a temperature probe has an elongated spindle - like body with an axial bore of uniform diameter extending entirely therethrough . the forward end of the probe has a knife - sharp edge surrounding the bore opening for ice - free performance . an annular air intake in the bore wall leads to an annular , rearwardly and radially outwardly extending sensor channel containing a bare wire element in an annular zig - zag pattern relative to air flow in the channel . the channel has an outlet near the radially widest part of the probe body , allowing venturi action of the exterior air stream to aid in drawing air through the channel from the bore . a heating element may be mounted downwind of the sensor element . the channel and sensor element are radiation shielded by a hollow area in the probe body between cooperating walls , and bleed holes may direct boundry layer air into the hollow area upwind of the sensor element and out of the hollow area downwind of the sensor element .