Sunday, April 25, 2010

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 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!

1 comment:

Anonymous said...

Yes, 4 x both = eight x 2 rivets unless some are blind which presents more interesting fun for you.

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