Stomp Rocket in the Metric System

Last year, I and other fellow makers of the non-profit association Lille Makers enrolled in a contest. We had choice between making a workbench, an hydroponic system or an outdoor game. We choose to design an outdoor game. In short, our challenge was to design an outdoor game for kids from age 7 to 12, a kit that can be assembled with no tools, a cost less than 150€, with only materials you can find in a harware store or reclaimed materials.

After a number of trials and prototypes, with safety of use and ease of use in mind, we ended with a stomp rocket design and tutorial. There are a lot of tutorials about stomp rockets, but I was maily inspired by this one Makercamp stomp rocket

The idea of stomp rocket comes to me because it seems to be a lesser known rocket system in France, or in the French speaking world. Maybe because "stomp" is not easily translated in French, or maybe because designs available are in imperial mesures and not in metric ones. Or even it is because we can't find in our stores end caps or four pipes connectors you use for stomp rockets I've previously seen (See Mikesaurus Rockets Class for exemple).

Another things great with this stomp rocket is that it is easy to make, even if parents are not experienced builders, it is extra cheap (under 10 euros), and extra fun for kids.

At the end we won the contest ;) and you can read a full story on Makery (but in French ;) La fusee bondissante de Lille Makers. Also Makery found a perfect word to translate stomp rocket in french with "Fusée bondissante" which means leaping rocket.

You can have a look at this video to see this stomp rocket working :

Needed materials and tools :

• A water bottle (In France, the inside diameter of the bottle neck is 25mm)
• A PVC pipe, diameter of 25mm and 2 meter long. You can buy it in hardware stores, to secure electric wires in moisted environnement. I think it is the same as 3/4 in. pipe in the imperial system.
• A PVC elbow (25mm diameter too)
• Some duct tape
• A rubber band
• Paper sheet, cutting tools and tape
• A PVC pipe cutter or a saw
• Optionnal : hot glue gun and sticks

Please note that 25mm PVC pipes and water bottles we found in France fits perfectly, without any adaptator.
It makes things easier to make.
I don't have information about bottle necks and PVC pipes you can found in another countries (europeans/non-europeans =, metric/non-metric).
The best thing to do is to take a bottle and test the bottle neck against PVC pipes in the hardware shop, that's what I've done to test the fitting.

You can use a PVC cutting tool or a saw. You can even use the tools after the pay line at the hardware shop.

Cut a 1 meter long PVC pipe to connect the bottle to the elbow.

Cut two 30cm PVC pipes, one for the rocket (the "firing tube" on the launcher), one another to help making rockets.

The remaining lenght of PVC pipe will be used to make a cross.

Slide the PVC pipe into the bottle neck of the water bottle.
You can secure with duct tape, but you can perfectly do without as it is naturally tight (at least in France).

Take the remaining lenght of PVC pipe and make a cross with the "bottle pipe".

Use rubber band to hold it.

Rubber band is easy and convenient, but sometimes sloppy and you'll have to correct the launcher position between launches from time to time.

For a workshop with several children and several launchers, my advice is to secure the cross with hot glue. You can break it and store PVC pipes easily at the end of the day.

When you don't have acces to four pipes connector, I think it is the easiest system to make for keeping the firing tube vertical.

Connect the elbow to the "bottle tube" or "air tube".

If it is too loose, you can secure the connection with duct-tape or use standard tape to add some layers at the pipe extremity, adding some grip between the pipe and the elbow.

As for the air tube, connect a 30cm tube to the PVC elbow.

As previously, if it is too loose, you can secure the connection with duct-tape or use standard tape to add some layers at the pipe extremity, adding some grip between the pipe and the elbow.

To make a rocket, you'll need the set aside PVC pipe, a sheet of paper A4 at least (21 cm by 29,7cm) and tape (regular and duct-tape).

Use a PVC pipe to make the rocket body with a sheet of paper.

Make it in the long dimension (29,7cm with a A4 sheet for example). I believe it is better for long distance rockets.

Don't roll it too tight. Just a bit loose is best to avoid friction.

Secure the roll with a piece of tape, then tape all the edge of the body length.

Slide the rocket body a little bit out of the pipe, and close the nose keeping the body of the rocket on the pipe.

Fold the head with your thumb, shove the paper inside. You will get a flat head you will seal with pieace of duct tape.

Not the best for the aerodynamic, but great for safety and ease of fabrication.

Still keep the PVC pipe inside the rocket's body.

Cut a sheet of paper in 8 equal parts :
cut the page in half, cut the 2 parts in halves, cut the 4 parts in halves.

Take a eigth of a A4 sheet.
Bend it in half.
Bend two pads, about 1 centimeter large, they will be used to fix fins to the rocket's body.
Bend the corner of the fin to the begin of the pad.
Fix it with tape, to keep the shape.
You have one fin !

Make at least two more fins.

Use tape on pads to fix fins (at least 3) to the rocket's body.
Now you have a rocket to use !

The rocket is reusable, but you can add some tape inside to prevent the rocket to be crimpled in the inside after multiple launches.

Find an open area and try some rockets.

But be warned that you'll become the center of attraction for kids if you go in a public parc ;)

After a launch you can manipulate the bottle with hands to reinflate it.

Pay attention that kids find out quickly that they can reinflate the bottle blowing in the firing tube. Don't let them : saliva will damage paper and they can spread diseases when many kids are playing.
Bottles will last several launches, plastic is very strong. Have a few replacement bottles just in case one break, but a bottle can be used dozens of times.

I hope this instructable will be usefull.

As I don't have a knowledge of bottle necks and PVC pipes sizes and their fitting all aroud the globe, just let me know your country in the comments if you can do the same simple stomp rocket :)