United States Patent (19) 11 Patent Number: 4,836,469 Wagenfeld 45 Date of Patent: Jun
United States Patent (19) 11 Patent Number: 4,836,469 Wagenfeld 45 Date of Patent: Jun. 6, 1989 (54) SYSTEM FOR REDUCING AIRCRAFT NOISE 4,723,626 2/1988 Carr et al. ........................... 181/213 AND HUSHKT OTHER PUBLICATIONS (75 Inventor: Robert E. Wagenfeld, New York, "Silencing an Executive Jet Aircraft', Noise Control N.Y. Engineering, vol. 5, No. 2, Sep.-Oct. 1975, J. R. Brooks, 73) Assignee: Walsan Partners Limited Partnership, et al. New York, N.Y. "Quieting the JT3D Powered 707", Sound and Vibra (21) Appl. No.: 55,635 tion, vol. 8, No. 2, Feb. 1974, J. Woodall. Primary Examiner-Galen Barefoot (22 Filed: May 29, 1987 Assistant Examiner-Rodney Corl 51) Int. Cl........................ B64D 29/00; B64D 33/04 Attorney, Agent, or Firm-Cooper & Dunham 52) U.S. Cl. ................................... 244/1 N; 181/213; [57] ABSTRACT 181/220; 181/222; 181/296 58) Field of Search ................. 244/1 N, 55; 181/213, A system is provided for existing three-engine jet air 181/220, 222, 296 craft to reduce the noise levels at take-off and landing in order to meet governmental noise regulations. The (56) References Cited system is particularly suitable for 727-200 aircraft hav U.S. PATENT DOCUMENTS ing three JT8D engines. A hush kit is formed of the 3,002,341 10/1961 Muzzy et al. ....................... 181/220 modified components for installation in existing air 3,237,891 3/1966 Wotton ................................. 244/55 planes. 4,379,191 4/1983 Beggs et al. .......................... 52/806 4,456,204 6/1984 Hapke ................................... 244/55 4 Claims, 4 Drawing Sheets U.S.
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