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.
- 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
- 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
- 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
- Launch a rocket under the appropriate safety conditions.
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.
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