X-Mozilla-Keys:                                                                                 
RJohn15183@aol.com wrote:

In a message dated 8/12/99 5:32:06 PM Central Daylight Time,
rotaryeng@earthlink.net writes:

I think I have finally figured out how to get enough radiator
 area useing only one rad to cool 250 HP or so.

The intercooler is a nice setup but IMHO I don't think the coolant radiator
will work Paul. The intake is to close to the prop. All the successful WWII
liquid cooled planes had one thing in common. Rad intakes set way back from
the prop to get "clean" airflow.

P-40 and Stuka's are perfect examples. They kept making those scoops under
the nose bigger and bigger trying to get them to cool. Boy, did they turn out
to be big ugly, draggy scoops that STILL did not cool adequately in climb.

In the case of the P-40, the engineers wanted wing rads ala spitfire to get
"clean" airflow outside the prop arc (plus the high pressure air under the
wing) but the Army brass wanted the rads up front. They thought it made for a
cleaner installation.

Look at the difference in size between the p-51 or Spitfire inlets and the
p-40/Stuka inlets. It's all because of the disrupted flow aft of the prop and
the thrust reversals as the prop blade goes by. Plus, the thrust reversals
caused fatigue in the fins leading to leaks.

Rob

Yes I am a little worried about this. There are some airplanes around
however that seem to be working with this set up. I wonder if
those WW II airplanes had thin rads with proper diffusers.
Most attempted to force the air through thick vertical radiators.
The trick (I think) is too slow the air and make it turn 90 degrees 
and go through a rather large area yet very thin rad.

Paul Lamar
 
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