My new addiction

I'm going to have to look up the location of the nearest DUA. That's Dremel Users Anonymous, for those of you fortunate enough to have not become addicted to the power one wields when using a cutting wheel spinning faster than a Formula 1 racing engine. I hear there are two types of program available for treatment of the addiction: the normal 12 step process, and for a few bucks more, a variable speed program.

I tried to quit cold turkey tonight. Really, I did! I even picked up the hacksaw and tried to use it, but...

I'm getting ahead of things. The job for tonight was to cut, fit, and install the hinges that will be used to hold the seat backs. These hinges are really nothing more than strips of aluminum with interlocking hoops through which a piece of piano wire gets threaded. Vans airplanes use them for all sorts of things, up to and including holding the fiberglass engine cowls in place. The number of places that they are used as attachments probably rivals the number of locations where they are used to actually, you know, hinge things in the more traditional sense.

The seat back attachments actually do both. Their primary purpose is to hold the seat back in place, but it is convenient that the seat backs will pivot forward a little bit when it comes time to reach behind them for the wing attachment pins. The hinge material comes in various lengths and is simply (well, not so simply as it turns out) cut to the length you need. I needed four 10" lengths. The reason for four rather than two (one for each seat back) is to allow for a little bit of adjustability. Not much, truth be told, but some.

I measured out the 10" lengths and marked a couple of the hoops that were to be removed:



A hole gets drilled in each piece 1/4" in from the horizontal and vertical edges of one side. You might be able to see the dot where I marked one of the locations.

With the measuring and marking done, the band saw would make easy work of cutting the 10" lengths. Or it would have, if I didn't own a 9" band saw.



An inch too short. Again. Story of my life. I'm hear to tell you, it has been my experience in life that size does matter. Not to worry, though, as I still have my trusty hacksaw. But boy oh boy was that taking a long time, and there was that luscious Dremel sitting right there, just calling out for me to pick it up and cut, cut, CUT!

Lord help me, I did.

And I liked it! Is that so wrong? I can quit any time. I swear it!



I drilled the holes and used them to cleco each of the hinges to the cockpit floors. The idea was to then turn the floors over and line the holes up with a line that had been drawn horizontally along the other side of the hinge. Then the existing holes in the floors would be used to match drill the hinges.



It was easy enough to see the line through the holes, but not so easy to figure out a way to secure the position of the hinge while I match drilled it. When you consider that I believe match drilling to be the best way on earth to create two holes that don't line up ever again, you can understand why I wanted to be sure that the hinge wouldn't move while I was drilling it. The best I could do was a big spring clamp.



Between the clamp and a block of scrap wood that I put under the floor to give me something to press against, the drilling went OK.



On the other floor, though...



The clamp wouldn't reach. All I could do was try to hold the hinge in place long enough to get a second hole drilled and clecoed.

I was going to keep going, but the next step was to dimple and install more nutplates.

Yeah. Not tonight. Maybe if you could do that with a Dremel...

I did trial fit the floors to the rib sections I've been building for the last few days, though. Just to see what all of the fuss has been about.

In which I get my fill of nutplates

Having had a couple of days to rest up from the four building sessions over the weekend, I was ready to replace the worn down Dremel cutting wheel and remove the piece of metal from the seat rib that had to come out to make an opening for the autopilot servo control arm to fit through. Or something related to the autopilot, anyway. I really have no idea. It's ongoing mysteries like this that keep it interesting.

The Dremel is an absolute marvel for this kind of thing. I'm not sure how I would have done this without it.



At this point, the only thing being installed for the autopilot is a doubler that (I assume) one of the servos will get bolted to. The standard rib wouldn't have been strong enough to support the torque of the big servo motor pushing against the aerodynamic forces acting upon whichever control surface this part of the autopilot ends up controlling. Hence, this relatively beefy doubler. It required a few match-drilled holes first.



