Lilium vertical take off "jet"

[Ascend Charlie]

This one looks a bit more like it will ... ummm ... take off?

Aurora Unveils New eVTOL Aircraft at Uber Elevate Summit

[IFMU]

Originally Posted by riff_raff

Compare this to a battery-electric 2 seat rotorcraft that was actually built and flown. It was a modified S-300C helicopter which already had a well developed rotor system and lightweight airframe. The electric motor was rated at 141 kW which was the same power produced by the original Lycoming piston engine. The lithium ion battery pack weighed 1100 pounds which was limited by the S-300C max GW capability . This allowed around 15 minutes of flight with a single pilot on board.

I'm sure the engineers that designed the Firefly were competent, and the motor/controls/battery were all based on current technology. So it would be fair to use the Firefly's demonstrated performance as a baseline to evaluate concepts like Lilium.

I don't believe the Firefly ever flew. Sorry for the response to an old post, I'm behind here.

I will say that anything will fly if you get the disk loading low enough. Asking about size and weight are entirely appropriate.

[oggers]

So a year after their claimed date for a manned flight they have managed instead to fly a large drone that looks like the concept but cannot carry out the functions of the concept. Certification in 2018?

Electric drones doing VTOL is decades old news. The concept was for this thing to carry people and also the wings to fold away so it could drive along the highway. This "first test flight" was actually an RC model aircraft that could do neither. Boring.

[Thracian]

Originally Posted by oggers

So a year after their claimed date for a manned flight they have managed instead to fly a large drone that looks like the concept but cannot carry out the functions of the concept. Certification in 2018?

Electric drones doing VTOL is decades old news. The concept was for this thing to carry people and also the wings to fold away so it could drive along the highway. This "first test flight" was actually an RC model aircraft that could do neither. Boring.

According to their new timeline, first manned flights will take place in 2019 now. Well, I do remember the old one you´re referring to ;-)
Additionally, the new pictures don´t show the slightest chance of retractable "wings". Maybe they came across some serious physical issues with CG? On of the founders being an (inactive) glider pilot, I would have expected this encounter a few years earlier ;-)
What remains, is an electrical driven VTOL aircraft.
A five seater Lilium will presumably be bigger (in terms of wing span) than a comparable 5 PAX classical Heli in rotor diameter. I wonder, how they will get their "Lilium Pads" in downtown Manhattan...


But hey, the´ve got their investors, they seem to have some App (or at least some true image manipulation geeks).
Isn´t that all you´ll ever need in modern business?



Thracian

[Nige321]

For those that can be bothered, there's a different video on Liliums Facebook page which shows a couple of different camera angles and some extra detail.

As certain posters seem to be utterly convinced the whole thing is a scam, I'll leave them to find it themselves...

[Ian Corrigible]

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]

Originally Posted by mickjoebill

So who is digging a deep hole for themselves, Ppruners or Lilium?

Mickjoebill

So what is the gross weight?

[EDMJ]

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]

Originally Posted by SansAnhedral

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]

Originally Posted by EDMJ

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]

Originally Posted by ShyTorque

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]

Originally Posted by mickjoebill

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]

$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]

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

[mickjoebill]

Originally Posted by Ascend Charlie

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

Potential Lilium investors!

Mjb

[Hot and Hi]

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).

[Ascend Charlie]

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]

I hear it suffers from the dreaded 35 engine approach.

(someone wants their computer cooling fans back).

[Rengineer]

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]

Originally Posted by cattletruck

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.