Crossbow

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This article is about the weapon. For alternate uses, see Crossbow (disambiguation)

A crossbow is a weapon that fires projectiles called crossbow bolts. It is said to have been invented in China (Zhao Ye, 200 BCE ; Needham, 2004), but this statement can not be absolutely verified. The oldest remains of crossbows can be found in modern China, and the ancient hill tribes are famous for their crossbows up to today. The handheld crossbow played a significant role in European medieval and Chinese warfare and is still used today for sport or hunting. Romans in the Hellenistic era used a device derived from the crossbow known as a ballista.

A crossbow consists of a prod (similar in appearance to a bow) mounted on a stock similar to a rifle stock, which has a mechanism to wind and shoot its bolts. The prod (also called 'lath' in England) is attached to the stock with hemp rope, linen, whipcord, or other strong cording. This cording is called the bridle of the crossbow. Much as a horse's bridle, it tends to loosen over time, and must be carefully respliced when appropriate.

Above the crossbow's stock is a flat section called the shelf or bolt rest, which has a straight groove for the crossbow bolt to rest upon and travel along as it is shot. A crossbow also contains a string which is held in place by a nut when the bolt is loaded and the crossbow is engaged (this position is referred to as being "at full draw"). Typically, the nut is placed at the end of the shelf.

Crossbows were fitted with a trigger, which was later incorporated (along with the stock) into rifles, muskets and other firearms. Triggers are known to have been used on crossbows from the early 1400s. Leonardo da Vinci designed many complicated triggers for crossbows, ultimately producing a "hair trigger" that could be shot with very little finger strength.

1 Differences from regular bows
2 Composition materials
3 History
- 3.1 Use
4 See also
5 References
6 External sources

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Differences from regular bows

The prod of a crossbow is very short compared to that of regular bows, which results in a short draw length that makes crossbows inefficient at storing energy. To compensate for this, crossbows are built to have very heavy draw weights (the tension the string is under when the bow is engaged). The draw weight of a modern crossbow can be up to 300 lbf.

Crossbow bolts do not depend upon lift as arrows do. Crossbow bolts must be made to have consistent weights, as the mechanical process of engaging a bolt forces a more uniform process than that of using a bow and arrow. This consistent performance was part of what made the crossbow historically a significant force in warfare.

Crossbow bolts are also two to three times heavier than arrows. Due to the thickness of a crossbow's prod, it releases energy slower than a bow - so lighter bolts are accelerated to the same speed as heavy bolts, but they have less kinetic energy. Bolts must be sealed with a poof to ensure their consistent weight. They also typically only have two fletches per bolt, instead of the three fletches commonly seen on arrows. This prevents them from snagging on the crossbow nut as they are shot.

There is an optimum weight for bolts, which varies depending on the acceleration system. Some modern crossbows accelerate so fast that very light bolts can be used. Often these crossbows do not operate with a prod, but with elastic fibers tension. Crossbow bolts can be fitted with a variety of heads, but the most common is the quarrel.

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Composition materials

Historically, the prod ("bow") and stock of a crossbow were made of good hardwood, such as oak or hard maple. The central European bows were rather exotic as they were constructed of inlays as well as specialized woods. The strings for a crossbow are typically made of strong fibers that would not tend to fray. According to W. F. Patternson, whipcord was very common; however linen, hemp, and sinew were used as well. Even cotton was tried with some success. In wet areas, twisted mulberry root was occasionally used.

The prod of a crossbow was made of wood or composite materials until the early 15th century when steel began to replace other materials in Europe. The advantage of a simple wooden prod is that the bow as a whole was lighter in weight, easier to span (even by hand), and quicker to discharge. Composite construction, on the other hand, could be made stronger and give the bolt more kinetic energy. Composite prods were made of horn, sinew and wood, and produced much larger draw forces. The Europeans favoured single wood longbows for hand bows, but instead the composite construction was favoured on crossbow prods. Since the draw force could be much more than a soldier was able to pull, these crossbows generally included first a belthook and later a winch device to cock them. Since composite prods involved gluing material together which would have to withstand a great deal of stress, a slow drying time was essential. The strongest glues naturally took longer to dry. It was not uncommon to spend up to six months to a year ensuring a bow was properly dried.

In the later 1400s, steel manufacturing advanced significantly, and was more commonly used in spring production. Prods made from spring steel were very common by the early 1500s, as their performance was more uniform (except in very cold weather). Also around 1400, the use of the crossbow changed, with the butt end of the stock being placed on the shoulder for increased accuracy. By 1650, the crossbow had a stock that we now see being used for rifles, and was used in a similar way (many of the innovations used in today's rifles were first developed on the crossbow). Makers of crossbows (arbalistmeisters) were making quite beautiful crossbow stocks by 1600 - some Belgian designs were as polished as those of modern Olympic rifles.

