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Return-Path: Received: from [24.25.9.102] (HELO ms-smtp-03-eri0.southeast.rr.com) by logan.com (CommuniGate Pro SMTP 4.1.8) with ESMTP id 3083439 for flyrotary@lancaironline.net; Wed, 17 Mar 2004 14:39:52 -0500 Received: from edward (clt78-020.carolina.rr.com [24.93.78.20]) by ms-smtp-03-eri0.southeast.rr.com (8.12.10/8.12.7) with SMTP id i2HJdls2012205 for ; Wed, 17 Mar 2004 14:39:49 -0500 (EST) Message-ID: <001701c40c57$9ca4f180$2402a8c0@edward> From: "Ed Anderson" To: "Rotary motors in aircraft" References: Subject: Fuel Pump Master Switch? Date: Wed, 17 Mar 2004 14:39:49 -0500 MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_0014_01C40C2D.B39A9310" X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook Express 6.00.2800.1158 X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2800.1165 X-Virus-Scanned: Symantec AntiVirus Scan Engine This is a multi-part message in MIME format. ------=_NextPart_000_0014_01C40C2D.B39A9310 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Message -----=20 From: Russell Duffy=20 To: Rotary motors in aircraft=20 Sent: Wednesday, March 17, 2004 1:03 PM Subject: [FlyRotary] Re: mainfold hose I was trying to think of a situation where I would want the master = switch on, but not want the fuel pump on. Maybe for an engine = problem/shutdown, but still want to keep the radio and navs on ? =20 =20 Steve=20 That's exactly what I was thinking. I prefer to have both my pumps on = separate switches, but I don't see any fire hazard in regards to leaving = your pump on the master. Like you said, if there's one switch you'll = hit, it's the master. Cheers, Rusty (hope I don't get flamed )=20 =20 No flames Rusty - just fire {:>). =20 If I understand this discussion correctly, I can think of a number of = reasons I might want my master switch on (on the ground) and would not = want the fuel pump running. But, I would presume in that case one could = pull a circuit breaker to disable the fuel pump. I would think you = would hear the pump running - if not (and you canard guys might not) you = might quickly run your battery down with that pump drawing its 5 - 9 = amps with the Master on because you wanted to work on your intercom = wiring,etc. Here's a possible safety issue (may be far feched, but then that's the = ones that get you). You have your pump wired through your master power = switch. You fuel pump malfunctions - say it shorts out and starts to = draw a bunch of amps in that case, unless you have the pump on a circuit = breaker (you do don't you?) , you would be forced to turn off the master = switch - but wait that turns off your engine! Your fuel pressure guage/alarm will give you the first indication of = pump failure. Then as it fall (rather quickly) below a certain level, = the leaning of the mixture will cause the tone of the engine to change = follow shortly by surging and stumbling followed even more shortly by = engine stoppage. It takes my system approx 3 - 5 seconds from the time = the pump shuts off until the engine has stopped producing power.=20 My personal preference is all critical subsystems require an overt = action by me to either turn them on or turn them off. I do not = personally like machines/software that want to do important things for = me as I have found they and I don't always agree on the needed action in = all circumstances. My suggestion is think hard about it before you = hardwire yourself into modes that may preclude you having full control = over a situation. But, then that is just my personal preference. Ed Anderson ------=_NextPart_000_0014_01C40C2D.B39A9310 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Message

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From:=20 Russell=20 Duffy
To: Rotary motors in = aircraft

Sent: Wednesday, March 17, 2004 = 1:03=20 PM

Subject: [FlyRotary] Re: = mainfold=20 hose

I was=20 trying to think of a situation where I would want the master switch = on, but=20 not want the fuel pump on. = Maybe=20 for an engine problem/shutdown, but still want to keep the radio and = navs on=20 ? =20

Steve

&nbs= p;

That's = exactly what=20 I was thinking. I prefer to have both my pumps on separate = switches, but=20 I don't see any fire hazard in regards to leaving your pump = on the=20 master. Like you said, if there's one switch you'll hit, = it's the=20 master.

&nbs= p;

Cheers,

Rusty = (hope I don't=20 get flamed=20 = <g>)
=

No=20 flames Rusty - just fire {:>).

If I=20 understand this discussion correctly, I can think of a number of = reasons I=20 might want my master switch on (on the ground) and would not want the = fuel=20 pump running. But, I would presume in that case one could pull a = circuit=20 breaker to disable the fuel pump. I would think you would hear = the pump=20 running - if not (and you canard guys might not) you might quickly run = your=20 battery down with that pump drawing its 5 - 9 amps with the Master on = because=20 you wanted to work on your intercom = wiring,etc.

Here's=20 a possible safety issue (may be far feched, but then that's the ones = that get=20 you). You have your pump wired through your master power = switch. =20 You fuel pump malfunctions - say it shorts out and starts to = draw a=20 bunch of amps in that case, unless you have the pump on a circuit = breaker (you=20 do don't you?) , you would be forced to turn off the master switch - = but wait=20 that turns off your engine!

Your=20 fuel pressure guage/alarm will give you the first indication of pump=20 failure. Then as it fall (rather quickly) below a certain level, = the=20 leaning of the mixture will cause the tone of the engine to change = follow=20 shortly by surging and stumbling followed even more shortly by engine=20 stoppage. It takes my system approx 3 - 5 seconds from the time = the pump=20 shuts off until the engine has stopped producing=20 power.

My=20 personal preference is all critical subsystems require an overt action = by me=20 to either turn them on or turn them off. I do not personally = like=20 machines/software that want to do important things for me as I have = found they=20 and I don't always agree on the needed action in all = circumstances. My=20 suggestion is think hard about it before you hardwire yourself = into=20 modes that may preclude you having full control over a=20 situation.

But,=20 then that is just my personal preference.

Ed=20 Anderson

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