X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Received: from lrcmmta09-srv.windstream.net ([166.102.165.81] verified) by logan.com (CommuniGate Pro SMTP 5.3c4) with ESMTP id 4040401 for flyrotary@lancaironline.net; Thu, 24 Dec 2009 17:05:53 -0500 Received-SPF: pass receiver=logan.com; client-ip=166.102.165.81; envelope-from=montyr2157@windstream.net Return-Path: X-WS-COS: WSOB804 X-Cloudmark-Category: Undefined:Undefined X-Cloudmark-Analysis: v=1.1 cv=+7nItDkBntb9cDWargEyE9H2a6yQdV9qlRFpomtstMg= c=1 sm=0 a=ZAzGCVsrNCbRNweu8bYA:9 a=jly04x3wDz44kqipvS0A:7 a=jZjKFnXXPzlFoRkVsSunvFhg85kA:4 a=VCzWqy9gHUiZDrWy:21 a=2mxRzSsMiLbL5A6u:21 a=UretUmmEAAAA:8 a=Ia-xEzejAAAA:8 a=UeJ1hOBePTx-YANpJo0A:9 a=X_wJ0XfJILm7rxrb08QA:7 a=tfF702yzTTnNrt0zXJ8Ncir_hrQA:4 a=iVkDmfvjeKcA:10 a=EzXvWhQp4_cA:10 a=SPQdiUhDLCbww1sYP4FffA==:117 X-Cloudmark-Score: 0 Authentication-Results: lrcmmta09 smtp.user=montyr2157; auth=pass (LOGIN) Received: from [98.20.255.193] ([98.20.255.193:60136] helo=newbox) by lrcmmta09 (envelope-from ) (ecelerity 2.2.2.43 r()) with ESMTPA id 35/1C-24091-E95E33B4; Thu, 24 Dec 2009 16:05:18 -0600 Message-ID: <1960461EF9E5497A940BA6A647B21FBB@newbox> From: "MONTY ROBERTS" To: "Rotary motors in aircraft" References: Subject: Meredith Effect - Spitfire Date: Thu, 24 Dec 2009 16:05:18 -0600 MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_014E_01CA84B2.E2F877E0" X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook Express 6.00.2900.5843 X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2900.5579 This is a multi-part message in MIME format. ------=_NextPart_000_014E_01CA84B2.E2F877E0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Tracy, Oh yeah and I forgot to convert to Absolute Temp....so its only about = 30% more not 100%. Still more than the Meredith Effect. =20 Monty ----- Original Message -----=20 From: Tracy Crook=20 To: Rotary motors in aircraft=20 Sent: Thursday, December 24, 2009 3:23 PM Subject: [FlyRotary] Re: Meredith Effect - Spitfire I'm wondering if that figure for airflow is true (2x airflow for water = cooled vs air cooled). All the measurements I have seen (not many) = indicate that the exit air temperature on a Lyc installation is not = significantly different than on our water cooled engines. The total = heat per HP is not that different so my assumption is that the CFM = requirement is not much different. =20 The only advantage the air cooled engine's higher Dt gives you is that = it requires far fewer square inches of surface area to transfer a given = number of BTU with a given number of CFM. Our advantage is that we = can add surface area a LOT more easily than an air cooled can. You can = only put so many fins on a cylinder head. But I may be missing something. Other thoughts? Tracy=20 ------=_NextPart_000_014E_01CA84B2.E2F877E0 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable
Tracy,
 
Oh yeah and I forgot to convert to = Absolute=20 Temp....so its only about 30% more not 100%. Still more than the = Meredith=20 Effect.
 
Monty
----- Original Message -----
From:=20 Tracy=20 Crook
Sent: Thursday, December 24, = 2009 3:23=20 PM
Subject: [FlyRotary] Re: = Meredith Effect=20 - Spitfire

I'm wondering if that figure for airflow is true (2x = airflow=20 for water cooled vs air cooled).   All the measurements I = have seen=20 (not many) indicate that the exit air temperature on a Lyc = installation is not=20 significantly different than on our water cooled engines.   The = total=20 heat per HP is not that different so my assumption is that the CFM = requirement=20 is not much different. 

The only advantage the air cooled = engine's higher Dt gives you is that it requires far fewer square = inches of=20 surface area to transfer a given number of BTU with a given number of=20 CFM.    Our advantage is that we can add surface area a LOT = more=20 easily than an air cooled can.  You can only put so many fins on = a=20 cylinder head.

But I may be missing something.  Other=20 thoughts?

Tracy

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