F

fred gassit

Member
Hello everyone, I have installed all the z brackets on the wing spar and clecoed the tank baffle onto the z brackets.(RV-8)

The 7th z bracket is clecoed on and than you check through the holes that the centrelines are there. No problem on top (the baffle holes)

Looking through the spar however, the nut plate holes are misaligned by 3/32 of an inch.

Im at a loss to come up with an answer, both baffles are the same length and all the relevant dimensions between left and right wing are the same so I'm quite sure the same thing will happen with the next wing.

If I backdrill through the spar holes maintaining present alignment I will have edge distance (for AN3 bolts in a nutplate) of 7/32.

I either need a larger z section or someone to point out a very obvious error I am making because everything appears fine up to this point.

Thanks in advance.
 
The "seventh" Z I presume is the root end Z, in which case it's a Van's screw-up, but not to worry, they'll never address it!

Here's how to deal with it. Get a fresh piece of Z. (You'll need to order from Van's, and some extra can be handy making brackets and such later on. If you want to salvage the existing piece, you'll have to live with slotting the 1/8 hole that you use to cleco to the baffle.) Remark the centerlines on each flange. Slip the bracket into position and shuffle it so the baffle and spar centerlines split the difference in misalignment. The hole pattern punched in the spar is about 3/32 too far inboard of it's proper position to pick up the exact centerline. Clamp, clamp, clamp. Believe me, if you don't there's enough movement from drilling pressure to throw off final hole congruity. Match drill baffle and spar holes to the flanges.

When you're installing platenuts on the other six brackets, keep in mind this 7th bracket simply has the through holes.

Had to do it on four RV-7s (same wing as -8s).

John Siebold
 
I think that is the outboard one.

Check the prints again. I seem to recall that it is oriented the other way. -Vic
 
Thanks for the replies guys, it was the innermost z-bracket I was talking about.
Interesting that it is a drawing error, it had me completely at a loss.

I spoke to Vans as well and they weren't worried about it, I think if they had a choice they preferred the tank to baffle rivets centred and the bolt holes off centre but said it's fine either way so I've gone ahead and done it.(along with some of the ugliest riveting I'd put my name to getting at the nutplates...)

Vans support's first choice is as you suggested John which is what I'll do on the next wing.

Thanks again
 
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