Return-Path: Received: from [24.25.9.101] (HELO ms-smtp-02-eri0.southeast.rr.com) by logan.com (CommuniGate Pro SMTP 4.1.8) with ESMTP id 2783899 for flyrotary@lancaironline.net; Thu, 04 Dec 2003 17:54:51 -0500 Received: from o7y6b5 (clt78-020.carolina.rr.com [24.93.78.20]) by ms-smtp-02-eri0.southeast.rr.com (8.12.10/8.12.7) with SMTP id hB4Mslaw002423 for ; Thu, 4 Dec 2003 17:54:49 -0500 (EST) Message-ID: <002501c3bab9$2c783f60$1702a8c0@WorkGroup> From: "Ed Anderson" To: "Rotary motors in aircraft" References: Subject: Re: [FlyRotary] Re: K&M and Thick Radiators Date: Thu, 4 Dec 2003 17:51:36 -0500 MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_0022_01C3BA8F.435F13E0" X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook Express 6.00.2800.1106 X-MIMEOLE: Produced By Microsoft MimeOLE V6.00.2800.1106 X-Virus-Scanned: Symantec AntiVirus Scan Engine This is a multi-part message in MIME format. ------=_NextPart_000_0022_01C3BA8F.435F13E0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable =20 If removing the highest amount heat per unit of air flow is the = criteria; then thick radiators with close fin spacing and slow air flow = is the way to go. When you add the other criteria of fixed dynamic head = (pressure), area constraints, drag, and weight; and maybe a few others; = that is no longer the case. Parametric studies using fairly sophisticated analytical models that I = have seen suggests that for our aircraft applications the optimum lies = somewhere in the 2-3" thickness range. And this of course will depend = on some configuration variables. This is also for an optimally designed = radiator. A optimally designed AC evaporator may be a bit different = because it is designed for a different fluid. =20 Al Couldn't agree more, Al. Since the NASCAR radiators average 3" thick = and they operate in the general speed range we do, 2-3" sounds good to = me. 3.6" thick work for the evaporator cores, but I would say that = dynamic pressure is a bit lacking for that thickness on climbout at = slower airspeeds. =20 As I mentioned, dynamic pressure (or lack thereof) would certainly be = a major factor in determining optimum thickness for a particualr regime = of flight as would pressure recovery in the duct, heat exchanger = parameters such as fin spacing, fin configuration, etc, etc. So like most other decisions, cooling decisions force a series of = compromises. Ed ------=_NextPart_000_0022_01C3BA8F.435F13E0 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable

If = removing the=20 highest amount heat per unit of air flow is the criteria; then thick = radiators=20 with close fin spacing and slow air flow is the way to go. When = you add=20 the other criteria of fixed dynamic head (pressure), area constraints, = drag,=20 and weight; and maybe a few others; that is no longer the=20 case.

Parametric studies=20 using fairly sophisticated analytical models that I have seen suggests = that=20 for our aircraft applications the optimum lies somewhere in the 2-3=94 = thickness=20 range. And this of course will depend on some configuration=20 variables. This is also for an optimally designed radiator. = A=20 optimally designed AC evaporator may be a bit different because it is = designed=20 for a different fluid.

Al

Couldn't = agree=20 more, Al. Since the NASCAR radiators average 3" thick and they = operate=20 in the general speed range we do, 2-3" sounds good to me. 3.6" thick = work for=20 the evaporator cores, but I would say that dynamic pressure is a bit = lacking=20 for that thickness on climbout at slower airspeeds. =

As I=20 mentioned, dynamic pressure (or lack thereof) would certainly be a = major=20 factor in determining optimum thickness for a particualr regime of = flight as=20 would pressure recovery in the duct, heat exchanger parameters such as = fin=20 spacing, fin configuration, etc, etc.

So like = most other=20 decisions, cooling decisions force a series of = compromises.

Ed

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