Return-Path: Received: from fep04-mail.bloor.is.net.cable.rogers.com ([66.185.86.74] verified) by logan.com (CommuniGate Pro SMTP 4.1.8) with ESMTP id 2989707 for flyrotary@lancaironline.net; Thu, 12 Feb 2004 19:22:34 -0500 Received: from CR754193A ([24.43.221.42]) by fep04-mail.bloor.is.net.cable.rogers.com (InterMail vM.5.01.05.12 201-253-122-126-112-20020820) with ESMTP id <20040213002226.KAIY322971.fep04-mail.bloor.is.net.cable.rogers.com@CR754193A> for ; Thu, 12 Feb 2004 19:22:26 -0500 From: "Neil Kruiswyk" To: "'Rotary motors in aircraft'" Subject: RE: [FlyRotary] Re: EFI Fuel Pressure Date: Thu, 12 Feb 2004 19:22:58 -0500 Message-ID: <000901c3f1c7$886ebb10$6402a8c0@CR754193A> MIME-Version: 1.0 Content-Type: text/plain; charset="US-ASCII" Content-Transfer-Encoding: 7bit X-Priority: 3 (Normal) X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook, Build 10.0.2616 Importance: Normal In-Reply-To: X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2800.1165 X-Authentication-Info: Submitted using SMTP AUTH LOGIN at fep04-mail.bloor.is.net.cable.rogers.com from [24.43.221.42] using ID at Thu, 12 Feb 2004 19:22:26 -0500 Bob is right, I calculated total pressure in a 3/8th line and not PSI. (Grade 11 was a LONG tine ago) Neil -----Original Message----- From: Rotary motors in aircraft [mailto:flyrotary@lancaironline.net] On Behalf Of Bob Darrah Sent: February 12, 2004 7:17 PM To: Rotary motors in aircraft Subject: [FlyRotary] Re: EFI Fuel Pressure ----- Original Message ----- From: "Neil Kruiswyk" To: "Rotary motors in aircraft" Sent: Thursday, February 12, 2004 5:57 PM Subject: [FlyRotary] Re: EFI Fuel Pressure > Scott, > > You're only dealing with a column of fuel 40" high and not the > weight of all 5 gallons. Assuming the return line is 3/8th inch ID > (which would be on the big side), 40 inches works out to a grand total > of 4.4 cubic inches of fuel, or, a grand total of .11 lbs/sq in. > > (Did I remember my grade 11 math correctly?) Close, but no cegar! The 40 inch high collum is all that counts. Makes no difference if it's a 3/8" line or 3" line. The pressure at the bottom of the colum would be just under 2 psi. But the column that applies here is how high above the pressure regulator does the return fuel have to go. If you plum it to the top of the tank, it will have to lift the fuel that high always-very consistent. If you plum it to the middle or even the bottom of the tank, it only has to pump it to the existing fuel level. Sure, it will very but only by the pressure differential of the vertical height of the tank at the rate of about 25 inches per psi. Bob Darrah >> Homepage: http://www.flyrotary.com/ >> Archive: http://lancaironline.net/lists/flyrotary/List.html