A kite is an unpowered, heavier-than-air flying device held to the earth by a line. The kite flies because wind resistance causes the air pressure under the kite to be greater than the air pressure above the kite, making the kite rise. The word kite is derived from the name of a type of bird belonging to the hawk family which is know for its graceful, soaring flight.
A kite consists of three basic parts: the body, the line, and the bridle that attaches the line to the body. To enable the user to control the movement of the kite, the bridle must be attached to the body of the kite in at least two places.
Kites were first developed in ancient China. Written references to kites in China date back to 200 B.C. , but they were probably invented at a much earlier time. Kites were probably derived from cloth banners, similar to modern flags, which streamed out in the wind while attached to cords or flexible wooden rods. The first use for kites was probably for signaling at a distance. The Chinese later used kites for numerous purposes, ranging from religious ceremonies to warfare. The earliest kites were built of wood and cloth. Paper was invented around the year 100 A.D. and was soon adapted for use in kites.
Kitemaking soon spread from China to Japan, Korea, Burma (now, Myanmar), and Malaysia, regions where kite flying is still an important part of the local culture. From there it spread to Indonesia, India, and the islands of the Pacific. Eventually, the kitemaking technology was adapted by the Arabs, who in turn brought it to North Africa and Europe.
Written references to kitemaking in Europe date back to 1430 A.D. Early European kites were made of cloth or parchment and sometimes had a long slit with a piece of silk sewn into it to help the kite soar. A pair of diagonal sticks were attached to the cloth to hold it in place. A cord was attached to the kite by a ring sewn into the cloth.
The first description of kitemaking in English appeared in 1654 in a book by John Bate entitled Mysteries of Nature and Art. His instructions are not unlike the methods still used to make homemade kites today. "You must take a piece of linen cloth of a yard or more in length; it must be cut after the form of a pane of glass; fasten two light sticks cross the same, to make it stand at breadth; then smear it over with linseed oil, and liquid varnish tempered together…then tie a small rope of length sufficient to raise it unto what height you shall desire."
European kites existed in a variety of shapes, ranging from lozenges to rectangles. They all required tails for stability, and many homemade kites still have such tails. Commercial kites are usually made in such a way that no tail is required.
Kites were used in meteorology as early as the eighteenth century, when two students at the University of Glasgow named Alexander Wilson and Thomas Melville attached thermometers to kites to study the temperature of the air. Kites were used extensively for studying the weather in the 1830s and 1840s, and continued to be used for this purpose until the middle of the twentieth century, when they were replaced by weather balloons and later by weather satellites.
Innovations in kite design began to appear in the late nineteenth century. In 1891, William A. Eddy, inspired by a Japanese design, invented a diamond-shaped kite, which did not need a tail. In 1893, Lawrence Hargrave invented the box kite, resembling two or more open-ended boxes connected to a wooden frame. Like the diamond kite, the box kite flew well without a tail. Both designs are still commonly used by kitemakers today. The box kite also influenced the design of early aircraft, including the airplane invented by Orville and Wilbur Wright in 1903.
In November 1948, Gertrude and Francis Rogallo applied for a patent on a revolutionary new kind of kite. The patent was issued in March 1951, for the "flexible kite," now usually known as a para-wing. This seemingly simple kite consists of a square of light material (cloth at first, now usually plastic) without any sticks or other parts to hold it in place. Proper length and placement of the cords which make up the bridle enable the para-wing to fly with great stability despite the limpness of its body. Designs similar to the para-wing have been used in parachutes and hang gliders. Military experiments have shown that large versions of this design could be used to carry weapons or vehicles over otherwise impassable terrain. A 4,000 sq ft (372 sq m) para-wing has been used to lift a load of 6,000 lb (2,724 kg).
Homemade kites are usually made of wood and paper or cloth. Homemade para-wing kites are usually made of Mylar, a trade-name for thin sheets of a plastic known as polyethylene terephthalate. This material is extremely strong and very light. The raw materials used to make polyethylene terephthalate are the chemical compounds glycol and dimethyl terephthalate.
Commercial kites are generally made of a strong, light plastic such as nylon. Nylon is the common name for certain types of plastic known as polyamides. Polyamides can be made from a variety of chemical compounds. Nylon-6,6 is the most common form of nylon and is made from the chemical compounds adipic acid and hexamthylenediamine. Another common type of nylon is known as nylon-6 and is made from the chemical compound caprolactam.
The lines attached to the body of the kite are usually made of nylon or cotton. For some large kites, the line is held on a fishing reel, which is made of steel.
The first step in the quality control of kite manufacturing is inspection of the nylon fabric. It must be free from holes and tears, which would damage the ability of the kite to stay aloft. After it is cut, the fabric is inspected to ensure that all pieces have been cut to the proper size and shape. Experienced sewing machine operators inspect the kite at every step of the sewing process to ensure that every piece is sewn into place properly. The position of the bridle line attachments is particularly critical; if they are not properly placed, the kite will be unstable and will fly erratically. Each kite is given a final visual inspection before it is packaged.
Eden, Maxwell. Kiteworks: Exploration in Kite Building and Flying. Sterling Publications, 1989.
Hart, Clive. Kites: An Historical Survey. Frederick A. Praeger, 1967.
Roberts, Keith. Kiteworld. Arbor House, 1986.
Wagenvoord, James. Flying Kites. Macmillan, 1968.
Yolen, Jane. World on a String: The Story of Kites. William Collins and World Publishing, 1968.
— Rose Secrest