Right Fuel Tank Fuel Level Sender Wire Installed

Right Fuel Tank Complete!

Here I am displaying my tank as if it were a new car.....

Inboard side

Outboard side

Right Fuel Tank Leak Test

After dealing with the leak repair, I retested the tank. I am escstatic to annouce that the leak is fixed and the balloons are currently holding air. I'm keeping my fingers crossed and will report back in a few days.... Update: After the tank held air for three days I discontinued the test. Right Tank is leak free!

Fuel Tank Leak Fix

After doing a little research, I have discovered that about half of all builders have some sort of fuel tank leak on their first go round. Now, here is the tank repair that I have decided to try first. Special thanks goes out to Mike Stewart, as the idea came from his website.(http://www.mstewart.net/michael/rv/wings/tankrepair/tankrepair.htm)

Here's the Fix. -First gather up the tools shown above.
1)  pop rivet puller 2) Two AD-41H Closed End pop rivets 3) Bulb Syringes(cut the tops off to use as a straw) and/or a small medical syringe w/ 1/8" heat shrink tubing or small diameter straws 4) popsicle sticks and brush. 5) Acetone/MEK and rags

Mark where the leaks are coming from and drill a 1/8"hole(#30 bit) on the upslope side of where you will tilt the tank for drying.

Now, Mix up some proseal and thin w/acetone. Next, slowly suck or pull up the proseal and insert it into the tank holes. Do this several times in each hole and tilt the tank to allow the sealant to run over the leak, from the inside. Finish things off by applying some proseal to the pop rivets and riveting them in place.

Finally, anchor the tank in place, at a tilt, and connect an air hose with a low pressure setting. Let the air blow slowly through the tank for a few hours a day, for about three days. Now, disassemble everything and retest the tank.

Leak #2. Another fix:  1/2013 (Upper outboard seem on right tank).

I used a circle cutter to cut the outboard rib. I then drilled out the offending rivets, cleaned out the old proseal, reapplied proseal and rivets, and applied a fillet to all reachable seams.I finished off things by prosealing and pop riveting the solid cover plate over the access hole.  Note: (closed end pop rivets were used). Leak test Good, re-installed on a/c. ;)

Fuel Tank Leak ARRRRRRRGH!

Today, I finally decided to leak test the right fuel tank. First, I capped off the main fuel pick up line, then I connected balloons to the fuel vent and return lines. Finally, I wrapped a latex glove around the fuel cap and inserted the valve stem connector into the fuel drain.(see left tank for details)

Now for the bad part...... I commenced with the test. Using the valve stem connector, ordered from Vans, I slowly pumped air into the tank. The balloons slowly filled and I started to spray a soap and water mixture over the entire tank. Then I found it. On the top outboard corner of the rear baffle(one rib in from the fuel cap) there was a leak.

In the words of Micheal Stewart,"After doing all the work on the tanks... to find out there's a leak is like waking up with your left arm cut off. Extremely depressing."

Time to do some research on the fix........ At least I found it now, right?
It still doesn't make me feel any better.

Finished Sealing Up The Right Tank!

Today I sealed up the last remaining piece to the right fuel tank, the access plate. I chose to seal the plate directly to the rib without using the cork gasket. I soaked and cleaned all of the screws and surface area with M.E.K. before applying the proseal. After the fitting and drying, I will test the tank for leaks.

As with the left tank, I ended up having to drill out most of the inboard leading edge assembly rivets and fabricate a .32 shim. After cutting, drilling, deburring, dimpling, priming, and installing the small 5 to 6" long shim, I reriveted the LE assembly together. All of this work was done in order to eliminate a little minor pillowing at the top outboard leading edge of the fuel tank. (where the joint plate meets the LE assembly) *Note- This is my aerobatic tank, don't forget to attach the fuel float sender wire before final install of the tank to spar. I've read that 20-22 awg wire is sufficient.

Sealing the Rear Baffle

Sealant was applied to the rib end flanges and tank skin. A 3/16" bead of proseal was spread just forward of the rivet holes.

A thick blob of the "Black Death" was applied to the corners.

Pnuematic Sealant Gun

Here is a nice tool to have. I borrowed this sealant gun from a friend to spread out the 3/16" bead of proseal on the rear baffle.

Right Tank Ready For Rear Baffle!

The float had to be moved to the second bay due to the inverted flight mods. Here is a shot of everything adjusted and sealed in place. I know, I go a little heavy on the proseal

Everything inside sealed, cleaned, and ready for the rear baffle. I chose to put some proseal over the reinforcement ring and nutplates. Double check everything here! Look over the plans again. Check all inverted flight mods- trap door, anti hangup brackets, anti rotation bracket, safety wire, etc...

Right Fuel Tank Accessories Fitted and Installed

Installed Fuel Vent and Vapor Return Line. Also, I put some proseal on the anti-hangup bracket (as shown). This will prevent any chaffing that might occur from the flop tube rubbing against it.

Fuel vent angled upward.

Ready for the final rear baffle to be installed.

Test Fit for Inverted Flight Flop Tube

Notice the Anti-Rotation bracket near the leading edge. Here you can also see the two anti-hang up brackets I installed, one on the left of the flop tube end and one on the right side. I will replace the cleco w/a rivet after the proseal install is complete.

Anti-hang up bracket and fuel trap door installed.

Sealed the Outboard Rib

I riveted and sealed the leading edge reinforcement plate. I went ahead and placed an AN470-AD6 rivet in both the Front and Aft tooling holes.

Sealed the Fuel Drain

Sealed the Fuel Cap Assembly

Outside shot. I back riveted the flange.

Update: The vent line clip is in the wrong location here. It was relocated to the bottom soon after the pic.
Inside shot. The piece in the upper right is the fuel vent line clip.

Sealed the Stiffeners

Right Fuel Tank Prep

I drilled out and countersunk the fuel cap assembly. The cap is contoured, so be sure to get it lined up properly with the shape of the tank skin.

I drilled out the right tank fuel drain.

I deburred everything and used the soldering iron to remove the blue plastic vinyl. I will be dimpling all holes tomorrow....

Inverted Flight Fuel Tank Mod Pt.2

I fabricated the fuel tank trap door for the second rib. This little guy consumed a couple of hours of work. The pin will be held in place by the rear tank baffle. I left a little gap ,at the bottom of the door, for a layer of proseal on the bottom rib flange.

Here is the inside rear baffle. I fabricated the support doubler for the fuel level float. It had to be relocated to the second fuel bay as a result of the flop tube occupying the first bay .

Outside rear baffle. Support doubler and nutplates riveted in place. I countersunk the support doubler and dimpled the rear baffle(shown).

Inverted Flight Mod Pt.1

I clecoed the leading edge support bracket(previously fabricated and primed) and inside rib support in place.

I drilled out the hole for the flop tube AN fitting. I started with smaller bits and finished off the hole with a unibit.

I connected the flop tube for a test fit.

I drilled out the vent and vapor return line holes, in right inboard rib.

Drilling holes in Right Fuel Tank

Drilled out FT Top Edge holes to #19. They will later be dimpled to accept #8 screws.

Countersunk #40 holes, second row down from the top of the fuel tank. This row can not be dimpled due to the rear baffle going in place beneath the skin. I also deburred every hole, as necesssary, on the fuel tank.

Right Wing Fuel Tank Z Brackets