X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Received: from fed1rmmtao103.cox.net ([68.230.241.43] verified) by logan.com (CommuniGate Pro SMTP 5.2.16) with ESMTP id 3845237 for flyrotary@lancaironline.net; Thu, 10 Sep 2009 20:09:02 -0400 Received-SPF: none receiver=logan.com; client-ip=68.230.241.43; envelope-from=alventures@cox.net Received: from fed1rmimpo01.cox.net ([70.169.32.71]) by fed1rmmtao103.cox.net (InterMail vM.8.00.01.00 201-2244-105-20090324) with ESMTP id <20090911000827.FICY11920.fed1rmmtao103.cox.net@fed1rmimpo01.cox.net> for ; Thu, 10 Sep 2009 20:08:27 -0400 Received: from BigAl ([72.192.133.78]) by fed1rmimpo01.cox.net with bizsmtp id fC8T1c0071hf1Cg03C8TVv; Thu, 10 Sep 2009 20:08:27 -0400 X-VR-Score: 0.00 X-Authority-Analysis: v=1.0 c=1 a=OufRhYqAkogA:10 a=f_Nqlv-nl90Pu_aOjwoA:9 a=i6qIUA3x9wBXskhH2Jix85jvH-sA:4 a=YiUFUDYeNz8ci2YfEicA:9 a=X32vlomFhB_JNCfduYsA:7 a=k3OdamfcpkkvmT4p6PEVE_5gTGIA:4 X-CM-Score: 0.00 From: "Al Gietzen" To: "'Rotary motors in aircraft'" Subject: RE: [FlyRotary] cooling plumbing design [ right?, right? :-) ] Date: Thu, 10 Sep 2009 17:09:52 -0800 Message-ID: MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_0000_01CA3239.82EC4F50" X-Priority: 3 (Normal) X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook, Build 10.0.6838 Importance: Normal Thread-Index: AcoyRpfWT7DPygJGS6uEih+OdvFMyAANRmIg 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_01CA3239.82EC4F50 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: quoted-printable =20 Guys, We have two schools of thought going in this discussion and have had = for some time..........One=20 opinion has the bottom of the expansion tank plumbed to the "Outlet" of = the pump (as Tracy does & others)..........The other has the bottom of the expansion tank plumbed = to the "Inlet" of the pump (as Al G., Mark S. & others do)..........I believe the inlet position = came from the "Stewart Racing Pump" site...........The rational being that this was the lowest = pressure site of the cooling system and would not subject the system pressure "Cap" (on the expansion tank) to = both system and pumping pressure Yes; both ways work. If the 'expansion tank' is also where the pressure = cap is; there are two advantages to connecting to the low pressure (inlet) = side of the pump - slightly greater resistance to boiling and slightly = greater resistance to pump cavitation; both due to the system pressure under = high power being higher by the amount of the pressure drop around the loop. =20 Air bleed lines can be very small; like 3/16" aluminum, or equivalent; = which will bleed air just fine, but flow a negligible amount of coolant; so = bypass flow is not an issue. =20 Al G ------=_NextPart_000_0000_01CA3239.82EC4F50 Content-Type: text/html; charset="us-ascii" Content-Transfer-Encoding: quoted-printable

 

Guys,

   We have two schools of thought = going in this discussion and have had for some time..........One =

opinion has the bottom of the expansion tank = plumbed to the "Outlet" of the pump (as Tracy does = &

others)..........The other has the bottom of = the expansion tank plumbed to the "Inlet" of the = pump

(as Al G., Mark S. & others = do)..........I believe the inlet position came from the "Stewart Racing

Pump" site...........The rational being = that this was the lowest pressure site of the cooling system = and

would not subject the system pressure "Cap"  (on the expansion tank) to both system and = pumping

pressure

Yes; both ways work.  If the = ‘expansion tank’ is also where the pressure cap is; there are two advantages = to connecting to the low pressure (inlet) side of the pump – slightly = greater resistance to boiling and slightly greater resistance to pump = cavitation; both due to the system pressure under high power being higher by the amount = of the pressure drop around the loop.

 

Air bleed lines can be very = small; like 3/16” aluminum, or equivalent; which will bleed air just fine, but = flow a negligible amount of coolant; so bypass flow is not an = issue.

 

Al G

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