Feb 12, 2018

DIY: Rocket launcher for paper/water rockets

After watching the SpaceX launch with my kids, I was inspired to build a rocket launcher to continue their excitement for the sciences. The rocket launcher can launch paper rockets and water bottle rockets.

The rocket launcher is powered by a bike pump and activated via a flip switch. I modified the design from https://www.youtube.com/watch?v=eNFfK5uo6D0 by integrating the base into the pressure chamber and using a bike tube Schrader valve. The rocket launcher is built from PVC pipe with 1 1/2" main chamber and 3/4" legs and launch tube. The valve is a 24V sprinkler valve powered by 2 9V batteries connected in series and actuated via a flip switch. The system can be pumped up to 140 PSI, and the rockets can be built from card stock and tape.

Build complete

Tools used:

Wire stripper
Wire crimper
PVC pipe cutter
Drill bits


PVC primer
PVC glue
Flip Switch
2 9V batteries
2 9V battery connectors
Teflon tape
Electrical spade connectors (use whichever wire connectors you're comfortable with)
1 coffee can to mount the switch
1 used bike tube for the Schrader valve
3 | 3/4" pipe end caps (the photo shows 2 3/4 inner diameter end caps which was wrong)
5' | 3/4" PVC pipe
3 | 3/4" x 1 1/2" T PVC adapter
1 1/2" T PVC3/4" T adapter
2 | 1" x 3/4" threaded PVC pipe adapter (this was used for a 1" threaded sprinkler valve)
24V 1" sprinkler valve
3/4" washer

Cut out the bike tubing with scissors around the Schrader valve (or purchase a Schrader valve if you don't have a used tube). Ensure you leave enough rubber material to make a good seal within the 3/4" end cap. Insert the end cap into a vice. Drill out the 3/4" end cap with a drill bit slightly larger than the Schrader valve.

Insert the Schrader valve, then insert the washer. For all PVC connections, prime (purple can) each mating surface. Then add glue (clear can) to each mating surface and immediately press fit. Cut a 6" length of 3/4" PVC pipe using the PVC pipe cutter, and then glue into the 3/4" x 1 1/2" PVC adapter. Glue the 3/4" x 1 1/2" PVC adapter to the 1 1/2" T PVC.

Glue the end cap onto the 3/4" pipe.

The inserted washer keeps the valve in place when inserting the bike pump,

Use PVC pipe cutter to cut the sections to length and glue. Next, we'll glue the remaining 2 of the 3/4" x 1 1/2" PVC adapter to the 1 1/2" T fitting. (The one going vertical and the one extending to the rear of the base) To make the base, cut 2 pieces of 4" section of 3/4" pipe and glue to the 3/4" x 1 1/2" PVC adapter going vertical and to the rear. Connect and glue the 3/4" T adapter and glue 3/4" pipe to each side. Glue the 3/4" caps at the end of the 3/4" T. Add teflon tape to the threads of the 1" x 3/4" threaded PVC pipe adapter. This is the adapter that connects the 3/4" PVC to the 1" Sprinkler Valve. This will keep the system sealed.

Connect the batteries in series. Insert the connector leads to the top of the batteries and press down on the connector. A momentary switch would function better since you wouldn't have to turn the system on and off every time with the flip switch--the flip switch feels legit though.

Wire connectors crimped to the ends of the wire using a wire electrical wire crimp tool.

The battery leads are pressed underneath the connectors, so no need for soldering. All electrical connections are now connected via the wiring diagram. Spade and corresponding female connectors were used.

Paper rocket built from rolled up card stock, tape, and a McDonalds french fry holder. Roll up paper on some scrap 3/4" PVC. Tape the entire length of the rocket. Seal the top of the paper with tape. The air will launch the rocket, so the top of the rocket needs to be sealed. Tape a nose cone, and tape the fins. Insert paper rocket on top of the 3/4" launch tube.

10...9...8...7...6...5...4...3...2...1...Blast off!