"Marc Ramsey" wrote in message
news
I'm only engaging in standard usenet-style uninformed speculation, but I'm
guessing that the flow around the nose is altered such that the pressure
differential would no longer be consistent with the angle of attack.
Also, if putting two ports on the nose was adequate, why did DG go to the
trouble of putting 4 ports above the wings?

Marc

Like you, I'm only guesssing but it might be the DG system was intended to
be a stall warner rather than an AOA indicator although I grant the
difference is small. Ports on top of the wing might sense the progression
of flow separation at the root as a stall begins.

There's a probe call the "BAT" which presets a hemesphere with a ring of
pressure ports to the airflow. A computer collects the pressure data from
each port and outputs the Alpha/Beta angles as well as turbulence data.
See: http://www.atdd.noaa.gov/Research_Pa...WEB/batweb.htm