The rockets have quite a wide cross-section so there is lots of drag – that’s why they ones with smaller motors don’t go very far. The explosion from the motors before they land is designed to push out a parachute. These simple designs don’t have parachutes but it is quite simple to add one.
In a more conventional design the nose cone is pushed out by the small explosion and the whole machine floats gently down to Earth under a parachute. The wadding stops the heat of the explosion from melting the parachute. The shock cord is usually slightly elastic and stops the rocket breaking apart when the motor pushes out the nose cone.
We are going to try firing a similar design of rocket using A, B & C motors to see how the altitude achieved changes. We will use devices called inclinometers from two different locations to try and estimate the height reached.
Questions…
- What force keeps the rocket sitting on the launch rod?
- What fuel is used in our model rocket motors?
- Describe one way in which the design of a rocket helps to reduce drag?
- Why are model rockets designed to be as light as possible?
- What might be a good material to make the parachute from? Why have you chosen it?
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