More Tank Testing

Time: 1 Hour

I had a long day at work and office time so I didn’t get much work done I the hangar tonight. What I did do was create two extensions for the tank vent lines with some parts I received from Aircraft Spruce so that I could control any venting.

20140319-211225.jpgI then removed 10 gallons of fuel from the right tank and put it in the left tank. With both tanks half fuel I put both if them on end to test the rear baffles for leaks. So far on the right tank after 3 days I had no leaks!

20140319-211550.jpgI will let these sit for a couple days to check for leaks then lay the tanks on their tops so the bottom skins are up so I can test the top skin rivets. That’s all I did tonight and will get to the left wing ribs tomorrow.

Wing Prep

Time: 3 Hours

I got home from my day trip to Cincinnati this evening and made a quick clothes change to get a little work in the Hangar done. First up was to rivet all the nutplates on the W-423 splice plate that I worked on yesterday. These went pretty fast with the pneumatic squeezer.

20140318-191528.jpgI next grabbed the clecko pliers and removed all the top skins so that I can work on the underlying ribs.

20140318-191729.jpgEvery hole needs deburring and dimpling and that’s a whole bunch of holes. So I grabbed my cordless screw driver with the deburring bit and went to town. Inside and outside of every hole on the top and bottom if the wing. After cleaning up all the holes I used the pneumatic squeezer to dimple all the holes. I used the standard dies for the ribs and the tank dies on the rear spar top and bottom. I only did the right wing since I was a little tired from the early wake up I had today. I will get the left wing done tomorrow night after my flight.

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Splice Plates

Time: 4 Hours

I have limited space on my large workbench as one of my fuel tanks is laying on it full of fuel for leak testing. So in order to keep working I had to skip around on the plans since the large skins would be next but I need the workbench for those. So I moved on to the splice plates that attach the outboard edge of the fuel tanks to the inboard edge of the leading edge section.

20140317-190217.jpgThis plate will get riveted in between the skin and rib of the leading edge. The other side will have nutplates attached for a #8 screw to attach the fuel tank skin to. So I used an K1100-8 nutplate as a guide to drill all the rivet holes.

20140317-190527.jpgWith those holes complete I needed to countersink them to accept a AN4263-3.5 rivet and have the head flush so that the tank skin sits flat.

20140317-190649.jpgI then grabbed the pneumatic squeezer and several dimple dies. For the rivet holes that go along the leading edge skin I used my 3/32 tank dies, this gives just a slightly deeper dimple and will accept the skins dimple better. I will use that die for the underlying rib plus a little countersinking so the two pieces sit well. I had won these dimple dies and planned on using them on the fuel tanks as they were intended to help with the ProSeal that gets under the head of the rivets. I had totally forgot that I won them and they sat in the box until I was cleaning up, oh well the rivets on the tanks came out nice so no big deal. On the other side of the splice I used the #8 dimple die for the screws.

20140317-191155.jpgAfter scuffing up the splice plates with the scotch-brite pads and cleaning them I got both sides primed.

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20140317-215057.jpgI also received my SafeAir EFIS plumbing for the pitot, AOA and static lines. It also has all the connections to complete the setup. I needed this as the plumbing will be in the left wing and very hard to get to when the wings are closed up.

20140317-215556.jpgI will get the nutplates riveted tomorrow after the primer sets up a little.

Tank Leak Testing

Time: 3 Hours

I had planned to start the leak testing yesterday but got a late start on that task in the afternoon when I found a big flaw in my plans. I started by attaching the sump drains after getting some FuelLune from a fellow builder, thanks Glen!

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20140316-114515.jpgWhen I finally got those installed I ran out to the airport where we keep our Lear 45 to grab 20gal of 100LL to do the testing. I was real excited to get this under way and ran home to fill one tank. Simple enough right! I set up the fuel can higher than the wing, placed the siphon hose in the can/wing and pumped away. So what could be wrong you ask? Well I make some dumb mistakes sometime, and this was one of them. If you remember that I placed the flop tube and fuel vent lines on the inboard rib. Well I forgot to get any caps to cover those open fittings to keep the fuel in the tanks! So after a gallon or so I started to hear fuel dripping! I was glad to see it was the fuel lines and not a bad rivet. So I stopped the fueling and got on the laptop and ordered 4 caps and some other supplies I needed. What a bonehead move on my part! Oh well live and learn! After breakfast today my fellow builder Glen bailed me out again with a -6 cap that I could use for the flop tube line and he said to use a plastic hose and clamp for the -4 vent line.

