Application of Rotorcraft Flight Simulation Program (C81) to Predict Rotor Performance and Bending Moments for a Model Four-Bladed Articulated Rotor System

Abstract : Four sets of model H-34 helicopter rotor blades were built and tested by the Sikorsky Aircraft Corporation. Rotorcraft Flight Simulation Program with Aeroelastic Rotor Representation, Program C81, was used to predict rotor performance and blade bending moments for comparison with the test results. Performance predictions made using the steady-state two-dimensional airfoil data (GFE) supplied by the Army for the model airfoils showed stall characteristics at much lower rotor lift levels than recorded in the tunnel test. Application of unsteady aerodynamic and yawed flow effects did not sufficiently improve the performance correlation. The lift and stall characteristics of the model rotor in the tunnel were found to be very similar to full-scale 0012 airfoil properties.