X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Received: from [24.25.9.102] (HELO ms-smtp-03-eri0.southeast.rr.com) by logan.com (CommuniGate Pro SMTP 4.3c5) with ESMTP id 922096 for flyrotary@lancaironline.net; Mon, 02 May 2005 09:23:39 -0400 Received-SPF: pass receiver=logan.com; client-ip=24.25.9.102; envelope-from=eanderson@carolina.rr.com Received: from edward2 (cpe-024-074-189-178.carolina.res.rr.com [24.74.189.178]) by ms-smtp-03-eri0.southeast.rr.com (8.12.10/8.12.7) with SMTP id j42DMpY5006537 for ; Mon, 2 May 2005 09:22:52 -0400 (EDT) Message-ID: <007b01c54f1a$0b4432d0$2402a8c0@edward2> From: "Ed Anderson" To: "Rotary motors in aircraft" References: Subject: Re: [FlyRotary] Re: fuel pumps/forced landing Date: Mon, 2 May 2005 09:22:52 -0400 MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_0078_01C54EF8.83FE1550" X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook Express 6.00.2900.2180 X-MIMEOLE: Produced By Microsoft MimeOLE V6.00.2900.2180 X-Virus-Scanned: Symantec AntiVirus Scan Engine This is a multi-part message in MIME format. ------=_NextPart_000_0078_01C54EF8.83FE1550 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Probably not Dave, The first fuel injection system I flew with was an after market HALTECH = unit. It had a similar arrangement to the MicroTech (and is also made = in Australia) , if no ignition signal was detected after 2 seconds or = so, it would open the relay providing power to the fuel pump. True you = could have a pressure sensor in the fuel line although I have not yet = heard of a unit with one there (I think expense of the sensor is = probably one reason). However, another similar approach to the one you = suggested that I have seen used - is to use a pressure sensor in the = engine oil lubrication system. If no oil pressure within a set time = implies the engine did not start and the relay will open cutting of = power to the fuel pump. Ed ----- Original Message -----=20 From: David Staten=20 To: Rotary motors in aircraft=20 Sent: Monday, May 02, 2005 8:53 AM Subject: [FlyRotary] Re: fuel pumps/forced landing The"ignition" system is shutting off the pump once adequate head = pressure is obtained. Its not the engine starting that directly triggers = the pump. Its the engine using the fuel in the rail, lowering the = pressure below the triggering threshold on some pressure sensor = somewhere, causing a logic circuit to turn the pump back on. The = feedback loop in this situation is based on fuel pressure. =20 Dave William wrote: Paul, If your ignition system shuts off the pump with no spark, isn't the = following going to happen? Pump 1 on -- engine running, pump 1 fuse blows, engine shuts down very quickly, Pump 2 turned on, but no spark since engine has stopped, therefore = it shuts off right away. Sounds like if engine stops, you have to crank it to get it started = again Bill Schertz KIS Cruiser # 4045 ----- Original Message -----=20 From: sqpilot@bellsouth.net=20 To: Rotary motors in aircraft=20 Sent: Monday, May 02, 2005 1:42 PM Subject: [FlyRotary] Re: fuel pumps/forced landing Turned on the other pump, but the engine had already quit. (yes, = it happens very fast) =20 I now recall reading in the MicroTech manual that the fuel = pumps shut off if it detects no spark from the coils, so that it would = not continue pumping fuel into an engine that has no spark. This is = obviously why the pump only runs for a few seconds when I first turn on = the ignition switch, then quickly stops pumping. We put a voltmeter to = the inline fuse, and found that it had 12.9 volts as soon as the = ignition was turned on, but after a few seconds, the pump stopped and = there was no longer any voltage at the fuse.=20 I'm hoping we can find what caused the slight fuel obstruction = in front of the gascolator....if we can't find the cause, it would be = difficult to regain confidence in the fuel system. Too bad, because the = engine was running strong and smooth, and the temps were great!!! Paul = aka deadstick Conner >> Homepage: http://www.flyrotary.com/ >> Archive: http://lancaironline.net/lists/flyrotary/List.html ------=_NextPart_000_0078_01C54EF8.83FE1550 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable
Probably not Dave,
 
The first fuel injection system I flew = with was an=20 after market HALTECH unit.  It had a similar arrangement to = the=20 MicroTech (and is also made in Australia) , if no ignition signal was = detected=20 after 2 seconds or so, it would open the relay providing power to the = fuel=20 pump.  True you could have a pressure sensor in the fuel line = although I=20 have not yet heard of a unit with one there (I think expense = of the=20 sensor is probably one reason).  However, another similar approach = to the=20 one you suggested   that I have seen used - is to = use a=20 pressure sensor in the engine oil lubrication system.  If no oil = pressure=20 within a set time implies the engine did not start and the relay will = open=20 cutting of power to the fuel pump.
 
Ed
 
 
----- Original Message -----
From:=20 David=20 Staten
Sent: Monday, May 02, 2005 8:53 = AM
Subject: [FlyRotary] Re: fuel=20 pumps/forced landing

The"ignition" system is shutting off the pump once = adequate=20 head pressure is obtained. Its not the engine starting that directly = triggers=20 the pump. Its the engine using the fuel in the rail, lowering the = pressure=20 below the triggering threshold on some pressure sensor somewhere, = causing a=20 logic circuit to turn the pump back on. The feedback loop in this = situation is=20 based on fuel pressure.
 
Dave

William wrote:
Paul,
If your ignition system shuts off = the pump with=20 no spark, isn't the following going to happen?
 
Pump 1 on -- engine = running,
pump 1 fuse blows, engine shuts = down very=20 quickly,
Pump 2 turned on, but no spark = since engine has=20 stopped, therefore it shuts off right away.
 
Sounds like if engine stops, you = have to crank=20 it to get it started again
Bill Schertz
KIS Cruiser # 4045
-----=20 Original Message ----- From:=20 sqpilot@bellsouth.net = To:=20 Rotary motors in = aircraft=20 Sent:=20 Monday, May 02, 2005 1:42 PM Subject:=20 [FlyRotary] Re: fuel pumps/forced landing
 Turned on the other pump, = but=20 the engine had already quit. (yes, it happens very=20 fast)  
 
      I = now recall=20 reading in the MicroTech manual that the fuel pumps shut off if it = detects=20 no spark from the coils, so that it would not continue pumping = fuel into=20 an engine that has no spark. This is obviously why the pump only = runs for=20 a few seconds when I first turn on the ignition switch, then = quickly stops=20 pumping. We put a voltmeter to the inline fuse, and found that it = had 12.9=20 volts as soon as the ignition was turned on, but after a few = seconds, the=20 pump stopped and there was no longer any voltage at the fuse.=20
    I'm hoping we = can find=20 what caused the slight fuel obstruction in front of the = gascolator....if=20 we can't find the cause, it would be difficult to regain = confidence in the=20 fuel system. Too bad, because the engine was running strong and = smooth,=20 and the temps were great!!!  Paul aka deadstick=20 Conner

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