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Lilium Goes Big
  • 04 May 2021 11:22 PM
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Lilium Goes Big

By Mike Hirschberg
Vertiflite, May/June 2021

On March 30, Lilium GmbH announced that it was receiving an additional $830M, and revealed the development of its seven-seat Lilium Jet.

Lilium’s concept for six passengers boarding while the aircraft is being charged, based on its Florida vertiport design by Tavistock Development Co. (all images Lilium)

In the timeline of electric vertical takeoff and landing (eVTOL) aircraft developments, Lilium GmbH first came to widespread public attention in April 2017 with the release of a video of the futuristic, prototype, two-seat Lilium Jet flying around outside the Bavarian capital of Munich, at the Special Airport Oberpfaffenhofen, Germany.

As has often been the case among companies in the eVTOL industry, Lilium has tightly managed the release of information about the company and its aircraft programs for a number of years, making it hard to assess the technical progress of its aircraft development program with its bold marketing and performance claims.

Founded in 2015 by Daniel Wiegand, Sebastian Born, Patrick Nathen and Matthias Meiner, Lilium now ranks as the second company in the eVTOL industry to achieve unicorn status — with a market valuation of more than $1B — which created a widening gap between the positive support Lilium was able to attract from the investment community and the critical reports published about the company in aviation press and mainstream media in its home market of Germany.

Lilium lead test pilot Markus Scherdel in a cockpit mockup. Lufthansa Aviation Training will be responsible for training Lilium’s pilots.

The company has been the subject of recurring criticism over the years for pushing seemingly outlandish performance claims without sufficient substantiation (or including sufficient caveats), and for not always being forthcoming with details. As opposed to some companies who were raking up hundreds of flights and saying very little (e.g. Joby Aviation) or flying a lot and talking a lot (e.g. EHang), Lilium was sometimes considered to have a “big mouth” — making wild claims that it seemed unlikely to be able to back up.

In January 2020, when German aviation publication AEROKURIER and then Der Spiegel — Germany’s leading news magazine — published analyses and comments from outside engineers who concluded that, based on the minimal data Lilium had released, that the company’s Lilium Jet couldn’t possibly fulfill CEO Wiegand’s repeated promise that the eVTOL would carry five people 300 km (186 miles) at 300 km/h (186 mph) with reserve power to spare.

A view of the cabin configured for six passenger seats.

Interestingly, the comments made by these outside critics focused on the aerodynamics and physics required to achieve the published performance numbers did not seem to slow the flow of investments appreciably, with Lilium receiving nearly a quarter of a billion dollars just two months later (see “Lilium Draws Searing Publicity, Then Soaring Investment,” Vertiflite, Sept/Oct 2020). In July 2020, Lilium told Vertiflite that “In the last three months, we’ve announced $275M in total [new investment], which brings us up to a combined total of $375M and a valuation of more than $1B” — thus becoming the second eVTOL startup company to be crowned a “unicorn” (after Joby).

Apparently, those who could see behind the veil of secrecy came to a much different conclusion than those watching from the outside.

The cabin configured for cargo. Note the differences in windows.

Still, the public and eVTOL experts scratched their heads regarding the aircraft’s actual performance capabilities. The existing five-seat prototype had barely begun transition testing when it was destroyed on the ground in an electrical fire. Then COVID-19 shut down testing for the second aircraft (though it is finally expected to begin flying again soon). But in November 2020, the company announced plans with Tavistock Development Company to build a vertiport near Orlando, Florida, with a 300-km (186-mile) range; this was followed in January by an agreement with Ferrovial to develop a network of at least 10 vertiports across Florida.

However, on March 30, Lilium made the stunning announcement that it was getting big money to back up its big mouth and build an even bigger eVTOL aircraft — its 7-Seater, which the company noted was the culmination of five years of technology development across four generations of technology demonstrators.

