A wing of span 15 m with elliptic lift distribution produces 80 kN lift at 90 m/s in air of density 1.2 kg/m³. Find induced angle of attack in degrees, to 2 decimals.
For elliptic loading, $\alpha_i=C_L/(\pi AR)=L/(\pi q b^2)$ radians. Dynamic pressure is q = 1.2(90²)/2 = 4860 Pa. Hence $\alpha_i=80000/[\pi(4860)(15^2)]=0.02329$ rad = 1.33°. Wing area cancels between CL and aspect ratio.
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