<VV> Air vs Water HP

[CorvairEd at aol.com]

In a message dated 7/8/05 2:07:16 PM Pacific Daylight Time, 
Corvair at fnader.com writes:
So my question is... what makes the vertical fan assembly as used by Corvair 
racers cool the engine when it uses a fan most often replaced with electric in 
its original application, yet the same electric fans can't directly replace 
the Corvair fan?

Bill,
I'm not sure of this but I think if you were to check the RPM of the two fan 
applications you'd find that the mechanically driven fan is running at a 
higher speed, when the engine is above normal cruse, than the electric one.  This 
of course would flow more air through the engine when it's needed most.  One of 
our club members, Orville Eliason, tried for several years to cool the 
Corvair engine with electric fans but was not successful.  He ended up with three 
fans located across the front the engine compartment of a 65 which were ducted 
to the top of the engine cooling inlet.  There was one fan under the top cover 
and one on top turning in opposite directions.  The opening in the top cover 
was enlarged several inches.  The fans were turned on by an adjustable 
thermostat mounted on top of the left head.  No sense running the fans when the engine 
was cold.  He found that the best he could accomplish was to be able to cruse 
at 55 with the outside air temp above 90.  As the air went higher he had to 
slow down to keep from overheating.  The system did work fine for short trips 
or in heavy traffic.  The system also worked fine for high cruse if the air 
temp was below 75.

Believe me, if Orville couldn't make it work, it probably can't be done.  He 
had to run a very heavy alternator to power all of those fans so it was not a 
HP gain.  His main objective was to eliminate the fan belt to get more 
reliability.  I don't know about you but I don't have any trouble with fan belts.  I 
get up around 30,000 miles on a belt but change them about every two years.  
That holds true for water pumpers too.

Ed Corson (CORSA member)
Inland Empire Corvair Club