ONERA and DLR Contributions to Improve Environmental Friendliness of Rotorcraft

This paper is providing an overview of the ONERA and DLR results in the Clean Sky Green Rotorcraft project (2008-2016). An active twist technology and tools for passive blade design and optimization ranging from single to multiple objectives are presented for improving the main rotor blade performance. Technologies for drag reduction of non-lifting components (rotor head, blade stubs and fuselage) including active blowing, vortex generators and passive design show the potential of an overall drag reduction of slightly more than 6% (confirmed by wind tunnel tests). The design of noise abatement flight procedures and the corresponding flight tests are described obtaining up to 60% reduction of the area exposed to a certain noise level. Finally the interface between the Green Rotorcraft ITD and the overall Clean Sky JTI Technology Evaluator is described.