X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Received: from fed1rmmtao106.cox.net ([68.230.241.40] verified) by logan.com (CommuniGate Pro SMTP 5.2.16) with ESMTP id 3816540 for flyrotary@lancaironline.net; Tue, 18 Aug 2009 01:00:33 -0400 Received-SPF: none receiver=logan.com; client-ip=68.230.241.40; envelope-from=alventures@cox.net Received: from fed1rmimpo01.cox.net ([70.169.32.71]) by fed1rmmtao106.cox.net (InterMail vM.8.00.01.00 201-2244-105-20090324) with ESMTP id <20090818045954.DFQZ21192.fed1rmmtao106.cox.net@fed1rmimpo01.cox.net> for ; Tue, 18 Aug 2009 00:59:54 -0400 Received: from BigAl ([72.192.133.78]) by fed1rmimpo01.cox.net with bizsmtp id Vgzv1c00B1hf1Cg03gzvF8; Tue, 18 Aug 2009 00:59:55 -0400 X-VR-Score: 0.00 X-Authority-Analysis: v=1.0 c=1 a=ybW0dUwbh0Gm98MYmWUA:9 a=NajYCvkcr6KAJQvu_ugPMN6Vt0UA:4 a=CEFvqdEhXOjMWduggIUA:9 a=3_QT42Zmfq9CdCe5qUkA:7 a=MKuD_gobxnTPlhXPCjZ531KxWy4A:4 X-CM-Score: 0.00 From: "Al Gietzen" To: "'Rotary motors in aircraft'" Subject: RE: [FlyRotary] Swirl pots Date: Mon, 17 Aug 2009 22:00:31 -0800 Message-ID: MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_0000_01CA1F86.23CC49F0" X-Priority: 3 (Normal) X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook, Build 10.0.6838 Importance: Normal Thread-Index: AcofrqEJxlW+UTvTQH6nSaOqXenxkwAFeOAg In-Reply-To: X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2900.5579 This is a multi-part message in MIME format. ------=_NextPart_000_0000_01CA1F86.23CC49F0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: quoted-printable I respectfully disagree with the idea of the putting a flow restriction = at the exit of the engine. True, it does increase the coolant pressure in = the block, and that's good. But it reduces flow, and that's bad. Reduced = flow increases the delta T around the loop and reduces the cooling capacity = of the radiator, and in an aircraft application we don't like to add = additional radiator size. As far as increasing the pressure in the block, you can = get about the same affect by plumbing the filler/pressure cap to the inlet = side of the pump rather than the outlet, so the pressure drop around the loop = is not seen by the cap. A swirl pot works, but is not necessary. You need an air bleed from the high point of the engine (usually the outlet of the pump, and from other places that the air may get trapped, like the rad tank. A small bleed = line (3/16" o.d. aluminum is good) from the point the air gets trapped back = to the filler neck/bottle. Since the filler neck is plumbed to the low pressure side of the loop, any air gets drawn back there. I connected the turbo coolant port on the rear iron of my 20B back to = the port on the pump outlet to bleed air from the rear iron, and a manual = bleed plug at the pump outlet to vent air during fillup. I have small bleed = lines from each of two custom radiator tanks back to the filler neck (which is connected to the line just before the pump inlet). After fillup, one = run cycle purges all the air back to the filler neck. BTW; the cold to hot expansion for my 20B system is about 2/3 of a = quart. Works for me, but of course each installation is different; but the = concept is the same. Al G =20 ------=_NextPart_000_0000_01CA1F86.23CC49F0 Content-Type: text/html; charset="us-ascii" Content-Transfer-Encoding: quoted-printable

I respectfully disagree with the = idea of the putting a flow restriction at the exit of the engine.  True, it = does increase the coolant pressure in the block, and that’s good. But = it reduces flow, and that’s bad.  Reduced flow increases the = delta T around the loop and reduces the cooling capacity of the radiator, and in = an aircraft application we don’t like to add additional radiator = size.  As far as increasing the pressure in the block, you can get about the = same affect by = plumbing the filler/pressure cap to the inlet side of the pump rather than the = outlet, so the pressure drop around the loop is not seen by the = cap.

A swirl pot works, but is not necessary.  You need an air bleed from the high point of the engine (usually the outlet of the pump, and from other places that the air may = get trapped, like the rad tank.  A small bleed line (3/16” o.d. = aluminum is good) from the point the air gets trapped back to the filler = neck/bottle.  Since the filler neck is plumbed to the low pressure side of the loop, any air = gets drawn back there.

I connected the turbo coolant = port on the rear iron of my 20B back to the port on the pump outlet to bleed air = from the rear iron, and a manual bleed plug at the pump outlet to vent air = during fillup.  I have small bleed lines from each of two custom radiator = tanks back to the filler neck (which is connected to the line just before the = pump inlet).  After fillup, one run cycle purges all the air back to the = filler neck.

BTW; the cold to hot expansion = for my 20B system is about 2/3 of a quart.

Works for me, but of course each = installation is different; but the concept is the same.

Al G

 

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