# Subsonic Wings

## What Makes a Wing Work?

Let's use a wing to help get a better understanding of lift at subsonic speeds. With a typical subsonic wing, the upper surface is more curved than the lower surface.

The curved upper surface constricts the flow of air more than the flatter lower surface, causing the air above the wing to speed up more than the air below. The faster the air speeds up, the lower its pressure becomes. So the faster moving air above has less pressure than the slower moving air below. (Remember, this relationship between pressure and speed is called Bernoulli’s principle.) The higher air pressure below pushes the wing up—lift.  Any further increase in the speed of the air will increase the difference in pressure and increase the lifting force on the wing.

Check out how NASA is experimenting with the way we build wings in this video about the Blended Wing Body.

Q:

## Paper airplanes don't have the "classic" airfoil shape, so how do they fly?

A:

They use the angle of attack of their flat wings to create lift. The angle of attack is the angle at which oncoming airflow meets the airfoil. Lift is generated from the same low pressure (Bernoulli effect) as with a curved wing although not nearly as much.

# Watch a Video

## Lift: Bernoulli’s Principle

Find out how Bernoulli's principle helps explain lift.

## Did You Know?

The shape of a flying disc (or Frisbee) is an airfoil in cross-section. The airfoil shape allows it to fly by generating lift as it moves through the air while rotating.

## Pop Quiz

Which of the following are examples of airfoil shapes?

A) Wings
B) Vertical tail surfaces
C) Propellers
D) All of the above