Three major companies are working together to create the E-Fan X, a demo version of a hybrid-electric passenger plane that is scheduled to take off in 2020. In this connection, Siemens is developing an electric propulsion system that will have two megawatts of power, and is thus expected to break existing records for lightweight drive systems. The propulsion system is taking shape in the context of an Airbus-Siemens collaborative effort that was launched in 2016. However, the E-Fan X itself will be developed outside of this context.
The Future of Mobility
Airbus, Rolls-Royce, and Siemens to Develop Flying Demonstrator
Siemens, Airbus, and Rolls-Royce want – for the first time – to test a hybrid-electric propulsion system in a relatively large aircraft. That’s what the three companies announced in November 2017. Basically a flying test platform, the plane, which will be based on a 100-seat BAe146, is scheduled to make its maiden flight in 2020. In our interview, Dr. Frank Anton, Head of Siemens eAircraft – a department in which the company has brought together all of its activities with regard to electric flight – and Wulf Roscher, project manager for E-Fan X at Siemens eAircraft, discuss this revolutionary project.
What does this project mean for Siemens in view of the company’s existing eAircraft activities?
Frank Anton: Following up on the kick-off of our partnership with Airbus in 2016, this large flying demonstrator will be a major step for eAircraft toward a hybrid-electric future. By testing the demonstrator and its electric propulsion system in flight, we will learn how to harness this disruptive innovation for aviation.
Thanks to our existing drive systems for drones and ultralight and light sport aircraft, we are already involved in aviation. Recently, we also presented a prototype motor for the CityAirbus, a flying taxi for use in urban areas.
We are now building on the experience we’ve gained during development of motors with these outputs in order to develop the first solution for a commercial aircraft: a hybrid-electric airliner that can seat 50 to 100 passengers. This development will enable passenger transport to become quieter and more sustainable.
What exactly are you planning?
Wulf Roscher: The electric propulsion systems that eAircraft has developed to date — our “world record drive system,” for example — have had outputs of up to one fourth of a megawatt (MW). But now we are developing a two-MW electric propulsion system for regional aircraft that will be about eight times more powerful than the system that drives our Extra 330LE. Four to eight such motors on the wings of a regional plane could power an aircraft’s propellors or fans. In the flying demonstrator, the electric propulsion system will obtain its power from a generator that will be powered by a turbine in the fuselage. Take-off and climbing will be supported by lithium-ion batteries, each of which will have 700-kilowatts of power.
Anton: Our intention is to replace one of the test plane’s four jet turbines with a two-MW electric propulsion system in time for the maiden flight, which is scheduled for 2020. That would be the first time that such a powerful electric motor would help to propel an airplane! We can imagine that in subsequent tests, we will replace an additional turbine with an electric propulsion system.
Wouldn’t such a powerful drive system weigh a lot and take up an incredible amount of space? Although electric mobility has many benefits, can such a drive system be efficient?
Roscher: Thanks to the extensive amount of research we have conducted in advanced lightweight engineering and high-tech materials, we expect to be able to drastically reduce the size and weight of our drives. Although our previous record-breaking motor achieved a continuous performance output of 5.2 kW per kilogram of motor mass, we want to significantly improve on this in our 2 MW motor.
Anton: The secret recipe is not materials or topology. The kinds of extremely light propulsion systems we are talking about can be developed and built only thanks to SimcenterTM, a Siemens PLM simulation suite software that takes all known physical and technical effects into account. Using this technology, we iteratively build digital twins and thus virtually optimize our prototypes. This not only accelerates development, but also results in more powerful machines.
What are the roles of the project’s partners?
Anton: Airbus will be in charge of overall integration and test flights and will deliver the energy storage systems. Rolls-Royce will provide a 2.5 MW turbine and integrated generator that will supply the electrical power for our electrical propulsion system. In addition to the electric motor for the inverter, Siemens will provide the energy distribution system. I think that by partnering, three major players are building a flying demonstrator that will bring us closer to my vision of flying across Europe in hybrid-electric passenger planes!
Dr. Frank Anton: His career began at an early age, when he became one of the winners of the Jugend forscht competition. He studied physics in Bochum, Bonn and Grenoble. At Siemens, he contributed to the advancement of technology by working as a particle accelerator developer, head of development for magnetic resonance tomography, managing director for surgical X-ray systems, head of sales for medical technology, and head of the traction power unit business He now heads the eAircraft startup unit, which is very fitting, as he is an avid aviator who likes to fly electrical test platforms himself.
Wulf Roscher is an electrical engineer who has been working for Siemens for the past 23 years. During this time, he has held a variety of positions related to Automation & Drives. For the past year, he has been eAircraft’s project manager for high-output drive systems. For him, this challenging position is much more than just a job. He sees it as a springboard for the large-scale reduction of dependence on fossil fuels, and thus a contribution to the health of our planet for future generations. In this context, his personal contribution to this goal takes place each day: he rides to work on a bicycle.