<P> The Lift discussed in this article is mainly in relation to airfoils, although marine hydrofoils and propellers share the same physical principles and work in the same way, despite differences between air and water such as density, compressibility, and viscosity . </P> <P> An airfoil is a streamlined shape that is capable of generating significantly more lift than drag . A flat plate can generate lift, but not as much as a streamlined airfoil, and with somewhat higher drag . </P> <P> There are several ways to explain how an airfoil generates lift . Some are more complicated or more mathematically rigorous than others; some have been shown to be incorrect . For example, there are explanations based directly on Newton's laws of motion and explanations based on Bernoulli's principle . Either can be used to explain lift . </P> <P> An airfoil generates lift by exerting a downward force on the air as it flows past . According to Newton's third law, the air must exert an equal and opposite (upward) force on the airfoil, which is the lift . </P>

Where does the greatest amount of lift occur on an aerofoil