23 Mar 2023
European views on how soon and how best electric vertical takeoff and landing (eVTOL) aircraft might create new transportation markets differ — in some cases strongly — with the vision being pushed by urban air mobility (UAM) promoters, such as Uber. At its Uber Elevate Summit in Washington in June, the ride-hailing company promised it was on track to launch air taxi demonstration flights with its partners in the Dallas/Fort Worth area in 2020 and to begin actual commercial service in 2023.
“We are not that bullish at Airbus,” Dr. Joerg Peter Mueller, deputy head of the European aerospace giant’s new Airbus Urban Mobility GmbH, said in September during an interview at the subsidiary’s new offices in downtown Munich. “I had a very ‘engaged’ discussion with Mark Moore from Uber on that,” Mueller added, referring to Uber Elevate’s director of engineering for vehicle systems. “We are perhaps a bit more, uh, let’s say, conscious about the challenges of aerospace and safety and airspace integration. Also, noise, public perception. So, we are taking a bit more pragmatic approach to things.” Uber, Mueller noted, is a mobility company creating “an ecosystem around their asset, which is the platform, the app, and the customer.” At the Uber Elevate Summit, Moore told Graham Warwick of Aviation Week and Space Technology, “We are confident we know how to execute the critical path to 2023.”
Dr. Joerg P. Mueller, Head of Programmes & Strategy, Airbus Urban Mobility (Airbus photo)
Airbus, which is not among Uber’s six announced air vehicle collaborators, sees the potential of eVTOLs emerging more slowly. Mueller suggested it might take at least another five to ten years for eVTOLs certified as safe by regulators to start flying regular air taxi service. So, for the moment, Airbus is executing an “exploratory strategy,” he said.
Airbus has been flight testing two different eVTOL vehicles — CityAirbus, a fairly large aircraft built by Airbus Helicopters, and Vahana, a smaller aircraft built by the company’s A³ innovation outpost in Silicon Valley. CityAirbus is a four-seat aircraft with four large ducts, each holding two 9.2-ft (2.8-m) diameter, fixed-pitch propellers, each with its own 100 kW electric motor, and designed to cruise at 65 kt (120 km/h). Vahana is an unmanned — but sized for a single passenger — tandem tilt wing with eight open propellers, four each on two 20.5-ft (6.25-m) wings, one fore and one aft, and designed to cruise at 103 kt (190 km/h) to a range of 27 nm (50 km). But rather than prototypes of objective vehicles, Mueller said, those are “just technology demonstrators,” built in different sizes and configurations to test electric propulsion.
“We’re exploring … what needs to be done,” Mueller said. “What are the technologies that we need to mature? We invest in those so that we can develop this vehicle. That’s why I don’t have a very clear answer yet to your question, ‘What will the future vehicle look like?’”
As part of Airbus’s exploration of UAM, the company has consolidated management of both CityAirbus and Vahana under Airbus Urban Mobility, which also has teams of experts studying other aspects of UAM — in particular, air traffic management and infrastructure. Beyond that, Airbus subsidiary Voom is now operating air taxi services in San Francisco, Mexico City, and São Paulo, Brazil, using helicopter rides booked on a cellphone app a la Uber; Airbus Urban Mobility has a team of software engineers learning from that. But for the time being, rather than pursuing eVTOL UAM operations, Airbus is really just examining the possibilities.
Mueller said it could take longer for eVTOL operations to be feasible in Europe than in some other parts of the world because any new vehicles will have to be “emission free” to gain European public acceptance. Also, to be economical, eVTOL air taxis will have to fly autonomously. “If you have smaller vehicles with two [to] four passengers and you have to have a pilot with that, that increases the cost very, very significantly,” he said. For the large air taxi fleets many enthusiasts envision, there wouldn’t be enough pilots to meet the demand. “So, for us, it’s a key driver to go for autonomy.”
Most experts agree that truly autonomous flight, in which the aircraft itself recognizes and reacts to changing situations, as opposed to flying a preprogrammed path, will require years more to develop.
