What if(with all that has been, said, done, and tested) one could find a smalled fan assembly?
Wouldn't that in itself produce less Mass of air? Then again, the shroud and housing would have to be modified for the smaller unit...But, could it be done? I've seen Jetski turbine propelors that look very similar to a 911 5 finned fan ( 9 fins if I'm not mistaken) and about 1/4 to 1/3 smaller in size as well...
Just adding to the fire
Regards,
Ephry