The Lilium eVTOL is one of the biggest names in the industry. Its design isn’t too revolutionary compared to some eVTOL, but this is part of why it works so well.
To understand why the Lilium eVTOL has so much potential, let’s take a look at the company’s history and the aircraft’s design.
The History of Lilium
The company behind the Lilium eVTOL is, unsurprisingly, called Lilium. It’s a German company that was founded in 2015 by 4 aerospace engineers. Their goal has always been to create an electric, zero-emission aircraft capable of carrying passengers and/or cargo.
One of the founders, Daniel Wiegand, came up with the idea of an electric vertical take off and landing aircraft in 2013. He then went on to found Lilium in 2015 before the company came up with 4 small-scale prototypes.
Between 2015 and 2017, the company worked on its first full-scale prototype, the Eagle. It was a 2-seater eVTOL that completed several test flights in 2017. After that, the company switched to a 5-seat version.
This 5-seat Lilium eVTOL was first flown in 2019, completely untethered and unmanned. It made use of 36 electric propellers and was able to fly both horizontally and vertically.
In February 2020, this prototype was unfortunately destroyed in a fire. However, an unfinished model was undamaged, so Lilium continued to use that for its future tests. Later, Lilium abandoned this model in favor of a 7-seat version, which is what it’s currently working on.
The company plans to commercially roll out its Lilium eVTOL by 2024. It’ll serve as a passenger jet for medium-range flights or logistics. We’ll cover this in more detail below.
You can check out this video from Lilium for a visual run-through of its eVTOL’s evolution.
The Lilium Jet
The official name of the Lilium eVTOL is the Lilium Jet. It’s a fixed-wing aircraft that doesn’t look too dissimilar to a normal airplane. This is because, unlike urban eVTOLs, it doesn’t need to fold up to fit into small spaces.
Let’s take a look at some of its design features to understand how it works.
The Lilium eVTOL has 4 fixed wings: 2 at the front and 2 at the back. Fixed wings help it maintain lift during its cruise stage, just as with any aircraft. Because it’s designed for longer journeys, it’ll spend the majority of its time cruising rather than hovering.
We’ve explained the difference between urban and long-range eVTOLs in more detail elsewhere, so check that post out for more information.
The Lilium Jet has 36 ducted propellers to generate lift. There are 6 on each front wing and 12 on each back wing. The propellers sit in a line on the back of the wing flap, and this rotates 90 degrees between horizontal and vertical flight.
One of the most important features of these propellers is the ducting. Ducted propellers have more efficient airflow, as “waste air” – known as swirl losses – is contained rather than lost. You can check out this graphic from Lilium for a clearer illustration.
Another important feature is the reduction in noise. The ducts prevent tip vortices, which create propeller noise, and they’re lined with acoustic material. This helps dampen propeller vibrations before they can become sound waves.
Finally, the shape of the duct means any noise that is produced comes out the front of the engine. It’s then basically “chewed up” by the engine, reducing its overall perceived noise level.
The Lilium eVTOL will come in 5-seat and 7-seat versions, known as club and passenger configurations, respectively. Unlike some other eVTOLs, the Lilium Jet will be piloted. As such, it’ll either have 4 or 6 passenger seats.
However, it’ll only need a sport pilot’s license, which is one of the easiest to obtain. Lilium is installing something called the Flight Envelope Protection System to keep pilots safe. In short, it’ll prevent the pilot from doing anything too dangerous that’s outside of the eVTOL’s normal flight procedure.
How could we discuss an electric aircraft without thinking about the battery? When talking about batteries, we use a term called energy density. In short, it’s the amount of energy (in watts) that a battery stores by weight.
For something like a long-range eVTOL, the battery needs to have a high energy density. This is because it needs to provide enough power for the eVTOL’s flight without adding too much weight. At a certain point, heavier batteries massively reduce efficiency.
The company designed its own battery for the Lilium eVTOL. It has an energy density of 300wH/kg. It means that every kilogram of battery supplies 300 watt-hours of power. As such, it can fly around 155 miles on a single charge.
The Future of the Lilium eVTOL
The Lilium Jet has undergone some of the most extensive testing to date in the industry. As such, it’s one of the companies that’ll likely launch on time in 2024. In fact, the company already has 14 vertiports planned across Florida.
So, what’ll be the purpose of the Lilium eVTOL? Well, unlike some other designs, it’ll fill a mid-range flight niche. Think of journeys such as taking commuters to the airport or as a taxi service to a business conference. While it’ll technically be able to fly around cities, this isn’t what it’s designed for.
One major advantage of the aircraft’s design is that it’ll be much easier to certify. Urban eVTOLs have much greater barriers to cross because of their design and proposed environment.
The Lilium eVTOL, however, is “just” an electric aeroplane. The fact that it looks and functions very similar to a light passenger aircraft means it should be much easier to obtain approval for commercial rollout.
Final Thoughts on the Lilium eVTOL
The Lilium eVTOL is an interesting combination of familiar and unique. It takes everything we know about a normal aeroplane and converts it into a fully electric, vertical take-off version.
This works in its favor, though, as passengers will probably be more willing to fly in a piloted plane than a fully autonomous urban helicopter.