Lilium

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Discussion

RobDickinson

Original Poster:

31,343 posts

253 months

Saturday 22nd April 2017
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EV fan powered 2 seater vtol aircraft..

Looks very interesting

https://lilium.com/

dr_gn

16,140 posts

183 months

Saturday 22nd April 2017
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Sounds legit; what could possibly go wrong?

SeeFive

8,280 posts

232 months

Saturday 22nd April 2017
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Followed by the phrase nobody want to hear on this one...

"Your Uber Has arrived".

Eric Mc

121,784 posts

264 months

Saturday 22nd April 2017
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I'm impressed.


The problem, as with any aircraft that is "in the hover", is that if you lose power "in the hover" there is no alternative but to crash.

Merry

1,360 posts

187 months

Saturday 22nd April 2017
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Is that not somewhat mitigated in this instance by the number of fans and I'm assuming motors giving you built in redundancy?

Also guessing if battery powered it'd have a minimum charge level where it'd just land before running out.

I guess the issue is what happens if it hits something mid air with these. Parachute maybe?

Wobbegong

15,077 posts

168 months

Saturday 22nd April 2017
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Ballistic recovery systems are becoming more common in light aircraft. I'd have thought it could be designed in?


dr_gn

16,140 posts

183 months

Saturday 22nd April 2017
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As with flying cars - can anyone seriously see widespread use of these things within the next 100 years? The regulations alone would probably take decades to write, and even then, what happens the first time one crashes in a city and kills a few people?

London to Paris at 300km/h in that thing? Thanks, but no thanks.

Equus

16,770 posts

100 months

Saturday 22nd April 2017
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Wobbegong said:
Ballistic recovery systems are becoming more common in light aircraft. I'd have thought it could be designed in?
The details do say that it's to be fitted with a whole aircraft parachute.

If you're in the hover, though, chances are you're either landing or taking off and so not at great altitude (you're unlikely to have enough battery to squander that you'll do much hovering at height). The bad news is that a ballistic recovery system wouldn't have time to deploy. The good news is that you might not have far to fall and so might not hit the ground so hard, anyway. And as Merry says, the chance of all 36 motors quitting simultaneously - especially given the reliability of electric motors - is negligible. Just so long as they don't wire them all to the same fuse. wink

It's interesting that they have chosen to use 36 separate electric motors rather than one or two big ones, ducted to rotating nozzles like the Pegasus. I'm reading a book on the development of the Pegasus at the moment, so I'm getting distinct feelings of deja vu, in respect of the multi-jet solutions tried in the 1950's and abandoned because they effectively just multiplied the mechanical losses.

dr_gn said:
The regulations alone would probably take decades to write...
Any worse than writing the regulations for drones, microlights or helicopters?

dr_gn

16,140 posts

183 months

Saturday 22nd April 2017
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Equus said:
Wobbegong said:
Ballistic recovery systems are becoming more common in light aircraft. I'd have thought it could be designed in?
If you're in the hover, chances are you're either landing or taking off and so not at great altitude (you're unlikely to have enough battery to squander that you'll do much hovering at height). The bad news is that a ballistic recovery system wouldn't have time to deploy. The good news is that you might not have far to fall and so might not hit the ground so hard, anyway. And as Merry says, the chance of all 36 motors quitting simultaneously - especially given the reliability of electric motors - is negligible. Just so long as they don't wire them all to the same fuse. wink

It's interesting that they have chosen to use 36 separate electric motors rather than one or two big ones, ducted to rotating nozzles like the Pegasus. I'm reading a book on the development of the Pegasus at the moment, so I'm getting distinct feelings of deja vu, in respect of the multi-jet solutions tried in the 1950's and abandoned because they effectively just multiplied the mechanical inefficiencies.

dr_gn said:
The regulations alone would probably take decades to write...
Any worse than writing the regulations for drones, microlights or helicopters?
Yes - "drones" don't carry people, microlights are few and far between (and don't operate in cities), and neither these nor helicopters are in widespread use as a means for commuting.

Also, you'd suddenly require either a huge number of trained taxi pilots (how much would that cost?), or a fully automated flight and navigation system (which doesn't exist for these things). I just can't see either of these being viable from a cost point of view for widespread use in the near future.

If these are intended as novelty toys for a few enthusiasts (like the Sinclair C5 became), fine, but for them to become mainstream means of transport...would you seriously invest in it?

Re. The height not being an issue for a vertical flight mode engine failure - how far do you think you need to drop before being seriously injured? Chances are maximum power would be required during the transition to horizontal flight, and a failure then would be even worse. And if you happen to be underneath one when it did drop, how would you rate your chances of survival?

Equus

16,770 posts

100 months

Saturday 22nd April 2017
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dr_gn said:
Yes - "drones" don't carry people, microlights are few and far between (and don't operate in cities), and neither these nor helicopters are in widespread use as a means for commuting.
I still don't see the fundamental difference. Helicopters and microlights are relatively common and the rules for operating them well-established. Given the likely cost of the Lillium, I don't think we're going to see traffic jams in the sky any time soon, so it's no big deal.

The website suggests that they intend auto-stabilization software (again, not difficult to conceive in view of current drone technology) that will reject unsafe pilot input and bring the thing down automatically in event of a failure.

