SPEED OF SOUND
On the ground, sound travels at
a speed of 1225 kilometers an hour. The speed of sound in the air is
slower - pilots call it Mach 1. Twice the speed of sound is Mach 2. By
1940s, the fastest planes were almost flying at Mach 1. Then in 1947 a
Force research plane broke the sound barrier.
Pilots noticed that when planes
flew at supersonic speeds they met huge shock waves, which acted like a
barrier. The waves caused loud noises like thunder, called sonic booms.
planes also became dangerously hot, despite such problems, engineers
designing supersonic aircraft that could withstand these effects.
In the 1950s British and French
engineers worked separately on developing a supersonic airliner. Then
the British Aircraft Corporation and French Aerospatiale joined forces.
worked together with Rolls-Royce and SNECMA, who manufactured jet
The companies called the
they were developing Concorde, which means harmony between nations.
years work, the end product was a narrow, 100 seat aircraft with
wings and a nose section that could be lowered when taking off and
Two Concordes were built in
each of the two countries. The first took off at Toulouse, in France,
March 1969. Engineers and pilots spend 5000 flying hours testing the
making it the most tested aircraft in history. Concorde finally entered
in 1976 with British Airways and Air France. Today each airline has a
seven Concordes. Only 16 production models have ever been built with
at the development bases.
Concorde is 62.1 meters long,
with a wingspan of 25.5 meters. It cruises at a height of up to 18,300
at Mach 2 – faster than some rifle bullets. It mainly flies from
Paris to New York. Its New York to London record, set in 1990 is 2
hours and 54
minutes – less than three hours to cross the Atlantic Ocean. The
follow routes that allow their sonic booms to take place over the sea.
Although Concorde is technologically a modern
wonder it is not a great commercial success. Eventually the whole fleet
grounded. The planes now being developed are much larger and can fly
distances without having to refuel. They can carry more passengers and
and cause less noise pollution.