X-Virus-Scanned: clean according to Sophos on Logan.com X-SpamCatcher-Score: 2 [X] Return-Path: Received: from ms-smtp-03.southeast.rr.com ([24.25.9.102] verified) by logan.com (CommuniGate Pro SMTP 5.1.4) with ESMTP id 1737842 for flyrotary@lancaironline.net; Fri, 05 Jan 2007 08:32:16 -0500 Received-SPF: pass receiver=logan.com; client-ip=24.25.9.102; envelope-from=eanderson@carolina.rr.com Received: from edward2 (cpe-024-074-100-190.carolina.res.rr.com [24.74.100.190]) by ms-smtp-03.southeast.rr.com (8.13.6/8.13.6) with SMTP id l05CkYGu012233 for ; Fri, 5 Jan 2007 07:46:35 -0500 (EST) Message-ID: <001001c730c7$8a7f9270$2402a8c0@edward2> From: "Ed Anderson" To: "Rotary motors in aircraft" References: Subject: Re: [FlyRotary] Re: Ideal cooling Date: Fri, 5 Jan 2007 07:46:37 -0500 MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_000D_01C7309D.A15ACE30" X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook Express 6.00.2900.3028 X-MIMEOLE: Produced By Microsoft MimeOLE V6.00.2900.3028 X-Virus-Scanned: Symantec AntiVirus Scan Engine This is a multi-part message in MIME format. ------=_NextPart_000_000D_01C7309D.A15ACE30 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Like most things regarding our hobby - it all depends on objectives and = compromises. Efficiency at the component level does not necessarily = equate to system effectiveness. As an example, You could have a 100% = efficient (ok 99% - since nothings perfect) radiator but if it is too = small for the heat load its required to dissipate, then the system will = not be effective. On the other hand you can have a radiator that is = only 40% efficient but if its large enough it will still dissipate the = heat load - enabling flight.=20 I think its clear that the cooling system needs to be designed for its = intended operating environment as well as the engine installation. If I = were hauling heavy loads out of mountain valleys at high density = altitudes I would certainly design a system to deal with high power, = high heat dissipation with low airflow and air density conditions. If I = were designing a system for a 250+ MPH cruise aircraft I would not use = the same design as for the "bush" plane. For the first, I would want = the utmost heat dissipation - screw the drag (I'm not going fast = anyhow). In the second, drag would be of much higher concern in my = opinion. =20 Trying to make an inadequate cooling system functional by using a = different coolant is simply not going to work, but people keep trying. = If pure water is not doing the job, then using liquids with a lower heat = specific is only going to make it worst. Just my opinion. Ed ------=_NextPart_000_000D_01C7309D.A15ACE30 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable

Like most things regarding our hobby - it all = depends on=20 objectives and compromises. Efficiency at the component = level does=20 not necessarily equate to system effectiveness. As an example, = You=20 could have a 100% efficient (ok 99% - since nothings perfect) radiator = but if it=20 is too small for the heat load its required to dissipate, then the = system=20 will not be effective. On the other hand you can have a = radiator that=20 is only 40% efficient but if its large enough it will still = dissipate the=20 heat load - enabling flight.

I think its clear that the cooling system needs = to be=20 designed for its intended operating environment as well as the engine=20 installation. If I were hauling heavy loads out of mountain = valleys at=20 high density altitudes I would certainly design a system to deal with = high=20 power, high heat dissipation with low airflow and air density = conditions. =20 If I were designing a system for a 250+ MPH cruise aircraft I would not = use the=20 same design as for the "bush" plane. For the first, I would want = the=20 utmost heat dissipation - screw the drag (I'm not going fast = anyhow). In=20 the second, drag would be of much higher concern in my opinion. =20

Trying to make an inadequate cooling system = functional by=20 using a different coolant is simply not going to work, but people keep=20 trying. If pure water is not doing the job, then using liquids = with a=20 lower heat specific is only going to make it worst. Just my=20 opinion.

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