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20140316-115619.jpgI used my safety wire and pliers to secure the hose to the fitting and folded the hose 3 times with a clamp to close the open end. With the lines now securely closed I commenced filling again.

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20140316-115802.jpgI only have two 5 gallon fuel cans so I had to run back out to the airport to get the last 10 gallons. When I got home I emptied those into the tank to make the 20 gallons. After I got all 20 gallons in the tank I found that the hose I had used in the vent line wouldn’t seal tightly to the vent elbow so it was leaking just a little. To prevent this I had to lay the tank flat and remove the clamp from the hose so that the fuel coming from the vent could drain and would have any pressure causing it to leak at the tube/elbow joint.

20140316-142628.jpgSo I will let it sit in this position for a few days then flip it over for the same. Hopefully no leaks, all fingers and toes crossed!

Tanks Done!!!

Time: 8 Hours

Today was the big day to finish up the tanks! After sleeping on it last night and going over all items in the interior I decided that all was done and all I needed to do was seal it up. The plans call for you to place a <3/16th inch bead of ProSeal just forward of the rivet holes so that when you side the baffle in it will act like a squeegee and form a filet. You also need place a bead along the outboard/inboard rib. A common leak point is at the four corners of the baffle so a good size blob goes there. I then spread a small amount around each of the rib rear flange. 20140309-203424.jpgAfter slipping the baffle into place I placed a clecko in every hole to help form the filet.

20140309-203557.jpgThe first rivets are blind rivets at the top and bottom of the 5 middle ribs. I dipped each rivet in ProSeal before setting them to get a good seal.

20140309-203732.jpgNext was to attach the z-brackets with blind rivets. The process was the same and I dipped in ProSeal as well.

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20140309-203849.jpgNext was to attach the 2 end z-brackets. For these I had to use the rivet guy and a bucking bar as the squeezer would fit on the bracket. There are 4 rivets, 2 on each side of these brackets and I was able to squeeze those.

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20140309-204237.jpgThe next task is to rivet all the skin to baffle holes. These I could grab with the pneumatic squeezer pretty easy. The real problem I had was that I found that the countersinks I had done on all these hole wasn’t deep enough! I know that I tested these holes with a rivet way back when I did them but when I set a few rivets they were sitting proud a hair. So I grabbed the countersink cage and set the correct depth and finished them. I removed a clecko, countersunk the hole and then squeezed all the way down the line. So I repeated this for both sides on both tanks which probably doubled the time I spent on them, bummer. Good news is that after that they all turned out great!

Time Lapse

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20140309-204819.jpgHere is a view to the inside so you can see the filet that is made by slipping the baffle in place.

20140309-204921.jpgSo I did a little bit of touch up in those filets but for the most part they all looked good from what I could see. To finish up that sealing I needed to screw the 5 access plates on. I just buttered up the lip of the plates for the area that the cover up on the rib/baffle. They then got placed in their respective spots and I placed a ProSeal dipped screw in each hole. For the inboard ribs I used a cap head screw that uses an allen wrench so that it will be easier to access when the wings are on the fuselage. The others I just used Phillips head screws to attach them.

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20140309-205406.jpgI then cleaned up all the surfaces to remove all the extra ProSeal I got everywhere.

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20140309-205508.jpgI grabbed the fuel caps and placed them in their spots as well.

20140309-205544.jpgThe only thing I couldn’t get done was to attach the fuel drains since I didn’t have a fuel lube for the threads. My friend Glen has some and I will get some tomorrow. For now the tanks will cure in my office with the space heater turned up to 80°! That means next weekend I can grab some 100LL and fill them up for leak testing. So here is my chant, NO LEAKS, NO LEAKS & NO LEAKS!!!