Model Wind Tunnel Tests of a Reverse Velocity Rotor System
FAIRCHILD INDUSTRIES INC FARMINGDALE NY FAIRCHILD-REPUBLIC DIV
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A one-seventh scale model reverse velocity rotor system was manufactured and tested with the goal of substantiating the results that had been predicted for this system in previous analytical studies. The 8 ft diameter 4 bladed hydraulically powered model rotor was provided with remote operation of the controls and shaft angle. Tests were conducted in the 12 ft pressure wind tunnel at NASA Ames during June and July 1972. The tests did not cover the whole range of conditions desired, but results were obtained at advance ratios from 0. 3 to 2.46 and at tunnel speeds up to 350 knots. Significant results of the tests were the freedom of the rotor from instability, and the ability to trim the rotor laterally and longitudinally under all conditions. Reasonable agreement was found between the measured performance of the model rotor and that predicted using the results of two-dimensional wind tunnel tests made on three reversible airfoil sections of the model rotor blade. It is recommended that further tests be performed with this model to expand the envelope of test conditions, particularly to include testing with two-per-rev control angle input.