Rolling along...

This morning I riveted yet another brace to the posts that hold the bushings that hold the pins that hold in the wings that will hopefully reliably hold my fragile skeleton aloft over central Ohio.

Oh, and I met an old lady that swallowed a fly. I won't go into why she swallowed a fly...

The directions for riveting in the braces insisted that four holes remain free of rivets. In light of my utter and complete failure to do so with a rivet hole yesterday, I've applied another layer of protection to my reminder process:



Clecos with duct tape! If that doesn't do the trick, nothing will.

Note also that I have started a new practice: I also put a few rivets in along with the clecos because they are just ever so slightly thicker than the clecos. They force the parts into the exact alignment, rather then the almost exact alignment provided by the clecos.

With the brace in place to hold the posts rigid, the only remaining thing to do in that area is to install the rollers that the wing spars will (see if you can guess.....) roll across as they are slid into the side of the fuselage.



That was all fairly routine, but the next step was anything but. I've assembled any number of bearing assemblies thus far, and it is not unusual at all to have one side of the assembly countersunk for a flush rivet. This time, though, I had to countersink both sides and do a "double flush" rivet. Sorry, no pithy comment on that will be forthcoming. It's a target rich environment and I just don't trust myself.

I had to look up what it meant and more importantly, how to do it. Basically you just squeeze the ever-luvin' stuffing out of the rivet and it will (in theory) end up being flush on both sides. The second countersunk hole is to provide room for the shop head (the one I squeeze) to expand.





I can't say that it worked all that well.



There's only so much squeezing for me to give, alas.

If push comes to shove, I'll grind them flush with the Dremel. You know how I am with the Dremel: just give me an excuse...



Next was what should have been a routine separating and marking of parts. You know what happens any time I say "should have been," don't you?

Here's the directive:



Here is the "raw" part to compare against:



Note the relative positions of the holes that I labeled '1' and '2' with the holes in the hatched are of the drawing. Looks just right, right? But you also have to consider the "THESE TWO SETS OF HOLES SLIGHTLY FARTHER APART THAN THE OTHERS" statement. Because it is so very explicit, it is the only choice for determining the correct orientation of the part. The problem was, I couldn't see any difference in the spacing, at least not definitively enough to overrule the bias introduced by the overwhelming certainty that I was correctly gauging the relative positions of holes '1' and '2' - pretty compelling evidence in my book.

I needed to consult an expert for a tiebreaker. I called in Mr. Micrometer.





According to him, holes '1' and '2' were to be ignored. I'm glad I asked!

This is all in preparation for putting together yet another bulkhead. This one will require drilling with a Uni-bit, and I keep that particular device at the hangar. It will have to wait until tomorrow.

They grow up so quickly!

And before you know it, they've left the nest!

Over the last few weeks, I've been reluctant to mow past one of the pine trees alongside my house because a momma robin has been in her nest sitting on a trio of little blue eggs. She'd tough it out and try to stare me down, but eventually her discretion would get the better of her valor and she'd flee the nest, leaving her soon-to-be brood to the mercy of what to her must have seemed an implacable and terrifying demon. I kinda feel that way about the mower myself at times, if you want to know the truth of it.

A couple of weeks ago I noticed that the eggs had been replaced by three little baby birds. Momma would still take flight as I passed by, but she'd be even more agitated than before. Two nights ago I thought to take Co-pilot Egg for a visit so she could see the little chickies that have been waking her up in the mornings with their plaintive cries of hunger.

They were gone. Flown the coop, as it were. Taken wing.

I was shocked! How had they grown so fast?

I had occasion to wonder the same thing as I was trying to move the fuselage section from the workbench to the saw horses to provide a better angle for riveting.



Ugh! When did this thing get so big???

That's a rhetorical question (you know what that means, don't you? Whoa, don't answer! That one was rhetorical too!), really. I know exactly when it got that bag. It was right after the cockpit floors had been riveted onto their underlying ribs by Co-pilot Egg and her new beau Lucas. Once they were done whitewashing Aunt Polly's fence riveting the floors down, I clecoed the whole assembly to the front of the center section.



To rivet it all together was going to be yet another mass riveting job and while I generally prefer to do those at the hangar where I can entice others into doing my bidding use the air riveter, there were two things that convinced me to stay at home and beef up my Popeye-like forearms with the manual riveter: the assembly is now too big to fit into my Subaru, and at least half of the rivets were going to be going through rib flanges - the air riveter wouldn't fit in there.


"I pulled rivets on me RV-12 wit me bare hands, ack ack ack!!"

You can see the extent of the job. Four holes per flange, with two flanges on the ribs at each end and the two in the middle. Twelve sets of four. Forty-eight rivets. And, of course, all of the ones on the top side too. That adds up to a whole lotta rivets.



When I started on this kit, I was lucky to be able to pull a dozen at a time.

I dove right in and immediately ran into a problem. As with most problems of this nature, it was going to be either a problem of my own making, or not a problem at all. Here's the region of difficulty:



The rivet marked "Easy" was exactly that. Installed without even opening the can of spinach. The other one? Couldn't even get the rivet in the hole because of the unconscionable filibuster of the rivet below it. I tried all kinds of contortions, even considering a few parliamentary tricks, but to no avail.

Then it happened!

I suffered one of those brief moments of lucidity that I have, throughout my professional life, managed to leverage into a fairly successful career. If they were more frequent and/or predictable, I could have really been somebody. Instead I muddle through my days drifting in a mental haze, just waiting for occasional flashes of inspiration to get me by. This, my friends, was one of those times.

I put the rivet in from the other side of the hole.



I expect to hear from the MENSA folks in the next couple of days.

Or not.

Here's why.

