X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Sender: To: lml@lancaironline.net Date: Thu, 14 Jun 2007 14:32:51 -0400 Message-ID: X-Original-Return-Path: Received: from [68.98.211.24] (HELO systems3.net) by logan.com (CommuniGate Pro SMTP 5.1.9) with ESMTP id 2102729 for lml@lancaironline.net; Thu, 14 Jun 2007 14:12:53 -0400 Received-SPF: none receiver=logan.com; client-ip=68.98.211.24; envelope-from=cberland@systems3.net Content-class: urn:content-classes:message MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----_=_NextPart_001_01C7AEAF.89FA74F0" X-MimeOLE: Produced By Microsoft Exchange V6.5 Subject: [LML] Re: Boost Pump X-Original-Date: Thu, 14 Jun 2007 11:12:18 -0700 X-Original-Message-ID: <87C33F695961494D886EB3B6C8A476512F3A16@s3server.Systems3.local> X-MS-Has-Attach: X-MS-TNEF-Correlator: Thread-Topic: [LML] Re: Boost Pump Thread-Index: Aceuo2mVtCoEcvw9SHC84WKdhl8XswACaLNQ From: "Craig Berland" X-Original-To: "Lancair Mail List" This is a multi-part message in MIME format. ------_=_NextPart_001_01C7AEAF.89FA74F0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: quoted-printable I'm sorry but I have too many irons in the fire for much of a detailed response.=20 Craig said,=20 There is a variable orifice as well as the bypass valve involved in the fuel return system that will affect fuel rate beyond the return line size =20 Craig,=20 can you say a little more about these features? What is a variable orifice? Off deck pressure via the aneroid. (piston and orifice) Where is it in relation to the boost pump, eng pump, metering unit? All of these features are built into the engine driven fuel pump. The engine fuel pump controls the pressure going to the metering unit. The boost pump is upstream to the engine pump and the metering unit is downstream of the engine pump. Where is the bypass and what does it take to open it? The bypass is in the engine pump. I'm not sure how this all interacts. There is also a recirculation path going back to the vapor separator. The recirculation path is blocked at full rich and fuel flow should be blocked at idle cut off. Not one thing controls the bypass fuel. =20 This may be more confusing than helpful. Hopefully someone will correct me if I have made a mistake in my haste. Craig Panel done is 2 weeks 1st flight is getting close =20 thanks, =20 Colyn ------_=_NextPart_001_01C7AEAF.89FA74F0 Content-Type: text/html; charset="us-ascii" Content-Transfer-Encoding: quoted-printable
I'm sorry but I have too many irons in = the fire=20 for much of a detailed response.
Craig said, =
There is a variable orifice as well as the bypass valve = involved in=20 the fuel return system that will affect fuel rate beyond the return line = size
 
Craig, =
can = you say a little=20 more about these features?
What is a=20 variable  orifice?   Off deck pressure via the = aneroid. (piston=20 and orifice)
Where is it in=20 relation to the boost pump, eng pump, metering unit?  All of these = features are=20 built into the engine driven fuel pump.  The engine fuel pump = controls the=20 pressure going to the metering unit.  The boost pump = is upstream to=20 the engine pump and the metering unit is downstream of the engine=20 pump.
Where is the=20 bypass and what does it take to open it?  The bypass is in the engine pump. I'm not = sure how=20 this all interacts. There is also a recirculation path going back to the = vapor=20 separator. The recirculation path is blocked at full rich and fuel flow = should=20 be blocked at idle cut off.  Not one thing controls the bypass=20 fuel.
 
This may be more confusing = than=20 helpful.  Hopefully someone will correct me if I have made a = mistake in my=20 haste.
Craig
Panel done is 2=20 weeks
1st flight is getting=20 close
 
thanks,
 
Colyn
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