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tank - vent on a pumped engine

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tank - vent on a pumped engine

Old 05-17-2004, 02:30 AM
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grego
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Default tank - vent on a pumped engine

I am fitting a 120 thunder tiger with a pump in a fun plane.
As it is pumped, I need to have the fuel tank vent/overflow constantly open.
What do I do to prevent overflow during aerobatic manouvers and self draining

Your input is warmly appreciated
thank you all
grego
Old 05-17-2004, 07:41 AM
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Flypaper 2
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Default RE: tank - vent on a pumped engine

Easiest way is to use a three line tank. Fill line goes top front of firewall, through the tank ending at the bottom of the tank. Overflow goes bottom front of the firewall, through the tank and to the top of the tank. third line goes from the pickup to the pump. Fill through through the top line till it comes out the bottom.
Old 05-18-2004, 05:23 AM
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grego
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Default RE: tank - vent on a pumped engine

thanks for that input , flypaper 2.
That will work fine I am sure
regards
grego
Old 05-18-2004, 06:53 AM
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Mike James
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Default RE: tank - vent on a pumped engine

If you keep the fuel tank vent open, you'll lose whatever pressure the engine pumps into the tank.
The first image shows a typical way to do a pumped engine. My image shows the optional use of a small header tank. Just ignore that part.

The second image shows a more typical sport-type installation.
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Old 05-18-2004, 08:00 AM
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rcflier_gi
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Default RE: tank - vent on a pumped engine

What type of pump is on the Thunder Tiger ? My OS 1.20pump requires the tank vent to left open as it's pump requires no tank pressure.
Old 05-18-2004, 09:39 PM
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Default RE: tank - vent on a pumped engine

I guess there are two types. The perry type will supply pressure to the carb/regulator. The other type will add pressure to the system and regulate the flow.
Old 05-18-2004, 11:32 PM
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grego
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Default RE: tank - vent on a pumped engine

thank you kindly for your input.
As other have pointed out in the meantime , there must be different pumps-systems, or as we say here in NZ :" there is many different ways to skin a cat" !!!!

The thunder Tiger pump sucks the fuel out of the tank and pumps it into the carby.
So the tank has to stay vented otherwise there is a vacuum created and it all comes to grinding halt.

Mind you, with my flying skills it will end up coming to a grinding halt anyway
regards
grego
Old 05-19-2004, 08:18 AM
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rmh
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Default RE: tank - vent on a pumped engine

try this for simple non leaking vent--
one clunk line feeds engine
One vent line at top front of tank- wraps back behind tank -then exits to a L facing forward, at bottom of fuselage.
Old 05-19-2004, 08:25 PM
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Azcat59
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Default RE: tank - vent on a pumped engine

If you are running the Perry type pump, which it sounds like in your case, the vent line must remain open. The clunk line goes to the pump, through the pump and on to the carb. The vent line should be at the top of your tank, when you fuel up, it will run over and show you it is full. Bring that line out the bottom of the plane around the firewall area, and cut a 45 degree angle on the line so that it is facing into the slipstream. You will lose no fuel during manuevers.

To fuel up, use either a third line with a fuel dot, or the DuBro type fueler, between the tank and the pump, on the clunk line.

Clair
Old 05-19-2004, 08:58 PM
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Jim Thomerson
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Default RE: tank - vent on a pumped engine

One way valve in the vent line? That's what I do with non-pressurized tanks.

Jim
Old 05-29-2004, 05:29 AM
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grego
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Default RE: tank - vent on a pumped engine

hey Jim,
that sound really intresting.
Where would I be able to purchase such a non return valve

regards
grego
Old 05-29-2004, 05:44 AM
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Mike James
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Default RE: tank - vent on a pumped engine

You can buy the YS "check valves", which are really nice, and many hobby shops carry other brands as well. I've even used these on normally "muffler pressurized" systems, and they do help maintain tank pressure.

Just don't forget the most important caveat about any pressurized system... When you've landed and are ready to refuel, release the pressure through the vent line (with the tube facing away from everybody's face!) before you fuel up. When I first flew some YS-equipped Pattern planes, I sprayed myself in the face more than once... Don't do it. Nitro has a bitter taste, and is no good for your eyes.

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