X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Received: from fed1rmmtao02.cox.net ([68.230.241.37] verified) by logan.com (CommuniGate Pro SMTP 4.3.5) with ESMTP id 1020829 for flyrotary@lancaironline.net; Fri, 24 Jun 2005 17:02:48 -0400 Received-SPF: none receiver=logan.com; client-ip=68.230.241.37; envelope-from=ALVentures@cox.net Received: from BigAl ([68.7.14.39]) by fed1rmmtao02.cox.net (InterMail vM.6.01.04.00 201-2131-118-20041027) with ESMTP id <20050624210203.PHNR22430.fed1rmmtao02.cox.net@BigAl> for ; Fri, 24 Jun 2005 17:02:03 -0400 From: "Al Gietzen" To: "'Rotary motors in aircraft'" Subject: Coolant Leak Date: Fri, 24 Jun 2005 14:02:06 -0700 Message-ID: <000001c578ff$fae54450$6400a8c0@BigAl> MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_0001_01C578C5.4E866C50" 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_01C578C5.4E866C50 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: quoted-printable =20 A couple of things. Tracy and I both discovered that once ALL the air = is out of the coolant system, the coolant pressure may jump to 21 psi = almost immediately upon start up - long before the heat would cause it to build = to that point. At first, I thought "coolant Leak", however, I could never = find any evidence of coolant in the chambers nor loss of coolant in the = system. Talking to Tracy Crook, he reported the same thing. We came to the conclusion that without a small cushion of air that the pressure sensor = was seeing hydraulic pressure caused by the pump. =20 =20 Maybe not. How/why would the pump pressurize the system? There will be some pressure differential across the pump, and downstream from the pump = you will see the drop around the loop; but not 21 psi.=20 =20 Maybe depends on what you mean by "almost immediately". With no air in = the system a small amount of expansion will cause a pressure increase. I = recall seeing over 20 psi when the temp was only up to 125F. =20 Al ------=_NextPart_000_0001_01C578C5.4E866C50 Content-Type: text/html; charset="us-ascii" Content-Transfer-Encoding: quoted-printable

 

=

A couple of things.  = Tracy and I both discovered that once ALL the air is out of the coolant system, the coolant pressure may jump = to 21 psi almost immediately upon start up - long before the heat would cause = it to build to that point.  At first, I thought "coolant Leak", however, I could never find any evidence of coolant in the chambers nor = loss of coolant in the system.  Talking to Tracy Crook, he reported the same thing.  We came = to the conclusion that without a small cushion of air that the pressure sensor = was seeing hydraulic pressure caused by the pump. 

 

Maybe not.  How/why would = the pump pressurize the system?  There will be some pressure differential = across the pump, and downstream from the pump you will see the drop around the = loop; but not 21 psi.

 

Maybe depends on what you mean by = “almost immediately”.  With no air in the system a small amount of = expansion will cause a pressure increase.  I recall seeing over 20 psi when = the temp was only up to 125F.

 

Al

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