Return-Path: Received: from fed1mtao02.cox.net ([68.6.19.243] verified) by logan.com (CommuniGate Pro SMTP 4.1.8) with ESMTP id 3084144 for flyrotary@lancaironline.net; Thu, 18 Mar 2004 00:25:30 -0500 Received: from BigAl ([68.107.116.221]) by fed1mtao02.cox.net (InterMail vM.5.01.06.08 201-253-122-130-108-20031117) with ESMTP id <20040318052528.XKMK16948.fed1mtao02.cox.net@BigAl> for ; Thu, 18 Mar 2004 00:25:28 -0500 From: "Al Gietzen" To: "'Rotary motors in aircraft'" Subject: Backup fuel pump Date: Wed, 17 Mar 2004 21:25:43 -0800 Message-ID: <000001c40ca9$75d1b320$6400a8c0@BigAl> MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_0001_01C40C66.67AE7320" X-Priority: 3 (Normal) X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook, Build 10.0.4024 Importance: Normal In-Reply-To: X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2800.1165 This is a multi-part message in MIME format. ------=_NextPart_000_0001_01C40C66.67AE7320 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit -----Original Message----- From: Rotary motors in aircraft [mailto:flyrotary@lancaironline.net] On Behalf Of Jim Sower Sent: Wednesday, March 17, 2004 8:27 AM To: Rotary motors in aircraft Subject: [FlyRotary] Re: mainfold hose <... Do you suppose that this wouldn't react fast enough to keep the engine running? ...> Even if you didn't have the automatic switchover, I bet YOU would react fast enough so the prop would never stop. What I wonder about is with auto changeover, how do you know the primary pump failed? I wouldn't. I'd only know that the pressure went too low. Light on panel shows backup pump running. And how would you be able to shut down the engine by turning off the pump The backup pump has an "enable" switch (enables auto switch-on) and "on" switch. Both off means pump is off. ? I assume that if the auto changeover fails, you can still turn on the backup manually. Yep . Al Al Gietzen wrote: Perry wrote: If you are flying and running only one h.p. fuel pump, and that pump fails, the engine will become silent only milliseconds later! This is interesting. As my circuit diagram is currently configured, I have a pressure switch in the fuel system which automatically turns on the backup pump if the pressure drops below about 30 psi. (don't remember now the exact setting on the pressure switch). Do you suppose that this wouldn't react fast enough to keep the engine running? There is a manual bypass so I can turn the pump on if I want. The idea was to turn on both pumps for takeoff, but at other times the backup would automatically kick in to keep the engine from stopping if the primary pump stopped; thereby avoiding rapid heart rates on the part of pilot and passengers. ------=_NextPart_000_0001_01C40C66.67AE7320 Content-Type: text/html; charset="us-ascii" Content-Transfer-Encoding: quoted-printable

 

 

-----Original = Message-----
From: Rotary motors in = aircraft [mailto:flyrotary@lancaironline.net] On Behalf Of Jim Sower
Sent: Wednesday, March 17, 2004 8:27 = AM
To: Rotary motors in = aircraft
Subject: [FlyRotary] Re: = mainfold hose

 

<... Do you suppose that this = wouldn’t react fast enough to keep the engine running? ...>
Even if you didn't have the automatic switchover, I bet YOU would react = fast enough so the prop would never stop.  What I wonder about is with = auto changeover, how do you know the primary pump failed?

 

I wouldn’t.  I’d = only know that the pressure went too low.  Light on panel shows backup = pump running.

 

  And how would you be able to shut down = the engine by turning off the pump

 

 

The backup pump has an = “enable” switch (enables auto switch-on) and “on” switch.  Both = off means pump is off.


?  I assume that if the auto changeover fails, you can still turn = on the backup manually.

 

Yep .

 

Al

Al Gietzen wrote:

Perry = wrote:

If you are flying and running only one h.p. = fuel pump, and that pump fails, the engine will become silent only milliseconds later! 

This is interesting.  As my circuit diagram is currently configured, I = have a pressure switch in the fuel system which automatically turns on the = backup pump if the pressure drops below about 30 psi. (don’t remember now the = exact setting on the pressure switch).  Do you suppose that this = wouldn’t react fast enough to keep the engine running?

  There is a manual bypass so I can turn the pump on if I want.  The = idea was to turn on both pumps for takeoff, but at other times the backup = would automatically kick in to keep the engine from stopping if the primary = pump stopped; thereby avoiding rapid heart rates on the part of pilot and passengers.
 

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