The Farnborough-based Noise Test Facility operated by British technology company QinetiQ (Stand A19, Hall 1) will be re-opened later this year following a multi-million-pound refit funded by Rolls-Royce and the UK Department of Trade and Industry.

The NTF, with one of the largest anechoic chambers in the world, provides high fidelity and quality in noise measurement. "The refurbished facility should have a significant impact on research and development in the area of aircraft noise reduction," says Richard Pinker, QinetiQ capability leader for aircraft noise.

The main anechoic chamber measures 26m X 26m and stands 14m in height. 360mm-thick reinforced-concrete walls prevent any external noise entering the chamber, which is lined throughout with 21,000 acoustic deadening wedges.


The refit centres on installation of dedicated air supplies to support the testing of large-scale models of aircraft engine exhaust systems and other airframe components. Other enhancements are designed to address cabin noise at cruise conditions. Under construction is an enclosed Mach 0.8-rated wind tunnel with a cross-section of around 1sq m. It will accommodate engine exhaust models of around 100mm in diameter.

"One of the most promising areas of investigation in the facility may yield reductions in jet mixing noise of up to 4dB," says Pinker. The technique involves the fixing of castellated or serrated aerodynamic devices at the rear of the exhaust nozzle to control the mixing of the hot jet exhaust and the bypass stream with the ambient air.

Source: Flight Daily News