A High Fidelity Simulation Model for Comprehensive Analysis of Rotorcraft Towing Operations

This paper describes a high fidelity simulation model for rotorcraft towing operations. The towed body is modeled with six degrees of freedom for both translational and rotational dynamics. Fully coupled nonlinear hydrodynamic forces and moments are computed for the towed body including the loads acting on the lifting/control surfaces installed on the body. The model uses a towing cable module which consists of multiple nonlinear spring-damper elements to allow for cable curvature effects due to the distributed towing cable weight. A dual medium transition module was also developed to model the towed body dynamics during the transition from air into water or vice versa.