Configuration and verification of a tandem rotorcraft in DLR’s versatile aeromechanics simulation tool MAECOsim®

Abstract

This thesis presents the configuration and verification of a tandem rotorcraft model in DLR's Versatile Aeromechanics Simulation Tool (MAECOsim®, formerly VAST). To address the need for simulation models of non-conventional rotorcraft configurations, a tandem rotor model based on the well-documented flight characteristics of the CH-47B Chinook is implemented and evaluated. The simulation framework combines a multibody system dynamics core with comprehensive rotor aeromechanics models, including Blade Element Momentum Theory (BEMT) and a Pitt-Peters dynamic inflow model. Special attention is given to the modeling of rotor-rotor and rotor-fuselage aerodynamic interference effects, which are critical for the flight dynamics of tandem configurations. A trim sweep in steady level forward flight from hover to 80 m/s is performed to assess the model's fidelity against historical flight test data provided by Ostroff (1976) and Bender (1984). The results demonstrate that the simulation environment successfully reproduces the characteristic trim trends of the tandem configuration in level forward flight, including control inputs and fuselage attitude. Rotor-rotor interference is identified as a dominant factor in the low-speed regime, while systematic offsets in power prediction are attributed to modeling simplifications such as the rigid-blade assumption. The study confirms the suitability of MAECOsim® for predictive modeling of multi-rotor configurations and provides a validated basis for future applications, including piloted simulations in DLR’s Air Vehicle Simulator (AVES).