X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Received: from mail-ww0-f50.google.com ([74.125.82.50] verified) by logan.com (CommuniGate Pro SMTP 5.3.11) with ESMTP id 4647214 for flyrotary@lancaironline.net; Sun, 19 Dec 2010 15:43:41 -0500 Received-SPF: pass receiver=logan.com; client-ip=74.125.82.50; envelope-from=rwstracy@gmail.com Received: by wwf26 with SMTP id 26so2193887wwf.7 for ; Sun, 19 Dec 2010 12:43:08 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=gamma; h=domainkey-signature:mime-version:received:sender:received :in-reply-to:references:date:x-google-sender-auth:message-id:subject :from:to:content-type; bh=cYYwT0QNkY9h5fu6NsuZwmYd9kl0GVIyMIFgHAu08mM=; b=aQrtFCjoKHWmdO4J65f/sWon70un67E4LKC/ejVvxKp1XeMmZXj5PCNTHxtbe2eg+O GlNfAR+Wbru0xu7PiGm/g/VaoPK4nUzWyEmmmWuNd2s0dAVakjG7GPrTK2Z+UN9Gox5J xvTTTH/2EYyGhnl5pY68+xWmhUiC4hGzvMKsw= DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=mime-version:sender:in-reply-to:references:date :x-google-sender-auth:message-id:subject:from:to:content-type; b=TsqITSHjuO1A8SY71vAhdGOMDg1vTZCIDf7vAziO4sTXeFMV3n33ID+K2ftxmFIttc u6NcKs3pvIX8nBt4qd4Ry3DB+ULiZke6Jvb1nTinKP0sRf8oW9DG/pZdED59aMVhgoj3 dh7RiG0v0XDKl94W+69r1OYLAYIo2PzFxGtAc= MIME-Version: 1.0 Received: by 10.216.187.133 with SMTP id y5mr3754993wem.110.1292791387936; Sun, 19 Dec 2010 12:43:07 -0800 (PST) Sender: rwstracy@gmail.com Received: by 10.216.200.158 with HTTP; Sun, 19 Dec 2010 12:43:07 -0800 (PST) In-Reply-To: References: Date: Sun, 19 Dec 2010 15:43:07 -0500 X-Google-Sender-Auth: 7-niwqA9dAKpXWL5-yygUnXjYq4 Message-ID: Subject: Re: [FlyRotary] Re: Fw: Water temps From: Tracy To: Rotary motors in aircraft Content-Type: multipart/alternative; boundary=0016365ee7247256800497c97384 --0016365ee7247256800497c97384 Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: quoted-printable Opps, did the rad size math in the "wrong direction". The rad would have t= o be *50%* bigger compared to what is needed with an air to oil cooler. Tracy On Sun, Dec 19, 2010 at 3:39 PM, Tracy wrote: > " > *no matter which leg of the coolant system you pick up the heat from the > oil cooler, you raise the temp of the coolant loop by the amount of > additional heat; so the rejection temp of the rad is higher either way."* > > > Not so fast! Here's my take on it. > > Yes, the *total *heat rejection of the rad has to end up being the > same. BUT with the cold side oil cooler, to keep the engine coolant inle= t > temperature (and temperature of the engine block) the same requires a 33% > larger rad (compared to what we needed a separate air to oil cooler). > Actually, the rad has to be even bigger than this because we have to have > the rad outlet temp even lower to compensate for the rise in coolant temp > due to temp rise of oil cooler. That means the median temp of the rad i= s > lower and therefore less efficient. > > If you cool the oil on the hot side of the coolant circuit, the inlet te= mp > of the rad is now higher than in the cold side scheme and the required ra= d > size and/or the airflow through the rad size increase is smaller due to t= he > higher delta T between air and rad. This results in less cooling drag. > > That's my story & I'm stick'n to it : ) > > Tracy > > On Sun, Dec 19, 2010 at 12:13 PM, Al Gietzen wrote: > >> For maximum cooling of the oil from an oil/water HX (heat exchanger) >> you=92ll want to plumb the oil from engine out to the cooler; and plumb = the >> cooler between the radiator and the engine return. And I=92m not quite = sure >> about Tracy=92s point because no matter which leg of the coolant system = you >> pick up the heat from the oil cooler, you raise the temp of the coolant = loop >> by the amount of additional heat; so the rejection temp of the rad is hi= gher >> either way. The assumption is, of course, that you have sufficient capa= city >> to keep the coolant exiting the engine below boiling for extended high >> power. >> >> >> >> On my Velocity 20B installation I have a primary radiator in the cowl, >> and a secondary in the wing root; plumbed in