Finally, a good productive day. Haven’t had one of these in some time. I started the day off with a trip to Home Depot to pick up my conduit materials. I was sort of hoping for some Class 200 PVC, but I ended up with PEX instead. The Class 200 PVC is very thin-wall, generally used for vertical runs from water heater pressure relief valves. It’s only used vertically since the walls are so thin, and it can’t support much weight. But that also makes it far lighter than normal Schedule 40 PVC, and it would be perfectly suitable for my conduit run. Unfortunately, Home Depot didn’t have any other than some short prefab lengths in the water heater section. I need a 10’ run, and I don’t much feel like going to the trouble of buying several short pieces and joining them together. So I went with 3/4” PEX instead. They even had nice 10’ precut sections, exactly what I need. I also picked up some hangers, which I’ll use to secure the PEX to the ribs with pull rivets.

Back at home, I wanted to do a rough run of the PEX through the assembled skeleton I had just to double-check everything. I even went so far as to mock up both the aileron pushrods with the rod ends and put them in place, so I could see what everything would look like. Here you can see the bellcrank assembly, the small pushrod that runs from the bellcrank to the aileron, and the long pushrod that runs from the bellcrank to the control stick. Below the short pushrod is the PEX pipe, sitting in one of the hangers and temporarily clamped in place.

A closer detail of where the PEX and the pushrod cross paths. There’s a couple inches clearance in here, and the worst case I can envision if the PEX were to come loose of the hangers would be for it to rub against the pushrod. I can’t see any way it could cause a control blockage issue.

On another note related to plumbing, I’ve decided to stick with just this one conduit run. The consensus I’m getting from reading VAF experiences is that I shouldn’t have any issue running coax for the NAV antenna in with everything else. The main source of interference people seem to report is from HID landing lights, and I suspect that by the time I finish this, LEDs will have dropped in price enough that they’ll be the best choice.

Now that I’d satisfied myself with the plumbing, I decided that since I already had the whole skeleton clecoed together on the bench, I might as well go ahead and match-drill the spars to the ribs. I made a somewhat unpleasant discovery in the midst of this though – it seems that the garage outlet circuit isn’t up to powering both the compressor and air conditioner. Which is kind of odd – I’d thought this might be an issue before, so I made a point one night of running both at the same time, and I had no issues. No such luck today though…I’d gotten through a few holes when the compressor kicked on briefly, followed by darkness and a deep silence caused by my music stopping as well. Well, time to go reset the breaker. Fortunately, the garage seems to maintain temperature fairly well for short periods while the A/C is off. I guess I’ll just have to be sure I turn it off before I do a bunch of drilling.

With the ribs match-drilled, I now need to keep track of each rib’s position on the spar. Most likely I could switch them around with no issues, but it’s good practice to be sure. On the tail, I used a simple system of punch marks for this, but here I have far more ribs (14 per side to be precise). I went full nerd on this topic and devised a binary marking system. Doing it this way means that each rib only needs four punch marks; I just number them from inboard to outboard. Hopefully these marks don’t disappear under the primer…

Here’s an example of a mark. This is 0111, which is #14, or the most outboard rib. It’s hard to see, but there’s one “low” punch followed by three “high” punches.

Finally, after taking a break inside for some dinner, I set about finishing the evening by doing my last row of tank attach countersinks. Not really difficult work, though I was cognizant of how long it had been since I did this last. I got back in the groove pretty quickly, but still, I’m way more confident doing stuff like this when I’m in practice. I’d better keep up the work!

Finished row of nutplates:

Tomorrow I think I’ll make another Home Depot run for some 1/4” plywood. I want to make templates so I can drill the rivet holes for the conduit hangers. I also need to get another pack of five hangers; I forgot to count the ribs before I went this morning, so I guesses at the number of ribs and came out a little low. If I can get those holes drilled, I can make a final debarring pass on the ribs and start thinking about priming them and riveting the skeletons together! Which also means I need to start thinking about building my wing stands…

Not really so much of a work day today, more research and head-scratching. I spent some time searching around for how other builders had done their wing plumbing, then went out to the garage to try and visualize things a little better. The big concern here is the control system for the ailerons; obviously I can’t have the plumbing interfere with flight controls.

The “standard” Van’s instruction calls for running black ribbed conduit for the electrical stuff, and using grommets through existing tooling holes for the pitot lines. However, this setup has some downsides in my opinion.

• The ribbed conduit will probably be more difficult to route wires through since the interior isn’t smooth.
• Running the pitot lines through grommets would make replacing those lines a potentially unpleasant task; not that these lines wear out frequently or anything, but why complicate things unnecessarily?
• Speaking of unnecessary complications, why have three separate line runs? I don’t see why the pitot lines would need to be separated from the wiring.

Considering all these things, I was leaning towards skipping the conduit and instead running something like 3/4” PVC or PEX through the existing lightening holes. Several builders have done this, and it seems simpler than drilling holes to run conduit through. But this also puts the conduit further into the wing interior, which goes back to the “don’t interfere with flight controls” issue.

