
Japan’s Entry in Flying-Car Race Takes to the Air - psim1
https://www.wsj.com/articles/japans-entry-in-flying-car-race-takes-to-the-air-11598691548
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manfredo
Aren't flying cars called, "helicopters"?

Perhaps a bit too snide, but helicopters can take off and land vertically and
can carry roughly as many people as most passenger vehicles. And they're
mature technology that has been around for over half a century at this point.
The problem of moving people through the air without a runway for takeoff and
landing has been solved for 60+ years.

What advantage does this flying car have over a helicopter? It's a quad rotor
craft so presumably is mechanically simpler (no swashplate) but at the expense
of lower speed and reduced ability to operate in the wind. Also it means a
crash if any of the four rotors fail (no autorotation). It can also drive in
the road like a car. But on the other hand it looks like it seats just one
person, and in an open top vehicle so it'll be uncomfortable in the rain.

Helicopters are already supplemented by cars in most use cases. I don't really
see the advantage of a flying car over flying a helicopter to the nearest
heliport and driving in a car the rest of the way. The only real advantage is
the fact that there is no vehicle change. But that comes at the expense of
using a vehicle that makes major sacrifices to both fly and drive on roads.

~~~
Torkel
This is true, but also not true. Helicopters are stuck as a concept: large
main rotor and tailrotor and also expensive parts and traditional aerospace
practices. There are other physical paths, e.g. Osprey, Cheyenne.

But the big thing now is batteries and electronics and brushless motors. It
allows flight at a whole new level of cost/safety.

Compare with toy-drones - your point here to me reads like ”there’s nothing
new with these quad-rotor drones, we’ve had gas rc helicopters since forever”.
And that is similarly wrong as saying these new vtol concepts are just
helicopters. Fundamental tech enables the concept of flight to be reinvented
using first principles. We know a bit of where this is going in small quads.
For manned flight it is still unknown.

~~~
manfredo
Helicopters are "stuck" because they've largely settled into an optimal
configuration over the 70 years if experience designing helicopters. Some of
the first helicopters had multiple rotors [1], but those were abandoned for
good reasons They have a large main rotor because larger rotors provider
greater efficiency. The single large rotor also provides the ability to
perform autorotation in the event of power failure. Batteries are also bad
choices for aircraft since they have very low energy density by unit of mass
[2] combined with the fact they don't get lighter as energy is expended like
thermochemical fuel.

These are the main reasons why quadro copters largely remain in the realm of
drones and toys. These are the use cases where mechanical simplicity of four
fixed pitch electric motors shine, and the shortcomings of reduced safety and
lifting power aren't big issues (cameras weigh less than people and their
families don't sue when they get smashed in a crash). You point out
helicopters aerospace practices as a drawback, but in reality those practices
emerged to deal with the responsibility and demands of human air transport.
What is it going to cost to insure one if these flying cars? How many people's
life insurance policies is going to cover rides in these things?

Definitely quadrocopters have made their mark in consumer electronics and even
some commercial applications. But I am very dubious that people will be flying
in electric multirotor craft.

1\. [https://en.m.wikipedia.org/wiki/Focke-
Wulf_Fw_61](https://en.m.wikipedia.org/wiki/Focke-Wulf_Fw_61)

2\.
[https://upload.wikimedia.org/wikipedia/commons/thumb/c/c6/En...](https://upload.wikimedia.org/wikipedia/commons/thumb/c/c6/Energy_density.svg/1920px-
Energy_density.svg.png)

~~~
kevin_thibedeau
> The single large rotor also provides the ability to perform autorotation in
> the event of power failure.

That's a nice fantasy but when the SHTF nobody ever seems to be able to pull
off an autorotation landing without fatalities. You need enough forward speed
and control authority to make it work. An incident when you're at or near
hover is unrecoverable.

~~~
manfredo
An incident at or near hover is close to the ground, and so has much better
chances of survival.

The issue with multiple rotors is that if one rotor fails the craft
immediately pitches over and crashes. The Chinook solves this because the two
rotors have a linked shaft. Definitely a quadrocopter becomes unstable with
only 3/4 rotors. Maybe the octocopter posted elsewhere in this thread can
sustain one failure and still land.

