Canada's National Research Council (NRC) is seeking an industrial partner with which to complete development of an active cabin-noise control system now under test. The NRC hopes to "commercialise" the technology during a third phase of the development programme, which would include flight tests on a Bombardier de Havilland Dash 8, planned to begin later this year.

Two phases have been completed, including a ground demonstration with a Dash 8 fuselage. While existing systems counter cabin noise by broadcasting "anti-noise" using loudspeakers, the new approach uses piezoelectric actuators bonded to the fuselage "-to stop noise entering the cabin", says Dave Zimcik, group leader for aerostructures at the NRC's structures, materials and propulsion laboratory in Ottawa. Actuators are located where the propeller flowfield strikes the fuselage, and operated in response to noise and/or vibration sensors.

The NRC system reduces sound levels throughout the cabin, he says, unlike anti-noise systems which reduce the noise peaks but can increase sound levels elsewhere. Overall cabin noise reductions exceeding 10dB have been measured in the demonstration.

The NRC has been working so far with Ontario-based actuator developer Sensor Technology and de Havilland, but needs an industrial partner to develop the system for commercial application. Talks are under way with interested companies, Zimcik says. He adds that "de Havilland wants this as fast as possible" for the new Dash 8-400 and for possible retrofit.

Source: Flight International