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. Archaeologists 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. 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. 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 a
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 breechers 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 upward 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 f lew
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
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 the Australian 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 anti-aircraft 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 19th and the beginning
of the 20th century, kites are now starting to imitate the
form of the aeroplane.
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. |