We often take for granted how easily a plane weighting over
half a million pounds lifts off the ground with such ease. This miracle can be
accredited to jet engines- an invention that uses Newton’s third law of physics
to create ‘thrust’. Developed in 1930's by Hans von Ohain in Germany and Frank
Whittle in Britain, the modern jet engine represents the 80-years evolution of
the gas turbine-a kind of rotating device that extracts energy from a fluid
flow and converts it into energy.
Jet engines are a form of ‘air-breathing’ gas turbines in
which the fluid (air) is compressed. Mixed with fuel and burned at high
temperature and pressure to create a flow of hot gas that spins the turbine.
This jet of gas then streams out the back, creating a huge amount of thrust-
equivalent almost to the power of 1,500 cars, enabling the plane to take off
into air despite its heavy weight.
What’s interesting to note is that in the case of jet
engines, bigger is not always better. To measure the power of a jet engine, its
thrust –to- weight ratio is more important than its size. Fighter jets and
Turbo jets used for the fast warplanes and the supersonic Concorde therefore
had higher thrust-to-weight ratios to enable high-speed manoeuvres and
near-vertical climbs. However, through fast, these jet engines consume
bucket-loads of fuel and are therefore not appropriate for commercial airplanes
that need to maintain cruising speed while using fuel efficiently. It’s thanks
to the jet engine that today we’re able to travel distances at speeds that
would have been impossible 80 years ago. This invention truly changes the face
of aviation forever.
