Accession Number : ADA316869

Title :   Full-Scale S-76 Rotor Performance and Loads at Low Speeds in the NASA Ames 80- by 120-Foot Wind Tunnel. Volume 1.

Descriptive Note : Technical memo.,

Corporate Author : NATIONAL AERONAUTICS AND SPACE ADMINISTRATION MOFFETT FIELD CA AMES RESEARCH CENTER

Personal Author(s) : Shinoda, Patrick M.

PDF Url : ADA316869

Report Date : APR 1996

Pagination or Media Count : 238

Abstract : A full-scale helicopter rotor test was conducted in the NASA Ames 80- by 120-Foot Wind Tunnel with a four- bladed S-76 rotor system. Rotor performance and loads data were obtained over a wide range of rotor shaft angles-of-attack and thrust conditions at tunnel speeds ranging from 0 to 100 kt. The primary objectives of this test were (1) to acquire forward flight rotor performance and loads data for comparison with analytical results; (2) to acquire 8-76 forward flight rotor performance data in the 80- by 120-Foot Wind Tunnel to compare with existing full-scale 40- by 80-Foot Wind Tunnel test data that were acquired in 1977; (3) to evaluate the acoustic capability of the 80- by 120-Foot Wind Tunnel for acquiring blade vortex interaction (BVI) noise in the low speed range and compare BVI noise with in-flight test data; and (4) to evaluate the capability of the 80- by 120-Foot Wind Tunnel test section as a hover facility. The secondary objectives were (1) to evaluate rotor inflow and wake effects (variations in tunnel speed, shaft angle, and thrust condition) on wind tunnel test section wall and floor pressures; (2) to establish the criteria for the definition of flow breakdown (condition where wall corrections are no longer valid) for this size rotor and wind tunnel cross- sectional area; and (3) to evaluate the wide-field shadow- graph technique for visualizing full-scale rotor wakes. This data base of rotor performance and loads can be used for analytical and experimental comparison studies for full-scale, four-bladed, fully articulated rotor systems. Rotor performance and structural loads data are presented in this report.

Descriptors :   *HELICOPTER ROTORS, *WIND TUNNEL TESTS, *DYNAMIC LOADS, TEST AND EVALUATION, VELOCITY, DATA BASES, ANGLES, FLIGHT TESTING, EXPERIMENTAL DATA, INTERACTIONS, STRUCTURAL PROPERTIES, LOADS(FORCES), COMPARISON, GRAPHS, FACILITIES, VORTICES, BLADES, LOW VELOCITY, WAKE, WALLS, SHAFTS(MACHINE ELEMENTS), FLOW, RANGE(EXTREMES), LEVEL FLIGHT, AREA COVERAGE, THRUST, HOVERING, SHADOWS, CORRECTIONS.

Subject Categories : Fluid Mechanics
      Jet and Gas Turbine Engines
      Helicopters

Distribution Statement : APPROVED FOR PUBLIC RELEASE