http://upload.wikimedia.org/wikipedia/commons/6/61/Kort_nozzle_cut_view_top1.PNG
i've read a lot recently about shrouds around fans, this is maybe the best set up.... it's the Kort nozzle, for this to work the clearence between the fan and the nozzle has to be quite tight, this increases the thrust ..
i'm not sure if it works for air, i expect so... because my tugboats were damed draughty on the workbench and by God it's powerful
only drawback i can think is that it's very directional, the exit air doesn't fan out, it exits parallel.
i've read a lot recently about shrouds around fans, this is maybe the best set up.... it's the Kort nozzle, for this to work the clearence between the fan and the nozzle has to be quite tight, this increases the thrust ..
i'm not sure if it works for air, i expect so... because my tugboats were damed draughty on the workbench and by God it's powerful
only drawback i can think is that it's very directional, the exit air doesn't fan out, it exits parallel.