Ballista Project
2
120mm
Axle hole
3
Nails
1
200mm
1)
You will need to make two of these structures, exactly the same dimensions – this is so they
will both fit together.
2)
First smooth the wood down using sand paper and files.
3)
Drill a hole in piece 2 approx 50mm from the base – this is for the dowel rod
4)
Attach piece 1 to piece 2 using one nail. Then after cutting the sides to a 45 degree angle
attach piece 3 to piece 1 – then attach the top to the rear of piece 2.
Ballista Project
1)
Using the remaining 4 pieces of wood, attach them as shown to the other structure. Your
ballista should resemble the image above.
2)
Attach the wood using glue, nails, and screws if need be.
Ballista Project
Ping pong ball housing
Hook
Drilled hole for
dowel rod
1)
Place the metal hook about 60mm from the end of the wooden rod – this will house the elastic
on your ballista
2)
Drill a hole for the dowel rod to go through about 10mm from the bottom of the wooden rod.
3)
Come up with a housing for the ping pong ball to go above the hook. This can be made out of
cardboard or wood.
Ballista Project
1)
Slide the dowel rod through piece of wood 2.
2)
Slide the Ballista arm onto the dowel rod so that it sits in the middle
3)
Slide the dowel rod through the opposite hole
4)
The arm should be moving freely, with NO obstructions. If this is not the case then you will need
to take a rounded file and file the hole until it becomes slightly bigger.
5)
If the arm does not move freely, there will be no power in your ballista
Ballista Project
Hook needs to be placed in
the centre of the front block
Put the other hook on the front of the catapult. The arrow shows where to put it. Then run a rubber
band from that hook to the hook on the catapult arm. If you don't have a rubber band that is long
enough you can tie multiple rubber bands together . Experiment with the length so you get some
good spring action
Ballista Project
You will need to decorate your ballista in your teams colours. You will each
have an attempt at firing it into the target – but ONLY 2 attempts each
Ballista Project