X-Junk-Score: 0 [] X-Cloudmark-Score: 0 [] X-Cloudmark-Analysis: v=2.2 cv=HLeBLclv c=1 sm=1 tr=0 a=Dd6vNLDtNqHqu7/G8ng+qg==:117 a=x7bEGLp0ZPQA:10 a=7mUfYlMuFuIA:10 a=ZR5kwuB734kA:10 a=pGLkceISAAAA:8 a=Ia-xEzejAAAA:8 a=eRLigfuSAAAA:8 a=3oc9M9_CAAAA:8 a=_6GpL_ENAAAA:8 a=BlJWoT8LAFpffIpN1kgA:9 a=MCmzpQuireFZ51BP:21 a=EbVoX1N4WH2jP7Dk:21 a=QEXdDO2ut3YA:10 a=CjxXgO3LAAAA:8 a=zX-4NEV-UZnUR0UV1MEA:9 a=yrTt53v7xuxhrFhv:21 a=0xhmzpIfzY8cHjkK:21 a=rhEL8z28GB3sKS_E:21 a=_W_S_7VecoQA:10 a=Urk15JJjZg1Xo0ryW_k8:22 a=BfhXYjFvZD4iae-mNffo:22 From: "Ernest Christley echristley@att.net" Received: from sonic306-23.consmr.mail.gq1.yahoo.com ([98.137.68.86] verified) by logan.com (CommuniGate Pro SMTP 6.2.5) with ESMTP id 11297821 for flyrotary@lancaironline.net; Sun, 24 Jun 2018 15:41:35 -0400 Received-SPF: none receiver=logan.com; client-ip=98.137.68.86; envelope-from=echristley@att.net DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=att.net; s=s1024; t=1529869261; bh=41T9AOO9bYDh1rF/Wd/9B08oZ0VyEg5NTlTI/zegyIw=; h=Date:From:Reply-To:To:In-Reply-To:References:Subject:From:Subject; b=lgfhhTjT8+pbNO4sWPtpOyoEcDlLiO6LZwgmOP5po3bdtUQZNWquLFLMHFqCHdjyXXK1yf6MeU+BiSdfezrAIGilP8bWSEwzKCsIzk7BhM4+tJIwt1oRBiAxKYfq+wywxmkaq070ommu5E3EQomyh2wPGWCIwzzK1lmPF1XaBEQ= X-YMail-OSG: uCZU45gVM1kp_cZ1KPH_Mmm5tcK3jOyYfkWftQBvf_4S7Mo2XD85aN7qhCL72kz QWTENGMpLHZghL8TZ_8dL.BLryafXoRYhvmm7XybXjNwVhHoVHgdE7C08oQuaYAV9nERg.ynG8tE 07F22BYO7QHsLrehJRV6y26ISfxX0sbqIsbAN8_S9KwMC8cUUnDSk0yVW28rS1GaOwYnjGR_EJD4 OdbXp3aLQs5H.7P_fhnOWr2Tgo609zrbje27DyhVwHl2AyFojX5iZP8xUkUTRDPwZbw3H4nTtlQz 7HgJq4mHfhTBFVDckYgXk0ZqJEY3mjt44Dde_gvL4ALtUnMicaf69vq9qJaLypBmhLN68EQXGjtm vBg3n0vMGYGsPx.mOQz6dDJ1PRxcrGSQwnS8drFvxX5ZyqLPv_JJckEtGtmmh6Y7Y1hs81r35se. FFgbDSJoA9RujA1LTZPqxqx1HeYf8B_nlJeYdlw0VtuHN0GGAow9ISGX1wZBNIeEAviurVyoyR4M AZzazkaoU3aPfpF7Ul9YNlXFia0mUThivc03YD8Ui5aXxaL0iOeZyIHTmxLN.Z1y6iXcXWXHIYBo 8pWKnF8EJt3gCuyKnK3VbEkhxt1O3Hw2bp07kn8simJBWdpi_128eXUGLXhar3IH32vHS6dPy8Bd g Received: from sonic.gate.mail.ne1.yahoo.com by sonic306.consmr.mail.gq1.yahoo.com with HTTP; Sun, 24 Jun 2018 19:41:01 +0000 Date: Sun, 24 Jun 2018 19:41:00 +0000 (UTC) Reply-To: Ernest Christley To: Rotary motors in aircraft Message-ID: <776901123.1650037.1529869260217@mail.yahoo.com> In-Reply-To: References: Subject: Re: [FlyRotary] Re: Oil MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_Part_1650036_1625186791.1529869260213" X-Mailer: WebService/1.1.12006 YahooMailNeo Mozilla/5.0 (X11; Ubuntu; Linux x86_64; rv:60.0) Gecko/20100101 Firefox/60.0 Content-Length: 22082 ------=_Part_1650036_1625186791.1529869260213 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable Isn't the opposite also true.=C2=A0 The most efficient removal of heat from= the back side of the rotor will occur when the oil is the coolest? I suspect that the actual system efficiency curve is very flat.=20 On Sunday, June 24, 2018 2:08 PM, "Charlie England ceengland7@gmail.com= " wrote: =20 First, let me say that I'm far from being an authority on this subject.= =C2=A0=20 =20 The idea of coolant (oil, water, air, etc) moving too quickly through a he= at exchanger comes up often. People who's opinion I trust (trained engineer= s) say that slowing flow does not improve efficiency. What I've been told i= s that yes, you may see higher delta T across the cooler with lower flow, b= ut that's not a true and complete picture of what's happening. My understan= ding, based on what I've read & been told, is that the best heat exchange o= ccurs with the max temperature difference between the media (oil>air, water= >air, etc). If you slow the flow through the exchanger, then yes, you will = see a bigger delta T across the exchanger, but that means that a lot of the= oil (in this case) in the exchanger has already been cooled 'early' in the= flow, so effectively, part of the exchanger is operating at a much lower t= emperature difference with the air, and therefore, its efficiency is reduce= d. So it follows that higher flow, keeping the entire exchanger hotter (low= er delta T) actually improves efficiency. Yes, it's counter-intuitive (at l= east for me). But supposedly, the most BTUs get removed from the system whe= n the entire exchanger is kept at close to the same temp across its face. =20 There's obviously a point of diminishing returns, where you're actually ad= ding heat by overpressurizing the flow path trying to speed up flow, but I = doubt we're there yet. :-) =20 Perhaps a real engineer could step in and clarify. =20 On 6/23/2018 9:35 PM, Andrew Martin andrew@martinag.com.au wrote: =20 Lynn, my setup is pretty much stock where most oil should pass through co= oler direct to rear iron ocv, only oil that enters oil gallery is filtered,= pressure, temp & redrive oil taken from a block after filter,=C2=A0 But th= e cooler issue is a bit more incidious in that without a pressure gauge at = pump outlet there is no indication of the restriction. I have no problem wi= th having =E2=80=9Csome=E2=80=9D restriction in the cooler but as it builds= markedly with increased flow at rpm, Oil delta t drops as oil flow is too = fast through the core to cool the oil, and when front cover relief opens at= high rpm due to the restriction, only part of pump output is getting coole= d and temps rise more. Setrab, Fluidyne etc do claim low pressure drop but= I have struggled to find at what flow rates, Adding smaller coolers in par= allel is an option but the data is still needed to choose the correct sizes= that allows all oil to pass through a cooler without pressure drop and hav= e just enough surface area to transfer heat to air. My test showed 140psi p= ump output 80psi at back iron, I still dont know what my front cover relief= is set at, as 140 was max pressure of gauge I had. But front cover relief = valve should never operate in normal operation as it is a safety valve for = the pump,front cover & cooler only. Only engine that is diferent is 2009+ r= enesis as that has only one valve in the system & diferent oil flow design = to the rest of the mazda rotaries.=20 Andrew=20 On Sun, 24 Jun 2018 at 7:51 am, Accountlehanover lehanover@aol.com wrote: =20 =C2=A0 A restrictive cooler would (might) show a higher oil pressure tha= n the control valve will allow if measured before the cooler. Because the s= tock relief valve is at=C2=A0 the end of the system. So the stock valve mig= ht allow for 80 PSI, but never open if the full 80 PSI never gets to it so = as to activate. Racers measure oil pressure where the oil enters the engin= e. Usually in an aluminum block that replaces the stock oil filter stand. What do the bearings see, is the information you want. We raced for years= with 80 PSI entering the engine. And that was turning the engine to 9,000 = RPM on each shift. Oil coolers are constructed of many sharp edged tubes . = Pushing oil or any liquid or gas into the end of a sharp edged tube is near= ly impossible. So many more tubes than you would calculate necessary are u= sed in order to overcome the sharp tube flow problem.=C2=A0 So, if the stoc= k relief were set at=C2=A079 PSI (stock on early engines) you would want to= see 79 PSI on you oil pressure Gage as taken out of that aluminum block. M= istral calculated the cooler size required on the test Piper. The plane wou= ld overheat the oil while still within sight of the airport. The were also using aircraft oil in the engine. 20-50 if I remember corre= ctly. So, flow got worse as the oil heated up. =20 The racer had an external oil pump with one pressure section (adjustable = up to any pressure you might want) and two scavenge sections. The scavenge = sections returned oil and air to a storage tank through a set of bug screen= filters and two Setrab 44 row coolers in series. The pressure section pul= led from the tank and pressurized oil went through two K&N oil filters in p= arallel and then through a single 44 row Setrab cooler. So, we ran 100 PSI = at the engine. Shifting at 9,700 RPM. 250 HP.=C2=A0 Oil is Red Line 20-50 = racing synthetic.=C2=A0 A common choice for rotary racing. Not a single oil= related failure in 30 years. Oil coolers (and filters) in parallel reduce = flow resistance. Coolers and filters in series increase flow resistance. Ra= cing oils collect heat and give it up more quickly than do conventional oi= ls.So any cooler performs a bit better with a synthetic.=20 Lynn E. Hanover lehanover@aol.com Any question, any time.=C2=A0 =20 =20 In a message dated 6/23/2018 4:59:30 AM Eastern Standard Time, flyrotary@= lancaironline.net writes:=20 =20 Just got around to plumbing in mechanical gauge before cooler to see what= s really happening with my oil flows, wish I=E2=80=99d done it years ago! = Learnt so much in a couple of minutes on things that I have wasted so much = time second guessing. my second attempt oil cooler did work better than the= original mazda cooler, but was atrocious overall, Pressure drop was about = 60psi at 1400 prop rpm. No wonder I cant cool the oil, bugger all is going= through it, just enough to give me about 80psi oil pressure. Ended up bypa= ssing cooler all together to confirm it is the cooler that is problem not l= ines or anything else, well what a diference pressures constant at 78psi a= t all rpm=E2=80=99s=20 Trouble is no cooler manufacturer here seems to have charts of flow & pre= ssure drop on their coolers, very frustrating especially as prices seem to = range between $100-900 for similar sizes, so makes it very hard to select c= orrect one. Andrew --=20 Regards Andrew Martin Martin Ag =20 =20 --=20 Regards Andrew Martin Martin Ag=20 =20 =20 | | Virus-free. www.avast.com | =20 =20 ------=_Part_1650036_1625186791.1529869260213 Content-Type: text/html; charset=UTF-8 Content-Transfer-Encoding: quoted-printable
Isn't the opposite also true.  The most efficie= nt removal of heat from the back side of the rotor will occur when the oil = is the coolest?

