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Comment by axxl | Hacker News Reader

That's a little bit like saying 10 years ago that no one needs a smartphone, it's a crappy phone and a crappy computer, it's too big and heavy and expensive and you can't get data anywhere and it sucks to type on. Just buy a phone for moving around and a computer for getting work done.

Things change. Anything could be the Apple Newton of the next big thing :). (Although to be honest, I see transportation moving much more to a computer controlled system rather than this, but just for the sake of argument).

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Unlike smartphones, the technology to build flying cars has existed for decades, and it's fundamental laws of physics rather than Moore's law that the designers have to combat to try to give them better performance characteristics than a WWI aircraft.

If you've already lost the time saved by not switching from car to aircraft a minute or two into the flight it's not that practical except in situations where there's absolutely no chance of getting a taxi or hire vehicle at the end. Suffice to say it isn't going to be a cheap solution to that relatively rare problem.

I agree with the general premise that flying cars are not a good idea in the near future, but I strongly disagree with your point.

1st) "fundamental laws of physics rather than moore's law" is a great analogy since people over time have continually cited physics as what will stop Moore's law. Some argue that it has in recent years done just that.

2nd) Like smartphones, the technology to build flying cars has evolved and will continue to evolve. I'm not an expert on aircraft or cars, but I can think of some areas that will make this easier right away. A) by moving all controls to fly/drive by wire, we can reduce weight, B) Materials technology has improved dramtically. C) Battery technology has improved. Maybe not for flying, but for systems. D) Weight can be further reduced by having all controls in one small computer which will eventually be the size of a smart phone instead of the size of a desktop, E) Fuel economy is improving in both cars and airplanes.

But... Here is what I think can really make it happen, and what will make it happen. When cars and planes can both fly themselves with full automatition from point to point without pilot intervention, we will see flying cars. The reason stems from the fundamental problem that 99% of people don't know how to fly, and of those that do, only a small percentage can fly, afford and want to own a car/plane.

I don't know anyone who wouldn't be interested in hoping in a fully automated vehicle which would fly them from point to point at 500 mph. You could work 250 miles away from where you live.

It will happen, just not for a long time.

The problem is that the limitation is physics, not engineering. There is little overlap between what characteristics make a good airplane and what make a good car. Additionally, many of the characteristics that make a good [airplane|car] directly work against your efforts to make a good [car|airplane].

Let me give you some concrete examples: You want an airplane to be light, have good impact protection from the front (because airplanes very rarely get run into by a mountain from behind), and not require long runways. A car, on the other hand, must have good impact protection from all sides, fit inside a lane on the road, and good acceleration so you can merge onto the freeway.

The second car requirement and last airplane requirement together necessitate folding wings, which are heavier than fixed wings (and also more complicated and more expensive). Short of a powered-lift design (which is going to be even more insanely expensive), there is no other way around the physics. It doesn't matter how good your engineers are. Physics puts limits on what you can do with a wing.

The side and rear impact protection on a car do nothing beneficial to the airplane, but add weight. Again, clever engineering can only do so much within the limits of physics with regard to material strength. I don't care if you use the most expensive quantum-dot-infused titanium-nanotubes: Real-world materials have strength limits.

As part of making an airplane light, you're probably going to want to put a small, air-cooled engine in it (the Rotax 912, used in the linked aircar, produces between about 90 and 110 HP, depending on the variant). Even a light car is going to have very poor acceleration with that engine. Again, this is a matter of physics: F=ma. Some sort of continuously-variable transmission will help a bit, but you still only have 110 HP to work with.

Smartphones have improved radically over the past 10 years because the problem was not physics, but rather engineering. Software engineers made better software (which is really what made the iPhone different from Blackberries when it was introduced) and hardware engineers made better CPUs to run the software at a decent speed.

All of these criticisms are still true of smartphones with the exception of the data thing.

There's a critical difference between smartphones and planes, which is that a smartphone is better than a computer and a phone in some ways. It's more portable than a computer, which means you can use it in situations where neither a phone nor a computer will work, because the phone doesn't have the necessary functions and the computer is too big.

There is, I would argue, no situation where a roadable airplane is better than a normal airplane plus a car. It doesn't have to be better than both in all cases, but it has to be better than both for something.

For a smartphone, that "something" is extreme portability while still providing some computer functionality. A phone+computer doesn't let you reasonably read your e-mail while standing on a bun, for example.

I've yet to see any similar case for "flying cars".

Look through the pre-iPhone pre-3G "smartphones" and the number of years they were in production to from the late 90s onward

http://en.wikipedia.org/wiki/Smartphone#History

They were shitty "computers" and very expensive phones. People had been predicting that they would happen for the longest time, and until the iPhone it pretty much seemed like nothing more than a geek dream.

Regarding the roadable car - I can imagine a fantastic use-case for commuters [on okay-weather days]. Let's say you want to live 100 miles from Boston or SF but would be looking at a brutal morning commute. But if some future-model was safe/fast/efficient/less expensive and there was infrastructure to land, all of a sudden you have a real use case.

Now the one in this video looks positively dangerous. But it doesn't mean down the road there can't be one that flies completely autonomously in most weather and can land on short runways in convenient locations in the middle of a city - that you can just drive off into a parking spot. Maybe it starts by costing as much as a tesla roadster.

I don't imagine any of this will actually happen, but if somebody can get you a roadable airplane for $100,000 that flies itself, it becomes a lot more interesting.

How is your 100-mile use case any better with a roadable airplane than with a separate car and airplane?

> They were shitty "computers" and very expensive phones. People had been predicting that they would happen for the longest time, and until the iPhone it pretty much seemed like nothing more than a geek dream.

But phones were getting smaller, and more featureful year after year so it made sense to make that prediction.

No similar trend exists in planes/cars that I know of.

There actually is a similar trend in cars. They're getting more featureful and larger. Which of course means they're trending ever further away from being able to double as practical aircraft.

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