Here are the DARPA guidelines:
OBJECTIVE: Define new and innovative technology components that enable building a vehicle which can either be used as a 2-4 person ground transport that can both drive on roads or be changed into a flying craft with vertical take off capability. Identify selected technologies providing propulsion, morphing wings, and/or flight controls that provide core elements for this multi-person vehicle. Identify issues to be resolved via trade studies and define demonstrations establishing the feasibility of the identified core component technologies.
DESCRIPTION: A personal air vehicle that could transport 2 to 4 personnel either by driving on the ground or by flying would be suitable for many military scouting and personnel transport missions. This personal air vehicle should also have a vertical take-off capability that is not restricted to prepared surfaces for the most military utility. Desired personal air vehicle characteristics would be the ability to fly for 2 hours carrying a 2 to 4-person payload on one tank of fuel and can also safely travel of roads. The vehicle must be no wider than 8.5 feet and no longer than 24 feet, and no higher than 7 feet when in the road configuration. Vehicle control must support manually driving the vehicle on the ground and fully automated flight with manual flight control inputs that can override the fully automatic system. The challenge is to define the major components of such a vehicle that would be suitable for military scouting and personnel transport missions, yet are small enough, inexpensive enough, and easy enough to operate that it can be widely used. To achieve this it will be necessary to explore new and innovative technologies in one or more of the following areas:
- Propulsion concepts that include vertical take off and vertical landing, optimized disk loading for the combined fly/drive mission, size, weight, and power suitable for a road drivable vehicle, efficient power plant and energy management combined with low specific fuel consumption, and installation considerations related to safety, vehicle controllability, and passenger/payload carrying on a vehicle. The optimized disk loading should allow safe take off/landing at unprepared sites.
- Morphing wing/surfaces considerations including safe and rapid deployment and retraction, rugged construction, and ease of operation for a vehicle that can drive at up to 60 mph and fly at up to 150 mph.
- Flight control considerations include human interfaces to autopilot, flight director, and/or auto-navigation systems, automated navigation/ positioning, automated sensors, automated fight planning and de-confliction with other users of the airspace. Size, weight, and power must be paramount as well as redundancy and reliability suitable for human passengers.