REFLECTOR: Tim England Chevy V6/Water Cooling Video

[Al Gietzen]

Chris-

For your hot-running rotary, you had better at least plan to use ram air-
might get by with the NACA's for oil coolers though.........

Alex

Or; the other way around; depending on the pressure drops across the cores.
Most typically it is higher for oil coolers.   The only thing "hotter" about
a rotary is the EGT (well other than HP/lb, small size, etc :).  The amount
of heat rejected for a given HP is essentially the same as for an aircraft
engine.  The other difference with a rotary is that a higher fraction (about
1/3) of the reject heat goes to the oil.

Near the back end off an airplane, the rule of thumb for heat exchangers is
ram scoop.

Al