Category: Fuel Tanks

Ok, so I’ve been anxious about starting the next step for the fuel tank but finally decided the time is now.  It’s time to start to apply proseal and rivet the tank!

Well, let’s back up just a little bit and talk about the prep.  Standard stuff, deburr all the parts, and get them appropriately dimpled.  I went with the Cleaveland Tank skin dies for the skins, and the sub-structure dimple dies for all the stiffeners and such.  I also did all the necessary countersinks and hopefully made the right call to countersink the tank attach bracket that wasn’t specifically called out.  Guess the expectation is that the builder needs to start figuring our more stuff on their own.

The other thing I was researching and deciding upon was how I was going to apply the proseal and what system to rivet the parts.  Specifically I decided to buy a few of the 3.5 oz tubes of proseal and to use the pneumatic dispenser to hopefully keep the mess to a minmum.  I also decided to follow the suggestion here on how to complete the assembly.  Basically I will apply a layer of proseal and then cleco the parts together.  I then shape and clean up the edges of the part and allow the proseal to set-up.  I then come back and remove the clecos one by one and wet-rivet the parts together to complete the process.

The down-side to this process with the pre-measured tubes is that this can be wasteful.  I was able to do all the attachments to the ribs, the stiffeners, and the fuel tank cap with 1 tube.  Then I riveted all the parts on the ribs and riveted all the parts on the top of the skins and ended up wasting about half a tube. (Mostly as I ran out of time and had to call it a night).  I have the Qt container of proseal on order and plan on mixing up some smaller batches when I need to rivet.

Also not sure how visible it is in the time lapse, but I didn’t do this with the fuel gauge nutplates.  Ugh, I can start to see why this recommended method is so much nicer.

Below are some photos, as well as a time lapse.

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Next project is to start the fuel tanks.  I started by pulling all the parts and making the tank stiffeners.  Only issue is that the tank stiffeners are longer than the throat on my band-saw, so I ended up using my snips to rough cut them to size.  Then used the bandsaw to cut the angle on the ends, followed by finish sanding on the belt-sander and deburring on the bench grinder.  Then I trimmed, sanded and deburred the Z tank attach brackets.  I ended up trimming these parts for both tanks at the same time.

Then it was on to straightening the ribs for both tanks as well as getting them deburred.  Then it was on to measuring, cutting and deburring the J-channel for both tanks.

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So I’m making progress on building the fuel tank (forgot how enjoyable it was to make progress!) and just about at the point where I’m ready to fully disassemble / deburr / dimple.  Per my previous post, I was able to adjust the skins for the locking fuel caps and now I’m at the point where I’m trying to figure out how to fabricate a fuel return line.

So I’m not an engineer or true engine monkey, however in the research I have been doing, if I decide to go with one of the EFII solutions (either FlyEFII or SDS), then I’ll also need to have a way to return fuel to the aircraft tank.  Basically their designs will return any excess fuel back to the tank.  This requires not only a fuel return port / line, but also a duplex fuel selector valve so when you pull fuel from the right tank, it returns excess fuel to the right tank.  Plenty of discussion on VAF for those that want to know more and I’ll possibly get into it more later in the build.  For now however I would rather add the port before the tank is sealed vs trying to do it as an afterthought later.

Currently my thought is to add a second VA-141 fuel flange to the inboard aft rib.  It’s not obvious but based on experiences from other via VAF, you don’t want to do this in the area shaded in RED.  My plan is to add it to one of the areas in greed below.[inpost_fancy thumb_width=”200″ thumb_height=”200″ post_id=”695″ thumb_margin_left=”0″ thumb_margin_bottom=”0″ thumb_border_radius=”2″ thumb_shadow=”0 1px 4px rgba(0, 0, 0, 0.2)” id=”” random=”0″ group=”0″ border=”” show_in_popup=”0″ album_cover=”” album_cover_width=”200″ album_cover_height=”200″ popup_width=”800″ popup_max_height=”600″ popup_title=”Gallery” type=”fancy” sc_id=”sc1539183671197″]

I have some AN fittings as well as the VA-141 flanges on order to do some test fittings to make sure this will work as well as a message on the VAF to make sure I’m not missing anything.  Hopefully everything arrives by Friday so I can possibly start the “dreaded” proseal process this weekend?  Currently have 2 tubes of proseal on order that also hopefully arrives. I think i’m going to stick with the pre-measured stuff that you mix in the tube based on some posts about proseal de-curing currently being discussed?!?!

Update:  Looks like using a second VA-141 fuel flange from VANS, as well as a AN816-6-6D Nipple should do the trick.  Honestly this appears to be similar to the Bung that EFII is selling, just internally mounted vs externally mounted?

So I decided that my next challenge is going to be the fuel tanks.  A few months ago I began to do some searches on different fuel caps as I was thinking I wanted to upgrade to locking fuel caps.  I got a set of the standard caps in my wing kit, but began to think that I wanted to purchase locking caps as an upgrade.  After giving a call to Vans to verify what I needed to purchase I learned that all kits in the future will be upgraded to the locking caps by default. (Don’t quote me on this but this is the impression I got as they needed to look up my kit number to see what size fuel caps they sent me.)

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