Electric motors provide lots of torque—exactly the sort of twisting action needed to turn rotor blades. Mr Billing's team have therefore fitted one of the firm's AS350 light helicopters with such a motor, and some lithium-ion batteries to power it. They are now testing the arrangement to work out how much power is needed to keep the craft aloft during the transition to autorotation, and during flaring. Mr Billig thinks Euro copter will be able to offer the system commercially in about a year's time.
That raises the question of whether it might be feasible to build an all-electric helicopter. At the moment, the answer is no. As with cars, the amount of charge a battery can hold is insufficient for robust, everyday use of the vehicle without the security blanket of an internal combustion engine. But batteries are improving, and if they were good enough then an electrically powered helicopter would (like an electric car) be a more elegant solution to the problem of locomotion than the serial explosions that keep an internal-combustion engine ticking over.
