There are lots of technical roadblocks to feasible flying cars but the cost of the potential energy to change elevation is not one of them. The optimal altitude flown would be lower for shorter trips, and when normal cars must change elevation (i.e, drive over hills/mountains), they do not use so much fuel as to make the trips infeasible.
In a flying car, much more energy is used fighting air drag and gravity drag.
Where does the column of flying cars go? Do they expand vertically or horizontally as traffic increases?
In the underpopulated area's of the US where 10% of the population lives this is a feasible mode of transit, what about the 90% that actually have traffic?
If the cars broaden vertically it's a safety risk, if the cars broaden horizontally it's a violation of property rights (and a different safety risk), if the cars don't broaden it rapidly becomes inefficient and dangerous.
Also, with the advent of KERS and other regenerative systems cars will be able to recapture the bulk of energy consumed for elevation changes. To my knowledge there's no such effective system for planes. So the efficiency on cars is still higher than air vehicles.
That's the evidence you're giving to dismiss the ability of flying cars to distribute over multiple altitude? Once we've accepted the hypothetical that technology allows for a single car to fly from A to B safely (which is almost certainly automated), it seems clear that having cars move at different altitude will be trivially possible.
> Also, with the advent of KERS and other regenerative systems cars will be able to recapture the bulk of energy consumed for elevation changes. To my knowledge there's no such effective system for planes. So the efficiency on cars is still higher than air vehicles.
No one is disputing that regular cars are more efficient than flying cars. But trucks are less efficient than container ships, and we still use the former when the latter is impossible or too slow. You said "Flying is not a valid commute solution and never will be because of physics", and this just isn't true.
"Safely" will never mean a 0% crash rate. So, when a failure occurs that causes the vehicle to crash uncontrollably the property damage and casualty level will be determined largely by the vertical density of the vehicles.
> But trucks are less efficient than container ships, and we still use the former when the latter is impossible or too slow
Two issues with this:
a) the cost difference between container ships and trucks is not so large as that of air and ground travel
b) the reason that less efficient trucks are used is exactly because there's an economic demand for delivery and it is the price/time optimal solution.
For someone with a commute that can be shortened from 90 minutes to 15 minutes and makes in excess of $250K a year this is a solution. For everyone else it doesn't make sense.
Computers and elevators aren't comparable analogies, perhaps the jetpack is?
In real world we can't accept this because there are always unpredictable factors, we can only say that probability of a safe flight in a single car is say 99.999%. Then if there are 20 cars one right above another, then probability that none of them crash is only 99.98%, and it could damage all cars below it, so the resulting probability of safe flight in a car reduces to something of order 99.99% instead of 99.999% for a single car. And 99.99% is really not safe enough for everyday flying during many years.
I've been present for 2 highways collisions, avoiding them is super easy. Which is why full lane closures and multi-car pile-ups are as infrequent as they are relative to the frequency of two car accidents.
A vehicle that falls from 100 feet above will be accelerating unlike vehicles in an accident on a highway which will rapidly decelerate.
Furthermore, you now have multiple vehicles taking evasive action based on dynamic predictions that cannot incorporate a collision. The second that one car hits another you're going to lose a chunk of your column from pachinko like bouncing.
Now, instead of a small mechanical failure you can have drastic loss of life because all of the occupants plummeted to their death.
Do you work for Uber?
As I mentioned earlier, the future we are talking about is one with self-driving cars. The fact that the vehicles are accelerating is much less of a concern than sheer number of seconds allowed for an automated system to take evasive maneuvers. (Coordinating evasion is also much easier for automated systems, and traffic collision avoidance systems are widely used in planes, but this is a secondary point https://en.wikipedia.org/wiki/Traffic_collision_avoidance_sy... )
Your anecdotal experience is not really informative. But what is informative are car and plane accident rates, and the fact that altitude separation for planes is already a standard practice for avoiding collisions.
https://en.wikipedia.org/wiki/Separation_(aeronautics)#Verti...
It is a strong contributor to the fact that mid-air collisions are much more rare than the multi-car pile-ups from having cars in adjacent lanes. As I read your logic, you would assert that planes would be better off flying parallel, all at the same altitude, so as to avoid the need for grade separation. But this is not how air traffic is managed. Yes of course planes are able to separate out further horizontally than cars can (and just as a flying car would be able to), and this reduces the risk of collision debris dropping down on top of any other random plane. But this clearly does not mean that if, for whatever reason, planes became more horizontally restricted, they would make less use of vertical space.
