Flying Cars Are Impossible, But…..

We regularly see press releases about flying cars, promising they will appear on our roads and in our skies ‘real soon now’. But, notwithstanding working prototypes as long as 50+ years ago ‘real soon’ has yet to arrive for any of the projects.

More recently, not only have we had ‘no name’ companies boast of their flying car projects, but Airbus too has started talking up a flying car project it is apparently working on (illustrated, above).

But the biggest problems with flying cars are ones that are almost certainly incapable of solution, and the basic underlying premise is flawed – it makes no more sense to have a vehicle that can be driven and/or flown than it would to cross a horse with an eagle. The compromises necessary to create a flying car result in a strange vehicle that does neither task well.

Let’s first understand why flying cars are indeed impractical, and then consider a better alternative.

A possibly fanciful concept in the early 1930s, the ‘Ascender’.

Flying Cars – Not a New Idea

The first patent for a flying car was granted on 17 August, 1903, to Romanian inventor and aviation pioneer Trajan Vuia, in Paris.

This was exactly four months before the Wright Brothers first took to the air at Kitty Hawk. To be fair, his appellation ‘flying car’ did not mean ‘a roadworthy car that can also fly’ but rather ‘a vehicle similar to a car, but which flies through the air rather than is driven on a road’.

But right from these origins, before planes first took to the air, and less than 20 years after Karl Benz created his automobile in 1885/6, futurists were already dreaming of the ‘logical next step’. On the other hand, it is also worth noting that when Trajan Vuia first presented his ‘flying car’ concept to the distinguished Académie des Sciences in Paris in February 2003, it was rejected with the curt comment

The problem of flight with a machine which weighs more than air can not be solved and it is only a dream.

History does not record their further comments subsequent to the Wright Brothers proving them spectacularly wrong, a mere ten months later.

The next somewhat substantial mention of flying cars was made in the May 1933 edition of Modern Mechanix & Inventions Magazine that a convertible car/plane prototype had been built and flown, called the ‘Ascender’ (image above). But there are only artist illustrations, and it is thought the article may be a hoax.

While his Model T was still in full production, Henry Ford was already looking ahead, and in 1926 he came up with what he hoped might become the aeronautical equivalent – the plane for everyone, to match the car for everyone. This was the Ford Flivver, a plane with a tiny 21’9” wing span, but, alas, only a single seat, which doomed the concept from the start, and contrasted with the four or more seat capacity of the Model T.

To be fair, this wasn’t a convertible car/plane. That came later, when Henry Ford predicted in 1940, ‘Mark my word : A combination airplane and motorcar is coming. You may smile, but it will come.’

The Aerocar, in the early 1950s, got close to production, but failed to pre-sell in sufficient numbers for production to commence.

Henry Ford’s prescience was hinted at in 1946 when the Aerocar appeared on our roads – and in our skies. This impressively impractical machine failed to take off (literally as well as figuratively, at first), and only six were produced. Converting from car to plane involved a lot more than just pushing a button and then soaring majestically up from the road and into the air. The vehicle had to stop and its wings (normally towed behind in a trailer) had to be affixed.

The company obtained 250 provisional orders, but needed 500 in order for manufacturing to commence, and so closed in the mid 1950s.

At the same time, Convair were experimenting with a flying car, the ConvAirCar. Only two were built before the concept was abandoned.

Alas, Henry Ford died (in 1947) before his prediction progressed much further, but his son oversaw the creation of some scale models of flying cars in the mid 1950s, using ducted fans (and even a design for a nuclear powered car too).

In a mid 1950s press release, the company more cautiously noted ‘the day where there will be an aero-car in every garage is still some time off’.

The Present Day

The Terrafugia Transition actually looks almost graceful in the sky, but….

With improvements in every aspect of aviation and engine design, with lighter construction materials, engines with enormously improved power/weight ratios, more reliability, better navigation aids and control systems, it would seem that flying cars are becoming ever more possible and practical.

