Return-Path: Received: from wb1-a.mail.utexas.edu ([128.83.126.134] verified) by logan.com (CommuniGate Pro SMTP 4.2.1) with ESMTP-TLS id 401052 for flyrotary@lancaironline.net; Tue, 07 Sep 2004 15:50:55 -0400 Received-SPF: none receiver=logan.com; client-ip=128.83.126.134; envelope-from=msteitle@mail.utexas.edu Received: (qmail 25629 invoked from network); 7 Sep 2004 19:50:26 -0000 Received: from dhcp-191-101.per.utexas.edu (HELO hrs-mark.mail.utexas.edu) (146.6.191.101) by wb1.mail.utexas.edu with SMTP; 7 Sep 2004 19:50:26 -0000 Message-Id: <5.1.1.5.2.20040907144459.01c322c8@localhost> X-Sender: msteitle@mail.utexas.edu@localhost X-Mailer: QUALCOMM Windows Eudora Version 5.1.1 Date: Tue, 07 Sep 2004 14:50:19 -0500 To: "Rotary motors in aircraft" From: Mark Steitle Subject: Re: [FlyRotary] Re: Photos of Core tanks internals In-Reply-To: Mime-Version: 1.0 Content-Type: multipart/alternative; boundary="=====================_7828890==.ALT" --=====================_7828890==.ALT Content-Type: text/plain; charset="us-ascii"; format=flowed Ed, I was wondering if there might be holes on the outer edges that I couldn't see. So there are 2/3 more holes than can be seen in the pictures. Obviously, there's enough flow to do the job. Also, I noticed on the second picture there appears to be a hole or two that appear to be plugged. I would surely want to be certain that my system is thoroughly flushed when using a/c cores (especially used ones) so as to prevent blockage of these small holes. Mark S. At 01:37 PM 9/7/2004 -0400, you wrote: >Actually, Mark, there are 5 holes , three toward the center that are easy >to see in the photos and two at the extreme sides of the tanks. Yes, at >first glance, you would think no-way it would cool - heck you wouldn't >even flow much coolant through it. But a 1" dia hose only has 0.785 >inches of area. > > Surprisingly the total area of these small holes adds up to between > 0.83 and 1.93 sq inches (holes appear to be between 1/8 - 3/16" in dia) - > more than you would think. So certainly a lot of loss with so many small > holes, but if the 1.93 sq inch area is close to their total area then > they are probably as effective at flowing coolant as a 1" hose with 0.785 > sq inches. > > This is one I successfully flew with before the stress of the heavy > AN-16 fittings hanging off the 90 deg fitting cause it to spring a small leak. > >Ed > >Ed Anderson >RV-6A N494BW Rotary Powered >Matthews, NC >----- Original Message ----- >From: Mark Steitle >To: Rotary motors in aircraft >Sent: Tuesday, September 07, 2004 1:06 PM >Subject: [FlyRotary] Re: Photos of Core tanks internals > >Ed, >What is amazing to me is that there are only three small holes in each >cross-tube. Its hard to believe that these small holes will pass enough >coolant to cool a 13B @ WOT. > >Mark S. > > > >At 12:38 PM 9/7/2004 -0400, you wrote: >>Well, David, I just went down to the shop through the pouring remnants of >>Frances and cut open each side tank of a core I had taken from the junkyard >>years ago. >> >>The photos are attached and speak for themselves - no dividers or other >>impediments to coolant flow in the tanks - pretty clean channel from top to >>bottom. Each "row" has 5 approx 1/8" (perhaps slightly larger) dia holes >>that conduct the water through the core to the opposite side tank. So 14 >>rows * 5 * area of 1/8-3/16" dia hole would give a cross flow channel area >>of around 0.86 sq inches to 1.93 sq inches - probably toward the larger >>figure. >> >>So