"Jay" wrote in message om...

I'd put forth the idea that the worst
case environment for an aircraft is always better than the worst case
for an automobile. Does anyone disagree on this point?

Yeah, I do. Many cars typically don't operate at 80% of rated power for long
periods.

Therefor, a cooling surface directly exposed to the prop wash does not
have to be as large in area as that of the radiator orginally designed
for that automobile.

Cars have fans too.