Sikorsky Firefly Electric Helicopter Preview

Last year, during the scorching days of the summer, the helicopter gurus from Sikorsky announced the start of a revolutionary project: the Firefly Electric Helicopter Demonstrator. Introduced at a time when the electric buzz has engulfed the motorized world in its entirety, the Firefly is not intended, for now, to do much of anything. Built only as a “look what we can do” vehicle, the helicopter does however preview the future of aerial transportation in vehicles with no fixed wings, provided that the current trend towards electrification continues, of course. Last week, in the first days of 2010, news of the helo preparing for its first test flight broke. Although no official timetable has been established yet, we took a closer look at the project, limited for now due to the lack of actual data, if worth the effort. WHAT IS THE FIREFLY
The Firefly has not been built from the ground up as an electric helicopter. As most of the systems under research, it has been converted from an existing platform into a new, alternative-powered vehicle.

When it was born, the helicopter came in the form of a S-300C rotating wing bird. The S-300C, advertised by Sikorsky as one of the “finest and most versatile piston-engine rotorcraft,” is usually powered by a Textron Lycoming HIO-360 D1A engine which develops 190 hp, or 141 kw.

The helicopter has a maximum gross weight of 2,050 lbs (930 kg), a maximum speed of 86 knots (159 km/h) and can reach an altitude of 10,800 ft (3,292 m).

The helicopter is being used in a huge number of operations, ranging from personal transportation to military and civilian training, including law enforcement patrol and lift operations.


When creating the electric helicopter demonstrator, the engineers from Sikorsky didn't spend their time modifying the S-300C from the grounds up to become the Firefly. The overall shape of the helicopter was maintained, its purpose likewise and, looked at from the outside, little sets it apart from the units you see flying overhead wearing police logos.

What the engineers focused on was replacing the Lycoming engine altogether. They pulled it out and replaced it with an electric powertrain. The electric motor and digital controller were supplied by US Hybrid, while the lithium ion energy storage system come from Gaia. The little work that has been done at the exterior of the vehicle, including some airframe modifications, as well as the assembly of the demonstrator were conducted by Eagle Aviation Technologies.

The reborn helicopter now comprises an all-electric drive system coupled to a high-density energy storage system (two battery packs, each either side of the helicopter), automated monitoring and alert technologies, as well as brand new and adapted-to-suit the new needs cockpit controls.

From the inside, the pilot will have a whole new image of the plane. The cockpit has been fitted with all the tools required by the pilot to fly the unusual craft, including an LCD monitor which feeds real-time aircraft health information (like temperature or power level) gathered by sensors scattered throughout the Firefly.


The electric drive system is intended to be just as powerful as the usual engine used on the base helicopter. Meant to develop 190 hp, the electric motor is expected to make the Firefly achieve pretty much the same performances as the S-300C. There are, unfortunately, no real data to base assumptions on since, as said, the first test flight is yet to be conducted.

According to the men behind it, the Firefly weighs pretty much within the gross weight limits of the aircraft. The range, a relative concept when it comes to the Firefly, translates so far, according to the estimations of the Sikorsky Innovations engineers, in some 15 minutes of flying time.


As is the case with cars, an electric drivetrain fitted on helicopters could potentially be a lifesaver for both the planet and the operators' budgets. The aircraft is less complex, hence easier to maintain and, because it lacks so many moving parts as an usual helo has, it can reduce vibration and noise made during flight.

The Firefly is being regarded by Sikorsky as only the beginning of a new age in aviation, even if, at this point, no one can say for sure when this new age actually gets here.


As is the case with any electrically propelled vehicle, the Firefly too will be affected by two major downsides: range and recharge time. However, when it comes to recharge time, the problem is less serious as it is in cars, since helicopters are not flown round the clock and can benefit from longer off-duty periods in which to be recharged.

The main disadvantage of an electric helicopter is its range, or how people in the industry like to call it, autonomy. At this point in time, there's little you can do with a helicopter who can only stay in the air for 15 minutes. To make it fly for longer, you would have to add more batteries, but that in turn would send the weight number flying higher than the helicopter itself.

This is why Sikorsky names its helicopter a “demonstrator.” Meaning it shows it can be done, but comes with no promises attached. For now.
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About the author: Daniel Patrascu
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Daniel loves writing (or so he claims), and he uses this skill to offer readers a "behind the scenes" look at the automotive industry. He also enjoys talking about space exploration and robots, because in his view the only way forward for humanity is away from this planet, in metal bodies.
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