The Recurve Bow

The Recurve bow owes its name to the shape of the limbs, the working parts of the bow. When strung, they curve away from the archer back towards the target. This extra curve to the limb increases the energy storage and efficiency of the materials, resulting in greater arrow speed for a given draw weight and a smaller bow.

The modern recurve bow is made up of several components. These include...

The Riser
This is the heart of the bow. The Riser, or handle of the bow is the main component to which all other parts are attached and forms the main body of the bow. Risers are available in a wide range of styles and a range of materials. Beginners bows are usually made from wood or high strength ABS plastics. Intermediate risers tend to be cast or forged metals, and more advanced risers are most often machined from a solid billet of high grade alluminium for great strength while being as light as possible. Recently, top end risers are available that are manufactured entirely from carbon materials. These offer incredibly light weights while maintaining the strength of thier metal counterparts.

The Limbs
These are the working parts of the bow. Most modern bows incorporate the ILF ( International Limb Fit ) system, whereby limbs slot into the ends of the riser with a dovetail mount sliding into place to lock the limb, and the end moving underneath an adjustment bolt to secure it. Limbs are available in a wide range of weights and materials. You can get limbs as light as 15lb for beginners up to 50lb for the heavyweights among us! Limbs are made from multiple laminations of different materials, including wood, glassfibre, carbon and syntactic foams in the more advanced options. Depending on choice, limbs can range from £40 for beginners wooden limbs up to £400 for carbon and foam advanced limbs!

The String
Lets not forget this vital piece of equipment, often overlooked in its importance! Modern bowstrings are manufactured from high strength polymers and fibres such as Dyneema, Spectran, Kevlar in some older strings and Dacron to name a few. These modern materials offer incredible strength at very low weight and thickness. Multiple strands are used to maintain stability and strength, with the end loops and the middle section where the fingers sit wrapped in a material called serving to protect and reinforce these areas from wear.

Arrow Rest and Button
The arrow rest is fitted to the bow window ( that is, the area on the bow that the arrow passes when shot ) and the arrow rests upon in until shot. There are a wide range available but all fulfill the same basic funtion. The Button, also known as a Berger button after its inventor Vic Berger, or the Plunger is a device that is screwed through the bow from the side opposite the arrow. This is the tube that can be seen sticking out on an olympic shooters bow. The purpose for the button is to absorb the sideways movement of the arrow when fired due to the string moving off the fingers ( known as archers paradox ) and to decrease lateral movement of the arrow. While this all sounds complicated it can be easily demonstrated, and can be used to fine tune arrow flight for optimum performance. A button is not neccessary if you do not wish to use one, but they are recommended for the tuning they offer.

The modern recurve is shot in 2 main configurations. Recurve, also called Freestyle Recurve or Olympic recurve as it is the only bow style currently allowed in Olympic competitions. This style allows for accessories to be used to aid the archer. These include stabilisers and sights. Most modern recurve risers are designed to be shot in this manner and will be balanced to perform best when set up with stabilisers and weights.

The other style for the recurve bow is Arco Nudo, better known as Barebow. This limits the user to just a riser, limbs, string and a button if you want one. This style of archery is far more instinctive, akin to longbow shooting but making use of the modern bows efficiency. This style is very popular among field archers.


Asiatic Reflex Bow

Europeans encountered the many forms of this bow as they came into contact with the nomadic peoples of the vast Eurasian steppe. Throughout the ages, wave after wave of these horse archer based armies rode into settled eastern Europe and brought great destruction. From the ancient Scythians to the Mongols and finally the Ottoman Turks, the composite bow was the main weapon.
The Scythians are generally recognised as introducing the reflex horn bow, though composite bow types were used by the ancient Egyptians and Assyrians.

The Scythian bow was of typical 'Cupid' shape, featuring highly recurved limb tips. Constructed differently to later Asiatics, it was often made up of many horn pieces attached to a wooden core, the entire thing cross spirally bound with sinew.

The Hunnic bow was larger. It had wide limbs to which rigid tips (siyah) were fitted. Many finds have shown amazing craftsmanship with splices and bone stiffening plates at the siyah and handle section. The belly of the limbs were covered by a horn strip or strips and the back with sinew. This made the bow very powerful and the arrowheads became bigger as a result.

