X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Received: from fed1rmmtao105.cox.net ([68.230.241.41] verified) by logan.com (CommuniGate Pro SMTP 5.3c3) with ESMTP id 4022868 for flyrotary@lancaironline.net; Tue, 15 Dec 2009 20:45:25 -0500 Received-SPF: none receiver=logan.com; client-ip=68.230.241.41; envelope-from=alventures@cox.net Received: from fed1rmimpo01.cox.net ([70.169.32.71]) by fed1rmmtao105.cox.net (InterMail vM.8.00.01.00 201-2244-105-20090324) with ESMTP id <20091216014450.FFEZ12229.fed1rmmtao105.cox.net@fed1rmimpo01.cox.net> for ; Tue, 15 Dec 2009 20:44:50 -0500 Received: from BigAl ([72.192.136.150]) by fed1rmimpo01.cox.net with bizsmtp id Hdkp1d00M3EsL8g03dkpbH; Tue, 15 Dec 2009 20:44:50 -0500 X-VR-Score: 0.00 X-Authority-Analysis: v=1.1 cv=dPH3qklg8Vic3E1mcpSlAaa4ZLB04ixhaZIb8bf8Di4= c=1 sm=1 a=+xS8pRtGb5GgEi4xmYelzg==:17 a=C2_ygiGB1fULmfoTxKoA:9 a=Kt_ASGS8wjM2nT5Mhch-m0MfescA:4 a=Y2VNeNrzAAAA:8 a=yMhMjlubAAAA:8 a=TW66zc2HAAAA:8 a=SSmOFEACAAAA:8 a=HQ31llbKAAAA:8 a=qYFjTto73z-gCN_dbpgA:9 a=6xC7YtkgnT5gZvHlmicA:7 a=8KLHOHqeeQKnSAuitiJotp1TKsgA:4 a=+xS8pRtGb5GgEi4xmYelzg==:117 X-CM-Score: 0.00 From: "Al Gietzen" To: "'Rotary motors in aircraft'" Subject: RE: [FlyRotary] Re: Oil cooler Date: Tue, 15 Dec 2009 17:45:15 -0800 Message-ID: <751B3E8BADCB41BF8026C6D8D2AFCA08@BigAl> MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_000C_01CA7DAE.5BD3D030" X-Priority: 3 (Normal) X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook, Build 10.0.6856 Importance: Normal Thread-Index: Acp9w3BS3YdW0fXZQkCXY63y3+okCQAKXI+A In-Reply-To: X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2900.5579 This is a multi-part message in MIME format. ------=_NextPart_000_000C_01CA7DAE.5BD3D030 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: quoted-printable Al, no I do not measure "before and after"; it's measured at block = output near standard oil filter pedestal and is feed to PSRU input . see = attached (this photo shows the first cooler input, the pressure sender and the return line from second cooler) . if I understand the oil flow = correctly, this is after the coolers. My max oil pressure was 80 psi when I had one cooler and is still max 80 = psi with 2 coolers - typical operating pressure is 75 psi at 5500 rpm. Jeff Jeff; There is a bypass valve in the oil return circuit that regulates the max = oil pressure. That's probably setup for 80 psi in your engine. There is = also a pressure relief bypass just after the pump exit that is probably for 125 = psi (I forget what the stock one is). So conceivably the drop through the coolers could be 45 psi. =20 Not that it's a problem as long as there is sufficient flow to maintain = the regulated pressure. But it could be reducing the flow rate, which would reduce cooling capacity, and it could mean there is 125 psi in the lines from the engine; and to the cooler end tank. =20 The geared oil pump is (approximately) a positive displacement pump. It puts out 13-15 gpm at 5500 -6000 engine RPM. I just think it's a good = idea to know what sort of pressure drop your dealing with for any oil cooler = you put on your engine, other than the Mazda cooler. I still believe that = in the two oil cooler ruptures, and resulting in-flight fires that our = friend Chuck Harbert experienced, the pressure drop was a contributing factor. = He had three coolers in series, two up in the nose of a Velocity, along = with the concomitant lines and fittings. The first in the series was the one that ruptured both times. Undoubtedly running at the pump bypass = pressure (whatever that was), coupled with a little fatigue from vibrations in = the lines, and pressure ripple from the pump . . . well; just my opinion. =20 Al G =20 =20 ------=_NextPart_000_000C_01CA7DAE.5BD3D030 Content-Type: text/html; charset="us-ascii" Content-Transfer-Encoding: quoted-printable

Al, no I do not measure “before and after”; it’s measured = at block output near standard oil filter pedestal and is feed to PSRU input … see attached (this photo  shows the first  cooler = input, the pressure sender and the return line from second cooler) … if I = understand the oil flow correctly, this is after the coolers.

My max oil pressure was 80 psi when I had one cooler and is still max 80 = psi with 2 coolers – typical operating pressure is 75 psi at 5500 = rpm.

Jeff<= /font>

Jeff;

There is a bypass valve in the = oil return circuit that regulates the max oil pressure.  That’s = probably setup for 80 psi in your engine.  There is also a pressure relief = bypass just after the pump exit that is probably for 125 psi (I forget what the = stock one is).  So conceivably the drop through the coolers could be 45 = psi.

 

Not that it’s a problem as = long as there is sufficient flow to maintain the regulated pressure.  But = it could be reducing the flow rate, which would reduce cooling capacity, and it = could mean there is 125 psi in the lines from the engine; and to the cooler = end tank.

 

The geared oil pump is = (approximately) a positive displacement pump.  It puts out 13-15 gpm at 5500 -6000 = engine RPM.  I just = think it’s a good idea to know what sort of pressure drop your dealing with for any = oil cooler you put on your engine, other than the Mazda cooler.  I = still believe that in the two oil cooler ruptures, and resulting in-flight = fires that our friend Chuck = Harbert experienced, the pressure drop was a contributing = factor.  He had three coolers in series, two up in the nose of a Velocity, along with = the concomitant lines and fittings.  The first in the series was the one that = ruptured both times.  Undoubtedly running at the pump bypass pressure = (whatever that was), coupled with a little fatigue from vibrations in the lines, = and pressure ripple from the pump . . . well; just my = opinion.

 

Al G

 

 

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