Lilium - Point to point small air transport reinvigorated?

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Kyle Boatright

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The difficulties I see with Lilium:
Regulatory, loads of these flying around cities?
Range, getting a good L/D is going to be challenging with all those dinky DFs.
Cost, they are going to need a lot of high energy density batteries. Those just aren't particularly cheap, and won't be without new chemistry. Life is part of that.

Let's say one costs $250k and has an effective range of 30 miles.

A) How many people have that kind of money for a commuter vehicle?

B) The only places you'd want to fly 'em would be from a suburb into a big city. Last time I checked, big cities were short on open space to land, park, and recharge a few hundred Whizbang 3000's on a daily basis.

What I'm trying to say is regulations seem to be one of the lesser obstacles.
 

autoreply

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Ownership of vehicles is an old concept. Something like the Lilium would be rented, leased or be a fractional. You quickly see that model gaining traction instead of car ownership in cities. Same for GA.

What would be a realistic landing footprint. 50 ft flat and 200 ft obstacle free?

A landing platform above a road could do that.
 

Kyle Boatright

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Ownership of vehicles is an old concept. Something like the Lilium would be rented, leased or be a fractional. You quickly see that model gaining traction instead of car ownership in cities. Same for GA.

What would be a realistic landing footprint. 50 ft flat and 200 ft obstacle free?

A landing platform above a road could do that.
I think it is hard to share a vehicle that has a limited range and an extended refueling time. I'm guessing you could make two sorties every rush hour. So, your expensive asset is effectively shared by two individuals - one with a pickup time of 6:30 AM and another who is picked up at 8:30. The evening commute would be similar.

Also, those landing pads would be necessary every mile, spread around the business areas of a city, so the high dollar users wouldn't have to walk very far to their offices. A guy isn't gonna go all-in on point to point transportation if he has to walk very far or catch a taxi...
 

cheapracer

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if he has to walk very far or catch a taxi...
This.

it's the reason people will sit in traffic jams and spend more money than public transport. The comfort of isolation and convenience of arriving at or very close to your destination has yet to be beaten by any other mode of transportation.

Electric cars are going to make it even harder for challengers, more environmentally acceptable, quieter overall, dead silent at a stop (red light etc), more comfortable and much easier to drive in cities than a gasoline car.
 

pictsidhe

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I think it is hard to share a vehicle that has a limited range and an extended refueling time. I'm guessing you could make two sorties every rush hour. So, your expensive asset is effectively shared by two individuals - one with a pickup time of 6:30 AM and another who is picked up at 8:30. The evening commute would be similar.

Also, those landing pads would be necessary every mile, spread around the business areas of a city, so the high dollar users wouldn't have to walk very far to their offices. A guy isn't gonna go all-in on point to point transportation if he has to walk very far or catch a taxi...
Swappable battery packs fixes the first issue, though they will not be cheap.
The site shows a skyscraper helipad type landing pad. It can be gusty and turbulent up there, these things will need very good sideways control. There's going to be a critical point when they have just touched down and are spooling down the fans when they will be susceptible to being blown around.
I managed to watch the video last night. Looks real to me, the little wobbles suggest they haven't quite perfected their control algorithm, or something reacts a bit slow.
The second could be a headache. If the fan lift is being laggy, it'll be hard to fix without variable blading, which would be weight and complexity.
I've actually been looking into a variable stator as ducted fan rpm control, its doable, the speed range isn't great. ~25% without much penalty if you have a fairly coarse pitch fan.
 

