Sub-Miniature Pressure Sensor Installation for UH-60A Main Rotor Blade Air Loads Flight Test Program

Abstract

A UH-60A (Black Hawk) full-scale main rotor blade has been instrumented with 242 subminiature pressure transducers placed beneath the blade skin. The instrumented blade will be flight tested on a UH-60A helicopter at the AMES Research Center. The pressure transducers are of the sub-miniature silicon full-bridge type with a small diameter tube (.028 inches OD) leading into the pressure sensing cavity. Fifty of the transducers have built-in temperature monitoring sensors used in correcting the pressure data. The pressure signals and corresponding temperature signals will be processed by PCM Encoders and FM mulitplex systems. This paper describes the following: the pre-selection testing of the pressure transducers which included sensitivity, centrifugal effects, fatigue testing, etc.; the mechanical method of installing the transducers as well as the wiring installation beneath the main rotor blade skin surface and the final/periodic calibration of the installed transducers by using a "Vacuum bag" which encompasses the entire main rotor blade.