as Bill suggested they may have redesigned the heat exchangers to take a >>different approach to recondensing the refrigerant calling for the divider >>plate. Given the relatively small cross channels, it is my opinion that a >>serpentine cooler is probably offering considerably more resistance to flow. >>Some of the radiator shop webpages give an estimate of the increase in flow >>resistance of a Serpentine core over the straight through - as best I recall >>it was something like 4 times as best I recall. >> >>So, its clear that not all GM evaporator cores are created the same way. >>This one was from the an late 80s early 90s Cadillac. I looked all over for >>some identifying model number but could not find anything. I do recall it >>had a yellow sticker with a black C on it when I yanked it. >> >>In any case, it looks like we can not simply order just any GM cooler core. >>I suspect that when they switched over to the more environmental friendly >>refrigerant then there could have been some redesign of the core, but just >>speculation on my part. >> >>Here's the photos >> >>Ed. >> >> >> >>Ed Anderson >>RV-6A N494BW Rotary Powered >>Matthews, NC >>----- Original Message ----- >>From: "David Carter" >>To: "Rotary motors in aircraft" >>Sent: Tuesday, September 07, 2004 11:55 AM >>Subject: [FlyRotary] Re: Water pump problem >> >> >> >> > Thanks, Ed. >> > >> > I wonder Steve Brooks's core with a "plate" is different from the >> > GM/Harrison cores that I have (Chev'y Caprice). >> > - When I probed my core last night and found no plates in the end cap >> > with the larger of the two welded tubes, I DIDN'T check the other side - >> > those smaller 1/2" OD tubes turn 90 degrees and run about a foot, so I >>never >> > probed that side. That is the side that has the little "filter" and/or >> > "expansion jet" thing sitting about an inch down inside. Perhaps there's >>a >> > plate on that side that matches what has been discussed recently. >> > >> > If Steve's core is a typical GM/Harrison core, then I'd like to >> understand >> > more about which end "the plate" is in and tell us more about "the tube >>that >> > was removed". I've not yet cut into any of my cores to mod the fittings, >>so >> > am ignorant of the insides. >> > >> > David >> > >> > ----- Original Message ----- >> > From: "Ed Anderson" >> > To: "Rotary motors in aircraft" >> > Sent: Tuesday, September 07, 2004 6:54 AM >> > Subject: [FlyRotary] Re: Water pump problem >> > >> > >> > > Hey, David, not to worry. We have all hit the "Send" button on an e >>mail >> > or >> > > two and later wondered why we did. {:>) >> > > >> > > Ed >> > > >> > > Ed Anderson >> > > RV-6A N494BW Rotary Powered >> > > Matthews, NC >> > >> > >> > >> > >> Homepage: http://www.flyrotary.com/ >> > >> Archive: http://lancaironline.net/lists/flyrotary/List.html >> > >> >> >> >> >> >> >> Homepage: http://www.flyrotary.com/ >> >> Archive: http://lancaironline.net/lists/flyrotary/List.html --=====================_7828890==.ALT Content-Type: text/html; charset="us-ascii" Ed,
I was wondering if there might be holes on the outer edges that I couldn't see.  So there are 2/3 more holes than can be seen in the pictures.  Obviously, there's enough flow to do the job.  Also, I noticed on the second picture there appears to be a hole or two that appear to be plugged.  I would surely want to be certain that my system is thoroughly flushed when using a/c cores (especially used ones) so as to prevent blockage of these small holes.

