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Fuel Tank Assembly

msstahl

Active Member
I'm starting work on the fuel tank assembly and the first steps are working with the Z brackets. The plans seem to be lagging the parts as all the holes are pre-punched/drilled which leads me to my question.

Is it necessary to bolt the z brackets to the spar, cleco the rear baffle to the Z brackets and attach the tank skin to check for alignment? With the accuracy of the pre-punched components this really doesn't seem necessary so I'm hoping others can validate my thoughts or provide the reason for the work.

I'm curious what others have done here before I start.
 
I think there are threads and google info called the “Dan Checkoway method” even though he gives the credit to someone else.. I plan to follow what they did. Using the rear baffle as a guide to lining everything up.
 
I created 4 templates that match the four corners of the wing tank skin and cleco the templates with the fuel-tank baffle to the spar flange. The template holes are matched drilled to the tank skin so the holes that line up with the skin and the baffles are all matched. This will keep the baffle in alignment as you drill the pass the baffle into the z-brackets.

But the pictures below should show how the templates are used.
 

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I think there are threads and google info called the “Dan Checkoway method” even though he gives the credit to someone else.. I plan to follow what they did. Using the rear baffle as a guide to lining everything up.

What he ^ said. It works.
 
The pre drilled Z brackets are very new, so you’re probably one of the first to get to this point.

I have the same pre drilled brackets, my plan is to check for alinement as per the plans. It’s probably not necessary as you say, but it’s a mornings work, and I would rather find out it wasn’t necessary than discover it was further down the line.

Did you get the email from Jessica with the new plans?
 
Tanks

I fallowed the directions and watched the Vans video on the tanks , so many opportunities to make a mistake on the tanks , it’s a critical step with the rear baffle alignment, if I did it again I would not use the vans method but fallow the many tips they provide . My tanks fit perfect but I had a few leaks to contend with that was puzzling with the amount of proseal I used . Good luck
 
Ok - sounds like there has been an update made to recent kits as Jonnyb has eluded to. The main difference being that the Z brackets are already final drilled for the bulkhead attach rivets, the plate nut holes are slightly undersized and the bolt holes final sizes. I will have to run a reamer through the wing spar to open the bolt holes up slightly. But all in all so far everything is lining up nicely.

@ Jonnyb - I have not received an E-mail with updated plans from Vans so I’ll make a phone call today!
 
Dare I say that pre-drilled Z brackets might have been a step backward for the kit. With the undrilled versions, the builder had the option to bias the bracket slightly (vice putting the holes on the flange centerlines) such that the rivet holes would be slightly closer the Z bracket web, and the bolt holes for the spar would be slightly further from the web. All still had appropriate edge distance but it provided plenty of clearance to put a socket on the head of the AN-3 bolts that holes the Z brackets to the spar.
 
Dare I say that pre-drilled Z brackets might have been a step backward for the kit. With the undrilled versions, the builder had the option to bias the bracket slightly (vice putting the holes on the flange centerlines) such that the rivet holes would be slightly closer the Z bracket web, and the bolt holes for the spar would be slightly further from the web. All still had appropriate edge distance but it provided plenty of clearance to put a socket on the head of the AN-3 bolts that holes the Z brackets to the spar.

Correct me if I’m wrong, but don’t the bolt heads go on the rear face spar side, into the z brackets? So there isn’t any clearance problems with the socket because the bolts come from the spar side into the z, into nutplates? What’s the purpose of offsetting the brackets?
 
Correct me if I’m wrong, but don’t the bolt heads go on the rear face spar side, into the z brackets? So there isn’t any clearance problems with the socket because the bolts come from the spar side into the z, into nutplates? What’s the purpose of offsetting the brackets?

That's true. This is probably only significant then on the inboard most z bracket where the bolt head is adjacent to the Z bracket web.
 
As alluded to by others, there has been an update to the RV-7/8 fuel tank design that allows for providing predrilled z-brackets for the fuel tanks.

At the time of the change-over in part production, the updates to the plans were not yet completed but since the change in actual build process is rather minor (the updated parts basically just pre-complete some steps for the builder) the decision was made to start supplying them in the kits ahead of releasing the updated plans.

Builders that have the new parts should just skip the steps in the manual related to marking and drilling the z-brackets for the bolts. Then install the nutplates, mount the z-brackets to the spar web with the specified bolts, and cleco the baffle and ribs in place.
From that point on the build sequence should be the same as described in the manual.
 
Scott - thanks for the explanation of the parts and plans difference. Seeing what the legacy kits required I think this was a nice kit upgrade!
 
Order these to replace my old ones

Can I just order these new ones and put my hours to use on some other task? I have a Slow Build Circa 2008 kit.
 
TANK ATTACH BRACKET
T-712
$2.25

Will the ones that show up in the webstore be the old plain ones or the new and improved?

I do not need them yet, but for $2.25 I think its a good conversion on $/time
 
The part numbers for the new ones are:
2x T-00712A-2
10x T-00712B-2

The numbers required are on the left.
 
Just completed the pre-assembly of all the components, the new Z brackets are flawless. Vans even offset the inboard attach holes for socket clearance!
 

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6 Bucks

Just heard back from Vans, $6 each. Not bad at all. Put them on order. This will save me a couple hours of marking, drilling, etc. I will put my old ones up for adoption for the price of postage.
 
Tech Follow up

Vans Tech Support says these new brackets with CNC machined holes work on current production -1 Wing kits.
 
Short 2

There are indeed 7 brackets. The part number for quantity of 2 are the ones nearest the wing root that get the nut plates on the spar. Needless to say its 12 + 2 that you need.

They matched flawlessly and are much better than what I could have done. Definitely a time saver. They are $6 each.
 
Fuel Tank Z Brackets for the R7

The part numbers for the new ones are:
2x T-00712A-2
10x T-00712B-2

The numbers required are on the left.

Resurrecting an old thread. I am needing to order a full set of Z brackets for a legacy kit. However, there are 7 brackets per tank so the numbers listed above are not correct for the RV7. There are 2 brackets (assuming the same on the outboard / inboard of the tank and 5 in the middle). Am I therefore correct - for each tank - I need (2x) 712A-2 and (5x) 712B-2.

Thanks in advance for any guidance.
 
Drawing 16A applies to the 7 and the 8. Those are correct parts, yes there are 7. I ordered 10 and 2 but then realized I needed 2 more once I started putting it together. You need 12 of the B type and 2 A type
 
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Drawing 16A applies to the 7 and the 8. Those are correct parts, yes there are 7. I ordered 10 and 2 but then realized I needed 2 more once I started putting it together. You need 12 of the B type and 2 A type



In all the build photos and 16A drawing - the inboard / outboard bracket are positioned the same way, with all internal z brackets facing the other.

Which end of the tank is the A type positioned?

And is the B type simply flipped for the other end?
 
The A type is the inboard bracket at the wing root. That bracket is a pass through to the plate nuts attached on the main spar. The B types all have plate nuts riveted to the bracket. They come already set up for plate nut rivet holes. Yes the outboard bracket is B that’s flipped
 
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