Cooling a liquid cooled engine is fundamentally
and intrinsically much different than cooling an air cooled
engine. Close does not count with liquid cooled engines. 
Pregnant or not pregnant, dead or not dead, swimming or sinking. It 
is a black and white situation. Low cooling drag initially is
way down on your list of priorities.

If the temperature of the bulk coolant goes beyond the boiling temperature
overall boiling occurs.  All hell breaks loose and the coolant is
forced out of the water jacket through the pressure cap overflow valve by
massive amounts of hot vapor or steam. Once boiling of the coolant starts it
is all over in an instant. Less coolant, hotter metal, more steam, less
cooling. One might say the cooling system pops like a pop corn. Thus the
cooling system becomes extremely unstable. Its like critical mass in
a nuclear explosion. This is THE major difference between the air cooled 
engine and the liquid cooled engine. Needless to say this cannot be 
allowed to happen in an aircraft engine.

A few bad experiences like this during climb out can be very discouraging
indeed. 

Don't take half measures. Don't experiment with ducts, rads or scoops that
might or might not work. Use the best plumbing available. Learn from history. 
Look at all the engineering  work that has been done in the past 100 years 
and copy the best. If something looks marginal go for the larger size, 
the bigger hammer, the best possible solution.

Later, when you have flown for awhile under all weather conditions you can think
about reducing the cooling drag or improving the cosmetics.
 
Paul Lamar
 
The AirCraft Rotary Engine NewsLetter.              Powered by Linux.
ACRE NL web site.
http://home.earthlink.net/~rotaryeng/            http://www.linux.org