This lecture Ir. N. Timmer starts off by recapping the forces on a theoretical 2D wing, and the effect of compressibility. He then finds an expression for the critical pressure coefficient and explains the cause of the effects occurring in the transonic flight region. He then starts talking about tip vortices generated by finite wings and explains the induced drag caused by this. Next he explains the effect of the finite wing on the lift curve, and derives an expression for the slope of the lift curve of a finite wing. Next he explains how sweep affects the aerodynamic properties of the wing and can be used to deal with the critical mach number. Finally he talks about high lift devices and how they are used and what their effects are.