X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Received: from EXHUB003-3.exch003intermedia.net ([207.5.74.110] verified) by logan.com (CommuniGate Pro SMTP 5.2.12) with ESMTPS id 3485814 for flyrotary@lancaironline.net; Tue, 10 Feb 2009 10:16:05 -0500 Received-SPF: none receiver=logan.com; client-ip=207.5.74.110; envelope-from=jwhaley@datacast.com Received: from EXVMBX003-5.exch003intermedia.net ([207.5.74.45]) by EXHUB003-3.exch003intermedia.net ([207.5.74.110]) with mapi; Tue, 10 Feb 2009 07:15:27 -0800 From: Jeff Whaley To: Rotary motors in aircraft Date: Tue, 10 Feb 2009 07:15:24 -0800 Subject: RE: [FlyRotary] Re: hauling gas Thread-Topic: [FlyRotary] Re: hauling gas Thread-Index: AcmLi5KzwBNt2fpZSVGiTBYPLseEcwABWLkg Message-ID: References: In-Reply-To: Accept-Language: en-US Content-Language: en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: acceptlanguage: en-US Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: quoted-printable MIME-Version: 1.0 Good ideas Ernest ... Of note is that in the electronics world we wear thes= e every day; we also have to test them every day; they don't last forever .= .. the ground strap should measure 1 Mega Ohm. Jeff -----Original Message----- From: Rotary motors in aircraft [mailto:flyrotary@lancaironline.net] On Beh= alf Of Ernest Christley Sent: Tuesday, February 10, 2009 9:22 AM To: Rotary motors in aircraft Subject: [FlyRotary] Re: hauling gas Al Gietzen wrote: > > My simple approach is to use a metal chain, which serves as cap retainer, > which hangs from the metal cap flange into the fuel, back to the cap. > Contacting the end of the hose to cap/cap flange prior to removal takes c= ar > of any residual. Maintaining contact between the hose and the flange > (keeping the cap chain, or cable, hanging into the fuel) keeps fuel and h= ose > at the same potential. > > =20 Al, you're giving me the heebee-jeebees here. The problem is that the can and fuel in the tank may already have a=20 differential charge built up. Then you may be getting an invisibly=20 small spark connecting the can to the chain in the tank. The spark=20 would have to be at just the right place to get a fuel-air mixture to=20 ignite, so chances of bad things happening are extremely low. But such=20 an easily remediated exposure. Get an ESD wrist strap from RadioShack or other electronic supplier. =20 For those who don't know, these are bungee straps woven with a=20 conductive (carbon?) fiber. They have a clip which connects to a coiled=20 wire lead, terminated by an alligator clip. The wire has a large value=20 resistor in it. You attach the alligator clip to what you want to be=20 grounded to, and then the static potential energy drains through the=20 wire. The difference from just letting a chain contact is that the=20 charge drains at a controlled rate. It is slow enough to eliminate the=20 spark. Get a metal can and cinch one of these straps around the neck onto=20 exposed metal. Now you have your grounding wire that will extend and=20 collapse like a telephone cord, and eliminates one more avenue of disaster. --=20 http://www.ernest.isa-geek.org -- Homepage: http://www.flyrotary.com/ Archive and UnSub: http://mail.lancaironline.net:81/lists/flyrotary/List.= html