Aerodynamic Interactions on Airbus Helicopters' Compound Helicopter RACER in Hover

In recent years, helicopter manufacturers have developed an increasing number of nonconventional configurations in order to extend flight envelopes of helicopters towards higher cruise speed. Airbus Helicopters' approach is the compound helicopter RACER, which is equipped with a boxwing and lateral pusher rotors. As the combination of these components with the main rotor induces a variety of mutual interactions, influencing their individual aerodynamic performance depending on the flight conditions, the understanding of these interactions is vital for the evaluation of the overall system. For this reason, the respective mutual influence of main rotor, wings, and lateral rotors is analyzed in this paper for hover. With the help of high-fidelity coupled aerodynamic simulations for the full RACER (Rapid And Cost-Efficient Rotorcraft) configuration as well as for setups omitting individual components, first- and second-order interactions of these components are isolated and analyzed for their effect on the helicopter's aerodynamic performance.