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Lilium vertical take off "jet"

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Lilium vertical take off "jet"

Old 22nd Apr 2017, 06:50
  #41 (permalink)  
 
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Auto....Auto......wanna see an AUTO
Ah, that would be the dreaded 35 motor approach. Even scarier: two motors out on the same wing, so now down to 34 motors.
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Old 22nd Apr 2017, 06:58
  #42 (permalink)  
 
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QUOTE]Auto....Auto......wanna see an AUTO[/QUOTE]

Er its called ballistic recovery parachute system as fitted to many LSA and larger aircraft. Cirrus C 172 C 150 etc etc.

Been around since the 80's and so far used successfully about 250 times.

Even works when the wings drop off obviously.



You blokes need to get out more often.
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Old 22nd Apr 2017, 07:33
  #43 (permalink)  
 
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Originally Posted by mickjoebill View Post
Do you agree that what was flown was a full size two seater craft, ie of a size that could fit two adults?
Not without something in the video to scale it, no. The dynamics of the lift of were all wrong - something weighing over a ton wouldn't wobble in that way. Also I can't see how ~2000lbs or more of vertical thrust could be achieved with so little noise and so little evident jet-sheeting over the surrounding grass.

It looked and sounded like a model weighing perhaps 10-15kg with an array of standard electric ducted-fan units totalling somewhere in the region of 3-4kW. If it WAS bigger and capable of carrying a couple of hundred kilos of self-installing flight control system then 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.

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Old 22nd Apr 2017, 07:46
  #44 (permalink)  
 
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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.
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Old 22nd Apr 2017, 13:34
  #45 (permalink)  
CTR
 
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Check video at 1:24 for weight indication

Originally Posted by mickjoebill View Post
The point he is making is the production model will be a four seater.
Do you agree that what was flown was a full size two seater craft, ie of a size that could fit two adults?

Mickjoebill
Mick,

If you know or have access to the actual flight vehicle dimensions, just provide them. It may be capable of fitting two passengers, but it appears smaller than he non flying mockup shown earlier in the video.

Regarding the flying aircrafts actual weight. Stop the video at 1:24 and look at the landing gear being used. The three thin curved hoops of either composite or metal could not support a realistic weight of a two passenger aircraft.
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Old 22nd Apr 2017, 13:59
  #46 (permalink)  
 
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And why no wheels? I know it's supposed to be a VTOL aeroplane, but those silly little skids will make it a right pain to move around on the ground (like helis with skids).

Sorry, but no one would get that far with a project with that kind of schoolboy error. It's making the F313 look credible...

PDR
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Old 22nd Apr 2017, 14:29
  #47 (permalink)  
 
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OK, I relooked at the video and a number of questions came to my mind.

1. why did it take off from a taxiway and not from either the runway or a helicopter landing pad?

2. for a first flight why was there no flight data probes? surely you would want to know the environment that the aircraft was flying in?

3. Why did they not list the airport that they took off from, every other first flight video tells you the time and date and where the first flight occurred? Was this flight legal?

4. When it took off it had aGoProo mounted at each wing tip let later on in the video there was one missing, did it loose a GoPro if not was it the second flight that we saw later on in the video?

To be honest there are too many questions and not enough data to make those questions disappear.

Fats
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Old 22nd Apr 2017, 17:26
  #48 (permalink)  
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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

Last edited by mickjoebill; 22nd Apr 2017 at 17:44.
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Old 22nd Apr 2017, 18:45
  #49 (permalink)  
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Weight and dimensions please

Originally Posted by mickjoebill View Post
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.
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Old 22nd Apr 2017, 21:36
  #50 (permalink)  
 
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Originally Posted by Ascend Charlie View Post
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.
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Old 22nd Apr 2017, 23:06
  #51 (permalink)  
 
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Originally Posted by PDR1 View Post
... 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
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Old 23rd Apr 2017, 00:51
  #52 (permalink)  
 
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Originally Posted by Nige321 View Post
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.
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Old 23rd Apr 2017, 02:09
  #53 (permalink)  
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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

Last edited by mickjoebill; 23rd Apr 2017 at 03:41.
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Old 23rd Apr 2017, 05:27
  #54 (permalink)  
 
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Originally Posted by Ascend Charlie View Post
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.
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Old 23rd Apr 2017, 05:34
  #55 (permalink)  
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Thanks Mick

Thanks Mick,

I agree. I won't hold my breath waiting for an aircraft weight.
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Old 23rd Apr 2017, 06:31
  #56 (permalink)  
 
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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.
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Old 23rd Apr 2017, 08:44
  #57 (permalink)  
 
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Originally Posted by mickjoebill View Post
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.
"A Manager" - why no name? Despite the claims that there are tens of people working ion this project you only ever see two or three. Hardly a hive of development activity.

You could estimate the craft dimensions from the drone shot with the tech laying underneath.
Ah, but lying under what? That looks like the mock-up, because no one puts that much fit & finish effort into a flight-test sample. Also if it's a flight-test aircraft where are the datum marks, instrumentation probes etc etc?

One assumes their plan for world domination has factored in the prospect of evolving battery efficiencies.
Current [sorry!] batteries are very efficient - what they need is much higher energy density (especially with respect to mass), not efficiency.

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.
So straight questions:

1. Did this (these?) flight(s) take place in Germany?
2. If so where are the notams for the area concerned that would be needed to operate a remotely piloted vehicle with in AUW in the thousands of pounds region?
3. In Germany an RC model weighing more than (IIRC) 5kg needs various approvals both during construction and to fly. Alternatively a "commercial" remotely piloted vehicle would need certification to something akin to CS22 with a certified design organisation and an operating organisation holding approvals to something akin to the UK's Part 8(a)1. Who holds these approvals, who undertook the certifications or were they flown illegally?

If they could just provide some pretty simple and non-confidential answers they would blow our scepticism out of the water...

PDR
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Old 23rd Apr 2017, 13:04
  #58 (permalink)  
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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
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Old 23rd Apr 2017, 16:25
  #59 (permalink)  
 
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Both Nigel Farrage and Boris Johnson said that we would save paying 350m a week by leaving the EU. Both of them saying the same thing didn't make it any truer.

I'm not accusing anyone of mendacity - I just find it strange that the identified inconsistencies could be easily and simply resolved with almost no effort, but they have chosen not to do so.

Look, I don't know if you've ever tried to integrate "remote piloting systems" into a full-size airframe with a view to legally flying it (even in very restricted tests) European airspace, but I have been involved in it. It's non-trivial. In my view (others may have different views and I may even be wrong) doing the initial tests "unmanned" makes it harder rather than easier, and I simply don't see any of what I would expect to see as the minimum prerequisites in any of the information and claims they've shown to date.

Never mind the picky little detail of how the aerodynamics of that configuration are supposed to work in wing-borne flight.

I'm cutting them some slack - I have assumed that things like the variable nozzle systems needed to allow the same fans to work efficiently for both hover lift and 200mph flight are something they'll add at a later date. But there are just too many details that simply don't add up.

Want one more? Why the deeply-tinted windscreen glass? How's that going to work in marginal viz? Why bother having it on a flight-test specimen...

PDR
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Old 24th Apr 2017, 17:10
  #60 (permalink)  
 
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The flight took place at the Grob Airfield im Mindelheim.

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