Add to that the ever longer commute distances and more clogged freeways we all suffer, and the benefit/need for them might also seem to be building.

But while it has always seemed that flying cars are ‘just around the corner’, the underlying constraints and seemingly impossible to optimize compromises remain present. If one looks at the present prototypes dispassionately, it is hard to think they are a threat to most current cars in terms of practicality on the ground, or to most planes, in the air. One of the dreams of a flying car – to soar into the air whenever one wishes, speed most of the way to one’s destination, then land and park outside the store one was driving to – remains as elusive as ever.

… on the ground it looks ungainly and ridiculous.

Sure, companies continue to talk up their flying car plans, secure investments and obtain advanced orders. Most recently, companies such as Terrafugia have developed prototypes that have met some basic proof of concept testing.

Terrafugia was formed in 2006; eleven years later, it has yet to move from prototype to production. But this slow rate of possible progress is still breathtakingly fast compared to another often cited participant in this industry. Decades earlier, Moller International first started developing its version of a flying car, and now, after more than apparently 40 years, it is still only at a stage of prototyping.

Even If There Were Flying Cars, They’d Not Be Viable

We’re not saying that building a flying car is impossible. But we are expressing doubt that building one which would appeal to more than an outlying fringe of people with special interests is almost surely impossible. Flying cars as they are generally perceived are impossible and impractical.

There are many reasons why they would never work as we might hope them to; we’ll look at just a few.

Plane Style with Wings and Propeller

The biggest problem with this type of flying car is how and where they can take off and land. Will they be like regular planes – ie, have wings, a propeller, and need a runway to take off and land on, or will they be like a helicopter – ie, have rotor blades and be able to go straight up and down? (There are also vehicles that straddle the line, requiring only a very short length of runway for taking off and landing, ie STOL – Short Take Off and Landing type craft.)

The problem, if the vehicle is to be plane-like, is what you do with the wings when not in the air, and recognizing that taking off and landing would only be possible at regular airports. You couldn’t do it in your driveway, down your neighborhood cul-de-sac, or even on the highway into town. First, in plane-mode, the wing-span would probably be 30’ or wider (the wider, the better, in general terms – a four seater Cessna 172, for example, has a 36’ wing span).

The wingspan and clearance means you need a wide clear area for taking off and landing. You’d want the width to be at least twice the wingspan and ideally three times – up to 100 ft of clear space. This compares with standard runways at airports, typically 150 ft wide. A normal vehicle lane is 10 – 12 ft wide, so we’re suggesting enough clear width as would be taken up by at least five lanes of road.

It isn’t just width. It is also length. You’ll probably need 0.2 – 0.4 miles of clear and level road to take off or land on, plus no obstacles immediately ahead or behind the runway area, either.

There aren’t many places, other than airports, that meet those requirements, are there. It surely isn’t a case of driving normally on the freeway, noticing that traffic is getting clogged, so simply pushing a button and taking to the air, all in a single graceful movement with no impact on the cars ahead, behind, or in the lanes on either side!

When you have to make a special trip/detour to an airport to take off and land, is the flying car actually convenient at all?

Helicopter Style with Rotors or Ducted Fans

The Moller Skycar 400 V/STOL craft.

So, maybe you decide to go the helicopter type vertical take-off and landing approach instead. The good news? You pretty much zero out all the bothersome space you need for a regular plane.

The bad news? Your engine needs to be twice as powerful as a regular plane type engine. And you’ve now got those rotor blades above you, which will be perhaps 35’ in diameter – similar to the wingspan of a plane. If you instead choose multiple ducted fans (probably four – one on each corner), you’ve created an even more complex vehicle and propulsion system and unavoidably still have something too wide to fit on the road as a regular vehicle (the maximum width of a regular street-legal vehicle is 8 ft).

And your fuel economy has nose-dived – you’ll be sucking up at least twice as much gas per mile and per passenger as you would in a plane. Plus, get ready for some hefty maintenance bills – you’ll probably need to replace the rotors every couple of thousand hours, and you’ll need a lot more than a 20 minute visit to the Jiffy Lube every some miles.

