Accession Number : ADP007530

Title :   Combat Aircraft Noise Reduction by Technical Measures,

Corporate Author : MOTOREN- UND TURBINEN-UNION G M B H MUNICH (GERMANY F R)

Personal Author(s) : Wegner, M. ; Kennepohl, F. ; Heinig, K.

Report Date : APR 1992

Pagination or Media Count : 13

Abstract : The noise of combat aircraft during low level flight is dominated by the jet. Technical noise reduction measures must therefore reduce the specific thrust of the engine. This can be achieved by altering the engine cycle or by using secondary air to increase the mass flow through the nozzle. In the first part the influence of nozzle area, bypass ratio and variable cycle features on the specific thrust of modem fighter engines is shown. The effects on noise, thrust and fuel consumption are discussed. In the second part ejector-mixer nozzles and the aft-fan are considered. Both reduce the jet velocity by entraining air through secondary inlets and expelling it together with the engine's exhaust flow through a common nozzle.

Descriptors :   *LEVEL FLIGHT, *LOW LEVEL, *NOISE REDUCTION, *AIRCRAFT ENGINE NOISE, AIR, AIRCRAFT, CONSUMPTION, CYCLES, EJECTORS, ENGINES, FANS, FLIGHT, FLOW, FUEL CONSUMPTION, FUELS, INLETS, MASS, MASS FLOW, MODEMS, NOISE, NOZZLES, RATIOS, REDUCTION, SECONDARY, THRUST, VARIABLES, VELOCITY, WARFARE, LOW ALTITUDE, GERMANY, FIXED WING AIRCRAFT.

Subject Categories : Acoustics
      Military Aircraft Operations
      Noise Pollution and Control

Distribution Statement : APPROVED FOR PUBLIC RELEASE