Return-Path: Received: from fed1rmmtao04.cox.net ([68.230.241.35] verified) by logan.com (CommuniGate Pro SMTP 4.3c3) with ESMTP id 815109 for flyrotary@lancaironline.net; Tue, 22 Mar 2005 00:48:12 -0500 Received-SPF: none receiver=logan.com; client-ip=68.230.241.35; envelope-from=ALVentures@cox.net Received: from BigAl ([68.7.14.39]) by fed1rmmtao04.cox.net (InterMail vM.6.01.04.00 201-2131-118-20041027) with ESMTP id <20050322054720.YRSY15592.fed1rmmtao04.cox.net@BigAl> for ; Tue, 22 Mar 2005 00:47:20 -0500 From: "Al Gietzen" To: "'Rotary motors in aircraft'" Subject: Cooling delta T Date: Mon, 21 Mar 2005 21:47:33 -0800 Message-ID: <000001c52ea2$a52e45e0$6400a8c0@BigAl> MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_0001_01C52E5F.970B05E0" X-Priority: 3 (Normal) X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook, Build 10.0.6626 Importance: Normal In-Reply-To: X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2900.2180 This is a multi-part message in MIME format. ------=_NextPart_000_0001_01C52E5F.970B05E0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: quoted-printable >All we know is we don't want > the coolant to boil in there, and we know that there are potential hot > spots, particularly around the plugs that can be the limiting factor. = We > also know that heat load is much higher on the plug side of the engine than > on the other, which can lead to some thermal expansion issues if the > temperature drop across the engine gets too high; how high is to high, = I > don't know. >=20 =20 The point that concerns me the most and the question that will only be answered with experience is how much will the higher delta T effect the long term reliability. =20 Yes; we don't know the implications of higher delta T on the engine, but = we can say with confidence that more flow is better (safer) from the = standpoint of delta T and temperature distribution. For continuous high power = levels this is a consideration. =20 The other point is the since the rad inlet is limited to ~210F, we know = that the larger the temperature drop, the lower the average radiator temp = (goes down by half the increase in the delta T), and the larger the radiator = core needed to dissipate the heat; a weight and space factor. For an inlet = air temp of 80F, a coolant temp drop of 50 degrees needs about 15% more core than a 20 degree drop. Not a big deal; but something to consider. =20 I'm afraid I'm doing more trial and error although I'm trying to copycat successful systems as much as possible. =20 That's called "research". =20 Best of luck with your system. =20 Al ------=_NextPart_000_0001_01C52E5F.970B05E0 Content-Type: text/html; charset="us-ascii" Content-Transfer-Encoding: quoted-printable

>All we know is we don’t want

> the coolant to boil in there, and we know that there are potential = hot

> spots, particularly around the plugs that can be the limiting = factor. We

> also know that heat load is much higher on the plug side of the engine = than

> on the other, which can lead to some thermal expansion issues if = the

> temperature drop across the engine gets too high; how high is to high, = I

> don’t know.

>

The point that concerns me the most and the question that will only = be

answered with experience is how much will the higher delta T effect = the

long term reliability.

<= /font>

Yes; we = don’t know the implications of higher delta T on the engine, but we can say with confidence that more flow is better (safer) from the standpoint of delta = T and temperature distribution. For continuous high power levels this is a = consideration.

The other = point is the since the rad inlet is limited to ~210F, we know that the larger the = temperature drop, the lower the average radiator temp (goes down by half the = increase in the delta T), and the larger the radiator core needed to dissipate the = heat; a weight and space factor. For an inlet air temp of 80F, a coolant temp = drop of 50 degrees needs about 15% more core than a 20 degree drop. Not a big = deal; but something to consider.

I'm afraid I'm doing more trial and error although I'm trying = to

copycat successful systems as much as possible.

That’s = called “research”.

Best of luck = with your system.

Al

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