X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Received: from zixvpm1.fdic.gov ([167.176.6.41] verified) by logan.com (CommuniGate Pro SMTP 5.4c2o) with ESMTPS id 4882878 for flyrotary@lancaironline.net; Fri, 25 Feb 2011 16:29:24 -0500 Received-SPF: pass receiver=logan.com; client-ip=167.176.6.41; envelope-from=brogers@fdic.gov Received: from zixvpm1.fdic.gov (ZixVPM [127.0.0.1]) by Outbound.fdic.gov (Proprietary) with ESMTP id 2AB4C940714 for ; Fri, 25 Feb 2011 16:28:49 -0500 (EST) Received: from mail.fdic.gov (unknown [10.30.1.9]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by zixvpm1.fdic.gov (Proprietary) with ESMTP id AA6F09406FF for ; Fri, 25 Feb 2011 16:28:48 -0500 (EST) Received: from VASWEXC101P.PROD.FDIC.GOV (exchange1 [172.25.160.60]) by mail.fdic.gov (Sentrion-MTA-4.1.1/Sentrion-MTA-4.1.1) with ESMTP id p1PLSlqI013041 for ; Fri, 25 Feb 2011 16:28:48 -0500 X-MimeOLE: Produced By Microsoft Exchange V6.5 Content-class: urn:content-classes:message MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----_=_NextPart_001_01CBD532.FC574550" Subject: RE: [FlyRotary] Fuel return line Date: Fri, 25 Feb 2011 15:28:47 -0600 Message-ID: <1F44A251F397E444B05E240B8688AB79097CA019@DALEXC100P.PROD.FDIC.GOV> In-Reply-To: X-MS-Has-Attach: X-MS-TNEF-Correlator: Thread-Topic: [FlyRotary] Fuel return line Thread-Index: AcvVKWcK3subLIOiQTWi2Zv5RChvIgAB/4bw References: From: "Rogers, Bob J." To: "Rotary motors in aircraft" X-OriginalArrivalTime: 25 Feb 2011 21:28:47.0172 (UTC) FILETIME=[FC831040:01CBD532] This is a multi-part message in MIME format. ------_=_NextPart_001_01CBD532.FC574550 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Raymond, =20 For a high-pressure fuel pump that generates a large volume of fuel = flow, a 1/4" return line seems a bit small to me. If you attach a fuel = pressure gauge to a "T" midway in the =BC" return line and run fuel = through your pump and out the return line (past the pressure gauge), = when the return line is big enough to handle the flow, then you will see = almost no build up in pressure. If the line is too small, then the = inability of the fuel to easily escape through the return line will = cause a build-up of pressure in the gauge. The amount may be negligible = or it may be a lot, depending on the force of the fuel. Ideally, the = pressure on the return line would be zero, or close to it. Use a return = line that generates little or no pressure on the fuel pump. =20 Bob =20 ________________________________ From: Rotary motors in aircraft [mailto:flyrotary@lancaironline.net] On = Behalf Of Raymond Lambert Sent: Friday, February 25, 2011 2:20 PM To: Rotary motors in aircraft Subject: [FlyRotary] Fuel return line =20 I am about to put the fuel tank in my first wing. I have to weld a = flange on it for the fuel return line. Anyone can tell me if a 1/4" fuel = return line is large enough ???? Raymond ------_=_NextPart_001_01CBD532.FC574550 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable

Raymond,

 

For a high-pressure fuel pump that generates a large volume of fuel flow, a 1/4“ return line seems a = bit small to me.=A0 If you attach a = fuel pressure gauge to a “T” midway in the =BC” return line and run = fuel through your pump and out the return line (past the pressure gauge), = when the return line is big enough to handle the flow, then you will see almost = no build up in pressure.=A0 If the line = is too small, then the inability of the fuel to easily escape through the = return line will cause a build-up of pressure in the gauge.=A0 The amount may be negligible or it may be a lot, depending on the = force of the fuel.=A0 Ideally, the = pressure on the return line would be zero, or close to it.=A0 Use a return line that generates little or no pressure on the = fuel pump.

 

Bob

 

From: Rotary motors in = aircraft [mailto:flyrotary@lancaironline.net] On Behalf Of Raymond Lambert
Sent: Friday, February = 25, 2011 2:20 PM
To: Rotary motors in aircraft
Subject: [FlyRotary] Fuel = return line

 

I am about to put = the fuel tank in my first wing. I have to weld a flange on it for the fuel = return line. Anyone can tell me if a 1/4" fuel return line is large enough = ????

Raymond

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