A Guide to Flying Cars

Flying cars is a hype theme. Brad Templeton, a pioneer in the field of robotic cars, is trying, coldly, to sort out and classify those options that really exist.

Now there are many options for candidates for flying cars, a kind of Cambrian explosion. Consider some of the main design options, their advantages, and try to figure out who is more likely to win the evolutionary race.

Fixed-wing rotors or rotors

Multi-rotor eHang for 2 people, introduced in 2017. Already flies

Currently, the multi-rotor drone does not cause any more questions and problems. We know how to build it. It is not very effective, so its flight range is limited by batteries. Since he was already dealt with, drones were the first devices capable of taking off. They are pure multicopters such as the Volocopter (with 18 rotors) and eHang. There is another subcategory: “Hoverbikes” (“flying motorcycles”), which are even more like a consumer drone, as they only have one seat, which is often located above the propellers. This includes the first Kitty Hawk, the Flyer.

It is much easier to do, so there is more mention of it in the press. It can be considered as an increase in the multicopter, so that something happens that can withstand 60-120 kg of load and fly for 30 minutes. However, there is a limit, as the battery becomes larger (to withstand more load and cover a greater distance), it becomes heavier, thereby reducing the allowable load and flight range while increasing cost.

The biggest problem is that a quadcopter is even worse than a helicopter in terms of efficiency. A design with a decent flight range, as a rule, has a hybrid electric drive.



Volocopter is a drone-like vehicle that is already flying. The radius of flight is smaller, but the design is simpler.

That is why most of the teams work on some hybrids that take off like multicopters, but they have a wing and immediately after takeoff they (multicopters) turn into a regular airplane. The wing is not needed for normal take-off, it should not be as large as on conventional aircraft.

Rotorcraft (and other deviated thrusts)

Test flight of the Airbus Vahana with fixed propeller position and deflectable wing.

The oldest design for aircraft with two rotors and a wing is a swivel rotor. Large rotors face up and can be tilted forward. The V22-Osprey is notorious for its similar design, which has led to fatal accidents.

However, the knowledge gained during the construction of this design at Bell Helicopter led to the Nexus design, which used deflected, closed propellers. Other designs install rotors on the wing and tilt the entire wing assembly. Lilium Jet places them in the tail and also tilts.



Lilium Jet - many rejected propellers. Declared a very high speed and range.

The trick is that you must safely deflect the rotors during takeoff and landing. It is not simple.

Pusher propeller (Pusher prop)

If you do not deflect the rotors, you can fly by adding an additional, more traditional propeller, usually from behind. This is the construction of Kitty Hawk Cora, and several other aircraft, including the Elroy cargo plane. The latter uses a gasoline engine to directly control the thrust propeller.



Kitty Hawk Cora test flight with 12 rotors for VTOL and fixed wing propeller.

The design is simple - without a slope, which will be a big problem if something goes wrong. This means that all rotors remain stationary for most of the flight, providing resistance instead of traction or lift.

Deviated fuselage (tilt-plane)

Opener "Blackfly" is already flying. The design is very simple, 8 rotors.

Opener offers an interesting alternative. It has two wings with 8 rotors mounted on them, and the wing is installed at an angle to the fuselage. It takes off with rotors pointing vertically, and the pilot deviates strongly backward, and the entire plane deviates with it until the wings and rotors take a horizontal position, and the pilot is in front and slightly lower. For the pilot, this is not very comfortable, but it contributes to the absence of moving parts, with the exception of rotors and control surfaces.

All-electric or hybrid

Central to the VTOL revolution is the use of an electric motor. This allows you to create a completely new type of VTOL, different from old-school helicopters. Today's batteries are hardly good enough, so the range and size of the vehicle are limited. One alternative is to install a generator in addition to batteries, usually powered by gasoline or jet fuel. Batteries will still be needed for VTOL peak power, and to land safely if the generator fails. Since generator failure is now a lesser threat, you can install a motor that is not as reliable and expensive as conventional aircraft engines.

Gasoline is popular because it can be bought anywhere. But at the same time, it is not so easy to supply gas stations everywhere, including on the roofs of buildings and on private landing sites. It’s easier to get permission for electric charging stations.

In addition, this approach is not particularly environmentally friendly. People do not want to develop a new transport that will pollute even more of the old.

An alternative, not yet common, is the use of fuel cells. Hydrogen is a very dense fuel, if we talk about its weight, plus it requires bulky tanks. It is not easy to find or refuel it. Today, fuel cells are quite expensive, so you still need batteries for VTOL and emergency landings.

Large, small or without wheels

Some teams take the term “flying car” literally - they want a vehicle that can move on wheels on the ground, make it small enough to drive on roads and park in parking lots and even in private garages. Others want the vehicle to be able to simply make small movements around the airfield, for example, go to a parking lot or to charging stations. Still others do not plan any wheels - the car remains in the same place where it lands.

A compromise is not so simple. One big question is where to put all the vehicles if you can’t drive them. Many designs, although not huge, are still the size of 4 or 6 cars. If there are a million of them, then there will be no place in the city where they could be put. Even if there are 100 thousand, it’s still a lot. They can move in open areas, fly to charging ports, but cannot be anywhere where they cannot land. They can take off and move to other sites when you need to wait until they clear the airfield, but they will not be able to ride on the roads.

On the other hand, wheels and the ability to drive add moving parts, complexity and, worst of all, weight. Weight is very important. Each kilogram is worth a kilogram of payload or battery. We are balancing on the verge of a decent flight range and load, and wheels, motors and everything you need to legally drive on roads only complicate the task.

