Lots of stuff to do around the house tonight, but I did find time to go out and rivet the nutplates onto all the tank attach angles I primed last night. Every little bit of work helps…
Here are the angles laid out in their positions on the spar:
Another so-so weekend. Josie had to help out with some testing with her job Saturday, so I had visions of getting up early with her and putting in a long productive day in the garage. That was before I realized she’d be spending that entire time on a conference call. Her work area is right by the garage door, which I leave open while working to help cool the place. And my first task would be match drilling, which would provide a double noise whammy of the air drill and the compressor cycling, which would in turn probably have a negative effect on her call.
So I instead took care of a couple work things of my own, and also spent some time doing some long-delayed improvements to this blog. The main thing I wanted was to start tallying up the hours I’ve been logging. I’ve put this off for a long time because I frankly hate getting into the guts of WordPress. Fortunately, I found another RV guy who was using some custom WP plugins, so I grabbed one of his and made some modifications to get the behavior I wanted. So now on the sidebar, there’s a running total of hours spent overall, plus numbers by each category link. Looks like I’m in for about 360 so far, so based on the Van’s estimates of 1600 hours, I’m maybe 25% done with this thing. I’d better start getting more productive on weekends…
Anyway, I did get out in the garage for a bit Saturday evening to get the right leading edge match drilled. Straightforward stuff, nothing much to speak of. Then I got the inboard leading edge rib – the one that’s not drilled at all – fitted it in place, and drilled the holes that attach it to the spar. I then moved on to the tank joint plate. Having learned from my mistake on the left wing, I took a different approach here.
The instructions tell you to draw a line 1/2” from the edge and align this with the skin rivet holes, which supposedly will give you 11/16” protruding from the skin. Well, when I did this last time, I had more than 11/16” protruding, which I thought was normal given how the instructions were worded, and I was of course completely wrong. So this time, I disregarded that instructions and just put a line 11/16” from the protruding edge. Then, when I slid the plate into place, it was easy to get it to a point where the protruding amount was just right.
The fun after doing this is trying to get the rib aligned; about all you can do is measure the joint plate protrusion from the skin and then try to match this measurement to the rib. It’s tedious, and I was getting frustrated, and just generally not feeling like I was in a good state of mind, so I abandoned the task and went in for the night. Better that than to misdrill and botch some more parts.
Today I was in a better mood, and got that rib aligned and drilled properly pretty quickly. After checking the holes to make sure they were fine (they were), the next task was to drill the tiedown hole. When I checked the location of the prepunched hole, it seemed off a bit, so I used a needle file to move it a bit before drilling to full size. I’m to really sure I improved anything, and I suspect I may have made the situation worse. The end result was a hole that doesn’t quite line up with the tiedown bracket:
But the tiedown ring still goes in OK, so I’m OK with how things ended up:
I may file the edge of the hole around some more when I take the leading edge assembly off though; I’m concerned the tiedown threads might be cutting the skin there, and I don’t want any accumulating damage from that.
Next up were the tank attach angles. The inboard one was already drilled, but the other six still only had their center hole drilled. I went through each of those, match drilling using the prepunch spar holes, then marked each for its location. Next came the sacrificial nutplates I’ve been using as drill guides; with the nutplate attach holes drilled, I countersunk by hand for NAS rivets, then took the angles out to be cleaned and primed. Like the left angles, I masked the face that will mate with the tank, since it’ll be covered in sealant.
That’s all for today…now it’s time to cleco the right tank together and get that thing fitted!
So I stopped at Home Depot on the way home as planned and snagged a shiny new air hose. The good news is that I have a new hose. The semi-bad new is that they had only two lengths, 50’ and 100’. I got the 50’ hose, which is roughly twice the length I should ever need in this 20×20 garage. Which in turn means that I now have perpetual hose slack lying around. Might have to figure out some way to store this thing at some point…
Anyway, after dinner I headed out, grabbed the drill and #40 reamer, and went to town on the skin holes. About 90 minutes and several hand cramps later, all the holes were match drilled, and I removed and stored the lower skins. Then I pulled out the right leading edge parts, clecoed that whole assembly together, and set it in place on the spar. I was in the process of clecoing it to the spar when I ran across another clearance issue with the wing stand: the leading edge skin interfered with the upper outboard arm. The previous owner of the stands had cut a slot there previously, but it wasn’t deep enough to accept my skin.
