Moller International was requested to determine if it could integrate its vertical take-off and landing (VTOL) technologies into a vehicle that would be more car-like than its Skycar® or Neuera™ vehicles. The purpose of this new vehicle would be primarily on the ground and on conventional roadways, but its novelty would be to have the ability to “pop-up” out of traffic and fly to a near-by, less crowded area. This scenario was given and the legalities were dismissed, therefore we were free to design a vehicle with the appeal of a modern roadster and the combined road-and-airborne capabilities of a volantor.
Today's typical vehicle design flow incorporates a series of distinct stages. The initial phase includes the functional specification and system design, followed by the specification and design of all components. Moving into the prototype stage, components are tested and verified against specification. However, it is not until the full system integration and verification phase, when physical components are connected for the first time, that any problems arising from the functional specification and system design stages become apparent.
For the initial design phase of the autovolantor we chose to use the Ferrari 599 GTB (shown modified below) for the basic fuselage. It had the general shape and layout we were looking for and using it allowed us to quickly modify a readily available scale model and run wind tunnel tests to establish the technical feasibility of the project. At first we were very skeptical that we could adapt a ground-vehicle with our VTOL technologies and make it work, but the model allowed us to quickly verify that it could in fact be done. For a final design we would, however, start fresh and design an entirely unique body, but for the first cut, the Ferrari 599 GTB had the front and rear decks that could accommodate our engine mounting requirements.
The timeline for development of the vehicle was analyzed and we estimated that we could produce a prototype-flying vehicle in approximately 6 months given sufficient funding. The budget was determined to be approximately $5 million. The party that was initially interested ran into financial problems, so we are on-hold with this project at this time.
When operating on the ground the autovolantor is powered by batteries alone for the first 35 miles. Beyond 35 miles one of the engines is used to provide power for electrically driven wheels. No gearboxes are required as the fans are connected to the motor/engine shafts directly. Speed and stability in the air are controlled by a set of redundant computer systems. Small vanes in the exit area of the ducts can direct the air back or down for vertical take-off and landing. The autovolantor maneuvers at low speed like a helicopter, tilting its nose down to move forward, rolling right or left to maneuver sideways. At higher speeds it operates like an airplane. Since the vehicle is not aerodynamically stable until it reaches higher speeds, the control system constantly monitors the attitude of the vehicle and maintains stability through duct thrust control.
In a proposed hybrid version 60% of the installed power is from state-of-the-art batteries while the other 40% is from rotary engines. For take-off and hovering 670 hp is required, so auxiliary electric motors kick in and provide the additional hp for up to 90 seconds. The minimum time required for take-off and transition is 22 seconds. Allowing for a 20% reserve for engine failure, acceleration, and control, ~800 hp in total power is installed, 320 hp from engines and 480 hp from electric motors.
All of our power and range assumptions are based on using gasoline for fuel, although the Rotapower engine runs equally well on other "light" fuels such as ethanol, CNG, etc. "Heavy" fuels such as diesel or JP-8 require a different fuel delivery system.
Ground speeds are projected to be up to 80 mph, and maximum air speed would be 165 mph. The maximum all-airborne range is 104 miles at 9.6 mpg and maximum all-ground range is 545 miles at 45.4 mpg. Our analysis indicates that miles per gallon vary for the 12 gallon fuel capacity. A typical 50-mile flight plus 300 mile ground trip would result in 29.3 mpg, while a 10-mile flight plus 486 mile ground trip would provide 41.3 mpg. Range on batteries alone is 35.5 miles (assuming an 85% discharge). If the industry is able to double the battery energy storage capacity over the next two years (a goal of the GM Volt and other Hybrid automobile programs) it could extend the autovolantor's battery powered ground range to 70 miles.
While maximum altitude for this vehicle could be much higher, the practical height limits for a short-flight-duration aircraft like the autovolantor are relatively low, and would probably be just above city buildings and well below other air traffic.