From: "Steven W. Boese" <flyrotary@lancaironline.net>
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To: Rotary motors in aircraft <flyrotary@lancaironline.net>
Subject: Re: [FlyRotary] oil cooling
Thread-Topic: [FlyRotary] oil cooling
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Date: Thu, 23 Mar 2017 16:23:33 +0000
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Andrew,


When the RX7 oil cooler thermostat warms up, it moves a spring loaded disk =
against the bypass port outlet which tries to force all the oil to flow thr=
ough the core.  If the pressure differential across the core exceeds about =
50 psi, the spring loaded disk lifts and allows oil to bypass the core.  Th=
e oil thermostat not closing properly and oil bypassing due to pressure rel=
ief would be identical in terms of how the oil passes through the system.  =
I don't know if a Cosmo oil cooler has the same function.


Using the temperature of the oil returning to the engine from the oil coole=
r as the criteria for oil cooling effectiveness, this oil temperature will =
be higher when hot oil bypassing in the cooler is mixed with the cooler oil=
 that has passed through the core.  If the oil pressure difference across t=
he core is less than 50 psi, all of the oil returning to the engine will ha=
ve passed through the core and its temperature will be lower even though th=
e amount of heat removed from the oil system could be the same in both case=
s.


With the Fluidyne oil cooler the pressure drop through it didn't exceed 15 =
psi under any condition that I tested (up to 6500 RPM).  The pressure drop =
through the RX7 cooler was about 80 psi  when the front cover relief valve =
(1986 13B ) opened at 150 psi.  Oil passing through the cooler at this poin=
t was flowing both through the core and the thermostat relief passage.  I c=
annot find any reference to a relief valve in the front cover of a 2004-200=
8 Renesis.  If this is the case, then the oil pressure at the inlet to an R=
X7 cooler must be far in excess of 150 psi under high RPM operation (over 2=
500 RPM).


Of course this discussion of oil flow is only part of the oil cooling story=
.  Air flow through the core and the core construction are major factors, t=
oo.


Steve Boese

________________________________
From: Rotary motors in aircraft <flyrotary@lancaironline.net> on behalf of =
Andrew Martin <flyrotary@lancaironline.net>
Sent: Thursday, March 23, 2017 12:51:22 AM
To: Rotary motors in aircraft
Subject: [FlyRotary] oil cooling


Steve, searched the archives, always seems a tricky process for me for some=
 reason. filter of OIL and search Steven W. Boese worked.  I had missed tha=
t discussion on oil coolers. certainly could explain my oil overheating pro=
blem. Thanks for documenting your findings.
I have a 2004 Renesis in the plane and used the oil heat exchanger from an =
70000km Cosmo that I pulled a factory 20b from.
You said worst case for cooling was when oil was not at pump (front cover) =
relief pressure and was bypassing in the cooler, I didn't realise the mazda=
 cooler had pressure relief or do you think the oil thermostat was not clos=
ing properly?
So, off to get a new oil heat exchanger.

Andrew




On Thu, Mar 23, 2017 at 12:11 PM, Steven W. Boese <flyrotary@lancaironline.=
net<mailto:flyrotary@lancaironline.net>> wrote:

Andrew,


A Fluidyne DB-30618 is the oil cooler I ended up with in the plane.


When a pressure gauge was installed in the line between the front cover out=
let and the RX7 oil cooler inlet, the pressure rose with increasing RPM to =
150 psi at 2800 RPM.  Increasing RPM above 2800 resulted in a steady pressu=
re at 150 psi.  Since the oil pump is a positive displacement pump, additio=
nal oil flow above 2800 RPM passes through the relief valve into the sump. =
 At 5600 RPM half of the oil pumped by the oil pump never flows through the=
 oil cooler.


With the Fluidyne oil cooler, the pressure at its inlet never reaches 150 p=
si so all of the oil passes through it.


An archive search for 25 Feb 2014 should find a description of various oil =
cooler configurations that I tested.


