Dick,  While my installation is in a Tractor aircraft,  I have
installed fans on the  fuselage mounted radiator.  I am not the least
concerned that a free wheeling fan may eventually have bearing
problems.  If it does, I will replace it.  I have an  electric fan on
my RX-7 that has been free wheeling for more than 100,000 miles and
is still in good shape.     I don't know what your schedule is, but I
should be running this engine early next  year and   should be able
to come up with real data about what it takes to cool a 13-B on the
ground.  I think that  the fan will prove to be entirely adequate for
all ground ops.   This should allow for a  SMALLER inlet scoop.  I am
going to size mine   to become  fully effective in an airstream of
125 m.p.h. plus.  The advantage of the fan is that the engine will
not be overheating prior to starting the take-off roll.  By the end
of the runway, I will be going fast enough to no longer need the fan.
BTW,  the manufacturer of my fan, Flex-a-lite, claims that the fan
does not impede airflow through the rad when the fan is free
wheeling.   I don't know if you can believe them or not.     Jerry

Jerry,

  I think you got that wrong on the inlet. By putting a windmilling fan in
the duct you've created a flow restriction. I think with the fan installed
you'll need a BIGGER scoop, not a smaller one. Grab that fan and stick it
out your car window while you're zooming down the road at 125MPH and try to
hang onto it and I think you'll see what I mean.

Mike Wills

I don't think it will see that speed in the duct.

Paul Lamar
 
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