Noise measurements of model jet-augmented lift systems

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086 0 ‡aNAS 1.14:D-6710
088 ‡aNASA-TN-D-6710
100 1 ‡aGibson, Frederick W.
245 1 0 ‡aNoise measurements of model jet-augmented lift systems / ‡cFrederick W. Gibson.
246 3 ‡aNASA TN D-6710
260 ‡aWashington, D.C. : ‡bNational Aeronautics and Space Administration : ‡b[For sale by the Clearinghouse for Federal Scientific and Technical Information, Springfield, Virginia 22151], ‡c1972.
300 ‡a34 p. : ‡bill. ; ‡c27 cm.
490 0 ‡aNASA technical note ; ‡vD-6710
504 ‡aIncludes bibliographical references (p. 8).
520 ‡aNoise measurements were obtained on models of jet-augmented lift systems which are currently being considered for use on proposed short takeoff and landing vehicles. These configurations included a conventional internally blown flap, an augmenter wing, an externally blown flap, and modifications of these basic concepts. The tests were conducted in the Langley anechoic noise facility at zero forward speed with cold air jets. The conventional internally blown flap exhibited lower noise levels than the augmenter wing and the externally blown flap at the same pressure ratios, being of the order of 8 dB or more at the lowest pressure ratio and of the order of 20 dB at the highest pressure ratio of the tests. The data also indicated that for the conventional internally blown flap, there may be an optimum gap size (other than zero) between the turning lip and the flap leading edge from the standpoint of minimum noise generation or admittance. Increasing the trailing-edge thickness of the plain internally blown flap produced no appreciable change in the overall sound pressure level or frequency spectral content in the range of the tests. The data indicated that at a position on the ground directly under the jet exit, the externally blown flap and the augmeter-wing overall noise levels are comparable to each other throughout the pressure range of the tests.
538 ‡aMode of access: Internet.
650 0 ‡aLift (Aerodynamics)
650 0 ‡aAerodynamic noise.
650 0 ‡aNoise control.
650 0 ‡aShort take-off and landing aircraft.
710 2 ‡aLangley Research Center.
710 1 ‡aUnited States. ‡bNational Aeronautics and Space Administration.
CID ‡a011445094
DAT 0 ‡a20101111085653.0 ‡b20141009010000.0
DAT 1 ‡a20141112165512.0 ‡b2020-04-05T18:00:18Z
DAT 2 ‡a2020-04-05T17:30:02Z
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