Lord has completed diagnostic testing of the active vibration control (AVC) system for the Hindustan Aeronautics (HAL) Dhruv advanced light helicopter.

Cary, North Carolina-based Lord carried out a two-phase testing process of the active damping system. The first phase involved ground vibration response tests as well as measurement of ground run-up and flight vibrations of the Dhruv airframe. Following a data review, Lord proposed three solutions for trial. The second phase involved flight demonstrations of the proposed prototype systems and Lord says early results indicate vibration reduction.

The AVC system installed on the Dhruv employs active Frahm dampers to monitor and reduce vibration in the fuselage generated by the main rotor and the rotor aerodynamics. The control systems use microphones or accelerometers to monitor vibration conditions, and employ actuators to cancel vibrations and speakers to cancel noise.

Lord supplies the main and tailrotor elastomeric bearings and isolators for the helicopter's current pylon isolation system. Deliveries of Dhruvs to the Indian armed forces began early last year.

Source: Flight International