As Hunnic power waned, another Turkic federation arrived, the Avars. They settled the Carpathian basin but were around for longer, some 200 years, during which time their bows evolved from something similar to the Hunnic design into a shorter bow with more reflex in the siyahs.Again, their arrowheads were large.

The Magyars were the last nomadic people to settle this area, with similar bows featuring lighter siyahs of typical Magyar shape. Various horse archers, Khazars, Pechenegs, Qipchaqs raided from the western steppe until utter devastation arrived as the Mongols invaded Russia and Hungary. The typical 'Mongol' design with string bridges is actually more of a later Chinese 'manchu' innovation.
The Asiatic reflex bow reached its zenith with the elaborate Turkish bow where the recurved siyahs are spliced well into the limb section forming a rigid and a working part in the limbs. Unstrung, these bows were pretzel shaped and when strung they become a short deflex, reflex shape. Traditionally there were three different types...war, target and flight, each with subtle differences.
From the time of the Avars, thumb rings began to appear which would suggest this became the predominant method of drawing these bows, however this was by no means exclusive, the Huns before them left no evidence of thumb rings and the Magyars are believed to have used their bows in the western fashion. Turkish archery, Chinese and Korean all feature the thumb draw.

There are many modern reproductions of these bows using modern materials like glass fibre and TRH laminates to achieve similar performance to the sinew and horn of the originals, this makes the bows very affordable. A true composite made in the traditional way is very expensive and requires some knowledge to maintain.

Compound

A compound bow is a modern bow that uses a levering system, usually of cables and pulleys, to bend the limbs.

The limbs of a compound bow are usually much stiffer than those of a recurve bow or longbow. This limb stiffness makes the compound bow more energy-efficient than other bows, but the limbs are too stiff to be drawn comfortably with a string attached directly to them. The compound bow has its string attached to pulleys (cams), and one or both of the pulleys have one or more cables attached to the opposite limb. When the string is drawn back, the string causes the pulleys to turn. This causes the pulleys to pull the cables, which in turn causes the limbs to bend and thus store energy.

The use of this levering system gives the compound bow a characteristic draw-force curve which rises to a peak weight and then "lets off" to a lower holding weight.

Technical advantages

• As the bow is drawn, the draw weight increases to a peak and then "lets off". The let-off is usually between 65% and 80% of the peak weight, and one manufacturer (Concept Archery) produces a compound bow with 99% let-off. The "let off" is a term that describes what happens as the cam rolls all the way over. The photo on the right shows the axle attaching the limb to cam is mounted at the edge of the cam as opposed to the center. As the string is drawn the cam turns and imparts force to compress the limb. Once the cam turns all the way around the least amount of force needs to be applied to the string to keep the limbs bent. This is known as "let off". This enables the archer to hold the bow fully drawn and take more time to aim.
• This let-off enables the archer to accurately shoot a bow with a much higher peak draw weight than most could manage with a longbow or recurve.
• When a compound bow is drawn, the limbs are pulled in toward each other, unlike a longbow or recurve where the limbs flex in the direction of the bow string. This difference allows modern compounds to have limbs that are horizontal instead of angled. The horizontal limb configuration minimizes the amount of vibration felt by the shooter when the arrow is released.
• The bow is resilient to temperature and humidity changes giving the bow superior accuracy, velocity, and distance in comparison to bows made of natural materials.
• The pulley system usually will include some rubber-covered blocks that act as draw-stops. These provide a solid "wall" that the archer can draw against. These draw stops can be adjusted to suit the archer's optimum draw-length. This helps the archer achieve a consistent anchor point and a consistent amount of force imparted to the arrow on every shot, further increasing accuracy.
• The design of the pulleys (cams) directly controls the acceleration of the arrow. What is termed a "soft cam" will accelerate the arrow more gently than a "harder" cam. Novice archers will typically shoot a soft cam whereas a more advanced archer may choose to use a harder cam to gain speed. Bows can be had with a variety of cams, in a full spectrum from soft to hard.
• Some pulley systems use a single cam at the bottom of the bow and a balanced wheel at the top of the bow instead of two identical cams. This design eliminates the need for buss cables and instead uses a single string that begins at the cam on the bottom of the bow, travels over the wheel on top, around the bottom cam again, and ends attaching to the top limb.

Full details of the different bow styles and the restrictions and regulations for each can be found in the GNAS rulebook, which is available to download from www.gnas.org