<VV> fanz - SPAL #30102113

[AeroNed at aol.com]

In a message dated 8/3/2005 11:56:05 P.M. Eastern Standard Time,   
r.gault at sbcglobal.net writes:


AERONED!  WHERE  ARE YOU?


Trying to stay out of the fan fray....
 
Calculating Reynolds' number will not really help. It's primary use is for  
scaling drag effects, like going from a scale model (wind tunnel) to a full 
size  airplane. It might be used to determine the optimal length of the cooling  
fins.
 
The most important thing the fan does and what keeps the engine cool in  
movement of the air. The pressure it builds in the top shroud is a by product of  
moving the air. If the engine was not there, there would be very little  
pressure, yet the air would still move. The pressure that builds up in the top  
shroud is just another challenge for the fan to work against. If the pressure  
gets too high, then the fan won't push any air.
 
The engine heat is "carried off" by the moving air. To measure the  
effectiveness of any potential fan replacement you measure the speed of the air  at the 
fan output in pounds per minute or cubic feet per second (these are both  
related through the characteristics of the air, density, temperature, humidity,  
ect.)
 
So the bottom line is air speed is good and getting it go where it needs to  
go.
 
Floating back to my cloud,
Ned