This technology is a new type of aircraft pylon design for noise control. A pylon connects the engine to the airframe of an aircraft. This design uses air passing through the pylon to actively disrupt the jet engine exhaust stream after it exits the engine, disrupting and redistributing the axial and azimuthal distributed sources of jet noise from the aircraft.

The pylon system redistributes noise sources within jet exhaust to enhance shielding of jet noise by the airframe surface (when applied to aircraft with engines above wings or fuselage).

For use on aircraft, the air intake would be on the pylon at an aerodynamically advantageous location. The delivery system would consist of pipes, a pump or pressure regulator, and a plenum chamber. The air is piped through the internal pylon structure by a pump and to the plenum chamber. The injection site for the most common embodiments would be the shelf of the pylon (adjacent to the core nozzle flow), and the trailing edge of the pylon. The objective of the injection is to alter the trajectory of the core nozzle flow, thereby impacting how the core and fan streams mix and the resulting overall trajectory. The injection site on the trailing edge has the objective of minimizing the wake of the pylon by injecting higher pressure and velocity air through the active aircraft pylon trailing edge injector. At cruise conditions, injection from the pylon trailing edge can also reduce the pylon’s drag contribution to the total aircraft drag.

The technology can be retrofit into existing aircraft pylon designs. It reduces noise where jet exhaust interacts with control surfaces (flaps, ailerons, etc.). It also redistributes noise sources within jet exhaust to enhance shielding of jet noise by the airframe surface (when applied to aircraft with engines above the wings or fuselage). This technology can be used in commercial aircraft, business jets, and UAVs.

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: http://technology.nasa.gov/patent/TB2016/LAR-TOPS-179 .


NASA Tech Briefs Magazine

This article first appeared in the November, 2016 issue of NASA Tech Briefs Magazine.

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