- McCullough, David.
The Wright Brothers.
New York: Simon & Schuster, 2015.
ISBN 978-1-4767-2874-2.
-
On December 8th, 1903, all was in readiness. The aircraft was
perched on its launching catapult, the brave airman at the controls.
The powerful internal combustion engine roared to life. At 16:45
the catapult hurled the craft into the air. It rose straight up,
flipped, and with its wings coming apart, plunged into the Potomac
river just 20 feet from the launching point. The pilot was
initially trapped beneath the wreckage but managed to free
himself and swim to the surface. After being rescued from the
river, he emitted what one witness described as “the most
voluble series of blasphemies” he had ever heard.
So ended the last flight of
Samuel
Langley's
“Aerodrome”.
Langley was a distinguished scientist and secretary of the
Smithsonian Institution in Washington D.C. Funded by the U.S. Army
and the Smithsonian for a total of US$ 70,000 (equivalent to
around 1.7 million present-day dollars), the Aerodrome crashed
immediately on both of its test flights, and was the subject of
much mockery in the press.
Just nine days later, on December 17th, two brothers,
sons of a churchman, with no education beyond high school, and proprietors of
a bicycle shop in Dayton, Ohio, readied their own machine
for flight near Kitty Hawk, on the windswept sandy hills of
North Carolina's Outer Banks. Their craft, called just the
Flyer,
took to the air with Orville Wright at
the controls. With the 12 horsepower engine driving the twin
propellers and brother Wilbur running alongside to stabilise the
machine as it moved down the launching rail into the wind, Orville lifted
the machine into the air and achieved the first manned
heavier-than-air powered flight, demonstrating the
Flyer was controllable in all three axes. The
flight lasted just 12 seconds and covered a distance of 120
feet.
After the first flight, the brothers took turns flying the machine
three more times on the 17th. On the final flight Wilbur flew
a distance of 852 feet in a flight of 59 seconds (a strong headwind
was blowing, and this flight was over half a mile through the air).
After completion of the fourth flight, while being prepared to fly
again, a gust of wind caught the machine and dragged it, along
with assistant John T. Daniels, down the beach toward the ocean.
Daniels escaped, but the Flyer was damaged beyond
repair and never flew again. (The Flyer which can
seen in the Smithsonian's National Air and Space Museum today
has been extensively restored.)
Orville sent a telegram to his father in Dayton announcing the
success, and the brothers packed up the remains of the aircraft
to be shipped back to their shop. The 1903 season was at an end.
The entire budget for the project between 1900 through the successful
first flights was less than US$ 1000 (24,000 dollars today), and was
funded entirely by profits from the brothers' bicycle business.
How did two brothers with no formal education in aerodynamics
or engineering succeed on a shoestring budget while Langley,
with public funds at his disposal and the resources of a
major scientific institution fail so embarrassingly? Ultimately
it was because the Wright brothers identified the key problem of
flight and patiently worked on solving it through a series of
experiments. Perhaps it was because they were in the bicycle
business. (Although they are often identified as proprietors of
a “bicycle shop”, they also manufactured their own
bicycles and had acquired the machine tools, skills, and
co-workers for the business, later applied to
building the flying machine.)
The Wrights believed the essential problem of heavier than air
flight was control. The details of how a bicycle is
built don't matter much: you still have to learn to ride it.
And the problem of control in free flight is much more
difficult than riding a bicycle, where the only controls
are the handlebars and, to a lesser extent, shifting the
rider's weight. In flight, an airplane must be controlled
in three axes: pitch (up and down), yaw (left and right), and
roll (wings' angle to the horizon). The means for control in each
of these axes must be provided, and what's more, just as for a
child learning to ride a bike, the would-be aeronaut must master
the skill of using these controls to maintain his balance in
the air.
Through a patient program of subscale experimentation, first
with kites controlled by from the ground by lines
manipulated by the operators, then gliders flown by a pilot
on board, the Wrights developed their system of pitch
control by a front-mounted elevator, yaw by a rudder at
the rear, and roll by warping the wings of the
craft. Further, they needed to learn how to fly using these
controls and verify that the resulting plane would be stable
enough that a person could master the skill of flying it.