The good news is maybe you can have your own helipad at home, as long as your neighbors for several houses all around don’t object to the noise of your car/helicopter landing and taking off.

But where will you be able to land at the other end? You need to be well clear of obstructions – you need 35’ or more for the rotors and at least that much again for a safety zone. A landing pad represents about a 4,000 sq ft clear area. If you’re using ducted propellers, you can get by with much less free space, probably under 1,000 sq ft.

But let’s say that is a solvable problem too (and not wonder why you don’t just buy a real helicopter). More problems abound.

Licensing Restrictions and Flying Skills

You’re going to need a license to fly your flying car. Hopefully it will qualify for a moderately easy-to-obtain ‘sport license’ – but this is still enormously more difficult to qualify for than a regular car license, while massively restrictive in terms of what it allows (details here). For example, it will limit you to planes weighing no more than 1320 lbs (including fuel, passengers and cargo), and limit you to no more than one passenger. Not quite the 4,000 lb family car, with room and weight capacity for spouse, kids, dog, and a trunk load of stuff.

In addition, you’ll not be allowed to fly at night or in poor visibility, and will have to keep out of most controlled airspace (ie, you’ll not be able to use regular airports).

We all find it difficult to drive our cars in two dimensions – now think about flying in three dimensions, and instead of a nice set of tires ‘biting’ into a good road surface, think instead of bald tires in the rain or ice. Plus you’ve both a maximum speed and a minimum speed – go too fast or too slow and you’re not just risking a traffic ticket or irate drivers behind; your flying car might fail and crash. And instead of clearly marked lanes and road signs, you’ve nothing visual to show you where you are – everything is instrument based in the car.

The flying skill required is different from the skill needed to drive a car. Driving a car is almost instinctive – turn the wheel in the direction you want to travel, turn it more to make a tighter corner, push your foot down more or less to vary the speed, or change pedals and push your foot down more or less to reduce your speed. There is almost nothing to learn, but still we see, every day, people who can’t parallel park, people who can’t even angle park more or less equally between the lines of their space, people who can’t reverse, people who don’t understand how to merge onto a freeway, or the obligation to keep right except when overtaking.

Flying a plane is not instinctive at all. To take just one example, turning involves a combination of changes to the plane’s yaw, and roll while maintaining the plane’s attitude which will otherwise wish to change. Each change needs to be balanced by the other two. One control combines both attitude and roll, and a second control induces yaw, except that, with more roll, the yaw changes from being influenced by one control to being influenced by a different control. And all of this is influenced by the speed of the plane and the amount of power being delivered by the propeller (which ideally would change during the turn).

Drive your car poorly and you’ll probably not be risking your life, but fly your plane poorly, and your chances of a fatal consequence grow. Remember also that there are seldom such things as fender benders with planes. You can never fly your plane slower than its minimum speed (probably 40 – 50 mph), and you almost always are going so fast and are so high that if things go wrong, death is a likely consequence.

Oh yes – crash statistics for private planes, piloted by more skilled ‘real’ pilots with full rather than sport type licenses, suggest that crash rates are in the order of ten times higher per mile or journey for private planes than for automobiles. Some analyses suggest as much as a twenty times higher risk per journey.

One of the considerations when designing a plane rather than a car is that events which are nothing more than an inconvenience in an automobile are life threatening in a plane. Running out of gas? That’s the difference between waiting by the side of the road for someone to bring you more, and crashing who knows where. Breakdown? That’s the difference between being towed to the dealership and, again, crashing who knows where. And so on – there are very few failures in a car which are truly life threatening, whereas, in a plane, there are very few failures which are not.

Noting also that most of the vehicle crashes and fatalities can be traced to some form of driver error, and noting further the much greater difficulty in flying a plane safely compared to driving a car safely, a flying car, driven by ‘ordinary people’, is a disaster in the making.

