<VV> Corvair Fan

[Kent Sullivan]

Hi,

The axial vertical fan project that Bob Coffin and I have been inching along
for several years took an important step today. This morning I dropped off
the prototype (aluminum) hub, fan blades, and an alignment jig to my
favorite welder.

I should have it back in a week or so then I will post a picture on my web
site. The plan is for Bob to test the fan on one of his cars and do some
airflow measurements. This fan uses the fiberglass housing he made several
years ago that several racers are using with the Austin fan.

The new fan was designed (using the formulas from the "Fan Handbook:
Selection, Application, and Design", available on Amazon.com and other
places) to provide adequate cooling for street use. If it operates as
expected, hopefully all that might be required is adding some ducting vanes
to the underside of the fiberglass housing.

If all goes well, we would like to make the production fans out of something
much lighter than aluminum; perhaps a modern plastic. (But it needs to be
one that doesn't react with battery acid fumes. We all know the story of the
prototype Delrin fan creating formaldehyde gas!) There will be a
price/performance decision to make.

By the way, most of the delay was waiting for a friend to install and
provide power to the four-axis CNC mill that he purchased for his home shop.
That took longer than expected but it was worth the wait because he does
great work. :-)

Stay tuned...

--Kent
-----Original Message-----
From: virtualvairs-bounces at corvair.org
[mailto:virtualvairs-bounces at corvair.org] On Behalf Of JVHRoberts at aol.com
Sent: Saturday, July 09, 2005 11:14 AM
To: dkdewald at pasty.net; virtualvairs at corvair.org
Subject: Re: <VV> Corvair Fan

 
I think one needs to look beyond Corvair cooling blowers, and look to other
air cooled engines that make more power, etc., and have fewer cooling
problems. 
Corvair fans are centrifugal blowers, as you point out. Nothing wrong with
that, but the Corvair blowers, ANY of them, don't represent the best of what
there is, not by a LONG shot. 
Nor are centrifugal blowers the best for this application. Deutz air cooled
diesels, Porsche 911s, etc., typically use axial blowers. These tend to to
be more efficient, and can operate more linearly over a wider range of
speeds.  
Meaning, they don't go ballistic on HP when driven to redline speeds. 
Hydraulic drives, etc., are interesting, but KISS is always better.  <G>
 
In a message dated 7/9/2005 1:41:06 PM Eastern Standard Time,
dkdewald at pasty.net writes:

Hello  folks,

Based on my limited understanding of fluid flow, it is clear to  me that a
standard automotive radiator fan operates somewhat differently  than the
Corvair "fan."  The Corvair unit is a centrifugal blower,  and has more in
common with the blower in, say, a forced warm air furnace  (which blows
through ductwork--like the Corvair engine).  It is no  surprise to me that
attempts to use electric radiator fans end in failure;  fans are not
blowers.

I think that significant improvements could be  made in the efficiency of
the Corvair blower, particularly the late  magnesium style.  In my mind the
ideal blower would be modeled after  the early steel curved fin impeller but
molded from fiber reinforced  plastic.  This would be the minimum starting
point for making an  electric motor powered Corvair cooling system.

Has anyone considered  using a hydraulic fan/blower drive as done on heavy
construction and  agricultural equipment?  Just a thought.

Dale Dewald
Hancock,  MI


 
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