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.
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.
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.
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 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.
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.
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.
Imagine thinking stock price pegged to peak price indicates company value. :-/
> I gave a link
From your link:
> my engineering mind recoils at the complexity of the design. The variable pitch blades, the adjustable exhaust nozzles, the tilt-wing vectored thrust system, etc. With complexity comes...
The variable nozzle is still present[1], but Lilium long ago dropped variable pitch[2]. "Tilt-wing" is also inaccurate, since they only move the (already moving) aileron and elevator surfaces, not the wing and its associated structures.
Hopefully this can help clear up these (hastily-Googled) concerns.
>Their availability estimates for battery capacity is double the long term rate of improvement
This is an interesting claim that I'll look into, thanks. Do you have a source? I found a few slide decks but I couldn't immediately find this part, so any help would be appreciated.
I do expect in the nominal case that Lilium will take perhaps twice as long to come to market, so in the end the delays may roughly cancel out. Time will tell.
Note that battery density will effect all eVTOL startups equally, so it's not really a competitive disadvantage for Lilium per se, but rather an overall industry challenge. And I agree, there are many challenges facing the industry!
What you have shown me has not convinced me to change my opinion and I'm not trying to change yours. The people that I know in the industry focus on certification timeline being overly optimistic which while most defiantly true is less interesting to me than the battery tech, or even the sociology as to why people get so attached to this - like that Nuclear-Powered Sky Cruise concept that many people shared unironically.
No doubt a lot of amazing things can happen with an large increase of wh/kg which is why I think it's incredibly weird that so much effort was put into things that are not that, Lilium has special investments in battery tech with Ionblox, the only interesting question to me is 'is that paying off?'. Not how much % of efficiency can be saved with a canard design - that's window dressing. Also, if they have this amazing battery tech then isn't that the most valuable thing they have and is eVTOL really the best application for it, why not double the range of electric cars instead. Even if they think eVTOL is the best use case then why not run on a skeleton crew until the battery tech arrives, or at least properly test their designs with onboard generators.
Waiting for battery tech is like waiting for engine tech and since so many engines end up vaporware so do all the nice aircraft designs dependent on them.
But sometimes new engines do deliver. The RED Aircraft V12 engines are amazing and should enabled the Otto Celera 500L to work really well. The DeltaHawk engine but they might actually end up delivering a really nice reliable engine. Part of that is a combination of long term stagnant general aviation engine technology and reduced tooling costs for manufacturing with CNCs. So there was a lot of low hanging fruit waiting to be picked.
Obviously Lilium Jets initial claims were wildly unrealistic, I think their current claims remain unrealistic, perhaps by the time they 'deliver' they've scoped it down to small hops. If they plan on selling something that can carry 7 people (they've already sold 20?) then perhaps I would believe it more if they demonstrated something working with 1 person and a whole lot of performance to spare.
