Static and wind tunnel model tests for the development of externally blown flap noise reduction techniques
- Author:
- Pennock, A. P.
- Published:
- Mar 17, 1975.
- Physical Description:
- 1 electronic document
- Additional Creators:
- Swift, G.
Marbert, J. A. - Access Online:
- hdl.handle.net
- Restrictions on Access:
- Unclassified, Unlimited, Publicly available.
- Summary:
- Externally blown flap models were tested for noise and performance at one-fifth scale in a static facility and at one-tenth scale in a large acoustically-treated wind tunnel. The static tests covered two flap designs, conical and ejector nozzles, third-flap noise-reduction treatments, internal blowing, and flap/nozzle geometry variations. The wind tunnel variables were triple-slotted or single-slotted flaps, sweep angle, and solid or perforated third flap. The static test program showed the following noise reductions at takeoff: 1.5 PNdB due to treating the third flap; 0.5 PNdB due to blowing from the third flap; 6 PNdB at flyover and 4.5 PNdB in the critical sideline plane (30 deg elevation) due to installation of the ejector nozzle. The wind tunnel program showed a reduction of 2 PNdB in the sideline plane due to a forward speed of 43.8 m/s (85 kn). The best combination of noise reduction concepts reduced the sideline noise of the reference aircraft at constant field length by 4 PNdB.
- Collection:
- NASA Technical Reports Server (NTRS) Collection.
- Note:
- Document ID: 19750010105.
Accession ID: 75N18177.
NASA-CR-134675.
LG74ER0170. - Terms of Use and Reproduction:
- No Copyright.
- Access Online:
- hdl.handle.net
View MARC record | catkey: 15740933