Lilium aviation electric VTOL jet.

[muttbutt]

6 May 2016

A start-up company hosted in an ESA business incubator is developing the world’s first vertical takeoff and landing aircraft for personal use. The electric two-seater will open the door to a new class of simpler, quieter and environmentally friendly planes available from 2018.

“Our goal is to develop an aircraft for use in everyday life,” explains Daniel Wiegand, CEO and one of the company’s four founders.

“We are going for a plane that can take off and land vertically and does not need the complex and expensive infrastructure of an airport.

“To reduce noise and pollution, we are using electric engines so it can also be used close to urban areas.”
Lilium airplane

Founded in February 2015 by four engineers and doctoral students from the Technical University of Munich in Germany, Lilium has already proved the concept with several scale, 25 kg prototypes and is now developing its first ultralight vertical takeoff and landing aircraft.

Simpler and easier air transportation

Today, general public aviation offers fixed-wing aircraft and helicopters. Conventional aircraft are efficient, fast and available in many sizes but require airports often 20–50 km from city centres because of their space-hungry runways and the high noise levels.

Airports are expensive bottlenecks for transportation. This is especially so for short-haul flights, where travel time to and from airports can easily double the duration of a trip. This is not a problem for helicopters, which can take off almost anywhere and are therefore often used for short shuttle flights and special applications.

However, helicopters are very noisy and difficult to fly – which requires expensive licences. They also have no backup in case of rotor failure, making them expensive to build and maintain.
Access the video

The Lilium vehicle combines the benefits of helicopters and fixed-wing aircraft while avoiding their drawbacks. While initially restricted to airfields, the goal is for it to take off vertically from almost anywhere – even from back gardens – it needs only an open flat area of about 15x15 m.

Although taking off and landing like a helicopter, by swivelling its engines it also functions as a very efficient aircraft that can travel at up to 400 km/h.

Entirely electric, the plane is much quieter during takeoff than helicopters thanks to its ducted fan engines. Its batteries, engines and controllers are redundant, making it a much safer design than conventional helicopters.
Mountain flight

The plane is classed as a Light Sport Aircraft for two occupants, with the pilot’s licence requiring 20 hours’ minimum training – almost like taking a driving licence.

It is intended for recreational flying during daylight, in good weather conditions and in uncongested airspace up to 3 km altitude.

Using computer control for vertical takeoff and landing is essential for a vehicle targeted at the consumer market for personal transportation.

http://www.esa.int/Our_Activities/Space_Engineering_Technology/TTP2/Personal_aircraft_aiming_to_take_off_from_your_home

 

[muttbutt]

Some concept images and scale model work.

The (hopeful) specs of the finished aircraft.

Product details
Take-off and landing Vertically
Steering Easy to fly (Fully computer-assisted control system)
License Sport pilot license (LSA)
Number of passengers 2
Max. take-off weight 600 kg
Payload 200 kg
Cruising velocity 300 km/h / 180 mph
Max. velocity 400 km/h / 250 mph
Range 500 km / 300 mi
Power 320 kW / 435 hp

Their website.
http://lilium-aviation.com/

 

[totoro]

Those specs seem like wishful thinking. Even if actual specs are just half of that - it'd make for the best effort in "flying car" territory to date.

150 km/h cruising speed would be plenty for 99% of users and situations. 250 km range would also be acceptable (though barely) once there's a network of landing pads and charge stations around the country. If the thing can be supercharged within 30 mins (while you have lunch). Of course for a huge network of CAA approved landing pads... well, we might never see that. Maybe when all the vehicles are fully automated and controlled by government monitored system.

For a flying car to make sense it really needs to used for commute. Meaning fairly short distances. 50-100 km to workplace and back. And it needs to be cheap enough to make sense. (so 100.000 dollars is too much already. the aircraft will probably cost way more in its first few incarnations though).

Building something in very small series to address the rich crowd to use this as a novely vehicle for some getaways or occasional roadtrips would be useless for entry into mass market territory.

 

[AeroFranz]

The artist's concept shows very little combined rotor area. It may be okay for a scale model, but it will have very high disk loading at full-scale. Thus it will need tons of power (and battery mass) on takeoff and landing. This doesn't pass my sniff test.

 

[shedofdread]

The artist's concept shows very little combined rotor area. It may be okay for a scale model, but it will have very high disk loading at full-scale. Thus it will need tons of power (and battery mass) on takeoff and landing. This doesn't pass my sniff test.