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cevans01
Flying cars are interesting because they have the potential to partially make
obsolete the natural monopoly of roads. Governments are heavily involved in
natural monopolies (possibly for good reason) but I worry that that
involvement may crowd out innovative private organizations that would
otherwise have the incentive to bypass the natural monopoly. I wonder what
other innovations are being stifled in the same way.

As far as flying cars go, they sure are loud. But cars are fairly noisy as
well -- in cities the roads are often very close to apartment buildings.

~~~
notahacker
You run into the natural monopoly of airspace instead.

There's more room up there, but owners of the land beneath and users of other
aircraft alike have a vested interest in the skies not being a free-for-all,
and sure enough it's government agencies stepping into the air traffic control
and regulation breach.

~~~
tinus_hn
That’s pretty hard if traffic is not confined to roads and journeys don’t need
to start at an airport.

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mrfusion
The comments here are why we don’t have flying cars.

Everyone thinks of every possible negative. Instead of asking why not we
should we asking what if. Maybe think of solutions along with the problems you
find.

~~~
nradov
What if we could decrease the force of gravity? That would be a great
solution.

~~~
mrtnmcc
Yes reducing mass would be a good general approach.

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Yoric
So, what is the attraction, exactly? It doesn't look as fast as a car or any
more convenient, at least until cities are redesigned to accommodate these
vehicles. I also assume that it is more energy-hungry than a car and I imagine
that accidents are bound to be worse than cars for the foreseeable future.

Is it safer to pilot than an helicopter?

------
Animats
eHang is further along. [1] 16 rotors.

Battery energy density seems to be the big remaining problem. Flight times are
too short.

[1] [https://youtu.be/T_mezyLhvlA](https://youtu.be/T_mezyLhvlA)

~~~
supernova87a
A question I've always had is, how is the decision on how many propellers
made? Why 16, and not 4? Or why 1?

~~~
Animats
The drone-type designs cannot autorotate like a helicopter. They don't have
the variable-pitch blade controls a helicopter does. If you lose an engine or
prop, you crash uncontrollably unless you have some spare props.

~~~
supernova87a
Ah, I see -- so the 4 prop one in the OP article... that is basically a death
trap at some point?

~~~
hengheng
It's 8 (two stacked along the same axis in each corner), so there will be some
kind of redundancy.

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neonate
[https://archive.is/lg4yx](https://archive.is/lg4yx)

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finger
Is it physically/technically possible to have quiet or silent rotors on
drones? I can’t imagine flying cars as depicted in the article becomg a thing
in cities if they sound like the 2010 FIFA World Cup.

~~~
falcolas
Not really; an airfoil that’s generating lift makes noise. The bigger the
airfoil and the slower its moving (relative to the air stream), the less noise
it creates. However, you can’t have those characteristics with this kind of
aircraft.

Multi-rotor copters like this rely on light and fast props, so that the speed
of the prop can be changed quickly. This changing of the prop’s speed creates
the tilting and rotational movements shown in the video.

~~~
musingsole
There are means:
[https://patents.google.com/patent/US20180305004A1/en?oq=2018...](https://patents.google.com/patent/US20180305004A1/en?oq=20180305004)

Blade design can also contribute or reduce noise. Fully silent while providing
sufficient lift seems impossible...but how long did it take to innovate to the
bladeless electric fan?

~~~
robkop
Isn't the bladeless electric fan just a ducted bladed fan?

~~~
slavak
No, because "ducted fan" has a very specific meaning in aerodynamics. But yes,
a bladeless electric fan isn't actually bladeless, the blades are just hidden
inside the fan body.

[https://en.wikipedia.org/wiki/Ducted_fan](https://en.wikipedia.org/wiki/Ducted_fan)

------
jackson1442
I don't see how this could ever be feasible for consumers. People still
struggle to drive when there are roads, what's going to happen when you add a
third dimension to control?

~~~
mrec
I suspect self-driving is much, much easier when you get up above ground
clutter.

~~~
sonofgod
I agree.

In two dimensions, a vehicle moving North-South and a vehicle moving East-West
have to cross into each other's path at some point, and 2.5D solutions
(bridges and flyovers) help but require significant investment in resources
that simply isn't possible at every junction.

In three dimensions, this simply isn't the case; we can separate different
directions of traffic by height, and provision of dedicated corridors for
changing route is merely a matter of making regulation rather than
infrastructure.

