Kites have been objects of interest and fascination to people throughout the world for at least 2000 years. Some people think that kites may have been invented even earlier, suggesting that kites were being flown in China as long ago as 1000 BC. Unless new information comes to light, we have no real way of determining when they were invented, who invented them, or even which country they were first used in. Kites are normally made from light and quite fragile materials, and we have very few actual examples of kites that are more than two hundred years old. Unlike other artifacts such as pots and stone or metal tools, almost everything used to make a kite could rot, or be burnt. Archeologists find out much of what they know about a culture from sources such as rubbish tips. Kites would not last long in this sort of environment. As we don't have the actual kites, we have to rely on traditions, legends, illustrations and documents to chart the historical development of kites.
It is currently thought that kites may have been independently invented in both China and Malaysia, and that this new invention then spread through the rest of Asia from these two countries. There certainly is documentary evidence to suggest that kites were being flown in China as long ago as 200 BC. when a general in the Han dynasty is recorded as having used a kite as an instrument of war, by using it as a method of determining the correct distance to dig a tunnel to enter a palace and end a siege. Other Chinese legends relate how kites were used to lift fireworks in order to terrify an opposing army, and how they were used to lift observers before a battle. Other uses for kites in Asia included a novel way of fishing (also practised in New Zealand), scaring birds from crops, as a way of lifting construction materials to the tops of buildings, and as a toy. In some Asian countries the kite had considerable religious significance. In Korea, newly born children had kites flown and released for them, taking away any bad luck they had been born with. Kites were flown by farmers in Thailand at the time of the monsoon, to ask the gods to make the monsoon winds blow long enough to prevent all the rain falling on their crops and flooding them.
Japanese legends describe how a thief attempted to steal golden scales from a statue of a dolphin on the roof of Nagoya Castle, by using a kite to lift him over the walls and onto the roof without alerting the guards. His scheme failed, and he and his family were put to death by being boiled in oil. Japan became an important focal point for kites because of its geographical location. They were brought to Japan from China by Buddhist missionaries in the seventh century. From here kites spread throughout the Pacific region, carried by Japanese traders and explorers.
Kites were introduced to Europe by explorers returning from Asia. Marco Polo, an Italian explorer who returned from China in 1295, wrote remarkably accurate accounts of the construction of kites, as well as how they were flown. The first known reference to kite flying in Europe appears in a manuscript about military technology, written in 1405. Another text, written in 1430, describes how to make a kite from parchment, and explains how to connect the flying line to different points on the kite in order for the kite to fly well in a variety of wind conditions. Two other books, written in 1589 and 1634 both recommend using kites to lift fireworks at night. An illustration of the town of Middelburg, Holland, made in 1618, shows children flying kites of the diamond shape so common today. In Europe, unlike Asia, kites were regarded simply as harmless toys for children to play with. In the following few centuries that view was to change dramatically.
In eighteenth century Europe the kite showed its usefulness as a scientific instrument. In 1749 a Scottish meteorologist named Alexander Wilson used kites to lift thermometers to a height of 3000 feet to measure temperature variations at altitude. Three years later, Benjamin Franklin used a kite to demonstrate that lightning was similar to the static electricity that scientists were experimenting with at the time. By flying a kite in an electrical storm he was able to observe sparks coming from a key he had suspended from the flying line. Until that time there had been no direct evidence that lightning was an electric current travelling from the ground to the storm cloud. Franklin's experiments led to the development of the lightning conductor, and placed him so high in the regard of the French people that he was able to travel to France during the American war of independence and obtain financial and military aid for the Americans.
Sir George Cayley experimented with kites between 1799 and 1809 in the quest to develop a heavier-than-air flying machine capable of carrying a passenger. He was the first person to describe scientifically the problems that would have to be overcome before man would fly in such a machine.
From kites, Cayley moved to gliders that incorporated two kite-shaped wings. His experiments culminated, in 1853, in a full sized glider that supported the weight of one of his servants on a flight that lasted perhaps 40 seconds (after the flight the coachman promptly resigned). Cayley had identified the separate properties of lift, thrust and drag, and made a number of prophetic suggestions about what he called "aerial navigation".
