The Turkish composite bow, like most of the Asiatic composite bows, consists of a wood core sandwiched between a horn belly (the side towards the archer) and sinew back (the side away from the archer). Ears, or siyah, are attached to the tip of each limb to act as static recurves. The handle is built-up in the center, or made as a separate piece with the limbs spliced on. Animal glues such as hide, sinew or fish bladder glue hold it all together. Variations on this basic type of bow were found throughout Asia including Turkey, Persia, India, China and Korea. The various invading hordes from the Asian Steppe were experts at wielding this type of bow, especially from horseback.
The design and construction of the bow itself is a marvel of
engineering. Horn can
compress 4% before yielding, as opposed to only about 1% for wood.
This makes it an ideal material for the highly compressed belly of
the bow. The preferred horn comes from Asiatic water buffalo, but
Gemsbok is presently much more affordable and easier to obtain. The
horn is then split and steam-pressed flat. When hot and moist, horn
becomes very pliable and may be worked readily.
Sinew has about four times the tensile limit as wood, making it an ideal material for the highly stretched back of the bow. Sinew is processed from animal tendons, either from the hind legs or the back-strap. The sinew threads are applied in a matrix of hide glue, and the result is very much like a natural fiber glass.
Using wood for the core, where the tension/compression forces are minimal, is done for weight savings. This allows more of the energy stored in the bow to be used to accelerate the arrow and not the mass of the limbs themselves. The wood core and matching horn face are grooved to double the gluing surface. This also serves to put the glue joint into shear, rather than tension, when the bow is drawn, further increasing its relative strength.
The rigid siyah act as static recurves, loading all of the energy into the middle third of the limb as the bow is drawn. Also, as the bow is drawn the string lifts off of the siyah and the effective string length increases, thus making the bow easier to draw.
Animal glues, such as hide glue, are simply the collagen protein derived by boiling animal parts (hide or sinews) in water and collecting what rises to the surface. Once dried and pulverized, it appears granular and may be stored indefinitely in a sealed container. For use, it is simply re-hydrated until 'plump' and heated. The glue gels as it cools, providing for quick set-up, and until it dries may be re-flowed simply by re-heating the joint. Once fully cured, hide glue is stronger than all but the most advanced space-age adhesives. The one disadvantage to this type of glue is that it is hygroscopic (absorbs moisture from the air). It can be made moisture resistant by the addition of tannin, for example, using a strong tea of white oak bark to hydrate the glue, but excessive humidity will turn such a bow into a limp, useless artifact.
For more information on ancient bows and arrows, check out articles in the Journal of the Society of Archer-Antiquaries.
All pictures and text
Copyright 2003
Originally appeared in
The Mudpuppy
Newsletter of The Barony of Settmour Swamp
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