Validation Of The Rotorcraft Flight Simulation Program C81 Using Operational Loads Survey Flight Test Data PDF Download

The Rotorcraft Flight Simulation Program C81 (Version AGAJ74) was run, simulating a wide variety of flight conditions, in order to gather data for comparison to flight test data and data originating from other analyses, to determine the accuracy with which the C81 program predicts various characteristics of articulated rotor helicopters. The C81 input data were prepared, modeling the H-53 and S-67 helicopters, and runs were made to obtain trim, performance, stability, time history response, and rotor loads data predictions. The results of this study of the application of C81 to articulated rotor helicopters pointed out severe limitations to its application to rotors with any significant blade parameter discontinuities. Even under most favorable circumstances, this study did not indicate any significant increase in accuracy over other methods available for handling the disciplines covered by C81. While the ability to treat performance, stability and control, and rotor loads all within the same program has some advantages, in this case the advantages appear to be offset by excessive running times required for performance and maneuver response problems which normally can be handled by much simplier and quicker running programs. (Author).