By 1826, George Pocock had patented a four stringed kite used for pulling carriages. The four strings allowed the kite to be controlled so that the carriage it pulled behaved much like a sailboat, and could even tack into the wind. The carriage apparently was capable of reaching speeds of 30 km/h.
Through the latter half of the nineteenth century a number of people experimented with kites as a lifesaving device. It was anticipated that some of these would be carried on the ship, and flown onto the lee shore if the ship was wrecked. Once the kite had been retrieved by people on the shore, heavier lines could be drawn out by the kite's flying line, until a cable strong enough to carry the weight of an adult could be passed from the ship to the shore, and a rescue of the crew and passengers effected by a breeches buoy, basically a seat suspended from a pulley that could be pulled along a supporting line. Whilst the idea is good, there is no recorded rescue using these methods.
In 1833, a British meteorologist, E. D. Archibold, started using kites to lift anemometers to measure wind speed at various altitudes. Meteorological observatories around the world used kites to lift instruments thousands of feet into the air. This gave a great deal of information about the atmosphere, and vastly improved the weather forecasting of the time. Kites were to continue in this role until the mid 1930s, when aircraft and radiosonde balloons finally replaced them. In 1887, Archibold was the first person to take an aerial photograph from a kite, an application that is still practised today. Kites have been used as a cheap alternative method of obtaining aerial photographs of archeological sites, reefs, and the remains of shipwrecks. A photograph taken from even a comparatively short distance above ground level can show details not readily apparent from the ground.
By the late nineteenth century kites were being seen as serious scientific instruments. Kites were seen as a good starting point in the development of powered, heavier-than-air flying machines. Potential aeroplane builders were tackling the problems of powered flight in a more disciplined manner, making small steps forward, and discovering their new craft as they went along. Rather than trying to create a flying machine in one step, the more careful experimenters worked on one problem at a time, solving each small part of the puzzle and then, and only then, bringing all the parts together in an attempt to build a working aircraft. There were still many people who did not believe that it was possible for a heavier-than-air machine to fly, amongst them being Professor Simon Newcomb (a well-respected astronomer and, in 1903, the only American since Benjamin Franklin to be made an Associate of the Institute of France) and Rear Admiral George Melville, chief engineer for the United States Navy. Even after the Wright brothers had flown, there were many people saying that powered flight was impossible. In hindsight, it seems strange that such a world changing event was virtually ignored until several years after the fact.
Throughout Europe and America, experiments were being undertaken to determine the best sort of design for powered aircraft. The Wright brothers were by no means the only people trying to build an aeroplane; they were simply the first to achieve powered and controllable flight. There were still many fanciful designs being touted as the solution to the problem of powered flight (human powered, flapping wings built onto a bicycle being but one example), but in the main the advocates of powered flight were making gradual but definite progress towards overcoming the intricacies of lift, thrust, drag, stability, and control. Lawrence Hargrave experimented near Sydney in the 1890s with a number of kite designs. He finally settled upon what he called a cellular, or box, kite. He was looking for a stable lifting surface, to which he could add an engine. His experiments led to the development of the cambered aerofoil, a feature that generated much more lift than a flat surface. Put simply, a curved wing surface causes the air traveling over the upper surface to move faster, and travel further, than the air passing along the lower surface of the wing. The air passing over the top surface has a slightly reduced pressure. The greater pressure below the wing exerts an upwards force, called lift, and within certain limits increases with airspeed.
Some of Hargrave's later "gliding kites" were so efficient that they flew at angles of up to 110 degrees. The kite could well be further into the wind than its tether point, which caused a problem if the wind dropped. Hargrave solved this problem by flying this style of kite from a trapeze-like structure, which prevented the kite from reaching the ground if the wind did ease at all.
