[MichaelCollins]

Isn't it the number one reason all "flying car" proposals are doomed to fail? They don't violate physics and the '3d driving is too hard' problem could in principle be solved with software. But they simply don't fit into our society. They literally don't fit. Even if you can fit a VTOL on a suburban driveway, it would be too dangerous and noisy to not get banned. The space requirements are such that they could only work in rural areas, which severely limits their utility and consequently their commercial viability.

[radu_floricica]

Roofs? I mean, bringing a flying thing on a busy city street where it has to contend with everything from wires to delivery drones does seem like a bad ideas, but landing on the roof of your office building is pretty much ideal, and doesn't seem to need major infrastructure.

You won't be able to call one up to a street corner, but that doesn't necessarily mean there's no money to make. The first thing they'll do is just take the helicopter market and slide the supply/demand curves to wherever they can go at 1/10 of the price. Only when this is done they need to look for completely different models.

[cush]

The helicopter market doesn't really cover personal transport, unless you're talking about the ultra-rich. And unless the roof of an office building already has a heli-pad, it's not getting landed on.

[radu_floricica]

One could argue the classic path of technology is to bring to everybody what was once available only to the ultra rich. There was a nice infographic on how an iPhone replaced roughly a million worth of equipment in the 90s.

The ultra-rich heli market may be small in relative terms, but it's there. Much easier to expand it 100x than to build a new one. And once you do, you're in a good position to try something else - your tech is proven, you have a fleet, you're bringing in cash.

[cush]

The iPhone analogy is a bit of a stretch. I'm not sure what "millions of equipment" it replaced. If you're referring to software, the PC or Blackberry was already accessible to those who weren't ultra-rich.

As for the heli market, the vehicle holds one person, not 2+, and can't fly as far as a heli. But it is less about consumer demand and more about the infrastructure, excessive noise, airspace constraints, and the dozens of other public-facing issues that would arise with any attempt at expanding that market.

[MichaelCollins]

Helicopters have already been greatly restricted / banned in some cities, particularly NYC.

[ncmncm]

Mostly for noise, and safety. Those blades slicing past worry people.

It is hard to believe these will be very much quieter than a chopper.

[MichaelCollins]

Safety particularly. In 1977 on the heliport of the Pan Am building (aka the MetLife building), a helicopter's landing gear broke which caused the helicopter to tip over and the rotor to break. Pieces of the rotor killed four people on the roof, fell to the street below, and killed another person on the ground. It took emergency responders about an hour to get onto the roof because the elevators in the building shut down. The public was already wary of the danger of helicopters (as well as being annoyed by the noise), and this incident confirmed their fears. Since then, heliports on buildings in NYC have been severely restricted, for a time banned completely, I believe, but 3 rooftop heliports are still active in NYC.

Another helicopter crash in 2019 suggests another danger. A helicopter crash landed on the roof of a skyscraper and caught fire. The pilot was the only person killed that time, but it took firefighters about an hour to put the fire out. They apparently got it under control without too much difficulty and were lauded for a quick response.. but what if that helicopter had been packed full of lithium batteries? Lithium battery car fires are notoriously hard to put out. Such a fire on the roof of a tall building seems like a serious concern to me.

[magic_hamster]

There is no way the iPhone replaces equipment valued at 1M.

[radu_floricica]

"valued at 1M ten years ago". If you add up stuff like GPS, sat phone, camera, video conferencing gear and so on, it gets expensive fast. We've had all of that stuff for decades, it's just nobody could afford it.

[cush]

But the iPhone didn't replace that stuff. There's still so much software and infrastructure involved. For example, you can't do video conferencing on 3G. The iPhone didn't bring with it 4G LTE

[benj111]

I wouldn't be surprised if some $1M dollar piece of equipment was replicated in a smart phone.

Hell, the blue led was invented in the 90s, how much would you value the first blue led at?

[nradov]

Sure it's possible to build helipads on roofs. But those usually have to be designed in from the start and very few buildings have them. It's tough to add one to an existing building due to weight limits and obstructions from antennas and HVAC machinery. Real estate developers won't take on that expense until VTOL aircraft become more popular, so it's a "chicken or the egg" problem.

[radu_floricica]

I looked up some weights. Helicopters (other than ultra-light) are measured in tons, and that's indeed something you don't want on a roof that's not designed for it. But this kind of VTOLs will most likely be equivalent to ultra light helicopters, so I can imagine building a metal platform on top of the HVAC machinery.

[nradov]

No these eVTOL air taxis will have to be roughly the same weight as a regular turbine powered helicopter in order to be able to carry a useful load. Batteries are heavy.

Ultralight helicopters are limited to 254 pounds vehicle weight. While that does make it easier to build suitable rooftop helipads without major structural renovations, such aircraft can't be used for air taxi service. It isn't legally allowed, and even if the law was changed they wouldn't have enough load capacity or range to do anything useful.

https://www.usua.org/Rules/faa103.htm

[ComodoHacker]

More like they'll take the luxury cars market. You don't have to drive/fly one regularly, owning is often enough.

[snickerbockers]

I wonder how well they'd scale if they became wide-spread enough to actually be an alternative to ground-based transportation. Would there need to be a complicated air-traffic control network to prevent collisions? Would there be "flying roads" complete with their own traffic jams like in the jetsons? Would popular destinations have long queues of vehicles waiting for their turn to land on the helipad?

[nradov]

We already have an air-traffic control network to prevent collisions. It works pretty well, except for general aviation aircraft without TCAS flying under VFR near non-towered airports.

https://www.planeandpilotmag.com/news/2021/06/14/plane-facts...

We already have flying roads to manage an orderly flow. Air traffic controllers will sometimes hold aircraft on the ground to prevent congestion and maintain the minimum safe separation intervals. At busy airports sometimes aircraft are forced to circle in the pattern several times waiting their turn to land.

[snickerbockers]

I know that, but thats for a comparably small number of large aircraft landing at a single designated location. It wouldn't scale at all to a city-wide air taxi service.

[nradov]

It's not just for large aircraft. ATC manages flights to many smaller airports as well including charters and private aircraft. The system scales pretty well. There's no realistic prospect of having thousands of air taxis in flight at once above a single city, that's just never going to happen and not worth considering.

[seanmcdirmid]

They could work in Alaska where personal bush and float planes are common. VTOL would avoid having lakes filled up with float planes.

[MichaelCollins]

Maybe, but I think range and cargo capacity are important to Alaskans that rely on bush planes. VTOLs, particularly electric ones, can't compete in these regards.

[benj111]

Really? I would have thought the 3 down sides to electric planes would be refuelling infrastructure. Sensitivity to cold, and limited range.

[seanmcdirmid]

Most of these planes are used as puddle jumpers in the first place: they aren't used because of the long distances involved, they are used because of terrain. Refueling infrastructure is pretty easy (Alaska has grids, A LOT of localized hydro).

[nradov]

I don't see how the piloting problem could be solved with software. These new VTOL aircraft are going to have to be in the same airspace as other light aircraft flying under VFR. How are they going to see and avoid without a licensed pilot? Cameras aren't good enough yet in adverse lighting conditions.

[bobsil1]

At least one fits in 3 parking stalls. Renting them like Electrify America.