Steve Boese


________________________________
From: Rotary motors in aircraft <flyrotary@lancaironline.net<mailto:flyrota=
ry@lancaironline.net>> on behalf of Andrew Martin <flyrotary@lancaironline.=
net<mailto:flyrotary@lancaironline.net>>
Sent: Wednesday, March 22, 2017 8:40:08 PM
To: Rotary motors in aircraft
Subject: [FlyRotary] Re: fuel system peer review


This thread has perfect timing and great info for me.

I was thinking of ditching my setup and simplifying it, but it looks like e=
very system is a compromise.
I just mounted a belly radiator which entailed moving the pumps & sump tank=
. As other local pilots had commented on how complex my fuel system was I t=
hought it opportune to address it now. After following this thread though I=
'm inclined to stick with this setup now as I know it works. and just not l=
et anyone else on the controls.
Only problem I have is I cannot tell the fuel level in the sump tank. Need =
some sort of warning that I've drained a tank dry or have a vent or feed pr=
oblem. Am thinking of putting a sight glass in the return line from sump to=
 fuel selectors for a visual clue.
I like this setup as it allows me to feed from any or all tanks. not needed=
 but usually leave 1 transfer pump on. if both transfer pumps happened to f=
ail the fuel return path gives a free flow path from tanks to sump also.
I have managed to empty the sump tank once when flow testing the system but=
 there was no back pressure on the system so regulator was not circulating =
fuel. I guessed the tank vent lines (1/4") are just to small when fuel flow=
ing at 180l/hr and it vapourized in the sump.

Steve. I'm interested to know the model No. of your fluidyne oil cooler. I =
started with these mods because I couldn't control my oil temps, so new bel=
ly radiator installed to give oil cooler all the cowl air, but I never thou=
ght that the mazda cooler may be blocking oil flow. Whats the clue that the=
 front relief valve is opening?

