For more than a decade, the concept of the so-called More Electric Aircraft has been a key area of focus for technology development across the aerospace industry. Airframers and systems suppliers have been pushing for electrification of multiple aircraft functions to achieve savings in power and weight, replacing hydraulic and pneumatic power, while also simplifying maintenance and improving reliability.
More recently, though, aspirations have shifted to the advent of “all-electric aircraft” as concerns about the environmental sustainability of aviation, and a desire to exploit new business models, drive investment plans to develop aircraft entirely powered by electricity. Much of this effort is focused on the so-called eVTOL (electric vertical takeoff and landing) sector, involving anywhere between 150 to 200 new programs at various stages of development, ranging from pipe dreams to those within sniffing distance of achieving type certification. Many of these prospective aircraft are intended for the envisaioned urban air mobility market and many of them are being designed to be operated autonomously, without a pilot.
There are also plans for all-electric fixed wing aircraft, some of which aspire to supporting mainstream air transport operations. However, given the widely acknowledged limitations of existing battery technology, many of the new developments are geared toward hybrid electric powerplant combinations in which fossil-fuel-driven engines generate electricity that is then used to drive rotors and fans.
Many of the electric aircraft evangelists are start-up companies, and many of these have a somewhat tenuous connection to the aerospace industry—often being worshippers at the altar of Silicon Valley, rather than that of the Wright Brothers. According to a January 2019 report from the Vertical Flight Society, the new eVTOL programs alone have already attracted more than $2 billion in fresh investment, with much of this coming from venture capitalists. Multiple reports project value of the market rapidly advancing north of $300 billion within 20 years.
The new eVTOL designs are a mix of airframe configurations, including multicopters (with up to two dozen sets of rotors), lift-and-cruise, tiltwing, and tiltrotors. Some companies are exploring the possibilities of using hydrogen fuel cells as an alternative to electrical power, although these plans are generally not very mature, at least for now.
At face value, Zunum Aero, the Washington-state-based start-up founded in 2013 by former Google executive Ashish Kumar and aerospace engineer Matt Knapp, is an ideal marriage of Silicon Valley verve and aviation savvy. The stars seemed to be aligning when it received significant launch investments from Boeing’s HorizonX “innovation cell” and JetBlue Technology Ventures (a subsidiary of the U.S. airline group).
The goal had been to get its 12-seat ZA10 electric fixed wing aircraft in service by 2022, with a first test flight anticipated in 2019. In May 2018, charter group JetSuite was announced as launch customer for the program, having committed to 100 examples of the aircraft.
In the longer term, Zunum Aero has been laying plans for a family of aircraft carrying up to 50 passengers on sectors of up to around 700 miles by 2030. The company promised transformational operating costs of just eight cents per seat mile or $250 per flight hour.
But sometime around September 2018, both Boeing and JetBlue quietly pulled support for the program without explaining why. This triggered an increasingly urgent campaign to attract new financial backers and, as of early September, no such support had been lined up. Zunum Aero has declined to comment on how the timeline for its plans may be impacted by the apparent capital drought, but multiple media reports cite layoffs and other cost-cutting measures.
Zunum’s plans to lead the electric aviation charge may yet come good. Even if they don’t, there is clearly no shortage of other contenders and, apparently, other prospective investors still have a large appetite for getting a piece of the action.
Among start-ups, Germany’s Volocopter and Lilium appear to be gathering significant momentum in the eVTOL sector—or at least, they have been more transparent than most about how their plans are progressing. Meanwhile, established aerospace giants are progressing their own plans on several fronts. Meanwhile, China’s EHang has begun flight trials for both cargo- and passenger-carrying flights with its 116 and 216 models, and claims to have already logged more than 1,000 orders for what it calls Aerial Air Vehicles.
Airbus is in the advanced stages of flight testing its CityHawk and Vahana technology demonstrators and aims to be ready to confirm its plans to develop an eVTOL aircraft by the end of 2020. The European airframer has said it prefers to take time to address all aspects of what it will take to safely operate this new class of aircraft in urban environments, rather than rushing to be among the early market entrants. In its view, some start-up companies are succumbing to pressure from private investors to promise unrealistic timelines for getting aircraft certified and into operation.
Boeing’s year-old NeXt division appears to be hedging its bets in the eVTOL market. The U.S. aerospace group’s Aurora Flight Sciences unit has been developing its Passenger Air Vehicle, which made a first flight in January 2019. The prototype suffered a crash during its fifth flight on June 4, and, as of early September, had yet to confirm when flight testing would resume or how the development timeline might be affected. At the same time, Boeing has since announced a strategic partnership with start-up company Kitty Hawk to develop its Cora eVTOL aircraft.
Meanwhile, among the relatively conventional new generation of fixed wing designs, Bye Aerospace is making progress with its all-electric, two- and four-seat eFlyer aircraft. The company has started taking orders from charter operators, including Los Angeles-based Quantum Air, though terms of that order are unclear.
Eviation Aircraft is preparing to start flight testing its Alice electric pusher-prop prototype. The Israel-based company’s financial foundations were significantly bolstered in August, when Singapore-based investment group Clermont acquired a 70 percent stake. And U.S.-based Part 135 operator Cape Air signed on with a purchase option for "double-digit" numbers of aircraft for short-haul regional services.
This barely scratches the surface of the somewhat unfathomable number of new electric aircraft programs. Most of the contenders are rich on ambition and imagination, but quite how they will weather aviation’s unforgiving business environment is the big unknown.
At the Global Urban Air Summit held at Farnborough, UK on September 3-4, stakeholders from across the industry gathered to assess what it will take to make electric dreams come true. Sobering perspective was provided by a cross section of leading regulators who cautioned that not only will exacting certification standards need to be met, but also the sector faces challenges in winning public acceptance for air transport business models that will significantly stretch the boundaries of current convention.