The Blue Edge - Blade Continuation

Airbus is certifying new H160 helicopter, first serial application of the Blue EdgeTM rotor system, easily recognizable with its double leading edge swept shape. The reduction of the blade-vortex interaction noise has been the main driver of this design, studied since the 1990s, in collaboration between DLR, ONERA and Eurocopter (since become Airbus). From the project ERATO (Etude d'un Rotor Aeroacoustique Technologiquement Optimise = aeroacoustically optimized rotor), the Blue EdgeTM blade design became the trademark of the last rotor generation whose the history is summarized in Ref. 1. In 2014, a first extrapolation of this type of shape has been developed and tested in the frame of BluecopterTM demonstrator as described in Ref. 2. The five-bladed bearingless rotor flew on EC135 in order to explore a low tip speed within new optimized eco airfoils and twist distribution. At the same time, new studies of Blue EdgeTM design has been performed with other objectives: keeping the shape for the BVI acoustic reduction, multi-objective optimization of airfoils, twist and chord for better aerodynamic performances. This project, internally called PROTEGE (Pale pRincipale ecOlogique en composiTe de nouvellE GEneration – New generation of ecological composite blade), flew on H225 demonstrator. The paper presents an overview of the design development of this new blade and the results about the dynamic behavior, the aerodynamic performances and acoustic reduction in various flight conditions. The acquired results bring new elements in the Blue EdgeTM blade which strengthen the interest of this design for the BVI acoustic reduction.