Ever since the Greek Mythology of Icarus and Daedalus, man has been on a great quest to discover the secret of
flight and when man finally managed to fly, this discovery was to change the
way he lived upon this Earth. Like the advent of the automobile, powered manned
flight was not a single invention but a gathering together of necessary
knowledge to allow flight to be possible. This knowledge began being collected
by the Chinese who flew kites for the first time somewhere around 500 BC.
The kite was an important step in achieving
powered manned flight because it showed that something heavier than air could
stay aloft. The kite may have been the invention of the Chinese philosophers Mozi and Lu Ban during the 5th Century BC. Although not fully
understood at the time, the kite showed the basic laws of aerodynamics at work.
Air flowing over a kite’s wing will have a high pressure below the wing and a
low pressure above the wing, giving the kite lift. This lift also produces drag
at the bottom of the kite opposite to the oncoming wind. When the kite is
tethered to a guide-wire the forces of the wind against the tension from the
guide-wire forces the kite into the air along a vector opposed to the tension
of the guide-wire and wind. Some kites have tails to stabilize the direction of
the kite adding the force of drag to the equation pulling on the tail, thus
keeping the kite stable and upright.
A box kite design provides relatively high
amounts of lift and most of the early aircraft of the Twentieth Century were
inspired by this design. The box kite was invented by the Australian inventor
Lawrence Hargrave in 1893 in his attempts to develop his own manned flying
machine. Series of tandem box kites were able to lift Hargrave 16 feet off the
In 1738 a Dutch-Swiss mathematician published
an important aerodynamic principal in his book Hydrodynamica, which stated that any air (or fluid) flow as speed
increases will result in a simultaneous decrease in pressure over a solid
surface, which became known as Bernoulli’s
principal. Air running over the top of an airfoil will run faster than the
air running under the bottom of the airfoil thus creating a decrease of
temperature and pressure which provides lift. The significance of this to
flight is that Bernoulli’s principal explains
the concept of lift and allows lift to be calculated on airfoils.
In 1799 Sir George Cayley was credited with
formally identifying the four aerodynamic forces acting upon flight – lift,
gravity, thrust and drag. Cayley believed that that any drag created by a
flying machine must be countered by thrust in order for level flight to occur,
which led to a better understanding that any design of a flying machine must
minimize drag. These discoveries led to the development of cambered wings,
which enabled them to create the force of lift for an aircraft. According to a
recent discovery of Cayley’s school notebooks, he pondered over the problems
like the angle of attack much earlier than previously thought in his early
Cayley designed an efficient cambered wing with the correct dihedral angle that
provided lateral stability in flight, where he deliberately set the centre of
gravity below the wings for that purpose.
Cayley’s model gliders incorporated all these features, monoplane wings with
back horizontal stabilizers, looking similar to modern aircraft of today. There
was possibly a glider built by Cayley in 1853 that was piloted by his grandson
George John Cayley.
The propeller has a long history of
development for nautical use which had to be applied to flight. One of the
major challenges to the Wright Brothers in developing an airplane for their
first flight at Kitty Hawk was that there was no aircraft propeller readily
developed, so had to develop one on their own. They found that a propeller is
essentially a wing and therefore they utilized early wind tunnel data on their
wing experiments. They found that the relative angle of attack of the propeller
had to be different along the propeller blade and therefore had to be twisted
The Wright brothers believed that the ability
to fly depended upon balance and control, rather than the power of an engine to
propel the airplane forward. This perhaps came from their background as bicycle
makers where balance was essential. Control in the air was an important issue
as there had been many deaths of aeronauts in gliding and balloon accidents
over a number of years.
The Wright brothers further believed they had
enough knowledge about wings and engines and decided it was important to
practice control in gliding before powered flight so the needs of control could
be understood. They believed that
previous practice used by Lilienthal of balancing and controlling a glider
through redistributing body weight was fatally flawed.
Many before them including Langley and Chanute considered changing direction in
midflight would be like moving a ship’s rudder for steering while the aircraft
remained in straight and level flight.
Wilbur Wright observed that birds change direction in flight by changing their
angle at the end of the wings to make their body’s roll to the left or right
and he thought that this would also be a good way for an aircraft to change
direction by banking left or right by changing the wing tilt through the use of
a moveable airfoil on the sides of the wing. Again this was something similar
to a bicycle going at high speed where a rider would distribute his or her
weight to the side of a turn.