Exactly!

 

[Grey Havoc]

https://youtu.be/ohig71bwRUE

https://www.nytimes.com/2017/09/05/business/dealbook/lilium-flying-car.html

 

[GTX]

The video on the front of their website looks very interesting. I note though that it is an unnamed test - I wonder if there was ballast included to represent passengers? Their website is now listing specs as:

300Km Range
300 km/hr speed

Looks to have room for 2 - 4 people.

Personally, I hope this is successful.

 

[AeroFranz]

How can i say this without being disrespectful? Their claims are a crock of S#!t.
Ok, that wasn't very respectful. Also, it is a true statement.

There is no way in hell they can close the energy budget for the stated mission range and speed, given the discloading they are using, and the battery specific energy they can get their hands on in the next five years.
Also, the founders are four guys straight out of grad school, AFAIK. I choose to believe they are inexperienced and optimistic, because the alternative is that they're (very) successful scammers.
They changed significant chunks of the configuration several times already. The early one, with the retractable canard, couldn't even balance in flight. That's something you can verify by drawing a free body diagram in 10 seconds.
Also, they call their vehicle a "Jet". A JET. Since when electric ducted fans are jets?
End of rant.

 

[Airplane]

Well, considering the FAA won't grant sport licenses to vtol aircraft and given the the cruise speed exceeds 120kts, it will require a full fledged general aviation PPL. They could placard it at 120kts power setting, but its still vtol so a sport license won't work.

The last time I looked, batteries are very heavy. Makes me wonder if that was not a foam and fiberglass ultra light weight large scale drone.

If this is real, I hope the production model comes with an emergency chute.

A friend of mine just bought a new Tesla. He says its a lot like driving a computer in that every now and then the operating system for the displays , which are also controls will completely lock up. You pull over and restart to get it all working again. I am not willing to trust my life to something so heavily computerized to simply not fall out of the sky.

If autopilot failed in a piper, I would just resume flying the old fashioned way. In this thing, you die.

Also, where do you get it serviced at? There is no infrastructure of mechanics and shops for this technology.

 

[TomS]

Largely in agreement. But to answer this question...

Also, they call their vehicle a "Jet". A JET. Since when electric ducted fans are jets?

Since these guys, I guess.

http://www.fanjetaviation.com

 

[Reaper]

I guess we all agree that their concept doesn't really pass an aircraft design engineer's test. They provide evidence of their progress with hover flight tests, but still have to show the transition, which is the most tricky.

Now the question is: they got now 100$Mio and are on par with zee.aero funding. They probably can get all the engineering talent they want, but can they fix the vehicle with apparently ignoring conceptual aircraft design in the first place?

 

[AeroFranz]

Largely in agreement. But to answer this question...

Also, they call their vehicle a "Jet". A JET. Since when electric ducted fans are jets?

Since these guys, I guess.

http://www.fanjetaviation.com

Ha. Must be a German thing. Which is fine as long as you don't use the term with the rest of the world, which takes it to mean a TOTALLY different thing (JET A burning gas turbine).

Anyway, the hovering model did not carry passengers, and i would be surprised if it had fully representative structures, motors, controllers, which are custom and take time to develop. Not to mention a triplex FCS.
Note: i'm not holding this particular bit against them, it makes sense to do some risk reduction while you're waiting for the long-lead items. But hovering an empty shell RC model is not an indication that you're ready for big time.
All it does is draw attention and $90M worth of funding, which are needed to hire the 70+ engineers that are required to turn this into an actual vehicle. Now the question is whether the fundamental concept that they've chosen can be turned into a practical, safe, profit-generating, vehicle.

 

[GTX]

Also, they call their vehicle a "Jet". A JET. Since when electric ducted fans are jets?

Ha. Must be a German thing. Which is fine as long as you don't use the term with the rest of the world, which takes it to mean a TOTALLY different thing (JET A burning gas turbine).

Definition of "Jet": a rapid stream of liquid or gas forced out of a small opening.

Therefore, even a electrically powered ducted fan system could constitute a "jet". I think their naming is perfectly suitable for what it is intended - a marketing term for the general public.

 

[GTX]

I am not willing to trust my life to something so heavily computerized to simply not fall out of the sky.

