<VV> Air vs Water HP

[Bill Elliott]

I've pretty much bought into this reasoning...until recently.

Rich and I assembled the bits to put together a vertical fan for my track car (using items similar to how other Corvair racers do it).

The fan that's most often used in this application is the 11-blade plastic Austin America fan.  Now this appears to me to be a pretty standard fan and not 
one particularly suited to building up a head pressure to push air through the engine. (And it's not even particularly powerful.... and is often replaced with a 
metal fan with fewer blades for "tropical" applications despite the greater noise.)

And beyond that,  in it's original Mini/America application (where it pushes air through a sideways radiator) it is very often replaced with a standard 1000-
1100cfm electric fan which is seen as a performance upgrade since it pulls less HP.

So my question is... what makes the vertical fan assembly as used by Corvair racers cool the engine when it uses a fan most often replaced with electric in 
its original application, yet the same electric fans can't directly replace the Corvair fan?

I'll admit I haven't sat down and thought this carefully through, but at first blush it doesn't make much sense. What am I missing?

Bill

>Here are some things Rad Davis had to say about the general topic:
>http://www.mindspring.com/~corvair/RadFAQ/ElectricFans.html


>>Well.....
>>
>>A Corvair fan, no doubt, uses more HP than a water pump, there can be no
>>doubt. Given that electric cooling fans can cool waterpumpers just fine, 
>>with
>>reasonable amounts of power, but NOT a Corvair engine, it's pretty clear 
>>that
>>the Corvair has the more HP intensive cooling solution.