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

When the lift of an airfoil increases, the drag typically increases as well. This relationship is primarily due to the characteristics of aerodynamic forces acting on the airfoil. As lift is generated, particularly at higher angles of attack, the airflow over the wing becomes more turbulent, leading to increased viscous (or profile) drag.

However, there is a nuanced aspect to the relationship between lift and drag. While induced drag (a component of drag that is associated with the production of lift) increases in tandem with lift, this increase can be influenced by various factors like the shape of the airfoil and operating conditions. The total drag on an airfoil will generally increase when there is an increase in lift because of the balancing act of lift production and the resultant drag forces.

In certain specific conditions or with certain airfoil designs, it’s possible to see variations in drag, but the prevailing understanding in aerodynamics is that an increase in lift correlates with an increase in drag, primarily due to the induced drag component.