Up, up and away!
Image credit: Joby Aviation
Hybrid-electric vertical take-off and landing vehicles could transform the air traffic ecosystem.
After more than a decade, the market for electric vertical take-off and landing (eVTOL) aircraft is on the rise, and its goal of making urban air mobility (UAM) for everyone personal, on-demand and carbon-free looks within reach.
Big money is backing air taxis. This year, at least four leading players will go public. All will reverse-merge into existing listed investment vehicles – or SPACs – which will receive funding from current and new investors.
The deals will take the companies’ resources beyond a $700m (£500m) threshold, defined by Lufthansa Innovation Hub as the “minimum estimated capital threshold needed for successful development, certification and industrialisation of air taxis”. Others look set to follow as the sector consolidates.
Of the four front-runners, two are American: Joby Aviation, considered eVTOL’s most advanced (raising $6.6bn), and Archer Aviation, which just unveiled its Maker technology demonstrator aimed at seeding certification ($3.8bn). One is from Germany: Lilium, with an eVTOL jet that may be the first to compete in commercial aviation ($3.3bn). The fourth is from the UK: Vertical Aerospace ($2.2bn).
Vertical may be seeking the least capital but made the next most striking announcement – it has clients. It has received conditional orders from American Airlines (up to 250 of its VA-X4, with an option for up to 100 more), aircraft leasing group Avolon (up to 390; 190 on option), and Virgin Atlantic (50; 100 on option).
Following an earlier $1bn (£715m) conditional order United Airlines placed with Archer, airline clients help to validate one of the first likely markets for eVTOLs: short-distance airport transfers. The eVTOL companies have had to demonstrate that these are technologically feasible and can be priced at a comparable level to an Uber Black limousine service, tapping the lucrative business traveller segment. The eVTOL is not just a rich man’s ferry like a $1,000-an-hour helicopter. Economies of scale must later mean that all of us can use them.
Vertical has been busy elsewhere in the eVTOL ecosystem, too.
It has partnerships with Rolls-Royce for its all-electric powertrain, Belgium’s Solvay for composite structures and adhesives, Microsoft for cloud support and Honeywell for flight deck avionics. Earlier this year, it joined a ‘regulatory sandbox’ set up by the Civil Aviation Authority, alongside Heathrow and London City Airports, another German eVTOL pioneer Volocopter (also considering a SPAC), and a more aviation-familiar eVTOL player, Brazil’s Embraer.
It is good to see a UK company making this kind of headway. But Vertical is an example of something happening more widely, its order numbers notwithstanding. The market has moved beyond basic innovation to the integration phase.
The dream is for electric aircraft to replace fossil-fuel jetliners. But eVTOL’s first targets are regional public transport and more heavyweight logistics than seen in drone home-delivery projects like Amazon Prime Air. Speeds up to 200km/h and ranges up 300km/h are cited, but most aircraft will operate at the lower end of those benchmarks, with payloads roughly between 400kg and 2,500kg and two to six passengers.
Terminal transfers are just the beginning. Beyond that, with the United Nations forecasting that 68 per cent of the world’s population will live in cities by 2050, there are also prospects of short hops within and between cities carrying people, or ‘middle-mile’ freight from out-of-town distribution centres to downtown hubs. Off-road, on-time, in comfort from your local ‘vertiport’.
The industry has delivered the technological demonstrators to affirm the viability of scaled-up distributed electric propulsion. Joby, founded in 2009 and therefore eVTOL’s granddaddy, says it has completed more than 1,000 test flights in the last decade and advanced its research to the point where it recently agreed G1 certification aircraft conditions with the US Federal Aviation Authority (FAA). That milestone, passed in February, paves the way for its eVTOLs to enter commercial service by, it hopes, 2024.
As it passed, founder JoeBen Bevirt sounded a slight note of caution: “While we still have several years of aircraft testing ahead of us, we now have a clearly defined, and achievable, path to certifying our aircraft and introducing customer flights.”