Big Money

Combining with Qell (Nasdaq: QELL), a publicly listed special purpose acquisition company (SPAC), is expected to add an additional $830M to the company’s roughly $380M raised to date. This is based on approximately $380M in cash held in trust and a $450M private investment in public equity (PIPE), including investments by Baillie Gifford, funds and accounts managed by BlackRock, Tencent, Ferrovial, LGT and its direct impact investing arm Lightrock, Palantir, FII Institute and private funds affiliated with PIMCO.

Qell is led by Barry Engle, a former president of General Motors North America, and is “focused on developing next-generation, sustainable mobility.” Upon closing of the transaction, which is expected to be in the second quarter of 2021, the merged company will be called Lilium N.V., and plans to list ordinary shares on the Nasdaq under the ticker symbol LILM. The transaction values the combined company at approximately $3.3B, at the $10.00 per share PIPE price.

Lilium believes its Ducted Electric Vectored Thrust (DEVT) technology provides a breakthrough in aeropropulsion performance.

Engle stated in the Lilium press release that Qell was “thrilled to be partnering with Lilium to together build the leader in regional electric air mobility. Qell set out to find an exceptional and ambitious technology company, with significant growth potential — and in Lilium we have found that. Lilium has unique technology and one of the most accomplished engineering and commercial teams in electric aviation. The 7-Seater Lilium Jet is a game-changer for transportation.”

The combined company is expected to add Engle to the Board, joining current Board members, which includes former Airbus CEO Tom Enders.

“The experienced Qell leadership team is looking forward to working with Lilium. Our board has a collective set of experiences in growing businesses, strengthening operations, expanding globally, raising capital and creating long-term value,” Engle said. “I have spent my career in mobility and been part of the electrification of the automotive industry. The market and societal potential from the electrification of air travel is enormous. I, and the whole team at Qell, are excited for the impact Lilium can have and the part we can play.”

Wiegand said, “We’re incredibly excited to reveal the development of our 7-Seater Lilium Jet and announce the next stage of our growth. This is a validation of all the hard work over the last five years from our talented team and our world-class partners and investors… In Qell, we have found a partner who shares our ambition for sustainable mobility and brings tremendous experience in running mobility and hardware businesses.”

Lilium has conducted extensive testing of its “electric engines” including this DEVT segment for wind tunnel testing.

The proceeds from the SPAC are intended to fund the launch of commercial operations, planned for 2024. This includes the finalization of production facilities in Germany, launch of serial production aircraft and completion of type certification. Lilium said it has put in place a rigorous aerospace program across all certification, design, testing and production phases, with maturity gates at every stage of the aircraft’s development cycle.

Lilium’s 650-personnel team includes over 400 aerospace engineers with “a combined 4,000 years of aerospace experience” and its leadership team were previously responsible for developing and delivering some of the most successful and complex aircraft in aviation history, including the Airbus A320, A350 and A380, Eurofighter Typhoon, Gulfstream G650 and Harrier VTOL jet. The cash injection will facilitate further expansion of the workforce and finding additional partners.

Lilium has already announced that it is partnering with world-class suppliers whose technology and services have been certified in aerospace around the world for decades, such as Toray Industries, providing the carbon composites for the aircraft’s primary structures; Aciturri, manufacturing the fuselage and wing systems; and Lufthansa Aviation Training, training Lilium’s pilots.

To date, Lilium has secured approximately $200M of commitments from infrastructure partners, including Ferrovial and Tavistock Development Company. Up to 14 vertiports are already planned in Florida. Lilium is also in advanced discussions with key infrastructure partners for 10 vertiports to build a network across Europe.


Lilium was the third eVTOL developer with a SPAC in February/ March, and it had been rumored for several weeks (see “SPACtacular Financing: Billions Coming for eVTOL,” Vertiflite, March/April 2021).

On Feb. 10, Archer Aviation and Atlas Crest Investment Corp. (NYSE: ACIC) announced they would merge in a SPAC with $1.1B in gross proceeds, including $500M held in trust and $600M in a PIPE, reaching a valuation of $3.8B.

