Lilium vertical take off "jet"

[CTR]

Weight and dimensions please

Originally Posted by mickjoebill

Re the previous posts, sensible questions from Ppruners, which have been put to the company on social media.
They have replied directly, saying the video was edited from more than one flight during their test program and the craft was their full size two seater.

This conversation raises the question of the definition of a "prototype".


Mickjoebill

Mick,

Weight and dimensions please. Then the truth is clear.

[tottigol]

Originally Posted by Ascend Charlie

Then these "Experts" should know that it is far more efficient to accelerate a large amount of air to a low speed, then a small amount of air to a high speed, as well as the noise. Compare the noise and downwash disturbance from a 5-ton helicopter (S-76) in the hover to a Harrier jet.

You mean an 11,000 lbs with 1,100 SHP engines helicopter compared to a 23,000 lbs gross weight aircraft and rated jet engine?
Yeah, the noise may be different.

[Nige321]

Originally Posted by PDR1

... show me the paperwork that would be needed to test fly that under remote piloting (because that's not a trivial thing in an EASA country). Then perhaps I might be less sceptical.

PDR

ESA are involved. I doubt they'd put up with fake videos.
ESA website

[etudiant]

Originally Posted by Nige321

ESA are involved. I doubt they'd put up with fake videos.
ESA website

The ESA web site so helpfully referenced says the concept has been 'validated ...with several scaled prototypes weighing 25 kg'.
It goes on to say that Lilium is now developing its first product, a two seater ultra light...
I think that settles the matter, the video is of one of the prototypes.

[mickjoebill]

A Manager at Lilium HQ have said it was their full scale 2 seater used on the maiden flight video and that the video contains pictures from multiple flights.

You could estimate the craft dimensions from the drone shot with the tech laying underneath.

I'll ask about weight but don't hold your breath
One assumes their plan for world domination has factored in the prospect of evolving battery efficiencies.

Pity they didn't show an unedited flight from takeoff to landing. I've suggested they release an unedited shot from the camera drone that was also airborne.


Mickjoebill

[riff_raff]

Originally Posted by Ascend Charlie

When viewed full-screen, you can see lots of little wobbles in the pitch and yaw plane - a machine of real size and weight (with the subsequent inertia in pitch and roll) could not wobble that fast without some serious stresses.

That's what also caught my eye. It's unfortunate that this start-up felt compelled to release video of a vehicle that clearly does not conform to a production configuration, making a very brief flight that demonstrated some potential stability/control issues.

[CTR]

Thanks Mick

Thanks Mick,

I agree. I won't hold my breath waiting for an aircraft weight.

[Cazalet33]

video of a vehicle that clearly does not conform to a production configuration

Did they claim that it was a production model? I don't think so.

Similarly, the flying bedstead wasn't a production model Harrier.

[mickjoebill]

PDR,
It was, apparently real person with a real job title in marketing who responded to me by email.

So both head of marketing and the co-founder are saying the same thing, that the video was of their full size 2 seater.


Mickjoebill

[Morane]

The flight took place at the Grob Airfield im Mindelheim.

Jo

[SansAnhedral]

Originally Posted by etudiant

The ESA web site so helpfully referenced says the concept has been 'validated ...with several scaled prototypes weighing 25 kg'.
It goes on to say that Lilium is now developing its first product, a two seater ultra light...
I think that settles the matter, the video is of one of the prototypes.

Indeed, the slow speed flight dynamics certainly do indicate that this scaled prototype in the video was 25 kg

[aox]

Some great pictures of it in a British newspaper site about a year ago.

And apparently it will be on sale in 2018

Lilium the world's first electric vertical take-off and landing jet | Daily Mail Online

One thing occurs to me - are those front pods or whatever they are called retractable into the front fuselage sides, as one photo implies?

If so, where are your legs?

[Ascend Charlie]

Yeah, been asked before - when the "pods" retract;

1. Front seaters' legs get crushed;
2. Retractable front wheel assembly gets mangled; and
3. Machine pitches nose down due to the whole structure c.g. being in front of the lifting surface.

[WillyPete]

Originally Posted by Ascend Charlie

Yeah, been asked before - when the "pods" retract;

1. Front seaters' legs get crushed;
2. Retractable front wheel assembly gets mangled; and
3. Machine pitches nose down due to the whole structure c.g. being in front of the lifting surface.

Reminds me of the old Tucker automobile, where he originally planned for front wheel fairings to turn with the wheels and thus have the headlights mounted on them follow the direction of travel, but had to settle for a single headlight in the centre of the bonnet that turned with the steering wheel.

[Slatye]

Originally Posted by SansAnhedral

Indeed, the slow speed flight dynamics certainly do indicate that this scaled prototype in the video was 25 kg

That seems like a reasonable number, which should be quite achievable using the foam (either sheet or carved from a solid block) construction used for millions of RC planes. If you wanted to do a mock-up to show to potential investors, as well as having the ability to do demo flights, that would be a good way to start.

Stick a couple of big-ish (110 - 130mm) electric ducted fans in there (up to around 8kg thrust each at 6kW; 5kg would be more common in the cheaper models) and you should be able to fly that around very nicely - at least when there's no wind.

[mickjoebill]

Originally Posted by SansAnhedral

Indeed, the slow speed flight dynamics certainly do indicate that this scaled prototype in the video was 25 kg

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


Lilium Facebook post from co-founder Patrick Nathen,
"As a founder, I can guarantee on behalf of our amazing investors and all you people out there, we did NOT use CGI or a size scaled model. This is the original size of our previous two-seated concept."

Email from Marketing manager in response to edited video.
"I can confirm that it is the full scale 2-seater.
We are running a test flight program, which means, we are testing it more than once.
We can start and land anywhere, doesn´t have to be exact the same spot, right?
Best, Mareike

Mareike Mutzberg
communications manager"

A remote test flight, apparently not above 100 feet, on "private" property of a fly-by-wire craft, backed by ESA and funded by the founder of Skype is not far fetched. Especially since they were test flying several scale models throughout 2016, videos of which are on u tube.

The thing is just a drone on steroids so remote control is embedded in its DNA.
They plan for it to be autonomous, so there is less to be converted.

Sure, they have shot themselves in the foot by labelling the video a "maiden flight" when it is a glossy compilation of several flights. They seem reluctant to release a continuous unedited shot of a flight which would adress the scepticism that scale models were used.

But it would be very silly of lillium to further mislead the public by making the statements quoted above if they were not true.

Has anyone found a report from a journalist who eye-witnessed the test flights?

Ppruner scepticism up to a point (!) is encouraged, given the radical design and the "forward looking" specification and performance of the craft and the unsatisfactory presentation of the test flights.

Mickjoebill

[Terry Dactil]

In regard to the forward fan array not being retractable without crushing front passengers legs, it's apparently a moot point as the two seater was a concept not necessarily meant to go into production.

It's a bit of a worry that the design team did not notice that small problem right at the start.
I expect the next announcement will be something like
"Yeah, that one was just the concept. The production version will have extra wings... and wheels.... and a big engine... and...err, lots of other stuff"

[mickjoebill]

So in summary what we are seeing is a "scaled prototype" (ie not full size) weighing 25kg (not something with a 200kg payload or a 300 mile range).

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

[ShyTorque]

I wonder how it taxied from the hangar to the runway?

[pettinger93]

Well, either it will fly or it won't. If the above sceptics are right, and nothing beyond a scale model ever flies, we won't hear much more about it. If, on the other hand and in the fullness of time, a full size airworthy aircraft surprises us all with new and astounding technology, the above pruners will all have to eat humble pie. Stranger things have happened and time will tell.