Aerodynamic Characteristics of NACA 0012 Airfoil Section at Angles of Attack From 0 deg to 180 deg

The aerodynamic characteristics of the NACA 0012 airfoil section have been obtained at angles of attack from 0 deg to 180 deg. Data were obtained at a Reynolds number of 1.8 x 10exp 6 with the airfoil surfaces smooth and with roughness applied at the leading and trailing edges and at a Reynolds number of 0.5 x 10exp 6 with the airfoil surfaces smooth. The tests were conducted in the Langley low-turbulence pressure tunnel at Mach numbers no greater than 0.15. After the stall with the rounded edge of the airfoil foremost, a second lift-coefficient peak was obtained at an angle of attack of about 45 deg initial and second lift-coefficient peaks were also obtained with the sharp edge of the airfoil foremost. The application of roughness and a reduction of the Reynolds number had only small effects on the lift coefficients obtained at angles of attack between 25 deg and 125 deg. A discontinuous variation of lift coefficient with angle of attack was obtained near an angle of attack of 180 deg at the lower test Reynolds number with the airfoil surfaces smooth. At a Reynolds number of 1.8 x 10exp 6, the drag coefficient at an angle of attack of 1800 was about twice that for an angle of attack of 0 deg. The drag coefficients obtained at an angle of attack of 90 deg at a Reynolds number of 1.8 x 10exp 6 were 2.08 and 2.02 with the airfoil surfaces in a smooth and in a rough condition, respectively the drag coefficient obtained at an angle of attack of 90 deg and a Reynolds number of 0.5 x 10exp 6 with the airfoil surfaces smooth was 1.95. These values compare favorably with the drag coefficient of about 2.0 obtained from the literature for a flat plate of infinite aspect ratio inclined normal to the flow.