NASA Langley Research Center, in collaboration with Boeing and Lockheed Martin, has developed a new external acoustic liner for aircraft noise reduction. While the acoustic liner can be placed on any external aircraft surface, one attractive application is for open-rotor noise reduction. Airframe manufacturers are considering open rotor engines for future aircraft designs as they provide significant fuel savings. However, open rotor engines have no nacelle and thus, do not allow the use of conventional nacelle liners for noise abatement. This technology strategically places acoustic liners on the external surface of the aircraft to reduce such engine noise.

The liner technology can be applied to wind turbines. This photo shows NASA researchers testing a turbine in a wind tunnel.

This technology is an evolution of acoustic liners developed for engine noise abatement that typically are located inside nacelles. The acoustic liners described here can be outfitted on external surfaces and in tight spaces. Three initial areas of the aircraft have been considered as part of an aircraft configuration incorporating an open-rotor propulsion system. The three areas where the liner configurations were applied were under the rotor, on the upper surface of the elevon, and on the surface of a strut.

NASA is actively seeking licensees to commercialize this technology. Please contact The Technology Gateway at This email address is being protected from spambots. You need JavaScript enabled to view it. to initiate licensing discussions. Follow this link for more information: here .


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This article first appeared in the July, 2017 issue of Tech Briefs Magazine.

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