In 1900 the Wright brothers after researching
the best place to do glide tests and taking advice from Octave Chanute went to
Kitty hawk, North Carolina. The area had a good breeze coming onshore from the
Atlantic, a soft sandy ground to land on, and was relatively remote for
privacy. The first glider was based more on the work of previous pioneers and
resembled the Chanute-Herring glider which flew well near Chicago back in 1896
and some aeronautical data that Lilienthal had published. The wings were
cambered according to the theories of Sir George Cayley. The Wrights placed a
horizontal elevator in front of the wings as they believed this would help them
stop any nose dives that killed Lilienthal
and did not build a tail for the glider as at this stage as they thought it
unnecessary. Most of the glider tests were unmanned with the glider held by
ropes so glide characteristics could be studied.
The second glider in 1901 had its wings
greatly enlarged in an attempt to increase lift. Approximately 100 flights were
made at varying distances from 50 to 400 feet. The glider stalled a number of
times but “pancaked” out and landed
flat due to the forward elevator. This changed the brothers thinking towards
the canard design, which they used until
1910. In general the second glider was very disappointing as it failed to yaw
adequately to the wing ailerons, where the nose of the glider pointed away from
the turn as the wings produced differential drag and didn’t have the lift that
they had expected. This left the Wright brothers feeling very down about the
prospects of manned flight.
The Wright brothers discovered that the
equation that Lilienthal had been using to calculate lift was incorrect.
Lilienthal and the Wright brothers both used the “Smeaton coefficient” in the lift equation which had a constant of
0.0054, overstating lift. The Wright brothers believed and determined through
some bicycle tests that the coefficient was more like 0.0033 and adjusted their
designing accordingly. Knowing that building gliders was expensive and trial
and error was very time consuming they built their own wind tunnel so they
could test models to speed up their experimentation and learning. These
experiments proved to be very fruitful and they made an important discovery
that longer and narrower wings (i.e.,
larger aspect ratio) would provide a better lift to drag ratio than broader
wings. They also reduced the camber of airfoils which made them more efficient
for banking. They totally discarded Lilienthal’s calculations and relied solely
on their own data.
The third glider had some other design changes
including a rear fixed vertical rudder which would assist in turning. The
brothers flew the third glider unmanned like the first two trials. The glider
gave the expected lift and allowed tighter turns without the amount of
differential wing drag that occurred on the earlier gliders. However the rudder
caused a new problem. When in a tight turn and trying to level back out again
the glider failed to respond to the airfoil corrections and persisted in a
tighter turn where the glider would slide towards the lower wing. The brothers
found that by making the rudder movable this problem did not reoccur so with a
movable rudder and wing airfoils the pilot had to control both the airfoils and
rudder when maneuvering the glider. This enabled the brothers to make very
The three-axis control for the glider was a
major breakthrough for controlled flight. It made the aircraft very
controllable in flight and was the result of almost 1,000 test glides at Kitty
Hawk. Some aeronautical historians believe that this is where the airplane was
The powered Wright Flyer I constructed of
spruce and covered with muslin. The engine was built with an aluminum block by
the brothers. The Wrights decided on twin pusher counter rotating propellers to
cancel out the torque. They suffered many delays at Kitty Hawk with broken
propeller shafts. After a number of attempts the brothers finally got the
airplane off the ground on 17th December 1903 with a flight distance
of 120 feet. The first flights received little publicity. Over the following
year the second aircraft the Wright Flyer II made many flights at Dayton with
many hard landings and minor mishaps. Much progress was made in 1904 with some
longer flights lasting a few minutes but the airplane was still very difficult
In 1905 the brothers made all the controls
independent of each other so pitch, roll, and yaw could be controlled
separately of each other. After a nearly fatal crash the brothers rebuilt the
flyer with a much larger rudder and forward elevator placed further away from
the wings. This made control much easier and led to a number of much longer
flights. Ironically the media had ignored this story that Wilbur and Orville
Wright made the first flights with a powered flying machine and later would
become national heroes at their own doorstep.