There's a reason why we've had autopilot on planes for significantly longer
than on cars.

~~~
falcolas
The flip side is twofold - to take advantage of said autopilot, you need a
pilot’s license, which is significantly harder and more expensive to get than
a car license.

Aircraft are also expensive (and come with expensive operating costs like
airframe examinations), since their failure mode is a more-or-less controlled
“falling out of the sky” - so you want the most resilient parts you can have
to skew more towards the “more controlled” end of the spectrum.

There’s also a whole network of human traffic controllers who work 24x7 to
accommodate our existing air traffic; more would be required.

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dak1
People are going to be dreaming of flying cars until some other technology
comes along that completely obsoletes them.

~~~
disown
Or until they hear how loud they are. People underestimate how loud these
flying cars are and how much noise pollution can ruin their quality of life. I
can't imagine a suburban neighborhood full of these loud flying cars.

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mattoxic
Can just see the kids running to the car after soccer practice and mum yelling
"BLADES!!"

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ezconnect
If multi rotor cars become standard, we will all be wearing ear protection.

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person_of_color
What we need is propulsion systems like the Tic Tac spotted by the Nimitz.

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dvh
Imagine if every one of your neighbours had one or two...

~~~
Gibbon1
It's the ultimate wonderful if you own one. Terrible when everyone else does.
It's like automobiles X 100.

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swatkat
Looks like a worthy competitor of Moller Skycar /s

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Markoff
why is the headline talking about flying car yet I don't see any wheels?

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noobermin
I can't read the article, but if it leads to widespread adoption like the
automobile was, I can see this being much worse for society than the car was.
Some examples of the sort of things we can see:

\- Suburbs times 100. Now, the suburbs would be even less accessible as they
wouldn't even be connected by roads. Coincidentally, they could be anywhere,
which would spread out utilities and make them even more inefficient as they
are now due to sprawl.

\- Much, much more expensive, both due to the complexity but due to insurance.
Already cars are deadly and destructive, flying cars would lead to all sorts
of accidents and property destruction given the difficulty of driving them
especially by non-professionals. This too would probably be normalized like
automobile destruction is but the actual cost will still exist and need to be
subsidized by sky high insurance premiums

\- Further destruction of cities. Now, like wide streets and highways that
demolished neighborhoods (often black and immigrant communities), we'd see
calls for destruction of tall buildings for "the sake of safety" due to the
common place destruction discussed earlier. Streets and walkways like
sidewalks today would fall into disrepair, trees and monuments would be cut
down or removed for safety, and so on.

Then again, I don't think we'd get that far due to climate change, but this is
just based on a historical understanding of what happened to the US since the
30's. I can see a much more atomized and disconnected society.

~~~
nwah1
Other problems:

1) Terrorism. I know you mentioned property destruction, but intentional
terrorism targeting humans is a real risk. Cars are already lethal weapons.
Terrorists have used them to mow down dozens or hundreds of people at a time.
Flying cars could become kamikaze weapons, or could be hacked into becoming
them, with far more lethal potential. 9/11 was just a bigger version of this,
so the precedent exists. Yet, there would be no TSA to protect you. Would we
need civilian air defense turrets?

2) Noise. This would be huge, because rich neighborhoods that have frequent
helicopter traffic are already flooded with complaints. If flying cars became
commonplace, the noise issue would be dramatically worse than that.

3) Light pollution. We already have an issue of light pollution that makes
stargazing and enjoying the night sky difficult. More importantly, it disrupts
sleep patterns, which has all kinds of knock-on effects for society in terms
of mental health, childhood development, accidents, and so on. Constant lights
in the sky at night would be a nuisance that even high fences wouldn't block.

4) Inequality. Those who can afford the new vehicles, which will surely start
out pricey, get to perform geo-arbitrage. They can buy cheaper land that
hasn't yet factored in the new commuting realities, and yet make the same
wages. Would be one extra hurdle for those trying to become upwardly mobile.
One more huge debt burden to take on, while striving in the rat race.

~~~
theklub
These are all already car issues. Terrorism seems to be over sold anyway.

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runawaybottle
Why not focus on building better and cheaper helicopters?

~~~
rossjudson
If my experiences with Satisfactory have taught me anything, it's that the
answer is usually more conveyor belts.

