Instructions for Building the Launcher:
The launcher is simple and inexpensive to construct. Most needed
parts are available from hardware stores. In addition you will need
a tire valve from an auto parts store and a rubber bottle stopper
from a school science experiment. The most difficult task is to
drill a 3/8-inch hole in the mending plate. An electric drill is
a common household tool. If you do not have access to a drill or
do not wish to drill the holes in the metal mending plate, find
someone who can do the job for you. Ask a teacher or student in
your school's industrial arts shop or the parent of a student to
· 4 5-inch corner irons with 12 3/4-inch
wood screws to fit
· 1 5-inch mounting plate
· 2 6-inch spikes
· 2 10-inch spikes or metal tent stakes
· 2 5-inch by 1/4-inch carriage bolts with 6 1/4-inch nuts
· 1 3-inch eyebolt with 2 nuts and washers
· 4 3/4-inch diameter washers to fit bolts
· 1 #3 rubber stopper with a single hole
· 1 Snap-in Tubeless Tire valve (small 0.453 inch hole, 2
· Wood board 12 x 18 x 3/4 inches
· 1 2-liter plastic bottle
· Electric drill and bits including a 3/8-inch bit
· Screw driver
· Pliers or open-end wrench to fit nuts
· 12 feet of 1/4-inch cord
Construction of the Launcher
- Prepare the rubber stopper by enlarging the hole with a drill.
Grip the stopper lightly with a vice and gently enlarge the hole
with a 3/8 inch bit and electric drill. The rubber will stretch
during cutting, making the finished hole somewhat less than 3/8
- Remove the stopper from the vice and push the needle valve end
of the tire stem through the stopper from the narrow end to the
- Prepare the mounting plate by drilling a 1-3/8 inch hole through
the center of the plate. (As safety precautions, hold the
plate with a vice during drilling and wear eye protection.)
Using a drill bit slightly larger than the holes, enlarge
the holes at the opposite ends of the plates. The holes must be
large enough to pass the carriage bolts through them.
- Lay the mending plate in the center of the wood base and mark
the centers of the two outside holes that you enlarged. Drill
holes through the wood big enough to pass the carriage bolts through.
- Push and twist the tire stem into the hole you drilled in the
center of the mounting plate. The fat end of the stopper should
rest on the plate.
- Insert the carriage bolts through the wood base from the bottom
up. Place a hex nut over each bolt and tighten the nut so that
the bolt head pulls into the wood.
- Screw a second nut over each bolt and spin it about halfway
down the bolt. Place a washer over each nut and slip the mounting
plate over the two bolts.
- Press the neck of a 2-liter plastic bottle over the stopper.
You will be using the bottle's wide-neck lip for measuring in
the next step.
- Set up two corner irons so that they look like bookends. Insert
a spike through the top hole of each iron. Slide the irons near
the bottleneck so that the spike rests immediately above the wide
neck lip. The spike will hold the bottle in place while you pump
up the rocket. If the bottle is too low, adjust the nuts beneath
the mounting plate on both sides to raise it.
- Set up the other two corner irons as you did in the previous
step. Place them on the opposite side of the bottle. When you
have the irons aligned so that the spikes rest above and hold
the bottle lip, mark the centers of the holes on the wood base.
(For more precise screwing, drill small pilot holes for each
screw and then screw the corner irons tightly to the base.)
- Install an eyebolt to the edge of the opposite holes for the
hold-down spikes. Drill a hole and hold the bolt in place with
washers and nuts on top and bottom.
- Attach the launch "pull cord" to the head end of
each spike. Run the cord through the eyebolt.
- Make final adjustments to the launcher by attaching the pump
to the tire stem and pumping up the bottle. Refer to the launching
instructions for safety notes. If the air seeps out around the
stopper, the stopper is too loose. Use a pair of pliers or a wrench
to raise each side of the mounting plate in turn to press the
stopper with slightly more force to the bottleneck. When satisfied
with the position, thread the remaining hex nuts over the mounting
plate and tighten them to hold the plate in position.
- Drill two holes through the wood base along one side. The holes
should be large enough to accommodate large spikes (metal tent
stakes). When the launch pad is set up on a grassy field, the
stakes will hold the launcher in place as you yank the pull cord
to launch the rocket.
- The launcher is now complete.
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Any comments, concerns, or questions should be addressed
Responsible NASA Official: Jo Ann Charleston