Page 491 - PPL-engelsk 2025

Principles of flight

This causes a torque to the right towards the starting position.

Directional stability can be

increased with arrow-shaped
wings, as this design further

increases the amount of drag

on a forward-moving wing and

thus increases directional

stability.

5.7.5.1 Lateral center (Lc)

When aircraft designers design aircraft, a lot of thought is given to stability. An

important point is the point at which wind from the side or a sideways

movement of the aircraft acts.

The lateral center is the point at

which a wind directly into the side

of an aircraft will act.

A rearward lateral center provides directional stability.

Directional stability is achieved by having the lateral center behind the center of

gravity.

A high placed lateral center provides lateral stability.

Lateral stability is stability around the aircraft's longitudinal axis.

Lateral stability is improved by ensuring that the lateral center is higher than the

center of gravity.

A V-shape on the wing can move Lc higher up. Larger rudders or fins will move

Lc back.

Flight Theory PPL(A)(UL)/LAPL Henning Andersen, Midtjysk Flyveskole© 2025 491