To give myself peace of mind, I decided to mock up the aileron control system in the left wing. I already had the main spar sitting on the bench with the ribs clecoed on, so I got out the rear spar and clecoed that in place as well. Next, I loosely put the aileron bell crank in place. This piece converts the side-to-side movement of the main aileron pushrod (which attaches to the control stick in the cockpit) to forward-backward movement of the smaller pushrod that directly actuates the aileron. The smaller pushrod was my main concern, so after putting the bell crank in place, I laid the rod in place using the bell crank and the rear spar passthrough holes as references.

This confirmed what I pretty much knew anyway: The small pushrod sits towards the top of the wing, and leaves plenty of room to run 3/4” tubing through the second lightening hole at its lowest point. I’ll probably go ahead and get the tubing I’m going to use tomorrow or this weekend just to make really really really sure it’s OK.

The only thing I haven’t really accounted for is possibly wanting a second, isolated wiring run. I’m debating whether I’ll want to put in a wingtip VOR antenna at all. I intend to have this plane be IFR certified, and while it doesn’t seem that a VOR antenna is required, it might be prudent to have one as a backup to GPS. That, in turn, raises the question of possible noise from the electrical wiring. I’ll need to keep researching to determine if this will be a problem. For the time being, though, I think the single conduit run will probably be just fine for everything.

Actually, that title isn’t 100% accurate. Really, this whole time I’ve been talking about all the deburring, I’ve been referring solely to the really tedious part: that is, getting into all the little nooks and crannies in the ribs with a needle file to make things nice and smooth. It’s the kind of work that makes your eyesight wander a bit when you stop, because it’s been a while since you looked at anything more than a foot away from your face.

But hey, it’s done! I went through all the left wing main ribs today went cross-eyed about five times, but got through. The reason I say the title isn’t 100% accurate is that there will still be more deburring; all the rivet holes will need a pass once they’ve been match drilled and dimpled and so forth, along with whatever holes I drill for wing plumbing; pitot lines, electrical conduit for wingtip lights, etc.

That brings me to the other thing I worked on today, trying to plan all the wing plumbing. I could theoretically drill the holes for this stuff after putting the wing together, but it’d be a lot easier to drill the ribs while they’re not attached as opposed to working inside the partially-assembled wings. So I’m working on planning all the stuff I’ll need to run lines for, and then I have to decide where to run the lines, making sure that I don’t interfere with the aileron pushrods or anything (control jamming is A Bad Thing).

So now I’ve got a sort of worksheet going so I can go forth and research. What pitot do I want to use, and should I get a heated one? I know I want an AoA system, but which one? The Dynon system, for example, requires a specific pitot tube, but I’m not sure if I want an EFIS-integrated AoA. AFS makes a good standalone system, but it looks like it’ll require a second pitot tube (I could be wrong, I haven’t fully researched this). Of course I’ll need wire runs to the wingtips for nav lights. Do I want to put landing lights in the leading edges? Aveo Engineering’s ZipTips look really slick, but I hear they’re Expensive with two or three capital Es.

So yeah, lots to think about. In the meantime, after finishing up all that deburring, I clecoed all the main ribs to the left wing spar. The rationalization I made for doing this was to help me visualize wiring runs and such, but mostly it was so I could step back and cackle a little.

Finally back out in the garage again today. I’m glad I got my portable air conditioner set up out there, because the Houston summer is starting to kick in…

For my first trick, I wanted to work out some good means of storage for the wing skins. Back in Georgia, I just drove some finishing nails into the wall and hung the skins by the rivet holes. It worked, but not particularly well. God forbid I needed to get the wing skin in the back of the stack…I’d end up messing up a couple nails along the way, and the whole thing was a huge operation.

I had some scrap lumber sitting around from building the workbenches, and after rolling ideas around in my head, I came up with my idea. Basically, it’s just two units with a vertical piece that leans back a bit, plus a bottom lip for the skins to rest on. I put them on the floor a good distance apart and the skins just naturally rest on them. It’s kind of like a two-piece easel, I suppose.

With that out of the way, I finally unwrapped the main spars from their bubble wrap cocoon, still left over from the move. I have one more row of fuel tank attach nutplates to do, but today I decided to instead go with the more unpleasant task – rib deburring. It’s tedious work, but it needs to get done.

So I sat down and managed to deburr all the leading edge and tank ribs for the left wing. The end of debarring is in sight now; all I have left are most of the main ribs for the left wing. Once I finish those, then I’ll be on the road to putting the wing skeletons together, though first I’ll need to figure out what I need to do for wire runs to the wingtips and such, as well as clean and prime those ribs. Still, it’s good to be working again, and also to know that soon I’ll be hitting on of this building phases where, after a long period of not much getting done, suddenly I have assemblies that look like actual airplane parts.

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…