02/28/2026
What is airfoil?
The shape is comparable to a bird wing, which is shaped to have a greater curve on top than on the bottom. This basic shape drew the attention of many early aviators.
In order to produce upper force, the curve on top of the wing actually has a bigger role than the bottom. The curve on top forces air to travel at a greater velocity. And, at a greater velocity, air is in a thinner state, leaving far less resistance for wings to travel upward as wind hits the bottom.
In contrast, if wings were completely flat, it would take a considerable amount of power to keep the plane in the air, and even then, the likelihood of a problem is not even debatable. A random change in direction would overwork the wings and engines, slowing them to dangerous levels. Why? Air on top of the wings is separating, canceling out the lift on the bottom. When this happens, pilots call it a stall, but a normal person might see it as face planting.
Stalls happen even when wings have the airfoil shape, but it would require some effort or simply horrible judgement to ever get into one. With the curve on top, air is much more likely to flow smoothly from front to back. But if the wing is angled too high in relation to the wind, it would produce the same effect as the flat surface.
This is why pilots are trained not only to understand airfoil shapes, but to feel pending stalls and to shift the wings into an appropriate flow with the wind.