X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Received: from na01-bn1-obe.outbound.protection.outlook.com ([207.46.163.153] verified) by logan.com (CommuniGate Pro SMTP 6.0.8) with ESMTPS id 6747813 for flyrotary@lancaironline.net; Mon, 24 Feb 2014 20:45:10 -0500 Received-SPF: none receiver=logan.com; client-ip=207.46.163.153; envelope-from=SBoese@uwyo.edu Received: from BL2PR05MB098.namprd05.prod.outlook.com (10.255.232.15) by BL2PR05MB067.namprd05.prod.outlook.com (10.255.232.22) with Microsoft SMTP Server (TLS) id 15.0.883.10; Tue, 25 Feb 2014 01:44:32 +0000 Received: from BL2PR05MB098.namprd05.prod.outlook.com ([169.254.2.165]) by BL2PR05MB098.namprd05.prod.outlook.com ([169.254.2.165]) with mapi id 15.00.0883.010; Tue, 25 Feb 2014 01:44:32 +0000 From: "Steven W. Boese" To: Rotary motors in aircraft Subject: wastegate control and oil coolers Thread-Topic: wastegate control and oil coolers Thread-Index: AQHPMcn71nQaKSSRi0un60j6N+OrWA== Date: Tue, 25 Feb 2014 01:44:31 +0000 Message-ID: References: In-Reply-To: Accept-Language: en-US Content-Language: en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: x-originating-ip: [70.196.193.67] x-forefront-prvs: 01334458E5 x-forefront-antispam-report: SFV:NSPM;SFS:(10009001)(979002)(6009001)(377454003)(189002)(199002)(86362001)(92566001)(47446002)(74316001)(74662001)(94946001)(95416001)(74502001)(31966008)(54356001)(94316002)(53806001)(74366001)(54316002)(76482001)(33646001)(83322001)(19580405001)(2656002)(16236675002)(19580395003)(83072002)(95666003)(81686001)(80976001)(63696002)(74706001)(87266001)(51856001)(81816001)(46102001)(85306002)(50986001)(85852003)(79102001)(47976001)(59766001)(49866001)(77982001)(47736001)(81342001)(65816001)(66066001)(80022001)(69226001)(87936001)(81542001)(74876001)(77096001)(76786001)(75432001)(76796001)(56776001)(56816005)(93136001)(90146001)(93516002)(4396001)(76576001)(24736002)(80792004)(19607625005)(969003)(989001)(999001)(1009001)(1019001);DIR:OUT;SFP:1101;SCL:1;SRVR:BL2PR05MB067;H:BL2PR05MB098.namprd05.prod.outlook.com;CLIP:70.196.193.67;FPR:ECF7F2E5.A7F2DF80.B0F03577.4EE0DC4C.2057E;PTR:InfoNoRecords;MX:1;A:1;LANG:en; Content-Type: multipart/alternative; boundary="_000_d74079f297074ddebc06c73f2cdab666BL2PR05MB098namprd05pro_" MIME-Version: 1.0 X-OriginatorOrg: uwyo.edu --_000_d74079f297074ddebc06c73f2cdab666BL2PR05MB098namprd05pro_ Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: quoted-printable Bobby, The wastegate control with the used Malibu variable absolute pressure contr= oller seems to work fine. I didn't use the butterfly type wastegate but ma= de a linkage from the Malibu actuator to the poppet valve type wastegate. = The wastegate is closed until the upper deck pressure reaches the value req= uired by the controller. Having the wastegate closed even when boost is no= t required doesn't seem to be a problem since BSFC of close to 0.50 was obs= erved at 23-30" MAP. Oil cooling is another story. Above 2800 RPM, with a single RX7 cooler, oi= l is bypassing the cooler either through the relief valve at the oil pump o= r the relief valve in the oil cooler, depending on the engine series. If t= he oil bypass occurs at the oil pump, the temperature of the oil returning = from the cooler is often acceptable (210 degrees or less). If the oil bypa= ss occurs in the oil cooler, the temperature of the oil returning from the = cooler is higher due to the mixing of the hot bypassed oil with the oil tha= t has been cooled. The 13B has a relief valve at the oil pump and one at the flywheel iron. W= ith a stock relief valve in the flywheel iron, the oil bypass occurs mostly= within the oil cooler so keeping the oil returning from it at an acceptabl= e temperature is more of a challenge. If the flywheel iron relief valve pr= essure were to be increased, some or all of the bypassed oil would be bypas= sed at the oil pump (front cover relief valve) instead, making it easier to= keep the reduced flow of oil returning from the cooler at an acceptable te= mperature. With the 2009 or newer Renesis that is on the engine test stand now,, there= is no relief valve in the flywheel iron and the oil pressure downstream of= the cooler is normally over 100 psi. As a result, the oil is bypassed at = the oil pump, which makes keeping the oil returning from the RX7 cooler at = an acceptable temperature less of a challenge. I haven't worked with the pre-2009 Renesis, but that engine does not