I remember visiting a Velocity project a number of years ago that had a well-constructed NACA duct in an improper location and it simply didn't do the job.  Rather than close it off and relocate it the builder installed a row of vortex generators in front of the duct about as far away as the duct was wide and it then worked like a charm.  Perhaps not the most elegant solution but another case for more than one way to skin the proverbial cat.  FWIW.

   <Marv>


 "Thomas Jakits" <rotary.thjakits@gmail.com> wrote:

"""
just recently read about the Naca:

It can work VERY WELL, *IF*
a) You have the right location
...snip...
"""