REFLECTOR: Fuel venting issue

[Scott Baker]

The one-way check valve provides an alternate fuel vent in the event the main vent line becomes clogged from ice (and bugs that might set up house in the lower portion of the fuel vent line).  The check valve keeps fuel vapor and odors from entering the cockpit.  The alternate fuel check-valve system has been working for several years without any known problems - and we feel that it is safe.  Still, I agree with your thinking that a faulty check-valve might allow vapor into the cockpit (when the aircraft is parked).  During engine operation there is a positive flow of air inthe vent lines to displace the burned fuel.
SB 
  ----- Original Message ----- 
  From: Scott Derrick 
  To: Velocity Aircraft Owners and Builders list 
  Sent: Sunday, July 01, 2007 9:35 PM
  Subject: Re: REFLECTOR: Fuel venting issue


  these valves are made for liquid.  one way valves can seep a bit, and you would never know, except in this case... its only held closed by a very small spring.

  I'm trying to think of another plane that has a fuel vent open to the cabin and can't.  The failure mode of  this valve is potentially  catastrophic! 

  Anybody know of any certified or experimental plane that has this configuration? 

  Was this added because somebody crashed? 

  Can Scott Baker explain the reasoning behind this change to the plans and why Velocity thinks this is a safe thing to do?

  Scott

  Brett Ferrell wrote: 
    Then it's a good thing it's not open to the cabin.  The check valve only allows air from the cabin into the tanks....

    B

    Scott Derrick wrote: 
      I have a hard time feeling good about having a fuel vent line open to the interior of the cabin...

      Scott

      Alex Balic wrote: 
The check valve is located inside the plane and above the level of the fuel
in the tanks (right up at the roof- it T's into the vent system, so fi the
external vent fails, it will open and allow air into the tanks from the
cabin- but not let fuel/fumes out into the cabin.

-----Original Message-----
From: reflector-bounces at tvbf.org [mailto:reflector-bounces at tvbf.org] On
Behalf Of David Staten
Sent: Sunday, July 01, 2007 12:49 PM
To: Velocity Aircraft Owners and Builders list
Subject: Re: REFLECTOR: Fuel venting issue

If the check valve is on the same line that is theoretically blocked by 
ice or mud, how is it able to prevent ANYTHING? An obstructed vent is an 
obstructed vent.

Dave

Brett Ferrell wrote:

  The check valve is actually there to prevent tank collapse should the 
vent line become blocked (by say a mud-dauber or ice accumulation).  
I've seen a 15,000 gallon steel tank collapse by a plugged vent, and 
it's not pretty...

B

Scott Derrick wrot

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