BBerson

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With no exposed rotors, it could enter through a garage door on the tenth floor of a skyscraper.
The downwash of the high disc makes ground landings less attractive.
But still needs more power to lift a payload for any usable time. Might work for inter building travel.
 

pictsidhe

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With no exposed rotors, it could enter through a garage door on the tenth floor of a skyscraper.
The downwash of the high disc makes ground landings less attractive.
But still needs more power to lift a payload for any usable time. Might work for inter building travel.
Only if the lift can be changed quickly enough to deal with up/downdrafts and ground effect.
I'd love to see some actual numbers on this thing.
 

vtul

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https://lilium.com/

On the Facebook video I saw this on, they listed a 19 km distance ("the Lilium poad" in Manhattan, NYC to JFK Airport) in 5 minutes' time for $36 up front, then $13 near-term, $6 long term (whatever that means). They compare it to a cab fair of $56-73 distance of 26 km in 55 minutes.
Should be a fun time in the air around Kennedy when Lillium hits it big with such low fares.

Sad to say, though, when the first Manhattan Lillium crash happens, newspaper headlines, youtube videos. FAA investigation, media field day. Stock price plummets.

Public takes cabs to the airport to fly with "professionals."
 

vtul

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Ooops, my bad. I wasn't thinking big.

Eliminate pilots and air traffic controllers and this could work. After all, missions are automated in small quadcopters right now, and autos are getting collision avoidance warning systems. It's not a big step to getting people out of the flying loop. Next decade should see it in.
 

pictsidhe

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Ooops, my bad. I wasn't thinking big.

Eliminate pilots and air traffic controllers and this could work. After all, missions are automated in small quadcopters right now, and autos are getting collision avoidance warning systems. It's not a big step to getting people out of the flying loop. Next decade should see it in.
And piloted aircraft are already having to dodge drones. If your Lilium is pilot-less, a potentially avoidable collision with something the autopilot is unaware of but a pilot could spot won't end well.
 

vtul

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Central computerized control of automated aircraft should do the trick. Punch in your destination and sit back. Piloted UL and GA, and R/C modeling would have to go for public safety reasons. The only uncontrolled collision problem left would then be birds.

Assuming no software bugs. But I suppose those would eventually work themselves out.
 

pictsidhe

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That centralised computer would have to be fail safe. Imagine the chaos if it suddenly stopped doing a proper job on 10,000 air craft with no backup wetware.
 

DangerZone

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Ducted fans experience better performance and efficiency if the inlet flow is unobstructed and laminar. Still, they work reasonable without.

Just have a look at one of the early radio control model ducted fan installations. Especially the Byron F-16 comes to mind. Engine in pusher mode in front of fan, tuned pipe extending forward of fan into intake duct, fan deep in the fuselage, one small forward air inlet and the front wheel forward of the main air inlet, a “cheater” hole.

The Lilum ducted fan inlets look overly refined compared that old RC plane ducted fan inlet. Have a look at a Byron F-16 at RcGroups: https://www.rcgroups.com/forums/showthread.php?971166-Bryon-f16-e-dynamax-the-dynabyro-fan#post11177199

There is the main undercarriage in front of the fan too.
I'm not that familiar with RC aircraft, spent more time consuming research about real size VTOL aircraft. The Americans have conducted excellent tests about half a century ago, and the conclusion was that generally shrouded props and ducted fans are more efficient for low speed high thrust while proppelers are more efficient at high speeds. Finding the right efficiency mid way is really not that easy, but we can always learn from others rather than our own tries and fails. It's much less expensive that way. :)

The idea of a VTOL aircraft which would TO & land like a chopper and fly like an aircraft is a long dream of many. Even movies tend to lead in that direction, remember the aircraft from Oblivion? That was a nice mixture of the Edgley Optica and the DOAK.
[video=youtube;6vbVN1JQGY8]http://www.youtube.com/watch?v=6vbVN1JQGY8[/video]
Brooklands-Aerospace_Optica_Srs_301.jpg

That kind of VTOL homebuilt composite ultralight would be possible with a moderate budget, much less than the inital 11 million euros the Lilium project got. With 11M they should have built at least a dozen of them already. So you see, the issue here is not technology, but the budget and the political ways the money gets distributed. And it seems there are more people here on HBA forum who could build VTOL aircraft that actually COULD fly two persons from one point to another in full safety than in the Lilium team.
 
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Aesquire

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First, the website is broken and doesn't work properly. So their PR/IT staff need to improve.

