Personal air vehicle
A personal air vehicle (PAV), also personal aerial vehicle, is an emergent aviation market that would provide on-demand aviation services. This term was first used by NASA in 2003 when it established the Personal Air Vehicle Sector Project, as part of the Aeronautics Vehicle Systems Program. This project was part of NASA Vehicle Integration, Strategy, and Technology Assessment (VISTA) office, which also included sectors for Subsonic Transports, VTOL Aircraft, Supersonic Aircraft, and High Altitude Long Endurance Aircraft. The objective of each sector was to establish vehicle capability goals and the required technology investment strategies to achieve those breakthroughs.
A ground transport alternative is enabled by unmanned aircraft technologies: Autonomous Systems and electric propulsion. Barriers include aviation safety, airworthiness, operating costs, usability, airspace integration, aircraft noise and emissions, tackled first by small UAS certification then experience.
Other names discussed include PIVITOLs (Personal Vertical TakeOff vehicles), Air-cars, PACs (Personal AirCraft), AVs (Air Vehicles).
The first technical paper to explain the difference in vehicle characteristics between PAVs and existing General Aviation single engine piston aircraft was "Personal Air Vehicles: A Rural/Regional and Intra-Urban On-Demand Transportation System" by Mark D. Moore (the NASA PAV Sector Manager) from NASA Langley Research Center. This paper was presented in September 2003 at an American Institute of Aeronautics and Astronautics (AIAA) conference as AIAA Paper 2003-2646. This paper established advanced concepts that would provide vehicle characteristics that dramatically enhanced the 1) Ease of Use, 2) Safety, 3) Efficiency, 4) Field Length Performance, and 5) Affordability. Many additional papers were presented at AIAA and Society of Automotive Engineers (SAE) conferences through 2006 that further refined the definition of PAV capabilities, technologies, and concepts. In 2006 the Vehicle Systems Program was replaced by new NASA Aeronautics initiatives. PAV technology development efforts at NASA shifted to a prize-based investment, with NASA Centennial Challenge Prize funds being provided for competitions in 2007 (Personal Air Vehicle Challenge, with $250,000 in prizes), 2008 (General Aviation Technology Challenge, $350,000 in prizes), and 2011 (Green Flight Challenge, $1,500,000 in prizes). All of these competitions were completed for NASA by the Comparative Aircraft Flight Efficiency (CAFE) Foundation in Santa Rosa, California.
A new mode of transportation
Currently the doorstep-to-doorstep average speed for cars is 35 mph. In the greater Los Angeles area, this speed is predicted to degrade to 22 mph by year 2020. The U.S. Department of Transportation (DOT) states that 6.7 billion US gallons (25,000,000 m3) of gasoline are wasted in traffic jams each year.
A future system of travel by PAVs avoids air traffic jams and can help to relieve those on highways.
PAV definition outline according to NASA
- Seats: Less than 5 passengers.
- 150–200 mph (240–320 km/h) cruising speed.
- Able to be flown by anyone with a driver’s license.
- As affordable as travel by car or airliner.
- Near all-weather capability enabled by synthetic vision systems.
- Highly fuel efficient (able to use alternative fuels).
- 800 miles (1,300 km) range.
- Provide "door-to-door" transportation solutions, through use of small community airports that are at closer proximities to businesses and residences than large airports.
Some private companies are using their own criteria for vehicles in this general category.
Barriers to PAV vision
The Federal Aviation Administration (FAA) infrastructure is not currently capable of handling the increase in aircraft traffic that would be generated by PAVs. The FAA plan to fix this is the Next Generation Air Transportation System for 2025. An interim plan is to use smaller airports. Modeling by NASA and others have shown that PAV's using smaller community airports would not interfere with commercial traffic at larger airports. Currently there are over 10,000 public and private small airports in the United States that could be used for this type of transportation. This infrastructure is currently underutilized, used primarily by recreational aircraft.
Noise from PAVs could also upset communities if they operate near homes and businesses. Without lower noise levels that enable residential landings, any PAV must take off and land at an FAA-controlled airfield, where higher sound levels have been approved.
Studies have explored ways to make helicopters and aircraft less noisy, but noise levels remain high. In 2005 a simple method of reducing noise was identified: Keep aircraft at a higher altitude during landing. This is called a Continuous Descent Approach.
The European Union is funding a 3-leg €4.2m study (under the Seventh Framework Programme) of technologies and impacts for PAVs; Human-aircraft interaction, Automation of aerial systems in cluttered environments, and Exploring the socio-technological environment.
