Water Rocket Project

by mtairymd

30K3117

Intro: Water Rocket Project

Water rockets are used in school/scouting/4-H presentations to help students understand the principles of aeronautics. This project is geared towards middle school aged students. However, the project has been given to high school students and they enjoy it as well. Everyone is happy to get out of class and play with water.

Five rocket stations should cover a typical class (divide the kids equally). The stations are pretty easy to build and relatively safe since the PVC reducer locks the rocket in the vertical position. Fins and nose cones were not added since this setup needs to be durable to cover multiple classes per year.

Note that the rocket release is not controlled. The rocket launches when the pressure inside the bottle forces the stopper from the nozzle. For this reason, the kids should stand back when applying pressure to the bottle. Depending on the stopper seal, rockets can fly as high as 50 feet.

This project was built for an intro to engineering program called DiscoverE. For more information on the program, see this link: http://www.discovere.org/

STEP 1: Materials and Tools

Materials:

  • Wood - 16” x 16” x .25”
  • Wood - 2.5” x 2.5” x .75”
  • PVC Pipe 3 3/8” diameter
  • PVC Reducer - 5” x 4”
  • Waterproof glue
  • Bicycle pump
  • PVC Clear Vinyl Tubing (3/8” diameter) – 10 feet long
  • Hose clamps
  • Rubber stopper
  • Inflating needle
  • Tape
  • 2 Liter Bottles
  • Water jugs
  • Water

Tools:

  • Saw
  • Ruler
  • Screw driver

STEP 2: Cut Baseplate

Cut sheet of wood 16” x 16”. Optional – cut 3 3/8” diameter hole in center of board.

STEP 3: Add Baseplate Blocks

Add baseplate blocks to the four corners of baseplate.

STEP 4: PVC Pipe

Cut pipe 3 3/8" diameter PVC pipe to 9”. Cut slot as shown

STEP 5: Attach Pipe to Base

Glue pipe to center of board. If hole was placed in board, slide pipe through hole and glue both sides. This will give a stronger setup.

STEP 6: Add Reducing Fitting

Place reducing ring on top of PVC pipe. This completes the rocket launcher setup.

STEP 7: Extend Hose

Extend the length of bicycle pump hose by cutting it in half and adding in the clear tubing. Use hose clamps to seal the ends.

STEP 8: Stopper (cork)

Drill a small hole through the rubber stopper – just enough to fit the needle through the hole (needs to be a tight fit).

Feed the needle through the stopper so the threaded side is on the wide end of the stopper. Clamp the stopper to the pump. If needed, add tape for additional support.

This completes the pump assembly.

STEP 9: Add Water

Add water to bottle – question the kids on how much water should be added.

STEP 10: Place Reducing Fitting on Bottle

STEP 11: Press Stopper Into Bottle

STEP 12: Place Bottle/reducer/stopper Assy Onto Pipe

STEP 13: Ready to Launch

STEP 14: Shoot the Rocket

Move pump away from rocket and start pumping. Rocket will release when the pressure overcomes the friction of the stopper.

See embedded video for actual launch!

7 Comments

mtairymd 10 years ago

Thanks for all the comments. I agree that a trigger, fins, etc. would make it more exciting. However, this particular setup is used for kids as young as 8 years old so limited energy and vertical launching is a good thing from the safety standpoint. We had a trigger version that fell over last year and almost took a teacher's head off...not good publicity. Also, this setup is used for 500+ rambunctious kids per year so durability is very important.

Gamer Guy 10 years ago

A couple cool things you could do to make it even cooler are:

Make it look like a rocket! Trick it out with some fins!

Add something to hold the rocket so you can get max pressure, then release for max height!

Awesome project!

Azzurro 10 years ago

When i was a kid i made this, but a little different. If i may suggest: put 3 wings under the top of the bottle, like on a rocket. (see that guy in the image) Then it will fly like a rocket and not like a piece of plastic thrown up in the air. It can also stand on the wings, so no need for the pipe. I also put a half rubber ball on the bottom of the bottle, so it won't break when landing, and probably flies better.

rickharris 10 years ago

From experience the rockets go further if you arrange a physical release system - the average PET bottle will stand 80+ bar and then it is usually the lid that blows off The bottle body is good for 100+ bar.

A pretty common release is to use a ring of cable ties round the lip of the bottle neck But I used a simpler system with a U shaped wire staple across the bottle neck lip through a ply wood stand and then pulled it out with a string (I don't like getting wet.)

Fins made from another bottle are also worthwhile additions.

Nice introduction to water rockets.

Involved Observer 10 years ago

Very simple and clever design. Thanks for the instructable, this will be a big hit with my Scout troop this summer!