Full-Scale Wind-Tunnel Tests of a PCA-2 Autogiro Rotor

This paper presents the results of force tests on an airflow surveys near a PCA-2 autogiro rotor in the N. A. C. A. full-scale wind tunnel. The force tests were made at three pitch settings and several rotor speeds; the effect of fairing protuberances on the rotor blade was determined. Induced downwash and yaw angles were determined at two tip-speed ratios in a plane 1 1/2 feet above the path of the blade tips. The results show that the maximum L/D of the rotor cannot be appreciably increased by increasing the blade pitch angle above about 4.5° at the blade tip; that the protuberances on the blades cause more than 5 percent of the total rotor drag; and that the rotor center-of-pressure travel is very small.