Tim de Chant Ars Technica
Aviation in 2030: Fuel-guzzling supersonic planes or electric air taxis?
June 8, 2021
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  • Over the last two days, two companies have outlined radically different—yet oddly familiar—visions for the future of air travel.

    One idea is built around a buzzing network of small, electrically powered vertical take-off and landing (eVTOL) aircraft ferrying commuters in and out of dense urban areas, a tantalizing vision prophesied since at least the 1950s. The other vision bets on a fleet of a few dozen supersonic airliners jetting well-heeled travelers from one global city to another, a dream that many thought died with the Concorde some 20 years ago.

    Oddly, it’s the flying cars that seem closer to reality this time. Yesterday, Joby Aviation announced another step in its plan to bring eVTOL services to the masses. The company has signed an agreement with two real estate companies, Neighborhood Property Group and Reef Technology (the latter is a sort of WeWork for non-office commercial real estate), to allow rooftop access to Reef’s 5,000 parking garages in the US and Europe. By comparison, there are about 5,600 US heliports, which are managed by a patchwork of owners.

    Physical access is a perennial challenge in aviation. Traditional airplanes require a lot of space to take off and land, and helicopters need wide berths to protect people from their downwash. Plus, both jets and helicopters create a lot of noise. Joby is hoping its design solves the noise problem, at least. In a video released earlier this year, founder JoeBen Bivert stood before one of his company’s five-seat models, talking without raising his voice as the aircraft spun up and took off behind him. It’s not quiet, but neither does the aircraft appear to be helicopter-loud. Bloomberg reports that the noise is similar to a rooftop air conditioner.

    Joby’s eVTOL aircraft are quiet in part due to their configuration. Each is powered by six motors driving 9.5-foot diameter rotors. The lack of a gearbox reduces some noise, and a low tip speed during vertical flight eliminates more.

    Solving downwash is a trickier matter—to transport people, the craft needs to be a certain size, which means it has to move a certain amount of air to get it aloft. That’s probably why Joby has been eyeing the top levels of parking garages. Not only do they offer an open stretch of concrete in crowded cities, but they also are elevated above street level, reducing the influence of complex wind patterns in urban canyons.

    Joby is hoping to certify its aircraft in 2023, one year before it plans to roll out commercial services in cities like Los Angeles, New York, Miami, and San Francisco. What those initial operations will look like is still an open question, but the company has been working with Uber on some details. Joby took over Uber’s air taxi in December 2020, and the transportation network company has invested $125 million in the aviation startup. Uber plans to offer Joby flights through its ride-hailing app.

    Concorde redux
    Electric VTOL services for commuters couldn’t be more different from what United Airlines announced today. The company said it was ordering 15 jets from aviation startup Boom Supersonic, with the option to buy 20 more. Each supersonic plane costs $200 million, and since Boom does not offer discounts, which are typical elsewhere in the industry, the entire deal is worth $3 billion. (United has also expressed interest in eVTOL aircraft.)

    Boom Supersonic
    Boom anticipates that Overture planes will travel at up to twice the speed of conventional jetliners—up to Mach 1.7 over the oceans—slashing flight times. Flights between United’s Newark hub and London would drop from about six and a half hours to three and a half hours, and San Francisco to Tokyo would take just six hours instead of 10 and half hours.

    Denver-based Boom has raised $270 million in funding, but it will have to attract a lot more if it’s going to bring its Overture aircraft into commercial service—Boom’s CEO estimates that it could cost up to $8 billion. The company unveiled its demonstrator aircraft last year.

    Development expenses may not be the only costs that keep the Overture grounded, either. Many airlines were driven away from the Concorde by its high operating costs. The speedy airplane gulped jet fuel. Compared with contemporary 747s, the Concordes needed 11 times more fuel to carry similar payloads the same distance.

    Boom’s CEO says the company’s planes “will see overall fuel burn at parity” with business-class travel. Given the wide range of business-class offerings, it’s hard to derive an exact number, but one estimate pegs the Overture’s fuel consumption per passenger at around five times worse than a typical subsonic economy seat.

    To assuage passengers’ guilt of their potentially outsize carbon footprints, Boom says it is working with Prometheus Fuels, a startup that uses nanotube membranes to produce jet fuels from carbon dioxide drawn from the atmosphere. If paired with renewable energy, that partnership would let Overture flights have net-zero carbon emissions (though there would still be considerable NOx and particulate emissions). In today’s announcement, though, United and Boom did not commit to using so-called e-fuels, only saying that the planes would be capable of using sustainable fuels. Worldwide, the aviation industry is responsible for about 2.4 percent of carbon pollution.