Airbus, Rolls-Royce and Siemens are partnering to develop hybrid-electric propulsion for commercial aircraft.

The E-Fan X hybrid-electric technology demonstrator could fly in 2020. It will be tested on a BAe 146 flying testbed, with one of the aircraft’s four gas turbine engines replaced by a 2 megawatt electric motor. A second gas turbine would be replaced with an electric motor once the system is proven.

Artist's view of the hybrid electric aircraft. Credit: AirbusThe E-Fan X follows a series of electric flight demonstrators, starting with the Cri-Cri, and including the e-Genius, E-Star and the E-Fan 1.2.

Airbus CTO Paul Eremenko said, “We see hybrid-electric propulsion as a compelling technology for the future of aviation.”

The E-Fan X demonstrator will test high-power propulsion systems, such as thermal effects, electric thrust management, altitude and dynamic effects on electric systems and electromagnetic compatibility issues. The objective is to push and mature the technology, performance, safety and reliability enabling progress to be made on the hybrid electric technology.

The program also aims to establish the requirements for future certification of electrically powered aircraft.

Airbus will be responsible for overall integration as well as the control architecture of the hybrid-electric propulsion system and batteries and its integration with flight controls.

Rolls-Royce will be responsible for the turbo-shaft engine, 2 MW generator and power electronics. Along with Airbus, Rolls-Royce will also work on the fan adaptation to the existing nacelle and the Siemens electric motor.

Siemens will deliver the 2 MW electric motors and their power electronic control unit, as well as the inverter, DC/DC converter and power distribution system. This comes on top of the E-Aircraft Systems House collaboration between Airbus and Siemens, which launched in 2016 and aims at developing electric propulsion system components and their ground-based testing across power classes.

The partners plan to meet the EU technical environmental goals of the European Commission’s Flightpath 2050 Vision for Aviation: reduction of CO₂ by 75 percent, reduction of NOx by 90 percent and noise reduction by 65 percent. These goals cannot be achieved with existing technology, the companies say.