X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Sender: To: lml@lancaironline.net Date: Wed, 19 Apr 2006 23:00:08 -0400 Message-ID: X-Original-Return-Path: Received: from web34906.mail.mud.yahoo.com ([209.191.68.185] verified) by logan.com (CommuniGate Pro SMTP 5.0.9) with SMTP id 1073475 for lml@lancaironline.net; Wed, 19 Apr 2006 15:04:27 -0400 Received-SPF: none receiver=logan.com; client-ip=209.191.68.185; envelope-from=n103md@yahoo.com Received: (qmail 81140 invoked by uid 60001); 19 Apr 2006 19:03:41 -0000 DomainKey-Signature: a=rsa-sha1; q=dns; c=nofws; s=s1024; d=yahoo.com; h=Message-ID:Received:Date:From:Subject:To:MIME-Version:Content-Type:Content-Transfer-Encoding; b=LpJcDPcTqjjS4PY2s+D7eX38qrqbszBns/AhjRbktzbe6ZCTDMrxER/chQAp5RDOLTksbw/8+NnESqGhFm7T0GOUF66nUlqU8Ze8lRq+ioMS67zpUEQOgdA4Nuzgc5yKIJdZkC3k4ZZwbNnvfQjMTr/nWpTn9Bntds6R/BDHzeI= ; X-Original-Message-ID: <20060419190341.81138.qmail@web34906.mail.mud.yahoo.com> Received: from [12.146.139.19] by web34906.mail.mud.yahoo.com via HTTP; Wed, 19 Apr 2006 12:03:41 PDT X-Original-Date: Wed, 19 Apr 2006 12:03:41 -0700 (PDT) From: bob mackey Subject: Re: Fuel Transfer X-Original-To: lml@lancaironline.net MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="0-1195295964-1145473421=:81136" Content-Transfer-Encoding: 8bit --0-1195295964-1145473421=:81136 Content-Type: text/plain; charset=iso-8859-1 Content-Transfer-Encoding: 8bit Scott suggested that a crossover valve allows the fuel in both wings to be pumped to the header if one Facet pump fails. That's almost true. When the crossover valve is open, the pump draws from both sides. When one side sucks air, it provides the lower pressure drop in the line and the pump sucks mostly air. The pumping rate of fuel goes way down. This is the way my present fuel system works. It will be changed. Having redundant pumps and plumbing doesn't give access to the wing fuel in the event of an electrical failure. To answer that situation, my fuel system has a valve to select either wings or header. When "wings" is selected, the fuel is drawn from a small sump between the two wings. There is one pump from there to the header which sucks air as described above. -bob --------------------------------- Love cheap thrills? Enjoy PC-to-Phone calls to 30+ countries for just 2¢/min with Yahoo! Messenger with Voice. --0-1195295964-1145473421=:81136 Content-Type: text/html; charset=iso-8859-1 Content-Transfer-Encoding: 8bit Scott suggested that a crossover valve allows the fuel in both wings
to be pumped to the header if one Facet pump fails. That's almost true.
When the crossover valve is open, the pump draws from both sides.
When one side sucks air, it provides the lower pressure drop in the line
and the pump sucks mostly air. The pumping rate of fuel goes way down.
This is the way my present fuel system works. It will be changed.


Having redundant pumps and plumbing doesn't give access to the
wing fuel in the event of an electrical failure. To answer that situation,
my fuel system has a valve to select either wings or header. When "wings"
is selected, the fuel is drawn from a small sump between the two wings.
There is one pump from there to the header which sucks air as described
above.

-bob




Love cheap thrills? Enjoy PC-to-Phone calls to 30+ countries for just 2¢/min with Yahoo! Messenger with Voice. --0-1195295964-1145473421=:81136--