Kite

A kite is a flying tethered man-made object. The necessary lift that makes the kite fly is generated when airflow over and under the kite creates low pressure above the kite and high pressure below it. In addition to the lift, this deflection generates horizontal drag along the direction of the wind. This drag is opposed with the tension of one or more lines held by the operator of the kite. Kites held with more than one line can be steered by pulling the different lines with different strength.

History

The kites of history can be traced back thousands of years to when kites first originated in China. The initial usage of kites was purely military: they were a communication tool. Different messages were communicated mainly via different colored kites during the day. At night, the message communicated was very limited in comparison to those during the day because the lanterns carried by the kite could not produce different lights. In extremely rare occasions, giant kites carrying aerial observers were also deployed in reconnaissance roles. Gradually, kites became a popular form of recreation as well as art. With the advent of gunpowder, kites were occasionally flown for bombing missions after the Yuan Dynasty, delivering explosives to targets that were out of reach of cannons and arrows, such as those on the opposite slope of a mountain.

Today, in addition to kites that are mainly flown for recreation, art or practical use, there are power kites or traction kites. These are steer-able kites designed to generate substantial excess lift and a pull that can be applied in related activities such as kite surfing, kite land boarding or kite bugging.

Materials

Kites typically consist of one or more spars (sticks) to which a paper or fabric sail is attached, although some, such as foil kites, have no spars at all. Classic kites use bamboo, rattan, or some other strong but flexible wood for the spars, paper or light fabrics such as silk for the sails, and are flown on string or twine. Modern kites use synthetic materials, such as rip stop nylon or more exotic fabrics for the sails, fiberglass or carbon fiber for the spars and Dacron or Dyneema for the kite lines.

Kites can be designed with many different shapes, forms, and sizes. They can take the form of flat geometric designs, box kites and other three-dimensional forms, or modern spar-less inflatable designs. Kites flown by children are often simple geometric forms (for example, the diamond). In Asia, children fly dried symmetrical leaves on sewing thread and sled-style kites made from sheets of folded writing paper.

Chinese kite designs often emulate flying insects, birds, and other beasts, both real and mythical. The finest Chinese kites are made from split bamboo (usually golden bamboo), covered with silk, and hand painted. On larger kites, clever hinges and latches allow the kite to be disassembled and compactly folded for storage or transport. Cheaper mass-produced kites are often made from printed polyester rather than silk.

Tails are used for some single-line kite designs to keep the kite's nose pointing into the wind. Spinners and spin socks can be attached to the flying line for visual effect. There are rotating wind socks which spin like a turbine. On large display kites these tails, spinners and spin socks can be 50 feet long or more.

Modern acrobatic kites use two or four lines to allow fine control of the kite's angle to the wind. Traction kites may have an additional line to de-power the kite and quick-release mechanisms to disengage flyer and kite in an emergency.

A recent addition to the kite family is the rotor kite. This type of kite consists of a rotor or rotors much like the rotors found on helicopters and auto gyros. In a proper wind the rotors spin and create lift. This type of kite requires two control lines, one for each hand.

Practical & Cultural Uses

Kites have been used for military uses in the past, both for delivery of messages and munitions, and for observation, by lifting an observer above the field of battle, and by using kite aerial photography.

Kites have also been used for scientific purposes, such as Benjamin Franklin's famous (but dangerous) experiment proving that lightning is electricity. Kites were the precursors to aircraft, and were instrumental in the development of early flying craft. Alexander Graham Bell experimented with very large man-carrying kites, as did the Wright brothers and Lawrence Hargrave.

Another practical use to which kites have been put is for fishing.

Kites can be also used for radio technical purposes, either by kites carrying antennas or by using a kite, which carries up an antenna wire ( for MF, LF or VLF-transmitters). This was done sometimes in the past, for example for the reception station of the first transatlantic transmission by Marconi. However captive balloons may be more convenient for such experiments, because kite carried antennas require sometimes running when there is no wind, which may be not always possible with the heavy equipment and a ground conductor. It must be taken into account at such experiments, that a conductor carried up by a kite in the sky can lead due to the earth's electrostatic field a high voltage toward ground, which can endanger people and equipment, if not suitable precautions is done.

