In 2003, the world will celebrate the 100th anniversary of the
first flight of a piloted, controlled,
self-propelled, heavier than air craft;
the flight of the first airplane by the Wright brothers. While much
attention will be paid to the events of December 17,1903, at Kitty
Hawk, North Carolina, it is important to note that the flights of
that day were only the culmination of nearly five years of work by
the brothers. On this slide, we show computer drawings of the
aircraft which they used leading up to the 1903
flyer. All of the above aircraft are shown at the same scale.
The process which lead to the first successful airplane is the
same process used by engineers today to solve problems. The brothers
first performed a literature search to find out the state of
aeronautical knowledge at their time. They read about the works of
Cayley, and Langley, and the hang-gliding flights of Otto Lilienthal.
They corresponded with Octave Chanute concerning some of their ideas.
They recognized that control of the flying aircraft would be
the most crucial and hardest problem to solve. From the observation
of soaring birds, they believed that they could obtain roll
control by warping, or changing the shape, of
a portion of the wing.
In
1900
they built an aircraft
to test their theories. The aircraft had a 17 foot
wing span, a five foot chord, and a forward stabilizer, called a
canard, and weighed about fifty pounds without the pilot. For most of its
flights this aircraft was flown as a kite. Kitty
Hawk was chosen as the test site because of its sand dunes and constant
strong winds coming in from the sea. On the last day of the season, the
aircraft was flown as a
piloted glider and demonstrated roll
control through wing warping.
In
1901,
the brothers returned to Kitty Hawk with a new aircraft
which they had built at their bicycle shop in Dayton, Ohio. Their new
aircraft had the same basic design as the 1900 aircraft, but was
larger to provide more lift to carry a pilot in lighter
winds. It had a 22 foot wing span, a seven foot chord, a variable
elevator canard for pitch control, and
weighed about a hundred pounds without the pilot. The aircraft was
flown frequently up to 300 feet in a single glide. But the aircraft
did not perform as well as the brothers had originally expected. The
aircraft only developed 2/3 of the lift which was predicted by the
Lilienthal data. The drag was greater than predicted and the wing
would stall at a lower speed than predicted. The brothers modified
the curvature of the wing but this only slightly improved the flying
characteristics. During their test flights the brothers also
encountered an effect known as adverse yaw. On some flights,
when the wings were warped to produce a roll
which should result in a curving flight path in the direction of the
lower wing, the drag increased on the upper wing and the aircraft
would twist in the opposite direction. The air speed decreased and
the plane settled back to the ground. At the end of 1901, the
brothers were frustrated and Wilbur remarked that it would be a
thousand years before humans would learn to fly.
During the winter of 1901, the brothers began to question the
aerodynamic data on which they were basing their designs. They built
their own wind tunnel , the first tunnel
built in the United States, and began to test their own models. They
tested over two hundred different wings and airfoil sections in
different combinations to improve the performance of their gliders
They found that the previous data was in error and that their own
data more correctly described the flight characteristics which they
observed with their gliders.
In
1902,
they returned to Kitty Hawk with a new aircraft
based on their new data. This aircraft was even larger than the 1901
aircraft; it had a 32 foot wing span, a five foot chord, the canard
elevator, a new movable rudder at the rear, and it weighed about a
hundred and fifteen pounds without the pilot. The rudder was
installed to overcome the adverse yaw problem. The movable rudder was
coordinated with the wing warping to keep the nose of the aircraft
pointed into the curved flight path. With this new aircraft, the
brothers completed flights of over 650 feet. This machine was the
first aircraft that had active controls for all three axis; roll,
pitch and yaw. At the end of 1902, all that
remained for the first successful airplane was the development of the
propulsion system.
The Wrights could not find a manufacturer who would meet their
requirements for both lightweight and horsepower in an engine, so, in
a period of just six weeks, they built their own 12 horsepower
engine. They also created the first working aircraft propellers,
realizing that they must be shaped as a rotating airfoil.
In September of
1903,
they returned to Kitty Hawk with their new powered aircraft.
The aircraft was similar to the 1902 craft but with a longer 40 foot wing span,
a six foot chord, five feet between the wings and twin rudders and canard elevators
The plane also carried twin counter-rotating pusher propellers connected by bicycle chains
to the 12 horsepower motor. The pilot would lie beside on the motor on the lower wing.
With the pilot and the motor, the 1903 aircraft weighed a little over seven hundred
pounds. After a number
of frustrating problems with the propeller shafts and transmission
sprockets, they finally made four successful flights on December 17.
These ranged from a little over 100 feet to over 800 feet. After
almost 5 years of solving a myriad of problems, Wilbur and Orville
Wright had conquered powered flight.
Navigation..
- Re-Living the Wright Way
- Beginner's Guide to Aeronautics
- NASA Home Page
- http://www.nasa.gov
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