Improved Mathematical Model for Helicopter Flight Dynamics Applications

This paper is concerned with the mathematical model development issues necessary for better prediction of dynamic responses of articulated rotor helicopters. The methodology is laid out based on mathematical model development for articulated rotor helicopters, using the theories of aeroelastisity, finite element and the time domain compressible unsteady aerodynamics. The helicopter is represented by a set of coupled nonlinear partial differential equations for the main rotor within nonlinear first order ordinary differential equations representation, describing the dynamics of the rest of the helicopter. The complexity of the formulation imposes the use of numerical solution techniques for dynamic response calculations. The validation is performed by comparing simulated responses to flight test data for a known configuration. The results show improvement in dynamic response prediction of both on-axis and crosscoupled responses of helicopter to pilot inputs.