An Exploratory Aerodynamic Limits Test with Analytical Correlation

The purpose of the current test program is to produce a new dataset with sufficient documentation to be useful for correlation, development, and refinement of aerodynamic models at high thrust. An aerodynamic limits test was conducted in the 7by 10-Foot Wind Tunnel at Ames Research Center. The objectives of the test were to measure the performance and control loads of the rotor in nominal thrust, lightly stalled, and deep stalled conditions. Advance ratios from 0.15 to 0.35 were tested with data concentrated at an advance ratio of 0.2. Shaft angle was varied from 0 to -2 deg with tip speeds of 310 and 446 ft/sec. Thrust and power measurements were found to be high quality and repeatable at different rotor speeds and shaft angles. Redundant torsion load information recorded with two strain gages on the pitch horns and a gage on the blade showed that the pitch horn gages were consistent while the blade torsion measurement was not. CAMRAD II predictions of thrust and power correlated well with the test data.