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You are ignoring the fact that cars have to navigate what is basically a set a of 1 dimensional corridors on a 2 dimensional plane. Airplanes don't have these limitations and can fly point to point at their choice of altitude.

Currently most of the congestion in aviation is around airports which are necessarily optimized for large jets. With a small airplane, you can fly to a much larger variety of airports, around ~50K world wide and it's relatively straightforward to build even more of them as needed.

Noise is a function of propeller size, rotation speed, and engine noise. Simply put, lots of small propellers rotating at faster speeds driven by electrical engines are a lot less noisy than larger props driven by combustion engines. The physics around this are complex and involve things like the speed of sound of the tips of the propeller (you break that limit at lower rpm for larger props), the mass and thickness of the propeller, vortices, etc. Basically, all of that improves with smaller props.

Compared to a loud helicopter, an electrical plane at the same altitude could be a lot less noisy to the point where in a busy city you'd hear one but not the other above the ambient noise.

I'm guessing that the break-even point on space efficiency is somewhere close to the point where you invent Blade Runner-style levitating cars that require zero extra space for take off and landing, and can move arbitrarily slowly, or even come to a complete stop, without falling out of the sky.

Without that, I doubt that that adding some room for vertical stacking would offset the amount of additional lateral space they end up needing.

And I believe that effect would be intensified by the the amount of vertical stacking you can reasonably do being constrained by how far a vehicle needs to move laterally in order to gain or shed a given amount of altitude, and the distance of the trip being made. For a traditional fixed-wing aircraft operating over "urban commute" distances, that constraint would be downright tyrannical. For Blade Runner style levitating cars, it would be no big deal.

> cars have to navigate what is basically a set a of 1 dimensional corridors on a 2 dimensional plane. Airplanes don't have these limitations and can fly point to point at their choice of altitude.

That's not entirely correct. Planes also have corridors in the sky. Just like roads, there are the highways (with different altitudes for different directions) and slower lanes for smaller aircraft. And airports are basically a confluence of many lanes, which requires a coordination (air traffic controllers).

https://en.wikipedia.org/wiki/Airway_(aviation)

Depends on what class of airspace you are in and weather you are flying under IFR or with some kind of flight following & flight plan. But even then the air ways can be stacked vertically.

If you are flying vfr and in an airspace where that is allowed, you can pretty much go where you want as long as you stay away from controlled areas. Basically most helicopters fly VFR. The recent accident with Kobe Bryant involved a VFR flying helicopter flying into fog in LA.

True, but to provide reliable commuting you pretty much have to fly IFR, especially in a place like SF Bay or LA. This is because often marine layer clouds don't clear until 10am and people want to be at work long before then.

It may be possible to do a lot more to improve the availability of IFR approaches and routes if we factor in automated systems. It's going to take a lot longer to build more airports, but I can tell you that pretty much every airport manager in the United States will be thrilled to face that problem.

Yes, but these are just by convention. Some pilots argue quick forcefully for allowing point-to-point navigation to save fuel and time.

In any case, it's easy to set up another "road" just a few thousand yards north, south, east, west and up or down.

The FAA is trying to eliminate the need for those corridors under the "Free Flight" program, however progress has been slow and it's unclear whether this approach will ever be fully implemented.

>You are ignoring the fact that cars have to navigate what is basically a set a of 1 dimensional corridors on a 2 dimensional plane. Airplanes don't have these limitations and can fly point to point at their choice of altitude.

Absolutely true. However cars are mostly autonomous and airplanes flying through urban airspace are not, with rare exception. The bottleneck will be our air traffic control system, which can not in its semi-automated form scale to the volume required and would not qualify for the usual SV "move fast and break things" treatment, since "breaking things" in this context would be in-air near misses and collisions.

True, this is as much a cultural and legislative problem as it is a technical problem. IMHO, having lots of autonomous capable planes will create a need for having them interact with some form of automated traffic control that does not yet exist.

Building that technically is much less of a challenge than getting it certified, standardized, and integrated in the aviation world.

IMHO this will play out over decades and will be driven by increasing traffic volumes of basically fully or semi autonomous vehicles causing issues with the current system.