That has nothing to do with the product.

The powered flaps are a very clever idea.

I've always been a fan of the Ryan VZ-3 and wondered how hard it would be to make a homebuilt version. Say, with 2 80+ hp 2 stroke engines. ( and when one fails in VTOL mode.... hit the Airbag button, no way I'm adding the mass of cross shafting and making it fly )

So multiple small ducted fans on the flap looks intriguing. They should have enough redundancy to make it stay aloft, or descend slower than disintegrate speed, that's cool.

And I won't ever be allowed to fly one. It's a robot. Or the final version will be. Pity, looks like fun.

I'm concerned that robot planes will mean I won't be allowed to fly a light aircraft or hang glider, since all airspace will be under strict control.
I'm also concerned that I won't be allowed to ride my motorcycle in a world of robot cars.

Neither worry is immediate, but both are not paranoid. Commercial air travel dominates where I can fly, and under what restrictions. It was all logical, and made perfect sense, when the decisions were made. "Obviously" passenger & freight operations with hundreds of people and entire planetary economy based on them are more important than a crazy guy who wants to fly a Kitfox down rivers to sight see."Obviously" the concerns of large companies that contribute vast sums of money to politicians are more important than peons that don't.

I can't even argue with all of the reasoning that makes it illegal for me to buzz around with no limitations. I'm not, for the most part, unhappy with the regulations. ( although staying out of the restricted areas flying cross country in a Hang Glider in the crowded North East U.S. can be a challenge with no engine )

I don't think the rules and systems that will make robotic air travel practical are going to be ready for decades. Centralized computer control is Obsolete before it's even close to ready. Cyber terrorism makes centralized systems too dangerous to use.

But there's going to be a LOT of money thrown at that idiocy.
 

autoreply

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I think it is hard to share a vehicle that has a limited range and an extended refueling time. I'm guessing you could make two sorties every rush hour. So, your expensive asset is effectively shared by two individuals - one with a pickup time of 6:30 AM and another who is picked up at 8:30. The evening commute would be similar.

Also, those landing pads would be necessary every mile, spread around the business areas of a city, so the high dollar users wouldn't have to walk very far to their offices. A guy isn't gonna go all-in on point to point transportation if he has to walk very far or catch a taxi...
In practise small rental electric city cars do about 8 drives a day so close to your numbers. Assuming interest, maintenance and depreciation are 50K a year that's about 20 US$ per flight. Sounds highly conservative to me ;)

Landing pad above every parking spot? A further network of small electric cars downtown can alternatively solve that. Google the Renault Zoe for an idea.
 

Kyle Boatright

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In practise small rental electric city cars do about 8 drives a day so close to your numbers. Assuming interest, maintenance and depreciation are 50K a year that's about 20 US$ per flight. Sounds highly conservative to me ;)

Landing pad above every parking spot? A further network of small electric cars downtown can alternatively solve that. Google the Renault Zoe for an idea.
How are you gonna cycle the aircraft enough to do that? Replace the batteries after every flight? Now <edited> we need serious charging, storage, and battery swap infrastructure and a crew to manage things at each little landing site.

If the automated airborne commuter concept is viable, why bother doing it as all-electric? Stick a motor in it, generate electric power, and run the fans. Have a 2 minute backup battery if the engine coughs. Voila, cheaper, more technologically doable, longer ranged, and less to fool with on a daily basis.
 
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cheesefactory

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All of what they claim seems possible, except for the range. Their claim of 193 mile range seems to be in Bizarro land. Either that's a massive exaggeration to get investors, or it's going to end up weighing like 8,000 lbs...half of which would be batteries. Designing a vtol aircraft with low energy density sucks because it's an endless of cycle of scaling up because you need more batteries to get better range, but then you need more power to carry the weight of having more batteries, so you end up needing more batteries because you need more batteries.

They made a full scale model that carried no payload none miles. That's cute and all, but not exactly impressive. When they carry 500 lbs 193 miles (both ways to compensate for wind), then we'll talk.
 
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