A STAGNATION PRESSURE PROBE FOR SUPERSONIC AND SUBSONIC FLOWS.

This paper describes a probe which has been developed specifically to measure accurately the stagnation pressure of a supersonic gas stream. Measurements of the performance of the probe to date show that it is capable of measuring absolute stagnation pressure with an accuray of 0. 1 per cent in the Mach number range 1. 5 to 2. 1. No measurements have yet been made in the transonic range, but at low subsonic speeds the probe has demonstrated its ability to measure dynamic pressure within an accuracy of 0. 1 percent at a Mach number of approximately 0. 13. The permissible range of misalignment in pitch and yaw before the pressure recovery begins to deteriorate are functions of free-stream Mach number and are usefully wide.