Thursday, November 26, 2009

My Blue Vinyl Epihany

I really wanted to get the horizontal stab skins riveted on today for a couple of reasons:

1. It's too big for me to move to the hangar in any vehicle I own, but my sister and brother-in-law are visiting with their gigantic SUV. Actually, it's so big that you could drop the 'S' and just call it a utility vehicle.

2. The CEO is coming to visit and this is the biggest chuck of airplane yet; it would be nice to have it in a presentable form.

Counter arguments were limited to one: I hate pulling the blue coating off of the large pieces. The coating material has no "grain," by which I mean that there is no direction in which it will easily tear. That means you can't just tear off strips of it. It all wants to come off in one big piece and that makes it hard to pull off of large sheets.

I decided to compromise. One of the evangelical arguments in the community is over the question of removing all of the blue stuff at once or leaving as much on the metal as possible to protect it. I think this is similar to what you see in NASCAR when the cars are behind the pace car zig zagging back and forth on the track. If you ask the first guy why he's doing it, he'll say that it clears built up rubber from the tires. If you ask the second guy, he'll say he's trying to get heat in the tires. If you ask the third guy, he'll tell you that he's doing it because the two guys in front of him are doing it. I decided to give it a try for reason number three.

The areas that need to be cleared are the lines of rivet holes and the edges. Cut Lines are made in the plastic by using a soldering iron to cut through the material. This is supposedly safe for the metal, but I have my doubts. It doesn't take long, although the smell can be somewhat nasty. Once you've done it, though, the lines of material peel right off, easy-peasy:

Here's the epiphany part: I could also cut lines to make the plastic on the inside of the skins easier to remove! I did, and it did! Cutting it into a few big rectangles made it much easier and faster to get that stuff off of the skins.

That done, I soon found out why we had put masking tape over a couple of places in the hange; both the left and the right side hinges get temporarily clecoed onto the right stab skin to have some holes match drilled:

For once I didn't stop to try to figure out why Van's had us do it this way. Schedule to keep, you know: VIP visit in the offing.

The skin halves are then to be clecoed into place. I wriggled the skeleton around in the fold of the skin to try to work the tips of the front ribs into place. Just like they did with the vertical stab, they often found it easier to just bend to the side rather than snug themselves up into the leading edge fold. A little poking and prodding get them more or less into position:

The bottom of the skin gets clecoed first so I had to roll the stab over. As you are positioning the skins, Van's suggests that you make sure that the rear flange of the upper skin overlaps the rear flange of the lower skin. It was easy to see what they meant by that sentence of near gibberish because the skins pretty much wanted to do that anyway:

Half way done and it's half skeleton, half horizontal stab assembly:

My brother-in-law would be going over to the hangar for a riveting session so I gathered up tools and supplies to be ready. As I was grabbing handfuls of rivets to take along, I remembered that measuring out rivets is like making spaghetti: you never know if you are making too much or not enough. I loaded up what I thought was plenty of rivets, then threw in another two handfuls for good measure.

I still didn't bring enough. We were about fifty short. Still, it's good enough to show:


Torsten said...

Dave, did you notice that you turned both inner forward ribs opposite to what the plans indicated? I was just look at the next steps to do and I thought that it looked odd that Van's wanted the flange showing on the inside as the skin is cut out in this area and you'll see the shop end of the LP4-3 rivets. Did you make a decision here or did it just happen by accident?

DaveG said...

I'll have to go back and take a look at that.

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