With powerless kites and gliders, this required a strong,
consistent wind. After inquiries to the U.S. Weather Bureau,
the brothers selected the Kitty Hawk site on the North
Carolina coast. Just getting there was an adventure, but the
wind was as promised and the sand and lack of large
vegetation was ideal for their gliding experiments. They
were definitely “roughing it” at this remote
site, and at times were afflicted by clouds of mosquitos of
Biblical plague proportions, but starting in 1900 they
tested a series of successively larger gliders and by
1902 had a design which provided three axis control, stability,
and the controls for a pilot on board. In the 1902 season
they made more than 700 flights and were satisfied the
control problem had been mastered.
Now all that remained was to add an engine and propellers
to the successful glider design, again scaling it up to accommodate
the added weight. In 1903, you couldn't just go down to the
hardware store and buy an engine, and automobile engines were
much too heavy, so the Wrights' resourceful mechanic, Charlie
Taylor, designed and built the four cylinder motor from
scratch, using the new-fangled material aluminium for the
engine block. The finished engine weighed just 152 pounds
and produced 12 horsepower. The brothers could find no references
for the design of air propellers and argued intensely over
the topic, but eventually concluded they'd just have to make
a best guess and test it on the real machine.
The Flyer worked the on the second attempt (an earlier
try on December 14th ended in a minor crash when Wilbur
over-controlled at the moment of take-off). But this stunning
success was the product of years of incremental refinement of
the design, practical testing, and mastery of airmanship through
experience.
Those four flights in December of 1903 are now considered one of
the epochal events of the twentieth century, but at the time
they received little notice. Only a few accounts of the flights
appeared in the press, and some of them were garbled and/or
sensationalised. The Wrights knew that the Flyer
(whose wreckage was now in storage crates at Dayton), while a
successful proof of concept and the basis for a patent filing,
was not a practical flying machine. It could only take off
into the strong wind at Kitty Hawk and had not yet demonstrated
long-term controlled flight including aerial maneuvers such as
turns or flying around a closed course. It was just too difficult
travelling to Kitty Hawk, and the facilities of their camp there
didn't permit rapid modification of the machines based upon
experimentation.
They arranged to use an 84 acre cow pasture called Huffman
Prairie located eight miles from Dayton along an interurban
trolley line which made it easy to reach. The field's owner
let them use it without charge as long as they didn't
disturb the livestock. The Wrights devised a catapult to
launch their planes, powered by a heavy falling weight, which
would allow them to take off in still air. It was here, in
1904, that they refined the design into a practical flying
machine and fully mastered the art of flying it over the
course of about fifty test flights. Still, there was little
note of their work in the press, and the first detailed
account was published in the January 1905 edition of
Gleanings in Bee Culture. Amos Root, the
author of the article and publisher of the magazine, sent
a copy to Scientific American, saying they could
republish it without fee. The editors declined, and a year
later mocked the achievements of the Wright brothers.
For those accustomed to the pace of technological development
more than a century later, the leisurely pace of progress in
aviation and lack of public interest in the achievement of
what had been a dream of humanity since antiquity seems
odd. Indeed, the Wrights, who had continued to refine their
designs, would not become celebrities nor would their
achievements be widely acknowledged until a series of demonstrations
Wilbur would perform at Le Mans in France in the summer of
1908. Le Figaro wrote, “It was not merely
a success, but a triumph…a decisive victory for
aviation, the news of which will revolutionize scientific
circles throughout the world.” And it did: stories
of Wilbur's exploits were picked up by the press on the
Continent, in Britain, and, belatedly, by papers in the U.S.
Huge crowds came out to see the flights, and the intrepid
American aviator's name was on every tongue.
Meanwhile, Orville was preparing for a series of demonstration
flights for the U.S. Army at Fort Myer, Virginia. The army
had agreed to buy a machine if it passed a series of tests.
Orville's flights also began to draw large crowds from nearby
Washington and extensive press coverage. All doubts about
what the Wrights had wrought were now gone. During a
demonstration flight on September 17, 1908, a propeller
broke in flight. Orville tried to recover, but the machine
plunged to the ground from an altitude of 75 feet, severely
injuring him and killing his passenger, Lieutenant Thomas
Selfridge, who became the first person to die in an airplane
crash. Orville's recuperation would be long and difficult,
aided by his sister, Katharine.
