Today seemed like a “getting back in the swing of things” kind of day. Which makes sense when you consider how long it’s been since I’ve done regular work. Anyway, I decided today’s project would be to pollute the newly-cleaned garage with lots of aluminum shavings by getting to work countersinking the left spar. I got all the tank attach nutplates done on the bottom of the spar; still have to do the top. That should go by faster than today; today I was trying to take my time and be careful and so forth.

I still have to finish deburring all the left wing ribs as well. Pretty soon I’ll have to start thinking about cleaning and priming all those ribs…

Wow, it’s really been two months since I did any appreciable work on the RV.  It started with some craziness at work…we had a big pressing project, which worked out to some long hours and a fair amount of stress.  But even that really calmed down for the most part about a month ago, but I think I was still having some residual stress issues.  I tried to go out in the garage and deburr some of the right tank ribs one Saturday, but it just seemed like horrific drudgery that I didn’t want to have anything to do with, so it didn’t take me long to find an excuse to go back inside.

I guess you could say that I was really in need of a vacation.  Luckily, there’s Oshkosh!  This was the second year for Josie and I; we drove up last year, and I pretty quickly concluded that the next trip should be flown instead, so that’s what we did.  We rented my favorite Archer from Skybound Aviation and headed up for a full eight or so days camping up in the North 40.  I think it was just what I needed; I came back with a clearer head and a much better attitude towards life in general.

So anyway, today I went out in the garage and went to work on those tank ribs again.  This time, there was none of that feeling of drudgery.  Well, it’s still tedious work, but I didn’t have the same feeling of complete detachment the whole time.  Today, I got all those right tank ribs deburred…that completes all the right wing ribs. (now I just get to repeat this exercise again…)

After that, I did one of what I’m going to start calling Sanity Assemblies.  These are temporary assemblies of parts that serve no purpose other than to let me look at and touch something that looks like a real airplane part.  For today, I used the leading edge cradle that Daniel Schoning gave to me and clecoed the right tank together.

That’s all for today.  I still need to countersink the second main spar and get those countersunk holes primed…maybe that can happen next weekend.  Plus there’s the left wing ribs to deburr as well…

Wow…between things becoming crazy at work, and getting some kind of stomach bug, it really has been 2.5 weeks since I touched this project.  Even today, I slept in pretty late in an attempt to recover from a long and stressful week at work, and then spent some time fixing up a side project of mine.  I did resolve to do something out in the garage today though…so I went out and got to work on the right leading edge ribs.

Deburring these things is tedious.  I’d already taken care of all the big edges previously with the bench grinder and die grinder, but all the little nooks and crannies need attention.  The leading edge/tank ribs in particular have lots of these, especially on the nose of the rib.  Oh, and the instructions say to pay special attention to this area to make fitting the skins easier.

I ended up figuring out a pretty decent method, using a couple of mini files and one normal one.  I’d use a mini flat file to hit up the small straight areas, then use a rat tail file to work the corners and such.  That still left the nose area a little rougher than I liked, so I ended up using a normal file to really work the nose area down and get it smooth.

I’m probably going overboard with this stuff, but better to do it right the first time.  Plus I just feel better about my work this way.

Wow, that actually went pretty fast.  After all that rib-straightening drudgery, it’s nice to be able to go out in the garage and really feel a sense of accomplishment in a fairly short period of time.  It helped that I basically had all my tools set up and ready to roll after my test piece from last night; I had one countersink cage set up with a #40 bit, adjusted for the flush rivets, and the other set up with a #30 bit, adjusted for the screws.  That let me basically just rock & roll through tonight’s work without a lot of the time-consuming trial-and-error setup stuff.  Very nice.

Anyway, last night I got about half of the rivet countersinks done on the bottom spar flange before knocking off for the evening.  Tonight, I went out and finished that flange, then flipped the spar around and did the rivet holes on the other side.  As I mentioned/planned last night, I then riveted a single nutplate in place and did a single test countersink for the screw, then put my tank skin substitute piece in place.  Perfect fit!

I got into assembly-line mode from there.  Basically, my procedure went like this:

• Insert a cleco into one rivet hole for each nutplate
• Lay a nutplate on top of the spar flange by each hole
• Use the previously inserted cleco to cleco each nutplate in place, aligning the other hole
• Drop a rivet into the second hole for each nutplate
• Go back down the line, pressing the rivet down while unclamping and reclamping each cleco.  This was my way of ensuring that the nutplate was well-placed.
• Squeeze the previously placed rivets
• Remove the clecos and replace with rivets
• Squeeze the other rivets
• Lay the spar down (for better stability) and countersink the screw holes

In this way, I riveted all 60 nutplates and did all the screw countersinking in under an hour.  Very nice.

