The Mangonel

   

The word mangonel is derived from the greco-latin word manganon, meaning "engine of war". It does not have very good accuracy, but hurls projectiles with great speed and power, with the intention of destroying castle walls.

Typical mangonels are powered by a torsion-type string, which is twisted when the catapult arm is pulled back. A handle can be used to tighten or loosen the spring. When the catapult is fired, the spring pulls the catapult arm back to its original position, launching the projectile.

The twisted rope is usually called a torsion bundle. It consists of several lengths of rope with the arm inserted in between them. The rope is then twisted manually on both sides of the arm using levers. When released, the torsion bundle turns the arm at high speed, launching the projectile. The figure below illustrates how a torsion bundle is twisted.   

Parts of the information from:   http://www.real-world-physics-problems.com/catapult-physics.html

The mangonel was mainly used to fire large rocks and other potentially destructive projectiles at castle walls with the aim of destroying or breaching them. The advantage of the mangonel was that it was very practical on the battlefield as well as in the siege or assault of a castle. Mangonels hurled rocks, burning objects, and anything else available to the attacking or defending forces. Because the mangonel hurls objects a low trajectories, these types of projectiles could inflict considerable damage to a variety of targets.

   The two major disadvantages of a mangonel are the inconsistent accuracy, which I mentioned above, and the degrading materials. Since first disadvantage is already thoroughly explained above, I will explain the second disadvantage.
   The mangonel uses tension, which uses ropes. Ropes can lose their elasticity, and both wood and ropes can wear down in natural states. Because of this, battle commanders had to monitor their catapults in case they need replacements. The two disadvantages combined together lowered the accuracy of the mangonel. 






Image source: http://www.real-world-physics-problems.com/catapult-physics.html