CORRELATION OF 2GCHAS ANALYSIS WITH EXPERIMENTAL-DATA

A broad engineering validation study of the structural and aerodynamic capabilities of the Second Generation Comprehensive Helicopter Analys is System (2GCHAS) has been conducted, 2GCHAS predictions for structur al deflections, aeroelastic stability, rotor performance, and blade ai rloads were compared with experimental data ranging from small-scale m odel data to full-scale wind tunnel and flight test data. Correlation with the Princeton beam test data confirmed that 2GCHAS gave satisfact ory results for moderate deformations of nonlinear structures, A small -scale torsionally soft hingeless rotor blade test model was correlate d with 2GCHAS aeroelastic stability results and confirmed the 2GCHAS c apability to predict aeromechanical stability of a hingeless rotor sys tem, For unsteady aerodynamics, 3-D wing dynamic stall wind tunnel dat a for an oscillating wing confirmed the 2GCHAS dynamic stall and unste ady wake modeling capability. Rotor performance predictions were corre lated with full-scale wind tunnel data for the S-76 rotor, Rotor blade loads and airloads predictions were evaluated using CH-47C model roto r blade data and UH-60 full-scale flight test data. Overall, the resul ts indicated generally satisfactory prediction capabilities for a wide range of rotorcraft problems using 2GCHAS.