"Chris W" wrote in message
...
Corky Scott wrote:

Chris, what's a reverse NACA duct? My understanding is that they were
designed to work in one direction only, to bring in air with a minimum
of drag.

They don't work well, or at all, when placed on the fuselage or cowl
in a negative pressure area.

I had heard once that on some planes, a reverse or backwards NACA duct
would
be installed in the aft part of the cockpit to improve ventilation by
helping
suck air out of the plane. I also think I remember something about the
design being somewhat different.


--
Chris W

As I recall, it was shaped rather like a raindrop, but with about 1/3rd of
the surface raised above the craft. The pointy end was pointed into the
wind, with the outlet in the downwind, rounded side. The object was to
create a low pressure area, then use it to get the bad air out. If only I
could remember where I read about it!
--
Jim in NC