> > > >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

Hi Tracy:

        D'oh! Just like the hydraulic fluid heat exchangers in the fuel tanks
of turbine airplanes. I used to work around them on Gulfstreams... Of course,
you have aluminum skins while the Cozy's are composite.

Regards,
James

 
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