|
Mark,
That is some serious power alright, close enough is
right.
George ( down under)
George,
Yes, my Fluidyne cooler should easily do the job of cooling my current
engine. But I am building a P-port 20B to replace this motor
downstream, so I need to design for 375hp (375 x .8 = 300). The Fluidyne
cooler is 297 cu in (core size is 9 x 11 x 3). Close enough for
government work.
Mark
On Mon, Dec 14, 2009 at 5:48 PM, George Lendich <lendich@aanet.com.au>
wrote:
Sorry Mark,
It's hard to keep track of who's running what,
on a 20B or say 300 +hp, two would still be too much, but you know
that already, as you said your running too cool. One of your coolers is more
than a stock 13B cooler by about 14 cu"
Do you or anyone know the size of the
stock 20B oil cooler?
Just playing with the figures, I guess I could
use .8 or .85 cu" per Hp for oil cooling, just as a linear
calculation. Using .8 , Mark's need for 300hp is only 240cu", however
each oil cooler is 189cu" ea. This area required may need to increase
incrementally with increased HP.
Anyone with any suggestions in regard to
this?
George (down under)
George,
Keep in mind that I have a 50% greater cooling requirement than a
13B.
Mark
On Mon, Dec 14, 2009 at 3:51 PM, George Lendich
<lendich@aanet.com.au> wrote:
Mark/ Jeff,
I hadn't bothered to check the size before
as the Mazda oil cooler is known to be more than adequate. If your using
over the Mazda size in cu" then your over sized. Both
your cooler areas are well over sized. I seen one chap used two Mazda
coolers when taking off on water using NOs, but he admitted it was over
cooling.
George ( down under)
George,
I'm not at the hangar today, but off the top of my head, they are
about 4 1/2 x 18 x 2. I had considered using two RX-7
coolers arranged in a wedge configuration. But I ended
up going with a large rectangular unit which I chose because
the air would not have to change directions to get through
the core. Hopefully, that would provide lower cooling
drag.
Mark
On Mon, Dec 14, 2009 at 1:50 PM, George Lendich
<lendich@aanet.com.au> wrote:
Mark /Jeff,
What is the Mazda cooler size., in
comparison?
George ( down under)
----- Original Message -----
Sent: Tuesday, December 15,
2009 3:34 AM
Subject: [FlyRotary] Re: Oil
Cooling
Jeff,
I doubt an air lock is/was the problem as it was oriented
with the inlet/outlet on the side. If there was an air
lock, I would think that at least part of the other end tank would
get warm (which it doesn't). Good suggestion though.
This single cooler is almost twice the size as one of your
coolers. So, it should be up to the task at hand. This
is assuming that it is working as designed.
Mark
On Mon, Dec 14, 2009 at 11:20 AM, Jeff
Whaley <jwhaley@datacast.com> wrote:
Hey Mark, I guess the
only other logical reason would be an air-lock caused by
orientation … but if you’ve got two exactly the same, that is
highly unlikely.
Incidentally, I have
two, 6.25”x11”2.75” oil coolers in series – I’m over-cooled with
2 but found 1 wasn’t enough.
JWW
From: Rotary motors in aircraft [mailto:flyrotary@lancaironline.net] On Behalf Of
Mark Steitle
Sent: Monday, December 14, 2009 12:00
PM
To: Rotary motors in aircraft
Subject:
[FlyRotary] Oil Cooling
Well guys, here is a new one... at least for
me.
I've never been able to get my 20B oil
temps quite low enough for comfort.
I chaulked most of it up to the high Texas temps
and an engine that produces gobs of horsepower (just kidding on
the "gobs of horsepower" part). I'm running a 10" x
11" x 2 3/4" Fluidyne dual-pass oil/air cooler and a large
(and heavy) Fluidyne oil/water exchanger. Water temps
were fine but the oil temps would reach 240*-245* on climb,
and just barely down to 200* in cruise. I tried different
plumbing arrangements, added a cowl flap (which helped some),
etc. Still, the temps didn't want to come
down. Well, yesterday I ran the engine with the
cowl off (doing some fuel pressure monitoring/adjusting),
and I had just finished getting things up to operating
temperature, verified that fuel pressure was good, and then
shut it down. I just happened to touch the end tank
on the Fluidyne oil/air exchanger and to my surprise, IT
WAS STONE COLD! I touched the other end (inlet/outlet) and
it was HOT! I thought this was odd.
The only thing that I could figure is that the dual-pass oil
cooler was defective. Since the cooler has no thermostat,
I can only conclude that the internal tank separator, which
is how they make a single-pass cooler into a
dual-pass cooler, was allowing the oil to bypass
the core and go directly from the inlet to the
outlet. Well, no wonder I can't get the oil temps to
come down!!!
I replaced the cooler with another
unit I had on hand, ran the engine, and low and
behold, both end tanks come up to temp together.
I did a couple of ground runs and themps look
encouraging. But unfortunately, it was too late
to do a test flight yesterday. I'm sure the new
cooler will make a big improvement. I'm
hoping it will be enough to permit me to remove the
oil/water exchanger.
Moral of the story... DON'T TAKE ANYTHING FOR
GRANTED! TRUST BUT VERIFY!!!
|