REFLECTOR: Grounding Point

velocityxlfg velocityxl at fastmail.fm
Fri Oct 29 07:57:01 CDT 2004


My sister in Law was Badly burned refueling
Her car. In the winter time she got back in her  car
to 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 her 
and 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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