We are used to seeing one compensating propeller in the tail of a helicopter, driven by a gearbox, cardan shaft and hub, to compensate for the reactive torque. But Bell Helicopters has developed an innovative concept, replacing the tail rotor with 4 electric motors and 4 closed-type rotors. The system is called EDAT (electrically distributed anti-torque).

The system is controlled by the pilot, as in a conventional helicopter with a pedal, but the propellers are driven not by rods, as with a conventional tail rotor, but by an electric remote system.

The uniqueness of the system is that each of the propellers is driven by its own independent electric motor, therefore the rotation speed is regulated independently of each other. Electric motors drive electric generators driven by the helicopter engines.

According to Bell specialists, the control system is significantly safer compared to the usual compensating propeller, since if it fails, the helicopter loses control. With the help of electric rotors, the system will allow the pilot to safely fly the helicopter even if three of the four rotors fail, which significantly affects the safety of flights.

Two generators are powered by a shaft that goes to the tail rotor, as in a conventional version of the helicopter. Even if both engines fail, energy will be transmitted to the shaft from the rotors rotating due to autorotation, so the generators will continue to operate and the helicopter will not lose control.

The electronic control system allows you to turn with absolute precision, which is extremely important in hover mode and when maneuvering at low speed. Moreover, the helicopter flies sideways stably and obediently.

The control system has been tested on a modified Bell 429 helicopter in Quebec, Canada since May 2019. We are waiting for the results with interest.

05 MAY 2020