Jerry Hey wrote:

  My  present radiator needs to be retired with out ever having had  a
drop of water pass through it.    I have changed the inlets and outlets
and added/ removed various  brackets so many times that it has become
down right ugly.  Welds on top of welds and so on.   I could replace
the tanks but it is  a Griffin and there is that epoxy to worry about
overheating.....Nope,  time for a fresh start.

  I would like to have my memory refreshed on Chuck Dunlop's and Ian
Beadle's radiator core sizes.  Whatever size Chuck's is, I think it
would clearly work regardless of the outside temp, if the exit air was
not obstructed by the engine.     I think  that a rad as small as 450
cu in (and maybe even smaller)  would be sufficient to cool a NA 13B
provided it is breathing efficiently.  But I am interested in any
opinions to the contrary.

  C & R has a version of the Scirocco Drag Race radiator  which has the
same foot print (13" x 22")  as the as the Griffin Scirocco I have now
but with a smaller core volume  because they use 1" tubes where Griffin
uses 1.250" tubes.  The difference is 585 cu in vs. 468 cu in.  I think
the thicker rad would be less efficient for two reasons:  one it would
be more restrictive to air flow and two, the back portion of the
radiator would see air already heated as it passes through the front
portion of the  radiator. This would just get worse  as cores get
thicker, I think.    The more core the better, one would suppose,
unless by its very  thickness it is preventing the solution to the
problem it is intended to solve.  On the other hand, no matter how
efficient a radiator is, it still needs a certain core size to handle
the load.  Wish I knew that magic number.

The best of all worlds is a small foot print, thin radiator, with
plenty of air entering through smooth bell shaped ducts that  exhales
beautifully through a set of adjustable louvers.  How "little" can we
get away with is the question as it is with all things aircraft.

   Jerry

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