1. *
07/16/96
Propulsion
Lab 6
Winter Quarter *

2. Model Rockets: Components*
07/16/96
Model Rockets: Components
Instructor:
A model rocket consists of different types of components needed for successful flight. The fins, nose cone, and body tube have aerodynamic properties needed for flight. The parachute is needed for recovery. The engine provides thrust, and the igniter provides a remote way to launch the vehicle.
Winter Quarter *

3. Model Rocket Engines Instructor:*
07/16/96
Model Rocket Engines
Instructor:
The model rocket engine is ignited by the igniter. The thrust stage of the engine is ignited and the rocket is propelled upward. After the propellent is used up, a delay charge is ignited, which allows the rocket to coast upward for an amount of time until the ejection charge is activated. The ejection charge deploys the recovery system, which is usually a parachute or a streamer that allows the rocket to float to the ground slowly.
Winter Quarter *

4. Model Rockets: Flight Sequence*
07/16/96
Model Rockets: Flight Sequence
Instructor:
The flight sequence allows the rocket to reach it’s peak altitude and be safely recovered, as shown in this drawing.
Winter Quarter *

5. Relationship Between Thrust and Impulse*
07/16/96
Relationship Between Thrust and Impulse
Instructor:
Model rocket engines are designed to provide a certain thrust and impulse. The force per unit time graphs demonstrate thrust and impulse. The curve shows the thrust at any given time. The area under the curve is the impulse. The graph on the right shows the average thrust generated over time. The area under that line is also the impulse.
Winter Quarter *

6. *
07/16/96
Instructor:
This is a thrust-time curve for a typical model rocket. The acceleration is quick, with the peak thrust occurring quickly, and a sustained constant thrust happening for a much longer time. The thrust then drops off quickly. The area under the thrust curve is the impulse. Note that the total burn time is less than 4.5 seconds. 4
Winter Quarter *

7. *
07/16/96
Instructor:
Model rocket engines have a letter-number-number code, such as B6-4. The letter is the total impulse measured in Newton-seconds. A B-type engine has a 5-Newton-second total impulse. The number after that is the average thrust measured in Newtons. In the case of a B6-4 engine, the Average thrust would be 6 Newtons. The last number is the time delay between the end of the thrust phase and the activation of the ejection charge. This is the amount of time the rocket can coast before the recovery system is deployed. In the case of the B6-4 example, the delay is 4 seconds.
Winter Quarter *

8. Typical Curves Instructor:*
07/16/96
Typical Curves
Instructor:
This is a graph of typical hobby model rocket engine thrust curves. This graph usually comes with the engine package. Different curves allow for more flexibility in the size of the rocket, the duration of the flight, and the peak altitude the rocket needs to go.
Winter Quarter *