I still consider Kuchemann & Webers's book the Aerodynamics
of Propulsion to be the last word on ducted fans but
Martin Hollmann's book on Modern Propeller and Duct
Design is not bad. I got my copy at Spruce and Speciality
but I think Martin advertizes in the back of EAA's Sport Aviation 
mag.

Here is a pertinent excerpt from page 98 and 99.

holmduct.jpg 

Paul Lamar
 
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