Will a society that demands safety belts, air bags, and all manner of other protective devices, both in vehicles and on the roads they drive on, accept a mass move to flying cars that are ten to twenty times more dangerous?

But, let’s be positive. Let’s say you’ve resolved all these challenges. Well done, but there are plenty more things to consider.

The Congested Skies

What an air traffic controller currently sees and has to manage. Imagine increasing the number of planes in the air ten fold.

You might think ‘Flying is great; it is the ultimate freedom. There’s the entire sky, it could never become as congested as a single narrow freeway.’. But that’s not actually the case.

It is necessary to maintain a safe distance between planes, the same as between cars. Planes can’t stop as suddenly as cars – indeed, planes can’t stop at all – if they go slower than their ‘stall’ speed, they literally fall out of the sky, and the air is not as positive a ‘surface’ to control a vehicle’s location as a road. Add to this the greater speeds that planes fly at, and the lack of ‘lane markings’ and traffic signs like on a regular road, and separation distances are necessarily much greater.

Mandatory minimum separation is probably 500 ft vertically and two or three miles horizontally. Your flying car probably won’t go much over 10,000 ft (if at all), so while you might be able to ‘stack’ a dozen planes on top of each other vertically, the horizontal separation distance means that you can probably get less than 1,000 planes per hour along a particular route, as compared to up to 1900 vehicles per lane on a freeway.

Plus also, although you can look up and see a huge open sky, with no lanes and no markings, and in some weather conditions, you’ll see a criss-cross of contrails showing planes flying in all directions, the reality is different. Especially if there are going to start to be appreciable numbers of extra private (car)planes flying, there will be even more restrictions on the directions you can fly, and when you can ascend or descend.

Our current air traffic control system only ‘works’ (and imperfectly at that) because there are very few planes in the air, and most of them are flying predictable paths while being manually routed and coordinated by air traffic controllers. This type of traffic control could not scale to handle any appreciable number of private planes all trying to share the same space as all the current commercial jets, which would be moving at two to five times the speed, and shooting out dangerous blasts of turbulence behind their engines and wings.

So there’s every possibility that unless there is a revolution in air traffic control, you’ll simply be swapping freeway congestion for airway congestion. Except that, in the air, you can’t slow down in congested space or stop; you have to keep flying at a minimum speed, no matter what.

Cost

To summarize, a flying car will never work as well as a car, and will never work as well as a plane. The design compromises are too great. That isn’t to say flying cars are an impossibility – of course they can be built, and with sufficient money spent on addressing some of the design compromises, they might even end up being semi-satisfactory, albeit at a cost of probably $1 million and more per vehicle.

Which brings us to the last problem. Well, not the totally last problem, but the last one we’ll consider here. The cost.

It is bad enough paying $50,000 and up for a car – are you now going to pay $500,000 and up for a flying car? Are you going to pay more for your car than your house? For something that at best will only hold two people and very little shopping, and which can only fly during the day, in good weather?

At least with a ridiculously expensive car, you can pretend to yourself that you’re getting more in return – more comfortable ride, more features, more safety, whatever. With a flying car, you’d be getting much less of everything, for much more cost.

Even if you can see your way clear to the cost of the flying car, what about the ongoing maintenance costs – it isn’t like your Toyota that visits the dealership once every six months for a 30 minute oil and lube and nothing else.

More Problems

If you’d like to see a more technical discussion on some other of the problems related to designing a flying car – issues like center of gravity location – this set of seven pages lists 12 problems.

The ‘Flying Car’ Concept That Could Work

An example of the type of future vehicle that might truly become possible.

We suggest the earlier flying car concept, little changed from Henry Ford’s vision through to the present prototypes, needs to cast off its historical evolution and be redesigned anew.

The first thing we need to do is abandon the concept of a dual purpose vehicle. Let’s not try to cross a horse with an eagle. Let’s instead seek a vehicle that is fully independent of our roads. It is better to fully incorporate all the latest design and control capabilities to give us a ‘go anywhere’ vehicle that gets where it is going, completely without requiring roading at all.

