Why did anyone ever think flying cars were a good idea?

One cliched gripe is “it’s the future, where’s my flying car”. To me, I hear this as an indictment of technological progress - we humans are too stupid to have invented practical flying cars yet in 2015.

Yet, if you even try to napkin sketch any kind of car flying air vehicle with the rough mass and dimensions of a car, you instantly arise at a massive problem.

You have to send down an air stream equal to the mass * g of the vehicle. That is, the air mass * velocity must equal, dat conservation of momentum. You can send a lighter stream of air down faster but you have to pay with quadruple the energy every time you double stream velocity.

So ignoring details of implementation, no matter what, you have to have a massive wall of air coming down from the vehicle, and a tremendous amount of energy must be supplied to do this. Also, falling kills people, so a flying car can’t be passively stable - when it’s near the ground and can’t be flying forward, it must be hovering on this air stream, which means the equipment to do this must not fail.

The second issue is that in terms of energy storage, liquid fossil fuel is the best we have. Nuclear doesn’t scale. Even if we invented a relatively “lightweight”, compact fusion reactor tomorrow, something that did aneutronic fusion and was like a fancy x-ray machine and passively safe, the small percentage of neutrons produced would mean you still need massive, heavy shielding that can’t fit in a car. The minimum size of the engine alone would still be locomotive size (and weight) or bigger. This is the actual reason the Ford Nucleon would never work - ignoring the safety and cost issues, there’s no way to make the shielding fit into a car.

So you need liquid fuel, and you have to spend a certain amount of energy for the car to hover, and there you go - no way to build a flying car that doesn’t consume liquid fuel in massive quantities for takeoff and landings.

I don’t see any solution to this. It just doesn’t make any sense. It *has *to be ridiculously noisy and unsafe to nearby people on the ground (requiring special takeoff pads), guzzle expensive fuel like it’s nothing, and inherently prone to killing everyone onboard.

Much, much more practical schemes are things like PRT transport pods, hyperloop like evacuated trains, and plain old cars under computer control. All these solutions, you have the vehicles traveling down safe, friction controlled paths on roads and bridges, with computer control of vehicle movement to eliminate almost all the crashes.

Answer: the Rule of Cool.

It’s not an issue of a hypothetical - when I was in grade school in the early 90s we watched an actual, serious documentary about a flying car someone was developing and the video matter-of-factly asserted that they would be in mass production in about 10 years. I imagine many others also saw this documentary and that’s the basis for the “where’s my flying car?” thing - it was literally promised years ago that they would be a thing by now.

Surely this video (maybe there were several) must still be around somewhere.

Everybody who’s serious about flying cars agrees more or less with the OP’s POV. But they’re more of a literary device than a practical vehicle. And as literary devices they make perfect sense.

Look at the progress in computers from ENIAC to the latest supercomputers or even the latest smartphones.

Now imagine we’d made the same progress in energy conversion and energy storage density since the 1950s’ crude gas turbine engines, IC engines, and gasoline/kerosene.

Imagine that instead of fizzling, atomic power plants had improved as much as atomic weapons did. Compare Fat Man with a W76 and imagine we’d done the same to PWRs.

*That’s *where flying cars come from. Gigawatt power supplies that fit in your backpack. New physics for anti-gravity or magnetic repulsion/propulsion. Not just better propellers attached to better IC engines burning the same gasoline your grandpappy used as a boy on the farm.

Anyone who’s ever been stuck in a traffic jam probably thought that a flying car would be a great idea.

So, a helicopter? : )
Except for the takeoff pads requirement, what you’ve talked about is a helicopter.

In a way, they are flying cars. I don’t know why people would think that the flying version of cars would look like the landbound cars they were familiar with; It’s conceiving of future transportation technology in overly narrow terms, like a medieval pikeman thinking that the future of warfare was going to involve ultrasharp pikes tens of meters long.

I think LSLguy hits the nub of the answer.

Look at the improvements in flight technology in the 50 years between 1900 and 1950. It’s easy to assume in 1950 that the improvements are going to keep on coming, until by 1990 you’ll have a nuclear rocket in your garage that you can take for a quick hop to the moon. Except now we know that flight technology followed a sigmoid curve and was essentially mature by the 1950s and we’ve only been able to make incremental improvements since then.

Power sources were expected to do the same. We start with water power and horses, then get steam engines, then IC engines, and now we have nuclear power. Well, that nuclear power source is just going to improve until you have a tiny nuclear reactor in everything putting out unlimited free energy. Except it didn’t work that way, and now here in the far future of 2015 and we’re still burning petroleum as our most efficient transportation fuel.

As a pilot (fixed-wing and helicopter), I don’t wish for a flying car. I wish for an airplane or helicopter.

In addition to ‘landing pads’, you also need a lot of clear space so as to stay within the height-velocity curve on take-off and landing.

By a curious coincidence, today’s wall street journal has an article on small personal aircraft that can take off and land in relatively small areas.

As a pilot, I wish for a Jetson-mobile.

No aerodynamics, no HV or stall-spin zone of death, no air blasted at the neighbors, no noise. And no traffic.

That’s a “flying car.” Not an automobile which flies. Nor is it an aircraft.