In early 1909, Orville and Katharine would join Wilbur in France,
where he was to do even more spectacular demonstrations in the
south of the country, training pilots for the airplanes he was
selling to the French. Upon their return to the U.S., the Wrights
were awarded medals by President Taft at the White House. They
were feted as returning heroes in a two day celebration in Dayton.
The diligent Wrights continued their work in the shop between events.
The brothers would return to Fort Myer, the scene of the crash,
and complete their demonstrations for the army, securing the
contract for the sale of an airplane for US$ 30,000. The Wrights
would continue to develop their company, defend their growing
portfolio of patents against competitors, and innovate. Wilbur
was to die of typhoid fever in 1912, aged only 45 years. Orville
sold his interest in the Wright Company in 1915 and, in his retirement,
served for 28 years on the National Advisory Committee for
Aeronautics, the precursor of NASA. He died in 1948. Neither
brother ever married.
This book is a superb evocation of the life and times of the
Wrights and their part in creating, developing, promoting, and
commercialising one of the key technologies of the modern world.
- Carlson, W. Bernard.
Tesla: Inventor of the Electrical Age.
Princeton: Princeton University Press, 2013.
ISBN 978-0-691-16561-5.
-
Nicola Tesla was born in 1858 in a village in what is now Croatia,
then part of the Austro-Hungarian Empire. His father and
grandfather were both priests in the Orthodox church. The family
was of Serbian descent, but had lived in Croatia since the 1690s
among a community of other Serbs. His parents wanted him to
enter the priesthood and enrolled him in school to that end. He excelled in
mathematics and, building on a boyhood fascination with machines
and tinkering, wanted to pursue a career in engineering. After
completing high school, Tesla returned to his village where he
contracted cholera and was near death. His father promised him
that if he survived, he would “go to the best technical
institution in the world.” After nine months of illness,
Tesla recovered and, in 1875 entered the Joanneum Polytechnic
School in Graz, Austria.
Tesla's university career started out brilliantly, but he came
into conflict with one of his physics professors over the
feasibility of designing a motor which would operate without
the troublesome and unreliable commutator and brushes of
existing motors. He became addicted to
gambling, lost his scholarship, and dropped out in his third
year. He worked as a draftsman, taught in his old high school,
and eventually ended up in Prague, intending to continue his
study of engineering at the Karl-Ferdinand University. He
took a variety of courses, but eventually his uncles withdrew
their financial support.
Tesla then moved to Budapest, where he found employment as
chief electrician at the Budapest Telephone Exchange. He
quickly distinguished himself as a problem solver and innovator and,
before long, came to the attention of the Continental Edison Company
of France, which had designed the equipment used in Budapest. He
was offered and accepted a job at their headquarters in
Ivry, France. Most of Edison's employees had practical, hands-on
experience with electrical equipment, but lacked Tesla's
formal education in mathematics and physics. Before long, Tesla
was designing dynamos for lighting plants and earning a
handsome salary. With his language skills (by that time, Tesla
was fluent in Serbian, German, and French, and was improving his
English), the Edison company sent him into the field as a
trouble-shooter. This further increased his reputation and,
in 1884 he was offered a job at Edison headquarters in New York.
He arrived and, years later, described the formalities of
entering the U.S. as an immigrant: a clerk saying “Kiss
the Bible. Twenty cents!”.
Tesla had never abandoned the idea of a brushless motor. Almost
all electric lighting systems in the 1880s used
direct current (DC):
electrons flowed in only one direction through the distribution
wires. This is the kind of current produced by batteries,
and the first electrical generators (dynamos) produced direct
current by means of a device called a
commutator.
As the generator is turned by its power source (for example, a steam
engine or water wheel), power is extracted from the rotating commutator
by fixed brushes which press against it. The contacts on the
commutator are wired to the coils in the generator in such a way
that a constant direct current is maintained. When direct current
is used to drive a motor, the motor must also contain a commutator
which converts the direct current into a reversing flow to maintain
the motor in rotary motion.
Commutators, with brushes rubbing against them, are inefficient
and unreliable. Brushes wear and must eventually be replaced, and
as the commutator rotates and the brushes make and break contact,
sparks may be produced which waste energy and degrade the
contacts. Further, direct current has a major disadvantage
for long-distance power transmission. There was, at the time,
no way to efficiently change the voltage of direct current. This
meant that the circuit from the generator to the user of the
power had to run at the same voltage the user received,
say 120 volts. But at such a voltage, resistance losses in
copper wires are such that over long runs most of the energy
would be lost in the wires, not delivered to customers. You can
increase the size of the distribution wires to reduce losses, but
before long this becomes impractical due to the cost of copper
it would require. As a consequence, Edison
electric lighting systems installed in the 19th century had
many small powerhouses, each supplying a local set of
customers.
