The Shark

Two things about sharks: they have to keep moving, and they have cool gills. How cool? Cool enough that designers have been plagiarizing them for years and years.











They sure look good, don't they? Well, as it turns out they are quite functional too, and I don't mean just for sharks. Although if you ever asked a shark, I suspect he'd tell you that no one really needs them more than he does. The shark has a weakness, though: he has to keep moving to breath. And he has to keep breathing to grow. And he has to keep growing to get big enough to sink a boat out from under that twerp Richard Dreyfuss. Win-win, I figure.

Yes, you're right. This is another one of those long-winded, stretched-to-breaking metaphors. Rather than drag it out any further, here's the deal. I had to move the fuselage to the hangar. It was getting bigger and bigger and was in danger of being beached stuck in the basement. As it was, it was already too big to move in my Subaru. I had to enlist the aid of a slightly larger SUV.

Too slightly, as it turned out. It wouldn't fit in there either.

It had to ride on top.



What's that got to do with the aestheticism and functionality of shark gills, you ask? Is having to move the thing really a thick enough plank to support the weight of that overwrought simile?

Nope.

I have to stop here and share something. This is blasphemous and you may want to avert your eyes. As unpleasant as it is to say, I feel that my inherent honesty compels, neigh, requires that I confess that there are two parts of the RV-12 that I find to be absolutely hideously ugly: the wing tips and the shark gills.

The wing tips have unsightly gaps where the openings between the tabs on the flanges show through, but they are designed for function over beauty. They are (ostensibly) easier to build than messing around with fiberglass, and they have nice hand holds built into them to aid in carrying the wings around when they aren't attached to the rest of the plane. Ugly, but eminently functional.

The shark gills address another building issue. Where the front of the plane meets the back of the plane, there's one of those uncomfortable situations like the east side of a transcontinental railroad being a few feet north of the west side when they first meet in the center. With the RV-12, there's a section that would require a compound curved piece of metal. Rather than create an expensive and hard to produce piece, the designer(s) opted for some curved pieces that would attach together and work their way around the tough spot. I call them the shark gills.

For me, the shark gills have been of those iconic parts where I had seen them on a completed plane and thought "I'll rivet those in myself some day." It was right after thinking "Man, are those ever ugly!"

Today was that day.

I had to finish up a little bulkhead riveting first. Once I realized that I'd be moving to the hangar (Home of the Big Boy Power Air Riveter!) I went on a bit of a riveting strike. Why tear out my tendons using the manual rivet puller when I was going to have the power of compressed air to do my bidding? That said, there were rivets inside of flanges that I'd have to deal with. I've been doing those manually. I figured I'd burn that bridge when I got to it. For now, it was full steam ahead on the bulkhead.



Have I mentioned how easily I get spoiled by power tools? I'll spend an order of magnitude more time and effort trying to force a power tool to do the job than it would have taken to just knuckle down and do it manually. Which is how I ended up pulling the inside flange rivets with the air puller.



Oddly enough, it worked pretty well. Right up until it didn't, anyway.



Just as I did with the manual puller, I used the little metal wedge to get the rivet puller in good contact with the rivet. Unlike with the manual puller, if the little wedge gets a little crooked while I'm pulling, it gets, well, wedged pretty tightly in a bad place. It was quite a chore to get that thing back out of there.

The next step was to put in a slew of plastic bushings. They just snap right into the holes and are very simple to install, but I found that I had to lay the plans on top of the fuselage to figure out exactly where each was to go.



And, at long last, the shark gills!

First, cleco them into place.



It goes something like this:

(You might have to press the play button for the full effect)


And ends like this:



The longerons are the next iconic step. And I hear they are no fun at all.

A movable part!

I installed a movable part tonight, and what's more it was a part of the actual control system.

Most of my nights in the shop start out with something mundane or difficult, or both. That's because when I was faced with something of that nature the night before, I decided that it would be a good time to stop. Tonight is was nutplates. Again. They weren't too bad, though, since they ran along the edges of the floor boards I had riveted in last night and were therefore easily accessible. Well, mostly. There were a couple that required reaching up behind the bulkhead to get into position.



