Instrumentation of GALCIT Hypersonic Wind Tunnels

For the purpose of developing more efficient rockets and missiles for long ranges, it is necessary to acquire basic information 1n the hypersonic Mach number range of 5 to 20. To obtain such aerodynamic information two Hypersonic Wind Tunnels, Legs No. 1 and No. 2, have been \ndeveloped at GALCIT. With Leg No. 2 it is possible to obtain aerodynamic information in one-phase air flow at a Mach number of about 11. \n \nDuring the early operation of the Leg No. 1 tunnel at a Mach \nnumber range of 2 to 7 it was necessary to develop various new experimental techniques to obtain reliable aerodynamic information. The static pressures in the test section varied in the hypersonic Mach number range from about 2 to 1/4 millimeters of mercury while the static temperature was of the on the order of room temperature to 1100°F. A great \ndeal or time was spent in developing manometer boards and special valves and in perfecting new techniques for measuring these low pressures very accurately. The initial operation phase or the Leg No. 1 tunnel was \nspent in developing adequate hypersonic instrumentation for static pressure, total head, heating facilities, and a stagnation temperature controller. \n \nIn this report. the important instrumentation developed over the past few years will be discussed in detail. The information should be useful for other groups planning basic research at hypersonic Mach numbers.