A cooling fan comprising a housing that connects to a chassis that is
operable to support an electronic component. An axial duct runs through
the housing. A blade assembly is rotatably disposed within the duct and
comprises a plurality of fan blades that extend radially from a hub to a
fan diameter. The axial duct has a chord length at least equal to the fan
diameter. A motor assembly is disposed within the axial duct and coupled
to said blade assembly. The cooling fan provides a cooling capacity of at
least 1.5 air horsepower per cubic inch volume of the cooling fan.