Methodology Correlation for Coaxial Rotor and Blade Load Prediction

This paper focuses on rotor blade loads analysis and correlation for coaxial rotor applications. Predicted rotor blade loads from two methodologies used in-house at Sikorsky Aircraft were compared with flight test data from a coaxial rotorcraft. The flight conditions for the correlation range from low speed transition flight to high speed cruise flight and a pull-up maneuver. The methodologies being correlated include both a high-fidelity CFD/CSD (Computational Fluid Dynamics coupled with Computational Structural Dynamics) methodology and the Sikorsky-proprietary flight dynamics simulation tool, GENHEL. Detailed blade load correlations were presented at multiple representative flight conditions. In addition, a survey of the prediction accuracies from these tools were carried out to quantify the overall prediction accuracy using critical metrics for both blade structure load sizing and rotor vibrations to support practical design application.