Jerry Hey wrote:

After  months of pondering, I ordered a Scirroco style double pass
(Griffin) from Summit Racing.  Price was $285.00.  Two row 1.25
tubes.  The core size is 22 x 13 x 2.5 for 715  cu in.
The  fuselage installation will include a  small fan  for ground ops.
Inlet ducting will be a combination of parallel sided submerged
inlets and scoops.  These will be aluminum sheet metal. Easy to build
and, if necessary, to discard.   The idea is to get good cooling with
minimal scoops.   The submerged inlets (two)  will be 6" sq. for a
total of 72 sq in. This meets the one fourth rule for scoop size. The
covering scoops are additional.   The covering scoops will start at
three inches high  and will be adjusted up or down until the system
works.  I have drawn in 4 inch scoops and they don't look bad. Two
inch scoops are very fast and racy looking.   It is a balancing act
between adequate cooling and low drag.

The submerged inlets will have relatively  short steep ramps that
would never work on their own.  Their job is to add capacity to the
scoops.

I think the Scirroco double pass rad would be ideal for under  engine
installations since both the inlet and outlets are on the same end.
----Jerry

Good luck Jerry :-) It is always nice to have someone confirm
the laws of physics by breaking them :-)

Too bad you already bought
the rad. I came up with an idea early this morning at the hanger
for you. I was going to suggest two low air flow resistance one inch
thick rads in V formation. More Likely to work with a real NACA
duct. Not guaranteed however.

You are right about the double pass and I am converting my Howe Chevy
rad to two pass as we speak.

Paul Lamar

Ken Powell wrote:

Jerry,
Just an idea for the cooling fan.  Rather than mounting the fan to the back side of the radiator, give this idea a thought.  Mount the fan on the floor of the exit duct and use a flapper door to control the exit airflow.  During ground operations turn the fan 'on' and use the flapper door to direct air thru the fan and out an alternate exit while at the same time the flapper door closes off the primary exhaust air exit.  Works just like  a heat box for cabin heat.  This could be made to work if you have a large area for the exit duct (BD-4???).

Ken Powell
kenpowell@aristotle.net-- 

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