A cryogenic impact probe for hypersonic low-density flows

Description of a cryogenic probe used for the measurement of momentum flow rates in a hypersonic low-density flow. The cryoprobe is a truncated copper cone of circular cross section with a copper slug heat sink positioned directly behind it to delay heat transfer from the balance to the probe. The probe is cooled by a 20 K helium jet. The procedure used in obtaining a momentum flow rate measurement is described, and the results of a number of such measurements made with the proposed arrangement are presented.