Nothing that couldn’t be fixed with the Dremel and a cutting bit though. I took some material off the other slot on that same arm just to make sure I had plenty of clearance over there. Then I really did cleco the leading edge in place for good:
That’s it for the night. I think I’ll start tomorrow by match drilling the leading edge; that’ll free up some clecos for use on the tank. Plus I might as well match drill now instead of waiting, since I’ve got the thing clecoed in place. I know from experience that it’ll come off and go back on several times, but once match drilling is done I can just use minimal clecos to hold it in place.
OK, so not much done tonight. After eating dinner and chilling for a bit, I was about ready to head out and get to match drilling, when I remembered something: I’d meant to stop at Home Depot on the way home from work, to pick up a second air hose. All I have right now is one of those little curly jobs, which has been a bit of a stretch to get just to the other side of the left wing. It might reach all the way to the far side of the garage (i.e. the top of the right wing), but it’d probably be really tight.
Oh well. At the least the hose should reach the bottom of the right wing, so I could at least match drill that and leave the top for later. I was just starting to get set to stretch the hose over when I decided to take a quick look at the directions – you know just for funnies. And I’m glad I did, because I completely forgot to make the wing walk doubler for this wing. That’s supposed to come before clecoing the skins into place. Whoops.
To follow the instructions to the letter, I’d have to completely remove the inboard top skin, since it’s supposed to be used as a drill guide for the doubler. Well, that would be kind of a pain, so I figured out a better way. The wing walk doublers are exactly identical, so I just pulled the left doubler and used it as a template for the right one.
(Come to think of it, if I’d been smart I would have just made both doublers at the same time previously. But that’s if I’d been smart…)
Tracing the cut lines using the left doubler:
Drilling the holes using the left doubler as a guide:
Then it was just a matter of deburring the holes, putting the left doubler back in place, and sliding the right one in place as well. I decided to just call it a night instead of trying to work out the air hose issue. Now I just have to decide what hose to get. I had a nice spring-loaded wall mount reel back in Atlanta, and it was nice, but I don’t have a good place to mount such a thing here without making big holes in the walls, and since we rent…yeah, that’s a no go. I should probably just get a regular straight hose instead of another curly thing, but then I have to worry about rolling the thing up between uses. Harumph.
So my main objective for tonight was to get the skins clecoed onto the right wing skeleton. But first I had to address some other concerns; namely the very real possibility of not having enough silver clecos. I’d done a sort of quick and rough estimate Sunday night, and it was looking like my supply would be marginal to get the right skins on. So my plan was to remove some of the clecos I had holding the leading edge together.
I couldn’t recall if I’d match drilled the left leading edge yet, but I was pretty sure I hadn’t, and I turned out to be correct. So I decided to go ahead and match drill it while it was thoroughly clecoed, then remove about half or so of the clecos. With match drilling complete, the only real purpose of the clecos would be to keep the assembly together in a minimal fashion.
But first I wanted to take a look at the leading edge rib flanges that attached to the spar. Last time I put the leading edge in place, it seemed like I had to pull a bit to get everything lined up, so I suspected that some of those flanges weren’t quite square. A quick check confirmed my suspicion, and a bit of work with the hand seamers fixed that problem. This time, the leading edge went on the spar and it lined up without any trouble. Match drilling went pretty quickly from there; the skin-to-rib holes were stupid easy, though the rib-to-spar holes required me to use a long drill bit instead of my usual reamer due to tight clearances.
Hey look, the left wing is back together again:
So I slid on over to the right wing and got to work clecoing. I’m pretty sure I said this when I did the left wing, but there are a lot of clecos here. I would estimate I spent a solid hour just on this task. I did the top skins first, then moved on to the bottom, working from inboard to outboard. I was down to the last few clecos when I noticed something wasn’t right. Oh, I see, the skin is interfering with the lower outboard arm of the wing stand.
Hrm, that’s a problem:
So I proceeded to remove all the clecos outboard of the third rib, which allowed me to pull the skin out of the way. I also had to detach the outboard spar ends from the arms so I could pivot the wing out of the way. Only then was I able to get in with a hacksaw and start cutting a notch in the arm. Some cleanup with the Dremel, and all was well again:
Of course, since I’d moved the wing around, I felt compelled to break out the plumb bobs again just to make sure I hadn’t introduced any twist into the wing while moving it. Everything checked out though, and now the wing is all set for match drilling…another night.
Finished setting up the right wing on the stand tonight. As with the left wing, there were some modifications that had to be made to the stands, but I’m pretty sure things went faster this time since I’ve done all this before. Now the skeleton is fully clamped in place, all sag and twist removed, and ready to accept the skins for match drilling.
