Fuel Tanks DONE!!

A forum in which to discuss topics specific to the assembly of the RV 7/7A.
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RV7A
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Fuel Tanks DONE!!

Post by RV7A »

After almost a year I have finished my fuel tanks!!

I have to admit though that I made a (maybe) big error. When I sealed and riveted on the backplate, I only put a small thin layer of sealant on the two end ribs. I seriously don't know what the heck I was thinking!!

The root rib was no problems at all, I just reached in the huge opening and spread a nice fillet in the corner. The outboard rib of course I can not reach.

So, I will wait a few days and then leak check the tanks. I hope like hell they don't leak, but if they do, I have a feeling it may be from the end ribs. We'll see. The layer I have in there may be enough to seal it up.

A couple of pics are posted in my build log here:

http://www.aircraftstickers.com/RV7A/25sep13.htm

Thanks for everyone's help on answering my questions and listening to me whine and complain about these tanks. Now I feel like the rest of the wing will go together so much faster.

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bullojm1
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Post by bullojm1 »

That is a great looking fuel tank! Look's like you're ready to pressure test with the bike valve already in the fuel drain!

Image
Mike Bullock
http://www.rvplane.com
RV-7 | Superior IO-360 | Whirlwind 200RV
Garmin GTN650 | GRT Dual Sport SX EFIS
Status: FLYING!

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captain_john
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Post by captain_john »

SWEET!!!

Nuttin to it but ta do it!!!

:) CJ
RV-7
Garmin G3X with VP-X & a TMX-IO-360 with G3i
It's all over but the flying! 800+ hours in only 3 years!

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BSwayze
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Post by BSwayze »

Mark,

BIG congrats on getting your tanks finished! Great job! We're on the edges of our seats here, to see how your leak tests come out. Let us know as soon as you're done, will you?

You're absolutely right. Once the tanks are done, most everything else about the wings is downhill. Smooth sailing, for the most part!

And once your wings are finished, the fun really begins. Store those babies in a wing cart and push them aside, and start on the fuselage. I enjoyed the fuselage kit more than any other part of the build, so far. The wings are very repetitious, all those wing ribs, the fuel tanks, endless boring tasks, it seems, with deburring so many edges, etc. But the fuselage is so much more interesting and fun to build. You have all of that to look forward to!

Cheers! :)
Bruce Swayze
Portland, Oregon
http://www.BrucesRV7A.com
RV-7A Working on Firewall Forward

RV7A
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Post by RV7A »

I bought some balloons to leak test my tanks and they are too big. I can't get them to seal on the vent nipple.

I just need to go get some smaller balloons that will fit better. In the mean time, I've been moving on. I just finished deburring, dimpling, and cleaning up all the holes in the rear spars for the skins.

Today I will drill the hole for the pitot tube, and the then probably start deburring and dimpling the skins.

Movin' on... :mrgreen:

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hydroguy2
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Post by hydroguy2 »

electrical tape...round and round and round the vent until you build the diameter up for the larger balloon.
Brian
Townsend, MT

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bruceh
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Post by bruceh »

Go down to the local hardware store or home improvement center and buy some clear plastic tubing. You can flare a short piece of aluminum tubing and put it on the fuel outlet of the tank, then insert the plastic tubing over it. Seal it down if needed with a few turns of safety wire wrapped around the plastic. The plastic tubing is super cheap. Get about 15 feet. Make a long "U" shape that hangs down. This is a "simple manometer" (google it, if you need a visual). You put some water in the tubing so it takes up the space at the bottom of the "U" and up the sides a bit. Lightly pressurize the tank (you are shooting for about 1 psi, so don't over do it). The pressure in the tank will push the water up the other side of the "U". Try to get about 2 feet of difference in the height of the water level on each side of the "U". 1 psi = 27 inches of water. Mark the levels and note the temperature. The water level will rise and fall due to atomospheric pressure and the temperature of the air in the tank. Let it sit for a day and if the water is still uneven in the tubing, you don't have any leaks. Much easier than using the balloon. Be sure to tape up over the gas caps and plug the vent lines.
Bruce Hill
RV-9A N5771H flying over 700 hours!
http://www.overthehills.com/RV-9A-Project
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bullojm1
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Post by bullojm1 »

+1 on Bruce's recommendation on using a manometer. A balloon will deflate over time on its own. Here's my writeup on how I made a manometer and fit it to the tank. Worked extremely well!

http://rvplane.com/?categoryid=3&dayid=248
Mike Bullock
http://www.rvplane.com
RV-7 | Superior IO-360 | Whirlwind 200RV
Garmin GTN650 | GRT Dual Sport SX EFIS
Status: FLYING!

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