Directional stability

Directional stability
Tags: FAA Pilot's Handbook
Directional stability.

directional stability
The tendency of an aircraft to keep flying the direction its pointed
dirty; dirty up
Extension of gear, hook, flaps, etc. for slow speed flight or landing ...

[edit] Directional stability
For any aircraft to fly without constant correction it must have directional stability in yaw.

Directional stability is associated with the realigning of the longitudinal axis with the flight path (the angle of zero slip) after a disturbance causes the aircraft to yaw out of alignment and produce slip; ...

Directional Stability.-Directional stability has to do with the tendency of an airplane to swerve to - the right or left of its proper course.

This motion exists in any airplane for which the ratio of static directional stability and dihedral effect lies between the limiting conditions for spiral divergences and directional divergence.

The tail fin determines the directional stability.
If a gust of wind strikes the aircraft from the right it will be in a slip and the fin
will get an angle of attack causing the aircraft to yaw until the slip is eliminated.

The angling back of the wings from the centre, to increase directional stability or reduce drag at high speed.
Swept Wing
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directional stability: See yaw-wise stability, 19.6.1
displaced threshold, 12.7.3
distance-measuring equipment (DME), 14.7.4
distance-measuring equipment (DME), 14.3.2
distance: versus angle off course, 14.4.1
distraction, 15.3 ...

Rudder: A vertical moving surface usually hinged to the sternpost of the fin in the tail unit of an aeroplane. Its functions are to provide directional control and to assist directional stability.

See also: Stability, Flight, Speed, Direct, Wing