The brothers believed that they now had a
flying machine with practical utility that they could sell. They were finally
granted a patent in 1906 and in 1907 went to Europe to sell their airplane. In
early 1908 the Wright brothers finally signed contracts with a French company
and the US Army. Wilbur made a number of demonstration flights showing advanced
maneuvers during 1908 which captured the attention and admiration of the world.
The Wright brothers’ patent was challenged
vigorously in the law courts for a number of years and Wilbur Wright also
challenged any other flyer who infringed them. This took up a lot of time and
it prevented the brothers from developing new aircraft designs. By 1911 the
Wright airplanes were considered inferior to many of the new European designs.
Wilbur passed away in 1912 and the brothers won their court case against
Curtiss which had been going on for a few years. With the arrival of the First
World War, the US Government found that American technology was behind the
European builders and encouraged companies to cross license their technologies.
Businesswise the invention of the airplane did
not lead to a great number of aircraft sales and the brothers formed an
exhibition team which was later disbanded due to a number of team member
deaths. Between 1910 and 1916 the Wright Company operated a flying school at
Huffman Prairie, Dayton, training more than 100 pilots. In addition with the
large number of airplane accidents and deaths the safety of the plane came into
question by the US Army. Orville Wright sold the Wright Company in 1915 and
took on public service as an elder aviation statesman becoming director of the
National Advisory Committee for Aeronautics (NACA), which he served for 28
years. It was only after the First World War when airplanes made a contribution
to field warfare as a reconnaissance, fighter and bomber, and larger airplanes
could carry passengers and cargo with much better safety that the aviation
industry started to boom from the 1920s onwards.
So what are the lessons we learn from the
invention of the airplane?
What we see is that an invention cannot occur
until all relevant knowledge that makes it possible exists. There must be no
knowledge gap, or else any idea is a fantasy. For example, Jules Verne’s
imaginative novel From the Earth to the
Moon in 1865 could only become reality with the Apollo Moon landing in 1969
when all necessary technology actually existed.
However the inventor must go the final step
and either synthesize all previous knowledge or incrementally enhance what
knowledge already exists to complete the invention. This often requires having
the confidence to disregard previous generally accepted knowledge with your own
generated knowledge obtained through your trials and experimentation.
What we also see is that any invention that
does not fulfill the present needs of consumers or industry will not initially
be commercially viable. In the cases of the early automobiles and aircraft,
they were not at an advanced enough state for potential users to accept them
because of the primitive state of the invention and social situation
surrounding it, i.e., early automobiles
not practical due to faults and UK laws had to be amended to make the invention
acceptable an means of transport.
Inventions can only be commercially successful
is if a use is found for it, i.e., early
aircraft could be utilized in a war situation during the First World War. The
story of the development of the airplane shows how essential trial and error or
learning by doing is essential to the successful development of any invention.
Murray Hunteris associate professor at the University Malaysia Perlis, and consultant to Asian governments on community development and village biotechnology. Murray is the inventor/author of a number of chemistry patents in Australia and as a researcher was the first to report many new natural compounds in international journals like the prestigious Journal of Essential Oil Research.
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McClelland and Stewart.
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Orville Wright, New York, W.W. Norton & Company.
 Tobin, J. (2004). To Conquer the Air: The Wright Brothers and
the Great Race to Flight, New York, Simon & Schuster, P. 53.
 This was a very different attitude to other pioneers
at the time like Ader, Maxim, and Langley who believed that after attaching an
engine to an airframe they could just go out and fly it without any experience.
 Crouch, T.D. (2003). The Bishop’s Boys: A life of Wilbur and
Orville Wright, New York, W.W. Norton & Company.
 Tobin, J. (2004). “To Conquer the Air”
 Jakab, P. L. (1997). Visions of a Flying Machine: The Wright
Brothers and the process of invention, Washington, DC, Smithsonian.
 Canard is French for duck and in aeronautic refers to
a wing configuration where the forward wings have a smaller area than the back
wings, which adds to lift.
 Langewiesche, W. (1944). Stick and Rudder: An explanation of the art
of flying, New York, McGraw-Hill.
 Tobin, J. (2004). “To Conquer the Air”, P. 211.
 However the Wright Brothers themselves can be part of
the blame for this as they discouraged media attention in fear of competitors
stealing their ideas and they would not be able to get a patent.