Aerodynamic design optimisation for a helicopter configuration including a rotating rotor head

Aerodynamic drag is an important conside-ration in helicopter design to decrease fuel con-sumption and associated emissions. The project 'Aerodynamic Design Optimsation of a Helicop-ter Fuselage Including a Rotating Rotor Head' - ADHeRo -, within the frame of the European Community's Clean Sky Green Rotorcraft Con-sortium, aims to reduce parasite drag of twin engine light class utility helicopters. Performing comprehensive wind tunnel tests and numerical simulations, aerodynamic forces and moments, surface pressure distributions and wake flow fields are analyzed in detail for a specific base-line configuration. Shape modifications and means of passive flow control are applied to diminish flow separation and wake flow regions associated with high pressure drag. Conse-quently, two modified skid landing gears have been designed, namely a retrofit variant and a more progressive one. These modified skid landing gears provide an overall reduction in drag of 20.9% and 23.1%, respectively. In addition, solutions focusing on both vortex generators located at the fuselage belly ahead of the back door and port and starboard strake elements along the back door results in further drag reduction of 1.4%. Therefore, an overall drag saving of 22.3% is possible by adding retrofit parts designed within ADHeRo. The technology readiness level suggests that the corresponding configurations could be comer-cialised within a few years. Thus, ADHeRo is making an important contribution to reduce the environmental impact of light weight utility heli-copters along with lowering operational costs through reduced fuel consumption.