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

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


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...


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

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.....




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.


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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