First consider whether a spinning cylinder could be an alternative for an airfoil in an aircraft. To study this, consider the classical symmetric NACA airfoil 0012. We discussed this airfoil in class when we compared the results of the thin airfoil theory that we developed with the actual performance of this airfoil. This comparison is shown in Fig. 4.25 in the textbook, which illustrates the experimental and theoretical coefficients of lift and moment for this airfoil. Recall that theoretical values are based on the expressions that we derived in class for the symmetric airfoils. 2.4 2.0- NACA 0012 airfoil Eq. (4.33) 1.6 1.2 0.8 I 0.4 . 0 -0.4- -0.8- Eq. (4.41) Cm,c/4 0 -0.1 -0.2 Re 3.0 x 106- -0.3 Re 9.0 X 106 -0.4 -1.2 -1.6 1 -24-16-8 0 8 16 24 32 a, degrees