Flying Car Part 2

As a follow-up to my previous entry about flying cars, I’d like to take a little time to point out where, I believe, this technology has a future, and where it doesn’t.

Flying Without a License

The first observation I’d like to make pertains to the popular concept of air travel for the masses. There seems to be a lot of hype about the idea of self-controlled aircraft that fly themselves from point A to point B using GPS or whatever, all without the aid of a qualified pilot. The tagline for this technology seems to be: “Getting a pilot’s license is hard. Fly our plane and you won’t need one.”

Well, the concept looks good on paper… at lest to some. But imagine, for a moment, a freeway system where a good number of the cars don’t have capable drivers behind the wheel. In fact, they don’t even have driver seats, steering wheels, or brake pedals. See, technology is great, but technology can fail. When it works, there’s nothing to worry about, but when it breaks, you want to have someone qualified to take over.

Getting a pilot’s license takes a lot of training, but all but a few hours of it is dedicated to teaching you how to get out of situations that might otherwise get you dead. There’s instruction about engine-loss, in-flight fires, severe weather, collision avoidance, and a good many other critical topics.

In fact, the pilots of the more advanced aircraft do the least work but have the most training. You’d be hard pressed to find a jet without an autopilot (and if you found one, you probably couldn’t legally do much with it). They’re not there to fly the plane. The plane flies itself. They’re there to take control when things go wrong. And considering the sort of things some of these pilots have pulled off in an emergency, I’m glad that they’re there. Truth is, flying will always require a license. Not only for the safety of the occupants of the craft, but for the rest of us on the ground, too.

Also, personal aircraft will never gain the same popularity as automobiles. Getting your pilot’s license is quite a bit more difficult than a driver’s license. While driving standards have been adjusted to place a driver’s license well within the reach of even the least capable drivers in America, pilot standards are based on safety, not economics. And despite whatever propaganda you might have read, this isn’t a step you’d be able to skip. (It’s true that you don’t need a license to fly an ultralight…. but you can’t fly it around the city or at any significant altitude.)

Vehicles of the Future

The allure of a “flying car” is unparalleled convenience: door-to-door high-speed travel, never waiting at a security scan again, and best of all, no more traffic jams.

There are a couple of different details to consider when coming up with the flying car of the future. First of all, a vehicle that looks like a car does not fly very well. Sure, you can get it off the ground, but it wont be nearly as safe or efficient as it could otherwise be. Also, it’s important that the vehicle be safe (with or without the engines). And while airframe parachutes are great, their track record is less than perfect; in other words, the craft better be able to glide safely to the ground should things go awful. The vehicle should be reasonably efficient: you shouldn’t need 700hp worth of engine capacity to lift a two-passenger vehicle. Finally, it needs to be relatively simple. Every aircraft owner knows that the more parts you add, the more expensive the thing becomes to maintain–and that goes double for engines. Everything that flies needs to be maintained to a standard unheard of with road vehicles. The cost of doing so is directly proportional to the complexity of the craft.

Existing designs

Here are some of the points regarding existing designs that are commonly considered in this particular pursuit:

Airplanes

Aircraft with fixed wings (normal airplanes) are by far the fastest, but require a whole lot of ground space to take off and land. The whole concept of an airport is built around the need for a large area for planes to safely leave and return to earth.

All else being equal, airplanes are usually simpler craft that respond to mechanical failures fairly gracefully (i.e. safely).

Helicopters

Helicopters are quite the opposite of airplanes. They operate very well at low speed, takeoff and land vertically, and can never fly very fast. Helicopters are astoundingly complicated machines requiring extra vigilant care and maintenance. An engine loss in a helicopter doesn’t necessarily lead to a crash, but it does require a direct return to earth following nearly the shortest possible path, which can be unnerving for all involved.

