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The Taylor Aerocar from the 1950s |
So it’s now 2020 and the refrain I hear from all sides—including once on these pages—is, “Where’s my flying car?” We were promised in the tabloids and the Sunday supplements that our cars would fly by now. So where are they?
But let’s think about this a bit. First, what do you mean by “car”? Second, what do you mean by “fly”?
If a car is a vehicle that takes a driver and a number of passengers and their personal luggage on a flying trip of several hundred miles, then we had such a vehicle in my childhood. The Taylor Aerocar (pictured nearby) was available in 1954. Perhaps this vehicle fell short of the “flying car” definition because it didn’t just take off from the street. The owner trailed the two wings and tail section with its pusher propeller behind the vehicle on the road and then assembled the flight and control surfaces after arriving at the airport.
For a complete flying vehicle, we’ve long had small airplanes like the Cessna 172 Skyhawk, which can carry four people and their baggage about 736 miles at a top speed of 143 miles per hour. That’s a convenient flying distance and time, but the plane has to start and stop the trip at an airport or prepared landing strip.1 Also, the pilot needs a course of special instruction, must be licensed, and has to file a flight plan before each trip.
Both vehicles can actually fly, but neither can park in your driveway, roll into the street, and take off from there without FAA authorization and clearance.
As to the question of flight, a hovercraft would technically qualify as “flying,” although it seldom gets more than a few inches to a foot off the ground surface. So while you can travel with this vehicle across country and even over smooth water, the dream of taking your flying car up into the air, well above traffic, and over the rooftops cannot be satisfied with a hovercraft.
No, when we think of a “flying car,” we mean the sort of compact, wingless vehicle we all saw in movies like Blade Runner or The Fifth Element. There the cars occasionally might touch down and roll along the ground, but they mostly lift into the air and fly over and between buildings. We want our everyday parkable sedan but, you know … flying.
I have seen several designs and claimed pre-production models of such vehicles. Most use some assortment of ducted fans to generate lift and then, once aloft, forward motion. The ubiquitous aerial drone2 is a model for this sort of propulsion, using computers for control of its four to six rotors in maintaining stability and direction. Having a computer keep a flying car in level flight would go a long way toward removing one of the barriers to this concept, that of requiring the driver to maintain the vehicle in level flight and control it through all maneuvers and under all conditions of wind and turbulence, the way the pilot of a fixed-wing aircraft must constantly monitor the flight envelope. An extension of this computer control would allow the proposed flying car to maintain altitude separation, avoid collisions, and make protected takeoffs and soft, on-target landings. Indeed, the pilot/driver would only have to pick a destination and route, then sit back and become an interested observer of the passing countryside.
But the block to these cars becoming practical has more to do with energy than aerodynamics. It takes more energy to lift a body and maintain it aloft with a directed airstream like a ducted fan than to propel it forward through the air using an airfoil or wing to provide the passive lift. Even a helicopter provides its lift with an airfoil: those large rotor blades, which are so unwieldy in a parking lot. But small-diameter fans of the sort lifting any flying car we can envision will provide much less lift and so require more power.
Right now, four small but powerful gas engines driving the fans would consume about four times the fuel of an old-style Aerocar. And they would weigh more than the car’s performance parameters would probably allow.3 Electric motors would be far more efficient and infinitely more controllable, as well as quieter, but the battery weight and performance would again be outside the vehicle’s desired parameters. A flying car powered by internal combustion or electricity might have enough fuel capacity or battery charge to take you to the grocery store and back at low altitude, but it wouldn’t be much more than a rich man’s toy, like the very first automobiles: more trouble than they’re worth and bought only for the excitement and display value. Such a car would not be able to take you to the mountains or to Las Vegas and back for the weekend.
This is not to say that flying cars are impossible dreams, or that their development and practical use is more than a century in the future, if they are possible at all. But like so many other technologies we see in the movies, they wait upon developments in basic physics and in energy production, storage, and release that are still years away—even though some of our best academic minds, backyard inventors, and dreamers are working on the problem all the time.
In the meantime, as the link above shows, somebody’s got a working Aerocar for sale. All you need is a trailer.
1. And we won’t get into the questions of initial cost, regular service and maintenance, special storage requirements, and inspection intervals—all of which are much more intensive than for a regular family vehicle that would qualify as a “car.”
2. The lightweight kind with four small propellers and a camera on board, not an unmanned aerial vehicle (UAV) like the MQ-9 Reaper, which observes our enemies remotely and then rains missiles down on their heads.
3. Not to mention quadrupling service costs and time.