Return-Path: Received: from relay02.roc.ny.frontiernet.net ([66.133.182.165] verified) by logan.com (CommuniGate Pro SMTP 4.3c1) with ESMTP id 741067 for flyrotary@lancaironline.net; Wed, 16 Feb 2005 01:14:55 -0500 Received-SPF: pass receiver=logan.com; client-ip=66.133.182.165; envelope-from=canarder@frontiernet.net Received: from filter10.roc.ny.frontiernet.net (filter10.roc.ny.frontiernet.net [66.133.183.77]) by relay02.roc.ny.frontiernet.net (Postfix) with ESMTP id 5CFFE370455 for ; Wed, 16 Feb 2005 06:14:09 +0000 (UTC) Received: from relay02.roc.ny.frontiernet.net ([66.133.182.165]) by filter10.roc.ny.frontiernet.net (filter10.roc.ny.frontiernet.net [66.133.183.77]) (amavisd-new, port 10024) with LMTP id 32172-21-5 for ; Wed, 16 Feb 2005 06:14:09 +0000 (UTC) Received: from [127.0.0.1] (67-137-75-55.dsl2.cok.tn.frontiernet.net [67.137.75.55]) by relay02.roc.ny.frontiernet.net (Postfix) with ESMTP id 91BFD37030D for ; Wed, 16 Feb 2005 06:14:07 +0000 (UTC) Message-ID: <4212E4AA.5030007@frontiernet.net> Date: Wed, 16 Feb 2005 00:14:02 -0600 From: Jim Sower User-Agent: Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.7) Gecko/20040514 X-Accept-Language: en-us, en MIME-Version: 1.0 To: Rotary motors in aircraft Subject: Re: [FlyRotary] Re: Fuel System Design - Jet Pump References: In-Reply-To: Content-Type: multipart/alternative; boundary="------------020600000607080700060609" X-Antivirus: avast! (VPS 0507-0, 02/15/2005), Outbound message X-Antivirus-Status: Clean X-Virus-Scanned: by amavisd-new-20040701 (2.0) at filter10.roc.ny.frontiernet.net This is a multi-part message in MIME format. --------------020600000607080700060609 Content-Type: text/plain; charset=us-ascii; format=flowed Content-Transfer-Encoding: 7bit <... you'd want two lines. One from the bottom of B to the jet pump. Another from the mid level of A to the top of B ... A full B empty... B full A empty ... A & B half full ... A & B full ... parked on a hill ... > Sounds a lot like a ten-cent tail wagging a forty-dollar dog here. Didn't we set out to *simplify* something? How about just ONE line from B to A with a Facet pump. To get fancy, you could have a momentary ON for the pump that would cause it to pump for 2 or 3 min or something and then turn itself off. Just trying to stay on message ... Jim S. PS Has anyone actually *seen* the two-line-jet-pump and watched it actually WORK ?? (the devil made me say that ) Ernest Christley wrote: > >> >> >> Thoughts on the jet pump: >> <> >> >> Fuel tank levels needs to be controlled in order to eliminate a >> 'heavy wing' which is very fatiguing on a long cross country. >> Aileron trim can do it but that adds drag. A valve can be used but >> that adds to the complexity again. >> >> Tracy >> > > Looking over the diagram in the PDF that Ed sent. The jet pump works > all the time, constantly pumping fuel from the bottom of B into A, > where the main pump can pick it up. An important element to this is > that there is a large return path for fuel to go from A to B. If the > tank is half full or more, all the fuel moved by the jet pump just > flows back over. > > In the airplane transfer, you'd want two lines. One from the bottom > of B to the jet pump. Another from the mid level of A to the top of > B. The lines need to stay below the tanks. At no point will the the > sides ever be more than 1/2 a tank different. Consider: > > A is full, B is empty > Fuel will flow from A to B via the return line, until A is half empty. > B is full, A is empty > Fuel will flow to A via the jet pump, until B is empty. > A and B are both half full > Fuel will flow to A. If A gets more than half full, fuel will flow > back to B. > A and B are both full, and you park sideways on a hill. > Fuel will flow to the ground until the high tank is empty. Doh!! > > >>> Homepage: http://www.flyrotary.com/ >>> Archive: http://lancaironline.net/lists/flyrotary/List.html >> > > --------------020600000607080700060609 Content-Type: text/html; charset=us-ascii Content-Transfer-Encoding: 7bit <... you'd want two lines.  One from the bottom of B to the jet pump.  Another from the mid level of A to the top of B ... A full B empty... B full A empty ... A & B half full ... A & B full ... parked on a hill ... >
Sounds a lot like a ten-cent tail wagging a forty-dollar dog here.  Didn't we set out to simplify something?  How about just ONE line from B to A with a Facet pump.  To get fancy, you could have a momentary ON for the pump that would cause it to pump for 2 or 3 min or something and then turn itself off. 

Just trying to stay on message ... Jim S.

PS  Has anyone actually seen the two-line-jet-pump and watched it actually WORK ??
(the devil made me say that )


Ernest Christley wrote:



Thoughts on the jet pump:
<>

Fuel tank levels needs to be controlled in order to eliminate a 'heavy wing' which is very fatiguing on a long cross country.  Aileron trim can do it but that adds drag.  A valve can be used but that adds to the complexity again.

Tracy


Looking over the diagram in the PDF that Ed sent.  The jet pump works all the time, constantly pumping fuel from the bottom of B into A, where the main pump can pick it up.  An important element to this is that there is a large return path for fuel to go from A to B.  If the tank is half full or more, all the fuel moved by the jet pump just flows back over.

In the airplane transfer, you'd want two lines.  One from the bottom of B to the jet pump.  Another from the mid level of A to the top of B.  The lines need to stay below the tanks.  At no point will the the sides ever be more than 1/2 a tank different.  Consider:

A is full, B is empty
   Fuel will flow from A to B via the return line, until A is half empty.
B is full, A is empty
   Fuel will flow to A via the jet pump, until B is empty.
A and B are both half full
   Fuel will flow to A.  If A gets more than half full, fuel will flow back to B.
A and B are both full, and you park sideways on a hill.
   Fuel will flow to the ground until the high tank is empty. Doh!!


 Homepage:  http://www.flyrotary.com/
 Archive:   http://lancaironline.net/lists/flyrotary/List.html


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