Problem 1 (effect of 'plan-form' of wing): en a G 8=260 2 => CDi = KG = Coo Consider an airplane with an Oswald efficiency factor of 0.7. Suppose its plan-form is redesigned to increase the Oswald efficiency factor to 0.8 without changing other parameters such as the parasite drag coefficient or the aspect ratio: AR a. Determine the % change in the minimum drag coefficient. = 6=240 b. Determine the % change in the minimum thrust required to maintain a cruise flight in a fixed altitude. -only place Co/min = W We have seen ' b) = TR= On Dmin is in the dros polo paraunter, K. (C=Co.o +K&) Go, independent = D TR CL/CD fet 333 Min Co = of W , K=//R (6/6)max mex = 4KC0 'R 854507 = use some notation: To.1 T0.8 = = T0.8 K0.8 10.8 0.7 To.7 T07 = K = 0.8 Je (AR) -| 64%