make a Boomerang

Boomerang is an object that is designed to fly aerodynamically efficient through the air when thrown by hand. The term usually refers to an object made to follow a circular flight path that returns to the thrower. (Some sources describe all "throw sticks" aerodynamic as a boomerang, separating them into "back" and "nonreturning" category.) Traditional V-shaped design, but newer versions may have irregular shapes or more than two arms.Two components of the design gives a circular boomerang flight capabilities. One of them is the arrangement of the arm, and the other is the airfoil shape that allows guns to the wings. During the flight, the boomerang spins faster (about 10 cycles per second). Profile wings create lift the same effect that makes planes fly. In addition, the spinning motion creates gyroscopic precession, interesting boomerang in the form of a circle. The same effect can be seen with a spinning top: if the axis of the top is not quite vertical, the top toy trip in a circle around the axis.For a successful flight, the boomerang should be disposed of properly. It should be held near the end of one wing to the surface (curved) top facing the pitcher's body. Boomerang should be almost vertical, with the lowest passer's arm. Depending on wind conditions and the design of a particular boomerang, the top may be inclined up to 30 ° to the outside. After drawing the arm back, the pitcher threw the boomerang with boxing movements, much as a baseball pitcher will throw. At the time of its release, the thrower adds snap wrist, as if cracking a whip. Release angle should be between 15 ° horizontal and above. If there is any wind, the boomerang should be disposed of between 30 ° and 90 ° to the right of the wind in-come (or to the left for left-handed pitcher; Right-and left-handed boomerangs are mirror images of each other).As a boomerang flying forward, he began to slowly roll (as opposed to right-hander), finally flying horizontally with the flat side down. When returning to the thrower, was captured safely at chest level, trap it between the sandwich open arms.Recreational throwers simply enjoy playing solitaire catches. Those interested in the competition can choose from a variety of events, including precision (back as close as possible to the point of launch) and durability (make the catch at the five-minute period). Inter-national recording for mileage before returning to the thrower is 780 ft (238 m), on a flight that lasted nearly 22 seconds. The record for maximum time aloft (MTA) is two minutes, 59.94 seconds, the record is not official MTA, which was witnessed but not thrown in a competition sanctioned, is an astounding 17 minutes, six seconds.HistoryDeveloped as a refinement of the boomerang throwing stick carving (kylies) used as a weapon, especially for hunting. Kylie oldest found to date is one formed from mammoth ivory. Found in Poland in 1987, his age was carbondated in about 20,300 years. This 2-ft (60-cm), 2-lb (0.9 kg), gently curved instrument was probably thrown in to kill a deer. A plastic replica has been found to travel an average of 90 ft (27 m) when thrown, despite throwing into head winds increase the range to 123 ft flat (38 m).Kylies used by prehistoric peoples in all parts of the world. Usually made of wood, they are banana shaped, both face each arm carved curved airfoil surface. When thrown, they travel parallel to the ground for distances up to 650 ft (200 m), turning their anger toward the target. Usually 3 ft (0.9 m) long and weigh 5-10 lb (2.3 to 4.6 kg), their effective hunting tool.There is some evidence that the boomerang was developed in several cultural groups. For example, a boomerang-shaped object found in Germany was made of ash wood. Carbon-dated to the era of 2.400 to 2.800 years, preserved enough to allow archaeologists to reconstruct the whole shape. Replication lefty has thrown a boomerang trajectory to produce complete, however, the wing profile is less than optimal, making it difficult to remove successfully. Evidence suggests that the boomerang may also have been developed in Egypt and India.In all regions except Australia, designed for hunters throw spears and bow to shoot, and they stopped using kylies. The aborigines of Australia, however, continued hunting with throwing sticks. Experimenting with the design, the eastern and southern part of the continent that developed boomerangs, they are used primarily for sport. At a meeting of the major tribes, they held a competition based on qualities such as accuracy and speed and quality of return flights. Boomerang is not thrown at predators, although they are sometimes thrown in as bait to lure the bird into the net.The oldest boomerang found in Australia dates to around 14,000 years ago. The origin of the word is uncertain, although it may have come from the cries of "boom-line I-" ("back, stick") that the British colonial interest Dharuk heard screaming when throwing the instrument in 1788. The traditional method to make a boomerang to choose the right piece of curved wood, usually from the part where the roots join the trunk large, making angles 95-110 °. If necessary, the angle between the wing was adjusted by heating and bending it backfire on fire. Aerodynamic profiles are carved out of wood with an ax, a flint smoothed, and polished with sand. The design may be engraved on the surface, for decoration or to enhance the flight characteristics. Timber was sealed with fish oil or paint.Boomerang remains a curiosity relatively obscure until about 1970. A workshop on how to make and throw boomerangs presented by the Smithsonian Institution in Washington, DC. This sparked great enthusiasm for the sport, and the Smithsonian began sponsoring an annual tournament on the National Mall. The first international championship tournament held in 1981.Raw MaterialsVarious materials can be used to make boomerangs. Wood remains one of the most popular because it produces good results, relatively inexpensive, and easy to work. Is generally preferred aircraft grade Finnish or Baltic birch plywood, laminated from thin layers of wood. Sheets of 0.2-in (5-mm) thick will have between five to 10 layers. To protect the wood from moisture, usually covered with a layer of polyurethane.Among synthetic materials that can be used to boomerang is polypropylene, acrylonitrile-butadiene-styrene (ABS) plastic, fiberglass, carbon fiber, linen-phenolic resin laminates and Kevlar para-aramid fibers. Boomerang toy made of urethane foam or cardboard can be used indoors.DesignBecause the spinning action is very important to the performance of a boomerang, there are some basic concepts that should be followed during the design process. However, the basic elements leave much room for creativity, and often backfires makers experimented with an innovative form.When creating a new pattern, designer marks a point in the middle of a piece ofA boomerang.
