1. Principles of Rocketry
Design and Drawing for Production
Mr. Herrling

2. Outline: Newton’s Third Law Solid Fuel Rockets Liquid Fuel Rockets
Water bottle Rockets
Forces on Rockets
Rocket Stability

3. Isaac Newton’s 3rd law of Motion
For every action there is an equal and opposite reaction

4. What is the Action? Solid Fuel Rockets
Fuel in solid form burns and is converted to hot gasses.
Hot gasses expand and create high pressure.
Pressure escapes out nozzle, pushing against air and rocket body equally.
Reaction: Rocket moves forward, as gasses move backwards

5. Gasses Rocket Action Reaction

6. More on Solid Fuel Rockets
Solid-fueled rockets use a fuel and oxidizer in solid form. The fuel and oxidizer are in a powdery or rubbery mixture known as the grain or charge. Once a solid-fueled rocket is ignited, it burns completely. There is no way to stop the combustion or to change the amount of thrust.

7. Liquid Fuel Rockets Work on same basic principles as solid fuel.
Carry liquid fuel and oxygen.
Unlike solid fuel, liquid fuel can be regulated to control thrust.

8. … Liquid Fuel
Used for launches and interplanetary travel, liquid fuel rockets are more versatile than solid rockets because the amount of thrust can be controlled, but they are less reliable than solid rocket engines.

9. Space Shuttle: Liquid Fuel and Oxygen tank feeding Engines
Solid Fuel Rocket Boosters

10. Propulsion
All spacecraft need to reach about 17,500 miles per hour to get into orbit.
Thrust is used to push the spacecraft this fast.
Thrust is produced by burning a rocket fuel with oxygen.
If there is not enough thrust the spacecraft will fall back to earth due to gravity.

11. Our Water Rockets
Instead of hot gasses creating pressure, we use a bike pump and store pressure.
Action: Expelling water from engine bottle (water is forced down)
Reaction: Water resisting against rocket body (Rocket is forced up)

13. Water Rockets Work Like Real Rockets

15. Thrust
Forward motion or thrust can best be described by observing a balloon filled with air. When air is released from the balloon, forces inside the balloon cause it to move to the left.

16. Weight
Weight is the force generated by the gravitational attraction on the rocket.
We are more familiar with weight than with the other forces acting on a rocket, because each of us have our own weight which we can measure every morning on the bathroom scale.
We know when one thing is heavy and when another thing is light

17. Drag
We can think of drag as aerodynamic friction, and one of the sources of drag is the skin friction between the molecules of the air and the solid surface of the moving rocket.
Because the skin friction is an interaction between a solid and a gas, the magnitude of the skin friction depends on properties of both solid and gas.

18. Lift
The lift force (the aerodynamic force perpendicular to the flight direction) is used to overcome the weight.
On a rocket, thrust is used in opposition to weight.
On many rockets, lift is used to stabilize and control the direction of flight.

19. Stability During Flight
The purpose of putting fins on a rocket is to provide stability during flight, that is, to allow the rocket to maintain its orientation and intended flight path.
If a typical amateur rocket was launched without fins, it would soon begin to tumble after leaving the launcher, due to the way that aerodynamic and other forces (such as wind) act upon the rocket, in relation to the forces that are exerted upon the rocket by the motor and by gravity.

20. Stability During Flight…
Think about a dart…
Fins or feathers in the rear act like wind veins and trail behind.
Heavy mass made of metal carriers the momentum.

21. The End…