If autopilot failed in a piper, I would just resume flying the old fashioned way. In this thing, you die.

Also, where do you get it serviced at? There is no infrastructure of mechanics and shops for this technology.

It will only be a matter of time before we see computer piloted (for want of a better term) aircraft in heavy use. In fact, one could argue that it is already happening with airlines, its just that we still have a human pilot on board to satisfy people's fears. Pilots are a career that will die in the future along with taxi drivers.

As for servicing things such as this, I think it will find the infrastructure will develop as it is needed.

 

[sferrin]

The artist's concept shows very little combined rotor area. It may be okay for a scale model, but it will have very high disk loading at full-scale. Thus it will need tons of power (and battery mass) on takeoff and landing. This doesn't pass my sniff test.

Looks like it would be much higher than the Lightning Strike which itself seems to be pushing at boundaries.

 

[GTX]

The last time I looked, batteries are very heavy.

It depends upon what battery technology is being considered.

 

[LowObservable]

That's harsh, AeroFranz.

Wie sagt man "Moller SkyCar" auf Deutsch?

 

[martinbayer]

That's harsh, AeroFranz.

Wie sagt man "Moller SkyCar" auf Deutsch?

Moller Himmelsauto ;D?

 

[TomcatViP]

Ha. Must be a German thing. Which is fine as long as you don't use the term with the rest of the world, which takes it to mean a TOTALLY different thing (JET A burning gas turbine).

Anyway, the hovering model did not carry passengers, and i would be surprised if it had fully representative structures, motors, controllers, which are custom and take time to develop. Not to mention a triplex FCS.
Note: i'm not holding this particular bit against them, it makes sense to do some risk reduction while you're waiting for the long-lead items. But hovering an empty shell RC model is not an indication that you're ready for big time.
All it does is draw attention and $90M worth of funding, which are needed to hire the 70+ engineers that are required to turn this into an actual vehicle. Now the question is whether the fundamental concept that they've chosen can be turned into a practical, safe, profit-generating, vehicle.

The guy that first flew the flying lawnmower might regret the Startup epoch. Making Millions on an empty shell...

https://youtu.be/FvIXJBrclLY

 

[Zoo Tycoon]

First we had the Dot com bubble burst.

Then the Sub prime morgage collapse.

Coming shortly, to an economy near you, the Electric flying car crash!

There are currently nearly 30 electric flying car projects on the go, with each one hoping the other has solved the battery energy density problem (among other issues)........but no one really has.

The fable of "The Emperor New Clothes" comes to mind (again) and maybe should be a taught at Business School.

 

[Rhinocrates]

It often is:

https://en.wikipedia.org/wiki/Tulip_mania

The real lesson is, if you want to make money in a gold rush, sell shovels.

 

[AeroFranz]

Maybe i'm a curmudgeon, but i don't think a startup can pull this off. Let me rephrase that: an extremely well financed startup that doesn't steal aerospace talent from one of the big companies, and embraces and recreates the processes necessary to design, build, and certify a safe, reliable, and economically viable air vehicle.
It's one thing to make a $400 internet-connected juicer, an entirely different one to make an on-demand mobility vehicle.
The more serious contenders, IMHO, are A^3 Vahana and Zee, lavishly bankrolled, and staffed with traditional aerospace people operating without the shackles of government contracts or miser budgets. Zee had a rough start, but is back on track.
For a somewhat similar situation to the current Air Taxi gold rush, we only have to look at the VLJ craze of the last decade. At some point there were a couple of dozens of would-be players. The vast majority failed, with certification being the valley of death for the few that got that far. And that was for a conventional aircraft, not an autonomous electric vehicle. The exceptions were Embraer (traditional aerospace company), and Eclipse (but that can hardly be said to be a success).

@GTX: i agree, the term "Jet" was used by Lilium for marketing purposes, and if you look exclusively at the definition, it's NOT untrue. However, it is also undeniable that the vast majority of people associate jets with gas turbines, and the distinction will be lost on them. They will think: "it's the same engine that's on a fighter jet. It must be really fast!"
Note: I am firmly convinced there is a circle of hell reserved for marketing people. Most likely the eighth, reserved for fraudsters

Here's my prediction, and we only have to wait, oh, maybe two years for it to be verified at least for the early parts, five for the rest.

