How to Build a PVC Water Bottle Launcher

Building an air-powered soda-bottle rocket can be a fun project to do at home with your kids, or a great science project for a group. The rockets, which are simply soda bottles, can fly 30 feet in the air using nothing more than water and air to propel them, providing hours of safe entertainment. You can use common PVC plumbing parts available at your local home center, hardware store or building center. Even though they're relatively safe, soda-bottle rockets should not be used by children without adult supervision.

Things You'll Need

• 6 feet of 1/2-inch PVC pipe
• Hacksaw
• Drill
• Drill-bit set
• 1 old bicycle inner tube with a valve stem on it
• Scissors
• Bathtub sealer
• PVC pipe cement
• 1-1/2 inch PVC tee (slip fit on to sides and female threads on the tee section)
• 2-1/2 inch PVC glue on caps
• 1-1/2 inch PVC glue on elbow
• 2-1/2 inch PVC glue onto male threaded adapters
• Black electrical tape
• Soda bottles
• Water
• Bicycle pump

Instructions

Building the Launcher

1. Cut the PVC pipe into four pieces. You will need one 3-foot section, two 1-foot sections and one 4-inch section of pipe. You can use a hacksaw or pipecutter to cut the PVC pipe.

2. Drill a hole in the center of one of the pipe caps. The hole needs to be just big enough for the valve stem from the inner tube to fit snugly, but not so tight that it gets damaged when inserting it.

3. Cut the valve stem out of the inner tube using scissors or shears, leaving a small amount of rubber around the base. Insert the valve stem into the hole in the cap and use some bathtub sealer to seal all the way around the valve stem. Set aside to dry according to the manufacturer's specifications.

4. Assemble the two 1-foot sections of PVC pipe into the tee fitting using the slip-in part of the tee and PVC cement. Leave the threaded section of the tee open for now.

5. Glue the two end caps onto this assembled section. It doesn't matter which end each cap goes on, as long as they are both glued securely to this section.

6. Glue the elbow to one end of the 3-foot section of PVC pipe and one threaded male fitting on the other. Glue the 4-inch piece of PVC into the other side of the elbow and add the other male fitting on the other end of this section. Wrap this threaded section with black electrical tape.

7. Thread the male fitting on the 3-foot section of PVC into the tee making sure that the 4-inch section is pointing up at a 90-degree angle. This will be the launcher for your bottles.

Launching the Bottles

1. Fill an empty soda bottle about 1/4 of the way with water. Slip it onto the fitting that is sticking up. The electrical tape will make this a tight fit; you may need to screw it on.

2. Attach a bicycle pump to the valve stem and begin to pump. This will add pressure to the PVC pipes as you pump.

3. Continue pumping until the bottle launches from the launcher. This normally happens at around 30 PSI. Bottles can travel to heights of 30 feet or more.

Tips & Warnings

• Do not stand near or over the bottle while pressure is being applied to the launcher. While the bottle will usually leave the launcher when the pressure reaches around 30 PSI, the exact moment the bottle launches can be unpredictable.

References

• Soda Bottle Rocket