Team+4

Our team name:

Rocket Toast.
Team members: Chase Turner, Jareth Desadier, Sydney Black

WPHS Team: Gabi Mucciolo, Gabrielle Tinnirello, Tess D'Arcy

**TEAM 4 ROCKET INFORMATION:**

The **center of gravity** is a geometric property of any object. The center of gravity is the average location of the weightof a object. We can completely describe the motion of any object through space in terms of the **translation** of the center of gravity of the object from one place to another, and the **rotation** of the object about its center of gravity if it is free to rotate. If the object is confined to rotate about some other point, like a hinge, we can still describe its motion. In flight, both airplanes and rockets rotate about their centers of gravity. A kite, on the other hand, rotates about the brindle point. But the trim of a kite still depends on the location of the center of gravity relative to the bridle point, because for every object the weight always acts through the center of gravity.

Pressure:
The pressure we may need to lift of the ground is between 45-55 PSI. We may also need at least two quarts of water. With the aerodynamics we need the fins exactly equal and a paper towel cone to hold the parachute with also a tennis ball with the parachute string glued to it.


 * Rocket Stability**:

During the flight of a model rocket small gusts of wind or thrust instabilities can cause the rocket to "wobble", or change its attitude in flight. Like any object in flight, a model rocket rotates about its center of gravity **cg**, shown as a yellow dot on the figure. The rotation causes the axis of the rocket to be inclined at some angle **a** to the flight path. Whenever the rocket is inclined to the flight path, a lift force is generated by the rocket body and fins, while the aerodynamic draft remains fairly constant for small inclinations. Lift and drag both act through the center of pressure **cp** of the rocket, which is shown as the black and yellow dot in the figure. On this slide we show three cases for which the flight direction is exactly vertical. In the center of the figure, the rocket is undisturbed and the axis is aligned with the flight direction. The drag of the rocket is along the axis and there is no lift generated. On the left of the figure, a power rocket has had the nose of the rocket perturbed to the right. On the right of the figure, a coasting rocket has had the nose of the rocket perturbed to the left. We denote the angle in both cases by the symbol **a**. Considering the powered rocket case, we see that a lift force is generated and directed towards the right or downwind side of the rocket. On the coasting rocket case, the lift is directed towards the left, also the downwind side of the rocket. For the powered case, both the lift and the drag produce counter-clockwise toques, or twists, about the center of gravity; the tail of the rocket will swing to the right under the action of both forces and the nose will move to left. For the coasting case, both lift and drag produce clockwise torques about the center of gravity; the tail of the rocket will swing to the left under the action of both forces and the nose will move to the right. In both cases, the **lift and the drag forces move the nose back towards the flight direction**. Engineers call this a **restoring force** because the forces "restore" the vehicle to its initial condition and the rocket is determined to be **stable**.

Like an airplane, a model rocket is subjected to the forces of weight, thrust and aerodynamics during its flight. The fins can be made of either plastic or balsa wood and are used to provide stability during flight. Model rockets use small, pre-packaged, solid fuel engines The engine is used only once, and then is replaced with a new engine for the next flight. Engines come in a variety of sizes and can be purchased at hobby stores and at some toy stores. The thrust of the engine is transmitted to the body of the rocket through the engine mount. This part is fixed to the rocket and can be made of heavy cardboard or wood. There is a hole through the engine mount to allow the ejection charge of the engine to pressurize the body tube at the end of the coasting phase and eject the nose cone and the recovery system. Recovery wadding is inserted between the engine mount and the recovery system to prevent the hot gas of the ejection charge from damaging the recovery system. The recovery wadding is sold with the engine. The recovery system consists of a parachute (or a streamer) and some lines to connect the parachute to the nose cone. Parachutes and streamers are made of thin sheets of plastic. The nose cone can be made of balsa wood, or plastic, and may be either solid or hollow. The nose cone is inserted into the body tube before flight. An elastic shock cord is connected to both the body tube and the nose cone and is used to keep all the parts of the rocket together during recovery. The launch lugs are small tubes (straws) which are attached to the body tube. The launch rail is inserted through these tubes to provide stability to the rocket during launch.