The trabuco was a weapon used in the later part of the Middle Ages (circa 5th to 15th centuries A.D.) used to demolish fortress walls or to send flying projectiles over them. This instrument of war was able to effectively transform gravitational potential energy into kinetic energy. It is also known as the counterweight blunderbuss.
The trabuco was capable of hurling projectiles weighing 300 pounds up to 875 yards and was fairly accurate according to veja.abril.com.br. The physics behind the trabuco is one of counteracting proportion. Employing a counterweight of different measures would determine the velocity and range of the weapon. The larger the counterweight used, the faster and further would the projectile be hurled. Some historical reports on merriam-webster.com indicate that disease infected bodies were used as projectiles as an early form of biological warfare employed in the Middle Ages.
The exact history of the invention of the trabuco is somewhat sketchy. The invention actually derives from the more simple technology of the sling. An evolution of the concept of the sling employed a small piece of wood to provide a better lever and extend the range of the weapon. This evolution continued thanks to the Chinese, but the first reports of a counterweight blunderbuss do not appear in the Chinese historical records until 1268. It is surmised that it may have been developed in the Jurchen Jin dynasty (1115 – 1234 A.D.) according to help.madmoo.com.
The counterweight blunderbuss, or trabuco, appears in the historical record in Europe during the Byzantine Empire. During an attack on Lisbon in 1147, it was recorded that two trabucos had the capability to launch a projectile every fifteen seconds. Richard the Lionheart employed two trabucos in the attack on Acre in 1191. He named the two trabucos “God’s Own Catapult” and “Bad Neighbor.”
As it turns out, the eventual end of use of the trabuco as a primary weapon in warfare takes us back to China and the invention of gunpowder. The earliest historical record containing the formula for gunpowder is from the Song dynasty (11th century A.D.). The weapon of choice in warfare for attack and siege became the canon.
Search more about Trabuco: https://pt.wiktionary.org/wiki/trabuco