X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Received: from aspensprings.uwyo.edu ([129.72.10.32] verified) by logan.com (CommuniGate Pro SMTP 6.0c3) with ESMTPS id 5929802 for flyrotary@lancaironline.net; Sat, 08 Dec 2012 16:53:07 -0500 Received-SPF: none receiver=logan.com; client-ip=129.72.10.32; envelope-from=SBoese@uwyo.edu Received: from ponyexpress-ht3.uwyo.edu (extlb.uwyo.edu [172.26.4.4]) by aspensprings.uwyo.edu (8.14.4/8.14.4) with ESMTP id qB8LqT9K025521 (version=TLSv1/SSLv3 cipher=AES128-SHA bits=128 verify=FAIL) for ; Sat, 8 Dec 2012 14:52:29 -0700 (MST) (envelope-from SBoese@uwyo.edu) Received: from ponyexpress-m10.uwyo.edu ([fe80::60dd:cb9e:6f71:3d48]) by ponyexpress-ht3.uwyo.edu ([fe80::4cde:db24:a0a9:ba5%15]) with mapi id 14.02.0318.001; Sat, 8 Dec 2012 14:52:29 -0700 From: "Steven W. Boese" To: Rotary motors in aircraft Subject: RE: [FlyRotary] Re: Aeroquip hose Thread-Topic: [FlyRotary] Re: Aeroquip hose Thread-Index: AQHN1YRl+VBvakUlqEC/qcYUAiuVMpgPZ4Ix Date: Sat, 8 Dec 2012 21:52:28 +0000 Message-ID: <3E8191F276108F4481AB0721BBA9269E05EC6325@ponyexpress-m10.uwyo.edu> References: In-Reply-To: Accept-Language: en-US Content-Language: en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: x-originating-ip: [75.220.40.238] Content-Type: multipart/alternative; boundary="_000_3E8191F276108F4481AB0721BBA9269E05EC6325ponyexpressm10u_" MIME-Version: 1.0 --_000_3E8191F276108F4481AB0721BBA9269E05EC6325ponyexpressm10u_ Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Bill, From your description, your ground architecture sounds very similar to mine= . I have the forest of tabs bolted to the firewall with a brass bolt. On = the cabin side, the battery ground is connected to this bolt. Everything e= lse grounds to the forest of tabs. On the engine side of the firewall, the= engine ground is connected from the front (in the car) cover to that brass= bolt. My arrangement has not had any electrical problems that I am aware = of. I also have a stainless wire braid covered fuel line from the firewall bulk= head fitting to the fuel rail on the engine. I have seen no damage to it. = The fact that your wire braid on the fuel line has been burnt suggests tha= t it might have intermittently served as the engine ground at one time or a= nother. The braid must not have conducted a large current for very long or= it would been destroyed completely. I can't think of a worse place to hav= e an uncontrolled resistance heater than on that fuel line. Verifying the = integrity of the ground from the engine to the airframe and from the batter= y to the airframe certainly seems like a worthwhile endeavor. Depending on the details of the alternator installation, an intermittent co= nnection inside the battery also might be a possibility although this would= not explain the damage to the fuel line braid. FWIW Steve Boese RV6A, 1986 13B NA, RD1A, EC2 --_000_3E8191F276108F4481AB0721BBA9269E05EC6325ponyexpressm10u_ Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable

Bill,

 

From your description, your ground architecture sounds very similar= to mine.  I have the forest of tabs bolted to the firewall with = a brass bolt.  On the cabin side, the battery ground is connected to t= his bolt.  Everything else grounds to the forest of tabs.  On the engine side of the firewall, the engine ground is conne= cted from the front (in the car) cover to that brass bolt. &= nbsp;My arrangement has not had any electrical problems that I am aware of.=

 

I also have a stainless wire braid covered fuel line from the firewall b= ulkhead fitting to the fuel rail on the engine.  I have seen no damage= to it.  The fact that your wire braid on the fuel line has been burnt= suggests that it might have intermittently served as the engine ground at one time or another.  The braid must n= ot have conducted a large current for very long or it would been destroyed = completely.  I can't think of a worse place to have an uncontrolled re= sistance heater than on that fuel line.  Verifying the integrity of the ground from the engine to the airframe and from the b= attery to the airframe certainly seems like a worthwhile endeav= or.

 

Depending on the details of the alternator installation, an intermittent= connection inside the battery also might be a possibility although this wo= uld not explain the damage to the fuel line braid.

 

FWIW

 

Steve Boese
RV6A, 1986 13B NA, RD1A, EC2

        

 

 

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