4 ms·

The Lilium Jet does not appear realistic to me, most VTOLs barely fly in the best of circumstances. It seems more like a scam to me. Not my field so I could be

The Lilium Jet does not appear realistic to me, most VTOLs barely fly in the best of circumstances. It seems more like a scam to me. Not my field so I could be wrong but the added efficiency of a canard is small change compared to the other challenges involved.

carabiner 2y ago
All of these electric VTOL urban air mobility things are hopeless. Various tech companies including google have taken a stab at them over the past two decades and none are anywhere close to entering service. Google shut theirs down. I really want them to work, but nothing gets past the physics/economics of batteries having piss poor energy density relative to fossil fuels and the massive inefficiency of small rotors. I think Boom has a better chance of flying than Wisk. Meanwhile, Uber Copter is up and running in NYC with regular helicopters.
schiffern 2y ago
Perhaps VTOL is entirely impractical and has no sizeable niche, but it appears Lilium is the least wrong out of all the existing VTOL physical layouts. - No additional draggy/heavy structures for the VTOL components, they reuse the existing wings - No large exposed props, which have noise and hazard concerns - Propulsors are synergistically combined with the wing upper surface, enhancing lift during cruise - VTOL mode actuators are synergistically combined with ailerons/elevators, reducing part count - They have wings for efficient long-distance flight (surprisingly some don't!) - Contingency ability for runway landing if the battery is too depleted - The aforementioned canard advantage If any of the VTOL schemes are workable (which is admittedly an open question!) it will be Lilium.
- cjbgkagh 2y ago
  It appears you’ve drunk the coolaid. I looked into it more and can now confidently say it’s a total scam. The stuff you’re talking about is window dressing.
  - schiffern 2y ago
    Maybe that's true! If you can elaborate on your confident saying with facts, sources, or explanations, I would certainly give it my full consideration. It wouldn't be the first time I've been wrong! What makes you think it's a "total scam"?
    - cjbgkagh 2y ago
      My prior for eVTOL these days is scam, but I googled ‘Lilium Jet scam’ and hit this; https://news.ycombinator.com/item?id=29651504 https://news.ycombinator.com/item?id=29651504 What I was looking for is someone to say it can’t work because of the math XYZ and for a person to say back that math XYZ is wrong because of ABC and that second part never happens. The stuff they talk about is window dressing and doesn’t answer questions like, where are your 500wh/kg batteries? I remember when Ballon Boy happened and I took one look at that Ballon and it was instantly obvious it wasn’t carrying a kid, but apparently others were still expecting to see a kid when the balloon landed.
      - schiffern 2y ago
        >My prior for VTOL these days is scam That doesn't answer my question. It just hides your 'scam' claim within your prior. _Why_ is your a priori expectation for all VTOL to be a scam? And does that generalized reasoning in fact apply to the specific case of Lilium? >where are your 500wh/kg batteries That's probably the least speculative out of all their bets. Moore's Law for microchips may have ended, but a similar (slower) scaling law for batteries seems to be holding for decades now. My prior is that batteries will continue on the same curve.
        cjbgkagh 2y ago
        You can also check out their stock price. Down from peak 92%, so at least to investors it’s looking less likely they’ll deliver instead of more likely. I gave a link in which others listed their rationale for why they don’t think it will work. Their availability estimates for battery capacity is double the long term rate of improvement - which seems unrealistic. But yah know with enough wh/kg just about anything will fly.
