Electric air taxis aim for American cities

Volocopter appears to be positioned toward the front end of a flock of newfangled aircraft being developed for short trips over city traffic. A dizzying array of electric vertical takeoff and landing (eVTOL) designs are in development, though none have yet been certified anywhere in the world. Volocopter hopes to be the first, with certification and commercial launch hoped for in the next two or three years, according to a January 15 news release announcing the firm’s intent to establish air taxi operations in (as yet unnamed) U.S. cities soon thereafter.

Keeping that schedule (and it is rare in aviation that any such schedule survives actual regulatory review) would put the VoloCity eVTOL about two years ahead of rival Lilium’s hoped-for certification of the Lilium Jet in 2025.

There are other contenders, many of them still on drawing boards, including a design unveiled by General Motors at the (virtual) 2021 Consumer Electronics Show, where a Cadillac-branded, single-seat eVTOL concept featured prominently in the company’s presentation. While this first flying Cadillac design may or may not ever be built, the concept nonetheless attracted media attention. Likewise, a partnership between California startup Archer Aviation and Fiat Chrysler Automobiles boosted the aspirations of another contender in the race to turn urban rooftops into flying-taxi stands.

Ride-sharing behemoth Uber once led the flying car charge, predicting in 2017 that a practical flying car would arrive by 2020. Instead, Uber marked 2020 by handing $75 million in cash, and ownership of Uber Elevate, to a California startup (with its own investment from the automotive industry) called Joby Aviation, which aspires to certify its own eVTOL design by 2022.

Joby reported having raised more than $800 million to help make that happen. Like Volocopter and Lilium (and notably unlike the flying Cadillac), Joby’s six-rotor, five-seat S4 is made to be flown by a pilot. While having humans at flight controls is virtually certain to win regulatory approval faster than the world’s first fully autonomous aircraft, a low ratio of paid crewmembers to paying customers makes the eVTOL business case look very familiar to aviation analyst Richard Aboulafia, vice president of analysis at Teal Group. 

“I think it’s been hiding among us in plain sight,” Aboulafia said of the urban air mobility business model outlined in various white papers (such as this one published by Uber in 2016) that present optimistic prognostications, and plans to make vertical-lift electric aircraft transportation an everyday reality. Traditional helicopters have already achieved an operating cost comparable to some more expensive automobiles. Robinson Helicopter calculates an R44 Cadet’s operating costs at $1.24 per road mile. 

Volocopter’s 2019 white paper entitled Pioneering the Urban Air Taxi Revolution offers few specifics on what it will actually cost to operate electric aircraft with life-limited batteries. Volocopter proposes charging batteries slowly to extend the life of what will almost certainly be the most expensive life-limited component on the aircraft, and reducing aircraft complexity compared to other eVTOL designs, and to traditional aircraft.

Still, to Aboulafia, the prospect of an “urban air taxi revolution” looks an awful lot like Part 135 helicopter operations of today, with less range.

“You could make an argument that noise may be a big enabler,” Aboulafia said, referring to an oft-cited selling point of electric aircraft: They are much quieter than anything powered by internal combustion. However, he added, noise sensitivity varies widely depending on location, and in many communities, it might not make much difference.

“I think to create a new bubble, to create a new technological bubble, you have to erase all memories of technologies that came before,” Aboulafia said. “I’m wondering if that’s not what’s going on here.”

Aboulafia said the fundamental economics of commercializing electric aircraft will remain very similar to petroleum propulsion as long as pilots are required, and aviation autonomy remains a long way off. “You’re talking about a 2040 and beyond possibility,” Aboulafia said of the prospect of aircraft carrying paying customers without pilots.

Physics also presents a problem that eVTOL engineers will need to solve to scale up, and they will need a hand from battery engineers. The energy density of currently available batteries remains about 50 times lower than that of petroleum-based fuels, as general aviation pilot and physics professor Peter Rez noted in the January issue of AOPA Pilot.

“If battery performance improves, and different battery technologies make it possible to increase the energy density, both fixed-wing and vertical-takeoff electrically powered aircraft would become more competitive,” Rez wrote. “But at the present time the 50-times advantage in energy density between avgas or jet fuel and the best lithium-ion batteries available [does] not compensate for the relative inefficiency of either piston or turbine engines.”

Accelerating climate change and a worldwide push to reduce carbon emissions may offset some of the drawbacks of electric propulsion for aviation.

Pipistrel, among the leaders in aviation electrification and the first aircraft maker in the world to certify an airplane that runs on batteries, the Velis, emailed a press release January 21 under an eye-catching subject line (“Electric Aircraft are on fire!”) reporting that 111 Velis aircraft were delivered in 2020, with another 70 on the order book. The Slovenian company plans to hire a second shift at the factory to keep up with demand.

“The future really looks good for electric aircraft and the Pipistrel Velis, which is going from strength to strength in both sales and use,” the news release states.