Ballista

This page is about an ancient military weapon. For the death metal band, please see Bolt Thrower (band).

Image:Ballista.gif The ballista (Latin, from Greek ballistēs, from ballein "to throw", plural ballistae) is a powerful weapon resembling a giant crossbow, to eject heavy darts singly or in groups. It is also sometimes referred to as a bolt thrower.

The first ballistae were deployed in Ancient Greece, and were mainly large crossbows fastened on a mount. The first known appearance was in Syracuse, in Sicily, around 400 BC. Roman ballistae differed for the use of torsion power, derived from two thick skeins of twisted cords acting on two separate arms. These usually fired large stones rather than bolts.

Ballistae in the Middle Ages launched bolts, and were thought to have inspired the European crossbow, though 5th century Chinese crossbows may have also been a factor in the development of those weapons and bolt-throwing ballistae.

A ballista's arms are wood, each supported by being spun into the middle of a large rope. The ropes (one per arm) are the springs of the ballista, and made of animal sinew. When the bow-arms are pulled back, they twist the ropes. Winches pull the bowstring back.

Image:Ballista bolt heads.JPG The ballista was a very accurate weapon, but it had to compromise its accuracy for range. The lightweight bolts could not gain the high momentum of the stones thrown by onagers, trebuchets, or catapults — these could be as heavy as 200-300 pounds (90-135 kg).

The precise design of ballistae was a triumph of ancient engineering and mathematics. The ancient ballistas were the most sophisticated catapults ever made. The surviving manuals provide exact measurements and calculations for building ballistae of any size.

The catapult was a variation of the ballista. Image:Ballista.JPG

According to some sources the Roman armed forces at one time in it's history also fielded repeating ballistas, also known as a polybolos. Reconstruction and trials of such a weapon carried out in a BBC documentary showed that they "were able to shoot eleven bolts a minute, which is almost four times the rate at which an ordinary ballista can be operated" [1].de:Balliste es:Ballista he:בליסטרה nl:Ballista no:Ballista pl:Balista pt:Balista ru:Баллиста sl:Balista