But if you think about it, doing things the way we have been doing for the last 70 years with analog radio broadcasts, call signs, people using archaic jargon, chattering about altimeter settings, verbal communication of flight plans, having to monitor multiple radio frequencies, etc. is maybe not optimal in a world where all that info could be exchanged in ms between two autonomously operating systems.

Yup yup - I'm not defending the status quo as much as just commenting it's not built for the future utopia of self-directed or autonomous private aviation. Commercial aviation puts pressure on Congress now to try and marginalize general aviation due in part to system constraints; every private flight that displaces a commercial one is revenue lost as far as they are concerned.

Autonomous air traffic control is far further along than you think it is.

Would appreciate some pointers for that; I'm interested in this space. My understanding is that governmental institutions are moving at a glacial pace here. E.g. ADSb took decades to get deployed (mandatory in lots of places as of the beginning of this year) and is technically less than ideal because of a lot of design by committee stuff interfering.

I'm aware of some automated ATC efforts on smaller fields that would otherwise be uncontrolled.

Have you seen/heard recently built rescue helos in action? Been very surprised by them. The loudest thing is the whine of their turbine, but not that loud at all. There are many louder cars and motorcycles on the street. I don't know the type anymore, but it was something built by Airbus Industries, based on some Eurocopter platform. Worlds apart from those old Bell UH-1s!

> Noise is a function of propeller size, rotation speed, and engine noise

Yes and also the frequency of sound, which is another factor of complexity as to how that propagates.

I believe they will be use for the same thing helicopters are used today:

1-Emergencies and organs transplant. No pilot means more carry load in volume and weight.

2.As a status symbol for top of the ladder executives and polititians. They will go from the top of skyscrapers to their mansions just looking down of those that waste their time in car jams.

I see this being useful for short distance travel as well, but not that much in cities, but outside them.

It's still a plane, it has no VTOL capability. It cannot be used for what helicopters are used today.

the parent of your comment is referring to the phrase “urban air mobility market”, which the X-57 PR video demonstrates as being small aircraft, a few of which were VTOL craft -- not the X57 itself.

The PR video was basically hinting at the X57 being a technology demonstrator which will showcase techs (like electric propulsion) that the so-called “urban air mobility market” can then take off running with.

> "It's still a plane, it has no VTOL capability. It cannot be used for what helicopters are used today."

This one, yes. But there are many "urban transport" VTOL electric aircraft in development. The idea is to combine the utility of a helicopter with the efficiency of a fixed-wing, while adding the environmental, reliability, and O&M cost benefits of electric.

I believe that, in the coming years and decades, electric VTOL aircraft will replace traditional helicopters for many applications.

Ha. Organ transplants. Only on TV. My sister runs organs as a volunteer. Commercial flights, no special consideration.

Ya, I did a ride along with the highway patrol once. 1 hour of that shift was driving to the far end of our coverage area and waiting for another car. Then blazing down the freeway in the opposite direction at 3am at top speed on what they call a "blood run" (organ in a cooler in the trunk). There are no commercial flights at this time of day and the organ was moving about 5 hours by car. This would have been much safer and faster if it were done by helicopter or small plane, but I guess if the car works then they don't have to use aircraft.

Completely depends on the organ. Kidneys can survive outside the body for 1-2 days, while heart and lungs only survive 4-6 hours and are typically transported via ground or air ambulance, depending on distance.

Source: https://www.organdonor.gov/about/process/matching.html#expan...

Actually a company called FlyBlade does helicopter organ transplants. You should tell your sister to reach out to them.

https://www.foxbusiness.com/markets/blade-nyu-langone-transp...

Unless they are willing to do it for free, I don't think their sister who already does volunteer work can consider it.

And at a large Midwest hospital. But with the advent of professional "Hospital Administrators" with a degree and everything, hospitals become a business. Anything they can get for free, they do.

The thing is that cars (and bikes, and to some degree planes) are point-to-point. This decentralized mode of transportation is much more efficient when it comes to satisfy the needs of many commuters. For instance, by bike I save at least half of the time compared to Subway. And I have access to a well-developed subway and I do not need to change.

