Vance and Emily Jaqua wrote:

Paul -read your twin fan concept with interest.
 Thought you might like this curve of maximum thrust
from 500 hp for various flow "disk" diameters at
speeeds . This is no loss conversion into jet stream
 power (perfect "pump") real expectations about
75 % of this at low speed to 90's above 250 or so.
3 eff sq ft drag area should be possible with clean
structure and good retracts - Vance

Thanks for sending that chart Vance. It looks very reasonably
to me. Would you be able to calculate what we would get out
of a 36 inch diameter fan with an 18 inch diameter hub... fixed
pitch fan?

36 inch gives me about 700 MPH tip speed at 6500 RPM if my calc's
are right. Dia X RPM / 60 = FPS
MPH = FPS X 0.682

Perhaps with a better blade we could go up to 38 or 39 inches.
I will revise my twin fan simulation accordingly.

Paul Lamar
 
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