Item Details

Measured Noise of Model Fan-Under-Wing and Fan-on-Flap Jet Flap Configurations

by John F. Groeneweg and Gene L. Minner
Format
Book; Government Document; Online; EBook
Published
Washington, D.C. : National Aeronautics and Space Administration ; [Springfield, Va. : For sale by the National Technical Information Service], 1972.
Language
English
Series
NASA Technical Note
Summary
Noise measurements were made on two jet flap systems proposed for STOL aircraft. In one case a 14.0-cm- (5.5-in.-) diameter fan was mounted under the wing such that the exhaust impinged on downwardly deflected flap segments. In the other case, the fan was located on the upper surface of the flap such that fan and flap moved as a unit, with no exhaust impingement. Results for takeoff and approach fan speeds and flap deflections were used to estimate STOL airplane perceived noise levels. Internally generated noise directivity corresponded with fan axis orientation for the fan-on-flap, but no consistent redirection of internal noise was observed with changes in flap angle for the fan-under-wing. With the fan-on-flap arrangement, the wing shielded some fan inlet noise from the ground. Since no impingement of the exhaust on solid surfaces occurred, the external noise was jet noise alone. In contrast, for the fan-under-wing, the jet/flap interaction noise dominated the external noise except at angles near the jet axis even with no flap deflection. If internal noise is reduced by fan design and acoustic treatment, the jet/flap interaction noise will dominate.
Description
55 p. : ill. ; 27 cm.
Mode of access: Internet.
Notes
  • Prepared at Lewis Research Center.
  • Cover title.
  • Bibliography: p. 14.
Series Statement
NASA technical note ; NASA TN D-6781
Logo for No Copyright - United StatesNo Copyright - United States
Technical Details

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    a| Groeneweg, John F. q| (John Frederick), d| 1937-
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    a| Measured noise of model fan-under-wing and fan-on-flap jet flap configurations c| by John F. Groeneweg and Gene L. Minner.
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    a| Washington, D.C. : b| National Aeronautics and Space Administration ; a| [Springfield, Va. : b| For sale by the National Technical Information Service], c| 1972.
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    a| 55 p. : b| ill. ; c| 27 cm.
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    a| NASA technical note ; v| NASA TN D-6781
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    a| Prepared at Lewis Research Center.
    500
      
      
    a| Cover title.
    504
      
      
    a| Bibliography: p. 14.
    520
      
      
    a| Noise measurements were made on two jet flap systems proposed for STOL aircraft. In one case a 14.0-cm- (5.5-in.-) diameter fan was mounted under the wing such that the exhaust impinged on downwardly deflected flap segments. In the other case, the fan was located on the upper surface of the flap such that fan and flap moved as a unit, with no exhaust impingement. Results for takeoff and approach fan speeds and flap deflections were used to estimate STOL airplane perceived noise levels. Internally generated noise directivity corresponded with fan axis orientation for the fan-on-flap, but no consistent redirection of internal noise was observed with changes in flap angle for the fan-under-wing. With the fan-on-flap arrangement, the wing shielded some fan inlet noise from the ground. Since no impingement of the exhaust on solid surfaces occurred, the external noise was jet noise alone. In contrast, for the fan-under-wing, the jet/flap interaction noise dominated the external noise except at angles near the jet axis even with no flap deflection. If internal noise is reduced by fan design and acoustic treatment, the jet/flap interaction noise will dominate.
    538
      
      
    a| Mode of access: Internet.
    650
      
    0
    a| Short take-off and landing aircraft x| Noise.
    650
      
    0
    a| Jet flaps (Airplanes) x| Noise x| Measurement.
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    1
      
    a| Minner, Gene L. q| (Gene Logan), d| 1942-
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    a| United States. b| National Aeronautics and Space Administration.
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    a| Lewis Research Center.
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    b| UIU c| UIUC d| 20141113 s| google u| uiug.30112106883710 y| 1972 r| pd q| bib

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