Edit: We've hit the end of the reply chain. I see your point about both the opening and closing sentences. Is there any way to say the first one without coming off as hostile? My goal/point was trying to demonstrate how patently wrong the earlier statements were.
The evidence or examples you provide should make that clear. Unless you have very strong irrefutable evidence, I would hesitate making any absolute statement declaring someone wrong. What does it gain you? No one likes to be told outright they're wrong. The goal shouldn't be to score points: it should be to reach common understanding.
If this is something you'd like to cultivate further, you might find the references in my profile useful. I refer to them myself regularly.
From my unsolicited, third-party perspective, two things jump out at me.
- You could do without the first sentence entirely.
- The insinuation that the parent is possibly a shill (an Uber employee)
The rest of it is fairly neutral.
You also don't need to build much infrastructure other than landing/takeoff sites. Large infrastructure alone, especially in a place like the USA is a big blocker.
That only ensures that flying cars will always be more expensive than ground cars, not that per capita income will always be too low to have mass adoption of flying cars.
True, but the economics of energy/housing/transit indicate that there never will be mass adoption if it's also the more expensive option.
That depends largely on any negative value that's charged against living in an undesirable location, and on the subjective value a person ascribes to living in a desired location. And that subjective value can remain constant, while the cost of energy and transit decrease, and the economic value created by the person increases.
Yes, it would probably be economically more efficient to live in low-cost housing projects within a few minutes walk of the offices of megacorporations. But millions of people (76% of Americans, according to this 2009 survey: http://www.census.gov/prod/2011pubs/acs-15.pdf) choose to drive an single-occupant automobile to work, averaging a 25-minute commute each way. And few would give up their acre of land and private home to live in an apartment closer to work.
If you could take a high-speed helicopter from Monterey to an office in Silicon Valley for $5 and a 15-minute flight, instead of hours of your time, or $500 in helicopter costs, would you really live in on-campus housing because it was more economically efficient? Yes, flying a helicopter for an hour takes a lot of energy: on the order of 1,000 kilowatts per hour. And yes, helicopters are really expensive and niche. But technology is constantly decreasing both the cost of that energy and the difficulty and operating expenses of flying machines.
There are two things I feel you neglect:
a) These increases happen in parallel, meaning that as air vehicles get better so too do ground vehicles. Meaning it's unlikely for the relative advantage of cars to change with technology improvements.
b) I can state the last sentence because of the physics and engineering fundamentals that go into ground and air vehicles. There are hard and fast limits to the physical world, air vehicles have to butt up against a lot more of them than ground vehicles do.
1000 kW, or 1000 kWh per h. That's the beauty of P = Power = W/t = Energy / Time.
Cost isn't a big deal when it's less than a 50% increase, we're talking 3-5x here. This is equivalent not to a Hummer but to a Ferrari, that's a difference in sale volume that makes a flying car unit unsustainable give the increased non-traditional expenses.
Which is why birds only ever fly long distances, if it's just a few miles they hop it.
For reference, a Cessna 172 flies around 110 knots = 125 miles per hour, and uses about 10 gallons per hour, so it gets about 12 mpg.
Granted, that's pretty bad, but that's about 1950's technology, and it's not orders of magnitudes.
And in 3D you have MUCH more space (in fact, one reason that there are so relatively few mid air collisions is just the fact that "the sky is big".)
So, I don't think aviation is out a priori "because physics".
In 1950 a car cost ~$1.5K in the US, GDP per capita was ~9.6K. So it was around 0.16 of GDP per Capita to purchase a new car.
In 2016 GDP per capita had risen to $53k with a new car costing between 17K and 33K depending on how you look at it. This is 0.32 to 0.62 of GDP. More, but not horrible.
A Cessna costs $160K, a 3x factor compared to GDP. So for around the price of a house (or down-payment) you can own a depreciating mechanical liability that enables you to commute marginally faster...
The economics aren't there.
For what it's worth, I don't really see personal aviation take off anytime soon anywhere near as much as personal driving has - but some niches might become feasible with personal electronic VTOL aircraft (PEVA).