 
A boomerang.sturdy paper. This marks the first guide shows the center of gravity of the boomerang. As designers continue to sketch backfired, he must be careful to balance the shape around the center of gravity. Another important consideration is that each wing boomerang centerlines must show generally toward the center of gravity (ie, within 10 ° in either direction). So the second set designers make your mark on the paper that the centerlines of the wing. Within the limitations imposed by your sign, the designer can then sketch the basic design or quirky as desired.Once the design is completely withdrawn, the designers cut out of the sheet of paper. With successive patterns hanging from the tip of each wing, the designer can verify that the center of gravity has been planned sufficiently preserved. This would be true if the middle of each wing hang within 30 ° of vertical.Designers seriously looking a more precise method can use more sophisticated techniques, including computer-aided design software.Manufacturing ProcessThe following description focuses on making a V-shaped plywood boomerang Synthetic materials that work the same way, but some produce dust or hazardous vapors when cut or sanded. In this case, dust masks and protective clothing is essential.Formation* 1 sheet of plywood checked flatness. If it is not completely flat, it is oriented so that the concave side of the surface will suit backfires. This significantly increases the power of the boomerang, and it raises a little wingtips for better aerodynamics.* 2 The pattern is placed on the plywood so that the wood grain runs across the end of one arm of the boomerang to the end of the other arm. Pattem outline traced on plywood with a pencil.* 3 A scroll saw, jigsaw, coping saws, band saws, or fret saw is used to cut shapes out of plywood boomerang. This basic piece is called empty.* 4 As an alternative to cutting a blank one piece, two separate wings can be cut, allowing overlapping sections where they will join. Using a router, half the thickness of the cut overlap of each wing. Overlapping sections joined with wood glue and clamped together until the joints stiffen.* 5 The lines were drawn on the top of the blank to indicate areas to be established for the leading and trailing edges of the wings.* 6 Profile of the wing is formed with a belt sander or by hand with a rasp or plane. The upper end portion of each wing down at an angle of 45 °, while the rear wing to left sloping down from 0.04 to 0.08 in (1-2 mm) thick trailing edge. The face of the leading edge is cut back a bit. Formed wingtip to the same thickness as the trailing edge. Various layers of plywood serves as the contour lines that help employees achieve a uniform slope.* 7 shallow part can also be cut from the bottom surface of each wing. For example, it may consist of strips of 2-in (5-cm) long near the end of the wing and behind the leading edge.Finishing* 8 Using the more refined (80-250 grit) sandpaper, surface boomerang carefully smoothed with an orbital sander or by hand.* 9 After spraying the surface with a sanding sealer, fine steel wool used to further smooth the surface. A coat of paint or wood stain followed by one or more layers of clear polyurethane finish.Tuning* 10 boomerang was thrown several times to test the ability of flight. Several types of adjustments can be made to tune boomerang for better performance. For example, the profile of the wing may be adjusted with additional sanding.* 11 different tuning technique to bend the wing, increasing their tips about 0.12 inch (3 mm) above the plane of the point, this is called giving backfired a positive dihedral. It may be necessary to heat the boomerang to make it flexible enough to bend and to make permanent adjustments. This can be done with steam or even microwave ovens.* 12 plays to raise or lower the wing leading edge can also affect the performance of the boomerang.* 13 other tuning techniques including drilling a hole through the wing, cut a slot in the leading edge of the wing, or the drilling of shallow holes into the bottom of the wing and put the tin or brass plugs to gain weight.Quality ControlDuring the manufacturing process, quality backfire periodically checked. Unevenness in the boomerang is not the same as the side or bump will take away from the aerodynamic design. Boomerang comities as approved by the World Boomerang Association and the United States Boomerang Association (USBA). These groups set the standards and rules that everyone must abide by boomerang competitions such as security, skills, and time.FutureBoomerang innovations can be developed in two areas: materials and design. As a newly developed material is strong, durable, and lightweight, making boomerangs will try to use them individually or in combination. For example, a boomerang that flew for more than 17 minutes consisting of two outer layers of the shell of carbon fiber and Kevlar; shell filled with an epoxy resin mixed with phenolic microballoons.Two recent innovations suggest ways that design can be modified to improve aerodynamics. One involved making upper and lower surfaces of the wing trailing edge backfire slightly concave. Usually, the surfaces flat or slightly convex. This design is used for the boomerang which sets the current world record distance. In another example, a boomerang wing tips are cut at an angle that makes them perpendicular to an imaginary line that leads to the center of rotation. Usually, the end of the wing perpendicular to the centerline of the wings. These modifications created by the MTA unofficial record holder.