I suspect that the actual system efficiency= curve is very flat.


On Sunday, June 24, 2018 2:08 PM, "Char= lie England ceengland7@gmail.com" <flyrotary@lancaironline.net> wrote= :


=20 =20 =20
First, let me say that I'm = far from being an authority on this subject. 

The idea of coolant (oil, water, air, etc) moving too quickly through a heat exchanger comes up often. People who's opinion I trust (trained engineers) say that slowing flow does not improve efficiency. What I've been told is that yes, you may see higher delta T across the cooler with lower flow, but that's not a true and complete picture of what's happening. My understanding, based on what I've read & been told, is that the best heat exchange occurs with the max temperature difference between the media (oil>air, water>air, etc). If you slow the flow through the exchanger, then yes, you will see a bigger delta T across the exchanger, but that means that a lot of the oil (in this case) in the exchanger has already been cooled 'early' in the flow, so effectively, part of the exchanger is operating at a much lower temperature difference with the air, and therefore, its efficiency is reduced. So it follows that higher flow, keeping the entire exchanger hotter (lower delta T) actually improves efficiency. Yes, it's counter-intuitive (at least for me). But supposedly, the most BTUs get removed from the system when the entire exchanger is kept at close to the same temp across its face.

There's obviously a point of diminishing returns, where you're actually adding heat by overpressurizing the flow path trying to speed up flow, but I doubt we're there yet. :-)

Perhaps a real engineer could step in and clarify.

