Investigation of UH-60A Rotor Performance and Loads at High Advance Ratios.

Wind tunnel measurements of the performance, airloads, and structural loads of a full-scale UH-60A Black Hawk main rotor operating at high advance ratios (up to 1.0) are compared with calculations obtained using the comprehensive rotorcraft analysis Comprehensive Analytical Model of Rotorcraft Aerodynamics and Dynamics II to understand physics and quantify this comprehensive code's accuracy and reliability in the prediction of rotor performance and loads at high-advance ratios. Detailed comparisons are made on rotor thrust, control angles, power, and section loads to illustrate and understand unique aeromechanics phenomena in this regime. The analysis correctly predicts the thrust reversal with collective at high advance ratios. Rotor induced plus profile power is also reasonably well predicted with proper modeling of the shank. Airloads and structural loads correlation is fair. A significant underprediction of 2-per-revolution structural loads is observed. [ABSTRACT FROM AUTHOR]