Dr. Jochen Kaiser, Head of Visionary Aircraft Concepts, Bauhaus Luftfahrt e.V. (Bauhaus photo)
Bauhaus Luftfahrt’s View
A few miles south of Munich are the offices of Bauhaus Luftfahrt, a nonprofit aerospace research institute supported by the state of Bavaria and funded by Airbus and other industry partners. Dr. Jochen Kaiser, head of visionary aircraft concepts, said he was “more or less skeptical” about the idea of dozens (or hundreds) of eVTOLs buzzing around and within cities — not just soon but ever, at least in Europe. The reasons, Kaiser said, are “culture and acceptance.”
“It might work in some parts of the world,” he said, “But here in Europe, I would say people are skeptical to have lots of flights in the city.” Building up all the infrastructure and vertiports needed within cities also might prove difficult in Europe. “Are people willing to pay for this within cities? Not to mention the noise.”
Bauhaus Luftfahrt, which also gets funding from Munich-area engineering analysis and test company IABG; aircraft equipment supplier Liebherr-Aerospace of Lindenberg, Bavaria; and MTU Aero Engines of Munich, has studied the possibilities of UAM in detail. Kaiser said, “We wanted to see how could such a transport system work and how could it bring a benefit to cities? That was the main idea when we started work on it.”
As of September, his institute had two UAM studies underway for Airbus looking at the transport systems of different cities and a third study for the state of Bavaria examining how UAM might work in Munich and other Bavarian cities, such as Augsburg and Ingolstadt.
“My estimation is yes, we will see such [eVTOL aircraft] systems because they are a good addition to the actual helicopter market, so you get lower cost helicopters,” Kaiser said, referring to urban helicopter services. The technical challenges of building eVTOL aircraft can be met, but “The question is, could this really help to bring a complete new mass transport system into cities?” Here, Kaiser had his doubts.
But that doesn’t mean eVTOLs won’t create a new transportation market. “My personal estimation is, this makes more sense for the rural areas,” he said. “To connect the people with the city [who live] where you don’t have public transport. Because within cities you normally have good transport systems, and you won’t reduce traffic jams by adding a few percent of transport capacity in the air. This will not solve the problems within the cities. But getting from outside the city to the city, or getting to airports — this could be a game changer for some areas.” Even this potential market “still needs time for development,” and to get safe, certified vehicles flying “could take another five or seven years.”
Lilium and Regional Air Mobility
Kaiser’s views are loudly echoed some 20 miles (30 km) westward, at the headquarters of Lilium GmbH, developer of the Lilium Jet, whose design promises speed and whose business plan stands out from the crowd (see [online] “Lilium Goes Its Own Way,” [or in Vertiflite Magazine] pg. 32).
Lilium CEO and cofounder Daniel Wiegand. (Lilium photo)
“Here at Lilium we believe a bit less, probably, than the rest of the market in this fully [autonomous] urban air mobility,” co-founder and Chief Executive Officer Daniel Wiegand said. “City planners will recognize very soon that, similar to the car world, if we had a lot of people doing this [riding in urban air taxis], we have a swarm of bees in the sky. And it’s not even the most efficient thing to do inside a very densely populated area.” Like Kaiser of Bauhaus Luftfahrt, Wiegand thinks the true sweet spot for eVTOLs isn’t UAM but RAM — Regional Air Mobility.
“High-speed rail can connect one center of one large city to another,” Wiegand said, “but the infrastructure cost is way too high to basically connect hundreds of different cities.” eVTOLs with enough speed and range could take the place of high-speed rail and offer a new mode of intercity travel that is faster, cleaner and far cheaper. Lilium promises to start offering such regional air mobility service in 2025, two years later than Uber promises, though Lilium doesn’t specify where.
“We are a bit — maybe a bit — more realistic or conservative here than some of the other players in the market, but we think this is about the time frame it will take,” Wiegand said.
