Composite bow


A composite bow is a bow made from many different materials. Composite bows can be made from any combination of horn, antler, bamboo, wood, or sinew. These materials are typically laminated together with glue.
Materials such as horn or antler are added to composite bows because they have extraordinary compression strength, which compliments the equally phenomenal tensile strength of sinew. This greatly increases the energy-storing potential of a composite bow, relative to its length.
Composite bows are able to be drawn to the same length as bows that are much larger, making them more efficient. However, it is very difficult and time consuming to make a composite bow, and the finished bow is more sensitive to moisture. Materials such as horn and antler are also very heavy, which can affect speed.
It is unclear when and where horn composite bows first originated, but the strongest evidence suggests that they were first developed by sedentary Bronze Age civilizations in Anatolia or Mesopotamia, and then spread to ancient Egypt. The highly mobile Indo-Iranian Andronovo culture was instrumental in spreading the early composite bow to East Asia. The Scythian-style bow was the first composite bow suited for mounted archery, and rapidly became the dominant type of composite bow used by militaries across Europe and Asia for hundreds of years. The Scythian bow was later abandoned in favor of simpler styles with flatter profiles, and all further composite bows in history were based on this prototype.
Composite bows began to be supplanted by guns in the early modern period. In some areas, composite bows survived, and were further developed for leisure purposes. Early modern Turkish bows were specialized for long-distance archery. Composite bows are still made and used in Korea and in China, and the tradition has been revived elsewhere. Modern replicas are available, often incorporating natural and synthetic materials.

Origins and use

It is not known exactly when and where the composite bow originated. It is also uncertain if the composite bow has a single origin, as it may have developed independently in different parts of the world. The composite bow likely originated in the Bronze Age, but it is unclear if it originated in the Early Bronze Age or the Late Bronze Age.
The earliest composite bow shapes are found among the Indo-European early Bronze Age pastoralists in Europe, as well as in western Asia and Arabia, however these bows are likely wood-sinew bows that lack horn components. Reliable evidence suggests that the first composite bows containing horn originated in the Near East, probably Syria, Anatolia, or Mesopotamia, and then spread to Egypt. This culminated in the invention of the angular bow. Several composite bows were found in the tomb of Tutankhamun, who died in 1324 BCE.
The composite bow was spread to East Asia by the Indo-Iranian Andronovo culture as well as the Srubnaya culture.
The Scythian bow, ideally suited to mounted archery, likely evolved from the angular bow, showing similar design and construction methods as the Egyptian bows. As the first form of composite bow ideally suited to mounted archery, it became the dominant shape of composite bow in Europe and Asia until the 1st century AD.
There are strong indications that Greek Bronze Age cultures were using composite bows on a large scale. By the 4th century BCE, chariotry had ceased to have military importance, replaced by cavalry everywhere.
The mounted archer became the archetypal warrior of the steppes and the composite bow was his primary weapon, used to protect the herds, in steppe warfare, and for incursions into settled lands.
Classic tactics for horse-mounted archers included skirmishing: they would approach, shoot, and retreat before any effective response could be made. The term Parthian shot refers to the widespread horse-archer tactic of shooting backwards over the rear of their horses as they retreated. The extremely short length of the composite bow made this very convenient.
Composite bows could be used without difficulty by infantry. The infantry archers of classical Greece and the Roman Empire used composite bows. The military of the Han dynasty utilized composite crossbows, often in infantry square formations, in their many engagements against the Xiongnu. Until 1571, archers with composite bows were a main component of the forces of the Ottoman Empire, but in the Battle of Lepanto in that year, they lost most of these troops and never replaced them.

