Solar plane

(States Twitter)-An electric aircraft is an aircraft that runs on electric motors rather than internal combustion engines, with electricity coming from fuel cells, solar cells, ultracapacitors, power beaming, and/or batteries.

Currently flying electric aircraft are mostly experimental demonstrators, including manned and unmanned aerial vehicles. Electrically powered model aircraft have been flown since the 1970s, with one report in 1957.

History

In 1883 Gaston Tissandier was the first to use electric motors in airship propulsion. The following year, Charles Renard and Arthur Krebs flew La France with a more powerful motor.

Nikolai Tesla envisaged using electrically powered aircraft, powered by beams from the ground or the ionosphere.

Electric motors have been used for model fixed-wing aircraft since from at least 1957, with a challenged claim from 1909.

In 1964 William C. Brown demonstrates on CBS News with Walter Cronkite a model helicopter that receives all of the power needed for flight from a microwave beam.

In 2007 the non-profit CAFE Foundation held the first Electric Aircraft Symposium in San Francisco.

Experimental projects

1970s and 1980s

[edit]Sunrise

The 27 lb (12 kg) unmanned AstroFlight Sunrise, the result of an ARPA contract, made the world's first solar-powered flight from Bicycle Lake, a dry lakebed on the Fort Irwin Military Reservation, on 4 November 1974. The improved Sunrise II flew on 27 September 1975 at Nellis AFB.

Solar Riser

The world’s first official flight in a solar powered, man carrying aircraft took place on April 29, 1979. The Mauro Solar Riser was built by Larry Mauro and was based on the UFM Easy Riser biplane hang glider. The aircraft used photovoltaic cells that produced 350 watts at 30 volts, which charged a Hughes 500 helicopter battery, which in turn powered the electric motor. The aircraft was capable of powering the motor for 3 to 5 minutes, following a 1.5 hour charge, enabling it to reach a gliding altitude.

Solar One

The Solar-Powered Aircraft Developments Solar One was designed by David Williams under the direction of Freddie To, an architect and member of the Kremer prize committee and produced by Solar-Powered Aircraft Developments. A motor-glider type aircraft originally built as a pedal powered airplane to attempt the Channel crossing, the airplane proved too heavy to be successfully powered by human power and was then converted to solar power, using an electric motor driven by batteries that were charged before flight by a solar cell array on the wing. The maiden flight of Solar One took place at Lasham Airfield; Hampshire on June 13, 1979, one day after Brian Allen had successfully pedalled the Gossamer Albatross across the English Channel.

Gossamer Penguin and Solar Challenger

The Gossamer Penguin, a smaller version of the human powered Gossamer Albatross was completely solar powered. A second prototype, the Solar Challenger, flew 262 km (163 mi) from Paris to England. On 7 July 1981, the aircraft, under solar-power, flew 163 miles from Cormeilles-en-Vexin Airport near Paris across the English Channel to RAF Manston near London, flying for 5:23. Designed by Dr. Paul MacCready the Solar Challenger set an altitude record of 14,300 feet.

Solair 1

The human piloted Solair 1 was developed by Günther Rochelt and based on a Farner canard design.It employed 2499 wing-mounted solar cells giving an output of between 1.8 kW (2 hp) and 2.2 kW (3 hp). The aircraft first flew at Unterwössen, Germany on 21 August 1983.It flew for 5 hours and 41 minutes, "mostly on solar energy and also thermals". The aircraft is now displayed at the German Museum in Munich.The newly developed piloted Solair II made its first flight in May 1998 and further test flights that summer but the propulsion system overheated too fast.Development stopped when Günther Rochelt suddenly died in September 1998.

NASA Pathfinder and Helios

NASA's Pathfinder and Helios were a series of solar and fuel cell system-powered unmanned aircraft. AeroVironment, Inc. developed the vehicle under NASA's Environmental Research Aircraft and Sensor Technology program.

1990s.

Sunseeker

In 1990 the solar powered airplane Sunseeker successfully flew across the USA, piloted by Eric Raymond.It used a small battery charged by solar cells on the wing to drive a propeller for takeoff, and then flew on direct solar power and took advantage of soaring conditions when possible.

The Sunseeker II, built in 2002, was updated in 2005-2006 with a more powerful motor, larger wing, lithium battery packs and updated control electronics. As of Dec, 2008 it was the only manned solar powered airplane in flying condition and is operated regularly by Solar Flight.In 2009 it became the first solar-powered aircraft to cross the Alps, 99 years after the first crossing of the Alps by an aircraft.

Lange Antares 20E

A Lange Antares 20E in a hangar

The Lange Antares 20E is a self-launching motor glider with a 42-kW electric motor and SAFT VL 41M lithium-ion batteries. The motor actuates 2-blade fixed pitch propeller. It can climb up to 3,000 meters with fully charged cells. After launch it can function as a conventional, though heavy, glider. As of January 2010, over 50 had been built.

2010s

Cessna 172

In July 2010 Cessna announced it was developing an electrically-powered Cessna 172 as a proof-of-concept in partnership with Bye Energy. Cessna CEO Jack Pelton stated that the project reflects "encouraging news for the future of mainstream general aviation." Pelton pointed out "the electric power plant offers significant benefits, but there are significant challenges to get there."

PC-Aero Elektra One

The Elektra One is a development of a commercial electric aircraft design by PC-Aero of Germany. The single seat composite aircraft is expected to have its first flight in early 2011. The Elektra One is powered by a 21 hp (16 kW) electric motor and is expected to have an endurance of three hours, with a 100 mph (161 km/h) top speed.

The company is planning a whole line of aircraft including a version of the Elektra One with longer wings and built-in solar panels and an aerobatic version with double Elektra One's power and airframe strength. The company is also planning two and four seat developments.

Pipistrel Taurus Electro G2

First made available commercially in February 2011, the Taurus Electro G2 is a two-seat self-launching sailplane. The 40 kW (54 hp) engine powers the aircraft from internally-mounted lithium batteries for a 17-minute climb, after which the engine is retracted and the aircraft then soars as a sailplane.

Design and operation of electric aircraft

Regenerative flight

A design concept has been put forward for soaring-type aircraft called regenerative soaring. In this approach, a propeller, using symmetrical blade sections, would be used as a turbine to recharge stored energy when the aircraft encounters an updraft.At high altitudes, the energy available from vertical atmospheric motion within a thermal can exceed available solar power by a factor of ten or more.