Return-Path: Received: from [65.54.169.188] (HELO hotmail.com) by logan.com (CommuniGate Pro SMTP 4.1.5) with ESMTP id 2643854 for flyrotary@lancaironline.net; Mon, 20 Oct 2003 14:17:51 -0400 Received: from mail pickup service by hotmail.com with Microsoft SMTPSVC; Mon, 20 Oct 2003 11:17:46 -0700 Received: from 65.137.50.81 by bay3-dav158.bay3.hotmail.com with DAV; Mon, 20 Oct 2003 18:17:46 +0000 X-Originating-IP: [65.137.50.81] X-Originating-Email: [lors01@msn.com] Reply-To: "Tracy Crook" From: "Tracy Crook" To: "Rotary motors in aircraft" References: Subject: Re: [FlyRotary] Re: Water pumps Somebody STOP me! Date: Mon, 20 Oct 2003 14:20:24 -0400 Organization: Real World Solutions Inc. MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_007A_01C39715.4D454AC0" 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 Message-ID: X-OriginalArrivalTime: 20 Oct 2003 18:17:46.0631 (UTC) FILETIME=[765C8970:01C39736] This is a multi-part message in MIME format. ------=_NextPart_000_007A_01C39715.4D454AC0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Excellent chart Bill, it shows it all. I'm sure you are right about the = EWP HP saved claim although I think the success of the EWP is due to = several factors. Just a SWAG but I think they are: 1. As you said, The EWP never runs at the high end of the rpm spectrum = where the stock pump is absorbing excessive HP (and perhaps a *little* = more flow). 2. The cooling requirements of the engine do not need the upper limit = of flow that a mechanical WP could provide. 3. The efficiency of the EWP is probably much better than the engine = driven pump so it doesn't need as much power for a give flow rate & = head. Haven't seen the DC pump innards but the Mezzier EWP is a = surgeon's tool if the stock WP is an axe. The EWP pessimists always point to "More flow is better" which is = correct to a point, but ignores the real world requirements of what it = takes to do the job. Another case of perfect being the enemy of good = maybe. Tracy Crook Here is a .GIF that illustrates both our points. At zero flow, the = pump shaft horsepower is less than at rated flow, but all the energy is = going into heating the water. I believe that the reason Davies Craig claims that they save a lot of = horsepower, is because at high rpm, the pump is not running at its high = efficiency point. It is clear from the successful EWP tests of Todd, = that the actual energy required to pump the water is small. So if DC is = correct, then they are using the high rpm point for the "horsepower = saved". Bill Schertz ------=_NextPart_000_007A_01C39715.4D454AC0 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable

Excellent chart Bill, it shows it = all. I'm=20 sure you are right about the EWP HP saved claim although I think the = success of=20 the EWP is due to several factors. Just a SWAG but I think they=20 are:

1. As you said, The EWP never = runs at the=20 high end of the rpm spectrum where the stock pump is = absorbing excessive HP=20 (and perhaps a *little* more flow).

2. The cooling requirements of = the engine do=20 not need the upper limit of flow that a mechanical WP could=20 provide.

3. The efficiency of the EWP is = probably much=20 better than the engine driven pump so it doesn't need as much power for = a give=20 flow rate & head. Haven't seen the DC pump innards but the=20 Mezzier EWP is a surgeon's tool if the stock WP is an = axe.

The EWP pessimists always point to = "More flow is=20 better" which is correct to a point, but ignores the real world = requirements of=20 what it takes to do the job. Another case of perfect being the = enemy of=20 good maybe.

Tracy Crook

Here is a .GIF that illustrates both = our points.=20 At zero flow, the pump shaft horsepower is less than at rated flow, = but all=20 the energy is going into heating the water.

I believe that the reason Davies = Craig claims=20 that they save a lot of horsepower, is because at high rpm, the pump = is not=20 running at its high efficiency point. It is clear from the successful = EWP=20 tests of Todd, that the actual energy required to pump the water is = small. So=20 if DC is correct, then they are using the high rpm point for the = "horsepower=20 saved".

Bill Schertz

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