The point (or line) at which the forces on a wing or other body appear to act is known as the aerodynamic centre. In reality this effect is the sum of the pressure distribution over the whole of the wing. Both lower and upper surfaces, caused by the wing’s influence on the local air velocities and the resultant local static pressure changes. As we saw in Chapter 2, the effect of a wing is to reduce the static pressure below the suction side, the more cambered lower surface (in the racecar context), and to raise the static pressure of the air over the upper, pressure side of the wing. The result of this is that both downforce and, unfortunately, drag are produced, and there will be much more on this as we go through this chapter.