There were five to do on each side. That's a total of ten for anyone keeping score at home. There were three of the type of soft blind rivets that have been giving me fits on each side, but I was able to pull all six without having a single one break off way up inside the rivet puller as has been happening recently. The trick seems to be to squeeze just a little, release the squeezer and reposition it at the bottom of the nail, repeat, repeat, repeat. It's when I try to pull the nail in one big squeeze that I have the problem with them breaking off up inside the puller.

Here the are, all in a row:



Finally it was time to thread the control column through the lightening holes and into position. Well, first I had to final drill all of the holes in the tabs that the mounting bolts pass through to remove the powder coat, but that was more or less easy. The 'less' was because there were holes that were too tight up against the control column for the drill to fit easily, but I managed.

Speaking of tight fits, it took quite a bit of jiggling and wiggling and wrangling and tangling to get the column through all of the holes. It was almost like a puzzle - turn it this way to get through this hole, and that way to get through the next one...

It took a lot longer than you would think.



Here it is, all snug in position:



There are just a couple of small bolts that hold it into place, but each bolt has a collection of five washers that act as spacers. The order goes bolt head - flange - washer - washer - bearing - washer - washer - flange - washer - lock nut.

Four out of the five washers are a pain to get into place. The plans suggested using a tab of tape on the washers, which actually worked pretty well once I figured out what they meant.



The first bolt took 15 or 20 minutes (and a half dozen dropped washers) to get in. The second went a little faster, but not much. Both were torqued into place.



Unfortunately, the first bolt was just for practice. As I was making my last quality assurance check, I realized that I had made a mistake.



I installed that one bolt head - washer - flange instead of bolt head - flange - etc.

The one easy washer was on the wrong side of the arrangement. The hole thing had to be removed and done over.

That kind of thing seems to be getting to be a habit.

Old Yeller pulls through!

Making a mistake late in the evening when I'm tired from a long day of work has pretty much the same effect as eating a large pepperoni and coffee bean pizza just before bed: I sleep, but not the restful, rejuvenating kind. It's a shallow sleep, easily disturbed by the puppy rolling over in his crate or the cat losing what must have been three separate meals on the bedroom carpet. It's a sleep also punctuated by bizarre and disturbing dreams that magnify and amplify the stresses of the day into what seem to be insurmountable obstacles. In the early dawn's light, though, things return to their normal scope. Things like doublers on the wrong side of the bulkhead no longer carry the import that they did in the middle of the night; they are seen for what they are: an hour of backtracking before tackling the job again.

Which I did tonight. Job number one was to craft a tool that would aid in removing the LP4-3 rivets. Those still have a piece of the "nail" in them and that can cause problems when trying to drill them out. The bit senses the harder metal of the bail and, much like a good running back, just goes around it. That's not a good thing since the "around" is comprised of important material that we don't want to cut away. To punch the nail out, I borrowed an idea from a $20 tool I saw recently. I ground down the tip of a $5 Harbor Freight center punch to that it would fit into the center hole of the rivet. Just a punch or two was enough to punch out the nail.



It pops them out with enough force that I could hear some of them bouncing against the far basement wall. I'm going to be finding those for years! Once the nail is out, the drill bit walks right down the hole in the rivet and pops the head off in no time at all. Conveniently, the rivet heads roll up the bit for later disposal.



The solid rivets were much more difficult, although I did find that my new rivet removing punch worked just as well at pushing the body and shop head of the solid rivets out of the hole once the top of the rivet had been drilled off.

Everything was then reassembled and we were back to where we started, except with the doublers on the other side of the bulkhead.



I had enough time left to take the next step. That was the riveting in place a couple of the floors. These particular floors will be under the seat cushions when the plane is done. They have a pretty sharp bend on one of the flanges, and unfortunately it requires dimpling for a nutplate and an eventual rivet. That was a bit tricky and I eventually had to resign myself to the fact that the flange was going to get a wee bit bent out of shape from forcing the rivet squeezer (equipped with dimple dies) in there to get the job done.



The floors were easy to rivet on, although I did have a situation where one of the LP3-4 rivets pulled halfway out of the hole on the first squeeze and had to be drilled out. Having perfected the job of drilling out blind rivets only an hour before, I didn't even breath a sigh. Took it in stride, did I.



Tomorrow is a big day! The first of the control pieces goes in. It's the column that ties the two control sticks together. This is when it will really start to feel like an airplane rather than a ghastly ugly modern art sculpture.