have a= relief valve at the oil pump and does have one at the flywheel iron. So a= t RPM greater than around 2800, oil will be bypassing within the RX7 cooler= regardless of the flywheel iron relief valve pressure setting, with the re= sultant challenge of maintaining acceptable temperatures of the oil returni= ng from the cooler. The behavior of the oil cooling systems described above is just due to the = hydraulics of the systems. Add to this the effects of ducting and airspeed= which affect the air pressure differential across the oil cooler core, and= things get pretty complicated -- for me, at least. When measuring the tem= perature of the oil coming out of the oil pump going to the oil cooler, I d= idn't like the over 270 degree values I saw. I also didn't like the oil pr= essures over 150 psi in the same location. As a result, I am working on fi= nding an oil cooler solution that does not have the high resistance to oil = flow of the RX7 cooler. The intent is enable all of the oil to pass throug= h the cooler and not require such high oil pressures coming out of the oil = pump. It also requires that more heat be dissipated since now all of the o= il is being cooled instead of just some of it. With a single stock RX7 oil cooler, oil would bypass at the oil pump at abo= ut 2800 RPM. Acceptable oil temperatures (210 degrees) returning from the = cooler were maintained at 30" Hg MAP on a 55 degree day with 5" H20 air pre= ssure across the core. The next thing I tried was to use an AC evaporator core like the two used a= s coolant radiators. On the surface using one of these as an oil cooler mi= ght seem to be reasonable since it is usually accepted that one third of th= e heat rejected by the cooling systems is to be handled by the oil cooler. = With the AC core, the oil flow resistance was such that oil was not bypass= ing at the oil pump at 5600 RPM, but the oil temperature returning from it = was too high. It appeared that acceptable oil temperatures would be mainta= ined at 30" Hg MAP on a 25 degree day with 5" H20 air pressure across the c= ore. Then two stock RX7 oil coolers were connected in parallel. They both still= had their thermostats installed. With this configuration, oil would bypas= s at the oil pump at about 4800 RPM. It appeared that acceptable oil tempe= ratures would be maintained at 30" Hg MAP on an 85 degree day with 5" H20 a= ir pressure across the cores. The two RX7 oil coolers were then converted to single pass which required r= emoving the thermostats and welding oil line connections to the normally un= connected end tanks. These coolers were connected in parallel. Oil would = bypass at the oil pump at about 5600 RPM. It appeared that acceptable oil = temperatures would be maintained at 30" Hg MAP on an 85 degree day with 5" = H20 air pressure across the cores. After consultation with Fluidyne technical support, a used DB-30517 oil coo= ler was obtained from an Ebay source. When received, the part # stamped o= n it was DB-30517M and the core dimensions were 9 1/2" X 5 3/4" X 2 1/2" in= stead of the expected 11 1/2" X 5 3/4" X 2 1/2". The cooler appeared to be= clean inside and undamaged. With this cooler installed, oil was not bypas= sing at the oil pump at 5600 RPM (oil psi there was 140). It appeared that= acceptable oil temperatures would be maintained at 30" Hg MAP on a 35 degr= ee day with 5" H20 air pressure across the core. This performance was cons= iderably less than expected even considering the smaller core volume, both = in terms of the oil temperatures achieved and the high oil pressure drop ac= ross the cooler. A Fluidyne DB-30617 oil cooler has been obtained and is ready to test. Cor= e dimensions are 11 1/2" X 9 1/2" X 2 1/2". It looks like the DB-30717 oil cooler that you have is what I might end up = with. I will just have had a lot more "fun" getting to that point. At lea= st trying things on the test stand is a lot easier than modifying the plane= each time. Steve ________________________________ From: Rotary motors in aircraft on behalf of = Bobby J. Hughes Sent: Monday, February 24, 2014 7:55 AM To: Rotary motors in aircraft Subject: [FlyRotary] Re: duct shape Steve, How is you test stand engine running? Any progress with oil cooling and was= te gate control? Bobby --_000_d74079f297074ddebc06c73f2cdab666BL2PR05MB098namprd05pro_ Content-Type: text/html; charset="us-ascii" Content-Transfer-Encoding: quoted-printable