Most kites fly at angle of less than 50 degrees above the horizon. Efficient kites normally fly at angles of up to 70 degrees. The reason Hargrave's gliding kites flew so well was due to the shape of the wing he developed. It was shaped very much like the cross section of a modern aeroplane wing, with a slight reflex curve at the trailing edge, producing enough just enough drag to stop the kite falling forwards into the wind.
The cambered aerofoil is the basis of the shape of all aircraft wings today. In his quest for a light power source he also invented the rotary engine. Unfortunately, he was unable to overcome the weight problems that beset so many of the early aviation pioneers, and his dream of a full sized, powered box kite never came to pass. In the course of his research he presented 23 papers and exhibitions to the Royal Society of New South Wales on aviation related topics. Hargrave was more interested in solving the problem of powered flight than in being the person to do it. He did not patent any of his inventions, preferring their benefits to be available to all researchers into the development of the aeroplane. In Australia, his achievements are acknowledged by a statue at Stanwell Park, New South Wales, where he carried out his experiments, his likeness, and some of his gliders may be seen on one side of our twenty dollar note, and the engineering and science library at Monash University is named after him. Ironically, the only museum Hargrave was able to pursuade to display his collection of revolutionary kites was in Berlin. His kites, which had helped in the development of powered flight, were destroyed in the bombing of Germany during the second world war.
The Wright brothers eventually overcame these weight problems and flew an aeroplane of their own design in 1903. This was the climax of several years of experimentation using kites and gliders. The wing warping system they used to control their aeroplane had been developed by flying their smaller versions as kites, and twisting the wings with four lines from the ground. Because of their extensive flying of their designs as kites, and their use of wind tunnels to test ideas about wings and propellers, they were able to collect a great deal of information about the stability of their designs, as well as the amount of lift the glider developed for a given wind. This gave them invaluable information about the necessary size and curvature for the wings of their 1903 "flyer".
Alexander Graham Bell was also trying to invent the first powered aeroplane. He knew of the work being undertaken by Hargrave, and he also experimented with kites to determine the most suitable lifting surface. He finally settled on a cellular kite made of regular tetrahedrons (the shape is best known now as that of the tetra pack that Sunny Boys and similar icy poles come in, a "pyramid" with four triangular sides).
Later, he and a number of like minded people set up an association with the express purpose of developing an aeroplane. This association included Tom Selfridge, who later became the first person to die in an aeroplane, when he and Wilbur Wright crashed whilst conducting trials for the United Stated Army, and Glenn Curtis, who later became one of the first aircraft manufacturers in America. Curtis later had to defend himself in court against the Wright brothers, who claimed an exclusive patent on the aeroplane.
Kites were used as an observation device during both the first and second world wars. They were used as a means of increasing the range of visibility by German submarines during both of these wars. At water level an observer might be able to see 8 kilometers, but by using a kite to lift that observer to a height of 400 feet, visibility could be increased to 40 kilometers. When keeping a lookout for enemy ships such an increase of range was definitely an advantage. During the second world war, kites were supplied as standard equipment in life rafts on British and Australian aircraft. If the raft had to be used, the kite could be used to lift the antennae of an emergency radio transmitter. The kite was also used as an airborne sail; although the speed of the raft through the water was quite low, it did help to stabilize the boat in rough seas. Kites with two control lines were developed by a U. S. Navy Commander during the second world war as a means of training naval antiaircraft gunners. Paul Garber's kite was highly manoeuvrable, and was used in target practice. The kite was said to be quite hard to hit as it moved around the sky at the command of its "pilot" who was safely on the ground. Paul Garber had seen the Wright brothers demonstrate their aircraft to the US. Army in 1909, and later became the curator of the Smithsonian Institute, which holds the largest collection of aviation related artifacts in the world.
Kites again attracted attention in the 1950s and 1960s when Francis Rogallo developed a completely flexible kite, with no rigid supporting spars. Instead of spars, this kite uses the wind itself to hold it open and maintain its shape. Rogallo was an aeronautical engineer working for NASA. He was searching for a controllable recovery system for spacecraft. This kite was the first to be developed with the assistance of wind tunnel testing, and is an indication of how far kites have come since they were simply a child's toy. The "Rogallo wing", rather than being used just as a kite, has been put to numerous uses by the American military, and is the basis for hang gliders, and through them, for many of the ultralight aircraft designs being flown today.