After getting the stand all set up, I decided to go ahead and prime the tank attach countersinks, so I set about masking everything and shot the primer. Funny how the masking takes about six times longer than the actual priming…
No photos tonight, nothing really worth seeing.
Well, not much of a work day, but I got my milestone done anyways. We ran down to the coast with the dogs in the morning, and while we were down there, my allergies starting getting bad, to the point that when we got home around midafternoon, I immediately drugged myself and took a nap. I woke up feeling a bit better, so I headed out to squeeze some rear spar rivets.
Not really much interesting happened with this, though I had a couple of ribs whose flanges wanted to pop away from the spar web when I squeezed the rivets. I ended up drilling out a few rivets and working up a system with a wood block and a clamp to hold the flanges flush while staying out of the way of the squeezer. Once I got that technique down, I had pieces sitting nice and flush. I also inexplicably found a couple of empty rivet holes between the rear spar web and the reinforcement fork, which I riveted together over a year ago. I guess I somehow thought those were holes I needed to leave open for some reason. Who knows…I just squeezed the rivets in there and moved on.
There were a couple spots on the rear spar where the primer had gotten messed up, so I decided to shoot some touch-up primer. While I was at it, I took care of another task that I should have done a long time ago. The main spar is gold anodized, but the spots where it’s countersunk for the tank attach screws are supposed to be spot primed. Since I was priming anyway – the main consequence being that I turned the A/C off and opened the door (in the process realizing that Houston in August is still stupid hot even at 10 PM) – I decided to mask the left skeleton and shoot primer there too.
Lots of masking tape and newspaper:
And the finished product:
Looks a little bit ghetto, but I’m not really bothered. This area is going to be covered anyway.
After letting the primer fumes die down for a bit, I recruited Josie to help me move the right skeleton onto its stand. Now I have *two* wing skeletons!
The sag in the right wing (right side of the photo) is pretty noticeable. All I did was bolt/clamp the main spar to the stands tonight; I still need to go through the whole ritual of removing the sag, checking for twist, and finally clamping the rear spar to the stands as well. I’ll do that tomorrow night and maybe go ahead and mask the right spar and prime those countersink holes too. Might as well go ahead and get them done now.
It shouldn’t take me too long to get the right wing to the same point of assembly as the left one – I think the main tasks are going to be match-drilling the skins and fitting the leading edge and tank. Or to put it another way, I don’t think I’m going to be able to put off sealing the tanks for much longer…
This post sort of covers two days. I did get out in the garage last night, but only for about an hour. All I did was prep the replacement rib I got in from Van’s; reamed the spar attach holes to #30, cleaned up the edges, checked the flanges for squareness, fluted the thing, and undertook my favorite task of removing burr in the tight spots with needle files. I also drilled the holes in the lightening hole for the wing conduit, and finished off the night by getting Josie to help me move the right spar back to the workbench.
Saturday, the first order of business was to get that rib primed. After it was done and drying, I recruited Josie to come out and help me shoot rivets in the main spar. She also had a good (but late) idea; she asked why some of the ribs were already riveted, and I explained that with the flanges facing one way, I could easily access both sides and shoot the rivets solo, but when the flanges faced the other way, it was too awkward. She gave me a funny look and asked why I didn’t just turn the spar over.
It’s amazing the things that you never think of until someone else points them out. *sigh*
Anyway, we got all those rivets shot, and then I moved on to the two remaining inboard ribs. Before riveting those, I made use of what I’d learned about the tank attach nutplates. On the left spar, I riveted those before riveting the wing walk ribs, since I’d have a lot more room. Then I learned that I needed the nutplates out of the way so I could drill the inboard tank attach angle. Well, in this case, it occurred to me that there was no reason I couldn’t go ahead and drill that attach angle, so I did just that.
Then I set about riveting those nutplates. I didn’t have much problem on the left spar with these, but here I did much worse. I had ridiculous trouble keeping the flush set in place, and messed up two rivets. And since I was using NAS rivets here, I didn’t think I could safely drill the heads off, so instead I ground off the shop heads with a Dremel, which also messed up the nutplates.
I then took a different approach to these things. I recruited Josie once again, this time to help me back rivet those nutplates. Obviously the back rivet plate won’t work here, but really all you need is a good flat object to hold on the manufactured head side. So I just gave Josie the tungsten bucking bar, and we shot all four rivets in about five minutes, and they were beautiful.
