Friday, February 4, 2011

Ha ha ha, just kidding!

Hey, I've got nothing against a good joke. I don't even mind being the subject of the joke now and then, as long as the word 'scrawny' doesn't enter into. Practical jokes? Love 'em. In fact, I just yesterday had a little fun with a Green Bay Packers fan at work. A few minutes with Google, a color printer, and a little tape and before he knew what had hit him people were questioning his treasonous leap to the other side!

It was all in good fun; no hard feelings, etc., etc.

But sometimes these things can just go too far. Take last night, for example. There I was, out in the 25 degree hangar trying to get a part to fit on the wing tip. It was one of those cases where the drawing in the plans doesn't do much more than show you which end of the airplane the part goes on. Vincent Van Gogh had a better handle on realism than whoever penned this particular drawing. That's usually not a huge problem; each part is labeled with a part number, and as we've seen over and over again, if the part won't fit and you're sure you're using the correct part, you're just doing it wrong.

Or, so I kept telling myself, over and over and over. But no matter how I tried to position the part, it simply would not fit into place. I couldn't figure out what I was doing wrong. There was a clear and obvious curvature to the part that simply had to match the aerodynamic, Bernoulli-driven curvature of the wing, but when I tried to position it that way, it seemed completely backwards. I double-, triple-, quadruple-checked the part number. It definitely had a '-L' on it, and I was definitely working on the left wing.

After an embarrassingly long and futile effort, an inspiration struck me! Would the part marked with a '-R' wing fit any better?

Yes. Yes it did. It fit perfectly, in fact.

I have to confess: I was not amused. Sure, I appreciate the humor and I could have laughed along, but it had been another of those days that seem to be coming more and more frequently... I wasn't in the proper mood for it.

It all looked better in the morning after a good rest. All was forgiven and I had a good chuckle over how gullible I had been to fall for such an obvious joke. And as they say, forewarned is forearmed. I'd now know to be on the lookout for more shenanigans like this.

This afternoon I went back to the hangar to install the forward part of the two-part tip rib that I had failed to complete after my fit of pique. This one was going to be a little trickier because it needed to be fluted to fit both the Bernoulli curvature and the rounding of the wingtip.

Vigilant for another left vs. right prank, I clecoed the rib into place. At first I thought they were having me on again, but then I realized that it was the correct part after all, it just needed a lot more fluting that I had thought it would.

I wasn't quite sure about the proper layering at first, but this way seemed to fit the best. Remember, we're working with a pretty uninformative drawing on these steps. As I look at it now, though, it looks wrong. It fits nicely into a gap between the tab on the front of the back rib and the wing, but it might have ended up looking more correct if I had forced that tab to fit underneath the back part of the front rib. Oh well, I'm not drilling it all back out again for that! I'll see how it looks when I get to this step on the right wing.

I figured the best way to approach the fluting was to just work my way down the length of the rib. I marked a line at the first spot where it looked like fluting would make a difference.

Then it was just a matter of adding some flutes, putting the part back in place, making another mark, and adding more flutes. Rinse, repeat as needed.

As they say in the orchestra, ViolĂ !

Things were moving right along until it came to the next step, wherein I will close out the wing tip at the bottom. The part that closes the wing tip is shaped like something that they would show as an example in a catalog for expensive french curves, and it requires a bit of bending on the flanges in the same way the tail cone flanges needed to be bent when joining the cone to the rest of the fuselage. If I hadn't already had that experience, I might have fallen for this joke too:

Fortunately I now know they're pulling our legs with the 1 degree increments in the drawings. Getting within 10 degrees on any of those bends will be close enough to allow for any small adjustments needed when installing the part. I had a good laugh at the attempted joke, then quit for the day. I wasn't put out over the attempt to play me for a fool again, mind you. It's just that I want to flip the wing over before trying to get that part in there and I can't do that alone.

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