Another recent and widely used kite is the parafoil. It too has no spars, sticks, or other form of rigid bracing. It is a true aerofoil, using the force of the wind to inflate the kite and maintain its shape. Of all kite designs, this style gives the greatest amount of lift known to date. This design has been developed into steerable parachutes, and is the basis of the paraglider, a non rigid hang glider. With the development of the parafoil, the evolution of the kite has undergone a new twist. Rather than aeroplanes imitating the shape and form of kites, as happened at the end of the last and the beginning of this century, kites are now starting to imitate the form of the aeroplane.
Manoeuvrable kites.
Kites have undergone a resurgence of interest recently. This is due mainly to the development of "sport kites". These kites use two lines rather than one, and may be steered around the sky, often at speeds in excess of 100 kilometers per hour. Kites have also been developed which use four lines, allowing the user to alter the angle the kite presents to the wind, and so control forward and backward motion of the kite. As wonderful as these kites are, manoeuvrable kites are not new. They have been used for centuries in one form or another around the world.
The oldest form of manoeuvrable kite was developed in Asia, and uses one string rather than two to control it. Traditionally this sort of kite is made from tissue paper and bamboo. It is thought that it originally developed in China, and then spread throughout the rest of Asia, carried by explorers and Buddhist monks. This kite is made of flexible materials, and is manoeuvered by pulling in or releasing line. When the line is pulled in the kite bends at the wingtips and becomes stable. In its bowed state it will fly in a straight line. When line is released the kite becomes flat, and unstable. It will then tumble or spin. When the kite is pointing in the direction the flier wants it to go, line is pulled in, bowing the kite again and causing it to fly in a straight line along its new course. The amount of control over a kite of this style depends upon the skills of the flier, and competitions to see who has the most skill are very common in Asia. This competition takes the form of a fight. The flying line, normally button thread, has part of its length coated with a mixture of glue and powdered glass or pottery, making the line extremely abrasive. During the fight both contestants attempt to manoeuver their kites around the flying line of their opposition and when this has been achieved a sawing motion is all that is needed to wear through their opponent's flying line. For this reason, this style of kite is commonly called a fighting kite.
More general contests, or festivals, also take place, especially in India. The largest, and oldest, kite festival in the world takes place in Ahmedabad on the 14th of January of every year. This festival is a free-for-all, with perhaps 100 000 kites in the sky at once, all trying to cut each other down. The festival has been celebrated for centuries, at the time that the winter solstice has passed and the sun has again climbed above the constellation of Capricorn. The festival is called Makar Sankranti, which means "the conclusion of Capricorn". Tales of kite fighting are found in the Sanskrit religious writings of the Veda and in the epic, the Ramayana. The importance of kites in India is suggested by the Hindi language, which has more than 100 different words for kite.
Thailand, Malaysia, Japan and Korea also have their own kite fighting traditions, as well as their own traditional kite designs. The fighting kites of Japan are normally rectangular or hexagonal and can be big enough to require teams of up to 50 men to control them. It has been suggested that fighting kites developed in Japan as a method of solving disputes between neighbouring villages, as a sort of aerial trial by combat. The city of Nagasaki, one of the only points of contacts between Japan and the early European explorers during the time that Japan maintained an isolationist policy, has a traditional fighting kite called the Hata. It is very similar in shape to the Indian fighter, and is traditionally painted in the red, white and blue colour scheme of the Dutch flag, and the English translation of Hata means flag. Because the tradition of flying this style of kite in Japan is only found around Nagasaki, it is commonly thought that the kite derives from Indian fighters brought to Japan by Dutch explorers and merchants.
