ACTIVE CANCELLATION OF INTERIOR AND EXTERIOR PROPELLER DRIVER AIRCRAFT NOISE USING AN EXTERIOR SOURCE

WE PROPOSE TO DEVELOP, FOR AIRCRAFT DEPLOYMENT, AN ACTIVE CANCELLATION TECHNIQUE THAT HAS SHOWN PROMISE IN PRELIMINARYLABORATORY TESTING. THE SYSTEM CONSISTS OF A PROVEN CANCELLATION ALGORITHM FOR REPETITIVE NOISE THAT USES A SYNCH PULSE FROM THE ENGINE, A HIGH POWER SOUND SOURCE MOUNTED NEAR THE PROPELLER THAT ADAPTS A SOURCE TECHNOLOGY DEVELOPED BY OUR STAFF, AND AN INNOVATIVE CONCEPT FOR DETECTING THE PROPELLER NOISE IMPINGING ON THE FUSELAGE. THE SYSTEM CONCEPT IS TO PROVIDE ANTI-NOISE WHICH CANCELS THE PROPELLER RADIATED NOISE BEFORE IT REACHES THE FUSELAGE OR GROUND. THE SYSTEM DEVELOPMENT REQUIRES R&D AND INTEGRATION OF THREE TECHNICALLY DIVERSE COMPONENTS (SOURCES, RECEIVERS, AND SIGNAL PROCESSORS). OUR STAFF HAS A STRONG BACKGROUND IN ALL THREE AREAS. FOR THE FIRST STAGEOF THE DEVELOPMENT, WE WILL COMPLETELY CHARACTERIZE THE PROPELLER NOISE FIELD. THIS WILL ALLOW US TO DETERMINE SYSTEM AND COMPONENT PERFORMANCE SPECIFICATIONS. THEN PRELIMINARY DESIGNS WILL BE TECHNICALLY AND ECONOMICALLY EVALUATED, AND A HARDWARE DEVELOPMENT PLAN CREATED. THE SYSTEM WILL THEN BE BUILT AND TESTED IN FLIGHT. THE SYSTEM POTENTIALLY HAS SIGNIFICANT ECONOMIC IMPACT SINCE AN ACTIVE SYSTEM IS MUCH LIGHTER WEIGHT THAN PASSIVE NOISE CONTROL. IT WILL ALSO RESULT IN A VERY POSITIVE REDUCTION OF ENVIRONMENTAL NOISE LEVELS.