Document 160997

How to build a very simple trebuchet
You will need
Strong cardboard, pencil, a thick elastic band, masking tape,
glue, scissors, plastic teaspoon and rolled up tissue paper.
Thread the elastic band through all three holes, glue and
tape the lever to the base.
How to make
Cut the cardboard into 2 pieces:
15cm x 15cm (the base)
5cm x 15cm (the lever)
Fold the lever in half so you get a folded piece 5cm x 7.5cm.
Pierce holes in the centre of each side of the lever.
T
Tape
the plastic teaspoon
to the upper side of
to
the cardboard with the
b
bowl
of the spoon facing
d
downwards.
Pierce another small hole in the middle of the base.
Cut the elastic band and knot one end. Pull the elastic band
up through the cardboard base and through both holes in
the lever. The knotted end of the elastic band will be under
the base.
P the elastic band tight
Pull
a knot.
and
Glue and tape one side of the folded lever to the base.
Knot the other end of the elastic band tightly. The shorter
the length of elastic band between the knots, the more
tension you create in the folded cardboard lever.
Hold firmly!
Tape the plastic teaspoon to the upper side of the
cardboard with the bowl of the spoon facing downwards
towards the base.
Hold the base firmly and pull the spoon back, put the rolled
up tissue paper in the bowl of the spoon and let go.
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Load the spoon with
rolled up tissue paper and
let go!
How to build a trebuchet
You will need:
Heavy object, ball of clay, small screws and nails, glue gun, eyehooks, wire, string, piece of cloth, steel axle and assorted pieces of wood.
1. M
Make two side frames: we used one
p
piece of wood 20cm long and one 15cm
lo
long - both were 2cm wide by 1cm
tthick. The triangular strengthening
p
piece was plywood glued in place.
D
Drill holes at the top of each vertical
p
piece of wood - the hole should be a
free fit for the axle.
2. Using glue and nails
fasten the two side
frames together using
10cm long pieces of wood.
3. Make the swing arm using a 2cm x 2cm x 25cm piece of wood.
4. Drill holes sstarting
arting
g5
5cm from on
ne end for the axle. Screw an
one
eyehook into one end
nd and the sid
de at the other end.
side
Hammer a n
nail into this end.
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5. Put the swing arm into
p
place using the axle: this
sh
should swing freely!
Putting it all together
How to build a trebuchet
The heavy weight could
be some old D batteries
or lots of coins in a
plastic bag.
T the heavy weight to the end of the
Tie
s
swing
arm.
Hold the swi
swing
ing
g ar
arm down
when loading the trebuchet.
tr
e fi
final
ttwo
o p
arts
The
nal tw
parts!
Tie a loop into one end of the pouch
ove the nail. This
string and loop over
will release when the swing arm lifts,
g the ball!
thus releasing
fro some cloth
The pouch is made from
tied at both ends with string: try
‘pock to keep
and make a little ‘pocket‛
the clay ball in place.
Tie one end of the pouch string
tring
to the eye on the side of the
he
swing arm.
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Time to try it out!
How to build a trebuchet
Warning - missile in flight!
Fasten the base
to a desk
When you have loaded the trebuchet clear the area,
sound the warning and let go!
You will almost certainly need to experiment with
the weight and which hole the axle is in to get the
best results.
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