‘While we still have several years of aircraft testing ahead of us, we now have a clearly defined, and achievable, path to certifying our aircraft and introducing customer flights.’
Bevirt, perhaps more than any other eVTOL leader, knows how much systemic complexity his market faces. Joby’s SPAC aims to raise the largest amount not just to get its aircraft accepted, built, and sold, but run a complete service. Its ambitions go as deep as the booking and management of flights, to which end it acquired Uber Elevate in late 2020 (Uber has invested $125m (£89m) in Joby to date). That $6.6bn (£4.7bn) will have to go a long way.
As another example, its most recent ecosystem partnership saw Joby link with REEF Technology to identify vertiport sites. Significantly, REEF is the US’s largest car-parks operator. This is about where to go and where to go from.
Innovative work is going into developing dedicated vertiports, but to kickstart the eVTOL market, emphasis is first on repurposing existing locations.
Archer also wants a 2024 launch. Its co-CEO Brett Adock says: “For take-off and landing sites, we’re using existing real estate with light retrofitting, and that includes helipads, and others such as rooftops, land parcels and parking lots.”
Meanwhile, the eVTOL operators are moving beyond prototypes to integrate more technology from existing aviation suppliers (in the latest deal, Lilium has announced another avionics agreement with Honeywell). That should further improve performance and, often underrated but important, add technology that is more familiar to regulators.
This is leading the main players towards a system rather than a service or hardware provider model. Roland Berger consultants cited three reasons in a recent report: “One, it allows them to understand the whole ecosystem and the integration of the different parts. Two, because the industry situation is still dynamic, the knowledge and vertical integration gained as a system provider allows players to react quickly to developments. Three, supply chains are not yet fully established.”
‘For take-off and landing sites, we’re using existing real estate with light retrofitting, and that includes helipads, rooftops and parking lots.’
There is another truly systemic factor of at least equal importance: regulation.
Morgan Stanley is a leading eVTOL investment rainmaker. It remains bullish. But earlier this year it cut its forecast for the total available value of the UAM market by 2040 from $1.5tr (£1tr) to $1tr (£715bn).
“We want to temper the extraordinarily large addressable market potential with nearer-term hurdles related to regulation and certification,” the firm said, quoting an FAA expert who told its researchers “A pitcher of Kool-Aid is best served with a side of Curmudgeon.”
As Joby’s work towards G1 shows, eVTOL companies have worked closely with regulators such as the FAA, CAA, and the European Union Aviation Safety Agency. Yet despite serious progress, there are tricky challenges. One of the trickiest is air traffic management (ATM).
The FAA and Nasa have worked with companies to develop a 1.0 Concept of Operations (ConOps) that paves the way for the use of piloted eVTOLs in ‘UAM corridors’. In the UK, Attitude Angel, a leader in the development of unified traffic management (UTM) platforms for urban aviation, is part of a government-backed vertiport pathfinder in Coventry later this year, with Urban-Air Port and Safeguard Vertiports. Embraer has launched a subsidiary, Eve Urban Air Mobility Solutions, that is also working on ConOps.
Dovetailing eVTOLs into ATM systems will be difficult and will probably involve automating what has traditionally been a human-led task while maintaining safety. Some of the challenges currently resist fast-track parallel modelling in the real world and digital twins, an important aid now for autonomous cars.
Joey Rios, aerospace research engineer at Nasa Ames and the lead software architect for its recent UTM project, explains that elements remain which must be analysed in the field. Alongside managing rapid changes in an urban landscape (e.g. construction cranes) and the microclimates that can be developed among densely packed skyscrapers, he also cited the radio-frequency issues in a city centre.
“Turns out if you fly near an apartment building, there’s a lot of people with Wi-Fi routers, and if you’re in conflict with that, you may have trouble communicating with your drone. These are known issues, but actually taking a look at it in a real urban environment was important,” he told Nasa in Silicon Valley.
Then there is the question of public acceptance, where the picture is still not that clear.