Reinvent Technology Partners (NYSE: RTP) announced a SPAC with Joby Aviation on Feb. 24, which raised $1.6B for a $6.6B valuation. The fundraise included $690M cash in trust plus an $835M PIPE and a $75M million convertible note, and is expected to fund the company through certification in 2023, build out of its manufacturing facilities and initial operations in 2024.

In addition, helicopter operator Blade UAM landed a $400M SPAC and announced plans on Dec. 15, 2020, to eventually transition to eVTOL aircraft. On Feb. 18, Surf Air Mobility Corp. of Los Angeles announced that it had entered into a definitive agreement to acquire hybrid-electric conventional takeoff and landing (eCTOL) pioneer Ampaire.

Lilium believes its design will readily scale from its 7-Seater to a 16-Seater design, much better than a generic four-passenger open-rotor design.

Small-Time History

Wiegand originally conceived the basic eVTOL jet concept in 2013. There were two small-scale models, Gleiter and Hexa, followed by two larger sub-scale prototypes: the fifth-scale Dragon and halfscale Falcon. The earliest operational concepts had two sets of pivoting, retractable canards, as well as folding wings to fit in a parking space.

Lilium’s third-generation Eagle was a full-scale unmanned demonstrator sized for four seats, which conducted a series of unmanned test flights in April 2017.

Following a relatively abbreviated flight test program, Lilium moved forward with a five-seat model, announcing it in 2018 as its production model, with room for a pilot and four passengers. The five-seater, recently revealed its name as “Phoenix,” has 36 “electric engines” — fans embedded in the flaps of the forward and aft wings — ganged in sets of three fans, each vectoring independently for control in hover, transition and cruise. Two aircraft were built. On May 16, 2019, Lilium announced the first flight of its first untethered, unmanned five-seater, which had taken place on May 4, 2019, after extensive ground testing.

The four-seat Lilium “Eagle” technology demonstrator first flew in April 2017.

A Lilium press release and video in October 2019 showed the aircraft flying in partial wingborne flight, “flying at speeds in excess of 100 km/h” or 62 mph. The February 2020 fire and the COVID-19 lockdown and restrictions, precluded any further work on the second Phoenix demonstrator, but it has been completed and fitted with improvements. Wiegand explained in an interview, “when the fire occurred was when we reassembled the battery pack to resume the second part of the flight test campaign. And then we had the fire, we had the shops closed for 6–8 weeks because of all the cleaning in the buildings. And after that COVID hit and we said, okay, then let’s use the time to upgrade the aircraft.”

However, a Feb. 10, 2021, article on Forbes.com, revealed that the company was working on a seven-seat version of its Lilium Jet, and had aspirations for even larger models. In fact, the article quoted that Alexander Asseily, an early investor in Lilium and now the company’s chief strategy officer, had long abandoned the five-seat design. “We were never going to ship it, we were never going to certify it.” (See also the sidebar, Lilium's Technology Approach Explained)

A Bigger Aircraft

The Lilium “7-Seater Jet” — indicating six passengers and a pilot — has a projected cruise speed of 175 mph (280 km/h) at 10,000 ft (3,000 m) and a range of 155+ miles (250+ km), including reserves. The company also published its dimensions: the wingspan is 45.6 ft (13.9 m) and overall length is 27.9 ft (8.5 m); its five-seater has a wingspan of about 36 ft (11 m).

The five-seat Lilium “Phoenix” demonstrator first flew in May 2019.

The company says its eVTOL aircraft will “revolutionize regional travel, saving people hours not minutes.” Its “regional shuttle service will enable sustainable, high-speed transportation.” The 7-Seater Lilium Jet has market-leading capacity — company founder Wiegand noted that it has 50% more passenger capacity than its leading competitor, the four-passenger Joby air taxi — and is “capable of quiet vertical take-off, allowing Lilium access to more landing sites and the opportunity to build higher network density, avoiding the need for expensive ground infrastructure.”

In an interview with Vertiflite, Wiegand said that Lilium hired its commercial team four years ago, in 2017, and they looked extensively at the different business models, such as air taxi, shuttle flights, etc. After a year of study, the company “decided to fully exploit the ability of our technology to go for a bigger airplane, because we found that a shuttle business model going into a city would give us two big advantages. Firstly, we would get higher time savings. We would get hours of time savings for our customers, not 10, 20 minutes or so. And because of that, it would enable us to bring more passengers on one flight.”

