Airbus is investing in hybrid and electric propulsion research in a bid to make flights quieter and cleaner.
In 1895, the prestigious Scottish physicist Lord Kelvin, then President of the Royal Society in London, asserted that “flying machines heavier than air are impossible.” But only 8 years later, on 17 December 1903, Wilbur and Orville Wright completed the first ever controlled flight of a powered aircraft, travelling for 12 seconds over a distance of 37 metres. On that same day in another test, they flew 260 metres in 59 seconds. It turned out that flying machines heavier than air were in fact possible.
The fact is that aviation has been pushing the boundaries of the impossible ever since its origins. And now it is doing so again, with Airbus at the forefront. The European multinational is researching hybrid and all-electric propulsion as a means of developing quieter and more sustainable aircraft.
As part of the Flightpath 2050 Vision, Europe aims to achieve a 75% reduction in CO2 emissions, a 90% reduction in NOx emissions and a 65% reduction in perceived noise emissions by 2050 compared to levels in 2000. These goals are unattainable using current technology; just as impossible as it was to fly according to Lord Kelvin.
Making impossible possible
Electric and electric-hybrid flight represent some of the biggest industrial challenges of our time.
“Electric propulsion is a necessary technological step in order to achieve CO2-free aviation,” explains mechanical engineer Martin Nüsseler, head of the E-Aircraft System programme. This project combines the efforts and know-how across Airbus to work together towards a more sustainable industry.
“Electric and electric-hybrid flight represent some of the biggest industrial challenges of our time, aiming at zero-emissions aviation,” said Tom Enders, CEO of Airbus, after signing a long-term cooperation agreement in the field with Siemens on 7 April 2016. “We believe that by 2030, passenger aircraft below 100 seats could be propelled by hybrid propulsion systems, and we are determined to explore this possibility together with world-class partners like Siemens,” he said.
By 2030, passenger aircraft below below 100 seats could be propelled by hybrid propulsion systems.
On that same day, the CEOs of both companies laid a symbolic foundation stone on the future site of the E-Aircraft System House, a research facility on the Ottobrunn site in Germany that will be used to test ground-breaking innovations in the field of electric aerospace mobility. Scheduled to open in late 2018, this facility will be jointly operated by Airbus, Airbus Helicopters and Airbus Defence and Space.
The research will focus on propulsion systems in three general power categories:
- Several hundred kilowatts, for applications such as helicopters and unmanned aerial vehicles;
- Up to 2 megawatts, typically applicable to intra-urban air vehicles;
- 10 to 20 megawatts for regional passenger aircraft.
“What’s so exciting about hybrid and electric propulsion systems is that they completely open the design space for new aircraft concepts, missions and potential market segments,” adds Nüsseler.
The E-Aircraft System House will be used to accelerate the advances made in recent years, exemplified by the historic E-Fan developed by Airbus Innovations, which on a sunny morning on 10 July 2015 became the first twin-engine electric aircraft to cross the English Channel with test pilot Didier Esteyne aboard. This two-seater aircraft weighing barely 500 kilogrammes flew the 74 kilometres separating the English coast from Calais, France, in 37 minutes without emitting any CO2 or NOx.
“The current aim of the E-Fan programme is to design, develop, build and bring to market an all-electric trainer aircraft,” explains Emmanuel Joubert, technical leader of the project at Airbus. “We’re discovering how important it is to consider all the operational concepts, which may be very different to those of current conventional aircraft. For example, the ability to recharge the battery in 50 minutes on the ground is a crucial factor with a major influence on the design and specifications,” he says.
According to Joubert, the E-Fan 2.0 will probably be “the first electric aircraft to be certified by the European Aviation Safety Agency, which represents an enormous milestone.”
In search of a breakthrough
The main challenge is how to store the necessary energy in batteries,” says Rainer von Wrede, aviation and environment expert at Airbus. Current lithium-ion batteries have only a small fraction of the energy density of kerosene, the traditional aircraft fuel. “And the bigger the aircraft, the bigger the challenge. To give an example, if we were to fill up an A320 with the best batteries available on the market today, without any passengers or fuel, the aircraft would only be able to fly for 10 minutes,” says von Wrede.
