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Yes, John, in the best of all possible worlds
a duct exiting the cooler would undoubtedly help. In fact, I attempted
that with my two GM radiator cores - BUT, by the time I had created the two
fiberglass ducts the constraints on their flow mandated by things like engine,
mounts, exhaust, etc, adversely affected the airflow to such a degree that they
actually hurt the cooling (in my case). If you have plenty of room and/or
a location for your cooler where you could avoid the twists and turns then
it may be worthwhile. I have a nose gear, so no way could I run a duct
straight back from my cooler. Also having a "plugs up" installation puts
my exhaust on the bottom also in the way.
In the long run, the oil temps are just fine dumping the
exit air under the cowling. That said - if you can round (2-3" dia)
(fiberglass? PVC pipe?) the bottom edge of your firewall (where the air exists)
that reportedly helps considerably by making it easier for air
to exit the cowl.
Ed A
----- Original Message -----
Sent: Tuesday, December 13, 2005 9:54
AM
Subject: [FlyRotary] Re: oil cooler
opening
Ed; Thanks for the numbers. Last
night I read the article in kit planes, Oct 99, by Barnaby Wainfan on duct
work and his article entitled wind tunnel said that you need a duct behind the
coolers to offset the drag of the air in the cowling. Has anyone done
any practical applications on this (for Mazdas), or is the air from the
coolant and oil radiators just dumped into the cowling. My very limited
understanding of this, tells me that drag means more fuel needed. Any
and all comments welcome. JohnD From the farm
----- Original Message -----
Sent: Monday, December 12, 2005 9:20
PM
Subject: [FlyRotary] Re: oil cooler
opening
John,
The area of my oil cooler opening is 22-24 sq inches
about 10" wide and 2 1/2" high. I don't have the exact dimension
handy, but its opening is approx 3-4" back of the prop flange. So far
its worked fine for about 5 RVs that I am aware of using this
approach.
Ed
----- Original Message -----
Sent: Monday, December 12, 2005 5:04
PM
Subject: [FlyRotary] oil cooler
opening
Ed; What is the opening area and the
distance behind the prop for the oil cooler inlet. I'm wondering if
the opening needs to be as near the prop as the inlets for the
radiators. Thanks in advance.
JohnD Had to cancel the insurance on
the ole Colt today and put comp. on - snowed in for the winter in northern
Michigan.
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