- Lilium hires enough engineers to get the design to preliminary design review
- They find out that some important considerations had been left out in their conceptual design, or that some assumptions were too rosy.
- Redesign is needed (mind you this is an easy prophecy since they've already changed the design three or four times, and the hard parts are still ahead).
- First flight is pushed back
- Money is spent. They go through another round of financing.
- Most likely the performance specs are lowered.
- Design activities continue, but there are still unforeseen problems with the tightly coupled aeropropulsion system. With distributed propulsion, the pressure distribution on the entire wing depends on the throttle setting of the ducted fans, airspeed, and angle of attack. The people responsible for the triplex or quadruplex FCS need a detailed aero database, otherwise they can't write the control laws. Either you have to do wind tunnel campaigns, or go the CFD route, running millions of points 24/7 on a cluster (that's what Zee did).
- The success of the startup depends on meeting milestones, otherwise it fizzles. They've set the bar so high, and raised expectations by claiming to have flown a full-scale prototype (the RC empty shell), that it's going to be impossible to keep this up.
- At some point, the founding members are going to leave the venture with their pockets lined with a few million bucks (not bad for a couple of years of work fresh out of grad school).
- The work continues with new suckers owners, with new first flight date
- Lilium disappears from the news
- Eventually they decide to cut their losses because even if they make something work with much reduced performance, they still have the hurdle of certification to traverse

Thus endeth Lilium.

But who knows, maybe ten years from now we'll all be zipping around in Lilium jets, and i will eat crow, forever regretting doubting their wonderful invention.

 

[mrmalaya]

To extend the electric car analogy, I have owned 3 Nissan Leafs over the past 5 years and have had no technical trouble with any of them. Not all electric vehicles are created equal.

 

[sferrin]

To extend the electric car analogy, I have owned 3 Nissan Leafs over the past 5 years and have had no technical trouble with any of them. Not all electric vehicles are created equal.

How many flying cars have you owned?

 

[mrmalaya]

Depends how quickly you corner in a Leaf ;D

 

[sferrin]

Depends how quickly you corner in a Leaf ;D

Or how fast an 18-wheeler blows past you? ;D

 

[Reaper]

The more serious contenders, IMHO, are A^3 Vahana and Zee

...and A^3 got a lot of people from Zee. I would see Joby there, too. I don't know if they are only busy on the Maxwell right now.

 

[AeroFranz]

Yes and no. They are providing the motors for X-57 but supposedly they're hovering their vehicle...what was it, the S4?

 

[Reaper]

and I see Aurora, but I dont know if there is a real interest in joining the field!

 

[ian2345]

Lilium still needs some minor changes. A team that created it need to focus on noise reduction, and it should be more-less ready for the market.
The flying vehicle that can get up to 300 mph.. impressive!

 

[Grey Havoc]

Lilium’s New Course: On Verge Of Going Public, It’s Working On A Bigger Air Taxi. Can It Deliver?

The German unicorn has secretly been developing a larger electric aircraft than the five-seater it's presented publicly -- and it aims to bring it to market in unprecedently rapid fashion. It's the latest big claim from a company some former insiders say is promising more than it can pull off.

www.forbes.com

 

[TomcatViP]

Not to be mean but I am glad they are at last openly talking about investor fraud.

 

[Reaper]

so they really havent demonstrated transition yet.

 

[Zoo Tycoon]

Yes, .....don’t fret, it’ll be fine to fly fare paying pax in 30 months time. All they’ve got to do is chuck another billion at it’ll be tickety-boo.

It seems to me the investment firms are now asking too many questions, so take it to the rich dreamers in the general public. Then the gambling Prince might get his money back.

In one of their recent videos I saw in background of one shot a scheme which was far more Joby. My guess is if this goes mainstream we’ll see some high level departures and they’ll be just another Bell XV-3 knock off developer.

I’m intrigued as to why the person interviewed in the article portrays the main man as some kind of genius;- his early designs show he can’t master the concept of a simple moment balance.

 

[Grey Havoc]

Some posts from the 'VTOL on Demand' thread:

Lilium Jet from Germany:

Lilium Air Mobility - Lilium

Lilium is developing sustainable, high-speed air mobility through its electric vertical take-off and landing aircraft, vertiports and digital service.

lilium.com

VTOL, electric, 300kmh, 300km range ... projected


video of the first flight of a 2seat prototype is available on the website

Any relation between that Lilium Jet and Aurora's DARPA effort? Are they close enough in design to cause a ruckus re. patent infringement? ???

