A short static probe with good incidence characteristics at supersonic speed

Abstract

Tests carried out on a short static probe at supersonic speeds between Mach numbers of 1.1 and 2.5 are described. The probe consists of a 50° included angle cone-cylinder having sensing holes 0.98 calibres aft of the cone-cylinder junction. The tests show that at zero incidence the probe measures a pressure (approximately independent of Mach number) of 0.793 times the local static pressure. They also show that, at up to l8° incidence in any pitch plane, the pressure measured is 0.763 ±0.33 times the local static pressure. For a limited Mach number range near a Mach number of 1.6, this accuracy can be maintained to incidences over 30°. Of particular interest is the fact that relatively small internal differences between externally identical probes appear to have a significant effect on the incidence characteristics and in some respects can improve the performance.