AVweb’s Look At Sikorsky’s All-Electric Helicopter


A company that does gas-electric auto conversions in California, a technology integration company, and Sikorsky have teamed up to prove the manned electric helicopter by way of Project Firefly. The Firefly is actually an S300C two-seat bare-bones helicopter. Sikorsky has had the S300C’s original Lycoming HIO 360 engine swapped out for a permanent magnet electric motor from U.S. Hybrids — a company that will gladly convert your automobile, too. Systems integrated by Eagle Technologies, LLC, help the Firefly’s motor deliver about 10 hp more than the Lycoming’s 190 hp but has the helicopter carry 1,000 pounds worth of lithium ion batteries to do it. The batteries put the Firefly within about 150 pounds of the S300C’s 2150-pound max gross weight and offer about 15 minutes worth of flying time in return. But that’s not the point. We spoke to Jonathan Hartman of Sikorsky’s innovations division to further explain.

The Firefly is not meant to corner the market on manned electric helicopters. What it is meant to do is help Sikorsky better understand how they might be doing that in the future. Flight tests are expected to begin later this year and development will continue behind the scenes. To keep things simple, the Firefly’s tailrotor is conventionally driven by a shaft connected to the helicopter’s main electric motor. In future designs it is possible that the shaft could be replaced with a lighter motor at the tail linked by wires to the flight controls and main motor controller. Clear advantages of electric power are reduced vibration and noise, plus a vastly reduced parts count and maintenance requirements for the powerplant. Clear challenges include weatherproofing and the current limits of battery technology.