Transfer from wing tanks

Fuel tanks, systems and parts
Paul Agaliotis
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Re: Transfer from wing tanks

Post by Paul Agaliotis » Mon Nov 15, 2010 21:15

Still sounds like a cap vent to me. Wing tanks use non-vented caps and the nose uses a vented cap. If you use the NAPA cap it must vent in both directions. The cap gaskets are bad it will also cause slow draining.
Paul
Mailing Adress : Paul Agaliotis 2060 E. San Martin, San Martin,Calif. 95046

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rkittine
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Re: Transfer from wing tanks

Post by rkittine » Tue Nov 30, 2010 17:09

That is a great question, so when I flew last I kept an eye on the underwing vent tube. The vent pick up is above the fuel level in the tank or it would drain the tank with a vented cap (the norm) and is there to allow air in to replace fuel that has flowed out even though it comes out on the lower side of the wing. The pressure in the tank does not push fuel up to the vent pick up and therefore does not leak any fuel in flight with ram air into the cap.

I believe the addition of the metal cover over the tank, replacing the fabric and covering more of the cap, coupled with the more efficient lift (low pressure area over the wing and hence the cap) created by the Vortex Generators, probably made my installation more problematic than on a standard Champ wing mounted tank.
Robert P. Kittine, Jr.WA2YDV
West Nyack Aviation, L.L.C.
New York, New York 631-374-9652
rkittine@aol.com

Paul Agaliotis
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Re: Transfer from wing tanks

Post by Paul Agaliotis » Tue Nov 30, 2010 18:39

Robert,
The tank vent I'm talking about is the fuselage tank cap. The NAPA vented cap allows air to enter as fuel is used. The Aeronca cap needs to let air escape as fuel enters the tank.
The venting issue has been around since Truman was in office. It boils down to a blockage in the vent system or a bad cap gasket.
Paul
Mailing Adress : Paul Agaliotis 2060 E. San Martin, San Martin,Calif. 95046

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rkittine
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Re: Transfer from wing tanks

Post by rkittine » Wed Dec 01, 2010 14:34

The vent in the cap of the main tank is fine and the transfer worked fine until I changed the airfoil around the wing tank cap (the metal cover replacing the fabric - straight sheet rather then the contoured fabric, whcih made the cap sit down into the opening farther) and added the Vortex Generators - i.e. more Negative Pressure on the top of the wing. They it would only transfer if I manevered the wing around a lot to get it started and disrupted the airflow over the wing. It now works every time instead of once in a while.
Robert P. Kittine, Jr.WA2YDV
West Nyack Aviation, L.L.C.
New York, New York 631-374-9652
rkittine@aol.com

Paul Agaliotis
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Re: Transfer from wing tanks

Post by Paul Agaliotis » Wed Dec 01, 2010 16:19

Glad your airfoil shape change worked out for you.
Paul
Mailing Adress : Paul Agaliotis 2060 E. San Martin, San Martin,Calif. 95046

Holcombe
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Re: Transfer from wing tanks

Post by Holcombe » Wed Dec 01, 2010 21:39

I started this, and have been following along. I have not had a problem again in over a year and have come to the conclusion that the key is how well the wing tank cap seals. If it is sealing properly, it doesn't matter how low the pressure is on the top of the wing. The tank will have positive pressure from the underside overflow vent. The fuel will flow just fine. If the cap is on a little funny and the seal leaks, there will be low pressure in the top of the tank and the fuel not want to flow as it shouldl.
That is my final two cents and I'm sticking with it, and not putting a forward facing vent on my tank cap.
richard
Tail winds are a "Good Thing"

Paul Agaliotis
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Re: Transfer from wing tanks

Post by Paul Agaliotis » Wed Dec 01, 2010 22:21

Richard,
Thats kind of been my take on the draining issue. It tends to be a vent or cap issue. Robert feels satisfied with his installation so there must be many ways to skin a cat.
The forward facing vent will certainly do the job, but it would also indicate that the original system is not.
Paul
Mailing Adress : Paul Agaliotis 2060 E. San Martin, San Martin,Calif. 95046

Holcombe
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Re: Transfer from wing tanks

Post by Holcombe » Thu Dec 02, 2010 12:38

Of course if you go to a place with mud daubers or wasps, all bets are off. Pitot tubes and fuel vents are first in line as nesting sites.
I carry a length of soft copper wire that can be run up either to clear a passage for air.
Tail winds are a "Good Thing"

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rkittine
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Re: Transfer from wing tanks

Post by rkittine » Fri Dec 03, 2010 13:15

Hey Richard, Thanks for the insight. That is the one thing that I never tried. The cap that I had originally on the wing tank was a VENTED cap. I thought that was what I was supposed to have. I did not try an unvented cap, so that will be something I will go and try now. I will put an unvented cap on in place of my modified one and see is I get consistent transfer.
Ciao - Robert
Robert P. Kittine, Jr.WA2YDV
West Nyack Aviation, L.L.C.
New York, New York 631-374-9652
rkittine@aol.com

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joea
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Re: Transfer from wing tanks

Post by joea » Fri Dec 03, 2010 20:29

Robert,

The Sedan's use non-vented caps. Its a no-no from the factory to use a vented cap on this model, so may be something that transferred over.

Joe A

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Re: Transfer from wing tanks

Post by Holcombe » Sat Dec 04, 2010 13:13

In my travel pac of stuff I carry when flying out of town there are two fuel tank covers, one vented, one not. the main tank must be vented, the wing tank can't be.
How complicated our little planes get!
It is surprising how few tools one needs to change a tire, replace a spark plug, or cover an ouch! with duct tape.
Whenever I service anything on the plane, I watch exactly the tools I use and make sure they are in the travel pack. Some safety wire, a few gaskets, nuts, bolts, screws, all chosen to fit. Also a replacement quick drain. I had one jam open once on an otherwise fine morning, alone, at a lovely mountain campsite/grass strip.
Tail winds are a "Good Thing"

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