Autogyros (Gyroplanes)

Autogyros, or gyroplanes (which, by the way, predate the helicopter by more than 10 years, not the other way around), are lifted by a rotor much like a helicopter, but use their forward motion to spin the rotor. This principle, called autorotation, is also what allows helicopters to safely land without an engine. Gyroplanes can’t hover, but can take off and land in a very short distance–often within the length of the average driveway. “Jump” takeoffs (i.e. zero roll) are possible with many modern gyroplanes, but can be fairly tricky to execute.

The average autogyro is substantially more efficient than a helicopter, but not nearly as efficient as an airplane. The utility of this type of aircraft is severely limited; and it has therefore generally only been used by hobbyists and for special missions (like wildlife observation or cattle herding). When operated properly, an autogyro is exceptionally safe; however, it is subject to a number of pilot-induced situations that can be unrecoverable. Proper training is essential for safe operation, but because of the craft’s simplicity, proper training is astoundingly rare. As such, the autogyro has often undeservedly gotten a bad reputation for safety.

Because autogyros don’t require an airport to operate, and because they’re much more simple and efficient than helicopters, this aircraft type is an ideal candidate for our flying car concept, provided the vehicle desired is for short trips where a 100 mph top speed is acceptable.

The world of autogyros stagnated for a good many years after helicopters became popular. Research and development has picked up in recent years, however, once it was realized that (a) helicopters will always be absurdly expensive, and (b) gyroplanes can do what we frequently use helicopters for. The world of personal point-to-point aviation (i.e. flying cars) is of particular interest to the autogyro community, as they see themselves as the best match for the purpose.

VTOL Airplanes

Since conventional airplanes are so fast, many attempts have been made to overcome their glaring weakness (the required takeoff and landing run). So far, all solutions, with one notable exception, have involved simply getting enough horsepower into the craft to drive it straight into the air. This method is effective, but immensely expensive.

The exception was to create an airplane-gyroplane hybrid. Such a craft uses a rotor for low-speed operations, but uses wings at high speed. There have been a number of craft in history to employ this technique. Most notably (and recently), the CarterCopter has been employing this tactic, while at the same time working to safely slow the rotor to reduce drag during high-speed flight. In general, a airplane-rotorcraft hybrid can’t go as fast as a normal airplane. Jay Carter’s company is working to change that.

Goals

There are two basic approaches to finding the “Flying Car” holy grail. The first is an attempt to create an aircraft that you can drive on the road. The other is an attempt to make an aircraft that will take you from doorstep to doorstep, so that you don’t need a car.

Without going too deep into specific designs, I’ll explain the basic methods people are using to try to reach these goals.

Automobile with Airplane Components

When you think of a “flying car,” this is usually the image that comes to mind: an unassuming sort of automobile that allows for the attachment of specialized hardware to allow it to fly. Some of the earliest flying car designs followed this technique, it being one of the most intuitive solutions. The Aerocar (mentioned in Part 1) followed this design, as did the infamous getaway car in the James Bond movie, The Man with the Golden Gun. The Aerocar 2000 project seems to be an attempt at picking up where Molt Taylor left off–we’ll see if that gets anywhere. It’s also quite popular to make some attempt at integrating the wings and other flying matter into the car itself, so as to not have to leave your wings at home. Doing so is a bit of a challenge, so seeing different solutions is really quite intriguing. The automobile-airplane hybrid is so common a technique that no design really sticks out in the crowd. The size of the crowd, however, is a marvel in itself.

Powered Lift

“Powered Lift” is the official FAA terminology for an aircraft that can “power” itself into the air by directing its thrust downward. Aircraft in this category include the tiltrotor V-22 Osprey and it’s smaller cousin the Bell 609, along with V/STOL fighter jets like the Harrier and the Navy configuration of the Joint Strike Fighter.

