Perrier catapult

A type of sling catapult called a Perrier.
Basically a large static version of the Fustibalus (staff sling) it has no counterweight, but relies on the Crew  to pull both down and back to launch the Missile, which makes it a traction operated weapon.
Perriers range from a small, one-person devices to ones pulled by many soldiers or even a team of horses. At any size the traction-powered Perrier was a quite effective weapon because it could be  reloaded and fired relatively quickly.
The only Definition I can find for the word Perrier is this one;
Per´ri`er

n.

1.

(Mil.) A short mortar used formerly for throwing stone shot.

Webster's Revised Unabridged Dictionary, published 1913 by C. & G. Merriam Co

The Perrier is made from  balsawood, a cocktail stick and two pins,
The two Crewmen come from the Zvezda Medieval Heavy Bombard set.
Even though the device looks big, I reckon two would be enough if the arm was balanced correctly it would, even loaded, only need a small amount of force to get it moving.
I´ve left it looking a bit rough and ready, not cutting off the planks flush with the main Support Frame.

The sling is made from a bit of paper, the hook holding the release rope  made by softening the tip of the Cocktailstick in warm water, bending it adding a strip of paper and filling the gaps with PVA.

A couple of contemporary pics of Perrier´s

 Here´s a short Video of a  Perrier being demonstrated at the Tower of London.

 

They are powering it with 4 People, two..one at each side and the other two right under the arm!! This means they have to duck down to avoid being hit with the pulling end of the arm!!

Better to do it like this lot.