Attaching Fuel Tank & Flipping Wings

October 5th and 6th, 6h

Given that we had 2 bolts that did not work well with the second fuel tank attachment, we want ahead and removed the second tank.  Then we replaced the bad platenuts.  Then we attached the fuel tank again.  The second time, it worked great.

Afterwards, we proceeded to flipping the tanks into the new cradle. We looked for any twist, and we measure less then 1deg, which is pretty good.

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Attaching Fuel Tanks

August 29th, 9h

Attaching the fuel tanks was a bit time consuming.  The fitting is pretty tight, and having fuel tank sealant in the edges did not help.  So, we have to do couple trials to makes small adjusted, removing some sealant, to get the tank to fit.

Finally, we got the right fuel tank to fit pretty well.

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Then we moved on to the left one. The fitting ended up pretty good as well.  However, we ended having a bit of troubles with 2 bolts going into the platenuts attaching the spar to the Z-bars.  we decided to get back to those bolts later.

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Fuel Tanks Closing and Testing

August 19th, 21th, 26th 11h

I finished closing the second fuel tank: the tank lid and the duel sander.

Afterwards I moved on to testing the 2 fuel tanks. I emailed Vans about the leak in the fuel cap observed in the first tank.  According to them, small leaks in fuel cap are ok since it is in the highest point in the tank, so they asked for adding tape to the fuel cap for the sake of the pressure test.  As well, they pointed a nut that I could adjust to tighten the pressure between the fuel cap and the flange.  After tightening the nut, the leak was way small.  Then I added tape for the test.

After many trials to get a good seal between the balloon and the air vent fitting, I was able to get a good seal and test both tanks.  Both tanks passed the test.

There was no babbles when I sprayed soppy water.  There was a small deflation in the ballon in one of the tests that is expected because of a decrease in temperature of about 20 deg Fahrenheit between the 2 days.  There was an inflation in one of the balloons all the way to explosion after 24h, explained by an increase in temperature between the days.  So, temperature plays a big role in the size the balloon maintains and the deciding factor in the test is the absence of babbles when spraying with soapy water.

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Closing the Fuel Tanks

August 15th, 17th & 23rd, 23h

First we started by verifying all the sealant inside the tanks.  We swept each tank few times, filling any tightly hole we saw with sealant.

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Then we went ahead with closing the tank, we put the baffle and z bars in with cleakos, then we went ahead filling all the holes with wet rivets. We used pop rivets for the center z bars and solid rivets for all the edges. Then we verified that the bottom internal corner stayed open, we put big blob of sealant in the outside corners, and we made sure that there is good fillets on all the edges.

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Following, we put the closing lid and the fuel sander. Everything was set wet, including the screws.

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After closing the tank, we waited a couple days, then we tested one of the tanks.  I used the Vans testing kit to close the the fuel line, I attached a bike pump to the fuel drain, and I attached a ballon to vent line.

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I pumped air in.  Unfortunately there is a huge leak since the tank is not able to hold pressure.  The leak is not from any of the seals we created, but from the Vans fuel tank cap/flange. The small seal in the fuel cap between the lid and the flange is not able to hold pressure  So, we need to replace the fuel cap and maybe the flange.

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The Vans fuel cap/flange used

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Wing Lights Mounting

August 4th & 9th, 15h

Next in the wing light topic is the landing light installation.  The landing lights get installed in the landing light board using screws and springs, so that we can easily adjust orientation as desired.

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Next was cutting the wing tips to install the lights. We did a series of small cuts using a Dremel, to ensure that we only remove the minimum while having ease of installation of the light boards.  We did all the composite work of all the 4 wing tips in the same time.  We also did some small adjustments to the boards, sanding some some sections of the edges, to allow for ease of installation.

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