Another interesting tid bit was the the fact that the S.6B's RR engine
was rejecting 40,000 BTU each minute by the surface radiators
covering almost every square inch of surface on wings and floats.
40,000 BTU's/min  is 703,333 Watts! Or 1,280 HP worth of waste
heat. In the earlier, S.4 design, the conventional cooling radiators
mounted in the wings were responsible for 38% of the total drag.

Hi all:

        I thought about a surface radiator for the Cozy oil cooler
but haven't pursued it very hard because of:

        1) Maintenance - Porsche tried it in the 50s-60s on their racing

cars

        and gave up due to leaks.

        2) Weight - The surface would need to be alumimum plus the

piping,

        etc. I thought about using that carbon conductive foam but

corrosion...

        3) Temp - I'd have to insulate the cooling surface from

surrounding

        structure - not a biggie, but still weight.

        Of course, NO drag is the driver here! If someone has

better/different

ideas/fixes for these problems, please let me know.

Regards,
James

Correct, the problem with this idea is the weight, complexity and high
chance of leaks. The 'fix' I tried (and plan to try again) was to use the
wet wing fuel tanks as radiators (almost zero weight gain ).  This of course
requires that the fuel itself be used as the heat transfer medium.  I plan
to use this or a total loss distilled water evaporative system (spray on the
oil & water heat exchangers) on my 20B RV-8.  Only time it is needed is
during climbout so I believe it is imminently practical.  This way the basic
cooling system can be designed for minimum drag at cruise.  The -8 is NOT
going to be a 'dirty bird' like my -4 :-)

Tracy Crook
tcrook@rotaryaviation.com
www.rotaryaviation.com

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