The turko-mongol bow in the picture was the ultimate weapon of war for the thousand year period between the end of the Roman empire and the rise of workable gunpowder weapons and armies trained to use them.
It incorporates some of the same ideas which modern compound bows do. The center part of the bow does not move much when drawn; the ears are doing most of the work and behave something like the cams in a modern compound bow, most of the stored energy being transferred to the arrow. These bows were of laminated wood and animal horn and heavy, and were drawn with thumb-rings as shown which were much like modern release devices, the grooved part of the ring being locked over the bow string and the thumb snapped loose from the two fingers over it to shoot. The Turko-Mongol bow was more efficient than an English longbow and shot an arrow faster. The difference is that the whole frame of the longbow moves, so that stored energy is being transferred back into the frame of the bow instead of into the arrow. In the case of the turko-mongol bow, the center part of the bow does not move much, most of the motion being with the outer "ears" of the bow, which involve less mass.
Somewhere around 1968 - 1970 (basic Allen patent Dec 69) the ancient conception of the bow and arrow was reinvented. The modern compound bow begins by taking the idea of the turko-mongol bow one step further and having most of the movement in question involve an essentially massless wheel or cam instead of the outer ears of the turko-mongol bow. Moreover, the compound bow inverts the normal mechanics of the bow in a manner which makes the bow easier to hold and aim while simultaneously providing more power.
In the case of a 70 lb. longbow, the 70 lbs is at maximum draw. It is difficult to hold and, when you release it, the 70 lbs breaks the arrows inertia and, after the arrow is already moving at any real speed, there is no more than 40 - 50 lbs acting on it. I.e. once the arrow starts moving, the force acting on it is only that of middle draw.
In the case of a 70 lb. compound bow, the 70 lbs. is at middle draw, after which it backs down to about 14 lbs. The archer is holding only the 14 lbs at back-draw, making the bow much easier to aim and, when he releases the arrow, the 14 lbs. breaks the arrows inertia and, after the arrow gains some speed, the full 70 lbs. hits it. The arrow is launched as if from a bow with 70 lbs at middle draw, i.e. as if from a much heavier bow. The basic idea is that the wheels or cams are being held against themselves at full draw, i.e. at an angle to the bow so as to reduce the effort to hold the bow full drawn.
In the 35 years since the compound bow was invented, there has been a rapid progression of technologies, in which the original wheels were replaced by cams and then, for the most part, the original two-wheel/two-cam design was replaced by single cams and idler wheels. Materials have steadily improved, the original wood risers being replaced by aircraft aluminum and now carbon fibre, wood/fibreglass limbs being replaced by improved fibreglass and graphite. Carbonfibre arrows have generally replaced the older aluminum and fibreglass arrows.
With practice, a typical archer can predictably hit a softball-sized target with such a bow at 30 yards, and the arrows are moving fast enough that a deer cannot jump at the sound of the bowstring and escape harm. This is much easier on human ears than rifles and does not spook the entire forest population into the next county. In other words, this modern bow is pretty much the ideal hunting weapon.
There are numerous manufacturers of such bows which are generally viewed as good quality, including Browning, Bowtech, HCA, Hoyt, Darton, and a few others. My own most advanced bow at present is one of the HCA carbonfibre-riser bows, which is basically strong enough that dry-snapping it doesn't hurt it (I don't DO that...). HCA is also selling carbon arrows which are substantially lighter than have been sold previously, while yet stressed for heavy bows. The combination allows for speeds which are approaching 400 fps with their most radical setups; my own little HCA bow is set at 75 lbs and shoots the HCA arrows with normal nocks, vanes, and 75 grain tips at about 330. The damping effect of the carbonfibre riser has to be heard to be believed. Noise levels don't seem to rise above ambient forest noise.
Accessories which that bow uses include two items which I recommend as best current technologies:
The whisker-biscuit arrow rest.
The Impact-Archery CosmicAir front sight, with about 4' of fibreoptic cable.
The bow also uses a string loop which I recommend, and a Schurz peep sight which is accurate when used properly, generally foolproof, and does not require zebra strings or any unusual string technology.
The image above shows a string loop and the Schurz peep sight. The HCA bow comes with a sort of a yuppified thinline grip; I had to wrap a couple of tennis overgrips around it before it felt comfortable to shoot.
At the big outdoor show at Harrisburg Pa in 04, there were three archery items which I thought stood out, i.e. the HCA bows, the Firebrand Technologies bows, and the Timberwolf treestands. The Firebrand bows are also strong enough to shoot the new HCA arrows.
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