fluiddy1.gif

I would like to comment on this figure lest someone gets
the idea the duct shape shown on the lower half of the 
figure is ideal. Unfortunately it is not. The top,
most important part  of the drawing is absolutely correct. 

After World War II improvements were discovered
in duct shapes for cooling radiators. Much of what Hoerner wrote
about was based on prewar and war work in Germany. A more modern
duct would be bell shaped with the rad located at the large
end of the duct. 

A drawing of such a duct can be found on the ACRE NL web site 
http://home.earthlink.net/~rotaryeng/  titled; "Excellent duct design
from "Aerodynamics of Propulsion Kuchemann & Weber book chapter 12." 

Paul Lamar
 
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