Return-Path: Received: from fed1rmmtao01.cox.net ([68.230.241.38] verified) by logan.com (CommuniGate Pro SMTP 4.2) with ESMTP id 360929 for flyrotary@lancaironline.net; Wed, 11 Aug 2004 09:44:59 -0400 Received-SPF: none receiver=logan.com; client-ip=68.230.241.38; envelope-from=ALVentures@cox.net Received: from BigAl ([68.107.116.221]) by fed1rmmtao01.cox.net (InterMail vM.6.01.03.02.01 201-2131-111-104-103-20040709) with ESMTP id <20040811134426.DTYP6617.fed1rmmtao01.cox.net@BigAl> for ; Wed, 11 Aug 2004 09:44:26 -0400 From: "Al Gietzen" To: "'Rotary motors in aircraft'" Subject: RE: [FlyRotary] Re: Pressure switch Date: Wed, 11 Aug 2004 06:44:31 -0700 Message-ID: <000001c47fa9$5496dc30$6400a8c0@BigAl> MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_0001_01C47F6E.A8380430" X-Priority: 3 (Normal) X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook, Build 10.0.6626 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_01C47F6E.A8380430 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: quoted-printable Subject: [FlyRotary] Re: Pressure switch =20 Al, that switch will work either way. I have one and am using it so = that is N.C . It closes when my coolant pressure drops and lights the indicator = on engine monitor. That occurs at about 5 psi. The only thing I am = unsure about in your application is the rated amperage since you want to use it = to power a fuel pump. I can't remember if it was 3 amps or 10 amps. =20 Dave Leonard =20 Oops. I didn't look at the diagram carefully enough to note that it = could be wired either way. I'm thinking that a higher pressure switching = point is needed, like at least 20-25 psi. The idea is to catch it before the = engine stops, and it's likely that would happen before the backup would get it = up to pressure. It may be best to simply run both during critical flight phases, which I probably would anyway. Just seems like it would be good = to have the backup come on automatically and keep the engine running so = when your droning along at cruise you don't have a huge pucker factor (and = cause cardiac arrest with your passengers) if the engine suddenly quits. =20 I doubt that the pressure switch would handle switching pump amps = directly for very long. A relay is required. =20 Two questions: Does the engine 'windmill' if turned off during cruise? How much does your pressure regulator drop the pressure at low MAP? =20 Al http://www.bandc.biz/S8012.html =20 ------=_NextPart_000_0001_01C47F6E.A8380430 Content-Type: text/html; charset="us-ascii" Content-Transfer-Encoding: quoted-printable Message

Subject: [FlyRotary] Re: Pressure switch

 

Al, that switch will work either way.  I have one and am using it so = that is N.C .  It closes when my = coolant pressure drops and lights the indicator on engine = monitor.   That occurs at about 5 psi.  The only thing I am unsure about in = your application is the rated amperage since you want to use it to power a fuel = pump.  I can't remember if it was 3 amps or 10 amps.

 

Dave = Leonard

 

Oops.  I didn’t look = at the diagram carefully enough to note that it could be wired either way. =  I’m thinking that a higher pressure switching point is needed, like at least = 20-25 psi.  The idea is to catch it before the engine stops, and it’s = likely that would happen before the backup would get it up to pressure. =  It may be best to simply run both during critical flight phases, which I = probably would anyway.  Just seems like it would be good to have the backup = come on automatically and keep the engine running so when your droning along at = cruise you don’t have a huge pucker factor (and cause cardiac arrest with = your passengers) if the engine suddenly quits.

 

I doubt that the pressure switch = would handle switching pump amps directly for very long.  A relay is = required.

 

Two questions: Does the engine = ‘windmill’ if turned off during cruise?

     &nbs= p;            = ;      How much does your pressure regulator drop the pressure at low = MAP?

 

Al

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