- kens 2y ago
  >If any of the VTOL schemes are workable... That reminds me of the "V/STOL Wheel of Misfortune", a diagram of 45 different V/STOL designs, of which four made it into service. https://www.cmlx.co.uk/hawkerassociation/hamain/wheelmisfortune.html https://www.cmlx.co.uk/hawkerassociation/hamain/wheelmisfort...
  - notahacker 2y ago
    On a similar note, the Aviation week ranking for current Advanced Air Mobility projects is named a "reality index"! https://aamrealityindex.com/aam-reality-index https://aamrealityindex.com/aam-reality-index (Lilium is in the upper middle of this, FWIW)
  - marcosdumay 2y ago
    On that case, past performance is absolutely not a guide for future results. The weight/power ratio of electrical motors is so different from combustion engines that it's a qualitative difference already. Just because nobody has ever been able to solve that problem, it doesn't mean that a lot of people won't easily solve it now.
- calmbonsai 2y ago
  Joby aviation seems the furthest along. Joby has completed many test flights that mimic its real-world route distances and energy-altitude flight regeimes. Its flight avionics package (essential for VTOL fly-by-wire) has received FAA certification. Related to Lilium and noise, Joby has a lower overall emitted dB energy and, specifically, a much lower dB signature in the human hearing range.
- renegat0x0 2y ago
  Huh. What about Volocopter? Appears to be entering market. https://www.volocopter.com https://www.volocopter.com
jillesvangurp 2y ago
Well a scam that is flying and more or less working as advertised at this point. You can watch testflights on youtube. Same for the Archer, Joby, Beta Alia, and a few others. Several of those are now doing manned flights and shipping prototypes to early customers. In short, they fly just fine. What makes you think things are a scam?
- chinathrow 2y ago
  While most of them fly just fine, the economics need still to be proven.
  - jillesvangurp 2y ago
    That usually comes after certification. Which some of these things are getting close to. I hear Delta is eager to start shuttling passengers from their terminals with Archer. At this point, you can start making some pretty informed statements about operational cost too. Battery life span and cost is a known factor. The cost of electricity is a known factor. There might be some nasty surprises with components, manufacturing, or scaling up production volume of course. But mostly these things are starting to look like they are getting there.
- hef19898 2y ago
  Well, what Lilium is flying is a demonstrator, not a prototype. The difference is that a prototype is close to the final product and test flights can be used in the early phases of the certification path, demonstrator flights cannot. Or to put harsher: all Lillium has is two model aircraft that have close to nothing in common with the 7 seater they are selling. And one could call it a scam, when tuh product you sell has nothing to do with the product you show (and no, mock-ups at airshows don't count at all), and the product you sell has, so far, no clear timeline until certification. The aerospace version of vaporware. Whether or not it amounts to an actual scam woupd be for courts to decide. Right now it looks a lot like Nikola, without the option to use a hill to fake the product demo. As a sidenote regarding test flights: last time I checked, those were unmanned, with a demonstrator and not a prototype and no longer than 6 minutes. Which is as far from what serious people in the field call a test flight of it could be. Good for PR and investors so, it looks cool. Also, one can make everything fly, if you put enough thrust to it. Doesn't mean you have product that can sustain a business.

