Aeromobil: Roadable aircraft • Hacker News Board

Re: Aeromobil: Roadable aircraft

#31

Post by knieveltech » Wed, Sep 25, 2013, 5:13 PM UTC

axxl wrote: post #13

mikeash wrote: post #7

I just don't get the appeal of roadable aircraft like this. Every single one I've seen is neither a particularly good airplane nor a particularly good car, and they're expensive . For the price of one, you can generally buy a better car, a better airplane, and a second better car to keep at your most frequent destination airport, and have enough money left over to rent cars at other destinations for years. I can't fi…

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…

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

Re: Aeromobil: Roadable aircraft

#32

Post by Pxtl » Wed, Sep 25, 2013, 5:16 PM UTC

johngalt wrote: post #15

Everyone builds a flying car, but I've always thought that motorcycles had more in common with light aircraft. Narrow body, low weight, high rpm engines etc... If I were designing a road/air vehicle. It would be a motorcycle with detachable wings/prop.

Google Pal-V.

Re: Aeromobil: Roadable aircraft

#33

Post by reirob » Wed, Sep 25, 2013, 5:16 PM UTC

johngalt wrote: post #15

Everyone builds a flying car, but I've always thought that motorcycles had more in common with light aircraft. Narrow body, low weight, high rpm engines etc... If I were designing a road/air vehicle. It would be a motorcycle with detachable wings/prop.

http://www.wimp.com/flyingbike/

http://www.designboom.com/technology/flying-hovercraft-bike-...

Re: Aeromobil: Roadable aircraft

#34

Post by wtvanhest » Wed, Sep 25, 2013, 5:18 PM UTC

notahacker wrote: post #29

axxl wrote: post #13

Earlier quoted context omitted.

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…

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 a…

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.

Re: Aeromobil: Roadable aircraft

#35

Post by dsr_ » Wed, Sep 25, 2013, 5:19 PM UTC

The appeal of the flying car is imaginary: what people immediately fantasize about is rolling out of their driveway, finding a clear stretch of road, and taking off.

Make that one hour commute a lovely fifteen minute flight!

But that can't actually happen. The month of driving practice needed to get a license becomes a year or more of pilot school. The damage inflicted by motor vehicle accidents is already horrendous enough without adding a thousand meters of altitude into the equation.

Re: Aeromobil: Roadable aircraft

#36

Post by mikeash » Wed, Sep 25, 2013, 5:22 PM UTC

axxl wrote: post #13

mikeash wrote: post #7

I just don't get the appeal of roadable aircraft like this. Every single one I've seen is neither a particularly good airplane nor a particularly good car, and they're expensive . For the price of one, you can generally buy a better car, a better airplane, and a second better car to keep at your most frequent destination airport, and have enough money left over to rent cars at other destinations for years. I can't fi…

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…

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".

Re: Aeromobil: Roadable aircraft

#37

Post by bathat » Wed, Sep 25, 2013, 5:28 PM UTC

axxl wrote: post #13

mikeash wrote: post #7

I just don't get the appeal of roadable aircraft like this. Every single one I've seen is neither a particularly good airplane nor a particularly good car, and they're expensive . For the price of one, you can generally buy a better car, a better airplane, and a second better car to keep at your most frequent destination airport, and have enough money left over to rent cars at other destinations for years. I can't fi…

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…

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.

Re: Aeromobil: Roadable aircraft

#38

Post by nightski » Wed, Sep 25, 2013, 5:28 PM UTC

mikeash wrote: post #24

zxcvvcxz wrote: post #14

Earlier quoted context omitted.

Does this not seem to be the pattern of most emerging technologies? They're bulky, not so practical, and expensive as hell. Would a consumer want to buy this now? Probably not. I think the site is more for the purpose of bringing people on-board to the project (engineers, investors, etc). That being said, I think it's a very exciting vision with practical application. If you're a business traveler, why bother with th…

It's also the pattern of plenty of bad ideas. How does staying in the same vehicle help? Is it really that big of a deal to move between your car and your airplane? Let's not forget that airplanes need a preflight inspection before you fly if you're not suicidal, and having just driven the airplane to the airport doesn't eliminate that need. Quite the contrary: being exposed to the stresses of driving will increase t…

Technically you are supposed to pre-inspect your car before driving every time also. Remember the DMV course taken in high school?

Also you don't need a flight plan, that is completely optional (it is essentially a SAR service if you crash). With modern avionics you can dynamically recalculate flight paths on the fly in the cockpit.

You really don't need clearances either, unless flying into class B airspace (which you don't really want to do that with a small plane anyways). You can fly across the country without ever telling anyone.

Also having separate planes and cars has real disadvantages. What about when you arrive at the destination? You always have to rent a car. Not only that you have to store the plane which can be quite expensive. There are many advantages to this.

Re: Aeromobil: Roadable aircraft

#39

Post by SuperChihuahua » Wed, Sep 25, 2013, 5:29 PM UTC

dsr_ wrote: post #35

The appeal of the flying car is imaginary: what people immediately fantasize about is rolling out of their driveway, finding a clear stretch of road, and taking off. Make that one hour commute a lovely fifteen minute flight! But that can't actually happen. The month of driving practice needed to get a license becomes a year or more of pilot school. The damage inflicted by motor vehicle accidents is already horrendous…

We just have to upgrade Google's driverless car. And the drawbacks you mention are the same drawbacks when we stopped using horses. Why do you need a dangerous car when you can use a more safe horse without a drivers license?

Re: Aeromobil: Roadable aircraft

#40

Post by nether » Wed, Sep 25, 2013, 5:32 PM UTC

mikeash wrote: post #7

I just don't get the appeal of roadable aircraft like this. Every single one I've seen is neither a particularly good airplane nor a particularly good car, and they're expensive . For the price of one, you can generally buy a better car, a better airplane, and a second better car to keep at your most frequent destination airport, and have enough money left over to rent cars at other destinations for years. I can't fi…

Your pricing data are wrong.

Terrafugia Transition, new: $279,000

Cessna 172 Skyhawk, new: $289,500

The Transition only seats two while the 172 seats four, but I'd personally rather have the plane that also drives.

http://www.terrafugia.com/aircraft/transitionR‎

http://www.cessna.com/single-engine/skyhawk