As the lift of an airfoil increases, what happens to the drag?

As the lift of an airfoil increases, the drag typically increases as well. This is due to several aerodynamic principles. When an airfoil generates more lift, it usually operates at higher angles of attack or speeds. Both of these conditions contribute to an increase in induced drag, which is directly related to the amount of lift being generated.

Induced drag arises due to the formation of vortices at the wingtips, a byproduct of generating lift. As lift increases, these vortices become more pronounced, leading to greater induced drag. In addition, as the angle of attack increases to generate more lift, other forms of drag, such as profile drag, may also increase due to more airflow separation and friction along the wing's surface.

While it's important to note that at certain speeds and angles, drag might fluctuate, the general trend within the operational limits and conditions of an airfoil is that increasing lift will lead to an increase in drag. This relationship is fundamental to understanding the balance of aerodynamic forces at play during flight.