Rotorcraft Aerodynamics Models for a Comprehensive Analysis

Recent developments of the aerodynamics models for the comprehensive analysis CAMRAD II are described, particularly the unsteady aerodynamic models and dynamic stall models, and the free wake geometry calculation. Three models for the unsteady aerodynamic loads in attached flow are implemented: from incompressible thin-airfoil theory, from ONERA EDLIN, and from Leishman-Beddoes. Five dynamic stall models are implemented: from Johnson, Boeing, Leishman-Beddoes, ONERA EDLIN, and ONERA BH. A key feature of the implementation of these models is revisions allowing the retention of airfoil tables for static loads in all cases. Results are presented for a two-dimensional airfoil, a three-dimensional wing, and rotors. Extensions of the CAMRAD II free wake method to include hover and ground effect are described, including hover performance correlation.