The concepts are pretty close, but Lilium carries the fans on the flaps to point them down, Aurora's tilts the entire wing.
One thing that the lilium video on their website does not show is full wingborne transition, which is tricky. I'm also kind of annoyed they call their ducted fans "Jets".

Sundog:

Yeah, that was the first thing I noticed as well. It sure doesn't look like the Brayton Cycle to me.

It seems to me that uncowled props/rotors in those positions would be a potential hazard, in ground handling terms.

From the video it seems as if the entrance and exit is only planned from the front, requiring some kind of gangway.

indeed, the first iteration of Uber vehicles will operate from 'vertiports', which allows you to take advantage of some ground support equipment. Obviously any door-to-door service, which could theoretically land on unprepared surfaces like someone's backyard, would require a different layout. You'd probably want to put the rotors above reach of passengers.

@mboeller: thanks for posting the presentation!

Maiden flight of Lilium's 5 seater
https://lilium.com/newsroom-detail/lilium-reveals-new-air-taxi-as-it-celebrates-maiden-flight

Maiden flight of Lilium's 5 seater
https://lilium.com/newsroom-detail/lilium-reveals-new-air-taxi-as-it-celebrates-maiden-flight

'Flight' is rather optimistic. 'Hover' would be more appropriate. Still, a cool looking design.

A short BBC report on the Lilium.

VTOLicious:

I was wondering where all the batteries are located to achieve 1 hour of flight time @160kts... and was quite surprised that a rather small hatch for the battery unit can be found in the rear of the vehicle. I would have assumed it is installed beneath the cabin floor.

View attachment 614122

I was wondering where all the batteries are located to achieve 1 hour of flight time @160kts... and was quite surprised that a rather small hatch for the battery unit can be found in the rear of the vehicle. I would have assumed it is installed beneath the cabin floor.

Probably to allow for quicker swaping out by ground crew, even when there are passengers on board.

Installed beneath the cabin does not prevent it to be swappable with passengers on board.
Btw, Tesla's 85kWh batt pack weighs 540kg

Soon avalaible in space grey, with Thunderbolt-3 ports.

VTOLicious:

For spotters near Munich
First lift off took place at Sonderflughafen Oberpfaffenhofen: 48° 4'52.97"N / 11°17'29.90"E

The main issue with these proposals is that they all work in a vacuum; in other words, they're feasible as R&D projects. But the question remains, how do we add them to the National Airspace (NAS)? I'm not trying to be a party pooper, believe me, I love the idea of taking an Uber air taxi to the airport and get there in 15 minutes for an extra $40, but first we most find a solution to the issue of adding non-conventional aircraft to existing air traffic control (ATC). Once we can tackle that, with the same levels of safety as current aircraft, then the Jetson are here!

I suspect the issue will be fudged, at least in most countries.

Thing is, once the thing is fully developed (?) , how will they handle traffic jams … ? Imagine a dozen of these stationary waiting for a parking space at the airport, with passengers anxiously staring at the batteries level , He he he...
Well at least, maybe it will relieve cars traffic...

distributed landing pads.

This is not a point to point service by essence, customer will be transported from one area to another one. Think electrical scooter: you don't know where you'll get one but you reach your destination anyway. This but on a symmetrical pattern. You are not going to take a flight to get to one specific point downtown. You'll make use of the service because you expect to cut drastically your commuting time and for this, your target is not a point but a zone (defined by your final commuting time (think CCIP - it's similar)). Then as the years goes by more pads will be available cutting final time to destination (Cities will even recompose themselves spreading on the vertical - I made an architectural model of that) in parallel with the growth of demand.
So to resume my say, there will be no "waiting time" around a landing location. The landing location will be distributed among several option according to your ETA.

It's just like if you were flying from, let say, Japan to the east coast/US and didn't care much about landing anywhere b/w Florida and Boston. Cost is the incentive and absence of delay as your total time to end-destination the services offered.

The economical model is sane. We will see a major recapitalization of our old cities.

'Flight' is rather optimistic. 'Hover' would be more appropriate. Still, a cool looking design.

Somethgin abut the video disturbed me for a bit until I thought about it: the video spent more time showing the spectators hugging each other than the vehicle itself doing it's thing. It is, I suppose, a small thing, but it's another example of "feelings" being prioritized over actual merit.

