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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!!!
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