The rolling resistance of a typical car is 0.01 to 0.015 [1], so the effective lift/drag ratio of a car's suspension is about 70 to 100, for just the wheels themselves. Missing from this number are the parasitic losses of all other unsprung mass, aerodynamic drag, and the costs incurred by traveling along roads which are neither level nor straight routes between your start and your end.
Small aircraft have L/D of 10-20 [2], and electric craft will probably fare slightly better if anything because of packaging advantages vs big ICEs.
I might do a more in depth analysis later and write up a Medium post, but my point is: Even just looking at the rolling resistance of the car and the whole L/D of aircraft, the difference is only an order of magnitude. Rolling resistance is one of the smallest contributions to drag in a car, so all up electric cars are probably only 3-6x more efficient than electric aircraft, and combustion cars are probably have a far smaller advantage.
[1]: https://en.wikipedia.org/wiki/Rolling_resistance#Rolling_res...
[2]: https://en.wikipedia.org/wiki/Lift-to-drag_ratio#Examples
The new DEP designs will do better, but exceeding 10:1 seems unlikely
The energy density of batteries is far worse than gasoline. Also, after you burn gasoline, you don't have to carry it anymore, which isn't true for batteries.
Also consider that for a plane, running out of gas can be fatal, so you can't actually use all the range. There needs to be a safety margin.
And then, consider that a practical flying car can't actually take off or land like a plane, and probably can't have the wingspan of a plane, so you might want to compare to a helicopter instead.
Current solutions can be airborne at maximum 15 minutes considering that FAA and other agencies require 20 minutes reserve you do the math.
The Zee.aero patent design as been abandoned because they couldn't scale it to fit a passenger inside.
If he means "VTOL Cessna with really good avionics" it's still a tall order but perhaps within the realm of "eventually possible given great determination and unlimited money" instead of "laugh him out of town."
As a proxy you have Icon A5 it was target at a price point of $130k in 2008 currently it's priced around $240k and only a handful have been delivered.
You will get a 25 minute around 30 miles ride with 20 minute reserve
Another optin is turbine like the AirMule, but will be hard to use it for civilian operations the hourly cost is brutal and noise and heat is really annoying for nearby people and even passengers.
http://www.dailymail.co.uk/news/article-2123200/The-ultimate...
Just add an airfoil envelope with enough of something lighter than air(heated air, helium, w/e) to offset the weight until a decent performance point is met. The heat from the engines running could help heat the gas for added efficiency.
Hybrid airships are already being marketed by Lockheed Martin so this isn't revolutionary at all.
Batteries are the heavy bit, and in my opinion, the future there is to have batteries capable of 2 minutes of flying, and a gasoline engine as a hybrid generator.
(3) With sufficient thrust, cars fly just fine. However, this is
not necessarily a good idea. It is hard to be sure where they
are going to land, and it could be dangerous sitting under them
as they fly overhead.There's probably a market for a vertical-takeoff vehicle serving a premium/luxury transportation niche - the same segment that is currently served by helicopters. I imagine you would still need a pilot's license and have to adhere to the rigorous FAA-maintenance schedule - so it would never be a mass-market product.
Which means:
1. wait for tesla like autonomous software that works for cars - we have for planes but this is a bit different 2. either high density batteries for electrical engines or very light weight ICE engines ( biodiesel or bio ethanol ) to be mass produced
- Opens up a lot of potential living space which is geographically close, but not practically connected via transit arteries
- Opens up living space in areas which are not passable by cars either because of terrain or in-tact wilderness (e.g. an off the grid home on a nearby mountain)
Both would no doubt mostly benefit the rich, but well, nobody's shocked that this is where that's targeted.
If you have some sort of a mobile house factory that will utilize local materials and 3D print the rest you really only need to worry about a few materials that can't be locally sourced.
Yes this is far away but about as far as flying cars.
Heck In 2 decades you might order a house on amazon a blip will come and set it down some roomba style bots will come out and finish it and you'll jump into your flying car and move in.
When you can 3D print almost anything including your food and produce electricity locally via wind and solar you can now live in the middle of nowhere Alaska without much infrastructure.
The SF-Alameda-Oakland ferry is already 30 minutes :).
The SF ferry is also slower than driving with no traffic or bart :)
Small aircraft are already not a whole lot more sophisticated than a production car - and often less so. But nonetheless they're still an order of magnitude more expensive.
The noise problem you brought up apropos of nothing.
You're responding to a comment responding to a comment that had concerns that were already addressed by the article, to let me know your concerns weren't addressed by the article. Surely there's a better place in the comment hierarchy for this? You'll get ignored down here.
We definitely need for example a faster way to transport rich people than cars, but cheaper than planes in short distances.
We definitely need a better way to transport patients between hospitals than ambulances and helicopters.
We need to see the future here, not the past (the outdated idea of 'flying cars')
Q: Someone is building flying cars.
A: Do we really need them?
Q: Someone is investing money into extending human life.
A: Let's talk about the social implications of immortality.
Q: Innovation announced! A: Not possible based on my legacy experience/guild qualification.
- Straight line transportation, saving energy & time
- Faster speedwise
- No infrastructure needed, software is basically infrastructure
- Can handle rough terrain with less maintenance
- Can deal with traffic better or have more concurrent bandwidth.
- Can allow cities to de-concentrate and people to live further away. Our model at the moment is the city model where everyone needs to live in population centers to work well.
- Less time wasted in lifts if the car is parked on the terrace.
- Less need of properties to be adjacent to roads or the cost basis of new developments to be cheaper.
- No driving needed, simplistic autopilot can work.
- No bridges needed to cross water bodies.
