Racer High-Speed Demonstrator: Tail Unit Vertical Fin Aerodynamic Design

Within the framework of NACOR project in CleanSky 2 AIRFRAME ITD, ONERA and DLR performed parallel investigations dealing with the RACER high-speed demonstrator, and especially with its tail parts, each partner respectively focusing on vertical fins (ONERA) and horizontal stabilizer (DLR). The present paper focuses on ONERA's contribution to the rear part design: both new vertical fins and design recommendations have been provided based on a multi-fidelity approach. A large panel of performance assessment tools, shape modification and optimization strategies have indeed been used. A major shape modification of the vertical fin has first been proposed in order to tackle a flow separation issue. An optimization process then resulted in an optimized vertical fin aerodynamic design, which met all the constraints and achieved all the objectives. This strong cooperation between ONERA and Airbus Helicopters enabled this investigation to be successful, leading the final vertical fins protected by patent today.