Construction and materials

The wooden core gives the bow its shape and dimensional stability. It is often made of multiple pieces, joined with animal glue in V-splices, so the wood must accept glue well. Pieced construction allows the sharp bends that many designs require, and the use of woods with different mechanical properties for the bending and non-bending sections.
The wood of the bending part of the limb must endure intense shearing stress, and denser woods such as hard maples are normally used in Turkish bows. Bamboo, and wood of the mulberry family, are traditional in China. Some composite bows have nonbending tips, which need to be stiff and light; they may be made of woods such as Sitka spruce.
A thin layer of horn is glued onto what will be the belly of the bow, the side facing the archer. Water buffalo horn is very suitable, as is horn of several antelopes such as gemsbok, oryx, ibex, and that of Hungarian grey cattle. Goat and sheep horn can also be used. Most forms of cow horn are not suitable, as they soon delaminate with use. The horn can store more energy than wood in compression.
The sinew, soaked in animal glue, is then laid in layers on the back of the bow; the strands of sinew are oriented along the length of the bow. The sinew is normally obtained from the lower legs and back of wild deer or domestic ungulates. Traditionally, ox tendons are considered inferior to wild-game sinews since they have a higher fat content, leading to spoilage. Sinew has greater elastic tension properties than wood, again increasing the amount of energy that can be stored in the bow stave.
Hide glue or gelatin made from fish gas bladders is used to attach layers of sinew to the back of the bow, and to attach the horn belly to the wooden core.
Stiffening laths, if used, are attached. Both horn and laths may be bound and glued with further lengths of sinew. After months of drying, the bow is ready for use. Further finishing may include thin leather or waterproof bark, to protect the bow from moisture, and recent Turkish bows were often highly decorated with colourful paints and gold leaf.
Strings and arrows are essential parts of the weapon system, but no type of either is specifically associated with composite bows throughout their history.

Advantages and disadvantages of composite construction

Advantages

The main advantage of composite bows over self bows is their combination of smaller size with high power. They are therefore more convenient than self bows when the archer is mobile, as from horseback, or from a chariot. Almost all composite bows are also recurve bows as the shape curves away from the archer; this design gives higher draw-weight in the early stages of the archer's draw, storing somewhat more total energy for a given final draw-weight. It would be possible to make a wooden bow that has the same shape, length, and draw-weight as a traditional composite bow, but it could not store the energy, and would break before full draw.
For most practical non-mounted archery purposes, composite construction offers no advantage; "the initial velocity is about the same for all types of bow... within certain limits, the design parameters... appear to be less important than is often claimed." However, they are superior for horsemen and in the specialized art of flight archery: "A combination of many technical factors made the composite flight bow better for flight shooting." The higher arrow velocity is only for well-designed composite bows of high draw-weight. At the weights more usual for modern amateurs, the greater density of horn and sinew compared with wood usually cancels any advantage.

Disadvantages

Constructing composite bows requires much more time and a greater variety of materials than self bows, and the animal glue used can lose strength in humid conditions; the 6th-century Byzantine military manual, the Strategikon, advised the cavalry of the Byzantine army, many of whom were armed with composite bows, to keep their bows in leather cases to keep them dry. Karpowicz suggests that crafting a composite bow may take a week's work, excluding drying time and gathering materials, while a self bow can be made in a day and dried in a week. Peoples living in humid or rainy regions historically have favoured self bows, while those living in temperate, dry, or arid regions have favoured composite bows.
Medieval Europeans favoured self bows as hand bows, but they made composite prods for crossbows. The prods were usually well protected from rain and humidity, which are prevalent in parts of Europe. Ancient Mediterranean civilizations, influenced by Eastern Archery, preferred composite recurve bows, and the Romans manufactured and used them as far north as Britannia.
The civilizations of India used both self bows and composite bows. The Mughals were especially known for their composite bows due to their Turko-Mongol roots. Waterproofing and proper storage of composite bows were essential due to India's extremely wet and humid subtropical climate and plentiful rainfall today.
The civilizations of China also used a combination of self bows, composite recurve bows, and laminated reflex bows. Self bows and laminated bows were preferred in southern China in earlier periods of history due to the region's extremely wet, humid, and rainy subtropical climate. The average rainfall in southern China exceeds, averaging in many areas today.