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-   -   Lilium vertical take off "jet" (https://www.pprune.org/rotorheads/578979-lilium-vertical-take-off-jet.html)

Ian Corrigible 26th Apr 2017 11:50

Bell is now also getting into the electric VTOL game: Bell Helicopter, Embraer partner with Uber for electric VTOL taxis (Bell microsite here).


Originally Posted by IFMU
I don't believe the Firefly ever flew.

Correct, though someone did manage to get a battery-powered R44 airborne: Electric Boogaloo part 2: R44 Edition

I/C

SansAnhedral 26th Apr 2017 15:08


Originally Posted by mickjoebill (Post 9752441)
So who is digging a deep hole for themselves, Ppruners or Lilium?

Mickjoebill

So what is the gross weight?

EDMJ 26th Apr 2017 21:52

Have never, ever seen a "real" aircraft prototype flying in Germany without a registration. Which begs the question which class they're going to register it in..

A clever, modern version of "The Emperor's New Clothes".

Anyway, Germans are suckers for these things. Does anyone remember Cargolifter and the amount of money the German state sunk into this....

mickjoebill 26th Apr 2017 23:08


Originally Posted by SansAnhedral (Post 9753084)
So what is the gross weight?

No idea.
Have a guess, a 6 meter wingspan, canopy, electric motors and a battery long enough for one of the test flights, let's say 1 minute.


I wonder how it taxied from the hangar to the runway?
Perhaps the same way a helicopter get to the pad?
Maybe those square things under the bed springs are part of a dolly?


But if it is an air vehicle of significant size and mass (larger than the germa large RC model rules would cover) it would still require the airfield and surrounding area to be notam'd - it should be easy enough to find that notam to add some substance to the claims.
Perhaps someone familiar with dragging Notams from the archive on the Notam website could have a look.
It is a great point that there was no registration. What is the max weight of the large agricultural drone in Europe?


Mickjoebill

Thracian 27th Apr 2017 06:25


Originally Posted by EDMJ (Post 9753374)
Have never, ever seen a "real" aircraft prototype flying in Germany without a registration. Which begs the question which class they're going to register it in..

A clever, modern version of "The Emperor's New Clothes".

Anyway, Germans are suckers for these things. Does anyone remember Cargolifter and the amount of money the German state sunk into this....

Careful ;-)
We germans don´t have the slightest trace of humor ;-)


You have to distinguish between state investments and private ones. Look at the Volocopter guys (building a Heli-like looking electrical 18 rotor multicopter with battery exchange system). They are already doing manned flights with a registered aircraft. Their first manned takeoff was a year ago.
And they´re doing it in Germany.


They just have presented their "2X" model for certification in 2018.


In my humble opinion this will be the first electrical manned aircraft being commercially available.


Of course, it´s not fast, but it´s a beginning


Thracian

XV666 27th Apr 2017 07:39


Originally Posted by ShyTorque (Post 9752635)
I wonder how it taxied from the hangar to the runway?

Really? 1:05 in the video clearly shows a trolley under the machine as it lifts.

aox 27th Apr 2017 08:10


Originally Posted by mickjoebill (Post 9752483)
The airfield in Tussenhausen Germany can be viewed on Google Earth.
According to google earth the taxiway the craft lifted from is around 6.5 meters in width.
Video from a few angles indicates the wingspan of the lilium craft is a similar width to the taxiway.

So an extraordinary achievement if the craft has a wingspan of over 6 meters yet weights only 25kg:)

Mickjoebill

And the pictures in the Daily Mail a year ago really are of it flying amongst some mountains and across some sea quite low.

May 2016: on sale in 2018.

April 2017: first manned flights in 2019

What will next year's update say?

mickjoebill 5th Sep 2017 11:35

$90 million more into coffers
 
Lilium have just raised $90 million to continue development of the lilium jet.
70 staff, recent senior hires from Airbus, Tesla and Gett, co-founders of Twitter and Skype on board.
The team continue to look impressive on paper and social media:), but endurance v payload yet to be well defined, other than one hour endurance at 300kph mentioned in the press release.
https://lilium.com/news/

"The Lilium Jet will be able to travel at up to 300 km per hour for one hour on a single charge - meaning an example 19 km journey from Manhattan to JFK Airport could last as little as five minutes. The jet’s economy and efficiency means flights are predicted to cost less than the same journey in a normal road taxi."

