Soru
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.
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4.7
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Elit · 8 yıl öğretmeni
Uzman doğrulaması
Cevap
To calculate the lift per unit span and the location of the center of pressure on the airfoil, we can use the following equations:1. Lift per unit span (L):L = (M_c/4 - M_LE) / (c/4 - LE)2. Location of the center of pressure (CP):CP = (M_c/4 * LE + M_LE * c/4) / (M_c/4 + M_LE)Given:- Chord length (c) = 4.7 m- Moments per unit span: - M_c/4 = -1452 Nm - M_LE = -4357 NmNow, let's calculate the lift per unit span (L) and the location of the center of pressure (CP).1. Lift per unit span (L):L = (-1452 Nm * 0.25 m - (-4357 Nm * 0.75 m)) / (0.25 m - 0.75 m)L = (-363 Nm + 3266.25 Nm) / (-0.5 m)L = 2903.25 Nm / -0.5 mL = -5806.5 N/m2. Location of the center of pressure (CP):CP = ((-1452 Nm * 0.25 m) + (-4357 Nm * 0.75 m)) / ((-1452 Nm) + (-4357 Nm))CP = (-363 Nm + (-3266.25 Nm)) / (-1452 Nm - 4357 Nm)CP = (-3629.25 Nm) / (-5809 Nm)CP = 0.624 mTherefore, 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.