That just left the two inboard ribs to rivet, which I easily did solo, and then it was time to bring out the rear spar and cleco it in place. I briefly considered squeezing a few rivets back there, but it was after 11 and I figured I’d quit for the night. So instead I cleaned up a bit, and of course took the requisite photo of the skeleton:
But it turned out I wasn’t done. I was about to head inside, feeling quite good about myself, when I looked at the inboard-most rib. Turns out I drilled the holes for the wing conduit mount on the top of the lightening hole instead of the bottom:
At least I still had my drilling jig around, so it was a simple matter of clecoing it in place and zapping the two holes.
I also took an inventory of my K1000-3 nutplates, which are the ones used for the tank-spar attach angles. When I grabbed the three to rivet to the spar, it didn’t seem like there were many in the bag. I wasn’t sure how many extra were in the kit, but I’d ruined two tonight in addition to the three I removed from the left spar, so there was a good chance I might be short. And I was right – I only have thirteen left, but I need eighteen for the remaining attach angles. We’ll, it’s been a while since I sent Aircraft Spruce some money.
Since I was already ordering from them, I also ordered some MSP-42 and -44 blind rivets. I’m going to use these to rivet the leading edge assemblies to the main spars instead of solid rivets; things are really tight up there, and Van’s has approved the use of LP4 blind rivets here. I’m going a step further by using the stronger Cherry rivets, partially because I already have a big bag of MSP-43s. I also ordered a tube of fuel lube, which I’ll eventually need for some tank fittings and so forth.
Tomorrow I should be able to get the rear spar riveted, and then this skeleton can go live on the stand for good!
Came home today to a nice little gift from Van’s: the prefab fuel pickup I ordered! Time to get some more work done. My goal for the night was to temporarily assemble the left tank with all the bits and pieces in place so I could verify that everything was in place for eventual assembly.
The main thing that needed addressing was the fuel vent line. First up, I needed to drill the inboard rib for the vent line bulkhead fitting. The plans aren’t picky about the location of this, so I located it as best I could off the plans and first drilled a small pilot hole. Then I clamped both inboard tank ribs together and drilled a larger pilot hole through both; this will give me consistent location of the fitting between wings. Not super important, but it assists with my neurosis of symmetry. Finally, I opened the holes to full size with a Unibit.
Here’s the left inboard rib with the vent fitting hole (top center) and the new fuel pickup in place as well:
Next up was the vent line itself. One issue here was that I’d be needing to flare the inboard end of the tubing…did I mention I’ve never flare a line like this before? Fortunately there’s lots of extra tubing, especially since I’m going to use soft lines for the pitot tube instead of the aluminum stuff, so I cut myself a test length, did some reading up on technique, and went to town. It took a few tries before I got the hang of the tool and started making good in-spec flares.
Time for the real fun. I rolled out a length of tubing slightly longer than the width of the tank itself, giving myself some extra length in case I messed up the flare and had to do it over again. This turned out to be unnecessary, as I got the flare right on the first try (it’s a little more tense when you’re flaring a 4.5’ long piece instead of some random scrap). Next I clecoed the interior ribs to the top tank skin, inserted the snap bushings, and routed the vent line through the bushings. Then the inboard rib was clecoed in place, with the vent line bulkhead fitting preinstalled. From there, it was a simple matter to make the two gentle bends needed to get the vent line to mate with the fitting.
I was feeling quite proud of myself until I realized that I’d forgotten one thing: the BNC connector for the capacitive fuel sender. That required me to remove the inboard rib again so I could drill the required 3/8” hole with the Unibit. With the rib back in, I’m confident that this tank has all the little parts in place. All that’s left to do is final drill the screw holes in the trailing edges of the skin and get the skin and ribs deburred and dimpled, and this thing will be about ready to seal.
Here’s the inboard rib with all the fittings in place:
Inside that same rib, showing the fuel pickup as well as the vent line routing to the bulkhead fitting:
And the outboard end of the tank:
Observant readers will note that the little clip I made last time is actually in the wrong place. Well…that’s what temporary assemblies are for, to figure out stuff like this. Imagine if I’d riveted that cap on before discovering this… Also, there’s obviously lots of extra material on the vent line. I thought about cutting it to length, but I want to put a little upward bend in the outboard end of the tube here to place it as high as possible. Doing so would make it difficult to get the line out, so for now I’m just leaving the extra material there. I’ll mark the cut point so I can trim it the next time this tank comes apart, and then I’ll do the final bend once everything is together for good.
