First Manned Electric-Powered Helicopter Flight Achieved
September 8, 2011 – Electrical and aerospace engineer Pascal Chretien has done what the entire Sikorsky corporation is still trying to accomplish: the first untethered electric-powered manned helicopter flight. Last month Chretien hovered his coaxial design helicopter 1 meter above the ground for more than two minutes. Approached by the French automotive research company Solution F to build the helicopter, in 12 months Chretein designed, built, and flew the aircraft, which is powered by lithium batteries and brushless DC motors.
To be fair Chretien’s approach to electric helicopter flight is much different than Sikorsky’s Firefly, which debuted at EAA AirVenture 2010. Sikorsky is attempting to fly a helicopter through conventional means, which involves a main rotor and tail rotor to counteract main rotor torque. This approach requires much more power, according to Gizmag’s detailed report on Chretien’s successful attempt. Sikorsky does have experience with coaxial helicopter designs, as it recently set records with its X-2.
Chretien chose the coaxial contra-rotating twin-rotor design to save weight and reduce required power output. The design also eliminates the need for a tail rotor, which, according to Chretien, uses 8 to 10 percent of the power required, especially in a hover.
Other unique features of the aircraft are the flight controls, which employ a combination of power variation and a mechanical tilt system of the tail fin to control yaw, conventionally inputted through rudder pedals. Chretien steers the craft by using a cyclic control that varies blade angle, while the collective is controlled by an overhead handlebar system that weight-shifts the aircraft beneath the rotating blades.
The unorthodox approach is not without risk, as Chretien tells Gizmag that, after years of flying conventional helicopters, he had to build a weight-shift simulator to practice: "In case of crash I stand good chances to end up in kebab form."