Determine the Oswald ef‑ciency factor of a rectangular wing with an AR of 14.
A single-engine trainer aircraft with a wing area of 26 m2 has a ‑xed landing gear with three similar tires. Each tire has a diameter of 25 cm and a thickness of 7 cm. Each tire is connected to the fuselage with a strut with a diameter of 4 cm and a length of 15 cm. The landing gear does not have fairing; determine zero-lift drag coef- ‑cient of the landing gear.