REFLECTOR: Grounding Point

[Gilles Gratton]

We are talking retrofit here.  My plane has been flying (and refueling) for
4 years and I only clip the grounding cable to the nozzle for lack of a
better grounding point.  However I like the screen bit.  Would it work if
one was to shape a cylindrical screen that could be inserted in the fuel cap
opening at every fuel stop.  This cylinder could reach the bottom of the
tank and have a flange that would barely touch the top strake around the
fuel tank opening. The fuel nozzle would then  flow through that screen.
The only draw back would be to carry (and store ) this contraption to have
it on hand at every refueling stop.
Gilles

-----Original Message-----
From: reflector-bounces at tvbf.org [mailto:reflector-bounces at tvbf.org]On
Behalf Of Jim Agnew
Sent: 24 octobre 2004 14:43
To: Velocity Aircraft Owners and Builders list
Subject: RE: REFLECTOR: Grounding Point


The concept of a fire screen has been proven for many years in miners lamps.
A
fine mesh screen tube surrounding the filler inlet that goes to the bottom
of
the tank will prevent the passage of the flame front into the fuel tank even
if
the fuel vapors inside the fire screen tube ignite.  This screen does not
depend on grounding.

Jim


--- Chuck Jensen <cjensen at dts9000.com> wrote:

> Mmmmmm. Alex's idea of first checking for continuity between the fueler
ring
> and the exhaust pipe is a good one.  If there is continuity, then
executing
> Al's idea of a drooping chain from the cap down into the fuel seems to
> assure there is a fuel-chain-exhaust-refueling stating ground (all this
> assuming there is fuel ring to exhaust continuity).  Richard's method,
from
> a Very Large Aerospace Company, appears to do the same thing, just better
> and with a higher degree of certainty.  Of course, if there's not
> continuity, then its back to the drawing board.  It's somewhat comforting
to
> know that the incidence of Velos going off like Roman Candles is rare, but
> I'd hate to be the first data point.
>
> Chuck
>
> -----Original Message-----
> From: reflector-bounces at tvbf.org [mailto:reflector-bounces at tvbf.org]On
> Behalf Of Richard Riley
> Sent: Sunday, October 24, 2004 11:44 AM
> To: Velocity Aircraft Owners and Builders list
> Subject: RE: REFLECTOR: Grounding Point
>
>
> We went around and round on this topic on one of the canard mailing lists
a
> few months ago.  Following all the suggestions, I talked with a fuel
system
> designer at the Very Large Aerospace Company where I work and came up with
> the following for my plane...
>
> The fuel cap ring is attached to a coarse brass screen, shaped in a tube,
> that goes from the fuel cap ring to bottom of the tank.  It is attached by
> a brass ball chain to the fuel drain, and to a brass bolt in the outboard
> fuel bulkhead.  That bolt is then attached by a wire to the engine, and
> therefor to the exhaust pipes.
>
> Most of the static charge in refueling is created by the fuel falling from
> the nozzle to the surface of fuel in the tank.  The brass screens strips
> that away.  No matter what the level of the fuel, it's pierced by the
chain
> going to the fuel drain.  And then the whole thing is electrically bonded
> to the engine block.  If the fuel truck attaches the ground strap to the
> exhaust pipe, all the potential is equalized.
>
>
> At 09:21 AM 10/24/04, Al Gietzen wrote:
> >I guess there are different views on this, but I see little relation (as
> >in maybe "none") between grounding the exhaust pipe, and refueling
> >safety.  The static charge buildup is between the nozzle and the fuel
> >(surface); or the nozzle and the potential existing static charge on the
> >surface of the strake due air friction.  So have a metal chain or cable
> >from the cap ring hanging into the fuel, and keep the nozzle against the
> >ring; and, if you have just landed, wipe the surface of the strake with a
> >damp cloth before contacting the nozzle to the ring.
> >
> >Anyway, that's my take; but I've been wrong once before in my lifeJ.
> >
> >Al
> >Subject: REFLECTOR: Grounding Point
> >
> >I didn't find a direct reference in the archives, so I was still
wondering
> >if the exhaust pipes is an adequate grounding point when refueling?  I
> >always assumed it was but I'd hate this to be a FireBall Falacy.
> >
> >Chuck
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=====
James F. Agnew
Jim_Agnew_2 at Yahoo.Com
Tampa, FL
Velocity 173 Elite Aircraft Completed & Flying
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