MECH $342$ Assignment $9$: Lift & Drag

Q$1.$ A commercial aircraft has a mass of $m=250,000kg,$ has a wing planform area of $A=425m^2,$ a wing aspect ratio of $AR=9\mathrm{.}0,$ a $2$D drag coefficient of $C_{D,2D}=0\mathrm{.}03$ and stall angle of $=12.$

a$)$ Find the minimum flight speed of the aircraft. Assume the lift slope follows the relationship $C_L=2.$ Assume the aircraft is in cruise $($all forces are balanced$).$ Use $=0\mathrm{.}66k\frac{g}{m^3}$ for the density of air.

b$)$ The pilot increases the throttle so that the aircraft accelerates. Find an expression for the acceleration of the aircraft depending solely on the velocity $(V).$ The thrust from the engines is $T=440kN$ and the angle of attack $=2.$

Q$2.$ Using sketches and equations as appropriate, describe the process of boundary layer separation and how it affects the lift and drag over a wing.