26-08-2014, 02:19 PM
flying cars
[attachment=67057]
1. INTRODUCTION
‘Flying car’, ‘roadable aircraft’, ‘dual-mode vehicle’ and other terms are used to describe the all-purpose vehicle that can fly like an airplane and drive on the highway like an automobile. Make it amphibious and we have the perfect all-purpose vehicle! Nevertheless, this might be taking our ideas a bit too far.
It has long been the dream of aviation and automobile enthusiasts to have a vehicle that will bring them the best of both worlds. Many drivers stuck in rush hour traffic have fantasies about being able to push a button and watch their car’s wings unfurl as they lift above the stalled cars in front of them. Just as many pilots who have been grounded at an airport far from home by inclement weather have wished for some way to wheel their airplane out onto the highway and drive home. This yearning has resulted in many designs for roadable aircraft since as early as 1906.
A designer of a flying car will encounter many obstacles, including conflicting regulations for aircraft and automobiles. As an automobile, such a vehicle must be able to fit within the width of a lane of traffic and pass under highway overpasses. It must be able to keep up with normal highway traffic and meet all safety regulations. It must also satisfy vehicle exhaust emission standards for automobiles. Therefore, the wings must be able to fold (or retract) and the tail or canard surfaces may have to be stowable. The emission standards and crashworthiness requirements will add weight to the design. The need for an engine/transmission system that can operate in the stop and go, accelerate and decelerate environment of the automobile will also add system complications and weight.
For flight, the roadable aircraft must be lightweight and easy to fly. It must have a speed range at least comparable to existing general aviation airplanes. Conversion from aircraft to car or vice versa must be doable by a single person and the engine must be able to operate using either aviation fuel or auto fuel. Ground propulsion must be through the wheels and not via propeller or jet which would present a danger to nearby people, animals or other vehicles.
2. DESIGN APPROACH
While some people use the terms Flying car and roadable aircraft interchangeably, or use the latter term to bypass the science fiction connotations of the former, they are explicitly two quite different concepts. One wishing to design such vehicles must first decide which approach is appropriate. The ‘flying car’ is primarily a car in which the driver has the option of taking to the air when desired or necessary. The ‘roadable aircraft’ is an airplane that also happens to be capable of operation on the highway.
In the past, most designs have actually been for roadable aircraft. They started out looking like conventional airplanes but with wings and possibly with tails that could be retracted or folded. Alternatively, they may be removed and towed in a trailer when the vehicle is operated on the road. Several such vehicles have been designed and built. A few, such as the Taylor Aerocar1 or the Fulton Airphibian, have been certified for use in flight and on the highway. Both types of vehicle have been sold to the public. The roadable aircraft is meant to be primarily an airplane but with the capability of being driven on roads to and from the airport. It must also be capable of getting the pilot and passengers to their desired destination on the highway when the weather prevents flight. As such, it is a vehicle primarily sold to licensed pilots. They would use its on-road capabilities in a limited manner, and not as a substitute for the family automobile for everyday trips to the supermarket. Typical problems with such designs have been their poor performance both in the air and on the road. Also, there has been in the past a reluctance of insurance companies to write policies which will cover their operation in both environments
.
The ‘flying car’, unlike the roadable aircraft, has proved to be more of a fantasy than an achievable reality. A key element in the development of a successful flying car is designing a control system that will enable a ‘driver’ who may not be a trained pilot to operate the vehicle in either mode of travel. This virtually necessitates a ‘category III capable’ automated control system for the vehicle. This must provide a ‘departure-to destination’ flight control, navigation and communication environment. Many experts feel that such a design is possible today, but only at high cost. Ideally, if the ‘flying car’ is to become the family car, it must have a price that is at least comparable to a luxury automobile (preferably less than 25 percent of the cost of the cheapest current four passenger general aviation aircraft).