Moller’s Skycar is the only (as far as I know) flying car design in this category. It’s lonely here for a reason: powered lift aircraft have unimaginably huge engine requirements, and therefore unrealistically expensive fuel consumption rates. Also, of all aircraft designed for slow flight, powered lift aircraft are by far and away the least stable and most dangerous (and difficult) to fly. Furthermore, any loss of power in “hover” configuration for any and all of these aircraft is immediately catastrophic, and very likely unrecoverable. ^[1]

^[1] “Unrecoverable” is an aviation engineering euphemism for, “You get real dead real quick.”

Gyroplane - Motorcycle

Probably the most promising design–that is, the simplest, safest, and cheapest–is to make a roadable gyroplane. Another way to look at it is to create a 3-wheel motorcycle with a rotor and a propeller. Of all the personal flying vehicles in the works, this one seems to be seeing the most progress. Here are a couple projects of note:

• Spark Design’s PALV
  This project is still in the design phase, but if the company’s claims are to be trusted, they’ve already created solutions to a number of thorny problems: a folding propeller and rotor solve the “where do I put these things” problem for when in “road” mode. They’ve also patented some system of allowing the three-wheeled vehicle to tilt into a turn like a two-wheel vehicle would. As far as I know, however, they haven’t produced a prototype, putting them quite solidly into last place in this race. The pictures sure look slick, though.
• Sean Cooper’s street-legal gyroplane
  Sean works in Silicon Valley, and commutes 50 miles to work every day. He managed to get his homebuilt gyroplane registered by both the FAA and, (after some persistence) the DMV. He has to take the rotor off to drive in traffic, and it currently only has one gear for road driving. But it’s a start.
• Larry Neil’s Sky Cycle
  Larry works for Carter Aviation Technologies, the creators of the CarterCopter. Larry’s also got his own company, which been working on a vehicle he calls the “Super Sky Cycle.” In a nutshell, it’s his Monarch gyroplane converted into a roadable vehicle. Thanks to Harley Davidson’s incessant lobbying, it’s trivially easy to register your own homebuilt motorcycle with the DMV; which, incidentally, is exactly what this “chopper” is classified as. This vehicle also has a folding rotor design for road use, and seems to be progressing quite quickly.

Airplane - Rotorcraft

This design attempts to take the best features of the Airplane world and tie them in to a rotorcraft (either Gyroplane or Helicopter). The most notable hybrid in history past was the Fairey Rotodyne: a remarkable 40-passenger craft with full hover capability but no tail rotor–instead it had tiny jet engines at the tips of each rotor blade. It had a top speed of about 190 mph; quite an achievement for its day.

In recent years, Carter and company has picked up the ball and created a hybrid gyroplane-airplane. Their purpose was to make such craft faster by slowing the rotor during cruise. Unfortunately, the CCTD craft crashed a few months back because of some lose bolts or something. While the pilots where fine, the craft was severely damaged. The company has decided, therefore, to focus their attention on the Monarch autogyro (the base design behind Larry Neil’s Sky Cycle) because of funding reasons.

If Carter’s experiment taught us anything, though, it’s that the advantages of both rotorcraft and fixed-wing crafts can be effectively combined without serious side effects. You can take any of the previously-mention rotorcraft and add small wings to get better high-speed performance.

You might expect, assuming that we only use present-day technology, that the flying car of the future will be a roadable aircraft that uses a rotor to take off at low speeds, and a small set of wings for lift at high speed. You might also expect the “AutomoRotorPlane” to have collapsible telescoping wings and a folding propeller and rotor that store out-of-the-way for road use.

A 2 to 4 passenger model would probably do about 80 mph on the freeway, and about 220 mph in the air, all on an engine that burns about 10 gallons of normal automobile fuel per hour. It wouldn’t look like a car, but you’d be the envy of all the neighbors as you back out of your driveway, pull onto the street as the main rotor slowly spins up, then gently lift off and turn toward downtown. You could smile to yourself as you zip 1000 feet above the Monday morning gridlock on your way to the office. A one-and-a-half-hour commute reduced to 8 minutes. Yeah, you can live with that.