X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Received: from EXHUB003-4.exch003intermedia.net ([207.5.74.111] verified) by logan.com (CommuniGate Pro SMTP 5.3c3) with ESMTPS id 4023518 for flyrotary@lancaironline.net; Wed, 16 Dec 2009 09:08:11 -0500 Received-SPF: none receiver=logan.com; client-ip=207.5.74.111; envelope-from=jwhaley@datacast.com Received: from EXVMBX003-5.exch003intermedia.net ([207.5.74.45]) by EXHUB003-4.exch003intermedia.net ([207.5.74.111]) with mapi; Wed, 16 Dec 2009 06:07:32 -0800 From: Jeff Whaley To: Rotary motors in aircraft Date: Wed, 16 Dec 2009 06:08:40 -0800 Subject: RE: [FlyRotary] Re: Oil cooler Thread-Topic: [FlyRotary] Re: Oil cooler Thread-Index: Acp98XcIFmrCu2cTTomXLc0RLsqU8wAXgEfA Message-ID: References: In-Reply-To: Accept-Language: en-US Content-Language: en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: acceptlanguage: en-US Content-Type: multipart/alternative; boundary="_000_C03ABB0A7362B84BB53D544B3C305E0E0153A4A103BDEXVMBX0035e_" MIME-Version: 1.0 --_000_C03ABB0A7362B84BB53D544B3C305E0E0153A4A103BDEXVMBX0035e_ Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: quoted-printable AL, Thanks for your explanations, there are some intricate details about the Ma= zda engine that I am either unaware of or don't fully understand. I wasn't aware that the engine out pressure could be 125 psi with the retur= n regulated to 80 psi. According to the feedback from Fluidyne the coolers= are pressure-tested to 300 psi. My oil cooling capacity has increased tre= mendously so the flow rate through the coolers must be good; I DID check al= l lines after a brief engine run, post-install to ensure no leaks and that = all lines were hot (that was my low-tech flow test). One thing I have noticed after installing the second oil cooler, is the oil= pressure gauge has some fluctuation or bounce at 5500 rpm that wasn't ther= e with only one cooler (Mazda or First Fluidyne), so there is a difference,= but again I'm not sure why. It is something that I'll continue to monitor= - we are still flying local. Jeff From: Rotary motors in aircraft [mailto:flyrotary@lancaironline.net] On Beh= alf Of Al Gietzen Sent: Tuesday, December 15, 2009 8:45 PM To: Rotary motors in aircraft Subject: [FlyRotary] Re: Oil cooler Al, no I do not measure "before and after"; it's measured at block output n= ear standard oil filter pedestal and is feed to PSRU input ... see attached= (this photo shows the first cooler input, the pressure sender and the re= turn line from second cooler) ... if I understand the oil flow correctly, t= his is after the coolers. My max oil pressure was 80 psi when I had one cooler and is still max 80 ps= i 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 oi= l pressure. That's probably setup for 80 psi in your engine. There is als= o a pressure relief bypass just after the pump exit that is probably for 12= 5 psi (I forget what the stock one is). So conceivably the drop through th= e 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 r= educe cooling capacity, and it could mean there is 125 psi in the lines fro= m the engine; and to the cooler end tank. The geared oil pump is (approximately) a positive displacement pump. It pu= ts out 13-15 gpm at 5500 -6000 engine RPM. I just think it's a good idea t= o 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 t= he two oil cooler ruptures, and resulting in-flight fires that our friend C= huck 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 t= he concomitant lines and fittings. The first in the series was the one tha= t ruptured both times. Undoubtedly running at the pump bypass pressure (wh= atever that was), coupled with a little fatigue from vibrations in the line= s, and pressure ripple from the pump . . . well; just my opinion. Al G --_000_C03ABB0A7362B84BB53D544B3C305E0E0153A4A103BDEXVMBX0035e_ Content-Type: text/html; charset="us-ascii" Content-Transfer-Encoding: quoted-printable

AL,

Thanks for your explanations, there are some intricate detai= ls about the Mazda engine that I am either unaware of or don’t fully understand.

I wasn’t aware that the engine out pressure could be 1= 25 psi with the return regulated to 80 psi.  According to the feedback fr= om Fluidyne the coolers are pressure-tested to 300 psi.  My oil cooling capacity has increased tremendously so the flow rate through the coolers mu= st be good; I DID check all lines after a brief engine run, post-install to en= sure no leaks and that all lines were hot (that was my low-tech flow test).=

One thing I have noticed after installing the second oil coo= ler, is the oil pressure gauge has some fluctuation or bounce at 5500 rpm that w= asn’t there with only one cooler (Mazda or First Fluidyne), so there is a differe= nce, but again I’m not sure why.  It is something that I’ll continue to monitor - we are still flying local.

Jeff

 

From: Rotary motors= in aircraft [mailto:flyrotary@lancaironline.net] On Behalf Of Al Gietze= n
Sent: Tuesday, December 15, 2009 8:45 PM
To: Rotary motors in aircraft
Subject: [FlyRotary] Re: Oil cooler

 

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 a= nd the return line from second cooler) … if I understand the oil flow correctly, this is after the coolers.

My max oil pressure was 8= 0 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 regulate= s 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 ex= it 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 fl= ow 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 p= si 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 th= ink 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 no= se of a Velocity, along with the concomitant lines and fittings.  The fir= st in the series was the one that ruptured both times.  Undoubtedly runni= ng at the pump bypass pressure (whatever that was), coupled with a little fati= gue from vibrations in the lines, and pressure ripple from the pump . . . well; just my opinion.

 

Al G

 

 

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