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Root tank rib screw-up

Draker

Well Known Member
:mad: Well, it was bound to happen. My first major mistake on the RV-7 build! Total carelessness. I was drilling the holes for a fuel return line into my right tank, confused up from down and drilled the hole through the root rib way too low. This was meant to be a straight shot through the upper portion of the ribs, directly below the vent line.

IMG_0049-M.jpg


Weighing my options:

1. Re-order T-703 end rib, T-407 stiffener ring, and 12 nut plates, and re-do the whole part. Concerns: The tank skin is already drilled and dimpled. How will I match-drill to the skin correctly?

2. Rivet a .025 plate over the hole and pro-seal it real good? Concerned this is a high-probability source of leaks.

3. Plug it with some kind of bulkhead fitting?

4. Use the hole as-is. Make two bends in the 3/8" fuel return line so that it can continue to the end bay. This is almost certainly not viable: The line will interfere with the flop tube's operation.

Any other suggestions? I'll give Van's a call tomorrow and see what they have to say. Boy do I feel like an idiot right about now.
 
Not the first

Been there done that. I fixed mine using method 2 with two - 3 rivets holding it on and pro seal. Not concerned with it leaking at all.
 
Screwed up my root rib yesterday too by drilling the vent line fitting oversized. Fabbed up a big washer to sandwich over the hole.. vans getting 2 root rib calls today-

Question- what's the extra hole above the doubler and the 2 #30 holes toward the nose for?
 
I haven't gotten to the point of needing to work with pro-seal yet but is it strong enough that you don't need to rivet the patch? The reason why I ask is putting in rivets just means you've put more holes that could eventually leak.
 
Cut yourself a patch , scuff, and proseal it in from the inside side. IT will be the best sealed join on the tank.
 
I haven't gotten to the point of needing to work with pro-seal yet but is it strong enough that you don't need to rivet the patch? The reason why I ask is putting in rivets just means you've put more holes that could eventually leak.

I think rivetless is asking for trouble. If it did start to leak it would be a heck of a job to fix. Use rivets, you can seal the tails and you won't have any issues.

Alex
 
Thanks, everyone. Looks like cover and seal is the consensus here so far. E-mail sent off to Van's for their view.

Question- what's the extra hole above the doubler and the 2 #30 holes toward the nose for?

Hole above the doubler is for the BNC connector for capacitive fuel level senders.

#30 holes towards the nose are to hold an anti-rotation bracket for the flop tube.
 
#30 holes towards the nose are to hold an anti-rotation bracket for the flop tube.

Sorry for thread drift- Say a little more about this- I saw the Vans SB, states that not applicable for flop tube. I looked at the anti rotation brackets that came with my kit, they're too large for the flop tube. Wondering if you have pics of your design?

For maintenance down the road, I figured it would be easier to pull the flop tube assembly off of the rib (with the angled fitting), rather than try to change the tube, torque, and safety wire through the access hole with the fitting in place. Adding the anti-rotation bracket would require drilling out those rivets and pulling the bracket too-

But I've also read that folks have broken the proseal and twisted the flop tube when torquing the fuel line fitting on final assembly, so I don't know what a good approach is-
 
Sorry for thread drift- Say a little more about this- I saw the Vans SB, states that not applicable for flop tube. I looked at the anti rotation brackets that came with my kit, they're too large for the flop tube. Wondering if you have pics of your design?

Sure. I modified the bracket that came from Van's so that the fitting on the flop tube slides in:

IMG_0045-M.jpg


Don't have a picture yet of it resting in the bracket. Motivation for this is concern about breaking the pro-seal when attaching the fuel line fitting later.
 
Just to close the loop on this one, the mothership agrees with you guys. Cover, pro-seal and build on. Thanks!
 
Sorry for thread drift- Say a little more about this- I saw the Vans SB, states that not applicable for flop tube. I looked at the anti rotation brackets that came with my kit, they're too large for the flop tube. Wondering if you have pics of your design?

For maintenance down the road, I figured it would be easier to pull the flop tube assembly off of the rib (with the angled fitting), rather than try to change the tube, torque, and safety wire through the access hole with the fitting in place. Adding the anti-rotation bracket would require drilling out those rivets and pulling the bracket too-

But I've also read that folks have broken the proseal and twisted the flop tube when torquing the fuel line fitting on final assembly, so I don't know what a good approach is-

Unless you have inverted oil, *and* you intend to fly inverted for extended periods (longer than 10-15 seconds; tell me you've done it and enjoy it....), the best approach is to plug that hole and use a standard pickup. :)

Lots of good reasons, listed in multiple threads here and elsewhere.
 
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