<VV> Fans/.my take

[JVHRoberts at aol.com]

A Corvair fan, however you want to call it, is VERY inefficient. And it  only 
makes about 10" of water column, or less than 1/2 PSI. Call it what you  
will, it does a TERRIBLE job of converting HP into flow. It converts most of the  
power it consumes into heat.
 
The cylinders are primarily air cooled. 
 
Given that a Porsche fan moves a LOT more air, at a LOT higher pressure, on  
LESS HP, well, to me that looks like it's a LOT more efficient. 
 
The Corvair cooling system was designed for an 80 HP engine, and to be  
inexpensive. Not to cool 180 HP turbo motors! <G>
 
In a message dated 8/1/2007 11:38:48 P.M. Eastern Daylight Time,  
levair at aol.com writes:

Of  course the Corvair fan is inefficient for a fan.
It is not a fan; it's a  centrifugal (centripital?) blower.
It is akin to a Paxton of Vortech  supercharger or a turbocharger compressor.
The top shroud is the compressor  scroll. Just like a supercharger, the 
scroll needs to be a tight clearance to  the compressor blades. The Corvair scroll 
directs/flings the compressed air (2  to 6 psi) right out to the cylinder 
heads where the cooling occurs. The  cylinders are primarily oil cooled 
--preferably by a huge remote front mounted  cooler.
?? As a compressor, it is extremely efficient (much more than a  fan) in a 
sweet spot just like any other centrifugall compressor and  inefficent below 
that spot and goes into surge/cavitation above that spot .  The cut down racing 
fans are trying to avoid that cavitation.
?? Porsches  have?FANS? that are linerally inefficient. Corvair compressors 
are non  linerally efficient.
?? The pulley changes are to move that "sweet spot" to  the rpms being used 
i.e.; 4000 rpm for street sweet spot and change the pulley  ratios (slower) to 
move the efficient sweet spot to the racing 7000 racing  rpm.
?? Changing the straight blades to curved ones?improves the efficiency  and 
is available as a "hop up" for the Paxton blower.
?? The case cover/fan  mount is streamlined properly.

All and all a very good job by GM's  aerospace engineers.

Fire away,
Warren


 



************************************** Get a sneak peek of the all-new AOL at 
http://discover.aol.com/memed/aolcom30tour