So, let’s bring the design into the 21st century, and in particular, get rid of one woefully obsolete and obstructive component. The need for a human pilot. Let’s instead consider a self-piloted flying vehicle, perhaps something like the craft described in this article and illustrated above.

For our purposes, we’re talking about vehicles that will do it all themselves. You will tell the vehicle where you want to go, and they will semi-autonomously take care of all the details.

We say semi-autonomously because the vehicle will be linked in to a central computerized air traffic control system and to all other nearby vehicles. It is ridiculous that we still have people – air traffic controllers – doing a job that is simultaneously complex and demanding, but also very much a ‘by the numbers’ routine task that nowadays can be done so much better by computers.

This total 100% linked control network will have each ‘flying car’ all the time communicating with all the adjacent flying cars and a central coordination facility. Probably even the central coordination facility concept is outdated – each separate vehicle can have enough on-board intelligence to be able to perform all ‘negotiation’ with all other vehicles in the air, all in a computer chip smaller than the memory card in your camera.

This total awareness/total control will allow for a tremendous reduction in separation distances between craft, thereby increasing the traffic carrying capacity per cubic mile of sky, and eliminating the need for ‘lanes’ in the sky. Just like in a movie stunt where someone runs across ten lanes of busy freeway without getting hit, the onboard computers in each vehicle will enable complex and crossing paths to be plotted safely, and the sensor systems each craft will have (similar to what is already appearing on self-driving cars) combined with GPS and other navigation aids will ensure that each craft knows its own position and the position of all other craft to within a few inches. Best of all, not only does every craft know where all other craft are, every craft also knows what every other craft will be doing in the future, too. There will be no sudden unexpected changes of direction.

Congestion will necessarily become a thing of the past, too. This is not only because there’ll be a huge increase in how many craft can be in the air simultaneously, but also because, in a super-sophisticated version of today’s ‘ground holds’ for passenger planes, your ‘flying car’ won’t take off until it has a clear path plotted all the way to its destination.

Less congestion, faster air speeds, and more direct routes. Instead of perhaps a 15 mile 40 minute drive, you might have a 10 mile 7 minute flight. That even means less gas is burned.

Oh – there’s still more. That $1 million or more cost? Needless to say, mass production will see the price drop down to a more sensible level. But, you’ll never know what the vehicle costs, because you’ll never own it yourself. When you need to go somewhere, you’ll use an Uber type app to summon one. It will take you where you need to go, and then will go away and on to help someone else. If you only need a single-seater, that’s what you’ll get. If you need a craft with capacity for four people and some packages, you’ll get that instead. The very efficient utilization of these craft mean that the capital cost of them is spread over more hours of operation and over more people benefiting from them, so even after allowing for a fair profit to the future Uber type operators, your transportation costs will be lower than they are now. You won’t need to worry about where you’ll park your car plane, either, because when you’re not using it, it will be elsewhere, transporting other people to other places.

We expect that the type of craft will necessarily have some type of vertical or very short take off/landing capability rather than requiring runways. Runways? That’s another old-fashioned concept that might only now be occasionally seen at trans-oceanic airports. Most of the time, we’ll travel either by ‘flying car’ for short distances, or by hyperloop for longer distances.

Imagine the new potential this offers in terms of urban and city design. All the roads we’ve come to accept as essential and unavoidable now become unnecessary. Ground transportation becomes merely a recreational activity, and a novelty.

The future truly can be transformational, if we stop planning it based on the past.

A NY Post illustration alongside their article about flying taxis.

For more articles in our series about the future of transportation, please see :

Part 1 :  Our Three Previous Periods of World Transportation Leadership

Part 2 :  High Speed Rail – Our Missed Opportunity

Part 3 :  Hyperloop – the Benefit of Having Done Nothing for Too Long

Part 4 :  Is Private Car Ownership Becoming Obsolete

Part 5 :  The Totally Transformational Possibilities Offered by Hyperloop Technology