Mark Wrathall wrote
Is is realistic to expect to reject the waste heat load of a 200 hp rotary
through air cooling? The engine is so compact where would you add the
required finning?

That is a very good point.

Paul Lamar

Moller tried in the late 80's to make a two rotor air cooled.  It failed
because the "back" rotor overheated.  It might be possible to design a
complex fin system (they were working on one) or go more circumferential
but it is not as easy as "air cooled submarines"  Such is the case with any
high specific output engine.  BTW, how do you air cool the center housing?

Jeff Spitzer

Might not work, but if you can design an aircooled rotary it would be
likely to have fewer parts (water pump, radiator,hoses, hose clamps, etc) &
lower weight than a water cooled design.  OTOH, water cooling is often
simpler to design and can likely be made more compact.  The center
housing certainly would be a challenge, but the highest specific output
street  car engine EVER until the new Honda sports car was the 1969 Porsche
911S with a *real* 200 hp from 2 liters and it could cruise at top speed
on the autobahn all day.  High specific output aircooled motors are more
difficult than low, but not inherently impossible.

I was looking at the ideal case, assuming unlimited resources, etc.
As I said - We'll have to make do with what we have, that is reality,
as of now the high output aircooled rotary is a fantasy.  An attractive
one, at least to me.  Can't have a loss of coolant accident, almost
certainly lighter and simpler, likely to be even more reliable as systems
not installed never will fail.  Would seem a bit easier than the 911S
due to the lack of an ultra-hot exhaust valve that needs cooling in
a VERY crowded cylinder head.  Dreaming.   On with the real world
reengineering of what we DO have, a water cooled rotary.

Bill

 
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