Using your Trebuchet

This model trebuchet is designed to throw soft objects.
(rubber balls or bean bags are the best projectiles)

Hard projectiles are dangerous, do not use this model to throw stones or other hard objects.

Always use a string connected to the trigger pin.
This allows you to stand away from the trebuchet when the arm is swinging.
Mark the end of the throwing arm with bright paint or tape.

Filling the counter-weight.

Material for the counter-weight ballast includes pennies, metal washers or tiny sand bags.


Arming the trebuchet.

Secure the arm down with the arm tie-down string.



Place the projectile (rubber ball) in the sling's pouch.
and connect sling to trigger mechanism


Disconnect the tie-down string and hang it on the side of the trebuchet.

Make sure everyone is standing away from the trebuchet and to one side.
(The trigger mechanism now holds the sling and arm in position)

Note red tape on tip of throwing arm, this end moves fast.


Never stand directly in front of or behind the trebuchet.
(sometimes the projectile can be thrown out the back)

Count down from 5 to ensure everyone is watching.
5 - 4 - 3 - 2 - 1 - 0

On "0" pull the trigger string.

The series of images below are frame captures from a video.
Look carefully at images 7 and 8, the red ball is visible as a blur leaving the pouch.

The trebuchet makes an excellent science fair project. Investigations could look at the  effect of different sizes of counter-weight, length of arm,
length of sling, angle of release slot and aerodynamics of projectiles (always use safe projectiles).