[rebel-builders] No action... Tank venting
Posted: Sun Feb 19, 2012 12:04 pm
Not that kind of problem Wayne!! But, since Robert is looking for a problem
to solve...
I recently went through the archives regarding the design and implementation
of tank venting. What I think I learned is:
1) don't vent at the top center of the cabin. Any fuel that comes out the
vent will make a bit of a mess of the roof and could leak into the cabin.
2) Vent at the wing root at one or both wings. Both offers the redundancy
3) Cessna and others have many variations on this theme that are sometimes
good, but very complex to implement.
Looking hard at my wings (already closed) mounted to the airframe and
considering the changing pressure in a tank in flight as well as sitting on
the ground a few thoughts come to mind.
1) No option, you have to vent the tanks!
2) The simple approach (2 above) is an option. This has the disadvantage
with full tanks sitting on the ground (maybe we top off just before we
fly?). As the temperature in the tank rises and falls with sunrise and
sunset, the pressure in the air will push some gas out the vent tube. As
evening sets, the air in the tank will contract and may "gulp" more air to
expand the next day pushing a bit more gas out until some form of
equilibrium is reached, like a big air bubble that is contiguous with the
vent connection.
3) More elegant options all vent at the gas cap or wing tip side of the
tank. This is particularly challenging with closed wings. I could put the
goose neck caps on, but I spent lots of time putting in flush mounting gas
caps. I could install a connection (vent) that vents the upper wing tip
side of the tank and connect it to a vent that is at the wing root.
A few questions:
1) how much of a real issue is this in a moose?
2) How much gas is burped out the vent if the tanks are filled to the top
and the plane is left to sit in the sun?
SR70
Rick Muller
(303) 664 9219 Home
(303) 641 6623 Cell
rickhm@comcast.net
-----Original Message-----
From: mike.davis@dcsol.com [mailto:mike.davis@dcsol.com] On Behalf Of
Wayne G. O'Shea
Sent: Thursday, May 10, 2007 7:41 PM
To: rebel-builders@dcsol.com
Subject: Re: [rebel-builders] No action
I've got this itch Bob..... ;O)
----- Original Message -----
From: "Robert Johnson" <bestofbo@cogeco.ca>
To: <rebel-builders@dcsol.com>
Sent: Thursday, May 10, 2007 9:50 PM
Subject: [rebel-builders] No action
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to solve...
I recently went through the archives regarding the design and implementation
of tank venting. What I think I learned is:
1) don't vent at the top center of the cabin. Any fuel that comes out the
vent will make a bit of a mess of the roof and could leak into the cabin.
2) Vent at the wing root at one or both wings. Both offers the redundancy
3) Cessna and others have many variations on this theme that are sometimes
good, but very complex to implement.
Looking hard at my wings (already closed) mounted to the airframe and
considering the changing pressure in a tank in flight as well as sitting on
the ground a few thoughts come to mind.
1) No option, you have to vent the tanks!
2) The simple approach (2 above) is an option. This has the disadvantage
with full tanks sitting on the ground (maybe we top off just before we
fly?). As the temperature in the tank rises and falls with sunrise and
sunset, the pressure in the air will push some gas out the vent tube. As
evening sets, the air in the tank will contract and may "gulp" more air to
expand the next day pushing a bit more gas out until some form of
equilibrium is reached, like a big air bubble that is contiguous with the
vent connection.
3) More elegant options all vent at the gas cap or wing tip side of the
tank. This is particularly challenging with closed wings. I could put the
goose neck caps on, but I spent lots of time putting in flush mounting gas
caps. I could install a connection (vent) that vents the upper wing tip
side of the tank and connect it to a vent that is at the wing root.
A few questions:
1) how much of a real issue is this in a moose?
2) How much gas is burped out the vent if the tanks are filled to the top
and the plane is left to sit in the sun?
SR70
Rick Muller
(303) 664 9219 Home
(303) 641 6623 Cell
rickhm@comcast.net
-----Original Message-----
From: mike.davis@dcsol.com [mailto:mike.davis@dcsol.com] On Behalf Of
Wayne G. O'Shea
Sent: Thursday, May 10, 2007 7:41 PM
To: rebel-builders@dcsol.com
Subject: Re: [rebel-builders] No action
I've got this itch Bob..... ;O)
----- Original Message -----
From: "Robert Johnson" <bestofbo@cogeco.ca>
To: <rebel-builders@dcsol.com>
Sent: Thursday, May 10, 2007 9:50 PM
Subject: [rebel-builders] No action
Just checking the site. I have not seen any action. Has everyone solved
all their problems. Bob J
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