Mark S.

At 01:37 PM 9/7/2004 -0400, you wrote:
Actually, Mark, there are 5 holes , three toward the center that are easy to see in the photos and two at the extreme sides of the tanks. Yes, at first glance, you would think no-way it would cool - heck you wouldn't even flow much coolant through it.  But a 1" dia hose only has 0.785 inches of area.
 
 Surprisingly the  total area of these small holes  adds up to between 0.83 and 1.93 sq inches (holes appear to be between 1/8 - 3/16" in dia) - more than you would think.  So certainly a lot of loss with so many small holes, but if the 1.93 sq inch area is close to their total area then they are probably as effective at flowing coolant as a 1" hose with 0.785 sq inches.
 
 This is one I successfully flew with before the stress of the heavy AN-16 fittings hanging off the 90 deg fitting cause it to spring a small leak.
 
Ed
 
Ed Anderson
RV-6A N494BW Rotary Powered
Matthews, NC
----- Original Message -----
From: Mark Steitle
To: Rotary motors in aircraft
Sent: Tuesday, September 07, 2004 1:06 PM
Subject: [FlyRotary] Re: Photos of Core tanks internals

Ed,
What is amazing to me is that there are only three small holes in each cross-tube.  Its hard to believe that these small holes will pass enough coolant to cool a 13B @ WOT. 

Mark S.



At 12:38 PM 9/7/2004 -0400, you wrote:
Well, David,  I just went down to the shop through the pouring remnants of
Frances and cut open each side tank of a core I had taken from the junkyard
years ago.

The photos are attached and speak for themselves - no dividers or other
impediments to coolant flow in the tanks - pretty clean channel from top to
bottom.  Each "row" has 5 approx 1/8" (perhaps slightly larger) dia holes
that conduct the water through the core to the opposite side tank.  So 14
rows * 5 * area of 1/8-3/16" dia hole would give a cross flow channel area
of around 0.86 sq inches to 1.93 sq inches - probably toward the larger
figure.

So as Bill suggested they may have redesigned the heat exchangers to take a
different approach to recondensing the refrigerant calling for the divider
plate.  Given the relatively small cross channels, it is my opinion that a
serpentine cooler is probably offering considerably more resistance to flow.
Some of the radiator shop webpages give an estimate of the increase in flow
resistance of a Serpentine core over the straight through - as best I recall
it was something like 4 times as best I recall.

So, its clear that not all GM evaporator cores are created the same way.
This one was from the an late 80s early 90s Cadillac.  I looked all over for
some identifying model number but could not find anything.  I do recall it
had a yellow sticker with a black C on it when I yanked it.

In any case, it looks like we can not simply order just any GM cooler core.
I suspect that when they switched over to the more environmental friendly
refrigerant then  there could have been some redesign of the core, but just
speculation on my part.

Here's the photos

Ed.



Ed Anderson
RV-6A N494BW Rotary Powered
Matthews, NC
----- Original Message -----
From: "David Carter" <dcarter@datarecall.net>
To: "Rotary motors in aircraft" <flyrotary@lancaironline.net>
Sent: Tuesday, September 07, 2004 11:55 AM
Subject: [FlyRotary] Re: Water pump problem



> Thanks, Ed.
>
> I wonder Steve Brooks's core with a "plate" is different from the
> GM/Harrison cores that I have (Chev'y Caprice).
>     - When I probed my core last night and found no plates in the end cap
> with the larger of the two welded tubes, I DIDN'T check the other side -
> those smaller 1/2" OD tubes turn 90 degrees and run about a foot, so I
never
> probed that side.  That is the side that has the little "filter" and/or
> "expansion jet" thing sitting about an inch down inside.  Perhaps there's
a
> plate on that side that matches what has been discussed recently.
>
> If Steve's core is a typical GM/Harrison core, then I'd like to understand
> more about which end "the plate" is in and tell us more about "the tube
that
> was removed".  I've not yet cut into any of my cores to mod the fittings,
so
> am ignorant of the insides.
>
> David
>
> ----- Original Message -----
> From: "Ed Anderson" <eanderson@carolina.rr.com>
> To: "Rotary motors in aircraft" <flyrotary@lancaironline.net>
> Sent: Tuesday, September 07, 2004 6:54 AM
> Subject: [FlyRotary] Re: Water pump problem
>
>
> > Hey, David, not to worry.  We have all hit the "Send" button on an e
mail
> or
> > two and later wondered why we did. {:>)
> >
> > Ed
> >
> > Ed Anderson
> > RV-6A N494BW Rotary Powered
> > Matthews, NC
>
>
>
> >>  Homepage:  http://www.flyrotary.com/
> >>  Archive:   http://lancaironline.net/lists/flyrotary/List.html
>





>>  Homepage:  http://www.flyrotary.com/
>>  Archive:   http://lancaironline.net/lists/flyrotary/List.html
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