<VV> Re: [fastvair] Fans

[ScottyGrover at aol.com]

In a message dated 8/5/2007 7:56:19 P.M. Pacific Daylight Time,  
eschakel at earthlink.net writes:

 
 
 
Scotty, before you go into the world of fan design and manufacture,  does
anyone on this list have contemporary fan test information?

All  of the fan data I've seen comes from ancient SAE or GM tests using  OE
configurations on stock engines. The highest RPM listed in Bob  Helt's
Classic Corvair is 5200. Does anyone on this list have real fan HP  losses at
the elevated RPM the FastVair folks tend to push? I run my engine  to 7200
now and then, and there are rumors of some of the eastern Vairs  pushing over
8000 regularly. My cut-down LM magnesium fan has been more  than adequate in
street driving, and no problem on the track in 110 degree  conditions since I
added a front-mount oil cooler. 

The estimates  I've read for losses at 6500 with a cut-down fan range from 9
HP to 23 HP,  which is probably interpolated from GM data or just  flat
made-up.

So, what's a new fan design worth? If I'm losing 9 HP  at high revs, I don't
think there's any good reason to screw around with  fans, particularly if the
whole drive and ducting system has to be changed  to accommodate the new
design. Now, if I'm losing 23 HP at high revs, let's  talk about a new fan
design. We know the electric fan isn't going to get  the job done under a
load as initially offered, and that is a great step.  

Other than that, however, we seem to be heading for the stratosphere  again.
Anybody have data?

Eric Schakel

_____  






All I can advise is--get on the 'Net, search for "Fan Laws"--that should  
give you a clearer picture of what a fan acts like with elevated RPM--the HP to  
drive a fan varies as the CUBE of the RPM--I'm not sure whether a fan belt  
wouldn't have lots of slippage when the load gets that high.
 
Scotty from Hollyweird



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