A PRESENTATION OF MEASURED AND CALCULATED FULL-SCALE ROTOR BLADE AERODYNAMIC AND STRUCTURAL LOADS
UNITED TECHNOLOGIES CORP STRATFORD CT SIKORSKY AIRCRAFT DIV
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A test of a set of Sikorsky CH-34 rotor blades was conducted in the NASAAmes full-scale wind tunnel at speeds of 110 to 175 knots. One blade of the set was instrumented to measure differential chordwise pressures, as well as flapwise, chordwise and torsional stress. The test results are presented, two- and three-dimensional pressure distributions are compared, and a correlation of airloads and blade stresses is made with a flexible blade aeroelastic theory, including both uniform and variable inflow assumptions. Correlation of airloads and stresses with theoretical results was generally good. Inclusion of variable inflow improved correlation on both advancing and retreating sides of the disk at speeds as high as 175 knots, but the need for a more precise wake treatment is indicated. There is also evidence of a requirement for including lifting surface effects in the calculation at the advancing blade tip. A comparison of some of the wind tunnel data with flight test results shows good agreement.
- Fluid Mechanics