called it a night. Tomorrow I should be able to finish the right aileron and get to some flap work.

Did all the riveting on the right aileron today. It sure goes a lot faster the second time around… I did have a heart-stopping moment while riveting the top spar-skin rivets though. As before, I had the aileron standing up on end, and I was almost done, just three rivets left to go. I turned to grab another rivet, and when I turned back, there was my aileron, toppling ungracefully over. Unmindful of my cries of dismay, it rebounded off my work stool and plunked to the concrete. Fortunately, it was undamaged. I figure that between the stool breaking its fall a bit and it landing on the nose skin – which was reinforced by the counterweight – I got off lucky.

There are a lot of blind rivets in the ailerons, which means a lot of rivet stems left over after everything is done:

Once I had the aileron done, I mounted on the wing as with the left one. Next I went to work putting the appropriate washers and spacer in place at the hinge points. The outboard hinges are easy, requiring only washers, but the wider inboard brackets require a spacer to be fabricated from aluminum tubing. This isn’t a complex process, but it is painstaking, carefully shortening the cut piece of tubing to the proper length for a snug fit.

Here’s the inboard bracket and the washer and spacers and such in place:

Both ailerons in place on the wings:

Next I decided to work on the aileron pushrods. I started with the shorter rods, which connect the bell cranks to the ailerons themselves. These pushrods are made from steel tubing, with rod ends riveted into the ends. I spent a fair amount of time carefully cutting the provided tubing to length and then laying out the rivet hole locations – no prepunched holes here! After drilling everything, it was time to rivet.

Riveting these pushrods seems to be a frequent source of consternation for builders. The rivets are very prone to folding over when driven, making for ugly shop heads. I chose to use shorter rivets than the plans call for, and I figured it couldn’t be that bad…wrong. The first rivet I tried with the squeezer clinched in nasty fashion:

The problem was immediately obvious: I’d tried this with the squeezer held in the vise and me holding the rod in my hand. I imagine the rod rotated a bit when squeezing. That wasn’t too smart of a way to do this.

I decided that there was no way to hold the squeezer and the rod steady for this procedure, so I decided to try the rivet gun instead. I clamped the pushrod in the vise with the rivet as close to the jaws as possible. This worked great on the first two rivets, and for a moment I thought I’d cracked the code.

Nope…the next two clinched despite me being really careful with the bucking bar. So I drilled those out and then decided to call it a night. I was getting into the mindset where I really wanted to solve a problem, at the expense of really thinking through the options. That’s the kind of mindset where I tend to make problems worse.

So I’m not really sure how I’ll handle this. I’ve seen where guys have set the rivets using a C-frame, but I don’t see how that will make the rivets any less likely to clinch. The plans mention the option of welding the rod ends, which I guess I could do, though it seems kind of ghetto to do that after drilling the rivet holes. Another couple of builders have addressed the issue of the rivets bending inside the hollow rod end by filling the rod ends with something like JB Weld to hold the rivets better. I thought about doing that, but it’ll be a little messy since I already drilled the rivet holes.

So who knows…we’ll see.

Not a lot of time tonight, but I figured I’d see if I could get the pushrods done. The epoxy was cured nicely, now to get those rivets out:

That turned out to be a fun exercise. I was able to get all the rivets moving in their holes with a little touch from the rivet gun, but extracting them was a little more difficult. As usual, the first one took quite some time to get out, but then I had a system down and the other five came out in no time. I was pleased to find that shooting the rivets now was a cakewalk, with hardly any tendency to clinch. The resulting heads aren’t the best I’ve ever done, but perfectly adequate:

Next, as a precaution, I decided to shoot some primer on the ends of the pushrods. Cutting the rods to length had removed some of the powder coat, and I’d also seen some flakes coming out from under the rivet shop heads as I shot them, so better safe than sorry. I wrapped the threaded portion in masking tape and went to town:

I like how fast the 7220 primer dries. Ten minutes later and I ripped the making tape off and installed the rod ends and jam nuts:

After that, I may have pinned one of the pushrods to an aileron and then moved the rod so I could watch the aileron move. This is strictly a rumor, totally unconfirmed…

In other news, my minor griping last night about Van’s not notifying of shipments was premature. Today I got a notification from Old Dominion with my shipment info, including a tracking number. Now I get to spend my time refreshing the tracking page three times a day. I imagine I should have the kit early next week. I won’t have the flaps done by then – I’m out of town at least one day this weekend – but that’s okay. I suspect some serious garage reorganization is going to be in order once we start unpacking the fuse kit.

Rather than mess with deburring flap skins – which I won’t be able to do any priming on this weekend anyway – I decided to go ahead and build the second set of aileron pushrods tonight. These are the long pushrods that will run between the bell cranks in the wings and the control stick in the cockpit. These are simpler to make than the other ones as well; instead of small-diameter steel tubes with solid rivets, these are fairly large-diameter aluminum tubes and the ends attach with blind rivets.

Once I’d cut the rod stock to length and marked and center-punched the hole locations, I got Josie to come out and hold one end of the tube while I drilled the pilot holes in the drill press. Next I inserted the threaded ends, lined them up carefully, and drilled all the holes out to full-size, clecoing as I went:

Some quick deburring of everything and then it was just squeezing a bunch of blind cherry rivets. Afterwards, I couldn’t resist the urge to install a bellcrank and both pushrods, just so I could sit at the wing root, move the pushrod, and watch the aileron move:

The next time I do some priming, I’ll go ahead and shoot the outside of these rods as well. I figured it was easier in this case to just prime after assembly instead of before.