Here is one way to increase payload and range:)
https://www.facebook.com/CivilWork/v...2061358200167/
Mjb

Ascend Charlie 5th Sep 2017 21:59

MJB, did you read the comments on that clip? Astounding how many rockapes thought it was real.

mickjoebill 6th Sep 2017 10:40


Originally Posted by Ascend Charlie (Post 9883356)
MJB, did you read the comments on that clip? Astounding how many rockapes thought it was real.

Potential Lilium investors!

Mjb

Hot and Hi 8th Sep 2017 08:04

More recent 'artist's impressions' on their website https://lilium.com/technology/ now show a big canard (span maybe half of the wingspan of the main wing).

https://lilium.com/images/press/reso...-with-gear.jpg

Ascend Charlie 8th Sep 2017 10:39

OK, so now those canards appear to have lost their swivelling hinges and are now looking very fixed?? Now it is just the engines that swivel to the vertical, but no hinge or actuator is visible - under the wing must be some very strong actuating arms. And the early "design" where the front canard retracted into the nose has been dropped. Obviously they paid attention to the constructive criticism here on Proon.

cattletruck 8th Sep 2017 11:07

I hear it suffers from the dreaded 35 engine approach.

(someone wants their computer cooling fans back).

Rengineer 8th Sep 2017 12:24

Mmmh, let's at least try and guesstimate if this thing has a chance.
To lift off, those fans will need to create more lift than its mass, at least including ground effect. I did a quick calculation based on comparison with known aircraft and found that if it had a mass of say 2 tons and the fans a diameter of 0.6m, depending on propeller efficiency, ground effect, and some more esoteric things, it should require between 700-1200kW total power; let's say 25kW for each of those 36 engines. That doesn't appear totally out of the question for me.
Then, for cruise flight, power would obviously depend on the lift/drag ratio and on speed. For some reasonable assumptions, I find it would need only a fraction of the T/O power (as one would have expected); again depending on assumptions, this could be 5-15% of the take-off power.
Then, with decent batteries, say between 150-300 Wh/kg, there really is a corner of the design space where this vehicle might just potentially be realizable. I'm not saying it will necessarily be successful or reach any of the advertised performance goals, but just from looking at the energy and mass budget, it doesn't seem to be quite out of the question. Obviously that's before we've talked about controllability, failure tolerance, minimum reserves, and all that stuff. We'll see.

riff_raff 9th Sep 2017 03:10


Originally Posted by cattletruck (Post 9885805)
I hear it suffers from the dreaded 35 engine approach.(someone wants their computer cooling fans back).

That's funny. Except it should be "the dreaded 36 motor approach".

Unfortunately, there are quite a few practical issues with this concept that they do not seem to have fully resolved yet.

First, relying solely on differential thrust produced by speed changes of (36?) small diameter fixed pitch rotors to provide satisfactory pitch/roll/yaw control authority, plus the required lift in hover, is a very inefficient approach for VTOL operation.

Second, their claims of "simplicity" and "high redundancy" may be rather optimistic. Having 36 individual motor driven fans does not make the propulsion safer or more reliable if there is some single point in the motor control/power system which if it fails would disable enough motors to cause loss of lift/control of the aircraft. This means several isolated/separate systems for power/control of those 36 motors.

Third, using 36 electric motor-driven fans does not reduce the maintenance requirements or increase reliability versus a conventional commercial helicopter drivetrain. In fact, the most failure prone part of this system will be the high-power motor control electronics. A good helicopter gearbox and turboshaft engine will last >2000 hrs. But an air-cooled aircraft-weight electric motor and high-power control system will likely have an MTBF of a couple hundred hours at best. Consider how worse the situation gets with 36 motors.

mickjoebill 23rd Apr 2018 23:51

Frank Stephenson joins the Lilium team.

Mjb

Ascend Charlie 24th Apr 2018 00:36

If it was Frank Robinson it might gain a little credence.

Aluminium Mallard 24th Apr 2018 05:27


Originally Posted by mickjoebill (Post 10128189)
Frank Stephenson joins the Lilium team.

Mjb

It's just what they need at this stage... a designer to polish the turd a bit more and suck up some more investment. Can't wait for the shiny new video complete with inspiring music.

