In the 1940s and 1950s the sound barrier took on an almost mythical status as engineers worldwide tried to build aircraft that could exceed the 1236 kilometres per hour (768 miles per hour) at which sound travels in air at twenty degrees Celsius.

In the 1940s
and 1950s the sound barrier took on an almost mythical status as engineers worldwide tried to build aircraft that could exceed the 1236 kilometres per
hour (768 miles per hour) at which sound travels in air at twenty degrees Celsius.