EADS is demonstrating here at Le Bourget a number of electric- and hybrid-propulsion technologies developed under its commitment to reduce aircraft CO2 emissions. In cooperation with Royan Aero Composites, EADS has developed and built the E-Fan fully electric general-aviation training aircraft and, separately, has engineered with Diamond Aircraft and Siemens the Diamond Aircraft DA36 E-Star 2 hybrid-electric motor-glider. EADS also cooperated with Rolls-Royce on the future distributed-propulsion system concept, and all three projects are dubbed “E-aircraft.”
Such developments are part of EADS’s research to support environmental-protection goals in the European Commission Flightpath 2050 report. Compared with environmental standards set in 2000, that plan aims to reduce aircraft CO2 emissions by 75 percent NOx by 90 percent, and noise by 65 percent.
EADS Innovation Works, the group's research and technology network, is developing environmentally friendly propulsion technologies that it hopes will provide components for EADS’s operating divisions. The two-seat E-Fan represents a strategic aviation-research step, according to chief technical officer Jean Botti. “We are committed to exploring leading-edge technologies that will yield benefits for civil and defense products.”
The E-Fan is 6.7meters long with a 9.5-meter wingspan and sports several innovations: two 0.75-kN electric motors using energy from two wing-located battery packs; ducted fans to reduce noise and increase safety; electric power for taxiing and takeoff; and Fadec-controlled engine.
EADS Innovation Works is developing the electric and propulsion systems with Royan, which performed aerodynamic studies and is building the all-composite structure and mechanical systems. French materials-research laboratory Critt Matériaux Poitou-Charentes, academic consortium Institut Supérieur de l'Aéronautique et de l'Espace/École Nationale Supérieure de Mécanique et d'Aérotechnique and C3 Technologies produced the wing.
Electrical engineers at Astrium and Eurocopter helped EADS Innovation Works test the battery packs, while the livery was designed by Airbus. The E-Fan is co-funded by France’s DGAC, the European Regional Development Fund, the French Government and local French authorities in the Région Aquitaine and Département Charente-Maritime. “We believe that the E-Fan demonstrator is an ideal platform that could be matured, certified and marketed for pilot training,” said Botti.
Diamond Aircraft's two-seat DA36 E-Star 2 motor-glider was introduced here two years ago. Since then it has been updated with a smaller, lighter Siemens electric motor and now weighs 100 kilograms less. Electricity comes from a small Austro Engine Wankel rotary-driven generator.
Since last year, EADS Innovation Works has worked with Rolls-Royce and Britain's Cambridge and Cranfield Universities on the Distributed Electrical Aerospace Propulsion (DEAP) program that could power future airliners. The project, which is co-funded by the UK’s Technology Strategy Board, uses six electric fans–distributed in clusters of three along the wing and fed by a common intake duct–that are expected to improve fuel economy and reduce gas and noise emissions.
An advanced gas turbine provides the fans' electric power and recharges the energy-storage system, which could be based on lithium-air technology, according to Rolls-Royce. “During climb, the distributed fans draw power from the energy-storage system, but during descent act like wind turbines to generate electrical energy, which recharges the batteries,” said the engine manufacturer.
For the megawatt power levels required by an electrical distributed-propulsion network, Rolls-Royce said a new “high-power superconducting electrical system will have to be designed and validated, based on cryogenic cooling at temperatures as low as –252 degrees C.” A major benefit claimed for such systems is that they can be integrated into the airframe structure to maximise aerodynamic efficiency and optimise the surrounding airflow, according to Rolls-Royce. “This reduces weight, drag and the amount of noise [the aircraft] makes.” Distributed propulsion “optimizes the overall system integration,” concluded EADS Innovation Works chief Sébastien Remy.