REFLECTOR: Fuel Vent System

[Richard J. Gentil]

John,

First thing I would do is look at modifying the fuel system so your vents go to a center block on the cabin side of the firewall and then install the one way check valve. My overflow drain runs down the center of the plane and exits at the bottom of the fuselage. 

Once that is complete, pressurize the tanks with an airspeed indicator inline till you show 125 to 150 miles on the airspeed indicator. That should be equivalent to about 1 psi. Then spray all the fittings with soapy water to check for leaks. If you do not see any leaks, leave the system pressurized for a couple of days. If the system is air tight, the airspeed indicator should ack like a barometer. 

Richard

Sent from my iPhone 4

On Jan 30, 2011, at 11:06 AM, Scott Derrick <scott at tnstaafl.net> wrote:

> John,
> 
> the vents are certainly a necessary part of the fuel system. 
> 
> I think the current best practice, since at least 1997,  is to run the vents up to the top of the cabin side of the firewall,  where they join/connect to an aluminum  block, a single line from the block runs down and exits the fuselage floor,  forward of the firewall, in a a small reverse submerged vent.
> 
> I would consider doing something of that nature.  the plans/layout is on line in the builders section.
> 
> Though its certainly possible you have a fuel leak?  My sump was seeping fuel at one time, I had top reseal the seam.    
> 
> Scott
> 
> -------- Original Message --------
> Subject: REFLECTOR: Fuel Vent System
> From: <aminetech at bluefrog.com>
> To: Velocity Aircraft Owners and Builders list <reflector at tvbf.org>
> Date: 01/30/2011 08:45 AM
>> I have an overflow vent installed in each tank.  It runs down inside the wheel well and below the wing in front of the well.  Rear seat passengers complain of a fuel smell in flight and I think it's coming from the vent lines and in through the retract opening.  I'm considering moving these lines to the back side of the wheel well.  Before doing this I would like to confirm that the vents are the source of the fuel smell by blocking the overflow vents.  Before blocking them, I need to know if the vents are a non-essential extra, or necessary.  I've attached pics of the lines to the sump.  Can someone tell me if I have a standard vent system?
>>  
>> Thanks,
>> John
>> 
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