One of the regular features at The Speculist during its inauguration was Phil’s “Seven Questions” interview. Phil’s last question was always “Why is it that in the year 2003 I still don’t have a flying car? When do you think I’ll be able to get one?”
Phil was asking the question metaphorically (when I answered I wrote about how large scale tech has been trailing small tech for the last thirty years). But really. It’s 2005 and we still don’t have flying cars. What gives? When Phil asked Aubrey de Grey, he got a more direct answer:
You don’t have [a flying car] because it’s very hard to build something that fits the bill — fast, safe, affordable. “Safe” is probably the hardest.
Of course, when I think of a “flying car” I imagine something like this:
But it doesn’t look like we’re going to get a gravity-defying roadster anytime soon. For now, this flying car will remain a “past-futures” fantasy. But why can’t we have an intermediate vehicle – a “fast, safe, and affordable” aircraft; an everyday, everyman aircraft?
Safety is a big part of this problem. A “safe” aircraft is “idiot-proof.” Most adults of average intelligence can be taught to be reasonably safe behind the wheel of a car. The flying car has to be comparably safe or it will never be adopted.
In order to be safe today, a pilot must be smart, fly constantly, have an understanding of his aircraft, a respect for the weather, and be humble about his skill. Many pilots don’t measure up to this, let alone the average “Joe.”
The answer is a push-button aircraft. You command it to “take me to Hot Springs, Arkansas” and it would file a flight plan, communicate with air traffic control, take off, fly, and land at your destination without interference from the pilot. Obviously this would require a sophisticated computer and software.
Assuming that could be accomplished in the short run, there is another obstacle to the everyday, everyman aircraft. Present-day aircraft are often more trouble than they’re worth, especially for short trips. Even people who have spent $100,000 + for a private plane often find that they don’t use them enough to justify the expense. Every flight requires a trip to an out-of-the-way airport and arrangements for ground transportation at the destination. Airports are put in out of the way places because they take up so much land.
If airplanes were made simple enough so that more people flew, and the amount of land required for a runway were reduced, then there would be more airports, making it more likely that an airport would be at or near your desired destination. Heliports don’t take up significant space – a good flat roof fits the bill. But helicopters are difficult to operate, and, even if a fully automated helicopter were developed, it would still require constant, expensive maintenance.
And the helicopter still wouldn’t be as safe as a fixed wing aircraft. There is a certain altitude range for helicopters called the “dead man zone.” If you lose your engine in this zone then there is insufficient time for the formerly powered rotor to be switched to auto-rotate mode. You drop like a rock to the ground.
Carter Aviation Technologies is developing a hybrid solution to these problems. Their “Cartercopter” allows vertical take off and landing, will fly as fast as a fixed wing aircraft (which is much faster than a helicopter), and will not be subject to the “dead man zone” problem. Why no “dead man zone?” Because as a gyroplane it is always in auto-rotate mode. If you lose power you just float down. Theoretically it would be safer than either a helicopter or an airplane in a power-off emergency landing.
There’s nothing new about gyroplanes. They’ve been around since 1923. But this form of aircraft has been neglected since the helicopter became practical. Carter Aviation saw an opportunity to innovate.
The Cartercopter’s first innovation is depleted uranium on the tips of the overhead rotor. Depleted uranium makes the tips of the rotor very heavy. While safely on the ground the overhead rotor is powered up by the engine. A gyroplane rotor is never powered in the air because it lacks a rear-stabilizing rotor like a helicopter. But once the Cartercopter’s rotor is spinning, the heavy tipped blade will maintain its spin and provide significant lift before the aircraft even begins its roll forward.
Second, the aircraft has wings like what you would expect on a fast moving jet. These wings are small and thin to hold down drag, but small wings provide limited lift. Without the rotor, the aircraft would stall at about 150 knots – the rotor makes up the difference.
At cruising altitude, the CarterCopter’s third innovation becomes available. Overhead rotor drag makes traditional gyroplanes very slow. The drag of the rotor is a cube function of the speed of the rotor. And the faster a traditional gyroplane flys, the faster the overhead rotor turns creating increasing drag. But the Cartercopter slows the rotor speed as airspeed increases. By slowing the overhead rotor from about 300 rpm to 100, the drag on the Cartercopter is significantly reduced which allows speeds comparable to fixed wing aircraft.
You might be wondering why they don’t just stop the rotor if drag would be reduced. Stopping the rotor would reduce drag, but it would be costly to engineer a stopped rotor, and the aircraft is safer with the rotor still spinning. This slowed rotation appears to be a smart compromise.
If a flying Delorean is out of the question, a fully automated Cartercopter would be a nice consolation prize.
UPDATE: Here’s a link to the video page at Discovery.com where you can see the program that inspired this post.
UPDATE II: And here’s a link to a 60 minutes print story on “flying cars” that also mentions the Cartercopter.
UPDATE III: In the comments Jim Strickland points out two additional problems with “flying cars” – noise pollution and petroleum depletion. To that I would add increased fossil fuel emissions.
Hydrogen fuel cells could address all of these problems. Hydrogen fuel cell vehicles run on electricity produced by hydrogen. It would be very quiet, would not deplete petroleum reserves, and would be clean for the environment.
Honda has done some impressive work in the last few years improving power output of fuel cell vehicles (see here and here). Whether fuel cells have been developed to the point that they could power an aircraft is another question. Probably not…yet.