Trabuco were weapons of the middle ages originally invented in China. They were large monstrous looking things used for battle. These machines were used to lay siege to castles and bring down walls in the middle ages. The first of these machines was not as effective it was not until the Arabs took these machines and added a weight to one side. The Trabuco were the weapons of choice until gunpowder was invented.
The Trabuco is a large machine that is similar to the catapult. Like the slingshot, the Trabuco uses the momentum of turning potential energy into kinetic energy.
Read more on dicio.com.br
The machine stands on two base legsaccording to lista.mercadolivre.com.br. The legs have attached wheels or are carried to the site. The legs on the top are attached to a lever that moves up and down. The lever has a larger arm on one side and shorter arm on the other. The arm on the shorter side has a heavy weight attached to it. The larger arm has a rope or string attached to it that runs the length of the larger arm. The string or rope is then attached to a net or cloth that can carry a large stone or sharp wooden sticks as weapons that are thrown at the enemy. The smaller arm is pulled down and the larger arm does up. The weight of the larger arm moves up which is attached to the string or rope. The shorter arm with weight is released which in turn releases the stones or sharp wood which is on the string or rope according to merriam-webster.com.
The weapon releases the stones or sharp weapons and it is hurled to the castle or wall. The great thing about this type of catapult is the speed at which the rock or sharp sticks are thrown. They were also used to throw fireballs at their enemies. The more mass the shorter arm carries the stronger the speed of the rock or sharp weapons are that launched.
Search more about Trabuco: http://veja.abril.com.br/blog/sobre-palavras/trabuco-da-astucia-ao-chumbo-grosso/