Full-Scale Wind Tunnel Test of the UH-60A Airloads Rotor

A full-scale wind tunnel test of the UH-60A airloads rotor was recently completed in the National Full-Scale Aerodynamics Complex 40- by 80-Foot Wind Tunnel. The rotor was the same one tested during the landmark 1993 NASA/Army UH-60A Airloads flight test and included a highly pressure-instrumented blade to measure rotor airloads. This paper provides an overview of the wind tunnel test, including detailed descriptions of the hardware, instrumentation, and data acquisition and reduction systems. In addition, the data validation process, the test objectives and approach, and some sample results are presented. The test has produced unique data not available from the flight test, including data from new measurements as well as data acquired at conditions outside the conventional flight envelope. The new measurements included rotor balance forces and moments, oscillatory hub loads, blade displacements and deformations, and rotor wake measurements using largefield Particle Image Velocimetry and Retro-reflective Background Oriented Schlieren. The new flight conditions included 1- g flight simulations up to advance ratios of 0.40, parametric sweeps at non-standard conditions, including multiple sweeps into stall, and slowed rotor simulations up to advance ratios of 1.0. These new data should provide an excellent resource for validating new and emerging predictive tools. Presented at the American Helicopter Society Annual Forum (67th) held in Virginia Beach, VA on 3-5 May 2011. Supported in part by NASA and the U.S. Air Force.