I agree, though, that planes will never be a replacement for cars or even bikes. That is because the utility per € is much higher for the former. A bike is generally cheap. A car is much more expensive but can carry four or more persons very far in pretty much every weather. A small electric plane is going to be even more expensive (conjecture) but otherwise worse than a car.

Agreed except the fabled concept of the flying car which NASA has been tinkering with for a long time. (Don't know if they still do. Not tinkering with as in actually building it, but thinking about "lanes" in the air, collision avoidance and such.)

I don't see why any electric vehicle can't be part of the sustainable urban transportation future.

There is no one-size-fits-all solution. Would it be better if we built cities around public transport? Generally yes. Does that mean there isn't a place for electric aircraft, electric cars, and smaller personal electric vehicles (bicycles, scooters, segways, hoverboards, skateboards)? Nope. I don't think anyone in this thread thinks that all of our future transportation needs will be satisfied by flight.

And given our current state of global pandemic, I think we can probably agree that even without the pros of other forms of transport, public transit has its own unique downsides.

Right but the comparison is being made against "ground transportation" in the video. Light aircraft are already a component of urban travel (notably helicopters) and merely making them electrically powered isn't going to dramatically increase their utility which again is what the visualization in the video shows.

Making them electric is fairly important for a carbon-neutral/negative future though.

Also even without helicopters being fossil-fuel powered, they have a number of other downsides: not nearly as safe as winged aircraft, louder, harder to fly, etc.

Yes it's a great idea to make electric aircraft for all sorts of reasons. Notably this design (as per the paper linked elsewhere) gets 300% more efficient for just switching to electric motors.

I'm giving context to the discussion from the parent of this thread. The nascent category of aircraft is being heavily marketed as a replacement means of transport for commuters. Which is why people are talking about them in that context.

While I agree about the hope for this being a solution to mass transit in urban areas...

Cars don't merely require "space", they require space that has road on it with tarmac and signs and lights and junctions, and they require it in a limited 2D plane and that is the same 2D plane that we need space for buildings etc.

Planes work in basically any space and require no infrastructure.

There is a metric shit tonne of space for planes right now just waiting for use. The same is never true for cars.

You got it wrong. Airspace over cities is very limited. At some point you get to the height in which long distance flights travel. Also, all aircraft have a minimum required safe distance between them tht needs to be large due to aerodynamics. This it become physically impsible to increase traffic density beyond a certain, low threshold.

I believe the overall goal of urban+suburban mobility is to increase the number of modalities of transport available. So adding scooters, busses, trains, uber, helicopters, planes, boats, etc.

Cars move in a 2-dimensional space (surface), aircraft move in a 3-dimesional space (without costly highways), so you can utilize space way more efficiently and move more people per square mile.

The safety distances will probably reduce due to automated collision-avoidance systems which may become mandatory in dense flight areas.

Although, I don't know how planes compare to cars in terms of energy utilization efficiency. A car only needs energy to move. A plane needs energy to move and stay above the ground.

Aircraft require significantly more space between them in order to operate safely so I doubt the efficiency is there even taking into account stacking in an extra dimension. They're also pretty weather dependent in comparison to other options so capacity can vary a lot.

If we actually cared about efficiency in urban transport we wouldn't have personal vehicles beyond bikes and small electric vehicles. We'd rather rely on public infrastructure like subways, trams, trains and buses.

Nothing can move more people than a subway, certainly not single person planes that need to land and still consume space when not in use, just like cars.

Nobody is saying that small aircraft will move more people than subways.

There is no one-size-fits-all solution to modern transportation needs. Compact electric planes are one piece of the puzzle.

I really don't see electric planes having a substantially larger market than helicopters.

There are a number of reasons electric planes are better than helicopters:

1. easier to fly

2. safer in failure scenarios

3. quieter

4. more energy efficient

> Cars move in a 2-dimensional space (surface), aircraft move in a 3-dimesional space (without costly highways), so you can utilize space way more efficiently and move more people per square mile.

You still need to land planes 1 at a time, and that involves a clearing period between landings.

Facts never stood in the way of PR.

Anything positive to say about this though?