REFLECTOR: Fuel venting issue

[Andrew Ellzey]

Has anyone used coarse steel wool in the vent line
that exits the bottom of the cabin to stop the dirt
dobbers from pluging this line. I would think that
coarse steel wool could be tamped tight enough not to
move but loose enough not to plug the vent. I am
working on my tanks at this time and am planing to try
this on my vent line. Just a thought.

Andy Ellzey


--- reflector at velocityxl.com wrote:

> Yea, the horse is definitiely dead on this one, and
> folks have to do what
> they're comfortable with, but a reliable vent is
> vital.
> 
> But the only way I can see vapor getting into the
> cabin is on the ground.
> If you're running the motor, fuel (mass) is draining
> from the tank pretty
> rapidly, and it has to be replaced or a vacuum will
> be created (and the
> tank crushed). So air is going to go INTO to tank,
> vapor isn't going to
> come out.
> 
> Also, in my experience, check valves fail because
> they're used 'normally
> open', and the spring/closer gets worked. A check
> valve that is always
> closed has very little chance to accumulate gunk in
> the seat, etc, though
> you could do a double-check-valve installation which
> is typical for
> backflow preventers or get self-venting caps if you
> were concerned.  Fuel
> vapor in between the [LINK:
> http://en.wikipedia.org/wiki/Explosive_limit]
> lower and upper explosive limits is going to be
> quite obvious to the nose,
> and so would have plenty of time (IMHO) to make a
> precautionary landing.
> 
> B
> 
> > -------Original Message-------
> > From: Scott Derrick
> > Subject: Re: REFLECTOR: Fuel venting issue
> > Sent: 02 Jul '07 09:09
> >
> > I was thinking the same thing, of installing the
> tee/valve and then
> > running an auxiliary vent line to exit outside
> somewhere else. Thus
> > requiring both vent ports to be clogged before
> there was a problem.
> > Definitely not in the cabin, thats just asking for
> trouble.
> >
> > The major failure mode of having the vent port
> inside the cabin is
> having
> > the main vent plugged and the one way valve
> failing open, thus providing
> > fuel and fumes venting into the cabin. An
> explosive situation, not to
> > mention that fuel vapors are toxic to humans. I
> just replaced a one way
> > valve a few months ago because it was not sealing
> anymore and flowed
> both
> > ways. It happens. And these one way valves do
> seep, they are not a 100%
> > one way.
> >
> > You would never ever see this design in a type
> certified aircraft. Not
> > that that is a prerequisite since nobody
> manufactures a plane as good as
> > the Velocity.
> >
> > I'm sure there are rules (common sense?) about
> having a fuel vent port
> > inside the cabin. Though maybe I'm flogging a dead
> horse on this issue?
> >
> > Scott
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