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SST Technology Follow-On Program - Phase 2. Noise Suppressor/Nozzle Development. Volume 5. Advanced Suppressor Concepts and Full Scale Tests

Descriptive Note:

Final rept. on Task III

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The goal of this program was to develop and demonstrate an engine exhaust system suitable for use on a commercial supersonic transport which would allow the airplane to meet FAR Part 36 takeoff and sideline noise requirements. A series of model-scale jet noise suppressor test programs and a design feasibility study were conducted to identify the exhaust system design which would meet this goal. A model-scale test and a full-scale test of a boilerplate version of the final design were conducted statically to demonstrate thrust performance and noise suppression characteristics. Full-scale test results were limited to a jet velocity of 2300 fps due to engine operating limits, while model-scale results were extended beyond the design velocity of 2550 fps. The full-scale suppressor system test achieved 15.8 PNdB sideline jet noise reduction for 0.75 static gross thrust loss at v sub j 2300 fps. Model-scale tests of the same system show that the jet noise suppression should increase to 16.8 PNdB at v sub j - 2550 fps. Forward flight effects during climb-out are predicted to degrade the suppressor performance to a value of 15 PNdB noise reduction for 7 net thrust loss. Consequently, it is shown that the application of such a suppressor system to the Boeing B2707-300 SST configuration would achieve FAR Part 36 sideline noise levels. Further, it is shown that such an installation would allow an approximately 7.5 increase in the airplanes maximum takeoff weight, thereby improving its economic and mission flexibility.

Subject Categories:

  • Transport Aircraft
  • Jet and Gas Turbine Engines

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