Rotorbee 25th Apr 2018 08:34

I clicked trough the website a bit more in depth and I am not sure, but somehow I have the impression the team isn't the same as in the beginning. I think to remember on the old site that the founders where entirely non-aviation.
It looks like the new toy has not a lot in common with the first idea, even with the one in the video. That swivelling canard wing is gone. It does not retract. That makes it a fairly normal canard configuration, except for the straight main wing. The arm of the winglets as vertical stabilisation devices seems awfully short. I wonder how effective they are. Anyway, I think reality got them. It looks much more feasible than 3 years ago.
It is hard to judge the extent of the fail safe system approach for the FBW, but let's assume, that they know what they do.
But it does have a parachute now. Either because they want to certify it as some kind of VLA/UL and not in a completely new class as they said on the old page (EASA wasn't amused, probably) or they don't trust the thing as much either. But it swims, too.
While I still don't like the 38 motors configuration (entry to the minimum equipment list, at least 36 must be working), let's see how far they get. My bet is, that the "flap actuator" mechanism will be the biggest problem. Four heavy control "surfaces" (planks with a lot of fans on it) which have to move constantly to keep things at bay. Make it three times redundant, that adds to 12 fast and very light electric motors probably with gear boxes, constantly working back and forth.
I don't see how they want to get yawing under control while hovering. Not with those winglets. I think they make things even worse.
Imagine a gust of side wind close to the ground while hovering. If you "lean" into the wind with these wings, they will suddenly become a nice big sail that wants to push down. I wonder if the fans are speeding up fast enough to counteract this. Or I see one wing suddenly wants to fly and the other not. Now the fans of the not flying wings have to produce lift like hell and yawing, on the other wing they must be virtually stopped, which will disrupt the lift over the wing ... I think they have even worse aerodynamic problems than helicopters.
And we haven't even touched the word flutter with those heavy and wings and vibration producing fans.
The fans compress the air like jet engine, without heating it. I don't get the point of that. Only probably that they need more thrust but the size of the fans is fixed. Is this very efficient as a propulsion system?

The Lilium Jet engines have only one moving part - the central shaft of the rotor holding both the fan in the front and the magnets of the electric motor. This ensures highest reliability in operation and low maintenance costs of the propulsion system. The high redundancy of the system allows large inspection intervals to keep costs much lower than for helicopters or reciprocating engines
Where is the redundancy in a single electric motor. I don't think EASA would let you go flying with even just one motor broken. I think you get even higher maintenance because out of 38, one is bound to fail.

mickjoebill 6th Jun 2018 04:03

Not a lot of new here... a video of a Lillim Presentation made in May by Daniel Wiegand at WORLD.MINDS MOBILITY 2018
Has an apparently unedited video of the 90 second test flight of full scale prototype from 2017.
(curious that they didn't use one of the edited videos that had higher production value and the air to air shot from a drone)

https://lilium.us13.list-manage.com/...7&e=85cc7af9ad

Hopes/claims/design
JFK to Manhattan, same price as a taxi.
60-70% stripped away from the complexity of previous designs.
300 kilometer range in cruise at 300kph
Same energy consumption per kilometre as a electric car but 5x faster
Any component can fail as there is redundancy to every part.
Plus parachute.
ect

Ascend Charlie 6th Jun 2018 06:30

OK, a planeload of 200 international passengers lands at JFK.

40% of them, 80 people, want to go to the same hotel in Manhattan via Lillium "taxis". At 5 pax per load, that is 16 Lilliums. (Lillia?) But there are only pairs of passengers, no single travellers, and they all have a pile of bags.
There doesn't seem to be a cargo compartment, so the bags go in the back seat. That is now 40 Lillia needed.
The landing pads shown in the videos generally depict one central landing spot and 4 parking spots. Say we start with 4 Lillia already on the spot, charged up. 8 pax load their own bags, and hop in. One by one, they stagger into the air and by the magic of their computerised flight plans, they avoid conflicting with the real airplanes landing every 30 seconds at JFK on the alternate runways. They will NOT be blasting off in a straight line to downtown like shown in the videos.

The other 72 people are waiting for another Lillium. They have to come from somewhere, so it takes time - they can't be buzzing around airborne waiting for a landing spot, as that will chew up its battery life, and besides there isn't enough available airspace for 4 more or 36 more to be orbiting the rooftop of the Acme Airlines building. Passengers waiting. Waiting. Stuff it, a real taxi will be faster.
See a problem? The fluffy thinking doesn't allow for any practicalities.

A 300-km range is from fully charged to dead empty. You gotta land with some reserve power, in case some other Lillium is already on your desired spot, and if it flew into JFK to pick you up, it already has a decreased range. Then when you hop out, it doesn't have enough power to go back to its home base, 280km away, so it has to occupy the pad until it is charged up - if there is a facility to charge it.

