A subsonic transport aircraft has a tapered, untwisted sweptback wing with straight leading and trailing edges....

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A subsonic transport aircraft has a tapered, untwisted sweptback wing with straight leading and trailing edges. The tail uses a symmetrical airfoil with no local moment about its own aerodynamic center. The narrow fuselage may be neglected in the consideration of total lift and moment and the engine thrust is aligned through the mass centre. The following numerical data is supplied. S=253 m² 5.87 m Xac=5.5 m (back from wing apex) St=70 m² [ 16.75m (back from wing ac) Wing area Wing mean aerodynamic chord Wing aerodynamic center Tail area Tail ac location Wing lift-curve slope Wing local moment coefficient Tail lift-curve slope Tail incidence angle Downwash angle at zero wing angle-of-attack Downwash angle change with angle-of-attack Static margin for typical cruise flight a=4.2 (CL per rad) (CM)=-0.025 a, 4.0 (C, per rad) i 2.0 (down from wing ZLL) to=0.5 En = 0,25 (rad/rad) (ha-h)=0.06 (a) Calculate the (elevator-fixed) neutral point location with respect to the wing apex. (b) Calculate the wing angle-of-attack (from the wing ZLL) required to hold the aircraft in pitch balance with zero elevator deflection. A subsonic transport aircraft has a tapered, untwisted sweptback wing with straight leading and trailing edges. The tail uses a symmetrical airfoil with no local moment about its own aerodynamic center. The narrow fuselage may be neglected in the consideration of total lift and moment and the engine thrust is aligned through the mass centre. The following numerical data is supplied. S=253 m² 5.87 m Xac=5.5 m (back from wing apex) St=70 m² [ 16.75m (back from wing ac) Wing area Wing mean aerodynamic chord Wing aerodynamic center Tail area Tail ac location Wing lift-curve slope Wing local moment coefficient Tail lift-curve slope Tail incidence angle Downwash angle at zero wing angle-of-attack Downwash angle change with angle-of-attack Static margin for typical cruise flight a=4.2 (CL per rad) (CM)=-0.025 a, 4.0 (C, per rad) i 2.0 (down from wing ZLL) to=0.5 En = 0,25 (rad/rad) (ha-h)=0.06 (a) Calculate the (elevator-fixed) neutral point location with respect to the wing apex. (b) Calculate the wing angle-of-attack (from the wing ZLL) required to hold the aircraft in pitch balance with zero elevator deflection.