> > > 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

Mike, my fan is a pull through  on the opposite side of the rad from
the inlet duct and rad plenum.
The intake scoop has a volume that is roughly 1/3 the volume of the
rad plenum so I think the air will not be moving that fast.    On the
exit side of the rad,  you have the entire interior volume of the
fuselage.     Air entering the scoop at 200 m.p.h. will slow to 66mph
at the rad face and then slow even more on the exit side.  While I am
not going to blame anyone else if this does not work,  credit for the
design of my cooling system goes to many members of this group
particularly Paul and Bill Freeman who probably don't even remember
the excellent engineering they freely provided while this design was
coming together.    --Jerry

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