EADS Innovation Works has unveiled a concept helicopter featuring a diesel-electric hybrid propulsion system that it claims has the potential to halve fuel consumption compared with a typical twin-turbine helicopter such as the Eurocopter EC135.
One of several research projects being pursued by Innovation Works under the "eCO2avia" banner, EADS says the next step could be to build a flying prototype.
"The architecture of the system enables a number of features that reduce the power demand, and therefore fuel consumption," the company says.
The concept helicopter uses two opposed piston opposed cylinder diesel engines supplied by EcoMotors International of the USA to generate electrical power for the main and tail rotors. A power electronics unit controls energy flows for maximum efficiency.
"This means that the main rotor can be tilted forward so that in cruise flight you get forward thrust, but the body of the helicopter is in the minimum drag position," says EADS. "The tail rotor could also be turned off in cruise flight," it adds, as an aerodynamic surface can be used to maintain directional control.
The engines alone are around 30% more fuel efficient than today's turbine engines, while other weight savings and aerodynamic improvements facilitated by the hybrid architecture increase the total potential fuel saving to 50%, says EADS.
Another environmental and safety benefit is that a helicopter could, for example, take off or land quietly next to a hospital using electrical power from on-board batteries without the diesel engines running.
"Several different kinds of combustion engines could be integrated into such a hybrid system, which is one of many examples of the research efforts undertaken by the EADS group towards achieving the aviation industry's climate protection goals," says the company. The concept has been developed with input from EADS subsidiary Eurocopter.