Once I get the tank attach nutplates on the other spar, I’ll need to go back and prime all those countersinks, since the bare aluminum is now exposed.  That should work out nicely; I can easily get the other spar done this week, and have Saturday to prime the flanges.

In other news, I talked to Daniel Schoning this weekend, and it just so happens that he’s wrapping up his wings and will be done with his wing stands any day now, which he’s offered to give to me.  The only issue is that he had his stands bolted to his garage floor; between not owning this house and wanting to be able to move the wings around to keep the garage functional, that’s not going to work for me.  But he suggested just mounting them on a rolling cart of some kind.  I think it’s a good plan, and it’ll save me some fabrication.  His only condition was that I donate them to another RV builder when I was done.  I can handle that.

Started out today by doing some rib deburring.  Josie got about halfway through the main right wing ribs last weekend – just touching up the little nooks and crannies – and we’d left the stack sitting on the workbench.  I was planning on getting rolling on spar countersinking, which would require the bench, so I decided to just sit down and finish that stack up so I could get them back on the shelf for storage.  Man, if I thought the tedious repetitive stuff was done when I got the last rib straightened, I was wrong. (for the record, I thought no such thing, and I only mention it here for the purposes of rhetoric)  Just sitting there with a couple of needle files, filing, checking, filing, checking, filing… whew.

That done, I brought over the first wing spar and clamped it down on the bench.  Like other parts, the holes for the nutplates are undersize, so I started by reaming the rivet holes out to #40.  That was easy, but then I wasn’t sure about what size the screw holes needed to be.  I got out a #27 bit and drilled a test hole in some scrap, but found that wasn’t big enough.  On the other hand, the #21 bit looked too big.  I sure didn’t want to go hacking up this beautiful spar.  Then it occurred to me that I might not even need to drill those holes to final size anyway.  The procedure specified in the instructions is to rivet the nutplates in place, then use a #30 countersink for the screw hole; that bit will center nicely inside the threads of the nutplate.  Using this method, in turn, means that it’s not necessary to get the hole to final size for the countersink bit to center, since I’m not actually using a #8 screw countersink.

Of course, the screw still has to go through there, but it’s possible that by the time the countersink is deep enough to accept the tank skin, it’ll be deep enough that the hole is large enough anyway.  It was time to put together a test rig.  First problem: there’s no raw material in this kit that’s the same thickness as the main spar channel. But it turned out that the piece of angle aluminum I bought for aligning the trim tab was the perfect thickness…nice!  So I sawed off a section and proceeded to rivet a nutplate in place.  Then I got a piece of scrap sheet the same thickness as the tank skin and drilled and dimpled it for a #8 screw.  This is necessary to get the countersink right, since it accepts the dimpled tank skin, not the actual screw.  With a bit of trial-and-error, I had the countersink right, and wouldn’t you know…it was deep enough that the hole was bigger than the screw.  So after about an hour or so of work, I’d convinced myself that I didn’t actually need to find the right drill size for the #8 screw.

Here’s my little test setup.  Still need to get the countersink a little deeper; the skin piece isn’t sitting flush…

(I did, however, note that the screw holes in the tank skin are undersize…so I’m going to have to figure this out/get the right bit before too much longer…)

Finally, I went to work with the #40 countersink, working on the nutplate rivet holes.  I got through about half of those on the bottom of the spar before dinner arrived in the form of pizza delivery, which seemed like a good time to stop for the evening.  Tomorrow I should be able to get into a good rhythm, knock out the rest of the rivet countersinks, and then start riveting nutplates on.  Even though I went through those complex testing machinations, I think I’ll start by riveting a single nutplate and then countersinking, just to make sure that there’s not a hole size issue in the real thing.  Worst case, I have to drill out a single nutplate…no big deal.

Some of tonight’s countersunk rivet holes:

At this rate, it won’t be long before I’m riveting the skeletons together and hanging them on the yet-to-be-constructed wing stand!

Yep, sat down right after getting home from work and took care of the last ten before heading out for dinner.  I’m glad to have that behind me, though there’s stil the drudgery of deburring these things…oh well, a little bit at a time.