11. Stability and center of gravity

As we all know every body has a certain weight because of Earth's gravity.
Now imagine that all the gravity which is pulling the body down is concentrated
is a single point, called center of gravity. Position of this point determines
the RC plane's stability. Usually the center of gravity is located between 1/2 and 2/3 of the wing's
width. Position of center of gravity is very important, because the RC model is rotating around the center of gravity. If it is not positioned correctly the plane will do all kinds of acrobatics.
Related to all of this, stability can be defined as a characteristic of a RC plane. It is its ability to return into the normal flight position.
There are more kinds of stability. In order for a RC plane to fly correctly it should have three kinds of stability:
1. pitch stability, prevents uncontrollable rotation around horizontal axis. It is accomplished
with the horizontal stabilizer.
2. Roll stability, prevents uncontrollable rolls, usually accomplished by the v-shape if the
wing
3. Yaw stability, prevents uncontrollable rotation around the vertical axis, accomplished with
the vertical stabilizer.