From Schiphol to Milan, Munich or Manchester. Or another destination within 800 kilometers of Amsterdam. With ninety passengers, in a 'green' battery-powered aircraft.
Such a flight will never get off the ground, critics of electric flying have been saying for years. Flying on batteries sounds sustainable, but in practice the batteries are so heavy that you can't get any further than a flight in a two-seater from Schiphol to Lelystad.
Those who want to make aviation greener would be better off focusing on more sustainable fuel for conventional aircraft, critics say. Or you have to work on faster routes through European airspace. That saves CO2.
It is precisely this prevailing view that the founders of the Dutch start-up Elysian are fighting against. “Aviation should not write off battery-powered flying too quickly,” says Daniel Rosen Jacobson, one of the three initiators of Elysian. “Battery-electric flying is certainly possible on a commercial scale.”
Rosen Jacobson speaks via video link from Orlando, Florida. He is in the US with co-director Rob Wolleswinkel to present their plans for battery-powered flying. They will speak at a well-attended conference of the American Institute for Aeronautics and Astronautics (AIAA).
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On Wednesday afternoon American time, Wednesday evening in the Netherlands, they will show the first design of the electric aircraft that Elysian wants to bring to the market in 2033: for ninety passengers, maximum range of 800 kilometers. The company regularly talks to airlines, but it is still far too early for sales conversations, says Rosen Jacobson.
At the AIAA meeting, Elysian will also present two scientific articles about his plans. These should substantiate the claim that battery-powered flying is possible on a larger scale than previously thought. Wolleswinkel and the third man on the board, PhD aviation scientist Reynard de Vries, wrote the articles with researchers Maurice Hoogreef and Roelof Vos (TU Delft).
Breeder
The conference in Florida is a special moment for Daniel Rosen Jacobson. After a career at Google and the sale of his online video company, he started working for his father Jaap a few years ago. He gained fame in the 1980s and 1990s as a successful 'business doctor'; he reorganized and sold moribund companies.
Moreover, Jaap Rosen Jacobson was the man who continued to invest in (parts of) the Dutch aircraft manufacturer Fokker with his Panta Holdings. His long-standing dream: building a modern and efficient aircraft in the Netherlands.
Rosen Jacobson senior died last summer, aged 73. Son Daniel is now continuing to build on his father's dream. “It is special. All of Panta's work, knowledge and effort has led to where we are today.”
Panta, together with French investor Caravelle, has invested a total of 10 million dollars (9.1 million euros) in Elysian. According to Daniel Rosen Jacobson, the design and construction of their aircraft will ultimately cost 5 to 8 billion euros. Elysian has planned a new financing round at the end of 2024 or early 2025.
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Hydrogen
Major aircraft manufacturers such as Airbus and Boeing prefer to concentrate on flying on hydrogen or more sustainable kerosene rather than on electric aircraft. Why does the Dutch start-up, founded in 2023 and engaged in research since 2020, think it can make a battery-electric aircraft? A commercially attractive aircraft – both in terms of capacity and range – that airlines want to buy?
Technical director Rob Wolleswinkel, who worked for years at strategic consultancy Boston Consulting Group (BCG) and now flies business jets as a pilot, explains: “The battery is always called the biggest problem,” he says from Orlando. “It is heavy and provides relatively little energy per kilogram of weight that you have to carry.” But that, says Wolleswinkel, is especially a problem if you want to equip a device like the one currently used with an electric motor. Such an aircraft is designed based on the most modern technology, the latest economical engines. “If you reason from those relationships, you won't get anywhere. You have to look at the electrification of an aircraft very differently.”
Wolleswinkel prefers to look at the first generation of jet aircraft, such as the Boeing 707 or DC8. “They had the same problems as we now have with battery-electric aircraft.” Those old jets were heavy and had to carry a lot of fuel at take-off, up to half of it take-off-weight.
Design choices
Aircraft manufacturers solved the problems at the time with smart design choices. And so Elysian also wants to build its first electric airplane. Wolleswinkel et al., for example, want to place the batteries in the wings to make the construction of the aircraft lighter. “This puts the burden on the elevator is generated where the aircraft gets its lift, and uses the available space within the wing.”
The company assumes an aircraft with eight small propellers. Not two or four larger ones, as you see with other builders of electric or hybrid (part electric, part fossil fuel) aircraft. The Dutch Maeve Aerospace is building a hybrid aircraft with two propellers; the Swedish Heart Aerospace has so far opted for four.
“We distribute the power with eight propellers,” says Wolleswinkel. “The diameter of the propellers is smaller, the wing can then be attached lower to the fuselage and the landing gear is then shorter and lighter.”
The wings of the Elysian aircraft are large compared to the fuselage, larger than a conventional aircraft. “In this way we increase aerodynamic efficiency,” says Wolleswinkel. The wide wings do have folding wingtips; otherwise a device will not fit the gate.
Hot potatoes
The energy density of the batteries and their weight are not our biggest concerns, Wolleswinkel and Rosen Jacobson emphasize several times during the video call. Elysian uses batteries that can store an amount of energy of 360 Wh (watt hours) per kilogram of battery. That is more than double the energy that you could store in an 'airworthy' (light and safe) battery two years ago, according to the Fact sheet Sustainable alternatives to kerosene from TU Delft. However, this is only about a fortieth of the energy you get from a kilo of kerosene. But, the Elysian men also say, our efficiency is higher than flying on hydrogen.
Wolleswinkel believes in the development of batteries, in the “rat race” that is currently going on. “A battery with an energy density of 360 Wh per kg is not the generation of today, but of tomorrow. And not from the day after tomorrow or the distant future.” In China, aircraft manufacturer Comac presented a prototype of 500 Wh/kg last year.
Rosen Jacobson and Wolleswinkel say from Orlando that they drew up a list of their biggest problems last year. Wolleswinkel: “We call it our 'list of hot potatoes'. We have said this so often that American interlocutors are also talking about the hot potato list.”
That list includes: how do you connect the battery cell packs to the motors? What do you do with the heat that is released? How do you ensure that the batteries are placed in the wing in such a way that batteries can be replaced every six to twelve months? Which backup energy system does the company choose if an aircraft has to divert to another airport? And what system does it build to charge an aircraft at an airport within 45 minutes – eventually 30 minutes?
Enough hot potatoes, you might say, for any doubts about electric flying. Not with Daniel Rosen Jacobson: “Some hot potatoes are now a lot less hot than a while ago. I am convinced that we can compete with popular aircraft such as the Boeing 737 and the Airbus A320.”
Flights of up to a thousand kilometers make up half of all flights worldwide, the Elysian men emphasize. And those short flights account for a fifth of all aviation-related CO2emissions. Rosen Jacobson: “Electric flying will drastically reduce the impact of aviation on the climate.”
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