Childrens Illustrated Encyclopedia

ENGINES

188

JET ENGINE

The jet, or gas

turbine, engine now powers most high-speed aircraft.
The engine blasts a jet of hot, fast-moving air

backward out of its exhaust; this pushes the engine
forward. Fans at the front of the engine spin and

suck air into it, and squeeze it at high pressure into
several combustion chambers. There, flames of

burning kerosene heat the air, which expands and
rushes toward the exhaust. As the air streams out,

it spins a turbine, which drives the fans at the front
of the engine.

TURBOFAN ENGINE

A turbofan engine is a very efficient kind of gas
turbine engine. Some of the air flows through

a bypass duct around the main part of
the engine. This increases the amount

of air flowing through the engine,
giving it more thrust. The duct also

helps make the engine quieter.

Fast-spinning fans called

compressors increase

the pressure of the air

and push it into the

combustion chambers.

Burning kerosene fuel inside the

combustion chambers heats the

air and makes it expand violently.

STEAM ENGINE
The steam engine was developed
during the 18th century and greatly
changed people’s lives. It led
to the development of industry
and transportation. People
left the land to work in the
new factories that contained
steam-powered machines,
and steam railroads allowed
people to travel farther and
faster than ever before.

Steam and smoke
escape through a
valve and pour out
of the smokestack.

The movement of the piston

drives the wheels of the train.

Steam passes

through a pipe

to a cylinder.

The steam pushes a

piston back and forth

inside the cylinder.

Boiler burns wood or

coal, producing heat.

Hot air and smoke pass through pipes

that run through the water tank. The

heat turns the water into steam.

Large fan spins, sucking
Some of the air air into the engine.
that enters the
engine flows
through the
bypass duct.

JAMES WATT

The first engine was a simple

steam engine invented by

the Greek scientist Hero

in the 1st century ce, but

it was little more than a

toy. In 1712, the British

engineer Thomas

Newcomen built the first

real engine. It was a huge

steam engine used to pump

water out of mines. In 1769,

another British engineer, James

Watt (left), greatly improved the

steam engine. The unit of power,

the watt, is named after him.

Hot air and exhaust

gases rush out of the

engine, spinning the

turbine as they go.

FRANK WHITTLE

In 1928, English pilot and engineer

Frank Whittle (1907-1996) suggested the

idea of the jet engine. Whittle’s engine

powered an experimental aircraft for the

first time in 1941. However, the first jet-

powered flight was made during the 1930s

in Germany, where engineer Hans von

Ohain had developed his own jet engine.

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