Alternating
current (AC) solves the problem of power distribution. In 1881
the electrical transformer had been invented, and by 1884
high-efficiency transformers were being manufactured in Europe.
Powered by alternating current (they don't work with DC),
a transformer efficiently converts current from one voltage and current to
another. For example, power might be transmitted from the generating
station to the customer at 12000 volts and 1 ampere, then stepped
down to 120 volts and 100 amperes by a transformer at the customer
location. Losses in a wire are purely a function of current, not
voltage, so for a given level of transmission loss, the cables
to distribute power at 12000 volts will cost a hundredth as
much as if 120 volts were used. For electric lighting,
alternating current works just as well as direct current (as
long as the frequency of the alternating current is sufficiently
high that lamps do not flicker). But electricity was increasingly
used to power motors, replacing steam power in factories. All
existing practical motors ran on DC, so this was seen as an
advantage to Edison's system.
Tesla worked only six months for Edison. After developing an
arc lighting system only to have Edison put it on the shelf
after acquiring the rights to a system developed by another
company, he quit in disgust. He then continued to work on
an arc light system in New Jersey, but the company to which
he had licensed his patents failed, leaving him only with a
worthless stock certificate. To support himself, Tesla worked
repairing electrical equipment and even digging ditches, where
one of his foremen introduced him to Alfred S. Brown, who
had made his career in telegraphy. Tesla showed Brown one
of his patents, for a “thermomagnetic motor”, and
Brown contacted Charles F. Peck, a lawyer who had made his
fortune in telegraphy. Together, Peck and Brown saw the
potential for the motor and other Tesla inventions and in
April 1887 founded the Tesla Electric Company, with its
laboratory in Manhattan's financial district.
Tesla immediately set to make his dream of a brushless AC motor a
practical reality and, by using multiple AC currents, out of phase with
one another (the
polyphase system),
he was able to create a magnetic field which itself
rotated. The rotating magnetic field induced a current in the
rotating part of the motor, which would start and turn
without any need for a commutator or brushes.
Tesla had invented what we now call the
induction motor.
He began to file patent applications for the motor and the
polyphase AC transmission system in the fall of 1887, and by
May of the following year had been granted a total of seven
patents on various aspects of the motor and polyphase current.
One disadvantage of the polyphase system and motor was that it required
multiple pairs of wires to transmit power from the generator to the
motor, which increased cost and complexity. Also,
existing AC lighting systems, which were beginning to come into use,
primarily in Europe, used a single phase and two wires. Tesla
invented the
split-phase motor,
which would run on a two wire, single phase circuit, and this was
quickly patented.
Unlike Edison, who had built an industrial empire based upon
his inventions, Tesla, Peck, and Brown had no interest in
founding a company to manufacture Tesla's motors. Instead,
they intended to shop around and license the patents to an
existing enterprise with the resources required to exploit
them. George Westinghouse had developed his inventions of
air brakes and signalling systems for railways into a
successful and growing company, and was beginning to compete
with Edison in the electric light industry, installing AC
systems. Westinghouse was a prime prospect to license the
patents, and in July 1888 a deal was concluded for cash,
notes, and a royalty for each horsepower of motors sold.
Tesla moved to Pittsburgh, where he spent a year working in
the Westinghouse research lab improving the motor designs.
While there, he filed an additional fifteen patent applications.
After leaving Westinghouse, Tesla took a trip to Europe
where he became fascinated with Heinrich Hertz's discovery
of electromagnetic waves. Produced by alternating current at
frequencies much higher than those used in electrical power
systems (Hertz used a spark gap to produce them), here was
a demonstration of transmission of electricity through
thin air—with no wires at all. This idea was to
inspire much of Tesla's work for the rest of his life.
By 1891, he had invented a resonant high frequency
transformer which we now call a
Tesla coil,
and before long was performing spectacular demonstrations
of artificial lightning, illuminating lamps at a distance
without wires, and demonstrating new kinds of electric lights
far more efficient than Edison's incandescent bulbs.
