High-pressure steam
All of Watt’s engines used low-pressure steam. He always refused
to make high-pressure engines because he was afraid of
explosions. The move into high-pressure steam was made at
about the same time by two men, Richard Trevithick in England
and Oliver Evans in the US. Evans had begun to work on his
high-pressure steam engine in 1773, at the age of eighteen. In
1789, he invented the first steam-powered land vehicle. It is
possible that Trevithick borrowed his ideas from Evans, but Evans
never said so, and it is more likely that he had the same ideas
independently.
Trevithick came from Cornwall, in the southwest of England,
and his most successful engine was called “the Cornish engine.”
He was also the first man to build a working railroad engine, in
1804. This could move at six kilometers an hour. His example was
followed by George Stephenson, who built one in 1815. Ten years
later, Stephensons engines ran at a record speed of twenty-five
kilometers an hour between Stockton and Darlington in the
north of England. This was the first railroad to carry passengers
on regular schedules. Stephensons engine, the Rocket, pulled
twenty-one passenger cars containing 450 passengers.
Steam was used to power boats and ships from the very
early days. The first steamboat traveled up the River Saone, in
France, in 1783. By the end of the nineteenth century, the world
depended on steamships for moving things from country to
country and for defense.
Although a number of steam-powered road vehicles had been
built during the nineteenth century, their great weight had meant
that they were mainly limited to farm work. At the end of the
nineteenth century, although steam was used to power trains,
ships, and factories, local travel still depended on the horse. In
foct, the number of horses in London at the time had become a
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great problem; hundreds of men worked to clean the streets that
they passed through.
Gasoline and jet engines
Human progress needed a new idea, and it appeared as the
gasoline engine. In a steam engine, a fire heated water to produce
power. In this new engine, the gasoline itself was lit inside the
tube. The French engineer Alphonse Beau de Rochas first had
the idea, in 1862. In Germany, Nikolaus Otto turned the idea
into a working engine. O tto sold around 35,000 of his engines in
the next ten years, and by that time other German engineers had
built better ones.
Gottlieb Daimler had worked in O tto’s factory from the early
1870s and had helped him with his new engine. In 1882, he left
and started his own company with Wilhelm Maybach, and in
three years they built a modern, lightweight gasoline engine. In
1885, Daimler produced the first motorcycle to test it, but Karl
Benz had built a gasoline-driven car by the same year. Daimler
and Maybach showed their car a year later. In 1892, Rudolf
Diesel invented a different kind of engine. This used a heavier
kind of oil, which lit under pressure. His idea was especially
useful for heavy ship or factory engines.
Frank W hittle joined the British air force at the age of sixteen.
He became a fighter pilot, a test pilot, and then spent 1934—37 at
Cambridge University studying mechanical sciences. He realized
the need for a very fast airplane which could use the thinner air
higher in the sky. By 1930, he had invented a jet engine. Like the
gasoline engine, this burned gasoline and air, but instead of using
the power to make a propeller turn, it sent the hot gas straight
out behind the airplane to push it forward.
The government didn’t seem interested in his idea, so Whittle
started a company, Power Jets Limited, in 1936. The first engine
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was ready for testing the following year. The beginning of the
Second World War changed the government’s attitude and
W hittle’s first jet airplane, the Gloster E28/39, flew in May 1941.
It reached a top speed of 600 kilometers an hour and a height of
7,500 meters.
In Germany, Hans Joachim Pabst von Ohain had built a jet
engine in 1935, but he received more government support and
had his first jet— the Heinkel He 178— in the skies earlier than
the British machine. On 19 July 1942, the Messerschmitt 262
took off. This was the world’s first jet-powered fighter. The first
British jet was used by the British air force in 1944.
Progress was slower in Germany because of engine problems
with the Messerschmitt 262. In the end, around 1,430 airplanes
were built, and they appeared in the skies over Germany in the
final months of the war. They were very fast but could only fly
for a short time, and they made no difference to the result of the
war. But the new knowledge in both countries was useful in the
following years. Since then, jet engines have been used to fly
people around the world in greater and greater numbers.
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