"DoN. Nichols" wrote in message
...
.. :-)

As for how they work -- for *good* ones it is the same principle
as the airfoil of an aircraft wing. For cheap fans, it is an
approximation of the proper shape with just bent metal, so it is not
particularly good -- but it costs little to make -- just stamped out,
instead of careful contouring to a specific design as a real aircraft
propeller would have.


Never forget that a simple 'propellor' is nothing more than a simple
screw.........where things begin to get more complicated is when you start
into dealing with compressable fluids...eg..a boat propeller instead of a
fan blade.

--

SVL