Page 455 - PPL-engelsk 2025

Principles of flight

Bernoulli's principle deals with pressure and states that the static pressure on the

top of the wing decreases as the dynamic pressure increases.

This results in the generated lift.

Remember, about two-thirds of the lift comes from the top of the wing.

Around a symmetric profile, with no

angle of attack, there will be no
resulting lift.

Lift is only generated when a

symmetric profile has an angle of

attack.

Most aerobatic aircraft use symmetric or nearly symmetric wing profiles. This
allows for better inverted flight.

5.3.6.2 Stagnation point

When the airflow splits at the leading edge of the wing, part of the air moves over

the wing, while another part passes

underneath. There is a point where the air

"stands still."

This is called the stagnation point.

When the angle of attack increases, the

stagnation point moves further down the

leading edge of the wing.

The blue arrows in the diagram show the

stagnation point.

Flight Theory PPL(A)(UL)/LAPL Henning Andersen, Midtjysk Flyveskole© 2025 455