Water Bottle Rocket Launcher

The following custom design for a 2-liter water bottle rocket launcher depicts the launcher mechanism only. The launcher should be fastened to a board which is anchored to the ground. Appropriate safety measures must be taken before and during any launch from this mechanism.

Construction Details

Materials needed:

Aluminium sheet: 1.5 mm to 2.0 mm thick, about 7 cm wide x 36 cm to 42 cm long
Steel rod: 3 mm to 5 mm in diameter and 35 cm to 40 cm long (can be Zn coated)
Automobile tire valve rubber coated for pumping in air

Hints: Do not over bend the Al; make sure that the tire valve holds well by making the hole small enough to snap it into place; ensure that the U-shaped rod holds the bottle tightly but can be pulled back easily.

Drill the hole for the tire valve before bending the Al sheet. The valve must be a snug fit.
Insert the tire valve.
Gently bend the Al between the long side 1 and side 2. Do not make the bend too sharp, or else the Al will break. Check that the bottle fits on the valve and is straight.
Make the other bends. Again check the fit of the bottle. Side 3 should just touch the bottle.
Now bend the rod at the middle around a form such as a 2.5 cm diameter pipe until the two long sides are parallel.
Drill the two holes about the diameter of the rod in side 1 that are 2.5 cm separated, not 2.5 cm center to center. Before drilling, double check the hole locations against the fit of the bottle so that the rod will pass the bottle lip very closely when the bottle is pushed down on the tire valve.
Insert the U-shaped rod through the holes and check that the bottle is held securely onto the valve.
Mark the appropriate hole locations, about 5 cm apart, on side 3. Remove the rod.
Drill the two holes in side 3 for the rod ends.
Bend the rod to fit properly - this bending may need several adjustments. When pushed inward, the rod separated by 2.5 cm should catch the lip of the bottle, and when pulled outward the rod should no longer catch the lip to allow the bottle to escape unencumbered. You will need to determine a good fit by trial and error.
Carefully, with force, insert the U-shaped rod completely into the launcher for the final time. Check the bottle's fit. Make adjustments if necessary by bending the rod a little or, possibly, the Al.
Bend the tip of one end a little to prevent further removal of the U-shaped rod.
Launch a rocket under the appropriate safety conditions.

Diagram

This activity has been copied, with permission, from the University of California at Irvine server to ours, to allow faster access from our Web site. We encourage you to explore the original site.