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Honeywell and DENSO to co-develop and manufacture electric motor for Lilium eVTOL jet; Aernnova to design and build propulsion mounting system

Lilium, developer of an all-electric vertical take-off and landing (eVTOL) jet, is partnering with Honeywell and DENSO, who will co-develop and manufacture the Lilium Jet’s electric motor that will power the Lilium Jet’s engines. Honeywell is already developing the Lilium Jet’s avionics and flight control systems and invested in Lilium in 2021.


A leader in aerospace technologies with more than 100 years of experience, Honeywell also has an alliance with automotive giant DENSO to develop aerospace electric propulsion solutions. Through this collaboration, the Lilium Jet’s e-motor will benefit from Honeywell’s aerospace expertise as well as DENSO’s experience in high-quality volume production.

The Lilium e-motor is a proprietary, high-performance system, on which Lilium, DENSO and Honeywell teams have been working for nearly two years. It is expected to bring exceptional performance and reliability with zero operating emissions typically associated with commercial jet engines.

An air-cooled design offers structural simplicity and ease of maintenance compared with traditional liquid cooling systems, and therefore has the potential to reduce aircraft operating costs significantly.

The e-motor has its rotor and stator in a centrifugal or radial configuration, compared to traditional axial designs. This lowers the component’s weight, manufacturing costs and susceptibility to foreign object damage. It also boasts industry-leading power density, with the first prototypes designed to extract more than 100 kW of power from a system weighing just over 4 kg.

Lilium’s Procurement strategy is to engage with the technology providers with the most suitable expertise. We are already making great progress with Honeywell on its Honeywell Anthem integrated flight deck and flight control computers, and we are delighted to deepen our relationship by also partnering with Honeywell and DENSO on our e-motor. The collaboration with these two powerhouses takes us further along the path to revolutionizing regional air mobility.

—Yves Yemsi, Chief Operating Officer of Lilium

Lilium has also selected Aernnova to collaborate on the Lilium Jet’s propulsion mounting system. Aernnova is one of the largest Tier 1 aerospace suppliers, providing aerostructure for companies such as Airbus, Boeing and Embraer.

A propulsion mounting system or “flap”, the structure that forms the rear part of the wings and front aerofoils, is one of the Lilium Jet’s major components, producing lift by interacting with airflow from the engine. It also houses the propulsion and vectoring systems responsible for vertical and horizontal flight.


Electric jet engines integrated into the wing flaps provide advantages in payload, aerodynamic efficiency and a lower noise profile, while also providing thrust vector control to maneuver the Lilium Jet through every phase of flight. Aernnova and Lilium will work together on the design, manufacture, and supply of the Lilium Jet’s flap structure.

The Lilium Jet’s propulsion mounting system will feature a complex and unique design. The integrated system will serve multiple functions and be modular and scalable. It will utilize lightweight material such as carbon fiber-reinforced epoxy.



This is great if it works, but it is pushing the envelope in loads of ways.
The biggest one is the power required at take off and landing.
Their sophisticated fuel cells ( another challenge ) are great for range, but like all fuel cells, not so great for power.

Joby aviation, backed by Toyota, have a rather less ambitious design, which imposes less load on takeoff.
What I am not so keen on in the design, is that it is designed to recharge, not swap, the batteries on turnaround.
I would not be too enthusiastic in climbing aboard and aircraft, perhaps after a few years of service, with reduced battery capacity.

Perhaps less challenging is this simple air mobility solution, the Velocoptor:

As the pdf shows, it is designed to simply swap batteries on turnaround:


Lilium may work. Probably, better for STOL Jetoptera is working on a similar “distributed propulsion” system and was chosen by the USAF for high speed VTOL.
NASA also worked on distributed propulsion on the X-57 electric airplane.



I like the way that it is able to use generators or batteries, important for early designs.

It is the high disc loading of the Lilium which aroused my, very inexpert, disquiet:

see page 5

it ain't the extra fuel consumption, it is pushing the power peak etc.

Radical advances tend to take longer and cost more than we hope.

But wonderful, of course, when and if it gets flying.


The article you posted is more than about disc loading which is a critical factor in VTOL. However, most of the article discusses “Boundary Layer Control” or BLC which is what is “distributed propulsion” is all about. Also, my point about STOL rather than VTOL.
From studies going back decades BLC is used by all STOL aircraft, e.g. YC-14, C-17, and many others. Multi-rotor VTOL have tried in the past but were limited to mechanical complexity problems. VTOL with more than four rotors is difficult for high speed operation.



I am completely at sea, or perhaps up in the air, about the future propulsion systems having none of the technical chops needed.

However, it is clear that as you say, VTOL is tough indeed.

The significant relaxation that STOL's enable in many of the specs helps a lot.

Of course, the designers then re-challenge themselves by looking for longer range and bigger payloads.

As far as I am aware, the most ambitious plans, at least with the backing of the big boys, for larger low emission air travel are from Airbus:

They seem to fancy hydrogen more than ammonia, which I find somewhat surprising.

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