Personal air vehicle
A personal air vehicle or 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 is planning the Next Generation Air Transportation System targeted for 2025 to expand and completely transform the current aged system. Modeling by NASA and others have shown that PAV's using smaller community airports would not interfere with traffic at larger airports serving the commercial fleet. Currently there are over 10,000 public and private small airports in the United States that could be used for this type of transportation, which is currently being underutilized primarily by recreational aircraft.
Community noise generated by aircraft is a factor for PAVs that would be operating in close proximity to homes and businesses with much greater regularity that existing recreational aircraft. Without lower noise levels enabling residential landing capabilities, any PAV must still take off and land at an FAA controlled airport or private airfield, where the higher sound levels of operating aircraft have been approved.
Studies have been performed to determine 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, called Continuous Descent Approach.
The European Union is funding a 3-leg €4.2m programme (under the Seventh Framework Programme) to study technologies and impacts for PAVs in a Personal Air Transport System; Human-aircraft interaction, Automation of aerial systems in cluttered environments, and Exploring the socio-technological environment.
Current helicopter accident rates like the Sikorsky S-92 safety-focused design of 1 fatal accident per million flight hours would be insufficient for urban mobility leading to 150 accidents per year for 50,000 eVTOLs flying 3,000 hours a year. On May 16, 1977, the New York Airways accident of a Sikorsky S-61 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 rotorcraft experience combined with advances in autonomous flight, airspace integration and electric propulsion will benefit vertical flight safety to help Sikorsky Aircraft want to reach one failure per 10 million hours on high-utilization platforms.
For Sikorsky Innovations, a safety at least equivalent to the FAR Part 29 governing over 7,000 lb (3.2 t) helicopters is necessary for the emerging $30 billion urban air mobility market. As of 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.
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 can not yet perform all of the requirements set by NASA. However, some vehicles falling under the above have already set-down fair all-round performance in all of NASA's requirements. Especially ultralight aircraft are of specific interest since their energy consumption is very low. Hybrid forms of the vehicle types above can also be useful. Some hybrid forms that exist are:
- the AeroVironment SkyTote is a combination of airplane and a helicopter. It is also fully automated, similar to driverless cars.
- The Ornithopter is 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
- Graham Warwick (May 6, 2016). "Problems Aerospace Still Has To Solve". Aviation Week & Space Technology.
- FAA NGATS Archived 2006-10-17 at the Wayback Machine.
- "Reducing Airplane Noise: Acoustical Engineers Find Simple Way to Reduce Airplane Noise". ScienceDaily. July 1, 2005.
- Czyzewski, Andrew. Personal flying vehicles project aims to end road congestion The Engineer (magazine), 22 June 2011. Accessed: 26 July 2011.
- myCopter European Union, 2011. Accessed: 26 July 2011.
- Guy Norris (Jan 26, 2018). "Reality Check for Urban eVTOL On Safety And Production". Aviation Week & Space Technology.
- Mark Huber (May 1, 2018). "Sikorsky Exec Stresses Urban Air Safety". AIN online.
- Bellows, Alan (2006-03-31). "Gravity powered plane". Damninteresting.com. Retrieved 2011-04-25.
- Harry Kraemer (2003-12-01). "Highway in the sky". Aviationtoday.com. Retrieved 2011-04-25.
- Gary Sanders (July 2004). "Boeing technical experts check the feasibility of Personal Air Vehicles". Boeing Frontiers.
- "NASA Announces Aeronautical Centennial Challenge". NASA. July 28, 2005.
- "2007 NASA PAV Challenge Results". CAFE Foundation. August 16, 2007.
- Danny Hakim (June 16, 2014). "A Helicopter of One's Own". The New York Times.
- Mark Huber (Dec 2017). "It's a bird, it's a plane, it's…an Uber?". Business Jet Traveler.
- "The Electric VTOL News". The Vertical Flight Technical Society.
- "Are air taxis on a ride to nowhere?". Flight International. 19 Feb 2018.
- Stephen Trimble (21 Feb 2018). "Electric unmanned rotorcraft make economic case for air taxi role". Flightglobal.
- R. John Hansman, Parker D. Vascik (April 21, 2016). "Operational Aspects of Aircraft-Based On-Demand Mobility" (PDF). Joint University Program for Air Transportation.
- Fast-Forwarding to a Future of On-Demand Urban Air Transportation (PDF). Elevate (Report). Uber. October 27, 2016.
- Michael J. Duffy; et al. (May 2017). "A Study in Reducing the Cost of Vertical Flight with Electric Propulsion" (PDF). The Boeing Company.
- Arthur Brown and Wesley L. Harris (January 2018). "A Vehicle Design and Optimization Model for On-Demand Aviation" (PDF). Massachusetts Institute of Technology.