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Al,
I believe Rino said he had a fan on the oil
cooler, which I feel would be restrictive in aviation use, from what I've
heard. Might be good for taxiing etc.
I picked up this rule of thumb somewhere
that 600 cu" is good to 200 + Hp which gives 3cu" per HP for the radiator for
the rotary engine - so his 643 cu" is probably a little too large. Might be
good for extreme conditions.
I've also heard the Rotary oil rad is good
for 200+ hp - so that may imply a rule of thumb of ( 200 / 157
cu" ) .785 cu " per hp, for the rotary.
Works for me.
George ( down under)
Rino;
It seems very
peculiar that you get better oil cooling with the stock RX7 oil cooler than
the Griffin with more than
twice the core volume. Given the low exit air temp with the
Griffin cooler, one would
conclude something wrong on the oil side - flow was seriously limited; air
trapped in the cooler, maybe very poor flow distribution; something.
What is the core configuration of the Griffin – fin density,
tube configuration?
Al
The following info. might be of
interest to you, it has to do with my latest cooling system
experience.
I
ordered 2 Griffin radiators and
installed that, had to modify the air ducts
A water
radiator: no: GRI-2-58185-X
CROSSFLOW - DUAL
ROW 1-1/4" tubes
core
18" X 13" X 2.75" 234 sq. in. 643
cu. in.
A
custom made oil radiator no: CX-27256-01
core
18" X 7.5" X 2.75" 135 sq. in. 371 cu.
in.
added a
spall 10" fan (15 amp.) to the oil radiator
Still
not enough cooling, could not climb at full power for more than a few minutes
before the oil reached 220 deg. F.
I had nore than eough water
cooling, so I Built a oil/water
heat exchanger and added that in series with the
Griffin oil
rad.
That
did not work too well, not enough cooling.
Removed
the Griffin oil rad. and the
fan.
Replaced it with the
original RX7 oil radiator
core
17.5" X 4.5" X 2" 78 sq.
in. 157 cu. in.
Kept
the oil/water heat exchanger in series with the oil
rad.
Water
rad air in 84 sq. in. air out 180 sq.
in.
Oil rad
air in 40 sq. in. air out 54 sq.
in.
I think
this last system works --- finally
The
outside air temp is presently between 30 and 40 deg. F. so it is hard for me
to tell how it will work in the summer but the indications are
good. I had to plaster the front of the water rad. with duct tape
to raise the engine temp. and block the oil rad. air exit to reduce air
flow. The oil rad. air flow is reduced to 12 sq. in. at the moment and
not much air is flowing through the water rad.
I have
no water thermostat and no oil thermostat so I have to control the temp with
the air flow.
I need
to build vanes to control the air flow, that is what I am working on at the
moment.
I
consider this installation much simpler and easier to maintain. The
reason I figured that the griffin oil cooler was not working properly, the air
flow behind the rad. was not getting higher than abour 85 deg. F even
when the oil was at 220 de. F On the other hand the griffin water rad.
seems to work fine. Now the air flow temp behind both rads. goes to
about 130+ deg. F
A photo of the
present installation.
Renesis powered Glass
Goose
----- Original Message -----
Sent:
Thursday, October 29,
2009 1:19
AM
Subject:
[FlyRotary] Re: Tracy
RV8
Cooler weather
is helping now but still a work in progress. I'll write up a report
when the problem is fully solved.
Tracy
On Wed, Oct 28, 2009 at
6:56 PM, <stevei@carey.asn.au> wrote:
Hi
Tracy
Are you in a position to give us a further update on the
cooling of the RV8.
Thanks
Steve
Izett
Perth
Australia
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