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Sunday, December 9, 2007

CataPault

CATAPULT

For the handheld Y-shaped weapon, see slingshot.

A catapult is any siege engine which uses an arm to hurl a projectile a great distance, though the term is generally understood to mean medieval siege weapons. The name is derived from the Greek κατά (against) and βαλλεν (to hurl (a missile)). (An alternate derivation is from the Greek "katapeltes" meaning "shield piercer," kata (pierce) and pelta (small shield)). Originally, "catapult" referred to a dart-thrower, while "ballista" referred to a stone-thrower, but the two terms swapped meaning sometime in the fourth century AD.

Catapults were usually assembled at the site of a siege. An army would carry a few necessary pieces with them because wood was easily available. Although usually incorrectly depicted with a spoon on the end of the arm (as in the picture to the right) catapults were most often equipped with a sling to hold the projectile.

Types

Catapults may be classified according to the physical concept used to store energy when winched and release the energy when fired required to propel the projectile

Catapult

The earliest documented occurrence of catapults in China was the levered catapult and an eight foot high siege crossbow from the Mozi (Mo Jing), a Mohist text written at about the 4th - 3rd century B.C by followers of Mozi who founded the Mohism school of thought during the late Spring and Autumn Period which is about 6th century BC and 5th century BC and the early Warring States period. Much of what we now know of the siege technology of the time came to us from Books 14 and 15 (Chapters 52 to 71) on Siege Warfare from the Mo Jing. Recorded and preserved on bamboo strips, much of the text is now unfortunately extremely corrupted. However, despite the heavy fragmentation, Mohist diligence and attention to details which set Mo Jing apart from other works, ensured that highly descriptive details of the workings of mechanical devices like Cloud Ladders, Rotating Arcuballistas and Levered Catapults, records of siege techniques and usage of siege weaponry can still be found.[1]

The first European catapult distinct from hand-held launchers (bows, javelins, slings, etc.) was the Greek Gastraphetes, a crossbow so large it was braced against the abdomen rather than being held in the hand, hence the nickname belly-bow. The next step from this was a larger form a crossbow mounted on a stand, including early versions of the oxybeles (Greek for bolt shooter) and the ballista (the Roman version of the oxybeles). The arbalette à tour was a medieval version of the stand-mounted crossbow. These catapults are tensional, in that the energy is stored as tension and compression of the bow. Although similar to a crossbow, a sling on the end of the rope meant these weapons could be used for firing all sorts of projectiles, from rocks to pots of Greek fire.

Subsequently, torsional catapults were developed; those with two torsion powered arms, the later versions of the ballista and oxybeles, and those with one torsion powered arm, the onager, known in medieval times as the mangonel. The bottom end of the throwing arm of the onager and the inner ends of both ballista arms are inserted into rope or fibers that are twisted, providing a torsional store of energy. Torsional ballistas were operationally equivalent to their tensional cousins, except the torsional energy store gave greater power. Onagers have an arm with a bucket, cup, or most often a sling to hold the projectile at one end.

Finally, the last type of catapult is a trebuchet, which used gravity or traction rather than tension or torsion to propel the throwing arm. A falling counterweight, or the effort of the one or more operators, pull down the bottom end of the arm and the projectile is thrown from a sling attached to a rope hanging from the top end of the arm, essentially like a sling attached to a giant see-saw. The counterweight is much heavier than the projectile. More modern trebuchets often replace the counterweight with industrial springs to create tension. (Video).

History

French troops using a catapult to throw hand grenades during World War I.

Improvised catapult made out of leaf spring during the Warsaw Uprising for launching of Molotov cocktails.

In Europe, the first catapults appeared in Greek times around 400 BC-300 BC [citations needed]. According to Greek engineer and inventor Hero of Alexandria, the first types derived from by the earlier gastraphetes ("Belly-bow"), consisting in composite bow mounted transversely on a stock, much like the crossbow. A larger version of this was called an oxybeles and is the precurser to the ballista. Biton attributes the creation of the first crewed catapult to one Zopyrus from Taranto, in southern Italy.

Early adopters of the catapult design were Dionysius of Syracuse (who called it katapeltikon) and Onomarchus of Phocis. Katapaltai are mentioned in the Siegecraft (Poliorkētika) treatise of Aeneas Tacticus, from around 350 BC. It is probable that standard torsion-powered catapults entered in common use in Greek world and Macedon only around 330 BC. Alexander the Great introduced the idea of using them to provide cover on the battlefield in addition to using them during sieges. Projectiles included both arrows and (later) stones.

Romans started to use catapults probably as arms for their wars against Syracuse, Macedon, Sparta and Aetolia (3rd-2nd century BC). Standard use of artillery (ballista and onager) is attested only from the time of Julius Caesar, however.

In the Medieval times, when the trebuchet was introduced a relatively short time before the advent of gunpowder, the catapult became basically obsolete. Cannons soon replaced catapults as the standard siege weapon in Europe in the 14th century.

During medieval times, catapults and related siege machines were the first weapons used for biological warfare. The carcasses of diseased animals or even diseased humans, usually those who had perished from the Black Death, were loaded onto the catapult and then thrown over the castle's walls to infect those barricaded inside. There have even been recorded instances of beehives being catapulted over castle walls.

The last large-scale military use of catapults was during the trench warfare of World War I. During the early stages of the war, catapults were used to throw hand grenades across no man's land into enemy trenches.

Until recently, in England, catapults were used by thrill-seekers as human catapults to experience being catapulted through the air. The practice has been discontinued due to fatalities, when the participants failed to land onto the safety net.

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