Wherever the probe is located compressibility will affect the temperature
at our operational speeds. If the probe is attached to an intelligent
device that also knows the airspeed and altitude, then the True Air
Temperature along with the True Airspeed can be computed
and presented. This is true of the Rocky Mountain Instruments
micro-encoder and probably the fancy glass panels. We are past the Cessna
"stick your pinky in the wind" era.
A venturi can affect a temperature probe in the following ways. If
the probe is located where incoming air is compressed, such compression can
cause a rise in the temperature and if it is in an area where the air is
expanding, there is a cooling effect. Gas laws explain this fact.
BTW, I have a secondary OAT probe (VM EPI 800 system) located in an
insulated place thru the fuselage fillet where it
protrudes into an area forward of the flap hinge.
Scott Krueger
AKA Grayhawk
Lancair N92EX IO320 SB 89/96
Aurora, IL
(KARR)