[TR] Push or pull

[Jim Muller]

On 23 Oct 2007 at 19:58, John Macartney wrote:

> I take the view that the standard fan was only reasonably good at
> engine speeds up to about 2000rpm. After that it became more of a
> 'drag' and just absorbs useful power I'd prefer goes to the wheels.

If the fan can really affect the car's performance then this is quite 
simple.  The fan has to be near the radiator, which is always up 
front, isn't it?  At least in our cars it is.  And if the fan is 
pushing from the front then it must be trying to make the car go 
backwards.  You can't push something forwards from the front.  But if 
it's pulling from the front then it must be trying to pull the car 
forwards, which is exactly what you want it to do.  So it's obvious, 
for best performance the fan must be pulling the car forward.  And 
the faster the car goes the more wind hits the radiator, which gives 
you more cooling.  So you win both ways, better performance plus more 
cooling if it's pulling instead of pushing.

I really don't see what the big issue is here.

(If your fan is pushing, just turn it around on its shaft.  The 
blades will then be angled the opposite way.  Yeesh, do I have to 
tell you people everything???)

-- 
Jim Muller
jimmuller at rcn.com
'80 Spitfire, '70 GT6+



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