Lilium is advocating an eVTOL “ecosystem” in which every midsize town or city has at least one vertiport and major cities have many. “We think about this way more like bus stations,” Wiegand said. “You have one bus station in a mid-sized city today and you would equally have an eVTOL pad. And if you make a longer trip that is fifty, one hundred, two hundred, three hundred kilometers away, you would probably take an eVTOL in the future and not a car.” This is why “we’re making an aircraft that can carry five people and that can fly — physically fly — 300 km [185 miles].”
The Lilium Jet is currently testing near Munich, Germany. The company predicts a 160 nm (300 km) range. (Lilium photo)
Uber, by contrast, is requiring its eVTOL vehicle-developer partners to design their aircraft to fly just 60 miles (100 km) with enough energy in reserve to fly six more miles (10 km) and land vertically if they have to divert from their original destination. Airbus expects a typical eVTOL UAM mission to cover even less ground than that.
“We have done a lot of analysis and think that the initial market is about [flights from] airports to specific business districts or to interesting points of town,” Mueller said. He estimated that 80% of the world’s airports are within 25 miles (40 km) of the cities they serve. “So, if you can cover 40 km (on batteries), you can already do a one-way trip.”
Others in the eVTOL space are moving more aggressively. Volocopter GmbH of Bruchsal, Germany, which conducted the world’s first manned flight of a bare-bones eVTOL multicopter demonstrator in 2011, has been developing versions of the configuration since and has flown piloted tests in Germany, Dubai, Helsinki and Singapore. Volocopter last summer announced its latest model, the two-seat VoloCity, being developed with funding of $55M arranged by Zhejiang Geely Holding Group Co., Ltd, a Chinese company that owns Volvo, Lotus and a number of other automobile brands (as well as flying car company, Terrafugia).
The VoloCity, slated to become the company’s first commercially certified aircraft, is designed to fly missions of 22 miles (35 km) at 68 mph (100 km/h). “We expect to offer the first commercial routes in the next 2-4 years, so a bit earlier than Uber’s timeline,” Volocopter spokesperson Helena Treeck said in an email exchange. It’s too early to say where those flights will be made just yet, but Volocopter is in talks “with several cities across the world, Singapore and Dubai just being two of them.” The first flights will include a pilot, she said, partly to “accelerate the certification process,” and the first routes will likely be to and from the airport to the center city. “We expect to be able to stay 30 minutes in the air but offer shorter routes that will take up to approximately 15/20 mins.”
Most aggressive of all among eVTOL developers is Chinese company EHang, which demonstrated passenger flights in April 2019 with its model 216 in Vienna and has partnered with Chinese-owned FACC in Austria. The 216 is a multicopter with 16 open, coaxial propellers held on eight spars radiating from its small, two seat cabin. EHang announced in August that the government of Guangzhou had agreed to let the company begin UAM operations including “autonomous” flights, monitored by a command and control center, to test flight routes and vertiports. EHang also has sold a couple of dozen EHang 216s to various international customers, according to a company news release. On Oct. 31, EHang filed with the U.S. Securities and Exchange Commission to sell an estimated $100M in depository shares in an initial public offering. (The IPO also listed a single-seat production model as the EHang 116.)
“The startups have different approaches than we have,” observed Airbus’s Mueller. “It’s amazing because it drives the industry and it shows what’s reasonable.” If their experiments and demonstrations turn out well, “That’s actually great to move the industry forward.”
But given the importance to the future of UAM of public acceptance, both Mueller and Bauhaus Luftfahrt’s Kaiser said they hoped those moving to offer eVTOL service quickly were paying sufficient attention to safety. If being aggressive should lead to a crash or mishap that injured or killed someone, “you could have the same situation as it was with the helicopter transport system in the ‘70s,” Kaiser said, when a helicopter mishap on the roof of the Pan Am building in Manhattan killed five people, bringing an end to that era’s version of UAM — helicopter commuting that included rooftop landings. “The market was gone,” Kaiser said.
Mueller agreed. “That’s the danger,” he said. “If [early eVTOL providers] put the whole reputation of the industry in danger, in jeopardy, they have lost all of us.” The Lilium Jet is currently testing near Munich, Germany. The company predicts a 160 nm (300 km) range. (Lilium photo)