Skumxo I English

– the rocket for playground use.

Here are the instructions needed to build a flight ready scale model of our Nexø I rocket, including how to build a simple launch platform.
Both the rocket and the launcher can be built from parts obtained from the hardware store and/or crafts store. The rocket was developed for the Science in Forum event in Copenhagen.
The parts list below is based on items available in Denmark, and it is our hope that it is possible to obtain the same or equivalent items in your country.

Rocket parts:
Water/heating pipe insulation, polyethylene foam, 1 m length. Outer diameter 44 mm (important dimension!), inner diameter 20 mm (3/4 inch).
EVA foam sheet, 2 mm thick, white.
Double adhesive tape, 12 mm wide. A paper backed type is recommended.
Wine bottle cork, preferably unused (23 mm diameter). A used one (from a sacrificial bottle of wine) will need a layer of duct tape to increase the diameter a bit.

Launcher parts:
Electricians plastic conduit, diameter 20 mm (3/4 inch), 2 m length.
90 degree bend for electricians plastic conduit, 2 pieces.
Large PET water bottle, the kind that can be easily deformed. Not the coke/fanta kind.
Duct tape.

Rocket build:

Watch the short video tutorial for instructions.
The directors cut, extra long version, can be found here.
The rocket foil sticker is available here, and a template for the fins is available here for you to print out.
For a more rustic rocket model, it is possible to make do with this cheapskate rocket template. For additional instructions, have a look at the pictures in the danish version of this article.
If you decide to use the cheapskate rocket template, you should cut and assemble the rocket nose first, then trim the foam tube to 793 mm length, and then cut the slits for the fins.
The video doesn’t show what to do with the cork, so that is explained here: Insert the cork in the bottom end of the rocket, where the fins are. Push the cork approx. 30 cm into the rocket, using the electricians conduit or a wooden rod.
The cork must be a very tight fit.

Launcher build:

Cut a 30 cm length of the plastic conduit, and cut the remaining long piece of conduit in half. Deburr all cut conduit ends.
Use the two 90 degree bends to assemble the three pieces as shown below. The PET bottle is attached to the end of the long piece of conduit. Use duct tape to make an airtight seal.
skumxo-launcher
The rocket is mounted on the short upright conduit piece, and is subsequently launched by stomping (or jumping!) on the bottle.
Recharge the now flattened bottle by blowing hard into the upright conduit piece.
Launch again.
And again.
And again …