Urban flight safety is a well-known problem for regulators and industry.[original research?]
On May 16, 1977, the New York Airways accident of a Sikorsky S-61 helicopter shuttle from JFK Airport which landed on the roof of the Pan Am Building (now MetLife) when a landing leg collapsed and a detached rotor blade killed several people on the helipad and one woman on Madison Avenue ended that business for decades almost around the world. Current helicopter accident rates would be insufficient for urban mobility. The Sikorsky S-92's safety-focused design still allows 1 fatal accident per million flight hours. This rate would lead to 150 accidents per year for 50,000 eVTOLs flying 3,000 hours a year.
For Sikorsky Innovations, the emerging $30 billion urban air mobility market needs safety at least as good as FAR Part 29 governing over 7,000 lb (3.2 t) helicopters. By May 2018, Sikorsky flew an S-76 120 hours with full point-to-point, real time autonomous flight and terrain avoidance the hard way, with Level A software and redundancy, with a safety pilot. Sikorsky Aircraft want to reach a vertical flight safety of one failure per 10 million hours on high-utilization platforms by combining current rotorcraft experience with advances in autonomous flight, airspace integration and electric propulsion.
Fulfillment of the NASA vision for PAVs is likely to unfold over several decades. Several vehicle types exist which strive to meet the PAV definition:
- Roadable aircraft
- Ultralight Helicopters
- Light Sport Aircraft
- Ultralight trikes (powered hang gliders with motorized wheels)
- Powered paragliders
- Motor gliders
- Vertical Take-Off and Landing Aircraft
Most vehicles in the above category do not meet all the requirements set by NASA. However, some vehicles come close. Ultrallight aircraft are of special interest since their energy usage is low. Hybrid forms of the vehicle types above can also be useful. Some hybrid forms that exist are:
- the Opener Aerospace Blackfly, an automated, electrically-powered personal VTOL with good energy efficiency.
- the AeroVironment SkyTote, a combination of airplane and a helicopter. It is also fully automated, similar to driverless cars.
- The Ornithopter, a similar helicopter/ornithopter hybrid.
- The Theolia Windream One and Hunt Aviation have come up with airship hybrids. Airships may also be foreseen with ground effect modifications.
- The Solar Impulse and the electric airplane feature all-electric propulsion.
Besides the fabrication of personal air vehicles, the creation of driverless systems for PAV's is also being researched. First off, synthetic vision electronic flight instrument systems (EFIS) as Highway in the sky (HITS) makes it much easier to control aircraft. Also, Phantom Works is working on designing a system that allows to automate PAV's. The PAV's are designated their own "lanes" in the sky, hereby ensuring the avoidance of possible collisions. In addition, the different PAV's are also capable of detecting each other and communicating with each other, further decreasing the risk of collisions.
NASA Langley has researched and prototyped the necessary PAV technologies and has dedicated the largest cash prize in the history of GA to the PAV that can demonstrate the best overall combination of performance. The PAV flight competition for this prize, known as the first annual PAV Challenge, was held Aug 4-12, 2007 and hosted the CAFE Foundation in Santa Rosa, CA.
In 2008 the challenge was renamed as the General Aviation Technology Challenge.
The new prizes were:
- The Community Noise Prize ($150,000)
- The Green Prize ($50,000) (MPG)
- The Aviation Safety Prize ($50,000) (Handling, eCFI)
- The CAFE 400 Prize ($25,000) (Speed)
- The Quietest LSA Prize ($10,000)
The winners were:
- Community Noise Lambada N109UA $20,000
- Green Prize no winner n/a
- CAFE Safety Pipistrel N2471P $50,000
- CAFE 400 Pipistrel N2471P $2,000
- Quietest LSA Lambada N109UA $10,000
- Shortest Takeoff Pipistrel N2471P $3,750
- Best Angle of Climb Pipistrel N2471P $3,750
- Best Glide Ratio at 100 MPH Flightdesign CTSW N135CT $3,750
- Cabin Noise (tie) Lambada N109UA Pipistrel N2471P $3,750 ($1,875 each)
Other notable designs
List of Personal Air Vehicles with VTOL capability
- Kitty Hawk Flyer
- Ehang Passenger_drone
- Hoversurf Scorpion 3 hoverbike
- CarterCopter / Carter PAV
- Terrafugia Transition
- Terrafugia TF-X
- Xplorair PX200
- Parajet Skycar
- Urban Aeronautics X-Hawk
- NASA Puffin
- Martin Jetpack
- Moller Skycar
- Volocopter 2X
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