ASSESSMENT AT FULL SCALE OF NOZZLE/WING GEOMETRY EFFECTS ON OTW AERO-ACOUSTIC CHARACTERISTICS

The effects on acoustic characteristics of nozzle type and location on a wing for STOL engine over-the-wing configurations are assessed at full scale on the basis of model-scale data. Three types of nozzle configurations are evaluated: a circular nozzle with external deflector mounted above the wing, a slot nozzle with external deflector mounted on the wing and a slot nozzle mounted on the wing. Nozzle exhaust plane locations with respect to the wing leading edge are varied from 10 to 46 percent chord (flaps retracted) with flap angles of 20 (takeoff altitude) and 60 (approach attitude). Perceived noise levels (PNL) are calculated as a function of flyover distance at 152 m altitude. From these plots, static EPNL values, defined as flyover relative noise levels, are calculated and plotted as a function of lift and thrust ratios. From such plots the acoustic benefits attributable to variations in nozzle/deflector/wing geometry at full scale are assessed for equal aerodynamic performance.

  • Corporate Authors:

    Department of the Navy

    The Pentagon
    Washington, DC  USA  20350
  • Authors:
    • Groesbeck, D
    • Vonglahn, U
  • Publication Date: 1979

Media Info

  • Pagination: 31 p.

Subject/Index Terms

Filing Info

  • Accession Number: 00198895
  • Record Type: Publication
  • Source Agency: National Technical Information Service
  • Report/Paper Numbers: NASA-TM-79168
  • Files: TRIS
  • Created Date: Oct 17 1980 12:00AM