In this episode of our ‘Sustainability in the Air’ podcast, Daniel Wiegand, Co-Founder & Chief Engineer for Innovation and Future Programmes at Lilium, speaks with SimpliFlying CEO Shashank Nigam. He shares Lilium’s vision to revolutionise regional air mobility by building the world’s first electric vertical take-off and landing (eVTOL) jet.
Starting as a small venture by four students, Lilium has evolved into a prominent aerospace player, focusing on battery-electric aviation as a sustainable solution. Given the promise, air operators from China to the UK, Norway and Switzerland have committed to purchasing the eVTOL jets. The company expects its first eVTOL jet to enter commercial service by the end of 2025.
Please note: This interview was recorded in April 2023. By the time of the episode release, Lilium had completed its fourth and final Design Organization Approval by EASA and had raised additional funding, bringing the total raised this year to $292 million.
Here are the key highlights of the conversation:
How is Lilium different — using jet propulsion in eVTOL (3:08)
Aircraft production, testing and certification (6:55)
What about noise and emissions? (12:23)
Who are the core airline customers for Lilium? (14:11)
Are Lilum’s battery requirements realistic? (17:34)
Infrastructure requirements for the Lilium Jet (22:18)
Partnering with automotive and aerospace players (26:15)
Rapid Fire! (34:11)
Keep reading for a quick overview of the episode.
Why a jet propulsion eVTOL matters
Lilium is taking a unique approach while entering the sustainable aviation fray. Unlike many eVTOL companies that focus on short intra-city commutes as “air taxis”, Lilium is primarily targeting regional aviation. The rationale behind this strategy is the significant time-saving potential of regional flights as opposed to short 20-mile city journeys.
Wiegand emphasises the difference in the efficiency of aeroplanes and helicopters. While helicopters are engineered to excel in hovering, aeroplanes are multiple times more efficient when in forward flight. He also highlights the popularity and efficiency of jet engines in the broader aviation industry, noting that a whopping 95% of all airliners, including business jets, rely on jet engines.
Such engines are favoured due to a plethora of advantages they offer: reduced vibrations leading to a smoother flight experience; decreased noise emissions, which contribute to a more tranquil cabin environment; and enhanced safety metrics, especially concerning blade loss.
Moreover, Wiegand mentions that jet engines also have an aesthetic and technological appeal that propeller aircraft lack.
Ultimately, with the Lilium Jet, they aim to merge the benefits of jet engines with the needs of regional aviation.
However, he admits there’s a trade-off involved. Even though their design offers increased efficiency while cruising, it consumes roughly double the energy while hovering. Wiegand justifies this design choice, stating that in the flights Lilium is targeting, the actual hovering time is limited to 10-20 seconds, minimising the span of this increased energy consumption.
5 ways Lilium is re-inventing regional aviation
1. The new helicopters for premium customers?
Wiegand explains that the Lilium Jet is created with premium customers in mind, offering a spacious and aesthetically pleasing design. This design approach offers benefits in both the premium and commercial sectors:
In the premium sector, it offers ample cabin space, similar to a much larger helicopter.
On the commercial side, the design could be modified to accommodate more passengers, potentially resulting in a more economical ticket price.
Initially, Lilium aims to target the premium market, with routes similar to those of today’s executive helicopters. The Lilium Jet’s applications could include, but are not limited to, airport shuttles and city-to-city connections, Wiegand adds. Additionally, airlines might utilise the aircraft as a premium service, providing seamless connections for airline passengers to their final destinations.
Wiegand, however, clarifies that Lilium is not looking to replace traditional helicopter operations. He explains that helicopters, with their prolonged hover capability, will always have a unique role.
Lilium’s design, on the other hand, is optimised for forward flight with minimal hovering. Their focus is on high-speed passenger transport, aiming to combine business jet comfort and safety with vertical take-off and landing. The design incorporates redundant electric power systems to ensure airliner-level safety and operates solely on battery power.
2. A holistic approach to sustainability
One of the primary benefits of Lilium’s technology is a substantially reduced noise footprint.