But this whole industry will keep the CGI people in clover, drawing up more and more Jetson-like creations and asking gullible people to invest in it.

They talk of redundancy - showing that if up to 4 engines on one side stop, the rest can take over. What if they are all at max power already in the hover? A rapid roll takes place, or else it shuts down 4 on the other side, and a descent takes place.

Using too many brain cells on this one, I will have a beer instead and kill them off.

Ascend Charlie 6th Jun 2018 07:24

Got a beer now, but the redundant brain cells are still saying "Horsefeathers!!" to this article.

He claims there is no need for any infrastructure, other than a landing site. (And charging cables/meters?)

Our excitement-prone travellers have packed their bags and carry-ons and purses, and have ordered a Lillium to land on their large front yard, 300km from NY, to take them to JFK for their big Europe trip. It arrives, and then needs 3 hours of charge time from a long extension cord. It's gotta be fully charged to make the distance.

They change their flights to allow for the 3-hour delay, only costs them an extra $300 and a missed connection. They board the Lillium, and fly to JFK. It lands on a LilyPad Somewhere. This place needs to be "Landside", because the baggage hasn't been screened. They find the elevator, which only has one destination - the departures foyer, where they drag their bags into the snake-like queue and wriggle along to the screening points. Along with those who came by regular transport.

There can be no direct entry to the Business Lounge, because there has been no screening for departures.

The arriving passengers also need to go through the full arrival procedure, claim bags, and go out of the secure area at Arrivals, and find the elevator to the top floor LilyPad, to wait for their ride. Which is sitting on the roof, flat battery, while other Lillia circle angrily.

"Any component can fail". What about the parachute?

Terry Dactil 6th Jun 2018 21:47

My *BS* meter maxed out when he started saying it was powered by 'electric jet engines'.
If someone dealing with technology does not know the difference between a motor and an engine, then he is just babbling on with sounds good marketing hype for gullible investors.

BTw. It is an old video of the first model where the front fans were designed to retract into the fuselage and crush the legs of the front passengers.
It appears this feature has been deleted from the latest version.

riff_raff 7th Jun 2018 05:16

Hearing the claims about "redundancy" made in the video reminds me of the classic line from Princess Bride, “You keep using that word, I do not think it means what you think it means.”

Redundancy is not the same thing as fault tolerance of a system. What good are all those "redundant jet engines" if the control surface they're attached to cannot be moved to the position required for a safe controlled (vertical) landing? This is a regulatory requirement. And ballistic parachutes are no help with certification, since they do not ensure the capability for a safe and controlled landing.

Hot and Hi 7th Feb 2019 16:41

Ava CX
 
Looks a bit like a Lilium with an extra wing: Ava CX

mickjoebill 31st Mar 2019 10:44

Another contender/pretender sets up shop... early days

https://www.cnbc.com/video/2019/03/2...h-29-2019.html

mickjoebill 16th May 2019 05:44

Lillium hovered their 5 seat prototype, they say at full weight, a few weeks ago.
36 engines, 12 on the forward canards!
“Triple redundancy” of something...


https://youtu.be/8qotuu8JjQM

Would love to know if in the event of failure of one of the rotation mechanisms, if either the forward or rear wings can independently support the craft in an emergency vertical descent.

Rotorbee 16th May 2019 06:57

It still shows no sign of an experimental registration. I suppose, for EASA/LBA that thing is still a drone or model aircraft, albeit a large one. Though, they can do whatever they want.
Hovering is easy. Transition is difficult. Flying forward too. I doubt that thing has much statical stability.
It would not autorotate, that's for sure, but with those wings, would it glide? The L/D must be horrible and since there is no vertical control surface to speak of, controlling it mechanically would be pretty much impossible, therefore electricity can not be lost. The flight controls are triple redundant. The batteries, too? I just imagined a stall situation. At a certain AoA, the propwash of the front wing will hit the main wing and that would reduce the lift of it significantly. That would mean that the main wing may stall before the front wing, which is a terrible idea.
I think, whenever the proverbial sh... hits one of the 36 fans, bang comes a chute. I am not sure, if the certifying agencies will accept that as the only mean to save you from even the slightest mishap like a dirty windscreen.