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History

Image:ChineseCrossbow.JPG

Literary records (Zhao Ye: The Romance of Wu and Yue) place the invention of the crossbow in China during the Warring States period in the kingdom of Chu about 500 BCE. Contemporary writers like Yang Hong and Zhu Feng Han contend that the often cited inventor, Ch'in, just improved upon a trigger mechanism, and that the crossbow may have existed from the seventh century BCE or even much earlier. Archaeological evidence supports the existence of the crossbow in China at the eneolithic/chalcolithic period around 2000 BCE - indeed the oldest remains of crossbows have been found in modern China. As other sources state (Stephen Selby, 2001), it is possible to make much simpler trigger mechanisms than those that have been found on archaeological remains, but these triggers were often made of materials that easily decay (especially wood) and so remains are hard to find.

The handheld crossbow was first improved in ancient China to draw with heavy weights and shoot faster. According to Guinness World Records(2004), the earliest reliable record of crossbow usage is in the Battle of Ma-Ling, Lingyi, China at 341 BC. By the 200s BC, the crossbow (nǔ, 弩) was well developed and quite widely used in China<ref>Invention of the Chinese crossbow</ref>. Crossbows have also been found among the soldiers of the Terracotta Army in the tomb of emperor Qin Shi Huang (260-210 BCE) <ref>Weapons of the terracotta army</ref>.

The first western reference to the crossbow is to the gastraphetes ("belly-bow") of early Hellenistic period (ca. 400 BC). The Romans called the crossbow an arcuballista (hence name "arbalest"). They did not employ it as a massed weapon, but used it as a scout weapon and for hunting. According to book Arma Fennica, the crossbow was used by the Inuits of Greenland. Other sources note its usage in Western Africa from where enslaved inhabitants brought it to America. Light hunting crossbows were traditionally used by the Inuit in Northern America, as well as being found throughout Eurasia and the Indonesian Islands. The crossbow was also often used on horseback, especially in Scandinavia.

The crossbow became a common weapon of war in Europe in the 9th century, and almost completely superseded the hand bows in the 12th century. The Saracens called the crossbow qaws Ferengi, or "Frankish bow", as the Crusaders used the crossbow against the Arab and Turkoman horsemen with remarkable success; the foot crossbowmen could outshoot mounted archers. The Byzantines called the weapon tzaggra. The crossbow also became the weapon of choice for peasants in Europe. The Finnish national epic, Kalevala, depicts Joukahainen ambushing the hero Väinämöinen with a crossbow. The legendary hero Wilhelm Tell supposedly shoot an apple from atop his son's head using a crossbow, and in the process started the war of liberation for Switzerland by ambushing the landreeve Gessler.

The repeating crossbow (Chu-ko-nu) is one of the greatest Chinese innovations on the crossbow. Invented in 2nd Century AD, by the famous Chinese strategist, Zhuge Liang, it was used as late as China-Japan war of 1894-1895 by Manchurian troops.

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Use

Pull lever

Push lever

Ratchet

Windlass

Image:LargeCrossBow.jpg

Image:LargeCrossBow Crank1.jpg

Image:LargeCrossBow Pull.jpg

Crossbows were actively being used in European warfare from 800 to 1550 A.D. They supplanted bows in many European armies for a number of reasons. An expertly handled longbow had greater range, better accuracy and a faster rate of fire than an average crossbow. But the value of the crossbow came in its simplicity: it could be used effectively after a week of training, while a comparable single-shot skill with a longbow could take years. The 100 years war and the mercenary wars in Italy had proven the longbow able to stop horses with knights mounted on them, but unable to stop heavy infantry. With the rise of heavy infantry, the crossbow was a cheap and efficient counterweapon. The use of winches allowed soldiers to use and fire weapons with a draw force far in excess of what they could have handled with a bow. In the later years of the crossbow it had enough kinetic energy to penetrate the armor of a knight with ease when hit squarely: some reached a draw force of nearly 350 lbf (1600 N), compared to the 60-180lbf (300-900 N) draw force for a longbow. Moreover, crossbows could be kept cocked and ready to shoot for some time with little effort, allowing crossbowmen to aim better and to "cover" a target area, while archers could not keep their powerful bows pulled for long periods of time.

Due to the long time required to reload a crossbow, users would sometimes make use of a pavise. Siege arbalests could be even stronger than field arbalests, with up to 1000 lb (4400 N) and be accurate to distance up to 500 m.

Pope Urban II banned the use of crossbow against Christians in 1097, and the Second Lateran Council did the same for arbalests in 1139. The crossbow was seen as unchivalrous and as a threat to social order, since a peasant could kill a noble anonymously; crossbow mercenaries were usually killed immediately on capture, unlike others who might have been ransomed or set free. However, their effectiveness made them an "evil" no one could afford to be without, often in the form of hired foreign mercenaries. Given the great accuracy of the crossbow, it filled many duties that sniper rifles have today.

Crossbows were eventually replaced in warfare by gunpowder weapons. Early guns had slower rates of fire and much worse accuracy than contemporary crossbows.

Modern crossbows are still used for target shooting, military snipers and in some places for hunting, although for the latter a person generally has to have a disability or special license to use one. They are made of the same composite materials as modern bows.

One of the newest developments in crossbow technology is the use of the shoulder-cock. The shoulder-cock is extremely easy to use and has a fast loading time. Using a shoulder-cock, a good crossbowman could reload in under 7 seconds. The average draw force for the shoulder-cock crossbow is 100 lbf (400 N), which is low compared to other crossbows. A good example of a shoulder-cock crossbow is the FX-II crossbow.

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