And anyway, even if it cost that much, it's still a viable route for commuting using a rideshare service like Uber if you have 3-4 people sharing the same vehicle and you're shaving off 2 hours of commuting each day (500 hours extra per year at $30/hour gives you $15,000 extra per year PER PERSON).
I imagine the same applies to air commute, considering most people will be converging into a small number of waypoints.
a) you don't have to stick to airways. They're largely for ease of planning and navigation with ground-based navigation aids (NDBs, VORs). You can easily fly off airways, and (in general aviation planes during visual flight) nearly always do.
b) with the advent of GPS, "direct" flight routes (not involving airways) are becoming increasingly common.
c) The "big sky" is not a fallacy. Think about it: first, on the ground you can only drive where there are streets. In the sky, you can fly everywhere (even on a 2-D plane), plus then you have the third dimension. There is plenty of space, and congestion won't be a problem unless regulatory/technical issues impose bottlenecks. Airports are natural bottlenecks, but what is envisioned here are VTOL aircraft, so the number of suitable take off and landing places would multiply.
d) The "navigation paradox" [1] is that improved precision in navigation leads to increased risk of collision, because where in the past airplanes where only approximately on an airway (and would most likely miss each other in case of ATC mistake), now they're precisely on the airway (and will collide in case of ATC mistake), see the case of the GOL and Embraer in Brazil [2]. However, that is a shortcoming of current ATC practices, not inherent in flying.
e) I don't understand your point regarding property law. You can hop on a Cessna at Palo Alto or San Carlos airport and fly over the Golden Gate Bridge, San Francisco, Oracle, Stanford, SLAC, San Jose, with no problem. The airspace is there and it's open.
Bottom line: with modern navigation methods, air space congestion will only become a problem after personal aircraft have become tremendously popular and prevalent, if at all.
[1] https://en.m.wikipedia.org/wiki/Navigation_paradox
[2] https://en.m.wikipedia.org/wiki/Gol_Transportes_A%C3%A9reos_...
1) Cities near water bodies like SFO, NYC, Miami or even Chicago can benefit from over water flying cars. This provides some safety while making more areas livable within a short commute to downtown.
2) Places like Mumbai, Bangalore where car ownership has outpaced the governments ability to create roads causing massive traffic jams can be served by a vertical stacking approach you mentioned and leap frog the western worlds freeway model. By creating pre-defined paths in the air and having only autonomous flying cars, the governments can save money on building roads, parking etc and also provide a level of safety against rogue drivers and airspace violation
I don't agree. While there may be less impediments to putting that traffic over the waterways the challenges are still significant.
Just using NYC as an example:
A high density of bridges.
A High volume of existing commercial and passenger boat traffic.
A number of busy heliports are located along the waterways.
And although the rivers could help you navigate you up or downtown they provide no efficient means of going across town further limiting this as a viable option.
As for cities with traffic jams, expecting governments that don't get enough in taxes to improve infrastructure to solve that by expecting the citizens to pay tremendous amounts for flying cars is unreasonable.
https://www.bloomberg.com/news/articles/2016-06-09/welcome-t...
Theres a lot of R&D going on behind the scenes, it no longer a lone wolf undertaking.
Its likely all these personal air vehicle will fly-by-wire; perhaps Uber leveraging Otto's core algorithm for other uses? https://www.youtube.com/watch?v=2g6cCYoDWzM
Big money has been funneled into a number of pipe dreams before, it didn't make them practical.
There is also a German project, the e-volo.
Full disclosure: I've invested a trifling sum in the Volocopter, so I'm a believer... :-)
https://www.bloomberg.com/news/articles/2016-06-09/welcome-t...
Theres a lot of R&D going on behind the scenes, it no longer a lone wolf undertaking.
https://www.youtube.com/watch?v=2g6cCYoDWzM
Its likely all these personal air vehicle will fly-by-wire; perhaps Uber leveraging Otto's core algorithm for other uses?
Flying is not a valid commute solution and never will be because of physics. All things equal, the energy requirements to change elevation will be too great to justify adoption.
The system only becomes useful/safe if you "stack" vehicles on roadways. What happens when one has a failure and crashes?
This is either market signaling or another thing Uber will bleed money onto.