[joshribakoff]

From what I gather most companies in the space plan to land and take off from rooftops. That leaves a lot more options for stations and edges connecting them leading to a denser network than something like a subterranean train which requires dedicated stations with tunnels in between them

[imposterr]

There's actually examples of this in the world now. In São Paulo, the rich take helicopters between buildings [1].

[1] https://www.theguardian.com/world/2008/jun/20/brazil

[mc32]

Even so there are only 469 (in 2008 according to the article) in all of São Paulo and that’s the metro area with the most helicopters in the world.

I doubt the likes of Hyundai are looking to sell their things “in the hundreds to thousands” range.

It’d a a big change in air traffic and noise pollution.

[malandrew]

You'd be surprised how far 469 heliports go. That's one more than the number of stations the NY Metro has, which is the metro with the most number of stations in the world. Now imagine you could travel as the crow flies between any station in NYC. That's awesome efficiency, and if you still need you can grab an Uber at street level if you're still not close enough.

You're also not limited to just those 469 heliports. The vertices of the convex hull they produce can all serve as jumping off points to go about a 100 miles further to heliports one may have in ones own home.

For the rich in São Paulo, that may be homes in places like Angra do Reis and Laranjeiras. Even places like those two (which sit between Rio de Janeiro and São Paulo, can serve as connection points to jump from São Paulo to Rio de Janeiro with only one or two stops in between the two cities.

When you eliminate the time in traffic traffic to get to Congonhas or Guarulhos and the time spent in airport security, it makes a ton of sense for those with the means. Eventually as the tech progresses and becomes cheaper it will become accessible to more than just the very very rich.

[seoulmetro]

No. Seoul Metro has nearly double that of NYC. I have no idea how you could possibly think NYC has the most in the world. Just think of most Chinese cities, let alone Korea's capital. https://en.wikipedia.org/wiki/Seoul_Metropolitan_Subway

[ta1234567890]

Also Tokyo, Japan. It's ranked first in the world on subway usage and has 882 railway stations. https://en.m.wikipedia.org/wiki/Tokyo_subway

[seoulsubway]

Actually Tokyo has much less than Seoul. You're counting railway stations, not subway stations. There's a large difference. Though the water is quite muddled, the easiest way is to actually look at the maps of the differing cities.

I was actually very let down by the metro of Tokyo compared to other Asian cities. Probably due to my high expectations.

[malandrew]

Thanks for the correction. Google failed me when I tried to look up the metro with the most number of stops.

[godelski]

They also used to do this in NYC a lot. Here's a Bloomberg video on it that also discusses why it failed https://www.youtube.com/watch?v=8nbz5VFilxY

[leeoniya]

that smog tho...

[azinman2]

Except those rooftops are very expensive real estate, that often already have other stuff on them. So to rent one, you need to pay a bunch of money, which increases price per ride and decreases total rides... that combo means this isn’t that realistic for wide spread adoption.

[OnlineGladiator]

In that case, what makes them more useful than helicopters?

[robotresearcher]

They aim to be much cheaper to run. Helicopters are mechanically complex so require a lot of maintenance, and have multiple single points of failure so you can’t skip the maintenance, and are demanding to learn to fly. The hourly rate of a helicopter is high.

Electric motors are simple and reliable and all these companies use multiples so have some redundancy. Multi-rotors require computer control for stability. With that done the piloting is easy.

[OnlineGladiator]

Sure, they're trying to make it cheaper. But all of the eVTOL designs I've seen can't autorotate, making them much less safe (contrary to your implication about redundancy).

Everything I've seen about this space is people with big checks trying to cut corners to enter a new market, and it seems ripe to fail much like the 737-MAX.

https://www.forbes.com/sites/jeremybogaisky/2019/12/01/insid...

And that's ignoring all of the problems with the market itself, not to mention regulations, as well as logistical headaches of transporting between rooftops (which by the way, many cannot safely support landing pads - so now you also have to retrofit skyscrapers with incredibly expensive infrastructure).

To be fair you answered my question and I'm just being belligerent, so thank you for the response.

[robotresearcher]

The argument is that you don’t need to autorotate if you can land under control on 2/3 of your 16 motors and the failure rate of each is epsilon.

[smattiso]

The likelihood of failure is much lower with an eVTOL than a conventional helicopter. Additionally a BRS chute could work with eVTOLs in a way it couldn't with a normal heli.

[OnlineGladiator]

> The likelihood of failure is much lower with an eVTOL than a conventional helicopter.

You're basing this on a myriad of assumptions as eVTOL designs are barely at the prototype stage right now. Helicopters have been in use for decades, so we know how safe they are.

If they truly prove to be safer then that's awesome, but based on everything I've seen I don't believe that to be true.

[smattiso]

Why don't you believe that to be true? There are a myriad of ways for a combustion powered helicopter to fail. Just look at how many billionaires have been killed in helicopter flights.

Electric motors do not fail as often as combustion engines. Most eVTOL designs have redundancies that don't exist in a normal helicopter. I have flown R22s a handful of times and there were many times where an engine failure would have been disastrous.

[malandrew]

What makes you think people aren't working on all the problems you think they are ignoring? I personally know at least one person working each and every one of the problems you mentioned.

[OnlineGladiator]

Just because they're working on the problems doesn't mean they're going to solve them. When you look at all the pieces and read that article about the clusterfuck that is Kitty Hawk, you start to get a sense of just how much buzz and how little substance there may be.

FWIW I've interviewed at many of the eVTOL companies and found too much sizzle and not enough steak.

But to each his own. Ultimately it's just my opinion. Reality will assert itself regardless of what I think.

[ngoel36]

They are all-electric, 100x quieter, notably safer, and significantly cheaper by the mile.

[agumonkey]

do these have clear benefits compared to choppers ? open question.