Bell officially unveiled its electrically distributed anti-torque (EDAT) system via its Facebook page February 20, but has been operating it on a Bell 429 flying testbed aircraft since May 2019 and applied for a related patent in 2017. EDAT significantly reduces helicopter noise, augments power to the main rotor, and simplifies maintenance by replacing the tailrotor with a series of four ducted fans embedded in the vertical stabilizer.
Each fan is powered by its own electric motor and inputs to the system are controlled via fly-by-wire. EDAT eliminates the need for tailrotor mechanical systems, including driveshafts and gearboxes.
Bell, which has been flight testing EDAT at its Mirabel, Quebec facility, teased it was working on an electrically-powered anti-torque system back in 2017 when it unveiled a mock-up of FCX concept helicopter. That design used electrically-driven vectored thrust in the tailboom to provide anti-torque.
On EDAT, Bell worked with Safran, one of its announced partners on its Nexus 4EX eVTOL urban air taxi program. That aircraft uses a series of four ducted fans to provide thrust. Using electric power to provide tailrotor thrust has long been a topic of investigation for helicopters. In 2017, researchers at Italy’s L’Aquila University evaluated it for an Airbus EC130.