Even though my engine now runs
cooler than I’d like at cruise and descent; I’m hesitant to put a thermostat
in the engine. Measurements I made on the dyno showed that installing
the thermostat reduced the coolant flow rate by nearly 1/3 (31%) at operating
conditions typical of climb. That would also reduce the cooling capacity
some, resulting in higher temps. I like that my coolant stays below
about 200 - 205 on climbout on a 90F day, so I don’t want to change
that.
The other factor of course is
that the engine would get up to 180F much quicker. As it is, I can start
up, listen to ATIS, take my time taxing between hangars, down to the runup
area, do the runup tests – and only then have the temp up to about 180.
It may get up to 190 by wheels up, but then it stabilizes during climb, and
will begin to drop as I reduce power.
The best way to increase cruise
temps is to reduce air flow.
I do have an in-line thermostat
in the line to my second radiator, but I had drilled a couple small holes to
insure some flow. I’m going to replace that with one with only the air
bleed hole, and see if the coolant temp stays at/above the 170 thermostat
temp.
Al G
-----Original Message-----
From: Rotary motors in
aircraft [mailto:flyrotary@lancaironline.net] On Behalf Of Steve
Brooks
Sent: Sunday, August 10, 2008 3:46 AM
To: Rotary
motors in aircraft
Subject: [FlyRotary] Re: 2nd flight on the new cooling
system
Paul,
That is a good point, and something that I had not
considered before. Putting the thermostat back in, wouldn't be an easy
task. I removed the plastic / fiber, whatever it is made of portion
where the thermostat resided, and used a 1/4" aluminum plate in it's
place. That plate has an AN16 fitting welded to it, and also has
two 1/4 NPT holes in it to hold sensors.
They probably make an in-line thermostat I assume, so
that would probably be an option.
Steve Brooks
-----Original Message-----
From: Rotary motors in aircraft
[mailto:flyrotary@lancaironline.net]On Behalf Of
fpbjr2001@yahoo.com
Sent: Saturday, August 09, 2008 7:40
PM
To: Rotary motors in aircraft
Subject: [FlyRotary] Re: 2nd flight on the new cooling
system
steve
sounds great. something to think about.
if get to a point where you think you have enough cooling a 170-180 degree
thermostat would be nice to stabilize the system. as you know i have run a
thermostat since day one.
paul brannon
--- On Sat, 8/9/08, Steve Brooks
<cozy4pilot@gmail.com> wrote:
> From: Steve Brooks
<cozy4pilot@gmail.com>
> Subject: [FlyRotary] 2nd flight on the new
cooling system
> To: "Rotary motors in aircraft"
<flyrotary@lancaironline.net>
> Date: Saturday, August 9, 2008,
1:58 PM
> I took the Cozy up this morning for the 2nd
flight on the
> new cooling
> system. The OAT was 3 or 4 degrees warmer
than the first
> flight, as it was
> 79 F when I took off.
> This time, I turned the cooling fan on while I
was taxiing
> out to the
> runway. After the taxi and pre-flight
checks, the oil was
> 135 F and the
> coolant was still reading pretty low. Maybe
115 to 120 or
> so. It is a
> little hard to read the analog gauge down on the
low end of
> the scale.
>
> I took off and climbed up to about 1300 FT AGL,
at which
> time I pulled the
> throttle back some and continued a cruise
climb. The
> coolant was showing
> about 190F, and I didn't think to check the
oil
> temperature. Oil
> temperature has not been my issue. It has
always been the
> coolant. The
> coolant temperature did still increase a little,
even at
> the reduced power,
> but just up to 200 F. I was close to a low
cloud layer at
> about 1800 AGL,
> so I throttle back some more and dropped the nose
to level
> flight. I also
> turned off the cooling fan to see what the
temperature
> would do on it's own.
> The temperature steadily dropped to about 180
degrees
> within just a few
> minutes, and then stabilized
there.
>
> I cruised around for a little while, flew over my
house and
> circled it once,
> and then headed back to the airport. With
the low cloud
> layer that had
> moved in, I really didn't know if it was going to
clear
> out or get thicker,
> so I flew the 5 minutes back to the airport, and
made a
> normal landing. As
> I was ready to throttle back to descend about 800
feet to
> pattern altitude,
> and quick check of the coolant temperature showed
about 160
> degrees. Not
> bad at all, although I was probably flying at
about 60%
> power. Still, it
> would have not been nearly that low before the
new cooling
> system.
>
> Once I landed and was clearing the runway, I
checked the
> temperatures again,
> and the coolant was less then 140 degrees after
the glide
> in to land. Since
> I planned to wash the plane, and sometimes it
starts hard
> after getting heat
> soaked sitting after a run, I turned on the
cooling fan
> while a taxied over
> to the where the wash area is. After
washing the plane, it
> started up
> pretty easily, so I guess that worked out
also.
>
> So far so good. I like what I see so far on
the radiator,
> and the cooling
> fan definitely gives me a lot more
options.
>
> Steve Brooks
> Cozy N75CZ
> 13B turbo to read the an
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