<VV> Electric cooling fan results

[Roger Gault]

Now, Ned, you know me better than that.

Of course it's flow that matters.  (Actually, mass flow, not CFM - and
Reynolds Number).
Unless you have a much stronger wisher than I have, it takes pressure to
make air flow through the tiny openings in the Corvair head.  My choice of
the word "pressure" was intended to emphasize the fact that we're in the
realm of pressure blowers here, not volume blowers.  We have just seen the
results of a test of a design by a fellow that thinks CFM is all there is to
the problem.

I have serious doubts that the 911 fan, being single stage with no fixed
blades to help recover some pressure, can put out enough pressure to force
enough air through the heads to cool the Corvair unless it's run at such a
high rpm that we're back in the high hp problems we think we have now.  My
searching for a commercially available axial fan with published
specifications that indicate it might be suitable have been fruitless.  The
only alternative fans I've seen that might work are centrifugal blower
impellers that look remarkably like the LM fan - except the look like they'd
have a higher moment of inertia.

Roger

----- Original Message ----- 
From: <AeroNed at aol.com>
To: <virtualvairs at corvair.org>
Sent: Monday, July 30, 2007 12:35 AM
Subject: Re: <VV> Electric cooling fan results


>
> In a message dated 7/29/2007 10:59:25 P.M. Central Daylight Time,
> r.gault at sbcglobal.net writes:
>
> Does the  911 fan even put out enough pressure to cool
> the  Corvair?
>
>
>
> Argh!!!! Pressure is NOT what does the cooling, it is air flow. Think of
it
> this way...If the shrouds were totally sealed so no air could get out the
fan,
>  any fan would pressurize this vessel. That pressurized air would do
> absolutely  nothing to cool whatever is in it. The pressure is what
enables the air to
> flow  though. It is more difficult to measure airflow directly. You can,
> rather  easily, measure the pressure between two locations (or relative to
another
>  position) to calculate the air flow. Also fans are typically rated in
> pressure  capability and air flow as a measure of the fan's efficiency (ie
when it
> starts  churning the air rather than moving it).
>
> Ned
>
>
>
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