REFLECTOR: Grounding Point
John Dibble
aminetech at bluefrog.com
Fri Oct 29 10:57:58 CDT 2004
I wonder if sliding across the seat was the source of the static
charge. Think I'll stay out of the car/plane and not rub anything when
fueling.
John
velocityxlfg wrote:
> My sister in Law was Badly burned refuelingHer car. In the winter time
> she got back in her carto get warmed up. When the fueling was done
> she got out and grabbed the fuel nozzle and poof.She had a big ball of
> flame coming out of the fuel tank.The worst part was this scared
> herand she pulled the nozzle out of the tank and sprayed gas on the
> side of the car. Now she had a nice big fire. Tip never pull the fuel
> nozzle out of the tank if there is a fire. It just add fuel to the
> Fire.
> RON
>
> ----- Original Message -----
> From: Jim Sower
> To: alex157 at direcway.com ; Velocity Aircraft Owners and
> Builders list
> Sent: Thursday, October 28, 2004 5:12 PM
> Subject: Re: REFLECTOR: Grounding Point
> <...not any way for the charge to pass to the chain ...>
> So how does it get go ground on a Cessna or RV?
>
> BTW, in the interest of perspective or context, does anyone
> on this list have first-hand (saw it happen) or second-hand
> (personally knows a reliable first-hand witness) of a
> refueling fire caused by static charge on ANY airplane? Or
> automobile, for that matter?
>
> Inquiring minds need to know ... Jim S.
>
> Alex Balic wrote:
>
> > the fuel itself is non conductive, it is the charge that
> > is stripped from
> > the surface of the flowing fuel that builds up on the
> > surface of the skin
> > and metal parts that causes the problem, the metal chain
> > in the fuel trick
> > is not effective, since there is not any way for the
> > charge to pass to the
> > chain.
> >
> > -----Original Message-----
> > From: reflector-bounces at tvbf.org [
> > mailto:reflector-bounces at tvbf.org]On
> > Behalf Of Scott Derrick
> > Sent: Sunday, October 24, 2004 4:56 PM
> > To: Velocity Aircraft Owners and Builders list
> > Subject: RE: REFLECTOR: Grounding Point
> >
> >
> > If an airplane has capacitive fuel sensors, Doesn't that
> > provide a ground
> > path from the fuel in the tank to the exhaust pipe?
> >
> > Scott
> >
> > At 02:16 PM 10/24/2004, you wrote:
> >
> > > 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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