For those interested, our own highly esteemed Exapno Mapcase, a historian by trade, has a website devoted to exactly this sort of stuff. Which has been advertised here before. He’d be honored if you’d take a look: http://www.flyingcarsandfoodpills.com/

A helicopter is not a flying car; it requires considerable skill and situational awareness to operate, can only safely land on protected pads or cleared open areas, requires almost constant maintenance, and most importantly, leaves the factory with a mission in life to kill everyone on board. The concept of a ‘flying car’–a vehicle for daily personal transportation that can be operated by anyone with a modicum of training and awareness, only requires occasional maintenance, and can take off and land on a suburban street or parking lot–is wholly different than what is required to operate a helicopter. That this concept is far more technically challenging and complex than conceived by science fiction writers and futurists is just a result of not really understanding the challenges of developing such a vehicle.

Actual fan or air jet propelled flying vehicles for personal use would contribute to so much energy usage and noise pollution that even if it were technically possible to make them operate at the same level of operator skill as an automobile (requiring extensive automation in operation such that the failure of an operator doesn’t pose a hazard to other vehicles or people on the ground) it would be massively undesirable; it would essentially like living under the flight line of a commercial airport wherever you go. An actual ‘flying car’ would require some kind of technomagical levitation and propulsion system that makes essentially zero noise, produces no exhaust, and is as reliable and failsafe as flashlight battery.

But it would be really, really cool, and also very convenient to possess a flying car, especially if you were one of the elite few who owned them. It would be even more awesome, however, to have a flying suit from which you could wisecrack your way to repelling alien invasions and out-of-control nanotechnology. You may, however, have to produce an entirely new atomic element in order to power it, so set aside a weekend and prepare to make space in the basement for a particle accelerator built form components you purchased from Amazon.com.

Stranger

That only works for the first few who have them. Once everyone has a flymobile, the traffic jam problem will be as bad as before. It just gets elevated.

As illustrated as far back as 1962 on The Jetsons. George was often stuck in traffic and got the occasional ticket from a cop on a flying cycle.

The Jetsons and similar stuff is definitely part of where flying cars came from in the popular imagination. Also, growing up in the early to mid 1960s, the year 2000 was ‘The Future’ by which time all the cool stuff we fantasized about back then would have become a reality. Hence, “It’s the year 20xx, where’s my flying car?

With all of three-space to play with, the notion that you’d have traffic jams in the sky was kinda silly. Once you don’t have to put down thick layers of asphalt to add vehicle capacity, you have as much room as you want. Even if you need to have specific corridors for flying cars to fly in, in order to keep everyone from running into everyone else, you can make the radii of those corridors as big as you need to.

(George Jetson being stuck in traffic and getting tickets had more to do with the show’s writers basically re-creating the gripes of the 20th century office worker and his family, complete with disagreeable bosses, battle-axe mothers-in-law, and that godawful music the kids are listening to these days, not to mention the aforementioned rush-hour traffic and getting traffic tickets, into a ‘futuristic’ environment.)

One problem of those planes and other small aircraft like say a Cessna 172 is they really are a tiny compact car inside, with even less comfort and even less luggage space. Sort of like an old Volkswagen with the pricetag and luggage space of a Ferrari. A couple of those in the WSJ article are just 2 seaters. Also no bathroom and no quick way to make a stop.

You think fitting an extra heavy or extra tall person into an airline seat is tough, try a small airplane.

Now getting back to the OP, I know people who have a small plane that is practically their “flying car” that they use for their business like say they are salesmen or an area manager which works out really well because usually its just them and maybe 1 other person and they can cover a large area very quickly. They just fly to a nearby airport, rent a car, and can be quickly on their way and back again.

For example years ago Sam Walton of WalMart would check his stores by the air by simply flying over them and counting cars.

EmDrive may get around lots of the issues the OP brings up, that is if it works and we can figure out how to scale up it’s power:

https://en.wikipedia.org/wiki/RF_resonant_cavity_thruster#EmDrive_2

No, see my post. The idea came from a documentary about someone who was developing a flying car that literally said they would be everywhere by now. I was just talking about this subject with a friend around my age and they remember being shown the same documentary in school, and he even remembered how they explicitly said it would be mass produced in about 10 years. Now I need to find this thing.

And, you know, rewrite the laws of physics.

Frankly, even if it does work, the EM drive supposedly exploits the expansion of the universe itself or some other extremely weak, far away phenomena. You would kind of expect it to only work if you have a massive nuclear-electric reactor as a power source, are in the vacuum of space, and have lots of time on your hands for the tiny force produced to add up.

Certainly that’s what all the credible discussions of EM drive amount to - even in their wildest dreams, no one thinks you could fly on earth with it.

Historically, a Cessna 172 cost about twice (or less) the U.S. median income. Of course Ferraris were cheaper then, too. :wink:

It’s been a long time since I’ve been in a VW Bug, but I think the analogy is pretty close. ISTM there’s more shoulder room in the Bug, though.

I take exception to your ‘mission in life to kill everyone on board’ statement. Granted, there are parts I’d look at during preflight to make sure they are good, and then think ‘Best not to think about it.’ :wink: Nevertheless, a helicopter is the closest thing to a ‘flying car’ that we have on the mass market today. Does it take a bit of training? Yes. But look at our roads today. We have personal vehicles that ‘can be operated by anyone with a modicum of training and awareness, only requires occasional maintenance’. And people crash them all the time, and neglect even the little maintenance the vehicles require to the point that they break down – sometimes catastrophically.

Good answer to the OP. The people who think flying cars are a good idea are the ones who don’t think of this. ^

It seems a simple enough problem. All someone has to do it create an antigraviton propulsion unit small enough to fit in a vehicle! :slight_smile:

Considering how many of us kill ourselves on the roads every year, I’m not sure that flying cars are a good idea, unless you can remove human error.
In fact, it would, probably, be better to not let the humans do anything at all.