REFLECTOR: Fuel venting issue

[reflector at velocityxl.com]

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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