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Sikorsky Firefly (defunct)


Firefly (defunct)
Sikorsky Aircraft
Stratford, Connecticut, USA

Founded on March 5, 1923, Sikorsky Aircraft, a Lockheed Martin Company, is an American aircraft manufacturer based in Stratford, Connecticut, USA. Sikorsky Aircraft was established by aviation pioneer Igor Sikorsky and was among the first companies in the world to manufacture helicopters for civilian and military use. United Technologies Corporation purchased Sikorsky in 1929 and then in November 2015, Sikorsky was sold to Lockheed Martin.

NOTE: If anyone has a clear picture of the Firefly information graphic and would allow us to post it on this web page, will you please email news@evtol.news with your picture? Thanks.

The Sikorsky Firefly is a modified Schweizer S-300C announced on July 26, 2010 at AirVenture 2010 in Oshkosh, Wisconsin, USA, as a technology demonstration and was said to be a stepping stone to successful electric helicopters. Sikorsky had been working on the project for more than two (2) years and has never revealed the cost of the project.

There are 300 battery cells, installed in two battery packs (150 cells in each pack) located on each side of the helicopter, weighing 1,170 pounds (530 kg) and were manufactured by Gaia Power Technologies based in Germany. U.S. Hybrid, with several offices in the USA, modified a land vehicle's electric motor and built a 190 hp (142 kW) electric motor custom-made for the helicopter. The modifications of the electric engine included adding an additional 40 horsepower, provided consistent 3,200 RPM and used forced air cooling instead of water cooling. Engineers at Eagle Aviation Technologies, based in Virginia, USA, modified the airframe and motor mount, then installed the motor and digital controller for the helicopter.

The Sikorsky testbed figures showed huge improvements in efficiency. The main rotor output is 76.3% efficient in the electric version versus 25.5% for a Sikorsky 76-D luxury helicopter running two (2) Pratt & Whitney PW210S turboshaft engines on JetA fuel. The other notable comparison is heat loss, where the electrical system loses just 15% compared to 73.4% on the 76-D helicopter. They used software to slow the electric engine, to mimic a gas-powered engine to help the pilot and the rotor's bearings, apparently on start-up, during flight and shut-down.

Sikorsky also noted that this electrically powered helicopter simplifies the complexity of the propulsion system by reducing the quantity of moving parts, reduces heat loss, increases reliability, reduces noise inside and outside the helicopter, reduces vibration, has no emissions and reduces direct operating costs. Sikorsky estimated that with one pilot only, it could fly for 12 to 15 minutes at a top speed of 92 mph (148 km/h). If the batteries lost their power, the helicopter could still autorotate and the helicopter pilot could safely land the rotorcraft in any open space. The aircraft was never flown.

The Sikorsky Firefly has been called the world's "first all-electric helicopter" but never was flown. However, a French-based company flew the world's first all electric helicopter named Solution F with a crewed tethered flight on August 4, 2011. The first crewed untethered hover flight for the Solution F helicopter was made on August 12, 2011. In 2017, Sikorsky has been involved in the early development of an aircraft referred to as the VERT. In 2023, Sikorsky announced the program for its Hybrid-Electric Demonstrator (HEX) aircraft for advanced air mobility (AAM).


  • Aircraft type: Electric helicopter demonstrator
  • Piloting: 1 pilot, no passengers
  • Maximum speed: 92 mph (148 km/h)
  • Maximum flight time: 15 minutes
  • Maximum takeoff weight: 2,050 lb (930 kg)
  • Propellers: 3-bladed rotorblade
  • Electric motors: 1 electric motor
  • Maximum horsepower: 190 hp (141.6 kW)
  • Power source: 2 lithium ion batteries, 370 volts, battery weight: 1,170 lb (530 kg)
  • Fuselage: Aircraft aluminum alloy
  • Windows: Helicopter bubble-type canopy
  • Tail: 1 tail rotor
  • Landing gear: Fixed skid landing gear
  • Safety features: In case of loss of a power or motor failure, the Firefly can autorotate and land to safety.

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