There are three holes that the plans insisted be left open, so I stuffed them full of clecos to remind me not to rivet them. That is anything but a foolproof method, of course, because the act of remove-cleco-insert-rivet is fully ingrained into my psyche at this point. Still, I thought I could manage to leave a measly three holes unmolested.

Just to help with the math, the separate page of autopilot bracket instructions called for six holes to be riveted in the case of what they call a PRECONST installation. The other option is POSTCONST; that's for the pitifully burdened people that are trying to install these things into a completed airplane. Not only do they have to drill out some very hard to get at rivets, they get to put in nine rivets for this step. I was happier to only have to deal with the six, thank you very much.



There were another three rivets after those six, but trying to determine that from the plans was a bit of a chore. I think Van's must have had Obscuro the Obfuscating Ostrich come in on Mondays to write some of these directions. Foreshadowing: it got worse. I finally figured out that the three rivets went in the flange of the bracket and the "aft intercostal." What's an intercostal? I have no idea. Ask the darn ostrich.



Here's where Obscuro really got me. See, I'm in the PRECONST clan, so I skipped ahead to Step 3, as directed, completely skipping over Step 2. Well, no, that's not right. I did my Step 2, which was to ignore the POSTCONST Step 2. Which, as it turns out, was not the right thing to do at all. Well, it was the right thing in that it's what I was told to do, but not the right thing in that one of the steps of POSTCONST Step 2 is also necessary for us PRECONST folk. Confused? Here, let me show you.



The part that I was instructed to skip but needed to do had to do with removing a rivet (one that I had just put in two days ago; I think they want me to skip this step out of embarrassment for making me remove something that I wouldn't have put in at all if they had thought to edit the directions on the prior page) in order to swing a nutplate out of the way of a screw that needs to be put in. With the nutplate still in place, that screw ain't going in, PRECONST or POSTCONST.



Of course, what with my having skipped the meatier of the Step 2s, I had no idea why this was the case. I figured I'd just have to remove the nutplate. I went back and read the real Step 2 and realized I only needed to drill out one of the rivets, so there is that. Fifty percent less rivet removal using their method. That ain't nothing.



Unfortunately, the drill bit went through the hole and nutplate as the rivet was drilled out and bent the nutplate down. To get it back where it belonged so I could rivet it back in, I had to clamp it.



I thought it might be a good idea to get the don't-rivet-here clecos out onto the other side of the rib so that I wouldn't end up building so much airplane around them that I couldn't get them out. That was also beneficial in reminding me not to rivet into those holes as I riveted all of the rest of them. Obscuro's drawing showing where rivets needed to go was obscured (or course) on the far side of the ribs and there was no "LP4-3, 12 places" (or whatever - I don't remember exactly how many it was) to tell me how many to expect - just "LP4-3 TYP." That usually means fill every hole you can find with a rivet, but doesn't necessarily countermand a "LEAVE OPEN" directive. Man, this stuff can get confusing!



So what's my beef with nutplates? Well, I thought that I was at a pretty good stopping point, but the next step was simple: put eight nutplates in the brackets that will hold one of the seat belts and rivet those brackets into the three holes that I had been obediently keeping open. How hard could that be?

Normally? Pretty easy. Especially since four of them used flush blind rivets - the easiest kind! Except this time, one of the nails broke off in the rivet puller, leaving an obnoxiously long remainder in the rivet. Obviously too long to just leave in there, but too short for the rivet puller to get a grip on.



That's never happened before!

But good things? They come in three. It was only a couple of rivets later that it happened again!



The third time it happened, I decided to remove the broken nails and call it a night. The only way I could get them out of there was to remove the tip from the rivet puller so that it could get a grip on them and pull them out. Without the tip, though, the head of the rivets extruded themselves up into the rivet puller. When that happened, they were no longer flush and had to be drilled out. When I was putting the replacement rivets in, I found that using the next smaller size tip would pull them without breaking them as the larger tip had, but the nails would jam in the puller. I had to take it apart after each rivet to get the nail out.

And that is how I came to have my absolute fill of nutplates.

I did go ahead and cleco the parts together, though.