A model aircraft in a wind tunnel with a wing area of 0.9 squaremeters and a chord of .24 meters is subject to a sea level standardairflow at 130 m/sec. The zero-lift moment about thecenter-of-gravity is measured as – 7.8 N m. At a different angle ofattack, the moment about the center-of-gravity is measured as 13.5N m with a lift of 2,650 N.
(A)Calculate the value of the moment coefficient about theaerodynamic center, and the location of the aerodynamic center(relative to the cg).
(B) Lead is added to the tail so that the center-of-gravity isshifted aft by 25% of the chord. Calculate the moment about thecenter-of-gravity with a lift of 3,000N.