So perhaps the ability to fly is better left to flying vehicles, and the car should remain a car. A flying machine can land, and a person can get out of it and get into robotsi. This is not so bad. A car is a car, and an airplane is an airplane.

Airbus offers a rather strange hybrid approach. It consists in installing a “passenger container”, which can either be picked up by the flying part, or can be placed in a traveling cradle with wheels. Thus, the container with the passenger will fly with the chassis above them, after which the container is landing, placing it in a moving base. The rotors detach and fly away to attach to another car, while the container is pinched at the base of the cradle and can travel on the road. This solves the problem of weight, but it is very difficult, and you can land only where there are such containers.
Another problem is that road vehicles must be certified for road safety, and for this they must have a lot of weight.

Some designs, such as Opener Blackfly, can also land on water and grass. They have no wheels and they cannot move on land at all.



Terrafugia is a transitional option between a traditional fixed-wing aircraft with gasoline, it can only fold a wing for riding on the road.

One of the oldest designs, the Terrafugia Transition, flies strictly like a fixed-wing aircraft; its wing folds so that it can ride on roads on wheels. This is an old-school (practical) idea of ​​a flying car, but because of VTOL even Terrafugia switched to a different design.

Currently, only very few designs have wheels or their layout.

Runway or lack thereof

Some vehicles still use the runway. Airplanes are no longer a problem, and they can be effective. The original Terrafugia mentioned above is a classic example. Multicopter takeoff is loud, and it consumes a lot of energy. Runways use a lot of land, and there are few of them. One option is to combine Robotaxi with a fixed wing aircraft. Robotaxi takes you directly to the plane, you quickly switch everything and take off. Same thing in reverse order. This will allow you to create flying cars with high efficiency and range, and it’s worth fighting for.



Pal-V gyroplane / car in “folded mode” in the garage.

Some others are interested in gyroplane designs. Autogyro is also a very old technology, and it is now available. Autogyros need a very short runway to take off or land. So short that many parking lots or even the roofs of buildings will do. However, they are not as effective as airplanes. Previously, they successfully managed to sell them due to the fact that they are more effective than helicopters, but now this is not so relevant.

However, a personal flying vehicle is in greater demand than many cars today.

Open blades, protected blades, screw in the annular cowl

In some designs, the open rotor blades, and sometimes they are trying to integrate them into the body, into shields or into the annular cowl. By protecting them, you can reduce noise and risk for pedestrians, but this can increase weight and interfere with airflow. The screws in the annular cowl can produce strong traction if done correctly, but this is difficult.



Bell Helicopter with six gigantic oblique propellers in annular cowls.

It is unclear whether the security authorities will put up with open blades that can harm people, especially if vehicles land on roadways and car parks as many want.

Licensed pilot, drone operator or battery life

Ultimately, everyone hopes to make fully autonomous taxis. Under current law, this is not possible, and this is still a problem. Some machines will initially be released for use only with a licensed pilot. Due to the weight of the battery, they are difficult to qualify as “light sports aircraft” that require a simpler pilot license, they cannot be called ultralight, but there are suggestions that the FAA (Federal Aviation Administration) may change the allowable weight to deal with electric cars on batteries that have never been expected before. If they do, this will allow vehicles to move off the ground and fall into the hands of users before the automation is ready for use or legal.

There are some suggestions that those that look most like drones can fly with a basic pilot license designed for remotely controlled drones, but I'm not sure if this will be applied after testing.

Large capacity taxis or private car

A few years ago they announced Uber Elevate , a major initiative to get companies to develop air taxi services that Uber can manage to move people between helicopter ports. Uber Elevate said that it will be vehicles with 4 passengers and a pilot (there is no automation yet) and mainly taking off from the roofs of buildings in densely populated cities so as not to load traffic even more. This is one vision that has led to the emergence of many vehicle designs. Trying to make these cars only on the same batteries is another challenge. At the same time, many others focused on a personal car, with 1-3 passengers and autopilot mode. They are intended either for private ownership or for taxis over short distances.

Flight, model, prototype or dream

Hoversurf is an example of an excellent hoverbike, minimalistic, for one person.

While there are almost 100 projects, and even more are closed, they are all at different stages of development. Only 3 accept orders or sell. Only a few have full-size flying vehicles capable of traveling any distance. A few more have full-scale prototypes, but they made only vertical flight. On the other hand, some of the companies such as Airbus, Boeing, Bell Helicopter and Embraer have extensive resources and aviation experience. A few more companies have full-size flying models. The rest of the 81 companies listed on TransportUp have only designs and computer models. The first cars ready for production are older designs (like the Pal-V and Terrafugia), cars with only a rotor (like the Volokopter and some flying motorcycles) and quite possibly Blackfly, claim that it will be put up for sale this year in the range of $ 70 thousand

Who will win

At the moment, there is a lot of debate on this topic. However, I believe that the following designs will most likely win:

1. A quadcopter and a fixed wing, providing efficiency and range.
2. Small and able to some extent to move around places where they will wait for passengers, but not able to travel long distances on roads.
3. With protected blades to land in a variety of places and be quieter.
4. Designed for one or two passengers to stay small and light.
5. Tilting aircraft or propeller-driven aircraft to avoid the movement of complex parts of the rotor.
6. Initially in need of a pilot, ideally in a limited pilot license.

In the meantime, let a thousand designs bloom.

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