A COMPREHENSIVE HOVER TEST OF THE AIRLOADS AND AIRFLOW OF AN EXTENSIVELY INSTRUMENTED MODEL HELICOPTER ROTOR

A model test was conducted to study the aerodynamics of a modern helicopter main rotor in hover. Comprehensive data were obtained for a 9.4 ft. diameter, Mach-scaled model of a UH-60A (Black Hawk) rotor, including: rotor performance (from a balance), blade surface pressures (from 176 miniature pressure transducers), flow field velocities (from laser velocimetry), aeroelastic deflections (from blade strain gages), wake geometry (from smoke and shadowgraph visualization), and blade boundary layer condition (from surface hot films). New experimental techniques were demonstrated during this experimental program. The model was tested using two interchangeable tips: a swept tip that corresponds to the basic UH-60A rotor, and a 3:1 tapered tip. This paper describes the experiment, presents a selection of the results, and summarizes the conclusions that have been drawn regarding the aerodynamics of the model UH-60A rotor in hover, and the effect of the 3:1 tapered tip. The paper further serves to introduce the data base, which is being made available for validation of analytical and numerical techniques.