Andrew



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<html>
<head>
<meta http-equiv=3D"Content-Type" content=3D"text/html; charset=3Dus-ascii"=
>
</head>
<body>
<style type=3D"text/css" style=3D"display:none;"><!-- P {margin-top:0;margi=
n-bottom:0;} --></style>
<div id=3D"divtagdefaultwrapper" style=3D"font-size:12pt;color:#000000;font=
-family:Calibri,Arial,Helvetica,sans-serif;" dir=3D"ltr">
<p>Andrew,</p>
<p><br>
</p>
<p>When the RX7 oil cooler thermostat warms up, it moves a spring loaded di=
sk against the bypass port outlet which tries to force all the oil to flow =
through the core.&nbsp; If the pressure differential across the core exceed=
s about 50 psi, the spring loaded disk
 lifts and allows oil to bypass the core.&nbsp; The oil thermostat not clos=
ing properly and oil bypassing due to pressure relief would be identical&nb=
sp;in terms of&nbsp;how the oil passes through the system.&nbsp; I don't kn=
ow if a Cosmo oil cooler has the same function.</p>
<p><br>
</p>
<p>Using the temperature of the oil returning to the engine from the oil co=
oler as the criteria for oil cooling effectiveness, this oil temperature wi=
ll be higher when hot oil bypassing in the cooler is mixed with the cooler =
oil that has passed through the
 core.&nbsp; If the oil pressure&nbsp;difference across the core is less th=
an 50 psi,&nbsp;all of the oil returning to the engine will have passed thr=
ough the core and its temperature will&nbsp;be&nbsp;lower even though the a=
mount of heat removed from the oil system&nbsp;could be the same
 in both cases.</p>
<p><br>
</p>
<p>With the&nbsp;Fluidyne oil cooler the pressure drop through&nbsp;it didn=
't exceed 15 psi&nbsp;under any condition that I tested (up to 6500 RPM).&n=
bsp; The pressure drop through the RX7 cooler was about 80 psi&nbsp; when t=
he&nbsp;front cover relief valve (1986 13B )&nbsp;opened at 150 psi.&nbsp;
 Oil passing through the cooler at this point was flowing both through the =
core and the thermostat relief passage.&nbsp; I cannot find any reference t=
o a relief valve in the front cover of a 2004-2008 Renesis.&nbsp; If this i=
s the case, then the oil pressure&nbsp;at the inlet
 to an RX7 cooler must be far in excess of 150 psi under high RPM operation=
 (over 2500 RPM).</p>
<p><br>
</p>
<p>Of course&nbsp;this discussion of oil flow is only&nbsp;part of&nbsp;the=
 oil cooling story.&nbsp; Air flow through the core and the core constructi=
on are major factors, too.&nbsp;</p>
<p><br>
</p>
<p>Steve Boese&nbsp;&nbsp; <br>
</p>
</div>
<hr style=3D"display:inline-block;width:98%" tabindex=3D"-1">
<div id=3D"divRplyFwdMsg" dir=3D"ltr"><font face=3D"Calibri, sans-serif" st=
yle=3D"font-size:11pt" color=3D"#000000"><b>From:</b> Rotary motors in airc=
raft &lt;flyrotary@lancaironline.net&gt; on behalf of Andrew Martin &lt;fly=
rotary@lancaironline.net&gt;<br>
<b>Sent:</b> Thursday, March 23, 2017 12:51:22 AM<br>
<b>To:</b> Rotary motors in aircraft<br>
<b>Subject:</b> [FlyRotary] oil cooling</font>
<div>&nbsp;</div>
</div>
<div>
<div dir=3D"ltr"><br>
<div class=3D"gmail_extra">Steve, searched the archives, always seems a tri=
cky process for me for some reason. filter of OIL and search Steven W. Boes=
e worked.&nbsp; I had missed that discussion on oil coolers. certainly coul=
d explain my oil overheating problem. Thanks
 for documenting your findings.<br>
</div>
<div class=3D"gmail_extra">I have a 2004 Renesis in the plane and used the =
oil heat exchanger from an 70000km Cosmo that I pulled a factory 20b from.
<br>
You said worst case for cooling was when oil was not at pump (front cover) =
relief pressure and was bypassing in the cooler, I didn't realise the mazda=
 cooler had pressure relief or do you think the oil thermostat was not clos=
ing properly?<br>
</div>
<div class=3D"gmail_extra">So, off to get a new oil heat exchanger.<br>
</div>
<div class=3D"gmail_extra"><br>
</div>
<div class=3D"gmail_extra">Andrew <br>
</div>
<div class=3D"gmail_extra">
<div>
<div class=3D"gmail_signature" data-smartmail=3D"gmail_signature"><br>
<br>
<br>
</div>
</div>
<br>
<div class=3D"gmail_quote">On Thu, Mar 23, 2017 at 12:11 PM, Steven W. Boes=
e <span dir=3D"ltr">
&lt;<a href=3D"mailto:flyrotary@lancaironline.net" target=3D"_blank">flyrot=
