19 Jan 05 - More Top Skin Stuff


Let's keep working on the top skin. Today marked something of a departure from what they tell you to do, so let's detail that as the results may be interesting. The F-688 gusset that you've got to match drill is sandwiched between two layers of metal that are already both match drilled. It seems to me that just putting the layer of metal in there and then match drilling it is a bit risky, as you could miss the bottom layer of metal's previously drilled hole. Shouldn't happen, but it could. What we're doing instead is match drilling the gusset to the top skin, and then we'll cleco and match drill that whole pile onto the other parts - we're match drilling something twice, but we know that it'll line up correctly. Knowing that we'll be getting holes that may be slightly larger than they are ideally seems a better bet than maybe getting holes that are way out of whack. We'll see how this goes.


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Gusset match drilled to the skin.
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Goofy picture for the FAA: yeah, that's me.

Clecoing things on didn't yield the fit we were hoping for (again), and it seems pretty clear that things are fluted correctly. What gives? Turns out that the top stringers were just a bit long, and they were pushing the bulkhead forward. Filed those down, clecoed it back on, and the fit is much better now.


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Yeah, this part right here, but the bulkhead's pushed forward a bit so it looks like they're not running into each other. Trust me, they are.
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Gusset clecoed to the bottom part. Everything lines up, so it looks like our technique worked just fine.

For what it's worth, we started by match drilling and everything in the center and then working our way out. Seemed to work okay so far, but since we're not done drilling it (and riveting it is a few months off), I'm not sure I can really recommend this. Your milage may vary, I guess.


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Mostly drilled. Well, the top and right side, which is what you're looking at.
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Well, that's just great. Now all the clecos smell like chocolate.

Tomorrow's the monthly TVRVBG meeting, so probably we won't get a lot done. Should be able to finish drilling this, though. Maybe we can find more clecos, too.




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