Bluecopter demonstrator – an approach to eco-efficient helicopter design

Abstract

The "BLUECOPTER DEMONSTRATOR" presented in this paper has been developed to prove the feasibility of future eco-friendly helicopter concepts and to demonstrate "green" technologies in-flight. The main objectives are: • Significant reduction in CO2 emission and fuel consumption up to 40%; • Noise reduction of around 10 EPNdB below ICAO §8.4.1 noise certification limits; • Development of "transversal" technologies allowing for serial applications to all helicopter classes. A major contribution to the improved efficiency and reduced acoustic emission of the BLUECOPTER DEMONSTRATOR is provided by the newly developed rotor system. It includes an innovative five-bladed bearingless main rotor with increased diameter, BlueEdge™ style blade shape, new twist distribution and low tip speed design. Moreover it features an advanced Fenestron® with an optimized blade and stator design. Several measures were applied to reduce the drag of the aircraft including fairings for the main rotor and landing skids, a special design of the aft-body and a low-drag empennage including a "T-Tail" horizontal stabilizer. Additional features like the active fin rudder and the "acoustic liner" for the Fenestron shroud have been applied to further improve the acoustic footprint of the demonstrator. The BLUECOPTER DEMONSTRATOR has been successfully flight tested in 2014 and will be further improved and tested in 2015. This paper gives an overview on the technologies proven in-flight and summarizes the benefits achieved in terms of performance and acoustic emissions.