Introduction: A Two-bottle Water Rocket That Flies Up to 400 Feet High

About: I am a student of the Třeboň High School in the Czech Republic. I'm interested in astronautics, astronomy and robotics.

In this instruables I know I will show you how you can easily make a large water rocket with a parachute that can fly higher than 400 feet. Let's go!


three 1.75L pet bottles from coca-cola

duck tape



some wooden boards

cork stopper



Step 1: Splicing Bottles

For a water rocket, the tank is the most important, and for a double-bottle water rocket, it is also the most difficult part. First you have to prepare one screw with a thread diameter of at least 5mm. Then you have to insert this screw into the vice and drill a hole with a diameter of approx. 3 mm in the axis of the screw. Subsequently, it is necessary to make a hole in the bottom of one pet bottle as large as the thread of our screw.Then you need to insert the screw into this hole so that the head is inside the bottle and don't forget to give the bottle and the screw seal! Then all you have to do is drill the same hole in the bottle cap as we drilled in the recess, add a seal, thread the cap on the thread and screw the nut onto the end.

Step 2: Making Fins

Fins are also very important for rocket flight. They have the essential function of stabilizing the rocket.I made four wings out of hard cardboard and connected them with a strip of cardboard. You can stick them to the rocket with duct tape or hot glue gun.

Step 3: Making Parachute

Now comes another important thing: a parachute. I made a parachute from a 60L garbage bag. Instructions for the parachute can be found in this video: from

Mr. Kryzer. I only used 8 instead of 16 strings. Then I cut off the top of the bottle, which is our aerodynamic cover for the parachute. Be sure to put some weight in the cover. then all you have to do is glue the parachute to the top of the rocket and the rocket is ready.

Step 4: Makeing Launch Pad

Once we have the rocket ready, we have to make a launch pad for it.We start by finding a 25 * 25cm wooden board into the corners of which we drill about 2mm holes.Then we find two wooden boards measuring 15 * 10 * 2 cm and drill them on a wooden board. then we take a cork stopper, drill a hole in it and put a valve in it. Then we drill a hole as big as our cork into another wooden board with dimensions of 10 * 7 * 0.5cm and attach the board to the other two. Subsequently, it is necessary to attach 4 L perforated components to the top plate as you can see in the picture and find or create a component that can be inserted into these holes. Then all you have to do is attach a string about 5 m long to this part and the ramp is done: D.

Step 5: 3,2,1 Liftof

When we have the ramp and the rocket ready, we only have one step left: to start it! First you need to find a suitable starting point, for example a meadow. Then you have to transport the rocket with the ramp to this place and nail the ramp to the ground with four nails so that it does not overturn. Then you have to pour about 3 liters of water into the rocket and put the rocket on the cork on the ramp. Then you have to fold the parachute and put it under the aerodynamic cover to check if everything is in order and secure the rocket with ticks. Then connect the pump to the valve and you can start pumping. I recommend pumping a maximum of 100PSI so that the rocket does not explode. After pressurizing, just go aside to grab the string and start counting down 3,2,1 Start! when you want to start, jerk the string properly and the rocket will fly high into the clouds. Then the parachute opens and lands gracefully on the parachute.

If you have any questions, write in the comments and I will be happy to answer. If you liked this project, please vote for it in the Space contest. I will be very happy for all your votes.

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