Section 18 Fuel Tank Repair

RV14 Build September & October   

Fuel Tank

Just to recap, I dropped the wing and damaged the fuel tank and is caused a leak.

Luckily for me the tank was just repaired and the repair patch was right above this, so i drilled it out so i could remove sealant on the inside to reseal. This allowed me to inspect for damage as well and I found what looks like 2 tears in the metal down in that same corner.

I decided I am going to replace the part and possible the aft inboard tank rib as well. First things first, time to drill out the parts, CARFEULLY so I dont mess up the skin.

After drilling out the parts and getting a much better look at the support bracket It doesn't look town afterall and that was surface scratching possible from the plastic scraper I used to dig out the sealant. The skin in the corner where that rivet I drilled out was however was cracked in the dimple so I'm going to drill that up a size and put in an oops rivet.

Primed the new brace, only on the side outside of the tank.

New brace is riveting pro-sealed in and about to get riveted. I didn't need to use the oops rivets after all. But now I have them for the future if needed.

Made sure to tighten the vent line and added pro-seal around the fitting just to make sure incase the rotation loosened the old seal.

I forgot to get sealant between the nose rib and the new brace so I loaded the seam on the inside and outside of the tank to compensate.

Adding sealant to every possible place it could leak.

Sealant is done, just need to cure so I can test it.

Looks like I FINALLY have leak free tank again.

Installing the tank back into the wing. This time I'm not going to worry about the screws on the top of the wing until the wings come out of the cradle for install.

Reinstalled the torque tube and aileron pushrods.

Other end of the aileron push rod.

Fuel Tank Repair 15.0 Hours

Section 18 Fuel Tanks

 

RV14 Build October

Fuel Tanks

To recap. My left wing fuel tanks was leaking when I tested it. I determined it was leaking from between the skin of the Aft inboard tank rib and the VA-141 fuel flange.

Testing the tank.

Leaking.

After talking with Vans they had me ship it back to them and they performed the repair. I received the tank back relatively quickly and tested it again just to be sure.

Matt made a shipping crate out of the crate the wing parts came in, nice to recycle!

The repair patch Van's had to cut and install into the tank.

Not a great picture, but I endescoped the vA-141 flange to see the repair and it looks like they added more sealant around it.

The tank tested well and Liz and I went to install it into the wing. Before I did I was reading in the plans and noticed the wing walk gap is dimpled but the holes in the tank attach bracket aren't. I spoke with Vans and they are supposed to be countersunk , but its not in the plans at all.

Quick countersinking while testing the tank.

There is a lot of screws and torquing the AN3 bolts takes a while, especially when you don't set the torque wrench correctly and strip 2 of the AN3 bolts. But we did it and finally got a working tank installed and reinstalled the push rod.

I got smart this time and installed the torque tube while installing the tank. It is WAY easier this way. I can move the torque tube up and down enough if I take out 1 set of bolts to install any washers that I might need.

This is where things took a nasty turn. I was using a ratchet strap to hold 1 end of the wing in the air while removing the work bench so we could put the wing back into the cradle and the ratchet strap unhooked itself and the wing dropped about 4 feet. The newly repaired and installed tank took most of the impact with the lower arm of the tank attach bracket assembly absorbing most of it.

Obviously my hart dropped with the wing and part of my soul died it felt like. But we removed the tank to inspect it and the wing. Thankfully the tank took everything and the wing looks undamaged. I was able to bend the flange back into alignment where the wing walk skin matched up.

There was 1 rivet in the corner that I was worried about so I drilled it out and re did it. I also added some preseal under the flange before riveting and then sealed the whole area.

After the proseal dried I tested again.......and it leaks. When the flange bend it separated the seal between itself and the skin.

For more on this saga look for the fuel tank repair post.

Fuel Tank 8.5 Hours

Section 18 Fuel Tanks

RV14 Build July and August

Fuel Tanks

I decided I may want to install ER tanks in the future so I am putting "Fuel Bung" kits from Hotel Whiskey in the tanks now so that if I do get ER tanks in the future the infrastructure will be installed already.

I struggled more than I should have in drawing out the rivet holes on the bung kit, thanks to Matt for recommending the protractor.

We used a flexible hose connected to the shop vac, and my iphone endoscope to get it in the correct location while we drilled.
Close up of the set up

View from the endoscope.

Final drilled and marked to install in the correct location.

Next I went on to work on the fuel float sensor. Checking the sensor with the Ohms meter.

Then I bent of the float wire. I broke 1 so this picture below is me trying to fabricate one from a steel rod that I bought. The rod was too soft so I ended up buying a new sensor since I couldn't find the part.

Simply screw the float sensor in and check the float.

I used the endoscope again to see how the float sits in the tank. Lots of tweaking to get the float to the correct orientation.

Against the top skin "Full" position.

Against the bottom skin "Empty" position.

Backed out view of the empty posistion.

Now that the fuel senders are in time to pressure test. First tank I had trouble right away with this plug. I tried 3 different thread sealants and could not get it to test well. After looking at it closer it would appear that the leak is coming from between the skin on the tank and the flange not the threads.

I used my endoscope to see inside and it does look a little light on sealant on the one side.

This is the plug location in question, I can't find a place that it ever gets used so I have no idea why Vans put it in?

Left the other tank overnight and still holding strong.

Used soapy water to check for leaks.

Sending the bad tank back to vans to repair.

Its nice that Vans stands by these and will do the repair, kind of a bummer that it needs done in the first place.

Fuel Tanks 24.5 Man Hours