|
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 -----
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
|