John Derry & the speed of sound

It was on Monday 6th September 1948 that John Derry became the first British pilot to exceed the speed of sound.

The de Havilland DH.110 Sea Vixen was designed during the late 1940s at its facility in de Havilland’s Hatfield site and was a carrier-based fleet defense fighter that served into the 1970s.  In September 1951, an initial prototype was completed and conducted its maiden flight from Hatfield Aerodrome, piloted by John Cunningham. Early flight tests demonstrated that the aircraft’s performance exceeded expectation and by the following year the prototype was regularly flying in excess of the speed of sound.

It was decided that on Saturday 6th September 1952 at the Farnborough Air Show pilot John Derry and observer Anthony ‘Tony’ Richards would demonstrate its capability.  Following a demonstration of its ability to break the sound barrier they brought the plane down to make a low level flight across the airfield.  As it crossed the watchers the aircraft disintegrated and debris landed in the midst of spectators killing 29 watchers and the crew of two – test pilot and record breaker John Derry and his partner Tony Richards.

Subsequent investigation of the accident traced the failure to faulty design of the end sections of the main spar, which resulted in the outer ends of the wings shearing off during a high-rate turn. The subsequent shift in the DH 110’s centre of lift caused the aircraft to lurch violently, creating forces of over 12g, resulting in the cockpit and tail sections breaking away and the engines being torn from the airframe. One of the engines hit an area crowded with spectators at the end of the runway, causing the majority of casualties. Other spectators were injured by debris from the cockpit landing close to the main spectator enclosures alongside the runway. The incident led to a restructuring of safety regulations for UK air shows in the UK, and no member of the public died as a result of a UK air show demonstration flight for more than 62 years.

It was on Saturday 22nd August 2015 that a Hawker Hunter crashed at the Shoreham Air Show with 11 deaths.

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