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Comment by djrogers | Hacker News Reader

These are som pretty impressive goals. If they can truly achieve a hover state as quiet as 60db, and get the efficiency they've outlined, these could truly change the way we look at short-haul travel.

The idea of a 2 hour drive from a small town to the big city being reduced to a 1hr flight (with no airport - yay helipads) is already a market where helicopters are making money. Doing that in even less time, in more comfort (ugh - choppers are loud), and at lower cost per hour/mile will change things dramatically.

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It might actually be too good to be true. The German magazine Aerokurier is citing experts that seem to have doubts about feasibility [1].

The category is called air taxis, other competitors are Volocopter and Archer, with different concepts.

[1] https://topgear-autoguide.com/category/sports-car/futuristic...

Experts always have questions about disruptive technology.

They are often not right, since disruptions are not incremental change, but tons of nuanced ones that lead to a significantly better overall system.

Edit: "Often" does not mean always, or the majority of the time. Lilium is clearly not a scam, and seems to be making steady progress towards their goals.

...but physics isn't something that cares If you want to disrupt.

I think this is such an important point to differentiate. Yes, incumbent experts can be caught flat-footed when a new technology comes along that is essentially just much better at what they do. Best example in my mind is the iPhone, where essentially the big old-school cell phone execs totally poo-poo'ed Apple's ability to create a compelling cell phone in 2008: "A computer company doesn't know what they're doing."

But that is fundamentally different than pointing out real physical limitations of an idea, and the danger is you get exactly the OP response, "The old guard always dismisses you until you change the world!" yada yada. This is basically exactly what happened with Theranos - anyone in the actual field of microfluidics knew it was all bullshit.

Of course, but it seems like the gap between what is physically possible and what has been demonstrated is pretty large when it comes to aircraft. Has anyone made a specific argument that Lilium violates the laws of physics?

How energy efficient is this concept? Can't this air taxi thing be done with better public transport and urban design?

Air taxis are unlikely to become as common as the industry hopes.

But helicopters are already viable. Increase reliability, drop upfront/operating costs an order of magnitude, and make it autonomous to remove cost of a pilot; then you have a lot more cases where it would be a viable option.

> Experts always have questions about disruptive technology. They are often not right

They're usually right, because most technology that seeks to be disruptive doesn't end up working.

"Futuristic air taxi: is the Lilium jet a blow job?"

Is "blow job" a literal translation of a German phrase?

That whole article looks and reads like an automatic translation. I’m guessing the original says “Ist der Lilium Jet eine Luftnummer?” Or perhaps “Luftpumpe”. A “Luftnummer”, an “air number”, is “hot air”. A “Luftpumpe” is an air pump but can also mean someone is a BS artist.

There’s also a bit of a bad pun hiding in there if it was “Luftnummer”, because “eine Nummer schieben” means to have sex, colloquially. If you really wanted to preserve that … you’d reach for the “blow job”.

Aerokurier has an axe to grind with Lilium. That their initial coverage caused quite a stir up just motivated them to continue down that road.

Doesn't mean Lilium is actually a guaranteed success, just that Aerokurier isn't the most balanced source.

60dB @ 100m is 77db @ 15m

For comparison, in Washington state, the legal limit for an automotive exhaust is 72db@15m.

Still an achievement, but definitely not something you want your neighbor to land at 3 am.

Can we please use dBa (a measure of absolute sound pressure) rather than dB (a relative term used in many domains)?

Obviously aircraft are louder than cars. It seems like this should be compared to a helicopter since it uses the same pads.

They should be compared to vehicles that occur in the space that these "air taxis" are meant to take off and land in. If they're relegated to airports, fine, compare to helicopters. If they're meant to take off and land in my neighborhood, compare them to cars.

How is 2h to 1h any „revolution“? And wouldn‘t simple (bullet) trains be better for that?

New train lines won't be built ever again in the United States

> New train lines won't be built ever again in the United States

New train lines are being built now in the United States.

There's construction ongoing on new train lines in the United States. Whether they're being built is up for debate.

A small town doesn’t have the density for a HSR link, see eg China’s HSR debt.

A 120 mile link at 14 million a mile is more than a billion dollars.

I really doubt that at any appreciable scale eVTOL is nearly as cost effective as HSR, no matter how expensive that is

A bullet train is better if there's one that already happens to go from your location to your destination. If they manage to make these VTOL planes safe and cheap enough, they'll be far easier to deploy than any train system. Also while there's overlap between short haul aviation and train markets, the infrastructures don't have to be mutually exclusive.

You are thinking the classic hub and spokes transport network where you have to travel to a major city with an actual bullet train station travel to another big city at high speed and then do an uber/taxi/whatever to get to and from the station on both sides. In the extreme case, this would be more of a point to point kind of thing. Walk to the nearest flat surface where one of these things can land and wait a few minutes to be picked up. Your local super market's parking lot would be big enough. On the other side, you land at a similar venue and then walk to your destination in a few minutes.

Most cities could end up with hundreds or thousands of suitable locations for these things to take off and land long term. So, about similar to the density of subway stations or better. But a lot cheaper to build.

I would say, at least in the near/medium future, the fact you'll never hit a traffic jam for a 1 hour commute is a big plus.

But then again, weather probably will ground it more often.

The ultra rich in London, NYC, and LA: you can live 2 hours as the crow flies by car (which would be 3-6 hours depending on traffic) and cut it to an hour or less.

Or you can plop your floating megamansion offshore and commute to the city from there.

Bullet trains are point to point, and you have transit to station overhead. This is more direct above and beyond an absolute speed advantage.

My take was actually the opposite. I can't see this changing anything.

Since this thing won't be able to take off from my driveway or land at my destination, I figure it will still take 2 hours to go door to door. Once you arrive, you'll still need your own transportation too.

Unless this is somehow cheaper and more comfortable than driving, I can't imagine ever using something like this.

Yea, 60 decibels at 100m would be pretty crazy to achieve.

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