1. Rocket Stability

2. Forces Acting on a Rocket
Gravity
Thrust
Air Drag

3. Inertia
The tendency of all bodies to resist any change in motion

4. Newton’s Laws
Law of Inertia: A body at rest stays at rest, a body in motion stays in motion unless there is another force acting on that body.
Law of Acceleration:: Motion is proportional to the forces exerted
Law of Reaction: For every action there is an opposite and equal reaction

5. Center of Gravity CG
The Center of Gravity or CG is the balancing point of a free body that can rotate around all axis. It is an imaginary point at which all mass seems to be concentrated.

6. Center of Pressure CP
Center of Pressure is a point where all air pressure forces converge or act.

7. CG -CP Relationship

8. Inherently Stable Rocket
CG must be forward of CP or CP must be aft of CG

9. Changing CG to make a Stable Rocket
Use Lighter Motor
Add Weight to Nosecone
Make rocket Longer

10. Changing CP to make the Rocket Stable
Use Larger Fins
Increase the number of Fins
Make Nose Cone Longer

11. Stability Characteristics
A positive stability rocket will have a stable flight
A neutral stability rocket might have a stable flight
a negative stability rocket will not have a stable flight

12. Flight paths