Consider the data for the NACA 2412 airfoil. Calculate the lift and moment about the quarter chord (per unit span) for this airfoil when the angle of attack is 4^{\circ} and the freestream is at standard sea level conditions with a velocity of 50 ft/s. The chord of the airfoil is 2 ft.
Consider the data for the NACA 2412 airfoil. Calculate the lift and moment about the quarter chord (per unit span) for this airfoil when the angle of attack is 4^{\circ} and the freestream is at standard sea level conditions with a velocity of 50 ft/s. The chord of the airfoil is 2 ft.
Dynamic pressure q_{\infty}=\frac{1}{2}\rho _{\infty}V_{\infty}^{2}=\frac{1}{2}\times0.002377\times50^{2}=2.97\;lb/ft^{2}.Fo r NACA 2412 airfoil coefficient of lift c_{l}=0.64,c_{m,c/4}=-0.036.
Lift per unit span {L}’=q_{\infty}sc_{l}=2.97\times2\times1\times0.64=3.80\;lb/span
Moment about the quarter chord {M}’=q_{\infty}scc_{m,c/4}=2.97\times2\times1\times2\times\left ( -0.36 \right ) \\=-0.428\;ft/lb per unit span.
