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I concur with Dave and Scott. At low to mid power
settings on the ground I can run indefinitely without overheating. Uncowled it
takes a long time for the temps to come up. Cowled the temps come up much
faster. But in neither case will the temps exceed around 180 on both coolant and
oil. You didn’t mention if the engine was cowled during the high power runs. If
so I recommend trying without the cowl installed if possible.
At full power settings on the ground and fully cowled
I've never run the engine more than about 15 minutes at a time, but for that run
time I still have not hit a red line on either oil or coolant. In flight at the
top of an 8000' climb from 525'MSL with a OAT on the ground of 95F my temps were
202 oil and 195 coolant. My typical cruise temps are 185 oil and 180 coolant. I
run a 180 degree thermostat.
I also concur with Bill's assessment of your oil cooler
ducting. The inlet looks reasonable to me but the outlet looks extremely
restrictive. Honestly I think you'd be better off eliminating it entirely and
just letting the exit air dump into the cowl to find its own way out. Just my
opinion. Hard to tell about the radiator ducting. What are your radiator core
dimensions?
Mike Wills
Sent: Saturday, April 17, 2010 9:49 PM
Subject: [FlyRotary] Re: cooling for ground runs
Thanks Scott,
You are right about what I said and I will
clarify a little. I say if it wont cool on the ground, it wont cool in the
air because when I first started flying I had marginal cooling on the ground and
marginal cooling in the air. At that time I could idle and taxi
indefinitely unless the OAT was above 85 or so, when my taxi times would be
limited to about 30 minutes. cooling in the air was similarly limited to
shallow climbs and less than full power in all but the coolest of
climates.
However, Chris may be talking about high power ground runs
which is a different story. A full 5 minutes at full power on the ground
is sure to push the limits of most installations, and a temporary spray bar fed
from a hose is a reasonable thought if you feel the need to do extended ground
runs at or near full power.
BTW Scott,
I just took another look at
your website and picture. You sure have done very nice workmanship.
I can't wait to see that thing fly! It is guaranteed to be one of the
fastest RV's around.
--
David Leonard
Turbo Rotary RV-6
N4VY
http://N4VY.RotaryRoster.net
http://RotaryRoster.net
On Sat, Apr 17, 2010 at 8:55 PM, <shipchief@aol.com> wrote:
Chris & Terria:
I had ground running temp issues at lower power. Dave Leonard told me
that it's important to get it to self cool at low to mid power on the ground.
He said that reliance on sufficient cooling when you come up to
flying speed most likely won't work if it won't self cool on the ground.
I took his advise and redesigned my cooling system, which by the way looks a
lot like yours with major differences being cooler ducting and cooler
orientation. He's a link to my page @ EAA326 site: http://gallery.eaa326.org/main.php?g2_itemId=1727Tracy
has commented that I should have reduced the cross section of my oil cooler
duct more quickly to force the air to uniformly pass thru the oil cooler core.
I applied that thinking to my water cooler which I built next, and it worked
even better than my cardboard and tape trial duct. What is the engine RPM and % load that you start to have cooling
problems?
Scott
-----Original Message----- From: Chris and Terria < candtmallory@embarqmail.com> To: Rotary motors in
aircraft < flyrotary@lancaironline.net> Sent: Sat, Apr 17, 2010
10:02 am Subject: [FlyRotary] cooling for ground runs
Gents,
I am doing the higher power ground runs now, and am only
able to run for about 5 minutes before reaching 195* or so. I’m looking
for ideas on how to extend the time for each ground run. I was thinking
of adding a spray bar like others have discussed. My thought was to
drill some holes in some PVC and connect it to the garden hose. Then put
it in the intake in front of the radiator. I would have to run the hose
out the front and clamp it down so it doesn’t come close to the prop.
I’m open to all ideas though.
I’ve attached a picture that shows my radiator and duct
work.
Thanks,
Chris
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