parallel. The wing root rad= has >> an in-line 170F thermostat, and generally only comes on line during exte= nded >> climb. No thermostat in the engine that would restrict flow and add a >> potential failure mode. >> >> >> >> I have an oil/air cooler and an oil/coolant HX, also plumbed in parallel= . >> The oil/coolant HX is plumbed to the exit of the primary rad. The oil t= emp >> runs about 20F higher than the coolant (measured at oil return and coola= nt >> out). I could probably reduce that difference by restricting flow to the >> oil/air cooler forcing more through the oil/coolant HX; but I=92m quite = happy >> with the way things work. >> >> >> >> Over 200 hours and lovin=92 my rotary more all the time. >> >> >> >> Al G >> >> >> >> ----- Forwarded Message ---- >> *From:* "CozyGirrrl@aol.com" >> *To:* keltro@att.net >> *Sent:* Mon, December 13, 2010 4:05:31 PM >> *Subject:* Re: Fw: [FlyRotary] Re: Fw: Water temps >> >> >> Thanks Tracy for the adjustment in my thinking. I don't want to target >> temps unrealistically. >> >> Where does that leave us with our pick up and return points for the >> oil/water cooling system? If the oil were being cooled with water only a= nd >> we wanted the best possible chance at that, wouldn't we want to feed it = the >> cooler water from the high pressure side of the pump prior to entering t= he >> block? >> >> >> >> Whatever space we would use for an oil/air cooler takes away from >> potential coolant radiator space. Putting the two side by side becomes l= ess >> efficient spacewise for both due to losses for structure etc. If it is n= ot >> possible to cool the oil adequately with water alone then we'll need to = back >> up a little and make other layout plans. I remember Richter's Cozy III w= ith >> three P-51 scoops, it got the job done but was like dragging a parachute= in >> drag. >> >> >> >> Kelly, to your comment below, while I am sure we'd have no problem putti= ng >> adequate heat into the oil, I am very concerned about keeping any more t= han >> just enough out of it. Much easier going one way then the other =3D) >> >> ...Chrissi >> >> >> >> In a message dated 12/13/2010 2:49:02 P.M. Central Standard Time, >> keltro@att.net writes: >> >> Chrissi, >> >> My own opinion is that after warm up and in flight the oil temp >> leaving the engine before the >> >> coolers (air or water to oil) will almost always be well above >> 160-180 F..............If it is not this >> >> high then the oil to water cooler will actually help warm it to a more >> efficient temp.........IMHO >> >> >> >> Somebody correct me if this is a fallacy !!.......................<:) >> >> >> >> Kelly Troyer >> *"DYKE DELTA JD2"** **(Eventually)* >> >> "13B ROTARY"_ Engine >> "RWS"_RD1C/EC2/EM2 >> "MISTRAL"_Backplate/Oil Manifold >> >> "TURBONETICS"_TO4E50 Turbo >> >> >> >> >> ------------------------------ >> >> *From:* "CozyGirrrl@aol.com" >> *To:* keltro@att.net >> *Sent:* Mon, December 13, 2010 12:52:06 PM >> *Subject:* Re: Fw: [FlyRotary] Re: Fw: Water temps >> >> This is where I get confused: >> >> >> >> said previously, >> >> -ideal water temp =3D 160*~180*F >> >> -ideal oil temp =3D 160*F >> >> >> >> If we are cooling oil with water that is at best hotter than the ideal >> temp of the oil, then are we not adding heat to it rather than removing = it? >> >> >> >> If we are trying to cool oil, why would we feed the highest temp water t= o >> the oil/water cooler rather than the coolest temp water by tapping into = the >> pump housing where it enters the block? >> >> >> >> Based on feedback, the water entering the block may be as low as >> 150*~160*F, would this be cool enough to do an adequate job of cooling t= he >> oil? >> >> >> >> Also, which model of Mocal is being used? >> >> >> >> ...Chrissi >> >> > --0016365ee7247256800497c97384 Content-Type: text/html; charset=windows-1252 Content-Transfer-Encoding: quoted-printable Opps, did the rad size math in the "wrong direction".=A0 The rad = would have to be 50% bigger compared to what is needed with an air t= o oil cooler.

