91301f/3 Water Rocket

Hong Kong Institute of Vocational Education (Tuen Mun) 91301F/3 Water Rocket

Introduction As we work at Toy’s Company, we need to produce a toy rocket for children of 12 years of age and older. This toy rocket should flies considerably higher vertical height and longer flight time than other toy rocket on the market. This water rocket use air pressure and water to power .

Objective 

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Use two 2 liter pop bottles to built a water rocket Built other element of water rocket: nose cone, empennages and parachute Built a launch lug to keep the water rocket vertical to launch and flight Develop a website for illustrating all the concepts and theories

Theory We use the rocket launcher to keep the bottle be a confine area. When we 打氣 into the confine area, it’ll increase the air pressure. If the pressure larger than 承受 of the rocket launcher, it’ll make the rocket launcher 分離 ,then the water will out of bottle, and this is the action force. The rocket has a reaction force moving in opposite direction. This is Newton’s Third Law: “for every action there is an equal and opposite reaction”. The volume of out of water per second and the speed of out of water is determine the rocket’s power force. If two of these are larger, the rocket’s power force must be large. So, when we design the rocket, we should keep the pressure in the bottle be large and the volume of water should be suitable . Also, we use parachute can keep the rocket stay longer at the 空中 . It also can ensure the rocket 平緩降落 . Install the nose cone and empennages can keep the rocket stable to flight, this is the 流體力學原理 .

Material of Water Rocket A Parachute

Empennages The making process of empennage: 1. Cut a trapezoid in material transparent film. (The dimension are shown as the above figure)

The making process of parachute: 1. Prepare a hexagon with material plastic bag. Each side is in 400mm with 120° interior angle 2. Cut a Ø74 hole in the middle of the hexagon 3. Prepare 6 equal length ropes 4. Tie the rope to every edge

Material of Water Rocket

The rocket launcher

Material of Water Rocket The plane has 4 small hole at the edge, the diameter of each edge is 6mm. In the middle of the small hole, the diameter is 8mm. In the middle of the big hole, the diameter is 27mm.

The plastic plane of launch

Material of Water Rocket

Material of Water Rocket This nose cone is made of 卡紙

nose cone

Construction of Water Rocket

The rocket launcher We stick four empennage on the bottle outside. Each empennage with 90 °

Construction of Water Rocket

The launch

Construction of Water Rocket The launch lug

The parachute inside the nose cone

This figure shows our water rocket, launch ??? and launch lug

The problem we face •

How to make the rocket vertical to launch???  We make a launch lug to keep the rocket vertical to launch.

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How to make the rocket stable to flight???  Use empennage and parachute. Stick the empennage at 下端 of bottle. Install the parachute at 上端 of the rocket.

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Try different water volume make the water rocket launch to a higher position

Conclusion In conclude, our water rocket launch was successful. In the producing water rocket process, we had many problem need to solve, and finally, we can success to solve all the problem and produce a water rocket.

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http://www.esnips.com/doc/9143643d-80cf-46b6-ad7c-0bba328f7616/IMG_161

http://www.esnips.com/doc/e946717f-d482-45ff-8849-4c4bd79d1c29/IMG_1612