Bobby,

 

The wastegate control with the used Malibu variable absolute pressu= re controller seems to work fine.  I didn't use the butterfly type was= tegate but made a linkage from the Malibu actuator to the poppet valve type= wastegate.  The wastegate is closed until the upper deck pressure reaches the value required by the controller. = ; Having the wastegate closed even when boost is not required doesn't seem = to be a problem since BSFC of close to 0.50 was observed at 23-30" MAP= .

 

Oil cooling is another story.  Above 2800 RPM, with a single RX7 co= oler, oil is bypassing the cooler either through the relief valve at t= he oil pump or the relief valve in the oil cooler, depending on the engine = series.  If the oil bypass occurs at the oil pump, the temperature of the oil returning from the cooler is often accept= able (210 degrees or less).  If the oil bypass occurs in the oil coole= r, the temperature of the oil returning from the cooler is higher due to th= e mixing of the hot bypassed oil with the oil that has been cooled. 

 

The 13B has a relief valve at the oil pump and one at the flywheel = iron.  With a stock relief valve in the flywheel iron, the oil by= pass occurs mostly within the oil cooler so keeping the oil returning from = it at an acceptable temperature is more of a challenge.  If the flywheel iron relief valve pressure were to be increased, some= or all of the bypassed oil would be bypassed at the oil pump (front c= over relief valve) instead, making it easier to keep the reduced flow = of oil returning from the cooler at an acceptable temperature. 

 

With the 2009 or newer Renesis that is on the engine test stand now,, th= ere is no relief valve in the flywheel iron and the oil pressure downstream= of the cooler is normally over 100 psi.  As a result, the oil is bypa= ssed at the oil pump, which makes keeping the oil returning from the RX7 cooler at an acceptable temperature less of= a challenge.

 

I haven't worked with the pre-2009 Renesis, but that engine does not hav= e a relief valve at the oil pump and does have one at the flywheel iro= n.  So at RPM greater than around 2800, oil will be bypassing within t= he RX7 cooler regardless of the flywheel iron relief valve pressure setting, with the resultant challenge of mainta= ining acceptable temperatures of the oil returning from the cooler.

 

The behavior of the oil cooling systems described above is ju= st due to the hydraulics of the systems.  Add to this the effects of d= ucting and airspeed which affect the air pressure differential ac= ross the oil cooler core, and things get pretty complicated -- for me, at least.  When measuring the temperature of the oil comin= g out of the oil pump going to the oil cooler, I didn't like the over 270 d= egree values I saw.  I also didn't like the oil pressures over 150 psi= in the same location.  As a result, I am working on finding an oil cooler solution that does not have the high resi= stance to oil flow of the RX7 cooler.  The intent is enable = all of the oil to pass through the cooler and not require such high oil pre= ssures coming out of the oil pump.  It also requires that more heat be dissipated since now all of the oil is being cooled inst= ead of just some of it.

 

With a single stock RX7 oil cooler, oil would bypa= ss at the oil pump at about 2800 RPM.  Acceptable oil temperatures&nbs= p;(210 degrees) returning from the cooler were maintained at 30" Hg MA= P on a 55 degree day with 5" H20 air pressure across the core.

 

The next thing I tried was to use an AC evaporator core= like the two used as coolant radiators.  On the surface using one of = these as an oil cooler might seem to be reasonable since it is usually acce= pted that one third of the heat rejected by the cooling systems is to be handled by the oil cooler.  With the AC = core, the oil flow resistance was such that oil was not bypassing at the oi= l pump at 5600 RPM, but the oil temperature returning from it was too = high.  It appeared that acceptable oil temperatures would be maintained at 30" Hg MAP on a 25 degree day with 5"= ; H20 air pressure across the core.

 

Then two stock RX7 oil coolers were connected in parallel.  They bo= th still had their thermostats installed.  With this configuration, oi= l would bypass at the oil pump at about 4800 RPM.  It appeared that ac= ceptable oil temperatures would be maintained at 30" Hg MAP on an 85 degree day with 5" H20 air pressure acr= oss the cores.

 

The two RX7 oil coolers were then converted to single pass which require= d removing the thermostats and welding oil line connections to the normally= unconnected end tanks.  These coolers were connected in parallel.&nbs= p; Oil would bypass at the oil pump at about 5600 RPM.  It appeared that acceptable oil temperatures would be main= tained at 30" Hg MAP on an 85 degree day with 5" H20 air pre= ssure across the cores.

      

After consultation with Fluidyne technical support, a used DB-= 30517 oil cooler was obtained from an Ebay  source.  When receive= d, the part # stamped on it was DB-30517M and the core dimensions were 9 1/= 2" X 5 3/4" X 2 1/2" instead of the expected = 11 1/2" X 5 3/4" X 2 1/2".  The cooler appeared to be clean= inside and undamaged.  With this cooler installed, oil was not bypass= ing at the oil pump at 5600 RPM (oil psi there was 140).  It appe= ared that acceptable oil temperatures would be maintained at 30" Hg MA= P on a 35 degree day with 5" H20 air pressure across the core.&nbs= p; This performance was considerably less than expected even considering th= e smaller core volume, both in terms of the oil temperatures achieved and t= he high oil pressure drop across the cooler.

 

A Fluidyne DB-30617 oil cooler has been obtained and is ready to t= est.  Core dimensions are 11 1/2" X 9 1/2" X 2 1/2"= ;.

 

It looks like the DB-30717 oil cooler that you have is what I migh= t end up with.  I will just have had a lot more "fun" gettin= g to that point.  At least trying things on the test stand is a lot ea= sier than modifying the plane each time.

 

Steve

 

 

 

 

  

 

 

 

From: Rotary motors in ai= rcraft <flyrotary@lancaironline.net> on behalf of Bobby J. Hughes <= ;bhughes@qnsi.net>
Sent: Monday, February 24, 2014 7:55 AM
To: Rotary motors in aircraft
Subject: [FlyRotary] Re: duct shape
 

Steve,

 

How is you test stand= engine running? Any progress with oil cooling and waste gate control?

 

Bobby

 

 

 

 

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