REFLECTOR: Grounding Point
Ronnie Brown
romott at adelphia.net
Sat Oct 30 11:53:17 CDT 2004
My records show that this newly built Velocity burned to the ground during refueling.
Aircraft Description
Serial Number 304 Type Registration Individual
Manufacturer Name BALL M A Certificate Issue Date 11/22/1996
Model VELOCITY 173 RGE Mode S Code 52031607
Year Manufacturer None Cancel Date 08/08/2001
Reason for Cancellation Destroyed Exported To
--------------------------------------------------------------------------------
Aircraft Registration prior to Deregistration
Name BALL MELVIN A
Street 14860 ROLLING HILLS DR
City MONTROSE State COLORADO Zip Code 81401-8031
County MONTROSE
Country UNITED STATES
----- Original Message -----
From: Jim Sower
To: alex157 at direcway.com ; Velocity Aircraft Owners and Builders list
Sent: Friday, October 29, 2004 1:01 AM
Subject: Re: REFLECTOR: Grounding Point
Didn't hear about that one. Wonder what the particulars are.
Cessna has rubber bladder tanks IIRC. RV (and everyone else) is all metal. I'm questioning the assertion that grounding my chain (which goes over the metal fuel orifice into the tank bottom) won't work because there's no adequate path to ground (while implying that the screen WILL provide an adequate path). My setup has at least as good a path than any spam can, since they don't even have a chain and make no attempt to ground the fuel streaming out of the nozzle (which is said to be the source of static charge). This screen seems more effective than my chain, but my chain is more effective than 99% of GA aircraft (dramatically more effective than Cessnas with bladders) and is dirt simple, practically free, and 90% installed before you even start thinking about static discharge.
Alex Balic wrote:
Hey Jim-
As I recall, several/a few years ago, a Velocity was lost due to a refueling fire- can't remember who it was, but it generated a lot of interest on the reflector at the time-
As far as a Cessna, or an RV having problems, I would guess that they generally do not since you can ground(equalize) the entire airframe very easily to the fuel truck through the ground cable, as long as you attach it to somewhere on the airframe since the airframe itself is conductive all of the way to the fuel cap rings. The problem that we, lancair, Glassair ect have is that it is difficult to ground the refueling point through other areas of the aircraft.
Alex
-----Original Message-----
From: reflector-bounces at tvbf.org [mailto:reflector-bounces at tvbf.org]On Behalf Of Jim Sower
Sent: Thursday, October 28, 2004 4:12 PM
To: alex157 at direcway.com; Velocity Aircraft Owners and Builders list
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
__
------------------------------------------------------------------------------
_______________________________________________
To change your email address, visit http://www.tvbf.org/mailman/listinfo/reflector
Visit the gallery! www.tvbf.org/gallery
user:pw = tvbf:jamaicangoose
Check new archives: www.tvbf.org/pipermail
Check old archives: http://www.tvbf.org/archives/velocity/maillist.html
-------------- next part --------------
An HTML attachment was scrubbed...
URL: http://www.tvbf.org/mailman/private/reflector/attachments/20041030/d4bf94d6/attachment.htm
More information about the Reflector
mailing list