Tesla's reputation as an inventor was equalled by his
talent as a showman in presentations before scientific
societies and the public in both the U.S. and Europe.
Oddly, for someone with Tesla's academic and practical background,
there is no evidence that he mastered Maxwell's theory of
electromagnetism. He believed that the phenomena he observed
with the Tesla coil and other apparatus were not due to the
Hertzian waves predicted by Maxwell's equations, but rather
something he called “electrostatic thrusts”. He
was later to build a great edifice of mistaken theory on this
crackpot idea.
By 1892, plans were progressing to harness the hydroelectric
power of Niagara Falls. Transmission of this power
to customers was central to the project: around one
fifth of the American population lived within 400 miles
of the falls. Westinghouse bid Tesla's polyphase
system and with Tesla's help in persuading the committee
charged with evaluating proposals, was awarded the contract
in 1893. By November of 1896, power from Niagara reached
Buffalo, twenty miles away, and over the next decade extended
throughout New York. The success of the project made polyphase
power transmission the technology of choice for most
electrical distribution systems, and it remains so to this day.
In 1895, the New York Times wrote:
Even now, the world is more apt to think of him as a
producer of weird experimental effects than as a
practical and useful inventor. Not so the scientific
public or the business men. By the latter classes Tesla
is properly appreciated, honored, perhaps even envied. For
he has given to the world a complete solution of the problem
which has taxed the brains and occupied the time of the
greatest electro-scientists for the last two
decades—namely, the successful adaptation of electrical
power transmitted over long distances.
After the Niagara project, Tesla continued to invent, demonstrate his
work, and obtain patents. With the support of patrons such as
John Jacob Astor and J. P. Morgan he pursued his work on wireless
transmission of power at laboratories in Colorado Springs
and
Wardenclyffe
on Long Island. He continued to be featured in the popular press,
amplifying his public image as an eccentric genius and mad
scientist. Tesla lived until 1943, dying at the age of 86 of a
heart attack. Over his life, he obtained around 300 patents for
devices as varied as a new form of turbine, a radio controlled
boat, and a vertical takeoff and landing airplane. He speculated
about wireless worldwide distribution of news to personal mobile devices
and directed energy weapons to defeat the threat of bombers. While in
Colorado, he believed he had detected signals from extraterrestrial
beings. In his experiments with high voltage, he accidently detected
X-rays before Röntgen announced their discovery, but he didn't
understand what he had observed.
None of these inventions had any practical consequences. The
centrepiece of Tesla's post-Niagara work, the wireless transmission
of power, was based upon a flawed theory of how electricity
interacts with the Earth. Tesla believed that the Earth was filled
with electricity and that if he pumped electricity into it at one
point, a resonant receiver anywhere else on the Earth could extract
it, just as if you pump air into a soccer ball, it can be drained out
by a tap elsewhere on the ball. This is, of course, complete nonsense, as
his contemporaries working in the field knew, and said, at the
time. While Tesla continued to garner popular press coverage for
his increasingly bizarre theories, he was ignored by those who
understood they could never work. Undeterred, Tesla proceeded to
build an enormous prototype of his transmitter at Wardenclyffe,
intended to span the Atlantic, without ever, for example, constructing
a smaller-scale facility to verify his theories over a distance of,
say, ten miles.
Tesla's invention of polyphase current distribution and the
induction motor were central to the electrification of
nations and continue to be used today. His subsequent work
was increasingly unmoored from the growing theoretical understanding
of electromagnetism and many of his ideas could not have worked.
The turbine worked, but was uncompetitive with the fabrication
and materials of the time. The radio controlled boat was clever,
but was far from the magic bullet to defeat the threat of the
battleship he claimed it to be. The particle beam weapon (death
ray) was a fantasy.
In recent decades, Tesla has become a magnet for Internet-connected
crackpots, who have woven elaborate fantasies around his work.
Finally, in this book, written by a historian of engineering and
based upon original sources, we have an authoritative and unbiased
look at Tesla's life, his inventions, and their impact upon society.
You will understand not only what Tesla invented, but why, and how
the inventions worked. The flaky aspects of his life are here as
well, but never mocked; inventors have to think ahead of
accepted knowledge, and sometimes they will inevitably get things
wrong.