Multiple line kites aren't new in Europe either. By 1826 George Pocock had used 4 stringed kites to pull carriages through the English countryside. These flying lines were used to allow the kites to be manoeuvered like the sails of a boat, and, just like a sailboat, his kite-drawn vehicle could actually tack into the wind. Other kites using more than one line were developed later in the nineteenth century, mainly as devices for carrying rescue equipment to shipwrecks, but it wasn't until the Second World War that kites using two lines were flown in the manner we are accustomed to today. Paul Garber's Navy Target Kite could be controlled by means of a rudder attached to the back of the kite and was used to give gunners on ships practice against a moving target. By the end of the war over 300,000 of the kites had been distributed amongst American military forces around the world.
In the 1960s a number of dual control kites came on to the market but it wasn't until 1972, when the Peter Powell Stunt Kite was released that "stunt kites" became really popular. This diamond shaped kite was relatively cheap, was easy to fly, and used an extremely long, inflatable tail that allowed people to "sign write" with their kite. It originally used aluminium spars and a plastic sail but later models used fibreglass spars and a ripstop nylon sail, for increased durability. This kite is still in production today and remains a very popular design.
Since the development of the Peter Powell kite there have been many other innovations. One style of kite that has developed is called the Flexifoil, basically a kite shaped like an aeroplane wing. Although very similar in design to a parafoil, it differs in that it has no fins or keels and instead has a spar running along the front edge of the kite, to hold it open. This kite develops incredible amounts of lift, and can fly in an arc across the wind at speeds well in excess of 160 kilometers per hour. As the speed of this kite increases, so does the amount of lift. Large versions of this kite easily drag people across flying fields, and a recent innovation has been to water-ski behind this style of kite.
The most common style of stunt kite is based on the delta wing. Shaped like hang gliders, these kites make use of materials initially developed by the aerospace industry for high performance aeroplanes and spacecraft. Materials such as kevlar and spectra have properties such as very low stretch factors, and remarkable strength to diameter ratios. Kevlar is used in the production of bullet proof vests, whilst spectra is used in the tethers astronauts use when they work outside their spacecraft. These materials are also used in the manufacture of flying lines for high performance kites. A flying line made of spectra no thicker than ordinary sewing thread has a breaking strain of over 50 kilograms, and will stretch less than one percent of its length. A nylon line of similar breaking strain would be around six times as thick, and would have a stretch factor of about twenty percent. The spars used in many high performance kites are made from carbon fibre, a non-metallic material developed for use in Stealth aircraft, as it doesn't show up on radar. Many other uses have been found for these sorts of materials, as they have become more readily available and costs have been reduced.
The most recent development in kites has been the reintroduction of kites with four lines. These "quad line" kites can be flown forwards, backwards, or sidewards, and may even be made to hover. The space-age materials are new, but the idea isn't; the Wright brothers used four lines on the models they built to test their ideas about wing warping. The flier holds two handles with lines attached to the top and bottom of both of them. Twisting the handles forwards or backwards alters the angle of the kite, and it is possible to use the whole kite as a sort of combination elevator and aileron, and so alter the angle that one or both sides of the kite meets the wind. By pulling the top of the kite further into the wind, the kite will fly forwards. Pulling the bottom of the kite further into the wind will cause the kite to fly backwards. If the bottom of one side of the kite is pulled into the wind, the kite will turn in that direction, as this side of the kite no longer generates as much lift. These kites are quite difficult to fly, but do give the flier an exceptional opportunity to learn about how the angle of a kite in the wind affects its flight.
The popularity of dual control and quad line kites has had a marked influence on kites in general. Kites are more popular now than at any previous time in history. While the manoeuvrable kites have captured the imagination of many, there are also many people who have discovered the beauty and peacefulness of single line flying. The materials that have been used for manouevrable kites are now being used for single line kites as well, giving kite makers greater scope for creative endeavour. Their creations are becoming bigger and bigger, and the general public is taking more notice of them. During 1992 and 1993 there were two exhibitions of kites made by leading artists and kite makers touring the world, and kite festivals around the world are multiplying at an astonishing rate. As a sport, or a hobby, kites have much in their favour. They are cheap, quite easy to make, and most importantly, kites can teach the maker much about the physical world.