I would argue there's no need to ask if people want or need it, it's one of those things everyone has dreamt with lust about at some stage or another.
Air transport will need management for safety reasons, which means air corridors, landing areas, some kind of ATC system. Which correlates to infrastructure costs, not so straight line transportation and not so time efficient commutes.
As activity centers tends to be somewhat concentrated, huge amount of flying cars will tend to go or left small areas at the same time, creating air traffic jams to land or take off.
Classic infrastructure will still be needed to transport heavy items, such as large quantities of food, machinery, etc. Even the construction phase a new developments will need those roads and bridges.
Strangely, faster transportation doesn't mean shorter commutes, quite the contrary, the average commute time tends to go way up when transports evolve to become faster and denser as it enables urban areas to grow even more. The real alternative is to "de-concentrate" activity centers to have relatively autonomous parcels with residential, work and commerce close together and necessitating only light transport forms (by foot, by bike, or light transports like tramways).
Flying cars are also mostly "fail catastrophically systems", it's good that motors are redundant, but there are not the only items that can fail. Batteries, the control surfaces, the inboard computer, or the whole structure can fail. Flying is also quite hard, specially in difficult meteorological conditions, building automation to handle such cases will be extremely hard (I've no competences in the area but the picture of a vertical landing in windy condition, seems a bit frightening).
Interesting statistic: on a per journey basis, airplanes have 2 to 3 times more death than cars, (on a per km basis it's very safe), imagine what it would looks like with a lot of small commutes.
I'm not convinced it's really the solution... I see it at best as a cheaper and more accessible helicopter ride.
Roads are quite straight over long distances, and planes don't fly in straight lines if there's something in the way (eg a storm). I wonder if there'd really be that much difference on a journey longer than a few hundred miles.
Would be a real blessing for vanishing amphibians, hedgehogs, snakes, endemic terrestrial crabs, big cats... On the other part could be a problem for birds, bats and flying insects also, of course. And will boost the feral cat problem.
For good or worse, from a environmental point of view would be a real game changer.
Convenience and flexibility always seem to win in the end.
San Jose -> SF is the example in the article that Uber gave.
I've always imagined micro airports. They'd be like train stations. Need to get from Irvine, CA to Pasadena, CA in 20 minutes?
With this approach the flight paths could be deterministic and the cars could be reused all the time.
These are all symptoms of a badly designed city. What a place like this needs is better infrastructure, especially public infrastructure such as bike lanes, buses, and trains so that a lot of that traffic isn't necessary. Getting more people into cars will only create more problems. All you're doing is moving that traffic and congestion into the sky. If you said we needed an airbus, I'd point you to my friend who is named "airplane".
There's also a lot more sky up there than there is land down here.
Agree. Not every improvement in technology is actual progress. Let's skip flying cars and wait for teleportation.
- Solve traffic
- Live in Santa Cruz, commute to SF
- Buy a mansion in Modesto, commute to Palo Alto
- The views!
These will be VTOL, electric, autonomous air taxis, not road-drivable cars.
Obviously, these will be blocked by swarms of flying cars.
It could work in that scenario... My biggest thought for drones, is it won't work from the distribution centers, simply because they are too far out from a lot of the drop off locations.. but combined with trucks, you could have the trucks drive less in-out, and drones for drop off. Would need a handler in addition to a driver though, depending on automation capability.
This would also need to be supplemented with uber-like service for deliveries that don't fit well for drone drops.
Or we could be more ecologically and energy conscious...
Or something called a "speed limit"?
Can't believe this is the top comment on HN. Reddit? Sure, but I expect better here...
It's not about space ...it's about congested roads. Dedicated rail (or tubes for high speed over long distance being the exception) for mass transit is not the way to think about our improving our cities anymore. There will be a hardware - and software - solution.
Bad existing public transportation doesn't mean that all public transportation will be bad.
Opening a new dimension will be like switching from a horse to a first Ford car - day and night in terms of speed. Practically no more traffic jams because you can always travel at higher/lower travel channels.
> They are probably less efficient because you have to overcome gravity
Yes but eventually it might get narrow. At least you wont be stuck in traffic burning gas but constantly moving.
> they are probably going to be pretty noisy
If you plan a picnic on a silver cloud 10k feet above the ground then yes. For majority of people living in cities on the ground, it won't. I can imagine first flying cars will be very noisy just like first cars were pollution monsters... but let the Government impose fines and never-ending restrictions that will make sure car makers invest large chunks into quieting them down.
> falling out of the sky and smashing into the ground is a new failure mode
First and foremost, the only way you will fly in a car when it is 100% autonomous. There will never be a car that you can control manually. Perhaps only military/LEOs/etc, but for us civilians it won't do. Most likely by the time they fly above your heads - 10-15 years from now? most street cars will be automatic as well.
You will never own the car by the way. You won't be able to make any modifications etc. You will pay equivalent to your current car payment but you will only rent (good thing is you can always get new model without hassle of selling your old one).
In terms of smashing, I bet the first design to fly human will be made with airbags covering the whole thing, similar to the recent rover flying to the Mars. By the time you "smash" to the ground, you will be one huge bouncing ball of air.
Flying cars will move us into another lap of human evolution! No doubt about it.
Flying cars are certainly a nice gadget, but do we really need or want them? I can only think of two good arguments for flying cars, entering the third dimension if we run out of space on the surface and maybe being able to get rid of our current infrastructure, i.e. no longer having to build and maintain roads and railroad tracks and the accompanying infrastructure.
In metropolitan areas it certainly looks a bit like we are running out of space on the surface but I am actually not sure that we are not just pretty bad at making use of the available space. No longer having to maintain a large piece of infrastructure seems actually the more convincing argument to me.