“For a successful technology, reality must take precedence over public relations, for Nature cannot be fooled.”

Richard Feynman

The ENRON type “deception in plain sight” continues

Maybe not quite that bad, but caution should certainly be the watchword of the day.

Somethgin abut the video disturbed me for a bit until I thought about it: the video spent more time showing the spectators hugging each other than the vehicle itself doing it's thing. It is, I suppose, a small thing, but it's another example of "feelings" being prioritized over actual merit.

Because they probably only hovered for 10 seconds, i.e., the entirety of what's shown in the video.

That's a big vehicle (heavy, supposedly 4 passengers+ operator), requires lots of power because the discloading is super high. I can't imagine they have more than a 25% battery fraction. If that's the case, the discharge rate (C-rate) of the batteries in hover must be REALLY high. That is a problem, because you get better specific energy at lower C-rates, and most of the battery development is being pushed by the automotive industry, which doesn't need high C-rates.
I've heard from several quarters that the engineering team bases their performance projections on 'future' batteries with crazy specific energy - virtually unobtainium at this point.

The stacked rotors are undeniably more compact, but unfortunately they don't decrease discloading (thus power required to hover) like individual rotors do. That is, what matters is the projected swept area of the rotors as seen from the top.

I thought that stacked rotors would give you roughly 1,5x thrust, while two individual ones give 2x.

@AeroFranz I bet Lilium are using 18650!

Disc loading and invicid drag: I have no idea whre the f*** they went with long ducting and wedged outlets regarding the expected output section flow speed.

Someone has mixed Schnaps drinking and CFD.

AeroFranz:

Reaper said:

AeroFranz said:
The stacked rotors are undeniably more compact, but unfortunately they don't decrease discloading (thus power required to hover) like individual rotors do. That is, what matters is the projected swept area of the rotors as seen from the top.

I thought that stacked rotors would give you roughly 1,5x thrust, while two individual ones give 2x.

The stacked rotors are undeniably more compact, but unfortunately they don't decrease discloading (thus power required to hover) like individual rotors do. That is, what matters is the projected swept area of the rotors as seen from the top.

I thought that stacked rotors would give you roughly 1,5x thrust, while two individual ones give 2x.

In actuator disc theory, the induced power depends solely on disc loading (well, that and density). This has to be divided by an empirical "figure of merit" (FOM) <1.0 (typically 0.6 to 0.8) to get the actual power required, and that's where you see differences based on rotor configuration. For example, a counter-rotating coax rotor might get rid of swirl so could get something like 5% better FOM (YMMV) compared to a single rotor.
What matters in the end, is how much air you are working with for the amount of thrust you want to produce. A closely spaced coax is pushing the same amount of air through two discs, so it doesn't get to count BOTH disc areas for the calculation of discloading. If you hypothetically get the two rotors infinitely apart (in the vertical axis), then they behave like two separate rotors, and you get to count both areas. Obviously for finite spacings between the two cases, you get intermediate results.

Just a SLIGHT correction to my statement about the closely spaced coax pushing the same air through both discs; the flow is actually contracting before and after the top rotor, so the bottom one, assuming it has the same diameter, is also drawing a narrow annulus of "fresh" air from its surroundings to fill the gap. I don't think that increases effective area a ton. Like I said, you really need to push the rotors far apart to see an effect, and for other reasons designers have been pushing for exactly the opposite trend.

The attached picture shows the power requirements of a notional helicopter with different coax rotor spacings. The more you get the rotors close to each other, the more the required power increases. The single rotor has the highest power requirement, but that's because you kept the rotor diameter the same. Normally you'd make it bigger, with much greater area.

View attachment 614383

I have no background in aircraft engineering, so this is perhaps a stupid question, but why all the rotors? (I have the same question for the Lilium). Surely it is a lot simpler to have the lift generated by a single big rotor, as in the PAL-V?

Long story short, the multirotor configuration has the advantage that it is more survivable in the case of motor failure. With n rotors, you end up losing 1/n of the thrust, which you must compensate for with the other functioning rotors.
Then there is the fact that to control a vehicle in hover, you need to generate moments - forces at a distance from the cg. having distributed rotors gives you that by just adjusting motor RPM. Compare to the complexity of, say, a fully articulated helicopter rotor head. there's more, but these are the things that come to mind.

