Author: Publisher:
ISBN:
Category :
Languages : en
Pages : 198
Book Description
Blade-Mounted Flap Control for BVI Noise Reduction Proof-of-Concept Test
Author: Blade-mounted Trailing Edge Flap Control for BVI Noise Reduction
Author: A. A. HassanBlade-Mounted Flap Control for Bvi Noise Reduction Proof-Of-Concept Test
Author: National Aeronautics and Space Administration (NASA)Publisher: Createspace Independent Publishing Platform
ISBN: 9781722959548
Category :
Languages : en
Pages : 196
Book Description
This report describes a wind tunnel test of the McDonnell Douglas Helicopter Systems (MDHS) Active Flap Model Rotor at the NASA Langley 14- by 22-Foot Subsonic Tunnel. The test demonstrated that BVI noise reductions and vibration reductions were possible with the use of an active flap. Aerodynamic results supported the acoustic data trends, showing a reduction in the strength of the tip vortex with the deflection of the flap. Acoustic results showed that the flap deployment, depending on the peak deflection angle and azimuthal shift in its deployment schedule, can produce BVI noise reductions as much as 6 dB on the advancing and retreating sides. The noise reduction was accompanied by an increase in low frequency harmonic noise and high frequency broadband noise. A brief assessment of the effect of the flap on vibration showed that significant reductions were possible. The greatest vibration reductions (as much as 76%) were found in the four per rev pitching moment at the hub. Performance improvement cam results were inconclusive, as the improvements were predicted to be smaller than the resolution of the rotor balance. Dawson, Seth and Hassan, Ahmed and Straub, Friedrich and Tadghighi, Hormoz Langley Research Center BLADE-VORTEX INTERACTION; WIND TUNNEL TESTS; NOISE REDUCTION; AIRCRAFT CONTROL; FLAPS (CONTROL SURFACES); HELICOPTERS; AEROACOUSTICS; PRESSURE DISTRIBUTION; ACTIVE CONTROL; INTERACTIONAL AERODYNAMICS; VIBRATION EFFECTS; PITCHING MOMENTS; ROTOR DYNAMICS; SURFACE PROPERTIES; ROTOR BLADES; PRESSURE MEASUREMENT; NOISE SPECTRA; ACOUSTIC PROPERTIES; BLADE SLAP NOISE; DEFLECTION; FREQUENCIES; SUBSONIC SPEED; WING TIP VORTICES...
NASA Technical Memorandum
Author: Monthly Catalog of United States Government Publications
Author: Publisher:
ISBN:
Category : Government publications
Languages : en
Pages : 1076
Book Description
Implementation of a Trailing-Edge Flap Analysis Model in the NASA Langley CAMRAD.MOD1/Hires Program
Author: NASA Langley Scientific and Technical Information Output, 1995
Author: Publisher:
ISBN:
Category : Astronautics
Languages : en
Pages : 172
Book Description
This document is a compilation of the scientific and technical information that the Langley Research Center has produced during the calendar year 1995. Included are citations for formal reports, high-numbered conference publications, high-numbered technical memorandums, contractor reports, journal articles and other publications, meeting presentations, technical talks, computer programs, tech briefs, and patents.
Journal of the American Helicopter Society
Author: American Helicopter SocietyPublisher:
ISBN:
Category : Helicopters
Languages : en
Pages : 376
Book Description
Smart Structures and Materials
Author: AIAA Journal
Author: American Institute of Aeronautics and AstronauticsPublisher:
ISBN:
Category : Aeronautics
Languages : en
Pages : 1152
Book Description