Because of its simplicity, it is used to describe lift in most flight training manuals. This description focuses on the shape of the wing and prevents one from understanding such important phenomena as inverted flight, power, ground effect, and the dependence of lift on the angle of attack of the wing. The third description, which we are advocating here, we will call the Physical Description of lift. This description is based primarily on Newton's laws. The physical description is useful for understanding flight, and is accessible to all that are curious.
Little math is needed to yield an estimate of many phenomena associated with flight.
This description gives a clear, intuitive understanding of such phenomena as the power curve, ground effect, and high-speed stalls. However, unlike the mathematical aerodynamics description, the physical description has no design or simulation capabilities. The Popular Explanation of Lift Students of physics and aerodynamics are taught that airplanes fly as a result of Bernoulli's principle, which says that if air speeds up the pressure is lowered. Thus a wing generates lift because the air goes faster over the top creating a region of low pressure, and thus lift. This explanation usually satisfies the curious and few challenge the conclusions.