On Thu, 17 Jul 2008 05:42:40 -0700 (PDT), rashid111
wrote:

The problem is they already have an impeller fan on the shaft that
"tries" to drive the air out of the bottom exhaust. Now that one is so
inefficient of design that I can barely feel the air moving even at
the top RPMs .

Sounds like a ideal application for the 120V. muffin fans I salvaged
from outmoded Dot Matrix printer soundproofing enclosures.
Gerry :-)}
London, Canada