Lufttaxi-Startup Lilium: Zu schön, um wahr zu sein?

Experten zweifeln an den Versprechen des deutschen Lufttaxi-Herstellers Lilium. Die Firma sieht sich zu Unrecht an den Pranger gestellt. Doch die Kritiker legen jetzt nach.

www.spiegel.de

Here we go....

“But the dream could possibly end suddenly: there are increasing doubts as to whether Lilium - a showcase project, celebrated and admired by ministers and Chancellor Angela Merkel, funded by the European Space Agency Esa - is working seriously. The thesis stands in the room that the ambition of the founders is not compatible with the laws of physics.”

Interesting that the original technical report (thesis) has disappeared from every weby location..... seems to be a bit of a legal thing going on ..... but the laws of physics can’t be prosecuted.

Definitely, ESA handle too much money.

ESA’s funding of such a flawed concept is mysterious;- one wonders as to the ethics, because although relatively small, it provided the credibility for the high net worth individuals.

I understand the majority of the investment to date, has come from a chap who’s normally used to dealing the cards.

Does someone have more info on Lilium's battery incident?

https://twitter.com/x/status/1233393399572652033

Found something...
https://evtol.com/news/lilium-evtol-catches-fire/

This raises the issue that wide-scale eVTOL usage* will mean a lot of aircraft maintenance guys (and I still haven't seen anyone address where they're going to find that many licensed aircraft engineers) having to work with large, high-power battery packs, which is a set of risks the industry isn't used to dealing with. I used to sit next to the guy who did site-risk stuff at Rochester, and there was a brief flutter with potentially getting into the electric bus business (I think somewhere else in the BAE empire had an electric bus design and Transport for London were looking into electric buses, which was a potentially huge contract), enough to look into the safety aspects of possibly assembling something locally, and the possible voltages if something shorted were eyewatering.

*And similarly for all-electric and hybrid CTOL designs

This raises the issue that wide-scale eVTOL usage* will mean a lot of aircraft maintenance guys (and I still haven't seen anyone address where they're going to find that many licensed aircraft engineers) having to work with large, high-power battery packs, which is a set of risks the industry isn't used to dealing with. I used to sit next to the guy who did site-risk stuff at Rochester, and there was a brief flutter with potentially getting into the electric bus business (I think somewhere else in the BAE empire had an electric bus design and Transport for London were looking into electric buses, which was a potentially huge contract), enough to look into the safety aspects of possibly assembling something locally, and the possible voltages if something shorted were eyewatering.

*And similarly for all-electric and hybrid CTOL designs

The automotive industry is going to have to deal with similar given the growth of electric cars.

The automotive industry is going to have to deal with similar given the growth of electric cars.

No, not really;- Lillium must deliver a solution with at least one order of magnitude more power, and at one tenth of the mass budget compared to any car.

It’s now generally accepted that very little of the future electric car technology will be of much value in the aviation sector.(Ref Key note address at Warwick Uni future battery technology conference). Electric car development is focused on cheap Cobalt free battery chemistries which are basically heavy.

Furthermore a big problem with very high power density batteries is they’re more akin to high explosive given that all of the chemistry to release the energy is inside the enclosure. With a liquid fuel tank the air volume above the fuel can be managed, I.e maintained fuel rich, or inert blanket, such that they’re inherently safe.

The automotive industry is going to have to deal with similar given the growth of electric cars.

To a degree. But a car just needs to overcome rolling resistance, an electric aircraft needs to overcome gravity. Conventional cars measure fuel efficiency in miles per gallon, conventional aircraft measure it in gallons per mile. Those figures won't change a great deal in switching to electric, so aircraft power packs will need a much greater power storage level (and probably storage density). I suspect the risk levels will be higher with aviation power packs.

Lilium was not the first and most likely will not be the last company suffering a battery pack fire.

Eviations Alice prototype was nearly destroyed in a fire a few weeks ago:

Eviation's Alice Involved in Fire - CAFE Foundation Blog

Time magazine lauded Eviation’s Alice last year, ranking it as one of the 100 Best Inventions of 2019. Alex Fitzpatrick compared its green goodness to the GHG-loaded nature of commercial aviation. “Flying is dirty work—the aviation industry emits nearly a quarter of total...

cafe.foundation

Alice is in the same class of investor deception as Lillum. With Alice I wonder about it being an insurance job or similar exit plan. It’s a real shame that the more realistic electric aeroplane schemes are going to get such a bad name from these Enron types.