On another note, I got in my replacement rib this earlier this week. I suppose I’ll get that prepped and primed this weekend, and maybe we can get the rest of the right wing skeleton riveted together in the near future. It’ll be nice to have that out of the way and more-or-less permanently affixed to the stands.
These wings are coming together fast enough now that I’ve found myself starting to consider when I should order the fuselage kit. Lead times are sitting at eight weeks, but the concern I have is storage space here. I’ll need to have the wings off the assembly stands before I have the floor space necessary to get the crate for the fuse kit in the garage. So it’ll be an interesting balancing act of ordering late enough to have somewhere to put the stuff, but early enough that I don’t end up with a bunch of downtime. Decisions, decisions…
Lots of stuff to do this morning and tonight, but I did manage to get out in the garage for a bit. After thinking it over, I’m going to order the prefab fuel pickup from Van’s instead of making my own. About the only reason to make my own is so I can do it Right Now instead of waiting a few days. Well, that and paying shipping. It would have been nice if I’d discovered this last week before I ordered my replacement rib…oh well.
So instead I started out with the tank drain. This goes on the inboard rear corner, which is the lowest point due to the wing’s dihedral and the slope of the lower tank skin. There’s already a single prepunched hole for the drain, but the rivet holes aren’t there. So the drain had to be positioned, clamped, and then used as a drill guide for the skins.
Here’s the flange clamped to the inside of the skin:
Getting that thing lined up and clamped was a bit painstaking. Right after taking this picture, I realized that the rivet holes alone the sides didn’t quite line up with the holes for the ribs. This bothered me a bit, and I almost unclamped and redid it. Then I thought if how annoying it would be to try and align the holes as well, and considered how many people were actually going to roll under the wing and criticize my alignment. Yeah, it’s fine as it is. I’m not building a showplane.
The flange actually mounts to the outside of the skin. At first I thought it was odd for this to be hanging out in the wind, but the reason is simple (and obvious in retrospect): The more the drain sticks up inside the tank, the less effective it is at removing contaminants and water at the bottom of the tank. There’s a guy who makes fairings for the drains; I’m thinking I might order and use them. If nothing else, it’ll help hide the not-quite-aligned rivets in the flange.
Here is it in place: (I should have clecoed this from the other side of the skin so you could actually see something other than clecos. Oh well.)
Next up is the fuel cap. Things are kind of reversed here from the drain flange; the large hole and the rivet holes are in the skin, while the cap flange has no holes. So in this case, the cap is aligned and clamped in place and the skin used as a drill guide. What makes this fun is that the top of the flange is curved to accommodate the curve of the tank skin, so it has to be carefully aligned before drilling:
If I thought lining up and clamping the drain was annoying, well…that had nothing on this. I think I needed about five hands to get this done efficiently, but I eventually managed to get it clamped in place:
From there, I just started drilling and clecoing. Once I had a couple of clecos in place, I could remove those bulky clamps, and everything went pretty quick. Here’s the cap clecoed in place:
Next the cap flange gets countersunk for the flush rivet skin dimples:
Then there’s one final bit to be done. The fuel vent line will run from the inboard rib all the way out here by the cap, where it will terminate just outboard of the cap. So there’s a little bracket that is riveted in assembly with the cap to hold the free end of the vent line. This clip has to be fabbed from a strip of .025 sheet. The fun part is making the little curl that the 1/4” vent line will fit into. I puzzled a bit over how best to do this, and eventually settled on a combination of a drill bit, pliers, and the vise.
For my first attempt, I stuck a 1/4’ drill bit in the vise with the base sticking out; this would be my bend guide. Then I just held the end of the strip with pliers as I gradually bent it around the bit. This made for a nice circular bend, but the aluminum has enough springback that the tubing fit a little too loosely for my preference. So I tried again with a slightly smaller bit; this time the bend was a bit too small, but I was able to force the 1/4” bit into it to size it back up a bit. After that, the tubing fit nice and snug:
Then it was just a matter of bending the free end to position the tubing nice and high on the skin, then trimming it and drilling the rivet holes. Here’s the finished clip clecoed in assembly with the cap:
At this point there’s not really anything left to do on this tank that doesn’t involved sealant. I suppose tomorrow night I can do all my hole deburring and dimpling on the skin and rivets. Before I can seal, I need to pick up some supplies, most notably MEK for cleaning mating surfaces. I suppose another Home Depot run is in order. I’m almost tempted now to keep going on this tank even after the replacement rib comes in…