Specifically, Wiegand says their eVTOL jet creates a noise level on the ground that is around 20 times quieter than traditional helicopters or business jets. In other words, it is so quiet that the noise emitted is akin to the ambient sound of a lorry or heavy vehicle moving on a city street.
The significantly lower noise level means that these aircraft can operate closer to urban environments without causing sound pollution or disrupting communities.
In addition to the massive noise reduction, Lilium’s technology is entirely emissions-free. They utilise electric power sourced from batteries, ensuring a more environmentally friendly flight.
However, adopting battery power brings its own set of challenges and responsibilities. Recognising this, Lilium is not only focusing on the immediate use of these batteries but is also looking ahead.
They’re actively researching and partnering with experts to explore sustainable battery recycling methods, ensuring that once the battery has outlived its primary purpose in the aircraft, it doesn’t end up as waste. Instead, potential second-life applications for these batteries are also being considered.
Wiegand says that Lilium’s vision extends beyond just one aircraft – ultimately, the company wants to leverage the investments, knowledge, and certifications they’ve garnered in this venture to pave the way for larger aircraft designs in the future that are as sustainable as the present design.
3. Next-generation battery technology and infrastructure
Addressing concerns around Lilium’s battery requirements, Wiegand points out that battery technology has evolved significantly and calls these concerns outdated.
Lilium uses the pouch cell technology from Zenlabs which offers optimal power density as well as energy density to power their aircraft. Independent testing by the leading cell and battery testing lab, Energy Assurance, has confirmed the cell’s capability to support Lilium’s targeted missions of up to 250 km.
Furthermore, the battery technology they’ve chosen showcases an excellent cycle life, exceeding their business expectations. Lilium’s manufacturing partner in Germany, CUSTOMCELLS, has established a production line for these cells, ensuring a high standard of quality and traceability.
The Lilium Jet is designed to work with existing infrastructure, including automotive 800-volt chargers. Charging duration is expected to be approximately 45 minutes (with 300-350 kilowatt chargers) for maximum range missions, with shorter missions requiring less time. In fact, the high power capability of the batteries allows for quicker charging compared to standard cells.
4. Utilising existing infrastructure
From Wiegand’s perspective, while Lilium’s aircraft can operate using existing heliport infrastructure, the need for new vertiports or eVTOL-specific landing facilities hinges on customer demands. Many of Lilium’s initial premium clients, who already have helicopter operations in place, tend to lean towards using what already exists.
However, for airline partners seeking to establish connecting and shuttle services with Lilium’s aircraft, there might be a need to expand or create new infrastructure due to potential capacity issues or suitability concerns. To illustrate this proactive approach, Wiegand highlights Lilium’s collaboration with Ferrovial in Florida, aiming to establish 14 landing sites. Some of these sites are already in the regulatory approval process.
5. Choosing the right aerospace partners
Wiegand stresses balancing the innovative spirit of startups with the meticulous standards of the aerospace industry, a synergy achieved by incorporating seasoned professionals from renowned companies. His approach to scaling up Lilium’s operations combines a deep respect for the aerospace sector’s precision with an appreciation for the efficiency of the automotive industry.
He maintains a clear distinction between the manufacturing dynamics of the two industries. It’s not merely about producing in large quantities – Wiegand emphasises the stringent quality and safety protocols associated with aerospace manufacturing. Moreover, collaborating with seasoned aerospace partners, Weigand believes, offers the opportunity to harness decades of technical expertise — which is very difficult to establish from scratch.
To combine the best of the aerospace sector with the efficiency and large-scale production capabilities of the automotive world, Lilium has partnered with Denso and Honeywell to co-develop and manufacture electric motors for the Lilium Jet.
For Wiegand, the future of Lilium is anchored in such strategic alliances. By integrating the best of both worlds – the rigorous standards of aerospace with the scalability of automotive – he aims to position Lilium at the forefront of innovation in sustainable aviation.
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‘Sustainability in the Air’ is the world’s leading podcast dedicated to sustainable aviation. Through in-depth conversations with top aviation leaders, we break through the clutter and provide a clear roadmap for a net-zero future.
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