SBIR-STTR Award

Foster-Miller proposes to develop an easily retrofitted, Active Noise Cancellation System (ANCS) for reducing the external noise of large transport and multifunction aircraft during takeoff and landing. Billions of dollars have been spent relocating people from around airports in which the average noise level is 65dB or greater (1). Therefore any easily retrofitted improvements that can be made to reduce the external noise footprint during take-off and landing of aircraft, without harming the aircraft performance, will result in large cost savings for the U.S. Navy. Aircraft structural modifications or hushkitted aircraft have been tried with mixed noise abatement results. The Navy has a need to develop a noise reduction system that is cost-effective, easily retrofitted onto the current turboprop and turbofan aircraft, and that is low in weight and power consumption. Foster-Miller proposes to use an active treatment in the shroud of the engine inlet to control the reflected sound emanating from the vanes of the inlet fan. Phase II will focus on conducting a limited field demonstration of prototype. Our team includes experts in acoustic modeling and will include an aircraft engine manufacturer. (P-030132) Benefits Successful development of easily retrofitted acoustic noise reduction technology would have broad application to commercial aviation. The implementation of this technology would save billions of dollars that would have been spent relocating people away from the airport’s >65dB zone. The development of this technology would also result in greater breadth in determining takeoff and landing profiles. The reduction of noise complaints would improve the public relations between the airport and the surrounding community. Keywords active, noise, turboprop , cancellation, turbofan, retrofitted

Aircraft noise abatement, particularly in the near vicinity of airports, is a serious and expensive problem for both military and civilian air fleets. Previous noise abatement efforts such as engine replacement, structural modifications, or the addition of a Hushkit, have yielded mixed results. These methods are not particularly effective at reducing noise and most also adversely impact the performance capabilities of the aircraft. With the costs of noise abatement climbing, it is imperative that a cost-effective solution to the jet noise problem be developed. Optimally, the solution would be effective for development aircraft and could be incorporated into the current fleet. Foster-Miller’s innovative Active Noise Cancellation System (ANCS) is a novel and cost-effective solution to this challenging problem. Our ANCS controls inlet engine noise over a broad band of frequencies in a narrow and adaptable geometric range of the omni-directional source. The narrow geometric location of the ANCS device is cost-effective and directly affects the particular noise source, which directionally impacts civilian areas around the airfield on takeoff. In Phase I, we performed experiments and analyses validating the principles supporting our concept. Herein, we propose the development and testing of a scaled, full-functional ANCS for inlet aircraft engine noise. (P-040436)

Keywords:
Active Noise Control, Smart Materials, Structural-Acoustic Analysis, Turbofan