Stability and Control

skillfulbuyerUrban and Civil

Nov 16, 2013 (3 years and 9 months ago)

75 views

Rotational

Motion

Stability and Control

An aircraft is
stable

if it returns to its initial equilibrium
flight conditions when it is perturbed. There are two main
types of aircraft instability:


Stability and Control

An aircraft with
static instability
uniformly

departs from

an equilibrium condition

An aircraft with
dynamic instability
oscillates about the

equilibrium condition with increasing amplitude.

There are two modes of aircraft
control:
one moves the
aircraft between equilibrium states, the other takes the
aircraft into a non
-
equilibrium (accelerating) state.


Control is directly opposed to stability.

Time = 0.0

Time = 1.0

Time = 2.0

Aircraft encounters gust


Nose pitches up

cg

Tail Force

Airflow Direction

Longitudinal Static Stability

Tail Force

Tail Force

Resulting Motion

Lateral Static Stability

Resulting
Motion

Weight

Dihedral Angle

Lift Vectors

Weight

Aircraft rolls
slightly to the right

View Downstream

Time = 0.0

Time = 1.0

Time = 2.0

Dihedral Angle

Lift Vectors

Weight