Both the flying car and the roadable aircraft concepts usually assume a self-contained system capable of simple manual or even automated conversion between the car and airplane modes. A third choice is the dual-mode design which is capable of operation on the road or in the air but does not necessarily carry all the hardware needed for both modes with it at all times. One such vehicle was the Convair/Stinson CV-118 Aircar.Designed in the 1940s, it combined a very modern looking fiberglass body car with a wing/tail/engine structure that could be attached to the roof of the car for flight. This design successfully flew, and operated well on the highway, but was a victim of high cost and changing corporate goals for its manufacturer.
Another decision facing the designer of any airplane/automobile hybrid vehicle is whether to attempt to meet government standards for both types of vehicles. Unless one wishes to go to the extreme of developing a very lightweight flying motorbike which will operate under ultra-light regulations, one must meet FAR or JAR requirements for general aviation category aircraft. On the other hand, there is a choice when one considers the automotive aspects of the design.
Automobile safety and emission control requirements necessitate structural and engine designs that are heavier than one would ordinarily need for an aircraft. There is, at least under United States law, a ‘loophole’ in the regulations under which any roadable vehicle with fewer than four wheels can be classified as a motorcycle and not an automobile. This allows those who wish to avoid the extra weight and expense of meeting automobile design standards to develop a three-wheeled vehicle and classify the resulting design as a flying motorcycle, a vehicle that officially is an airplane in the air and a motorcycle on the road. Motorcycles have very few safety or emission design requirements beyond the specification of lighting, horn and engine muffler. Three-wheeled road vehicles do have operational speed restrictions in the United States.
Another decision that must be made is the extent to which the vehicle will meet the ‘luxury’ standards of automobile buyers that are not normally seen in general aviation aircraft. Atypical modern American automobile lists in its ‘standard’ equipment package air-conditioning, electric window controls and door locks, automatic transmission, CD/tape players and similar items. None of these are usually found in most general aviation aircraft and all add (sometimes considerable) weight to the aircraft.
5. CONCLUSION
The flying car concepts will require some more time to be in reality.
Roadable aircrafts design and development are feasible.
Cost of roadable aircrafts play a vital role in their success.
The success of roadable aircrafts will end uncertain weather, rising costs, and ground transportation hassles on each end of the flight.
[attachment=67057]
1. INTRODUCTION
‘Flying car’, ‘roadable aircraft’, ‘dual-mode vehicle’ and other terms are used to describe the all-purpose vehicle that can fly like an airplane and drive on the highway like an automobile. Make it amphibious and we have the perfect all-purpose vehicle! Nevertheless, this might be taking our ideas a bit too far.
It has long been the dream of aviation and automobile enthusiasts to have a vehicle that will bring them the best of both worlds. Many drivers stuck in rush hour traffic have fantasies about being able to push a button and watch their car’s wings unfurl as they lift above the stalled cars in front of them. Just as many pilots who have been grounded at an airport far from home by inclement weather have wished for some way to wheel their airplane out onto the highway and drive home. This yearning has resulted in many designs for roadable aircraft since as early as 1906.
A designer of a flying car will encounter many obstacles, including conflicting regulations for aircraft and automobiles. As an automobile, such a vehicle must be able to fit within the width of a lane of traffic and pass under highway overpasses. It must be able to keep up with normal highway traffic and meet all safety regulations. It must also satisfy vehicle exhaust emission standards for automobiles. Therefore, the wings must be able to fold (or retract) and the tail or canard surfaces may have to be stowable. The emission standards and crashworthiness requirements will add weight to the design. The need for an engine/transmission system that can operate in the stop and go, accelerate and decelerate environment of the automobile will also add system complications and weight.
For flight, the roadable aircraft must be lightweight and easy to fly. It must have a speed range at least comparable to existing general aviation airplanes. Conversion from aircraft to car or vice versa must be doable by a single person and the engine must be able to operate using either aviation fuel or auto fuel. Ground propulsion must be through the wheels and not via propeller or jet which would present a danger to nearby people, animals or other vehicles.
2. DESIGN APPROACH
While some people use the terms Flying car and roadable aircraft interchangeably, or use the latter term to bypass the science fiction connotations of the former, they are explicitly two quite different concepts. One wishing to design such vehicles must first decide which approach is appropriate. The ‘flying car’ is primarily a car in which the driver has the option of taking to the air when desired or necessary. The ‘roadable aircraft’ is an airplane that also happens to be capable of operation on the highway.