He noted that “this is crucial to get better unit economics and to get the prices down, because it allows us to distribute the cost of the pilot and the landing fees — which are always the same [regardless of number of passengers] — over more passenger tickets.”

Thus, with this 2018 decision to go to a larger aircraft, the five-seat Phoenix became a technology demonstrator before its first flight.

Lilium applied for concurrent type certification for a highcapacity aircraft with the European Union Aviation Safety Agency (EASA) and the US Federal Aviation Administration (FAA) in 2018. Development of the 7-Seater Lilium Jet began in stealth mode following this milestone. In late 2020, the 7-Seater Lilium Jet received CRI-A01 certification basis from EASA. The EASA Special Condition SC-VTOL draft was published in October 2018 and finalized the following July.

Lilium Vertiport rendering

Explaining the process, Wiegand said, “You start with the requirements and the regulators. Then, you talk about your means of compliance with the regulators. Once you have clarity on this, you pursue into the detailed design, you have your preliminary and critical design reviews, and then you’re going to ground tests and flight testing… we are now in the detailed design of the 7-Seater.”

Lilium also noted that its propulsion systems architecture — embedded ducted fans on a wing and canard — are conducive to scaling up to larger capacity designs, while still being able to use the same infrastructure. The company contrasted that with a notional five-seat (four-passenger) tilt-propeller aircraft with a 50-ft (15-m) wingspan. A 16-Seater Lilium Jet, planned for launch in 2028, would have the same wingspan but 3.75 larger passenger capacity.

Big Database

In conjunction with the March 30 announcement, Lilium, for the first time, revealed significant new information on its aeropropulsion approach. The company posted an informally peer-reviewed paper, “Architectural performance assessment of an electric vertical take-off and landing (e-VTOL) aircraft based on a ducted vectored thrust concept,” by founder Patrick Nathen, and reviewed by four European academics. While no data was provided, it laid out the basic approach of the company’s proprietary Ducted Electric Vectored Thrust (DEVT) technology, and why the company believes it has a breakthrough in aeropropulsion performance. The paper indicates an incredible lift-to-drag (L/D) ratio of 18.4, similar to airliners flying at 35,000 ft (10,000 m), and a wing thickness ratio (t/c) of 12% — less than a turboprop and half that of the V-22 Osprey.

The company has conducted extensive ground testing. In Lilium’s investor video, Brian Phillipson, Deputy Chief Technology Officer, noted that the company has “more than 50 different test facilities and the manufacturing facilities required to support them… They allow us to assess structural performance, aerodynamic performance, thrust, propulsion, acoustic and — particularly today, we’re standing in the acoustic wind tunnel, which allows us to assess the acoustic performance of different fan types, different rotor types and to measure the radiated noise, as well as the propulsion efficiency of the motor.” Images showed a full-scale, three-fan segment in a wind tunnel test.

Lilium says it has successfully developed, tested and refined the underlying technology for its eVTOL jets, DEVT, along with key control systems, aircraft and battery architecture. DEVT technology enables Lilium to scale to higher-capacity aircraft and keep noise emissions and ground footprint low, according to the company.

The 7-Seater Lilium Jet will be Lilium’s first aircraft to go into serial production, but it has plans for larger aircraft in the future. Lilium notes that its aircraft will have one-thirtieth the number of parts than a commercial airliner (fewer than 100,000 components vs. about three million) and is designed for ease of manufacturability and scalability.

Lilium plans to apply automotive-style design for manufacturing methods and is designing for fully automated, high-quality production of its engines, actuators and batteries. In its investors briefing, the company highlighted some of these approaches for manufacturability and scaling. This included using very few but highly repetitive components, such as a single type of electric motor, actuator and battery module.

As more data and information come out, it can be analyzed and considered in proving its breakthrough in eVTOL technology.

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