X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Received: from cdptpa-omtalb.mail.rr.com ([75.180.132.122] verified) by logan.com (CommuniGate Pro SMTP 5.3.9) with ESMTP id 4464856 for flyrotary@lancaironline.net; Mon, 13 Sep 2010 08:56:10 -0400 Received-SPF: pass receiver=logan.com; client-ip=75.180.132.122; envelope-from=eanderson@carolina.rr.com Return-Path: X-Authority-Analysis: v=1.1 cv=p2+AJtORPCqgiIb1GLnEzM38JG/9906BinLiWeI6YUU= c=1 sm=0 a=Y_lblG3xEFsA:10 a=rPkcCx1H5rrOSfN0dPC7kw==:17 a=SJYIoTHGoI8QDYf6JZEA:9 a=PiqV1WfFnNyAWGRE4Rrrg8vXwq0A:4 a=wPNLvfGTeEIA:10 a=yMhMjlubAAAA:8 a=1oqGTYSLAAAA:8 a=Ia-xEzejAAAA:8 a=pflxJXtKNBqFNBxj91MA:9 a=t26PSCA-NkfiejJKCmcA:7 a=HuNuwVDYX8TqsvUjDGRoAwkaXSQA:4 a=cvn8laQl214A:10 a=EzXvWhQp4_cA:10 a=rPkcCx1H5rrOSfN0dPC7kw==:117 X-Cloudmark-Score: 0 X-Originating-IP: 174.110.167.5 Received: from [174.110.167.5] ([174.110.167.5:63274] helo=EdPC) by cdptpa-oedge02.mail.rr.com (envelope-from ) (ecelerity 2.2.2.39 r()) with ESMTP id 0C/AF-06845-64F1E8C4; Mon, 13 Sep 2010 12:55:34 +0000 Message-ID: <4E4EB84201544070BA4BBE40AE52C414@EdPC> From: "Ed Anderson" To: "Rotary motors in aircraft" References: In-Reply-To: Subject: Re: [FlyRotary] Radiator cap - system pressure Date: Mon, 13 Sep 2010 08:55:29 -0400 MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_0116_01CB5321.6A64ACC0" X-Priority: 3 X-MSMail-Priority: Normal Importance: Normal X-Mailer: Microsoft Windows Live Mail 14.0.8117.416 X-MimeOLE: Produced By Microsoft MimeOLE V14.0.8117.416 This is a multi-part message in MIME format. ------=_NextPart_000_0116_01CB5321.6A64ACC0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Chris, I have run with a 21-23 psi radiator cap for over 10 years with = no adverse affects. Most caps use atmospheric pressure in addition to = spring/gasket to hold the pressure. Therefore as you increase in = altitude the contribution of the atmosphere to holding the pressure is = reduced. I know of a couple of incidents where folks were using 14 psi = caps and found that at altitude the cap would not hold against the = cooling pressure and they had fluid in their overflow recovery can. I = personally would not use less that a 21 psi cap. Others may offer = different suggestions - but that is my experience. I probably would not = normally go above 25 psi cap - but if a 29 psi cap was all I had, I = would not hesitate to use it. Theoretically if you maintain too high a pressure in the system then you = could cause leaks around pump seals and else where - but, if the = pressure gets that high you undoubtedly have other problems {:>) Ed From: Chris and Terria=20 Sent: Monday, September 13, 2010 6:56 AM To: Rotary motors in aircraft=20 Subject: [FlyRotary] Radiator cap - system pressure Gents, =20 What pressure caps are you running with? What maximum should be used? = I currently have a 16 lb cap, but have found ones up to 29 - 31 lbs. I = know more pressure means more cooling, but is there a maximum limit = before hurting the engine? =20 Chris ------=_NextPart_000_0116_01CB5321.6A64ACC0 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable
Chris, I have run with a 21-23 psi radiator cap = for over=20 10 years with no adverse affects.  Most caps use atmospheric = pressure in=20 addition to spring/gasket to hold the pressure.  Therefore as you = increase=20 in altitude the contribution of the atmosphere to holding the pressure = is=20 reduced.  I know of a couple of incidents where folks were using 14 = psi=20 caps and found that at altitude the cap would not hold against the = cooling=20 pressure and they had fluid in their overflow recovery can.  I = personally=20 would not use less that a 21 psi cap.  Others may offer different=20 suggestions - but that is my experience.  I probably would not = normally go=20 above 25 psi cap - but if a 29 psi cap was all I had, I would not = hesitate to=20 use it.
 
Theoretically if you maintain too high a = pressure in the=20 system then you could cause leaks around pump seals and else where - = but, if the=20 pressure gets that high you undoubtedly have other problems=20 {:>)
 
Ed

Sent: Monday, September 13, 2010 6:56 AM
To: Rotary motors in = aircraft
Subject: [FlyRotary] Radiator cap - system=20 pressure

Gents,

 

What pressure caps are you running with?  What = maximum=20 should be used?  I currently have a 16 lb cap, but have found ones = up to 29=20 =96 31 lbs.  I know more pressure means more cooling, but is there = a maximum=20 limit before hurting the engine?

 

Chris

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