ary@lancaironline.net</a>&gt;</span> wrote:<br>
<blockquote class=3D"gmail_quote" style=3D"margin:0 0 0 .8ex;border-left:1p=
x #ccc solid;padding-left:1ex">
<div>
<div id=3D"m_8706385816750161470divtagdefaultwrapper" style=3D"font-size:12=
pt;color:#000000;font-family:Calibri,Arial,Helvetica,sans-serif" dir=3D"ltr=
">
<p></p>
<p>Andrew,</p>
<p><br>
</p>
<p>A Fluidyne DB-30618 is t<span>he oil cooler I ended up with in the plane=
.</span></p>
<p><br>
</p>
<p>When a pressure gauge was installed in the line between the front cover =
outlet and the RX7 oil cooler inlet, the pressure rose with increasing RPM =
to 150 psi at 2800 RPM.&nbsp; Increasing RPM above 2800 resulted in a stead=
y pressure at 150 psi.&nbsp; Since the oil
 pump is a positive displacement pump, additional oil flow <span>above 2800=
</span> RPM passes through the relief valve into the sump.&nbsp; At 5600 RP=
M half of the oil pumped by the oil pump never flows through the oil cooler=
.</p>
<p><br>
</p>
<p>With the Fluidyne oil cooler, the pressure at its inlet never reaches 15=
0 psi so all of the oil passes through it.</p>
<p><br>
</p>
<p>An archive search for 25 Feb 2014 should find a description of various o=
il cooler configurations that I tested.</p>
<p><br>
</p>
<p>Steve Boese</p>
<br>
<p></p>
</div>
<hr style=3D"display:inline-block;width:98%">
<div id=3D"m_8706385816750161470divRplyFwdMsg" dir=3D"ltr"><font style=3D"f=
ont-size:11pt" face=3D"Calibri, sans-serif" color=3D"#000000"><b>From:</b> =
Rotary motors in aircraft &lt;<a href=3D"mailto:flyrotary@lancaironline.net=
" target=3D"_blank">flyrotary@lancaironline.net</a>&gt;
 on behalf of Andrew Martin &lt;<a href=3D"mailto:flyrotary@lancaironline.n=
et" target=3D"_blank">flyrotary@lancaironline.net</a>&gt;<br>
<b>Sent:</b> Wednesday, March 22, 2017 8:40:08 PM<span class=3D""><br>
<b>To:</b> Rotary motors in aircraft<br>
<b>Subject:</b> [FlyRotary] Re: fuel system peer review</span></font>
<div>&nbsp;</div>
</div>
<div>
<div dir=3D"ltr">
<div>
<div>
<div>
<div>
<div>
<div>
<div>
<div><br>
</div>
<div>
<div class=3D"h5">This thread has perfect timing and great info for me.<br>
<br>
</div>
</div>
</div>
<div>
<div class=3D"h5">I was thinking of ditching my setup and simplifying it, b=
ut it looks like every system is a compromise.
<br>
</div>
</div>
</div>
<div>
<div class=3D"h5">I just mounted a belly radiator which entailed moving the=
 pumps &amp; sump tank. As other local pilots had commented on how complex =
my fuel system was I thought it opportune to address it now. After followin=
g this thread though I'm inclined to stick
 with this setup now as I know it works. and just not let anyone else on th=
e controls.<br>
</div>
</div>
</div>
<div>
<div class=3D"h5">Only problem I have is I cannot tell the fuel level in th=
e sump tank. Need some sort of warning that I've drained a tank dry or have=
 a vent or feed problem. Am thinking of putting a sight glass in the return=
 line from sump to fuel selectors
 for a visual clue.<br>
</div>
</div>
</div>
<div>
<div class=3D"h5">I like this setup as it allows me to feed from any or all=
 tanks. not needed but usually leave 1 transfer pump on. if both transfer p=
umps happened to fail the fuel return path gives a free flow path from tank=
s to sump also.<br>
</div>
</div>
</div>
<div>
<div class=3D"h5">I have managed to empty the sump tank once when flow test=
ing the system but there was no back pressure on the system so regulator wa=
s not circulating fuel. I guessed the tank vent lines (1/4&quot;) are just =
to small when fuel flowing at 180l/hr and
 it vapourized in the sump.<br>
<br>
</div>
</div>
</div>
<div>
<div class=3D"h5">Steve. I'm interested to know the model No. of your fluid=
yne oil cooler. I started with these mods because I couldn't control my oil=
 temps, so new belly radiator installed to give oil cooler all the cowl air=
, but I never thought that the mazda
 cooler may be blocking oil flow. Whats the clue that the front relief valv=
e is opening?<br>
<br>
</div>
</div>
</div>
Andrew<br>
<div><br>
</div>
</div>
</div>
</div>
</blockquote>
</div>
<br>
</div>
</div>
</div>
</body>
</html>

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