UH-60A airloads data acquisition and processing system

National Aeronautics and Space Administration, Ames Research Center, recently completed the joint NASA/Army UH-60A Airloads Program. The objective of this program was to make in-flight the measurements of rotor blade airloads, blade vortex interaction, and blade acoustics. An advanced digital instrumentation system, capable of synchronous acquisition of several hundred high frequency pressure channels was designed and developed to gather the required airloads data. The instrumentation system was designed to operate on the rotor hub of a Blackhawk helicopter acquiring data, in night, from pressure transducers, strain gauges, and accelerometers embedded in the rotor blade, built under contract by Sikorsky Aircraft. A parallel effort was initiated to develop a ground telemetry system with the capability to handle the 7.5 megabits per second PCM-encoded telemetry data, generated by the instrumentation system, in real-time. The purpose of this paper is to describe the design and performance of the rotary data acquisition system which was used to digitally acquire high speed rotor blade pressure data. These data were found to achieve the flight test research objectives of the UH-60A Airloads Program