EVLN: Personal Electric VTOL Airplane That Won't Need A Runway

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EVLN: Personal Electric VTOL Airplane That Won't Need A Runway

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NASA Samarai hybrid-electric VTOL personal-aircraft concept

Invention Awards 2014: A Personal Electric Airplane That Won't Need A Runway
By Elbert Chu  04.01.2014

S2 Illustration by Benjamin Louis

This vertical-landing plane runs on electricity

More than half of all personal aircraft accidents occur during takeoffs or landings. That’s why inventor and entrepreneur JoeBen Bevirt—known for designing airplane-like wind energy turbines—is intent on making runways obsolete. Bevirt, 40, has mobilized his wind energy team to create a personal electric airplane called S2 that takes off vertically, like a helicopter, and flies aerodynamically, like an airplane.

No full-scale prototype exists yet, but Bevirt and his team have built about two dozen 10-pound models to demonstrate their concept works. NASA has taken notice and is now funding the development of a 55-pound unmanned aerial vehicle. Supercomputer simulations of a full-scale, 1,700-pound S2 suggest it could fly two people about 200 miles (New York City to Boston) in an hour on 50 kilowatt-hours of electricity, or roughly equivalent to 1.5 gallons of fuel used by a typical two-seat airplane—which would make the new aircraft about five times more efficient.

S2 wouldn’t have been possible just a decade ago, says Bevirt, who believes new compact and efficient motors, ever-increasing power density in batteries, smarter control systems, and tinier sensors mean his plane will soon be a reality. “There has never been a better time to be an aircraft designer,” he says.


A dozen compact electric motors operate three times more efficiently than a typical personal airplane’s combustion engines. Bonus: More motors improve redundancy and lower the risk of accidents.


Retractable arms reposition the motors to transition between vertical takeoff, forward flight, and landing.


Computers adjust motor speed 4,000 times per second to optimize efficiency, reduce noise, and improve flight control.

Lead Inventor: JoeBen Bevirt
Development Cost To Date: "Several million dollars"
Company: Joby Aviation
[© 2014 Popular Science]

Unleashed - the Samarai Way
by Graham Warwick  Jul 17, 2011


All concepts: NASA


NASA Samarai hybrid-electric VTOL personal-aircraft concept
theworacle· Jul 18, 2011
NASA concept for a vertical take-off and landing personal aircraft that combines a lightweight electric lift system with an internal-combustion cruise engine. This provides longer range than possible on battery power alone. The single-blade prop-rotors are stopped in flight to act as wings. This reduces drag. The concept takes its name from the single-blade rotor's similarity to the samara, or maple seed.

Electric aircraft are here today, but available battery technology severely limits their size and performance. Hybrid-electric propulsion is a solution, using fuel to provide sufficient energy storage and an internal-combustion (IC) engine to generate the electricity.

NASA is looking at a vertical take-off and landing personal-aircraft concept that combines an IC cruise engine with a lightweight electric lift system. The Samarai* reduces drag in forward flight by stopping the single-blade wingtip rotors so they can act as extensions to the wings.

NASA aerospace engineer Mark Moore says a key objective with Samarai is to achieve propulsion redundancy all the way out to the tips of the prop-rotors. One way this is achieved is by using short-range laser scanners at each corner of the vehicle to watch for potential blade strikes and quickly stop the affected prop-rotor before impact.

He says a test rig was built that showed electric motors can be stopped in any position "incredibly quickly", especially given each single-blade rotor's small size and low weight. The result is a compact configuration, although there is some wasted rotor thrust from download on the wings, Moore says.

Samarai is a more practical follow-on the NASA's Puffin concept for a lightweight single-person VTOL aircraft. The all-electric Puffin weighs less than 300lb and is highly efficient, with a lift-to-drag ratio of around 18, but the pilot cannot sit down and a blade strike would be catastrophic, Moore says. Here are NASA videos of both concepts ...
[© 2014 Penton]

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