No, not really;- Lillium must deliver a solution with at least one order of magnitude more power, and at one tenth of the mass budget compared to any car.

You missed my point. I was referring to the need to train a large number of maintenance people in dealing with electric vehicles (be those aircraft or automotives). There are currently plenty of ones trained for conventionally powered platforms but far less so for electric. It has nothing to do with the power density.

Alice is in the same class of investor deception as Lillum. With Alice I wonder about it being an insurance job or similar exit plan. It’s a real shame that the more realistic electric aeroplane schemes are going to get such a bad name from these Enron types.

Not quite. Having spoken to some of those involved I think it is more of a case whereby you have a start up trying to move quickly on the leading edge and not always appreciating the complexities of what they are doing whilst trying to keep costs down.

Not quite. Having spoken to some of those involved I think it is more of a case whereby you have a start up trying to move quickly on the leading edge and not always appreciating the complexities of what they are doing whilst trying to keep costs down.

I too have spoken to people trying to develop in this sector and they’re appalled at the deliberate investor deception;- the money flows not to those on the leading edge but to the ones that mislead as to where the leading edge actually is.

VTOLicious:

Lilium just raised $240m... Maybe they should use the money to fund research on battery technology that makes their performance predictions feasible
https://www.ft.com/content/9eb5fcfe-6bda-11ea-89df-41bea055720b

Not quite. Having spoken to some of those involved I think it is more of a case whereby you have a start up trying to move quickly on the leading edge and not always appreciating the complexities of what they are doing whilst trying to keep costs down.

I too have spoken to people trying to develop in this sector and they’re appalled at the deliberate investor deception;- the money flows not to those on the leading edge but to the ones that mislead as to where the leading edge actually is.

Would that be the misleading edge?

With no new investor, the original money guys have to either fold or draw another card.

With maybe 200 + million invested to date, and a new global recession just starting up, what would you do?

Apologies, some of the above quoted posts have been mangled by code glitches. I've tried to improvise as best as I can.

 

[TomcatViP]

Lilium begins flight testing in Spain

Lilium begins flight testing at ATLAS Flight Test CenterLilium plans to conduct a full flight test campaign including full transition and high-speed...

www.globenewswire.com

Lilium extends eVTOL type certification timeline to 2025

German eVTOL developer Lilium said it is extending its type certification program for its Lilium Jet to 2025.

evtol.com

 

[alberchico]

https://www.google.com/amp/s/www.suasnews.com/2022/03/lilium-nv-the-losing-horse-in-the-evtol-race/

Amazing that this project keeps moving foward even there there is a mountain of evidence that shows this design just wont work.

 

[steelpillow]

https://www.google.com/amp/s/www.suasnews.com/2022/03/lilium-nv-the-losing-horse-in-the-evtol-race/

Amazing that this project keeps moving foward even there there is a mountain of evidence that shows this design just wont work.

That link threw me up an XML parsing error*
So here is one that works:

Lilium NV – The losing horse in the eVTOL race

Well this is not a good look for AAM, a most excellent report from Iceberg Research (ed) German company Lilium is building an electric vertical take-off and landing aircraft (eVTOL) — the Lilium Je…

www.suasnews.com

* I know what that means if you don't. Invalid markup tag nesting, in this instance. Thanks for nothing, Google.

 

[steelpillow]

Having read it, yes things do look shaky for Lilium. But then they always look shaky for aviation startups.

Certainly eVTOL is a dangerous target to reach for when conventional ePlanes remain impractical curiosities. If nothing else, it makes for a long period of short and unimpressive-looking flight trials using stopgap technology. But there is nothing to stop the Lilium from being flown conventionally, nothing to stop the technology from maturing - given time.

The key interest to onlookers is the distributed propulsion system, a new idea which is creating quite a buzz in the industry. Is it inherently viable, or is it just a bad idea that is doomed to fail? For every expert whose eyes sparkle at the mention, you will find another who sucks their teeth and changes the subject. Lilium have been its poster child.

It is always a shame when the money runs out before an idea can be properly evaluated. Fingers crossed for Lilium.

 

[TomcatViP]

Runs out?!!

They have copiously swallowed billions!!