Introduction: Water Rocket Launcher

Difficulty: Easy

Time: +/- 3 hours

The project is a water rocket launcher with a simple manual trigger.

It allows to manage the pressure and send the rocket on time. The techniques used as well as our inspiration comes from the excellent website content:

Thanks to PapyJo for all these explanations and experiences sharing.

We did this project for kids during their holidays and they loved it!

Step 1: Tools and Material


  • Hand drill
  • Screw gun
  • Hole saw Ø26mm
  • Wood bit Ø8mm


  • 1x connector Gardena© male (Type 1750) or similar (The diameter of the connector must be able to host the bottle cap.)

  • 1x connector Gardena© female or similar.
  • 2x Soft PVC tubes | Internal diameter 8mm | Length: 2x 100mm.
  • 5x Colson.
  • 2x Cord | Length: 4m.
  • 2x Aluminium tube| External diameter 8mm | Length: 1x 300mm – 1x 250mm.
  • 1x Epoxy glue.
  • 4x Wooden plank | Dimensions: as you want. For this one: 2x 300mm x 300mm | 2x 300mm x 80mm.
  • 8x Wood screws | Length: 40mm.
  • 2x Small metal hook or buckle.
  • 1x Tube valves.
  • 1x Bicycle pump

Step 2: Top Plate

On one of 300mm x 300mm wooden plank, drill (using the hole saw 26mm) a hole to accommodate the Gardena female connector and drill two holes (8mm) left and right of the fitting hole (about 10mm). These holes will move the cords.

Step 3: Bottom Plate

Overlaying the two plates (300mm x 300mm), the pierced plate above.

Have a pen through the holes to mark the bottom plate. Where marked, screw the metal buckles.

Step 4: Front Plate

On one board 300mm x 80mm drill two 8mm holes in the center

Step 5: Assembling

Assemble the plates.

Step 6: Prepare the Connector

Insert the 300 mm aluminum tube into the female connector.

40mm will highlight the bottom. Glue them together.

Step 7: Assembling Connector

Insert the connector into the top plate. The connector can be screwed into the wood. Glue if necessary.

It is important to put enough glue to ensure a good seal.

Insert the aluminum tube 250 mm by the side plate.

Connect the two aluminum tubes with PVC tube.

Tighten the straps and glue.

Step 8: Prepare the Cap

1. Meanwhile drying, take Gardena male connector and remove the joint.
Sand briefly outside the bottle cap and into the connector.

2. Glue within the connector and cap.
Be generous! It is important that it is properly sealed. Put it together.

Step 9: Assembling the Valve and Tube

1. While this dry, assemble the second PVC tube with valve.
Glue and tighten with a colson.

2. Assemble the PVC tube and the valve.
Tighten with a colson and glue it.

Step 10: Fixing the Cords

1. On the female connector, switch colson. Hook the two cords and tighten the colson.

2. Glue the knots and the colson. The knots are now locked.

Step 11: Passing the Cords

1. Pass the cords through the holes in the buckles and make out through the hole in the front plate.

2. After the highlights, tie them. Secure the knot with glue. Cut one of the string.

Step 12: Finish the Cap

Take the cap and drill an 8mm hole in its center.

The Launcher is done!

You can already propel bottles. This will be testing our best enemy "Leaks"!. Leaks are more easily detectable with bottles filled with water.

To create some rockets with PET bottle you can go on the website: There are a lot of thecnics and ideas.


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