Return-Path: Received: from a34-mta02.direcway.com ([66.82.4.91] verified) by logan.com (CommuniGate Pro SMTP 4.2.5) with ESMTP id 523366 for flyrotary@lancaironline.net; Mon, 08 Nov 2004 16:54:47 -0500 Received-SPF: none receiver=logan.com; client-ip=66.82.4.91; envelope-from=jackbeale@direcpc.com Received: from jack (dpc691916001.direcpc.com [69.19.16.1]) by a34-mta02.direcway.com (iPlanet Messaging Server 5.2 HotFix 1.25 (built Mar 3 2004)) with SMTP id <0I6V004YFRI8SU@a34-mta02.direcway.com> for flyrotary@lancaironline.net; Mon, 08 Nov 2004 16:54:17 -0500 (EST) Date: Mon, 08 Nov 2004 16:55:16 -0500 From: Jack Beale Subject: Re: [FlyRotary] Re: EWP Info- Lynn? To: Rotary motors in aircraft Message-id: <013701c4c5dd$c7cc5d40$2619050a@jack> MIME-version: 1.0 X-MIMEOLE: Produced By Microsoft MimeOLE V6.00.2600.0000 X-Mailer: Microsoft Outlook Express 6.00.2600.0000 Content-type: multipart/alternative; boundary="Boundary_(ID_WTOuT69XXKhNyHReFcqneQ)" X-Priority: 3 X-MSMail-priority: Normal References: This is a multi-part message in MIME format. --Boundary_(ID_WTOuT69XXKhNyHReFcqneQ) Content-type: text/plain; charset=iso-8859-1 Content-transfer-encoding: 7BIT B, Yep, I agree. It would be much better to actually know the hp generated at every RPM. Seems to me, some of the guys have a motor mount setup and can swing a prop. How about combining resources...? Then again, it would give an indication of requirements even if there were no load. Jack Beale -------------------------------------------------------------------------------- ----- Original Message ----- From: Barry Gardner To: Rotary motors in aircraft Sent: Monday, November 08, 2004 4:32 PM Subject: [FlyRotary] Re: EWP Info- Lynn? Jack, your experiment below would be interesting but there is one caveat you must remember: The engine has to be under load for that to be a good test. The engine can produce next to no horsepower and be revving 2000 rpm in neutral. It won't be producing rated horsepower. On a piston engine, the way to measure the load is the BMEP (brake mean effective pressure). See http://www.tsrsoftware.com/bmep.htm for an explanation. I don't know exactly what the equivalent formula for a rotary. Think of it this way: Without a load, all that the engine needs to put out to hit 2000 (or 3000) RPM is enough HP to revolve that rotating mass of the rotors a little faster. That will be really nominal HP and a nominal cooling load. That's why engine dynos have to be harnessed to water brakes to get valid data. Barry Gardner Wheaton, IL --Boundary_(ID_WTOuT69XXKhNyHReFcqneQ) Content-type: text/html; charset=iso-8859-1 Content-transfer-encoding: 7BIT
B,
 
    Yep, I agree.  It would be much better to actually know the hp generated at every RPM.  Seems to me, some of the guys have a motor mount setup and can swing a prop.  How about combining resources...?
 
    Then again, it would give an indication of requirements even if there were no load.

Jack Beale
 
 
 
----- Original Message -----
Sent: Monday, November 08, 2004 4:32 PM
Subject: [FlyRotary] Re: EWP Info- Lynn?

Jack, your experiment below would be interesting but there is one caveat you must remember: The engine has to be under load for that to be a good test. The engine can produce next to no horsepower and be revving 2000 rpm in neutral. It won't be producing rated horsepower. On a piston engine, the way to measure the load is the BMEP (brake mean effective pressure). See http://www.tsrsoftware.com/bmep.htm for an explanation. I don't know exactly what the equivalent formula for a rotary.

Think of it this way: Without a load, all that the engine needs to put out to hit 2000 (or 3000) RPM is enough HP to revolve that rotating mass of the rotors a little faster. That will be really nominal HP and a nominal cooling load.

That's why engine dynos have to be harnessed to water brakes to get valid data.

Barry Gardner
Wheaton, IL

 
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