A fast response probe system for in-flight measurements of atmospheric turbulence

A fast response probe system for in-flight, three-dimensional measurements of atmospheric turbulence is presented. The system comprises a commercial five-hole probe connected to miniature pressure transducers by extremely short pneumatic lines. This design yields high dynamic response with negligible pneumatic transmission errors at least up to 10 Hz. The transducers are installed into a temperature-conditioned shell to eliminate thermal zero and sensitivity shifts during flight. The system has been tested on the Falcon D-CMET research aircraft of the German Aerospace Center (Deutsches Zentrum für Luft- und Raumfahrt, DLR) in Oberpfaffenhofen at flight altitudes up to 37 000 ft (11 278 m) and Mach numbers up to 0.75. Spectral analyses of the air-data obtained by the system confirm the predictions concerning its high frequency response capabilities. Simultaneous measurements with conventional air sensing devices installed in the aircraft provide evidence regarding the operational reliability and the accuracy of the system.