Personal mobility increases since the first man had the idea to take the first ride on a horse. Horses were complemented by carriages, engines were added to carriages, and then in 19th century the car was build. Also in the late 19th century the next important milestone in increasing mobility was done: The first manned flights! The air transport system was born. And, like the ground-based transportation system, it is still developing – you can say it’s already a young child… Today we can’t imagine how people in 100 or 1000 years will move from A to B. When the first plane flew there were already creative people, who wanted to let their cars fly. That’s a nice idea - but also a big problem in the early 20th century. There is no lightweight material, cars are made from steel, building a combination of planes and cars seemed to be an insuperable barrier. But, both transport systems were growing. New technologies and materials reached the market, and so, in the 1950s, a flying car made his maiden flight (see FIG. 1). In the last 40 years many flying cars were designed mainly by individual persons, and played a role in famous movies. They represent a man’s dream, however their market penetration was more than marginal due to certification hurdles and their non optimal implementation capability into both, the ground and the air transportation system.
FIG. 1: Hallock's "Road Wing" Concept from the 1950s1
But do we really need this exceptional vehicle? Is there a market for this product? Are there, today or in future, missions that require flying cars? The main factor that has to be determined is the time benefit that is reached by replacing today’s transportation chain, using cars and planes, by flying cars. The major task after determination the demand of flying cars is implementing them into the Air Transport system. Furthermore the wing configuration is an important aspect. A plane with the unconventional requirement “drive on streets” has to respect the circumstances of modern road traffic and the road traffic licensing regulations. The next challenge is the estimation of an innovative, low-emission propulsion system that uses energy-recovering methods in street traffic situations and respects the long range requirement for flights.
FIG. 2: Terrafugia Transition Car Concept2
Benefits to the Air Transport System
General aviation aircraft manufacturers often have problems implementing new technologies into their aircraft. Especially the piston engines used in many modern aircrafts were designed decades ago. Developing flying cars could bring new partners together: Automotive engine manufacturer, developing their low-emission technologies for millions of engines used in cars, and airframers. The benefit of this partnership may be know-how- and technology-transfer that makes to smaller aircraft manufacturers. This could increase the competitive pressure to the big aircraft-engine supplier Continental and Bombardier to renew their propulsion concepts. Another transfer is also possible: A lightweight car, made from carbon composites, which is even able to fly, could be used by the carbon fiber industry, to bring their material into another market. This influence helps increasing demand and reducing production costs for lightweight materials. A flying car – or roadable plane – needs no hangars at the airport. The pilot drives directly from the airfield into the garage. Local placed planes allow small airfields with less peripheral devices – like hangars, extensive taxiways and parking-lots for the pilot’s cars.
Likelihood of public acceptance
As mentioned above, flying cars represent a dream for increasing personal mobility. Common traffic jams are a big problem, people want to escape from this situation. Flying cars give the assurance of unlimited freedom, that’s what makes them famous. However, safety aspects play an important role. Of course no one would accept vehicles, starting wherever their drivers want to. Take off and landing strictly has to be limited to certified airfields. Users of flying cars need both – a driver license and a private pilot license. They are responsible for the transportation of their “payload”. That assigns several unknown duties to the users: A significant preparation, as known from private pilots, is necessary for every trip.
Low emissions become more and more important for the public acceptance of transportation systems. That is valid for planes and cars equally. Due to the vehicle’s lightweight structure, the energy required in common street traffic situations is low compared to conventional cars. Furthermore the aerodynamic efficiency, required for flight, lowers emissions during high-speed runs on streets.
The combination of car and plane offers totally new transportation scenarios. It allows the passengers to get into the vehicle at home, and leave it when they arrive at their destination. Furthermore it offers mobility in the destination area. Rental cars become redundant. Especially short trips gain attractiveness – wasted time on airports between check-in and boarding are a thing of the past. No more baggage-carrying through the vastness of never ending terminals. This could help to radically decrease capacity issues at airports.
Credibility of the physics
All technologies, required to build and use flying cars, are state of the art. In March 2009, the Transition, a roadable plane, successfully completed its maiden flight in the US. It is absolutely no problem to design and build combinations of cars and planes. It just has to be done.
Criteria for successful Incubation
A new product that shares a fractional amount of the market it belongs to is not able to change any boundary conditions. This applies to flying cars too. They can be successful – but they have to respect today’s and future’s street- and air-traffic scenarios.
Furthermore, they have to consider two kinds of certification specifications: The road traffic licensing regulations, in Germany StVZO (Straßenverkehrs-Zulassungsordnung) and the Certification Specifications for Very Light Aircrafts (CS VLA) which imply a MTOW of 750kg.
As mentioned above, also CO2 emissions have to be limited to guarantee both, public acceptance and respecting certification specifications.
During incubation the following aspects should be investigated:
- What is the time benefit that is reached by replacing today’s transportation chain, using cars and planes, by flying cars on certain to be defined missions.
- How can flying cars safely be implemented into the current ground and air transport system
- How can the wing mechanism be designed?
- Selection of an innovative, low-emission propulsion system that uses energy-recovering methods in street traffic situations and respects the long range requirement for flights.
Timescale for Incubation
A period of two years will be necessary to answer the key questions.
Budget required for Incubation
450000 € might be needed (three university researcher for two years) to determine imaginable missions, define the markets and detect the detailed requirements. Also concepts for the wing mechanism would be investigated.
Partnering needs for Incubation
As a result of the multidisciplinary requirements, different partners are necessary. Next to the core team including an overal air transport system expert, a propulsion expert and an expert in structural design, a general aviation aircraft manufacturer could serve as supporter because of its know-how in designing small aircraft. Furthermore, the street traffic scenario has to be considered. A co-operation with the institute of traffic engineering (TU München) would be helpful.
Related and supporting capabilities
The system “flying car” has the capability to save time, energy and costs. It also promises freedom and fun. Otherwise the customer has to treat it like a plane. That’s expensive – special maintenance partners are necessary. The preparation for flight is time-consuming.
A major related capability will be Air traffic Control if the Flying Car is to be more than the plaything of the few. For it to be adopted in any numbers - for example its use as a regular commuter vehicle - the control numbers would need to be considered very carefully. This also opens up the issue of prefered routes and prohibited areas. These may be the same as for other VLA but there may be a need for additional restrictions or additional waivers in large urban areas to allow for considerable numbers of Flying Cars.
Scalability of the idea
- Flying car is scalable from 1 to 10 passengers….
- Possible to create UAVs for military forces
- User flying cars in military scenarios
It is conceivable that flying cars are build to carry 1 up to 5 or even more passengers. The military could demand these vehicles to realize special missions. After all, primary the payload is scaled. Secondary, of course, the number of pieces rises, provided that there is a market. Scaling the payload causes modulation of the whole plane configuration. Rising number of pieces bring other problems: The count of flying cars that can be integrated into the air transport system without general changes is limited.