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The basic philosophy of a model rocket motor is too have a solid fuel that provides a large amount of thrust in a relatively short amount of time. This is needed in order to accomplish the task of accelerating the car to a speed that can maintain a duration of flight (as short as it may be).
The Rocket Motor:
The Rocket Motor is broken up into 5 different sections... (The engine burns from the left to the right.)
The Propellant is what creates the thrust or push, that a rocket has. It is made out of a solid fuel containing mostly nitrocellulose and nitroglycerine. The power of the motor can be classified by the letter on the side of the motor; A, B, C, D, E, F, or G, each letter up is twice as powerful as the preceding.
The Total Impulse of a motor, is the maximum amount of thrust the motor expels. This is measured in Newton Seconds, or Pounds of Thrust.
| Engine Type | Total Impulse |
| 1/2 A | 0.626-1.25 |
| A | 1.26-2.50 |
| B | 2.51-5.00 |
| C | 5.01-10.00 |
| D | 10.01-20.00 |
| E | 20.01-40.00 |
The Delay Phase is the burning time in which nothing happens, usually allowing the model rocket too coast upwards and too complete its arc.
The Ejection Charge is what projects the Clay Retaining Cap into the recovery system, which in effect pushes it up and out of the rocket. Thus allowing the parachute to shoot out and provide a soft landing.
In our case however, the entire Delay Phase/Ejection Charge provided more of a hazard then a help... When you are propelling a car and not a rocket, a parachute is not needed. However even though a parachute is not onboard, the Ejection Charge is still present. This makes a very dangerous situation for the launch team. The motor which is securely tied down, would sometimes eject itself out of the rear of the rocket... making it in hence and aerial time bomb/shotgun.
The Secondary part too launch process is too actually ignite the motor...
Too accomplish requires two things:
The first is the Igniter (wire with paper on it). This is the article that glows red hot and generates the ignition. The igniter is pushed into the center of the rocket motor. Then afterwards is held in place by the blasting cap (pink object), which is pushed in on top of it, pressing it to the wall of the rocket motor.
The second item needed for ignition is the Launch Controller. This is what triggers the ignition of a launch, it works as a sort of dead short to the igniter. It provides power to the igniter which shorts the batteries creating the heat described above. The ignition process is controlled by a button, and a safety pin which disables the controller during preflight preparation. The alligator clips (left of picture) are attached to the ends of the igniter wires.