Tracy

On Sun, Dec 19= , 2010 at 3:39 PM, Tracy <tracy@rotaryaviation.com> wrote:
"
no matter which leg of the coolant system you pick up the heat from the oil cooler, you raise the temp of the coolant loop by the amount of additional heat; so the rejection temp of the rad is higher either way."


Not so fast!=A0=A0 Here's my take on it.=A0=A0

Yes,=A0= =A0 the total heat rejection of the rad has to end up being the same= .=A0 BUT with the cold side oil cooler, to keep the engine coolant inlet te= mperature (and temperature of the engine block) the same requires a 33% lar= ger rad (compared to what we needed a separate air to oil cooler).=A0=A0 Ac= tually, the rad has to be even bigger than this because we have to have the= rad outlet temp even lower to compensate for the rise in coolant temp due = to temp rise of oil cooler.=A0=A0 That means the median temp of the rad is = lower and therefore less efficient.

If you cool the oil on the hot side of the coolant circuit,=A0 the inle= t temp of the rad is now higher than in the cold side scheme and the requir= ed rad size and/or the airflow through the rad size increase is smaller due= to the higher delta T between air and rad.=A0 This results in less cooling= drag.

That's my story & I'm stick'n to it : )

Tracy

On Sun, Dec 19, 2010 at 12:13 P= M, Al Gietzen <ALVentures@cox.net> wrote:

For maximum cooling of the oil from an oil/water HX (heat exchanger) you=92ll want to plumb the oil from engine out to the cooler; and plumb the cooler between the radiator and the engine return.=A0 And I=92m not quite sure about Tracy<= /font>=92s point because no matte= r which leg of the coolant system you pick up the heat from the oil cooler, you raise the temp of the coolant loop by the amount of additional heat; so the rejection temp of the rad is higher either way.=A0 The assumption is, of course, that you have sufficien= t capacity to keep the coolant exiting the engine below boiling for extended = high power.

=A0

On my Velocity<= /font> 20B installation I have a = primary radiator in the cowl, and a secondary in the wing root; plumbed in parallel. The wing root rad has an in-line 170F thermostat, and generally only comes on line during extended c= limb. No thermostat in the engine that would restrict flow and add a potential fa= ilure mode.

=A0

I have an oil/air cooler and an oil/coolant HX, also plumbed in parallel. The oil/coolant HX is plumbed to the exit of the primary rad. =A0The oil temp runs about 20F higher than the coolant (measured at oil return and coolant out). I could probably reduce that difference by restricting flow to the oil/air cooler forcing more through the oil/coolant HX; but I=92m quite happy with the way things work.=A0

=A0

Over 200 hours and lovin=92 my rotary more all the time.

=A0

Al G

=A0=

----- Forw= arded Message ----
From: "CozyGirrrl@ao= l.com" <CozyGirrrl@aol.com>
To: keltro@att.net
Sent: Mon, December 13, 2010 4:05:31 PM
Subject: Re: Fw: [FlyRotar= y] Re: Fw: Water temps


Thanks Tracy for the adj= ustment in my thinking. I don't want to target temps unrealistically.

Where does that leave us with our pick up and return points for the oil/water coo= ling system? If the oil were being cooled with water only and we wanted the best possible chance at that, wouldn't we want to feed it the cooler water f= rom the high pressure side of the pump prior to entering the block?

=A0

Whatever space we would use for an oil/air cooler takes away from potential coolant radiator space. Putting the two side by side becomes less efficient spacewi= se for both due to losses for structure etc. If it is not possible to cool the= oil adequately with water alone then we'll need to back up a little and mak= e other layout plans. I remember Richter's Cozy III with three P-51 scoops, it = got the job done but was like dragging a parachute in drag.

=A0

Kelly, to your comment below, while I am sure we'd have no problem putting ade= quate heat into the oil, I am very concerned about keeping any more than just eno= ugh out of it. Much easier going one way then the other =3D)

...Chrissi

=A0

In a message dated 12/13/2= 010 2:49:02 P.M. Central Standard Time, keltro@att.net writes:

Chrissi,

=A0=A0=A0 My own opinion is that after warm up and in flight the oil temp leaving the engine before the

coolers (air or water=A0 to oil) will almost always be well above 160-180=A0F..............If it is not this

high then the=A0oil to water cooler will actually help warm it to a more efficient temp.........IMHO

=A0

=A0=A0 Somebody correct me if this is a fallacy !!.......................<:)

=A0

K= elly Troyer
"DYKE DE= LTA JD2"<= span style=3D"font-family: Arial; color: black;"> = (Eventually)<= /b>

&= quot;13B ROTARY"_ Engine
"RWS"_RD1C/EC2/EM2
"MISTRAL"_Backplate/Oil Manifold

&= quot;TURBONETICS"_TO4E50 Turbo

=A0

=A0

From: &q= uot;CozyGirrrl@aol.= com" <C= ozyGirrrl@aol.com>
To: keltro@att.net
Sent: Mon, December 13, 2010 12:52:06 PM
Subject: Re: Fw: [FlyRotar= y] Re: Fw: Water temps

This is where I get confused:

=A0

said previously,

-ideal water temp =3D 160*~180*F

-ideal oil temp =3D 160*F

=A0

If we are cooling oil with water that is at best hotter than the ideal temp of th= e oil, then are we not adding heat to it rather than removing it?

=A0

If we are trying to cool oil, why would we feed the highest temp water to the oil/water cooler rather than the coolest temp water by tapping into the pum= p housing where it enters the block?

=A0

Based on feedback, the water entering the block may be as low as 150*~160*F, woul= d this be cool enough to do an adequate job of cooling the oil?=

=A0

Also, which model of Mocal is being used?

=A0

...Chrissi



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