Consider the DC-3A/C. Just outboard of the engine nacelle, the airfoil chord length is 4.7 m. At cruising velocity, the moments per unit span at this airfoil location are M_(c/4)=-1452Nm M_(LE)=-4357Nm. Calculate the lift per unit span and the location of the center of pressure on the airfoil.

To calculate the lift per unit span and the location of the center of pressure on the airfoil, we can use the following equations:<br /><br />1. Lift per unit span (L):<br />L = (M_c/4 - M_LE) / (c/4 - LE)<br /><br />2. Location of the center of pressure (CP):<br />CP = (M_c/4 * LE + M_LE * c/4) / (M_c/4 + M_LE)<br /><br />Given:<br />- Chord length (c) = 4.7 m<br />- Moments per unit span:<br /> - M_c/4 = -1452 Nm<br /> - M_LE = -4357 Nm<br /><br />Now, let's calculate the lift per unit span (L) and the location of the center of pressure (CP).<br /><br />1. Lift per unit span (L):<br />L = (-1452 Nm * 0.25 m - (-4357 Nm * 0.75 m)) / (0.25 m - 0.75 m)<br />L = (-363 Nm + 3266.25 Nm) / (-0.5 m)<br />L = 2903.25 Nm / -0.5 m<br />L = -5806.5 N/m<br /><br />2. Location of the center of pressure (CP):<br />CP = ((-1452 Nm * 0.25 m) + (-4357 Nm * 0.75 m)) / ((-1452 Nm) + (-4357 Nm))<br />CP = (-363 Nm + (-3266.25 Nm)) / (-1452 Nm - 4357 Nm)<br />CP = (-3629.25 Nm) / (-5809 Nm)<br />CP = 0.624 m<br /><br />Therefore, the lift per unit span is -5806.5 N/m, and the location of the center of pressure on the airfoil is 0.624 m.