In the past, most designs have actually been for roadable aircraft. They started out looking like conventional airplanes but with wings and possibly with tails that could be retracted or folded. Alternatively, they may be removed and towed in a trailer when the vehicle is operated on the road. Several such vehicles have been designed and built. A few, such as the Taylor Aerocar1 or the Fulton Airphibian, have been certified for use in flight and on the highway. Both types of vehicle have been sold to the public. The roadable aircraft is meant to be primarily an airplane but with the capability of being driven on roads to and from the airport. It must also be capable of getting the pilot and passengers to their desired destination on the highway when the weather prevents flight. As such, it is a vehicle primarily sold to licensed pilots. They would use its on-road capabilities in a limited manner, and not as a substitute for the family automobile for everyday trips to the supermarket. Typical problems with such designs have been their poor performance both in the air and on the road. Also, there has been in the past a reluctance of insurance companies to write policies which will cover their operation in both environments
.
The ‘flying car’, unlike the roadable aircraft, has proved to be more of a fantasy than an achievable reality. A key element in the development of a successful flying car is designing a control system that will enable a ‘driver’ who may not be a trained pilot to operate the vehicle in either mode of travel. This virtually necessitates a ‘category III capable’ automated control system for the vehicle. This must provide a ‘departure-to destination’ flight control, navigation and communication environment. Many experts feel that such a design is possible today, but only at high cost. Ideally, if the ‘flying car’ is to become the family car, it must have a price that is at least comparable to a luxury automobile (preferably less than 25 percent of the cost of the cheapest current four passenger general aviation aircraft).
Both the flying car and the roadable aircraft concepts usually assume a self-contained system capable of simple manual or even automated conversion between the car and airplane modes. A third choice is the dual-mode design which is capable of operation on the road or in the air but does not necessarily carry all the hardware needed for both modes with it at all times. One such vehicle was the Convair/Stinson CV-118 Aircar.Designed in the 1940s, it combined a very modern looking fiberglass body car with a wing/tail/engine structure that could be attached to the roof of the car for flight. This design successfully flew, and operated well on the highway, but was a victim of high cost and changing corporate goals for its manufacturer.
Another decision facing the designer of any airplane/automobile hybrid vehicle is whether to attempt to meet government standards for both types of vehicles. Unless one wishes to go to the extreme of developing a very lightweight flying motorbike which will operate under ultra-light regulations, one must meet FAR or JAR requirements for general aviation category aircraft. On the other hand, there is a choice when one considers the automotive aspects of the design.
Automobile safety and emission control requirements necessitate structural and engine designs that are heavier than one would ordinarily need for an aircraft. There is, at least under United States law, a ‘loophole’ in the regulations under which any roadable vehicle with fewer than four wheels can be classified as a motorcycle and not an automobile. This allows those who wish to avoid the extra weight and expense of meeting automobile design standards to develop a three-wheeled vehicle and classify the resulting design as a flying motorcycle, a vehicle that officially is an airplane in the air and a motorcycle on the road. Motorcycles have very few safety or emission design requirements beyond the specification of lighting, horn and engine muffler. Three-wheeled road vehicles do have operational speed restrictions in the United States.
Another decision that must be made is the extent to which the vehicle will meet the ‘luxury’ standards of automobile buyers that are not normally seen in general aviation aircraft. Atypical modern American automobile lists in its ‘standard’ equipment package air-conditioning, electric window controls and door locks, automatic transmission, CD/tape players and similar items. None of these are usually found in most general aviation aircraft and all add (sometimes considerable) weight to the aircraft.
5. CONCLUSION
The flying car concepts will require some more time to be in reality.
Roadable aircrafts design and development are feasible.
Cost of roadable aircrafts play a vital role in their success.
The success of roadable aircrafts will end uncertain weather, rising costs, and ground transportation hassles on each end of the flight.