An Innovative Lifting-Line Model For Proprotors In Axial Flight

Abstract

A time-stepping, lifting-line solution algorithm, designed to predict the unsteady aerodynamics of rotorcraft blades, is presented. This method extends recently developed lifting-line techniques -originally applied to prescribed-wake and free-wake wing problems- to the realm of rotary-wing applications. The approach leverages an intrinsic time-stepping description paired with a free wake model, making it a natural fit for generic rotary-wing configurations. A key aspect of this work is the excellent correlation achieved against a fully three-dimensional Boundary Element Method for potential flows. The work presents a comprehensive validation dataset. This dataset will span a variety of applications with unsteady harmonic motions for rotors in hovering conditions and extend to airplane mode axial flight conditions of proprotors, detailing the enhancements that have been briefly outlined here.