Ascend Charlie 16th May 2019 09:38

Wonder why there is no sound of it hovering? And on the concrete pad, no indication of the amount of downwash. These things will stop it from landing in backyards or footy fields.

gg17 13th Jun 2019 15:22

More news from Lilium, which is now planning on basing its tech development team / software engineers in London:At least this round of press releases has stopped talking about 'electric jet engines'.

sandringham1 24th Jun 2020 09:52

Lilium have raised $45m more funding now at a total of $375m see https://www.eenewspower.com/news/ele...covid-downturn and they say they have built the factory ready for production to start with deliveries by 2025, and all this without any evidence of the prototype actually making a wholly wing borne flight or full translation, let alone carry a passenger or the weight of one/four. I admire their confidence and pitch but surely some of these basics should have been nailed by now, how can production be talked about when the proof of concept is still an embryo.

Evil Twin 24th Jun 2020 10:36

How much did Moller raise for that ridiculous aircar thing that never got anywhere?

sandringham1 30th Dec 2020 07:19

Lilium have been very quiet for a while now with no news regarding flight testing although infrastructure and operational plans have appeared but with 600 staff funding must be an enormous issue. This review explains where they are currently. https://evtol.com/features/lilium-re...r-taxi-makers/

Two's in 30th Dec 2020 15:49

I find it fascinating that the proposed Orlando "vertiport" is about 2 miles due south of the threshold to 35R (Lake Nona). Obviously you need convenient connections for arriving international passengers, but there must be obvious airspace limitations for a bunch of unmanned electric UAVs wazzing around next to the extended centerline inside the Class B.

Ascend Charlie 31st Dec 2020 00:53


https://assets.evtol.com/wp-content/...io-150x150.jpg
By Brian Garrett-Glaser

Doubts persist over Lilium’s aircraft design

Lilium is a polarizing company in the eVTOL space, with many outspoken in their dislike of the company’s aircraft design, which employs 36 small electric ducted fans embedded in the wing and forward canard. Mark Moore, for many years the chief evangelist of electric air taxis at Uber Elevate — recently handed off to Joby Aviation — concluded in 2019 that the aircraft’s disc-loading, a measure of power consumption in hover, is far too high.

In January 2020, an article published by German aerospace magazine Aerokurier titled “Hoffnungsträger Oder Hochstapler?” — “Hope Bearer or Imposter?” — an anonymous aerospace engineer concluded it was impossible for the Lilium jet to reach its desired flight time and range. The author calculated that, using current battery technology of 240 watt-hours per kilogram, the jet would only be able to sustain a hover for 67.7 seconds. Allowing only 60 seconds of hover time without reserve — parameters that regulators will almost certainly not approve — the engineer found the jet would be able to fly for less than four minutes, or 11 miles (18 km).

“Either Lilium has found solutions for technical problems no one else knows, or Lilium’s promises can’t be kept,”

In February, Lilium’s first full-scale technology demonstrator was substantially damaged in a fire during ground maintenance activities — an unfortunate but somewhat common occurrence for electric aircraft developers.

“Our second demonstrator was not damaged in the fire and we will continue our flight test campaign with this aircraft once we have fully understood the cause of this incident,” a Lilium spokesperson said at the time. Lilium has made no announcements concerning its root cause analysis of the fire, which may still be ongoing. The company has not flown a demonstrator aircraft since then,
and on and on the veneer goes.

mickjoebill 27th Jan 2021 16:40


Originally Posted by Ascend Charlie (Post 10957473)
and on and on the veneer goes.

$375m sunk so far! Next step is to reimagine the airport, heliport, airfield.....

"​​​Vertiport"

https://lilium.com/newsroom-detail/f...tiport-network

Mjb

sandringham1 13th Feb 2021 06:44

Interesting Forbes analysis of Lilium https://www.forbes.com/sites/jeremyb...spac-air-taxi/

Nige321 13th Feb 2021 09:42

This whole thing reminds me of Elizabeth Holmes and Theranos...
That didn't end well...

mickjoebill 15th Feb 2021 20:09


Originally Posted by sandringham1 (Post 10989725)
Interesting Forbes analysis of Lilium https://www.forbes.com/sites/jeremyb...spac-air-taxi/

The most detailed article so far on Lillium, well worth the read. They really haven't reached any kind of flight related critical milestone.. haven't even transitioned to high speed forward flight.



Mjb

Evil Twin 16th Feb 2021 06:59

Any Lilium investors reading, I have a bridge for sale that you may be interested in.....


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