Page 454 - PPL-engelsk 2025

Principles of flight

The total lift acts at the center of pressure, shown by the large black vertical

arrow.

As the angle of attack increases, lift increases.

At the same time, the pressure pattern around the wing changes, causing the

center of pressure to move forward along the wing.

The opposite occurs when the angle of attack is reduced, causing the center of
pressure to move backward.

In the figure below, you can see how the center of pressure "shifts" when the

angle of attack increases.

The red curved line represents pressure

distribution.

At the top, we see the center of pressure

at small angles of attack.

At the bottom, we see the pressure

distribution at higher angles of attack.

The center of pressure moves forward

due to the changed lift pattern.

5.3.6.1 Pressure distribution around profiles

There are many different ways to explain the lift. It can be explained both through

Newton's and Bernoulli's principles.

Newton's principle of action and reaction can be applied, as we have created a

downward airflow behind the profile. This will produce a force of equal size but
opposite direction on the wing.

Flight Theory PPL(A)(UL)/LAPL Henning Andersen, Midtjysk Flyveskole© 2025 454