Dynamic stall modelling of pitching moment and drag with a unified set of parameters

A semi-empirical dynamic stall model is presented for use in helicopter flight simulators and onboard flight computers. Dynamic stall remains a limiting flight condition for helicopters at high advance ratios and high-g maneuvers, and necessitates development of reduced-order models that compute loads in real time. As a continuation of the work in Ref [1], this work applies the Modarres semi-empirical stall model of Ref [2] to cases of unsteady free-stream velocity, and also contributes towards a goal of reduced-frequency-free parameters. Data correlated includes Boeing VR-7 water tunnel data in steady freestream and SSC-A09 airfoil wind tunnel data with steady and unsteady freestreams.