Dr. Dionysus Lardner said:
Men might as well project a voyage to the Moon as attempt to employ steam navigation against the stormy North Atlantic Ocean.
he also said:
Rail travel at high speed is not possible because passengers, unable to breathe, would die of asphyxia.
Maybe it's a Dr. thing? wink

... he was right about the first one, mind, though perhaps not in the way he intended!

dr_gn said:
...would you seriously invest in it?
The President of the Michigan Savings Bank to Henry Ford's lawyer Horace Rackham said:
The horse is here to stay, but the automobile is only a novelty—a fad.
Rackham ignored him and invested $5,000 in Ford stock, which he later sold for $12.5 million.

anonymous-user

53 months

Saturday 22nd April 2017
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All that bumpf and not one paragraph on the specific energy density of the batteries required to meet their range / performance targets......


(the Energy density of Kerosine is 46MJ/kg. The absolute best Lithium batteries in not-yet-available, cost-a-fortune, last-just-a-few-cycles, and require-huge-cooling-infrastructure are currently struggling to get over 1MJ/kg. So in simple terms, the 'fuel tank' in this device will have to weigh, roughly, 46 times that of a conventional aircraft.)

dr_gn

16,140 posts

183 months

Saturday 22nd April 2017
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...and "electric jet engines" that "compress air"? What's the point of that if you're not burning fuel? They look nothing more than simple EDF's to me.

Whole thing is just another pipe dream IMO.

Equus

16,770 posts

100 months

Saturday 22nd April 2017
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Max_Torque said:
(the Energy density of Kerosine is 46MJ/kg. The absolute best Lithium batteries in not-yet-available, cost-a-fortune, last-just-a-few-cycles, and require-huge-cooling-infrastructure are currently struggling to get over 1MJ/kg. So in simple terms, the 'fuel tank' in this device will have to weigh, roughly, 46 times that of a conventional aircraft.)
^^^ Now THAT is a valid reason to question its viability, never mind the guff about safety and legislative control.

However, the prototype is flying, and there are good reasons to believe that the necessary advances in battery technology for at least a moderate range capability are on their way.

dr_gn

16,140 posts

183 months

Saturday 22nd April 2017
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You may well dismiss regulation, safety and legislation as guff, but you'll find it'll render the concept invalid just as effectively - if not more - than an imaginary battery.

Equus

16,770 posts

100 months

Saturday 22nd April 2017
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dr_gn said:
You may well dismiss regulation, safety and legislation as guff, but you'll find it'll render the concept invalid just as effectively - if not more - than an imaginary battery.
I disagree.

Fundamentally, an aircraft is an aircraft. We have plenty of helicopters buzzing around the skies. No reason that the certification and control of operation of this type of aircraft should be any different.

dr_gn

16,140 posts

183 months

Saturday 22nd April 2017
quotequote all
Equus said:
dr_gn said:
You may well dismiss regulation, safety and legislation as guff, but you'll find it'll render the concept invalid just as effectively - if not more - than an imaginary battery.
I disagree.

Fundamentally, an aircraft is an aircraft. We have plenty of helicopters buzzing around the skies. No reason that the certification and control of operation of this type of aircraft should be any different.
As I said, helicopters aren't used for mass commuting into and within large cities.

As I also said, the certification and control of this VTOL taxi IF they were used for mass commuting would probably make them unfeasible to opearate in the way they were intended. If on the other hand it becomes a low volume expensive toy for a few rich non-confomists, fair enough.

Equus

16,770 posts

100 months

Saturday 22nd April 2017
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dr_gn said:
As I said, helicopters aren't used for mass commuting into and within large cities.
Neither is the Lillium, and nobody on this forum is suggesting that it will be, initially.

Like cars and conventional aircraft, it will start off as an expensive toy for rich people.

What role, if any, it will develop into is anyone's guess, but as with cars and conventional aircraft, it is sure to happen gradually enough to allow legislation and infrastructure management to keep pace.

FourWheelDrift

88,382 posts

283 months

Saturday 22nd April 2017
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Perfect replacement for the F-35.

dr_gn

16,140 posts

183 months

Saturday 22nd April 2017
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Equus said:
dr_gn said:
As I said, helicopters aren't used for mass commuting into and within large cities.
Neither is the Lillium, and nobody on this forum is suggesting that it will be, initially.

Like cars and conventional aircraft, it will start off as an expensive toy for rich people.

What role, if any, it will develop into is anyone's guess, but as with cars and conventional aircraft, it is sure to happen gradually enough to allow legislation and infrastructure management to keep pace.
Let's re-convene in 2025 and see how far it got.

My guess is by that time it'll have long since gone the way of every other door-to-door type personal flying machine that's been proposed over the last 75 or so years.

Eric Mc

121,784 posts

264 months

Saturday 22nd April 2017
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Equus said:
dr_gn said:
As I said, helicopters aren't used for mass commuting into and within large cities.
Neither is the Lillium, and nobody on this forum is suggesting that it will be, initially.

Like cars and conventional aircraft, it will start off as an expensive toy for rich people.

What role, if any, it will develop into is anyone's guess, but as with cars and conventional aircraft, it is sure to happen gradually enough to allow legislation and infrastructure management to keep pace.
I MAY happen but I doubt it. We've had heavier than air flight for 114 years so it is a mature technology in many ways.
Immediately after WW2 and with the arrival of the helicopter, there were lots of predictions that people would be using small aircraft like motor cars.

That did not happen - although we could have been there at least 50 years ago - especially in countries where flying is very useful - like the US or Australia.

It didn't happen - because of airspace control limitations.

The factor that holds back the "aeroplane in every garage" scenario is not the engineering or the technology of the machine. It's the control of airspace and the technology that governs that

We are still some decades away from where airspace may not need to be controlled and managed. Indeed, I doubt that will ever be.