After all of the ribs were riveted in, I went on to add a couple of the parts that will serve as restraints for the critically important wing spars. It should have been easy: four rivets per, easily accessible. But...



As careful as I thought I was being by leaving clecos in the holes that were not supposed to be riveted, and providing a second layer of prophylactic in the form of Sharpie-marker X's over the holes, I had managed to accidentally prematurely rivet a couple of holes. Fortunately, if there's anything easier than putting in a blind rivet, it's drilling one out. Or two, as the case may be.

Here are the "posts" that will support the wing pins that get pushed through the wing spars to hold the wings attached to the airplane:



I wish them every possible success in their future endeavors!

The Tom Sawyer Technique

Of all of the books that I read under duress back in high school but appreciate having a dim remembrance of today, Tom Sawyer has to be in the top five. Not coincidentally, I had a part in the school play of the same name. It wasn't much of a part, mind you. I didn't have a single line (as I remember it) - my sole function as Dr. Robinson was to be murdered by Injun Joe. At least it was a nice, soft piece of Styrofoam that he hit me with; on a public school budget, there wasn't much money for good special effects. A real rock would have been cheaper.

The reason I bring up Tom Sawyer is that one of the things from the story that has stuck with me the most is the way he tricked the other kids into whitewashing the fence his Aunt Polly wanted painted. You know what's just like that?

Riveting.

As much as I'd like to include installing nutplates in my attempts to fool other people to do work for me, the person has not yet been born that is naive enough to believe that to be any fun at all.

Riveting is much easier, though, because the pneumatic rivet puller is such a cool gadget. PfwuhhhhPOOSH! PfwuhhhhPOOSH! And before you know it, the job is done.

It's sad, in a way, that the only job I can easily foist onto the unsuspecting is one I actually enjoy myself. Life's cruel ironies can be trying at times.

Tonight it was riveting the floors onto the underlying rib structures. As with most large riveting jobs, it's the payoff to a long series of mundane tasks. And, as with all large riveting jobs, it is worth the effort of hauling the parts out to the hangar to use the air riveter. Tonight was no different, and had the added bonus of a new helper: Co-pilot Egg's boyfriend Lucas. I took then out to the hangar, pulled a couple of instructional rivets myself, and turned them loose.









My only mistake was telling Co-pilot Egg that she was pulling the rivets right where my tender behind would someday be sitting. I caught her trying to leave one rivet un-pulled. Man, that would have hurt to sit one!

I had a little more time available to finish up the job, but...

Nutplates.

Amazing how quickly my helpers disappeared.

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.

In which I end with an emphatic NO!

Well, I started a new page which I shall call 21-05. There's something you need to know right up front about old 21-05: there's a lot of room for mistakes to be made on this page. All eight of the seat ribs will come into play, but they are divided into four groups of two, each group being subtly different in its mix of belt restraints and nutplates.

Here's some free advice: as each of the pairs get completed, use the Sharpie to mark which step you were on when you put them together. That's how they're going to be referred to when you have to select them in later steps.

The first strange thing I noticed was that those factory-made dimples I was so happy about? They missed a few.



Odd. As with things like this that I've noticed in the past, I'm sure there was a reason for it. I'm less than certain that I will ever know what that reason was. It's not a problem by any stretch - I'm so used to dimpling now that I do it almost robotically.

I struggled with the math again, though. Step 3 has four nutplates to be dimpled, but they then get riveted onto two seat ribs. That math flat doesn't work. I had to assume that I actually needed to do eight of these.



The riveting too has become second nature, although every now and then I run up against something like this that appears to be completely impossible:



And it appears to be impossible because, well, as much as I hate to admit it, it is. A blind rivet gets used here.



A little acronymal advice for you there on the picture. If you don't get it, google it. Although, it may be NSFW. (Google will know that one, too)

On the opposite end of the confusion spectrum, I saw this little tidbit:



Long time readers will remember how put out I was when a similar notice was NOT given when the same type of flush blind rivets were to be used on the horizontal spar box. I only found out about it before making an expensive mistake by seeing it mentioned on someone else's blog. I still wonder why (well, "if" - it's not like I've gone back and checked) Van's hasn't released a revision for that page in the empennage kit.

The parts that were to be countersunk are a pair of braces that will provide additional beefitude to the ribs that hold the mystery mixer box and the other little box that I built.



These braces were interesting because while it was the case that they would only match the holes in the rib in one direction, they would still match if you flipped them over. For a perfectly flat piece, that would make absolutely no difference whatsoever. In this case, though:



They aren't. Perfectly flat, that is. They're bent. Curved. Parabolic, as it were. Is this a problem? I don't know. It is not mentioned at all in the plans. I tossed a coin and decided that I'd install them bowed down into the ribs. It didn't seem to matter.



From the other side:



The plans specifically said to rivet on the brace; they said nothing about riveting the rib to the flanges of the mystery box. So I didn't. I marked them so I remember to keep an eye out for the step during which those rivets get installed. Just in case.



I have to apologize that I can't provide any help regarding how to keep track of the eight ribs and which goes where (or when or why, for that matter) - I puzzled my way through it and ended up with another pair of ribs holding a mystery box. In this case, the mystery box. Yes, it's the magical flaperon mixer!



I had been wondering when the autopilot servo brackets were to be installed. The autopilot kit came out after the RV-12 was in production, and I wasn't sure if the standard plans included instructions regarding when to install the brackets. The brackets and a single page of instructions came with the fuselage kit, though, so I knew it had to be done eventually. I'm keen on getting it done during the build because I've heard that while they can be installed later, it's a PITA. (You'll have to go to www.urbandictionary.com for that one. Hint: it's not bread.) In light of that, I was happy to see this:



I was less thrilled about this:



A single-word command: REMOVE.

I replied with a single word myself: NO!