Some people say the electric aircraft revolution has arrived. Others say: "Hogwash!"
But none can deny that chatter about electric aircraft – which invariably involves discussion of air taxis and electric take-off and landing aircraft – intensifies at every EBACE.
Electric aircraft and environmental sustainability were central topics discussed at EBACE's opening keynote session on Tuesday morning.
Advances in electric systems and VTOL design are "quickening the pace of innovation", European Business Aviation Association secretary-general Athar Husain Khan told attendees on Tuesday morning.
"Nowhere is it more prevalent than in business aviation," he added.
Khan urged the industry to work towards "improving the perception of business aviation" by embracing sustainable fuels and other steps to address environmental sustainability.
Keynote speaker and Volocopter chief executive Florian Reuter insisted that his company’s eVTOL aircraft will be able to help alleviate congestion in the world's major cities.
The German company has developed the 18-rotor, two-passenger Volocopter 2X.
"No matter where we go, we realise we have a problem," he said. "Cities are faced with severe mobility challenges."
Recent advances in distributed electric propulsion systems, battery density and autonomous technology have converged to make eVTOL aircraft viable, Reuter added.
"All these trends together make possible what wasn't possible before," says Reuter. "We believe this is the perfect viable product to get started."
Electric propulsion was also the topic of a panel discussion on Tuesday, while a session today focuses on eVTOL and urban air mobility, the idea that small air taxis could one day carry passengers through the skies of crowded cities.
This year's EBACE has also seen an emphasis on reducing CO2 emissions, with 27 aircraft arriving at Geneva powered by biofuel over the weekend.
Other eVTOL types highlighted at EBACE include the Ehang 184, made by Chinese company Ehang in partnership with Austrian composites company FACC.
The companies have built and flown their prototype and are working towards European certification, says FACC marketing and communications representative Tamara Leitner.
The beauty of eVTOL aircraft lies partly in their simplicity. Unlike helicopters, many do not need complex and heavy components such as cyclics, collectives, gearboxes, swashplates and transmissions.
The designs typically involve single distributed electric propulsion systems powering multiple small motors turning fans or propellers. Those motors can be housed in tilting ducts or incorporated into wings, minimising drag.
The eVTOL industry is now riding a wave of optimism – the "hype" stage, Vertical Flight Society executive director Mike Hirschberg said at the HAI Heli-Expo show in Atlanta in March. Everyone, it seems, is talking about electric aircraft, and some companies are promising to fundamentally transform travel.
But the hype could be transformed into disillusionment under the weight of real technological and regulatory challenges, followed by a period of "enlightenment" during which challenges are overcome, he says.
As envisioned, air taxis would need both physical infrastructure – a network of landing pads – and digital infrastructure linking aircraft, landing pads and passengers.
Also, the best lithium-ion batteries have an energy density of about 260Wh/kg – almost one-fiftieth the density of jet fuel. That means electric aircraft have limited weight and range.
Many people associate eVTOL aircraft with Uber Elevate, which has set ambitious goals for establishing an urban air taxi network. But dozens of companies are in the all-electric and hybrid-electric game, including major airframers.
Airbus is developing an eVTOL vehicle called the CityAirbus, Embraer revealed its concept for an eight-rotor eVTOL last year and Boeing flight tested an electric air taxi in January.
Likewise, Bell made a splash showcasing its Nexus air taxi concept, also at at HAI Heli-Expo in March, and Sikorsky announced at the same event that it is developing eVTOL technology in partnership with corporate sibling Otis Elevator Company and The Spaceship Company, which manufactures vehicles for Virgin Galactic.
Others include Munich-based start-up Lilium, which has flight tested a prototype of a five-passenger fixed-wing taxi called the Lilium Jet. With 36 all-electric tilting motors embedded in the flaps of the aircraft's wing, Lilium Jet will have 162nm (300km) range and a be capable of speeds of around 162kt (300km/h), according to the company.
Several companies are pursuing designs for fixed-wing electric aircraft. In March, Canadian seaplane operator Harbour Air said it plans to convert De Havilland Canada DHC-2 Beavers into all-electric aircraft powered by MagniX magni500 motors. Harbour says the technology perfectly suits its flights, which average about 30min, and expects to fly a Beaver with the motor later this year.
Meanwhile, Eviation Aircraft is developing Alice, an electric fixed-wing, nine-passenger commuter and business aircraft with an estimated 565nm range. Eviation projects first flight of Alice in autumn of 2019, with certification expected in 2021 and service entry in 2022.
The supply chain is also in the game.
In March, United Technologies (UTC) launched "Project 804", an effort to develop a hybrid-electric propulsion system to replace one of two turboprops on a Bombardier Dash 8-100. That effort could help develop systems for business or commercial aircraft, Collins has said.
UTC subsidiary Collins Aerospace also announced this year a $50 million investment to build an electric aircraft systems laboratory.
CFM International and Pratt & Whitney also have sights on electric propulsion. They view hybrid-electric systems, with gas turbines powering multiple fans, as eminently more feasible than fully electric systems for anything but small aircraft.