Fuel tank mystery hole

[rvbuilder2002]

I would have to do some checking on Monday to be sure, but I think teh bend angle on the baffle flanges is slightly different between the top and bottom (it's not a symmetrical airfoil).

[berck]

Any resolution? Would be helpful for the next guy who makes the same mistake (me). I just assumed the parts were symmetrical, and got lucky (50/50 chance!) on the left wing. Not so lucky on the right wing. I'd simply assumed they were symmetrical and drilled through both on the top and the bottom to preserve my match drilling, as I'd already match drilled most of it when I realized the problem. If they're not symmetrical, would be good to know that now rather than after I rivet it in

[Mike H]

It is not symmetrical. The -14 plans called out this tooling hole that identifies which flange is the top, and has a note telling you to not drill and rivet the skin in this location. Can't remember if the -10 plans called it out, but I do recall the -10 plans were slightly different and contained less deatil.

The hole in the skin would be easy to plug, or you could just add the additional fastener. Have you tried installing the baffle right side up to see if the skin to baffle rivet holes align correctly?

[berck]

What's asymmetrical about it? The flange angles? All the holes (except that center hole) line up. I haven't swapped it, but since they all line up with it in backwards, I'm sure they line up with it the other way, too. But since it's all match drilled, it seemed better to leave it backwards.

The extra hole isn't mentioned at all. I drilled it, and planned to rivet it because the directions say, "Final-Drill all tank skin to baffle flange holes to #40" and this is clearly a tank skin to baffle flange hole. The hole does not show a rivet being installed, but it doesn't make sense to just leave the hole open?

[Mike H]

The flange angles are definately slightly different. I did cleco one of mine in upside down when I initially fit it prior to match drilling despite reading the note and knowing better, the skin to baffle holes did line up. I cannot remember if the holes common to the aft flange of the ribs and baffle will line up correctly if it is installed upside down.

[berck]

So what do you do with the extra holes? Fill them when it's time for paint?

[berck]

Van's got back to me with confirmation that the flanges are indeed at different angles. I can't really see it, but I believe them. It's otherwise symmetrical, so I swapped it to the correction orientation and all the holes still line up, so I'm just going to press ahead, and not worry about the fact that all the holes were match drilled in the wrong place, since they line up.