carabiner 2y ago

All of these electric VTOL urban air mobility things are hopeless. Various tech companies including google have taken a stab at them over the past two decades and none are anywhere close to entering service. Google shut theirs down. I really want them to work, but nothing gets past the physics/economics of batteries having piss poor energy density relative to fossil fuels and the massive inefficiency of small rotors. I think Boom has a better chance of flying than Wisk. Meanwhile, Uber Copter is up and running in NYC with regular helicopters.

schiffern 2y ago

Perhaps VTOL is entirely impractical and has no sizeable niche, but it appears Lilium is the least wrong out of all the existing VTOL physical layouts. - No additional draggy/heavy structures for the VTOL components, they reuse the existing wings - No large exposed props, which have noise and hazard concerns - Propulsors are synergistically combined with the wing upper surface, enhancing lift during cruise - VTOL mode actuators are synergistically combined with ailerons/elevators, reducing part count - They have wings for efficient long-distance flight (surprisingly some don't!) - Contingency ability for runway landing if the battery is too depleted - The aforementioned canard advantage If any of the VTOL schemes are workable (which is admittedly an open question!) it will be Lilium.

cjbgkagh 2y ago
It appears you’ve drunk the coolaid. I looked into it more and can now confidently say it’s a total scam. The stuff you’re talking about is window dressing.
- schiffern 2y ago
  Maybe that's true! If you can elaborate on your confident saying with facts, sources, or explanations, I would certainly give it my full consideration. It wouldn't be the first time I've been wrong! What makes you think it's a "total scam"?
  - cjbgkagh 2y ago
    My prior for eVTOL these days is scam, but I googled ‘Lilium Jet scam’ and hit this; https://news.ycombinator.com/item?id=29651504 https://news.ycombinator.com/item?id=29651504 What I was looking for is someone to say it can’t work because of the math XYZ and for a person to say back that math XYZ is wrong because of ABC and that second part never happens. The stuff they talk about is window dressing and doesn’t answer questions like, where are your 500wh/kg batteries? I remember when Ballon Boy happened and I took one look at that Ballon and it was instantly obvious it wasn’t carrying a kid, but apparently others were still expecting to see a kid when the balloon landed.
    - schiffern 2y ago
      >My prior for VTOL these days is scam That doesn't answer my question. It just hides your 'scam' claim within your prior. _Why_ is your a priori expectation for all VTOL to be a scam? And does that generalized reasoning in fact apply to the specific case of Lilium? >where are your 500wh/kg batteries That's probably the least speculative out of all their bets. Moore's Law for microchips may have ended, but a similar (slower) scaling law for batteries seems to be holding for decades now. My prior is that batteries will continue on the same curve.
      - cjbgkagh 2y ago
        You can also check out their stock price. Down from peak 92%, so at least to investors it’s looking less likely they’ll deliver instead of more likely. I gave a link in which others listed their rationale for why they don’t think it will work. Their availability estimates for battery capacity is double the long term rate of improvement - which seems unrealistic. But yah know with enough wh/kg just about anything will fly.
kens 2y ago
>If any of the VTOL schemes are workable... That reminds me of the "V/STOL Wheel of Misfortune", a diagram of 45 different V/STOL designs, of which four made it into service. https://www.cmlx.co.uk/hawkerassociation/hamain/wheelmisfortune.html https://www.cmlx.co.uk/hawkerassociation/hamain/wheelmisfort...
- notahacker 2y ago
  On a similar note, the Aviation week ranking for current Advanced Air Mobility projects is named a "reality index"! https://aamrealityindex.com/aam-reality-index https://aamrealityindex.com/aam-reality-index (Lilium is in the upper middle of this, FWIW)
- marcosdumay 2y ago
  On that case, past performance is absolutely not a guide for future results. The weight/power ratio of electrical motors is so different from combustion engines that it's a qualitative difference already. Just because nobody has ever been able to solve that problem, it doesn't mean that a lot of people won't easily solve it now.
calmbonsai 2y ago
Joby aviation seems the furthest along. Joby has completed many test flights that mimic its real-world route distances and energy-altitude flight regeimes. Its flight avionics package (essential for VTOL fly-by-wire) has received FAA certification. Related to Lilium and noise, Joby has a lower overall emitted dB energy and, specifically, a much lower dB signature in the human hearing range.
renegat0x0 2y ago
Huh. What about Volocopter? Appears to be entering market. https://www.volocopter.com https://www.volocopter.com

jillesvangurp 2y ago

Well a scam that is flying and more or less working as advertised at this point. You can watch testflights on youtube. Same for the Archer, Joby, Beta Alia, and a few others. Several of those are now doing manned flights and shipping prototypes to early customers. In short, they fly just fine. What makes you think things are a scam?

chinathrow 2y ago
While most of them fly just fine, the economics need still to be proven.
- jillesvangurp 2y ago
  That usually comes after certification. Which some of these things are getting close to. I hear Delta is eager to start shuttling passengers from their terminals with Archer. At this point, you can start making some pretty informed statements about operational cost too. Battery life span and cost is a known factor. The cost of electricity is a known factor. There might be some nasty surprises with components, manufacturing, or scaling up production volume of course. But mostly these things are starting to look like they are getting there.
hef19898 2y ago
Well, what Lilium is flying is a demonstrator, not a prototype. The difference is that a prototype is close to the final product and test flights can be used in the early phases of the certification path, demonstrator flights cannot. Or to put harsher: all Lillium has is two model aircraft that have close to nothing in common with the 7 seater they are selling. And one could call it a scam, when tuh product you sell has nothing to do with the product you show (and no, mock-ups at airshows don't count at all), and the product you sell has, so far, no clear timeline until certification. The aerospace version of vaporware. Whether or not it amounts to an actual scam woupd be for courts to decide. Right now it looks a lot like Nikola, without the option to use a hill to fake the product demo. As a sidenote regarding test flights: last time I checked, those were unmanned, with a demonstrator and not a prototype and no longer than 6 minutes. Which is as far from what serious people in the field call a test flight of it could be. Good for PR and investors so, it looks cool. Also, one can make everything fly, if you put enough thrust to it. Doesn't mean you have product that can sustain a business.