Paul, this would have no use in a tractor but in a pusher it might do some good..
Put a can on the prop hub coming back a bit into the cowl, put impeller fins on it. Some ducting around the impeller takes care of the flow.
Why not resort to an active air system and create a bigger pressure differential?
...Chrissi

Also I might add any simple mechanically driven blower system is indiscriminate
in its use of HP. It uses too much HP at high speed where you don't
need the cooling. Cowl flaps on the other hand taylor the air flow
to the cooling requirements of the engine as a function of speed.

I cannot emphasize that enough. If you are not using cowl flaps
you are burning too much fuel at any given cruise speed.

Paul Lamar
 
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