Fuel tank fails to feed

[Gerald McKibben]

BC12D N95522 - I had stated this thread back in November or December; don't see it now but it must have been lost in the shuffle.

My left wing tank won't begin feeding to the main tank without some rocking back and forth. After that it continues to drain until all six gallons have drained. I was told by someone on this forum that this is a common T'Craft problem and to check to see if there is an air leak around the filler neck. Sure enough, after I blew through a plastic tube on the end of the tube on the cap I could hear air rushing out. The right wing tank is airtight, and it feeds the way it should.

I bought some of that fiber gasket material, 1/32 in thick, and made a gasket and put it on over the existing gasket - which looked OK. In fact, the fit seemed to be plenty tight without another gasket. After putting the extra gasket on, it was hard to get the cap on it was so tight. But it still leaks. I'm beginning to think there's a leak somewhere other than around the filler cap.
Any ideas?

[Bird]

Re: Fuel tank fails to feed

Put some liquid dishwasher detergent around the out side and blow, follow the bubbles.
As for the problem that the tank doesn't want to normally drain without rocking seems to point to something in the tank--two different problems?

[woodmw]

Re: Fuel tank fails to feed

Swap the left and right caps and see if the leak follows the cap.

[Gerald McKibben]

Re: Fuel tank fails to feed

I swapped them and the leak was still in the left side. The caps are made different though.

Swap the left and right caps and see if the leak follows the cap.

[woodmw]

Re: Fuel tank fails to feed

Don't know if there enough filler neck sticking, but you might be able to use Hank's method of blowing up a condom and slipping it over the neck. If the condom holds air, the tank/filler neck are sealed and the cap seal is suspect. If this is the case, you could fill the tank, raise the tail to level, and open the valve to check flow from wing to main with the condom pressurizing the tank. If the condom doesn't hold pressure, I would suspect the seal between the tank and the filler neck.

[Hank Jarrett]

Re: Fuel tank fails to feed

I would bet you have an additional leak in the tank or the filler neck. Does your cap by any chance have the little hole drilled in the back of the curved breather tube? That small hole that some people put in in case the tube gets plugged totally destroys the whole reason for the curved breather tube. If it is there, SEAL IT OFF!

The other thing to check is the condition of the filler neck contact surface. If there is a radial cut in the surface the seal may not "seal". You can test the system for leaks by putting a condom (OK, don't laugh) over each filler neck, disconnecting the fuel line from the carb and blowing back through the fuel line to "inflate" the fuel system. The condoms are to protect the fuel tanks from over pressure and NEVER (NEVER NEVER NEVER!) put shop air into the fuel system! The condoms should inflate and HOLD AIR. Then have someone shut off the firewall valve and wait. My fuel system held air with the condoms inflated for over an hour.

Take pictures, the reactions are GREAT when you show them. I promised to show the pharmacist the pictures. I REALLY don't think he believed what I wanted them for till he saw the photos.
Couple of hints, DON'T get any fuel (even a drop) on the condom, it will pop, and you DON'T have to put a bag over your planes head to do it like I did, I was just trying to keep the cockpit clean.

By the way, those things cost a LOT more now than when I was in High School.....not that I ever bought them back then. You know, they were just in those vending machines in gas stations, that's all. Honest!

Hank

Come on. I was chief Nerd in High School. What would I ever do with a condom?

[cvavon]

Re: Fuel tank fails to feed

Jerrett the red headed irish women is laughing her @ss off at this one she said only a scott could come up with some thing like this
chuck

[Hank Jarrett]

Re: Fuel tank fails to feed

It's a good thing I played Contra Bass Clarinet in my youth. It takes a a LOT of lung to fill up a Taylorcraft fuel system, and I only have one wing tank.

Hank

As a added advantage, the Piper next door didn't get pregnant.

As an added bit. Measured the angle on the stab today. You aren't going to believe it. 10*!!!! Multiple checks, it is TEN Degrees.

[M Towsley]

Re: Fuel tank fails to feed

Wow, Hank, I'm impressed...

[cvavon]

Re: Fuel tank fails to feed

Wow same as my plane with tall tail wheel and bush wheels

[Hank Jarrett]

Re: Fuel tank fails to feed

I REALLY didn't expect that! Your tail wheel and spring must be a lot taller than I thought.
Hank

[Bird]

Re: Fuel tank fails to feed

Hmmm I -unn well yeah I would put a sheet over my head er project too Hank
Okay but to the 2nd point guys -he has to shake back and forth to get the tank to start to drain??? comments?
Don't even think about the condoms at this point, damn good thing there isn't a urologist watching this thread

[Robert Lees]

Re: Fuel tank fails to feed

...Does your cap by any chance have the little hole drilled in the back of the curved breather tube? That small hole that some people put in in case the tube gets plugged totally destroys the whole reason for the curved breather tube. If it is there, SEAL IT OFF!

I disagree. The pressure from airflow with the forward-facing tube will not be diminished THAT much by a tiddy hole in the back face of the tube. Lack of regular inspection of the tube (and a wasp's nest) could crumple the tank.

The main reason for lack of flow is (as already reported) poor sealing caps, or too-small diameter pipe to the fuselage tank; hence the Gilberti/Harer pipe size requirement).

Aside: I'm also an ex-clarinetist, Grade 8 standard in 1980 (when I was at school, and played in several orchestras, and played at the Royal Albert Hall in London), but after school I progressed to penny-whistles due to easier transportation & cleaning.

Later, I was threatened with arrest from PC Plod for playing on the Albert Hall, serenading the tarts in the local flats, but I got away with a well-meant caution. Aaaahhhh, student life, eh?

[Robert Lees]

Re: Fuel tank fails to feed

...urologist ....

Is that someone who takes the piss?

[Howard Wilson]

Re: Fuel tank fails to feed

Could be a clogged line. Then you wouldn't need a condom...... baritone sax h