62,466 research outputs found

    THE ARCHER'S PARADOX

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    INTRODUCTION: The archer's paradox is the fact that an arrow does not fly to its mark along the line represented by its axis. The explanation of the archer's paradox was found by means of high speed spark photography which P. E. Klopsteg undertook in order to secure direct evidence of what an arrow does as it leaves the bow [1]. The impulse normal to the axis of the arrow, caused by the release of the fingers from the string, as well as the column-like force of the string on the arrow during its acceleration, results in a significant bending of the arrow shaft as it transits the bow. This allows the arrow to undulate around the bow handle and follow a straight course towards its target without striking the bow handle. P. E. Klopsteg explained this paradox and provided a qualitative understanding of the reasons for matching arrows to a given bow and archer combination [2]. The objective of our study is to develop the mathematical methods of the archer's paradox

    COORDINATIVE ASPECTS OF ARCHERY - AN APPROACH USING SURFACE-ELECTROMYOGRAPHY

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    The process of a shot in archery can be described as follows: The archer draws the bow, pulls the arrow to the clicker1, fixes in this position and aims. Before he releases the arrow, the archer pulls the arrow through the clicker so that a click can be heard. Shortly after this sound, the archer releases. Immediately before the shot there are changes in the muscle activity of shoulder and back. From a biomechanical point of view, the archer must cope with the release of the balance of force between the external tension and the muscular forces (see Fig. 1) immediately after the shot by means of his neuromuscular system. The quality of the anticipation of the balance's release strongly influences the result: After the release of the hand from the string, which also means the release of the static force balance, the arrow still sticks to the string (Leroyer et al. 1993). Thus each motion of the bow is transferred to the arrow. The goal of the archer is to keep the bow steady during and after the release of the balance up to the moment when the arrow leaves the string

    A cinematographical analysis of two selected methods of drawing the bow

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    A cinematographic study was made of three female advanced archers to examine selected mechanical factors of the draw, anchor, release, and follow-through. Two cameras - one 25 feet directly in front of the archer, and one 20 feet above the ground directly over the archer's head - were used to record the archer's movements. Two of the archers drew using the back muscles as well as the arm and shoulder joint muscles, and one archer used the arm pull. The length of the hold at the anchor position was the only factor examined that seemed to be related to the method of drawing the bow, with the two who drew using their back muscles holding longer than the archer using the arm pull. This did not seem to be influenced by the draw weight of the bow used. The angle of the forearm of the drawing arm to the shaft of the arrow did not seem to be related to the method of drawing the bow, but rather to the length of the third (ring) finger of the archer's drawing hand. Bow movement in the horizontal plane after release was influenced by the alignment of the bow limbs to the arrow shaft prior to release as well as by string hand action at release. One of the archers dropped the bow arm after release, and was found to have started dropping it before the arrow had cleared the bow on one of the seven shots photographed. The action of the bow after release (vertical plane) was also examined

    Optimization of bow and arrow design subject to aerodynamic characteristics

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    Archery is a type of sport that has been practiced for centuries all around the globe whether it is used as war weapon, for hunting animals or just for sport competition. The aim of this research is to come up with the optimization of bow and arrow design subject to aerodynamic characteristics. In order to do that, the stiffness of the bowstring of different material was investigated while the stiffness of different arrow shaft material was analysed. Next, the optimal arrow fletcher shape was developed. Throughout this research, only one bow was used for all shots plus the string material analysis was conducted on one bow only. The design variable for fletcher optimization was set on the type of material, dimension, and fletcher orientation based on aerodynamics performance. Due to time constrain, only three type of shaft material was analysed and the data collection was in the form of arrow speed. The speed of the arrows was measured by using a chronograph. A consistency test also conducted in order to see the hit pattern of the arrow at three different ranges. Interviews with top Malaysian archer in both traditional and modern discipline were conducted to investigate their equipment choices. Parabolic shape has higher speed compared to shield shape. Offset orientation causes the arrow to have tighter group compared to straight orientation. Feather fletcher that is lighter than plastic fletcher produces much faster arrow. Fast Flight string material outrun other string material by produces fastest arrow speed. The aluminium shaft is the fastest based on the experiment but archers prefer carbon due to their physical strength and consistent spine rating

    Nebraska Record Fish

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    Nebraska Record Fish: Rod and Reel Bow and Arrow Underwater Powered Spearing Surface Spearfishin

    Nebraska Record Fish

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    Nebraska Record Fish: Rod and Reel Bow and Arrow Underwater Powered Spearing Surface Spearfishin

    The Bow and Arrow in Sangam Literature

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    Scholars point out that the Sangam period dates back to the Veerayuga period. It is also believed to be the Iron Age. Society in the longest hierarchy of mankind. It can be seen from the association's work that the various types have evolved and evolved into different stages. The association work is not complete and does not belong to the same period, and there is ample evidence to learn about the different ethnic community in the association. Exoduses speak of emotional departmental discipline and Exodus speaks of heroic battles. Songs praising the war also showcase the weapons. Data on tools such as bows and arrows are also available. The bow and arrow are symbolically identified with certain concepts with a social background. The bow and arrow set out to illustrate societal evolution and biological values. The purpose of this article is to discuss the movements of the bow and arrow community, although numerous weapons are found in literary references

    Bow Use in the Great Basin

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    The bow and arrow is a tool with a very long history. In the Old World its use dates back to paleolithic times, with firm evidence in the form of arrow shafts dated to the early ninth millennium b.c. (McEwen, Miller, & Bergman, 1991). More tenuous evidence from projectile points in Africa may push that back as far as 11000 b.c. (Blitz, 1988). The focus of this paper, however, will be the adoption and subsequent use of the bow in the Great Basin region of the West

    ARCHER-BOW-ARROW SYSTEM ADJUSTMENT IN THE VERTICAL PLANE

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    A significant part of bow tuning is vertical adjustment that strives for a zero angle of attack of the arrow. This requires laborious procedures through a lengthy and tedious trial and error phase. A mechanical and mathematical model of bow and arrow geometry in the vertical plane in braced and drawn situations has been constructed and investigated. An asymmetrical scheme. rigid beams, concentrated elastic elements, and non-stretchable string are the main features of the model. Numerical results of the computer simulation are presented in tabular and graphical form. This facilitates the use of the methods by archers and coaches
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