Anderson Ed wrote:

Fascinated by the depth and extend of discussion on radiators and
cooling issues.  If I have followed the track on "thin" vs "thick" the
consensus (but not unanimity) of opinions seems to favor the thin due to
drag and delta T efficiency factors.

 Now because the acknowledge physical space constraints in most airframe
applications, the thought appears to be to stack a couple of smaller
"thins" together which (as mentioned by another) begins to appear very
suspiciously like a "thick".  I agree that mainly because of the
flexibility in connecting coolant flow to several "thins", greater
efficiency is possible due to better control of delta T distribution.
So that may make it possible to have an overall smaller depth with
several "thins" (not as thick) than one "thick."  However, I seriously
wonder whether the weight, bracing, plumbing, number of
connections,cost, etc.,of stacking "thins" do not begin to offset the
possible benefits. My impression is that "thins" may be better for
slower airframes which may not have the airflow Q to needed for "thick"
radiators, but that perhaps for the higher Q applications that advantage
diminishes. My 0.02 worth

Ed Anderson

That is a very good summary of the situation Ed. I might add
that for a given volume of radiator both drag and cooling
efficiency get better the thinner it is. I think two thins are
not that much trouble plumbing wise. Sure beats two thicks drag
and cooling wise. Say, Jim Mosur's configuration verse's Tracy's
configuration.
 
Now if you are welding the end tanks four thins back to back or
zig zag may be more expensive but I don't think they will be any
less reliable than one thick. If you use common modern junk yard
thins then they will be cheaper than a custom thick. You will
have a heck of a time finding an aluminum thick in a junk yard
anyway. You might get good prices at a rad shop for new thin cores
without header tanks.

As far as weight goes they have the advantage as there is less
water in the less volume more efficient rads.

Slow airplanes usually have a lot of aft fuselage volume to work
with so just about anything half way well designed will work
well.

Paul Lamar
 
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