“We’re headed in the right direction,” says aeronautical engineer Gerhard Wolf regarding the new synergies arising between the company’s different divisions. Wolf, who is head of strategic value streams at Airbus, stresses that the objective is “to steadily increase the level of electrification, starting with the secondary power supply for areas such as the flight controls and the air conditioning.”
A hybrid solution
We all need to be ready to rapidly adopt any innovation that can radically change the current state of things.
“When people hear about electric flight,” Wolf continues, “they think of electric batteries and motors. But there’s an intermediate stage with tremendous potential: hybrid propulsion systems.” Like the hybrid vehicles that are revolutionising land transport, a combination of two engines – one combustion engine and another electric engine – could reduce emissions and noise levels while at the same time maintaining the necessary power and performance. “Nowadays we obtain 10% of energy using electric batteries and 90% using fuel, but several generations from now, say in 20 or 30 years, we may progress to 90% electric and 10% fuel – who knows?” Wolf sums up.
Nüsseler is optimistic. He is aware, unlike Lord Kelvin, that the future is unpredictable. He also knows that you have to be prepared. As history has shown, what is impossible today may be possible tomorrow. Indeed, it might have to be.
4 questions to Siemens CTO Siegfried Russwurm
Why is Siemens interested in partnering with Airbus in the quest to electrify flight?
We see Airbus as the only viable partner to jointly reach the Flight Path 2050 CO2 and noise targets. These simply cannot be attained without switching to hybrid or fully electric systems. Airbus has enormous expertise in aircraft design and manufacturing, and we want to apply our expertise in electric drives to this exciting field. Siemens and Airbus have already collaborated in the past: in 2011 and 2013, experts from Siemens, Airbus and Diamond Aircraft presented their DA 36 E-Star motorised glider with different serial-hybrid drives. It was a milestone for the future of aviation with fewer emissions, lower noise levels and higher operating efficiency.
Why have you decided to carry out electric research through your new incubator, next47?
next47 is much more than an incubator: our new entity also carries out corporate venturing in selected innovation fields. For high-potential projects, we partner with start-ups and large companies alike on ‘moonshot’ projects, such as the one with Airbus, as well as other smaller-scale projects. We look at the disruptive factor of the project. Projects such as the electric plane go beyond any regular research project both in size and complexity. next47 offers the flexible and responsive environment we need to reach the targets we’ve set ourselves.
What role will start-ups play in speeding up the development of technologies needed?
The overall success of the project will depend on many factors and the contributions of several partners. Our job is to bring all of the expertise together to help achieve a breakthrough. In order to do that, we assemble the best teams for the project, regardless of their nationality. Start-ups offer a wealth of talent that we need to make our vision a reality.
Just how far away are we today from the breakthrough needed to actually power a regional aircraft?
Based on our joint development roadmap, we expect a 50 to 100-seater – which will fly with a hybrid electric system over a distance of 1,000 kilometres – to become real by 2035.
Airbus' electric research milestones
E-Genius makes its maiden flight
This two-seater electric aircraft was built by the University of Stuttgart and co-funded by Airbus
E-Thrust hybrid concept is born
Airbus begins work with Rolls-Royce on distributed electrical aerospace propulsion, resulting in the E-Thrust hybrid concept
E-Star takes to the skies
In a cooperation supported by Airbus, the two-seater Diamond Aircraft DA36 E-Star motor glider takes to the skies, powered by an electric motor
E-Fan 1.0 makes its first flight
The E-Fan 1.0 is an all-electric twin propeller aircraft
Another E-Fan 1.0 feat
The E-Fan successfully crosses the English Channel
E-Fan ‘Plus’ demonstrator makes it debut
This hybrid testbed combines the energy of lithium ion batteries with a flight range-extending thermal engine
E-aircraft system house site takes shape
Airbus signs MOU with Siemens and lays a foundation stone on the future E-Aircraft System House site
Vahana takes to the skies
Vahana is the name of A^3’s electric self-piloted vehicle. The first flight will take place late 2017, followed by productization in 2020
E-aircraft system house opens
The site will serve as the Group’s electric aircraft research hub
Regional aircraft could be propelled by hybrid propulsion
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