A -- NASA RESEARCH ANNOUNCEMENT (NRA-98-LREC-1) -- ACTIVE NOISE CONTROL Background: The Advanced Subsonic Technology (AST) Noise Reduction Program at NASA s Lewis Research Center and Langley Research Center is developing technology to reduce engine noise for subsonic aircraft. Active Noise Control is a technique that can be used to reduce fan noise from turbofan engines. There have been several successful tests that show how Active Noise Control can be used to reduce tone noise from fans. As a next step toward developing this technology, NASA wants to experimentally demonstrate reduction of tone noise for a "cut-on" fan over a wide range of fan speeds. NASA LeRC anticipates issuing a draft NASA Research Announcement for Industry comment on or around April 3, 1998. Scope: Proposals should include a concise plan that describes how an Active Noise Control system will be used to reduce at least the BPF (Blade Passing Frequency) tone (to broadband levels) resulting from a "cut-on" fan stage design. A "cut-on" fan stage has a sufficiently low number of stator vanes sucho that noise resulting from fan/stator interaction contains a strong tone at the blade passing frequency. An experiment is being solicited that uses the Active Noise Control system in either model scale or engine validation tests. The Active Noise Control system should use components that have good potential for eventual flight vehicle applications. The system should be capable of reducing the fan tones over a wide range of fan speeds. The figure of merit for noise reduction will be based on Perceived Noise Levels (PNL) for a typical flight path of a subsonic aircraft near airports, with emphasis on community noise reduction. Proposals will be evaluated based on: 1) technical merit, 2) knowledge of aeroacoustics (relative experience), 3) degree of teaming with other AST participants, 4) degree of technology transfer to all AST participants, 5) level of cost sharing, 6) participation of Small Disadvantaged Businesses, and 7) ability to communicate and manage technical programs (past performance). The duration of a resulting contract(s) will be three (3) years starting in FY99 (October, 1998). NASA anticipates having a total of $1.5M available for this work ($500K in FY99, $500K in FY00, and $500K in FY01). Offerors may propose the use of Government facilities; however, can be used, but the cost of using the facilities should be included as a part of the proposal. For information regarding facility availability and cost, or for any technical questions, please contact Dennis L. Huff by phone at (216) 433-3913 or by e-mail at Dennis.L.Huff@lerc.nasa.gov, or you may contact Jorge L. Sotomayor by phone at (216) 433-8303 or by e-mail at Jorge.L.Sotomayor@lerc.nasa.gov. For contractual or business questions, please contact John P. Kuminski by phone at (216) 433-2453 or by e-mail at John.P.Kuminski@lerc.nasa.gov. Multiple awards will be considered. WEB: Click here for the latest information about this notice, http://nais.nasa.gov/EPS/LeRC/date.html#NRA-98-LERC-1. E-MAIL: John P. Kuminski, John.P.Kuminski@lerc.nasa.gov.

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