X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Received: from fed1rmmtao102.cox.net ([68.230.241.44] verified) by logan.com (CommuniGate Pro SMTP 5.2.12) with ESMTP id 3498469 for flyrotary@lancaironline.net; Wed, 18 Feb 2009 02:14:12 -0500 Received-SPF: none receiver=logan.com; client-ip=68.230.241.44; envelope-from=alventures@cox.net Received: from fed1rmimpo02.cox.net ([70.169.32.72]) by fed1rmmtao102.cox.net (InterMail vM.7.08.02.01 201-2186-121-102-20070209) with ESMTP id <20090218071334.XCCM21647.fed1rmmtao102.cox.net@fed1rmimpo02.cox.net> for ; Wed, 18 Feb 2009 02:13:34 -0500 Received: from BigAl ([72.192.133.251]) by fed1rmimpo02.cox.net with bizsmtp id HKDa1b00J5RcKeo04KDaNs; Wed, 18 Feb 2009 02:13:34 -0500 X-Authority-Analysis: v=1.0 c=1 a=R34hw1QQgDV25NqxX3oA:9 a=jQyJ8HyrepLtwPOq9RHpwlT5aL4A:4 a=ZON7V92nu88A:10 a=udGuzm4V_RlNEblhw-EA:9 a=3_cPIStoXjzseKeQuqoA:7 a=39FoGX3c9YDvZz1MIAnRANZoLbYA:4 a=37WNUvjkh6kA:10 X-CM-Score: 0.00 From: "Al Gietzen" To: "'Rotary motors in aircraft'" Subject: RE: [FlyRotary] Re: hauling gas Date: Tue, 17 Feb 2009 23:14:14 -0800 Message-ID: <2F48DF99BC11403882DA3851AF29967E@BigAl> MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_0019_01C99155.72F13D70" X-Priority: 3 (Normal) X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook, Build 10.0.6838 X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2900.5579 Importance: Normal Thread-Index: AcmRW3UicjvwsZtxQ42lgOzeebWrlQANl6kg In-Reply-To: This is a multi-part message in MIME format. ------=_NextPart_000_0019_01C99155.72F13D70 Content-Type: text/plain; charset="US-ASCII" Content-Transfer-Encoding: quoted-printable But the question remains, in our application, has anyone EVER put a = meter between the aircraft and the fuel nozzle to see if any static voltage exists? Why is it not required for cars? Is there any significant difference The gas pump is clearly grounded to the ground, and the car has no = reason to arrive at the pump with a charge relative ground - at auto speeds there = is no charge buildup due to friction with the air that is not adequately = bled off through the tires, mostly traveling along the surfaces. =20 Keep in mind that the static charge of concern is that caused by the friction between the gasoline and the hose through which it is flowing. = The important thing is having a connection between the nozzle and the fuel = in the tank. When you fuel the car the nozzle is always in contact with = the neck of the tank which is in contact with the fuel. Any electrons = stripped from the fuel by the hose easily travel back to the fuel in the tank - = no charge buildup that might cause a spark at disconnect. =20 In the case of the airplane; it is possible for there to be a residual potential difference (charge) between the ground and the plane if the = plane has just been flying at high speed. It may even be possible that there = is a residual charge of the fuel truck as a result of the recent fueling of another plane. If the nozzle was always put in contact with the plane = away from the open tank prior to fueling (on a metal plane), and remained in contact with the plane throughout the fueling, then the separate ground = lead really isn't doing anything. Connecting the ground lead to the truck = (or fuel pump) prior to fueling assures that when the nozzle is brought to = the open tank there is no static discharge. Or, for example, if the person doing the fueling decides to hold the nozzle away from contact with the = tank while fuel is flowing - like to see when the tank is getting full (Uh, = huh; we've seen that) - and then brings it back in contact; that there will = be no charge to make a spark.=20 =20 If the plane has been sitting for period time (I guess maybe hours), = then any surface charge will have dissipated. If you are then filling from = cans, and if the can has been sitting on the ground before you start fueling - = not really a concern to bring the can to the open tank. Then the important = thing is to make sure there is a conductive path from the fuel in the tank = back to the can. =20 Ok, I guess I've probably already said more than I know. =20 Be aware; be careful. =20 Al G ------=_NextPart_000_0019_01C99155.72F13D70 Content-Type: text/html; charset="US-ASCII" Content-Transfer-Encoding: quoted-printable

But the question remains, in our application, has anyone EVER put a meter = between the aircraft and the fuel nozzle to see if any static voltage exists?
Why is it not required for cars? Is there any significant = difference

The gas pump is clearly grounded = to the ground, and the car has no reason to arrive at the pump with a charge = relative ground – at auto speeds there is no charge buildup due to friction = with the air that is not adequately bled off through the tires, mostly = traveling along the surfaces.

 

Keep in mind that the static = charge of concern is that caused by the friction between the gasoline and the hose through which it is flowing.  The important thing is having a = connection between the nozzle and the fuel in the tank.  When you fuel the car = the nozzle is always in contact with the neck of the tank which is in = contact with the fuel. Any electrons stripped from the fuel by the hose easily travel = back to the fuel in the tank – no charge buildup that might cause a = spark at disconnect.

 

In the case of the airplane; it = is possible for there to be a residual potential difference (charge) between the = ground and the plane if the plane has just been flying at high speed.  It may = even be possible that there is a residual charge of the fuel truck as a result = of the recent fueling of another plane. If the nozzle was always put in contact = with the plane away from the open tank prior to fueling (on a metal plane), = and remained in contact with the plane throughout the fueling, then the = separate ground lead really isn’t doing anything.  Connecting the = ground lead to the truck (or fuel pump) prior to fueling assures that when the = nozzle is brought to the open tank there is no static discharge.  Or, for = example, if the person doing the fueling decides to hold the nozzle away from = contact with the tank while fuel is flowing – like to see when the tank is getting full (Uh, huh; we’ve seen that) – and then brings it = back in contact; that there will be no charge to make a spark. =

 

If the plane has been sitting for = period time (I guess maybe hours), then any surface charge will have = dissipated. If you are then filling from cans, and if the can has been sitting on the = ground before you start fueling – not really a concern to bring the can = to the open tank. Then the important thing is to make sure there is a = conductive path from the fuel in the tank back to the can.

 

Ok, I guess I’ve probably = already said more than I know.

 

Be aware; be = careful.

 

Al G

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