Siege Weapons

The challenge was to make a scale model medieval siege engine capable of throwing a marshmallow.

I made two … one was the typical Counterpoise Trebuchet, a long swing arm attached to a counterweight and a sling.

The projectile is placed in the sling and then the arm is lowered and attached to the trigger.

When the trigger is released, the counterweight swings the arm of the trebuchet and the sling is also swing up. When the loop on the sling slips from the pin at the end of the swing arm, the projectile is release.

The counterpoise was fun to make and would throw the projectile (marshmallow, but pictured here with a hazelnut about 8 meters. This siege engine is about 30cm along the base and about 15cm wide.
The other siege engine that I built was an onager or your more traditional looking catapult

The onager is a torsion siege engine, that means that the motive power of the engine is a twisted rope (in this case a 8mm braided nylon cord) that is twisted from both sides of the beam (a bamboo salad spoon).

The torsion sets the beam forward against a padded section of the catapult frame (made from thick felt and more braid).

When the beam is drawn back, the pressure is put on the beam to return it to the rest (forward) position.

I made a simple trigger from three eye screws and a modified nail.
The onager would cast the marshmallow about 6 meters and also has the same (30cm x 15cm) footprint as the trebuchet.