Engines of Destruction

Engines of Destruction

There have been countless siege engines over the ages - Mangonels and Onagers, Scorpions and Ballistae, Battering Rams and Siege Towers.

They range from the simplest Battering Ram, a large tree trunk used to knock down gates, Perfectly balanced Trebuchet, capable of hurling huge rocks with great accuracy

Some of them were simply used to knock down walls or gates, so that an attacking force could enter a besieged city.
Some of these weapons have also been used to fire jars of burning liquid, or carcasses of dead beasts, to kill of the enemy.

To prevent an endless list of names, this article will discuss 3 main categories of siege engines, giving the operating principles behind them, and a few examples for each type.

The Battering Ram

The earliest siege engine in existence was the Battering Ram.
The simplest battering ram is simply a big log, carried by the hands of a large number of people.
It was propelled with force at an obstacle, most often gates, to know them down.

However, there is a limit to how big and heavy such a ram could be, and more complex designs involve a much bigger log slung by ropes from a wooden frame. It would be rolled to the gates, and the log would be drawn back and released.
This design has an additional advantage:
The frame could support a roof over the people using the ram, to protect them from the defender's fire.

Another design used wheels on the log itself, or rollers beneath it. This allows for greater speed, and thus greater force, to be used.

The Torsion Engine

Much more complex than the Battering Ram, the torsion engine uses springs to launch arrows, rocks, or anything else.

In the pictured Mangonel, a rock is placed in the sling at the end of a long arm. The arm is connected, by a heavy twisted rope, to an axle.
When the arm is drawn back, the rope tightens and stretches, and when the arm is released the rope snaps back, pulling the arm up and launching the payload.
One should note that the power comes from the twisted rope, and not from the bending of the arm.

Another common torsion engine is the Ballista. Similar to a very large crossbow, the ballista is composed of a grooved central stock, on which the projectile was placed, and two bow like arms on either side. Like the Mangonel, the ballista's arms did not bend. the force comes from ropes twisted around axles, which tightened when a rope connecting the arms was pulled. upon release, the ropes snap back, taking the arms with them, and the connecting rope launches the projectile.

The Trebuchet

More accurate than the torsion engines, the Trebuchet uses a simple lever to launch the projectile.

The pictured counterweight trebuchet uses a crate full of rocks attached to a long beam.
At the other end of the beam there is a sling, which holds the projectile. The beam is pulled down, which causes the crate to rise. When released, the crate falls, causing the beam to rise and launch the projectile.
By using a hook attached to the sling and set to release and open the sling at a certain height, the trebuchet could achieve greater accuracy than the mangonel.

The traction trebuchet is very similar to the counterweight version, but the power is supplied by a team of men or beasts pulling on ropes attached to the beam.