On 6/23/2018 9:35 PM, Andrew Martin andrew@martinag.= com.au wrote:
Lynn, my setup is pretty much stock where most oil should pass through cooler direct to rear iron ocv, only oil that enters oil gallery is filtered, pressure, temp & redrive oil taken from a block after filter, 
But the cooler issue is a bit more incidious in that without a pressure gauge at pump outlet there is no indication of the restriction. I have no problem with having =E2=80=9Csome=E2=80=9D restriction in the cooler but as it builds= markedly with increased flow at rpm, Oil delta t drops as oil flow is too fast through the core to cool the oil, and when front cover relief opens at high rpm due to the restriction, only part of pump output is getting cooled and temps rise more.
Setrab, Fluidyne etc do claim low pressure drop but I have struggled to find at what flow rates, Adding smaller coolers in parallel is an option but the data is still needed to choose the correct sizes that allows all oil to pass through a cooler without pressure drop and have just enough surface area to transfer heat to air.
My test showed 140psi pump output 80psi at back iron, I still dont know what my front cover relief is set at, as 140 was max pressure of gauge I had. But front cover relief valve should never operate in normal operation as it is a safety valve for the pump,front cover & cooler only.
Only engine that is diferent is 2009+ renesis as that has only one valve in the system & diferent oil flow design to the rest of the mazda rotaries.

Andrew

On Sun, 24 Jun 2018 at 7:51 am, Accountlehanover lehanover@ao= l.com <flyrota= ry@lancaironline.net> wrote:
  A restrictive cooler would (might) show a higher oil pressure than the control valve will allow if measured before the cooler. Because the stock relief valve is at  the end of the system. So the stock valve might allow for 80 PSI, but never open if the full 80 PSI never gets to it so as to activate. Racers measure oil pressure where the oil enters the engine. Usually in an aluminum block that replaces the stock oil filter stand.
What do the bearings see, is the information you want. We raced for years with 80 PSI entering the engine.=
And that was turning the engine to 9,000 RPM on each shift. Oil coolers are constructed of many sharp edged tubes . Pushing oil or any liquid or gas into the end of a sharp edged tube is nearly impossible. So many more tubes than you would calculate necessary are used in order to overcome the sharp tube flow problem.  So, if the stock relief were set at 79 PSI (stock on early engines) you would want to see 79 PSI on you oil pressure Gage as taken out of that aluminum block. Mistral calculated the cooler size required on the test Piper. The plane would overheat the oil while still within sight of the airport.
The were also using aircraft oil in the engine. 20-50 if I remember correctly. So, flow got worse as the oil heated up.

The racer had an external oil pump with one pressure section (adjustable up to any pressure you might want) and two scavenge sections. The scavenge sections returned oil and air to a storage tank through a set of bug screen filters and two Setrab 44 row coolers in series. The pressure section pulled from the tank and pressurized oil went through two K&N oil filters in parallel and then through a single 44 row Setrab cooler. So, we ran 100 PSI at the engine. Shifting at 9,700 RPM. 250 HP.  Oil is Red Line 20-50 racing synthetic. = A common choice for rotary racing. Not a single oil related failure in 30 years. Oil coolers (and filters) in parallel reduce flow resistance. Coolers and filters in series increase flow resistance. Racing oils collect heat and give it up more quickly than do conventional oils.So any cooler performs a bit better with a synthetic.

Lynn E. Hanover
Any question, any time. 


In a message dated 6/23/2018 4:59:30 AM Eastern Standard Time, flyrotary@lancaironline.net writes:

Just got around to plumbing in mechanical gauge before cooler to see whats really happening with my oil flows, wish I=E2=80=99d done it years ago! Learnt so much in a couple of minutes on things that I have wasted so much time second guessing. my second attempt oil cooler did work better than the original mazda cooler, but was atrocious overall, Pressure drop was about 60psi at 1400 prop rpm. No wonder I cant cool the oil, bugger all is going through it, just enough to give me about 80psi oil pressure.
Ended up bypassing cooler all together to confirm it is the cooler that is problem not lines or anything else, well what a diference pressures constant at 78psi at all rpm=E2= =80=99s

Trouble is no cooler manufacturer here seems to have charts of flow & pressure drop on their coolers, very frustrating especially as prices seem to range between $100-900 for similar sizes, so makes it very hard to select correct one.
Andrew
--
Regards Andrew Martin Martin Ag
--
Regards Andrew Martin Martin Ag


=09 =09=09 =09
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