Kites can be also used as light effect carrier, for example by carrying light sticks or battery powered light effects.

Kite flying is very popular in the People's Republic of China, Korea, Japan, Pakistan, India, Bangladesh, Thailand, and many other Asian countries. In all of these countries 'kite fighting', in which kite fighters try to snag each other's kites or cut other kites down, is popular. In Afghanistan this is known as Gudiparan Bazi. Some kite fighters pass their strings through a mixture of ground glass powder and glue. The resulting strings are very abrasive and can sever the competitor's strings. However, this practice is dangerous since the abrasive strings can also injure people.

In recent years, multi-line kite flying has developed into a sport, with competitions for precision flying and for the artistic interpretation of music. Kite surfing has developed into a competitive sport with several professional world circuits.

Kite festivals are a popular form of entertainment throughout the world. They include small local events, traditional festivals which have been held for hundreds of years and major International Festivals which bring in kite flyers from overseas to display their unique art kites and demonstrate the latest technical kites.

The Indian festival of Makar Sankranti is devoted to kite flying in some states where it is a public holiday. This spring festival is celebrated every January 14 (or January 15 on leap years), with millions of people flying kites all over northern India. The cities of Ahmedabad and Jaipur are particularly notable for their kite fighting festivals. Highly maneuverable single-string paper and bamboo kites are flown from the rooftops while using line friction in an attempt to cut each other's kite lines, either by letting the line loose at high speed or by pulling the line in a fast and repeated manner. The activity is not without risk as the line is treated to be abrasive and flyers can, and occasionally do, fall from the rooftops. In some Indian cities kite flying/fighting is an important part of other celebrations, including Republic Day, Independence Day, Raksha Bandhan, and Janmashtami.

In Greece, flying kites is a tradition for Clean Monday, the first day of Lent.

During the Taliban rule in Afghanistan, kite flying was banned, among various other recreations.

In Pakistan, kite flying is a ritual for the spring festival known as Basant. However, kite flying is currently banned as some kite fliers engage in kite battles by coating their strings with glass or shards of metal, leading to injuries and death. Kite battle is a very popular sport in Pakistan, mainly centered in Lahore people spend thousands of dollars in preparing different types of kites and threads best suited to battle. The kites that are manufactured for battling are very different from the conventional kites as they are especially designed and made for this purpose. Kup, Patang, Guda, Nakhlaoo, etc are some of the kites used in the battle and they vary in balance, weight and speed through the air. Threads for kite battling are manufactured using especial glues, chemicals and crushed glass and are numbered based on their ability to cut other threads and to handle kite's weight. Kite Battle is an art and the more experienced a person is in this art the more likely he is to win the battle. It is a very popular social event in Pakistan that happens once a year and the festivities are worth seeing.

In Guyana, on Easter Weekend thousands turn out for mass kite flying. In the capital city of Georgetown the massive sea wall protecting the city from the Atlantic ocean is filled with throngs of families picnicking and flying kites of all shapes and colors. Many participate in kite flying competitions.

Weifang (Shandong, China) promotes itself as the Kite Capital of the World. It hosts an annual International Kite Festival on the large salt flats south of the city.

The world kite museum in Weifang is the largest kite museum in the world, the building has a display area of 8100 meter square. There are several Kite Museums in Japan and others in England, Malaysia, Indonesia, Taiwan, Thailand and the USA.

Safety Issues

Never let a kite fly in the neighborhood of power lines and radio stations, especially those using mast radiators. Be careful with experiments with conductive ropes, because these can lead high voltages toward grounds due to the earth's electric field. Of course such kites are especially dangerous, when running into a power line or a mast radiator. Never let a kite fly during a thunderstorm or in the neighborhood of an airport. Never let small children hold a big kite on a windy day by themselves. There have been cases in which children were lifted into the air.