Return-Path: Received: from [24.25.9.102] (HELO ms-smtp-03-eri0.southeast.rr.com) by logan.com (CommuniGate Pro SMTP 4.1.8) with ESMTP id 2997119 for flyrotary@lancaironline.net; Wed, 18 Feb 2004 09:48:39 -0500 Received: from edward (clt78-020.carolina.rr.com [24.93.78.20]) by ms-smtp-03-eri0.southeast.rr.com (8.12.10/8.12.7) with SMTP id i1IEmZaC004571 for ; Wed, 18 Feb 2004 09:48:37 -0500 (EST) Message-ID: <002b01c3f62e$4c3b0250$2402a8c0@edward> From: "Ed Anderson" To: "Rotary motors in aircraft" References: Subject: Re: [FlyRotary] fuel pumps Date: Wed, 18 Feb 2004 09:48:39 -0500 MIME-Version: 1.0 Content-Type: text/plain; charset="Windows-1252" Content-Transfer-Encoding: 7bit X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook Express 6.00.2800.1158 X-MIMEOLE: Produced By Microsoft MimeOLE V6.00.2800.1165 X-Virus-Scanned: Symantec AntiVirus Scan Engine Paul, As you have seen, the recommendation is two fuel pumps. One fuel pump even with a "lifetime" warranty and guaranteed never to "wear out" is not a good bet. First, all that guarantee really means is the manufacture believes that he will acquire more profit in additional sales with the "lifetime" warranty than it will cost him to honor "failure returns". It tells you absolutely nothing about the inherent design and material reliability of the product itself. Guaranteed never to "wear out" is also not the same as "guaranteed not to fail". I believe you can only count on products that have a favorable history of failure in use. Even prolong manufacture tests frequently fail to duplicate the real world failure rates. The evaluation criteria in my mind is - what is the cost to ensure redundancy in a critical system Vs the potential down side if that component fails. I need not tell you the down side of a single fuel pump failing. I designed my fuel feed with two independent feeds from my header tank to each of my two fuel pumps. Then each pump has its own high pressure filter - I recommend a separate filter for each pump - if you have both feeding the same filter and the filter plugs up, well, you can figure the rest. I then use a "Y" to bring the two high pressure fuel lines together going to the fuel rails. Regarding activation. The simplest thing might be to have your CPU system control your primary pump through its relay and simple use a manual toggle switch to turn on the secondary pump. I only have my secondary pump on for take off and landing and its not hard to put a reminder in your check list to turn on the secondary pump for those phases of flight. The MSD fuel pumps and the models Tracy Crook sells will put out approx. 80 psi with no flow and no regulator. So you do need a regulator to stabilize your fuel pressure at around 43 psi for good consistent fuel injection. my 0.02 worth Ed Ed Anderson RV-6A N494BW Rotary Powered Matthews, NC ----- Original Message ----- From: "sqpilot@earthlink" To: "Rotary motors in aircraft" Sent: Tuesday, February 17, 2004 7:38 PM Subject: [FlyRotary] fuel pumps > I am nearing the end of my 13b engine installaon...Are most of you using two > fuel pumps, or do you feel that the pumps are reliable enough to run only > one? I have the MSD fuel pump. Also, I assume that most high pressure fuel > pumps (45psi) can be mounted either vertically or horizontally? Thanks for > any and all suggestions. Paul Conner, 13b powered SQ2000 > > > > >> Homepage: http://www.flyrotary.com/ > >> Archive: http://lancaironline.net/lists/flyrotary/List.html >