Studies by Nanyang Technological University in Singapore found that “the public is not as keen for [drones] to be used to provide services around their living spaces... However, they are more accepting of drones being used in areas like recreational spots or industrial areas.” That is from one of the world’s most technology-friendly societies.
Similar studies by the German federal government-funded Sky Limits project found that “most respondents were opposed to the use of delivery drones and air taxis”. Support for air taxis reached only 21 per cent for general passenger transport. Germany, along with the US, is seen as leading the way in eVTOL regulation.
The eVTOL companies believe the issue is one of education, and a further survey from another significant player, Boeing-backed Wisk, claims to show that once the public understand and then see what eVTOLs can do, acceptance rates rise. At the moment, however, it remains a case of take-your-pick.
All this is on the flight plan before you even talk about autonomous eVTOLs, the ultimate objective. Most proponents accept that they will have to train pilots (although they also know that trying to sell such careers when pilotless operation may indeed be but a decade away could be a challenge).
Then, of course, there is battery density, although current energy at 250Wh/kg will, Archer argues, get the commercial market under way. Here, a shift from lithium-ion to lithium-sulphur could help, however.
Let’s not get too negative. The real question is perhaps whether projections of 2024 for the start of commercial services is realistic. That date has slipped before. Joby initially wanted to be in the air by 2023. Because, assuming the system issues can be addressed – and with autonomous cars as another pathfinder – the potential is there.
Roland Berger has a short-term estimate of $90bn (£64bn) in revenues for passenger drones by 2050, with 160,000 eVTOLs in operation – if the technological integration is successful, regulation is formalised and the public accept the concept. Morgan Stanley, while more bullish with a 2050 market ‘base case’ forecast of $9tr (£6.4tr), nevertheless thinks investors should move today but remember to “temper your excitement with patience”.
Ready for vertical take-off? Perhaps it’s better to say that the weather forecast is good and pre-flight checks are well in hand. Mostly, and hopefully, eVTOL is just waiting on the baggage.
Key considerations for eVTOL
Carbon-based and other composites have been vital to eVTOL development. They are 40 per cent lighter than aluminium and five times lighter than steel and have already been used to reduce the weight of commercial airliners. The energy benefits they offer mean that eVTOL operators can keep fees down, moving toward the objective of offering services at comparable or even cheaper prices than traditional taxis.
Lilium has partnered with carbon-fibre specialist Toray for the airframe of its planned five-seater jet. Assembly will be undertaken by Spanish group Aciturri, which also works with Airbus, Boeing and Embraer.
Batteries have been one of the main limits on eVTOLs. Based on the maturation of lithium-ion cells – improving at just 5 per cent a year – that technology has, according to data from Archer Aviation, reached a storage capacity of around 250Wh/kg, making its use feasible in eVTOLs. Abingdon-based battery specialist OXIS Energy has been researching alternative lightweight battery technology based on lithium-sulphur since 2004. This can offer the same capacity at half the weight of Li-ion and OXIS has developed a prototype with 470Wh/kg capacity, expecting to reach 600Wh/kg by 2025.
Low-noise performance will inevitably count heavily towards securing public acceptance for eVTOLs. In its latest data for its Maker certification pathfinder, Archer has claimed an output of 45dB when flying at 2,000ft overhead, less than half that of moderate rainfall – and far below that of the helicopters people may initially associate with eVTOLs.
There are four eVTOL configurations and each uses distributed electric propulsion. The most common are propeller-based; multiple motors are fixed in the circular ‘Multicopter’ array. In the ‘Lift + Cruise’ configuration, motors on fixed wings provide lift and a rear motor propels the aircraft forward. In the ‘Tilt Rotor’ configuration, all or some of the on-wing motors can transition from vertical to horizonal propulsion. Alternatively, in the ‘Ducted Vector Thrust’, multiple motors provide jet propulsion for take-off and landing.
Apart from lower energy consumption and noise, these configurations have allowed designers to incorporate a great deal of redundancy, with the motors made sufficiently independent so that the aircraft can continue to fly safely should one or more fail.
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