Return-Path: Received: from fed1mtao05.cox.net ([68.6.19.126] verified) by logan.com (CommuniGate Pro SMTP 4.1.8) with ESMTP id 2760655 for flyrotary@lancaironline.net; Fri, 21 Nov 2003 14:34:36 -0500 Received: from BigAl ([68.107.116.221]) by fed1mtao05.cox.net (InterMail vM.5.01.06.05 201-253-122-130-105-20030824) with ESMTP id <20031121193432.EWVY9968.fed1mtao05.cox.net@BigAl> for ; Fri, 21 Nov 2003 14:34:32 -0500 From: "Al Gietzen" To: "'Rotary motors in aircraft'" Subject: RE: [FlyRotary] Re: radiator Date: Fri, 21 Nov 2003 11:34:37 -0800 Message-ID: <000801c3b066$80329fe0$6400a8c0@BigAl> MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_0009_01C3B023.720F5FE0" X-Priority: 3 (Normal) X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook, Build 10.0.4024 In-Reply-To: Importance: Normal X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2800.1165 This is a multi-part message in MIME format. ------=_NextPart_000_0009_01C3B023.720F5FE0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Just a comment on one of the "assumptions" we all start with when discussing estimation of cooling system sizes for hot weather: How much hp is being developed, i.e., how much heat is to be rejected? - I wonder if everyone is "assuming" that they must calculate radiator areas based on heat being generated/to be rejected while generating 100% power, i.e., 160 or up to 180-205 for a n/a rotary, depending on what you think you will be getting? -- My point is this: At a 90 or 100 degree F day, at full throttle, sea level, std day pressure (29.92), you won't be generating 100% power - because, you are sucking in hot ambient air through the induction system (lower density than standard) and, without looking up the equations for normalizing measured performance to "std day", I guess we'll be generating only 90% of the 160 or so hp. That's true. That is one of the considerations built into my assumption of designing to 80% of full power on a hot day. The other thing is, it would probably very fortuitous if your actual performance fell within +-10%, or even +-20% of your design point anyway. Al ------=_NextPart_000_0009_01C3B023.720F5FE0 Content-Type: text/html; charset="us-ascii" Content-Transfer-Encoding: quoted-printable

 

 Just a comment on one of the "assumptions" we all start with = when

discussing estimation of cooling system sizes for hot weather:  How much = hp

is being developed, i.e., how much heat is to be = rejected?

   - I wonder if everyone is "assuming" that they must calculate radiator

areas based on heat being generated/to be rejected while generating = 100%

power, i.e., 160 or up to 180-205 for a n/a rotary, depending on what = you

think you will be getting?

        --  My point is this:  At a 90 or 100 degree F day, at = full

throttle, sea level, std day pressure (29.92), you won't be generating = 100%

power - because, you are sucking in hot ambient air through the = induction

system (lower density than standard) and, without looking up the = equations

for normalizing measured performance to "std day", I guess we'll = be

generating only 90% of the 160 or so hp.

 

That’s true.  That is one of the considerations built into my assumption = of designing to 80% of full power on a hot day.  The other thing is, = it would probably very fortuitous if your actual performance fell within +-10%, = or even +-20% of your design point anyway.

 <= /font>

Al

------=_NextPart_000_0009_01C3B023.720F5FE0--