Dobrev's Journal #1: The Lilium Jet. Redefining personal transportation.
This has been long time coming. For the better part of a year, I have thought about starting work on a series of articles, showcasing the innovative companies and products, which manage to captivate my imagination, and give me a glimpse into the world of tomorrow, in my otherwise distracted and very lengthy web prowling sessions. A fascinating vehicle I recently came across, gave me the final push needed to act upon this idea, so without further ado, let's get this show rolling.
So, what is it?
On the first edition of Dobrev's Journal, I would like to present to you the Lilium Jet. A child of Gilching, Germany based manufacturer Lilium Aviation, it is a lightweight 2-seater, personal VTOL aircraft, with an ace up its sleeve- an all electric propulsion system. Let us pause for a second here. I'll admit the following took me a minute to realise, because it's not immediately apparent. The Lilium Jet isn't really a jet, on behalf of a jet engine's inherent property of being, above all else, driven by the process of internal combustion. However with that said, I fully understand the appeal from a marketing stand point to use the jet moniker.
How does it work?
A total of 36 tiltable ducted fans (12-blade impellers), producing 320 kilowatts (435 hp) of power, will provide the Lilium with vertical takeoff and landing capabilities, as well as an average cruise speed of 275 km/h (148 kt), at a projected range of 300 km (185 mi). All numbers which if achieved alongside relative ease of use and enhanced passenger safety, could turn this tiny plane into a viable substitute for small helicopters and traditional fixed-wing aircraft.
Another indicator to that possibility is the aircraft's fault-tolerant design, starting with the construction of the propulsion system, where instead of utilizing one or two big powerful fans, the task of providing thrust is distributed between the aforementioned 36 units. Twelve along each wing's trailing edge, and six on each of the two retractable engine pods near the nose. This set up will allow for the continuation of powered flight even after multiple engine failures, within reason of course. Keeping in tune with the fault-tolerance theme, the avionics computer is triple-redundant, and it is said there will be 12 separate battery backs. And on the off chance that all of these safety measures fail, the craft will be fitted with a whole-plane parachute, better known in the aviation industry as a ballistic recovery system (BRS). A tried and tested technology, which has already saved the lives of not one or two light-aircraft pilots.
An additional layer of safety will be provided by a semi-automated control input system. In simpler words, during flight, the control system will reject pilot input which is deemed dangerous, but it will still grant the person full control within safe flight parameters. Initial models will fly with this hybrid system, whilst in the long term, fully autonomous models will be added to the line up.
Does current technology support the design?
I think it does, but I have my questions. I say questions and not doubts, because having doubts would imply possessing an extensive knowledge of the subject in question. Back on track. Electric vehicles of any kind have always faced one specific limitation, and that is operational range. In this regard, cars have the advantage of being able to accommodate large amounts of small battery cells, connected together to form very heavy battery packs, the weight of which is, to a differing extent, offset by the removal of internal combustion engines and their accompanying transmissions. A case in point can be the 85kWh battery pack of a Tesla Model S, which weighs 545 kilograms. Fifty-five kilograms less than the maximum takeoff weight (MTOW) of the Lilium Jet. The problem here lies in currently available lithium ion batteries and their energy density, or the amount of power which can be stored in a given unit of volume of said batteries' storage medium. While I may not be privy to the type of energy delivery system the company has selected, I do know of a possible solution. Semi-solid lithium. A revolutionary technology which vastly increases energy density and reduces production costs for li-ion batteries. In fact the company behind this technology is already sending out samples for commercial testing and evaluation, but I will go into more detail about this in my next article.
Does it exist?
Yes. In the photograph displayed below, taken on November 29th 2016, you can see a full scale prototype at the company's workshop. Flight tests are set to begin in early 2017.
What is the end goal of this project?
Lilium's co-founders certainly don't lack enthusiasm in that regard. The company manifesto states their desire to revolutionise the idea of personal transportation, by removing traditional borders limiting movement, like long trips, distant airports and heavy traffic, thus allowing the end user to work where it is convenient, and live where they desire, in the process eliminating the trend of ever-increasing rent prices. Their business model is an integral part of that process. Upon beginning commercial production, the startup wishes to aim somewhat away from direct end-user sales, instead focusing more on middle ground companies willing to set up ride-sharing services. With the ever-increasing autonomy of vehicles, aeronautic control authorities are already looking into developing the legal framework associated with such services. The future looks bright.
As previously mentioned, my next article in this series will be on semi-solid ion. I can not promise a release date, as I have barely scratched the surface of the subject. You may have noticed that I am not the most knowledgeable when it comes to chemistry, engineering or article writing for that matter, so I will be learning as I go. My end goal being that you the readers, learn with me. Criticism and corrections are more than welcome.
Disclaimer: All images used in the making of this article are the intellectual property of Lilium GmbH.