Return-Path: Sender: (Marvin Kaye) To: flyrotary Date: Thu, 03 Oct 2002 19:08:09 -0400 Message-ID: X-Original-Return-Path: Received: from cpimssmtpu01.email.msn.com ([207.46.181.77] verified) by logan.com (CommuniGate Pro SMTP 4.0b8) with ESMTP id 1796942 for flyrotary@lancaironline.net; Thu, 03 Oct 2002 10:50:18 -0400 Received: from BigAl ([64.167.189.146]) by cpimssmtpu01.email.msn.com with Microsoft SMTPSVC(5.0.2195.4905); Thu, 3 Oct 2002 07:49:05 -0700 X-Original-Message-ID: <002901c26aec$309bacd0$eb01a8c0@BigAl> From: "Al Gietzen" X-Original-To: "Rotary motors in aircraft" References: Subject: Re: [FlyRotary] Re: water pumps X-Original-Date: Thu, 3 Oct 2002 07:50:15 -0700 MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_0026_01C26AB1.82BF5C90" X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook Express 6.00.2600.0000 X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2600.0000 X-Original-Return-Path: alventures@email.msn.com X-OriginalArrivalTime: 03 Oct 2002 14:49:06.0760 (UTC) FILETIME=[06235480:01C26AEC] This is a multi-part message in MIME format. ------=_NextPart_000_0026_01C26AB1.82BF5C90 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable That makes sense. But I got to wondering as to exactly what = conditions the pump _and pulley!_ were designed around. What if, at 5000 or more rpm at = cruise, we have more capacity than we need, and end up pumping a lot of back = pressure against a partially closed thermostat. A scenario like that would be = wasted power. If that were so, and we just put a larger pulley on the pump, = it would not absorb as much power, and the lower pump rpm would better match requirements. How do we tell if a water pump/pulley configuration is = wasting power trying to over achieve? Has anyone tried a larger pulley (less = pump speed, less power drain, less flow, but still plenty sufficient for the = application)?? Tracy, are you out there?? Inquiring minds need to know .... Jim S. With the Mazda thermostat setup, as the thermostat closes it = recirculates the coolant through the engine. Probably less back = pressure than going through the engine and around the cooling loop. My analysis indicates that you need all the flow you can get for = takeoff and climb out. A larger pulley could get you in trouble. Al G ------=_NextPart_000_0026_01C26AB1.82BF5C90 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable

That makes sense. But I got to wondering as to exactly what = conditions the pump
_and pulley!_ were designed around. What = if, at=20 5000 or more rpm at cruise, we
have more capacity than we need, and = end up=20 pumping a lot of back pressure
against a partially closed = thermostat. =20 A scenario like that would be wasted
power. If that were so, = and we=20 just put a larger pulley on the pump, it would
not absorb as much = power,=20 and the lower pump rpm would better match
requirements. How = do we=20 tell if a water pump/pulley configuration is wasting
power trying = to over=20 achieve? Has anyone tried a larger pulley (less pump = speed,
less=20 power drain, less flow, but still plenty sufficient for the=20 application)??
Tracy, are you out there??
Inquiring minds need = to know=20 .... Jim S.

With the Mazda thermostat setup, as the = thermostat=20 closes it recirculates the coolant through the engine. Probably = less=20 back pressure than going through the engine and around the cooling=20 loop.

My analysis indicates that you need all the = flow you=20 can get for takeoff and climb out. A larger pulley could get you = in=20 trouble.

Al G

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