The world entered the passenger jet age 70 years ago today when the Hatfield built de Havilland DH106 Comet took off from the town’s airfield for its maiden flight. The aeroplane revolutionised air travel. Here is the Comet’s story.
Driving into Hatfield off the A1(M) towards The Galleria there is a road sign proclaiming: 'Birthplace of the Jet Airliner'.
There's another on the side of the road as you enter The Ryde area of Hatfield from the direction of Mill Green, and, fittingly, one along Comet Way near Birchwood.
The aeroplane in question is the pioneering de Havilland DH106 Comet - the world's first purpose-built passenger jet.
Designed and built in Hatfield, the aircraft took its maiden flight from the town's aerodrome 70 years ago today.
On July 27, 1949 - just four years after the end of the Second World Two - the de Havilland Aircraft Company beat its American competitors Boeing, Douglas and Lockheed to the honour of putting a pressurised passenger jet airliner in the skies.
Not to be confused with the de Havilland DH88 Comet Racer, which won the 1934 England-Australia MacRobertson Air Race, the DH 106 Comet broke new ground in aviation circles.
READ MORE: Hatfield Comet Racer air display cancelled
It was a game changer. Holidaymakers think nothing of jumping on a Boeing or Airbus these days and jetting to the other side of the world.
In the years immediately after World War Two, this was a pipe dream.
However, aviation visionary Geoffrey de Havilland turned that dream into reality.
The world famous Hatfield factory had already developed jet fighters during the war, and Britain was a leader in jet-engine technology.
Taking expertise pioneered on aircraft such as de Havilland's iconic fighter-bomber the Mosquito, the Sea Hornet and the Vampire fighter, the company set its sights on creating a passenger jet airliner.
The result, the de Havilland DH 106 Comet, was a world-beating feat of British engineering - even though the project was later hit by tragedy, more of which later.
Ronald Eric Bishop, de Havilland's chief designer and the man behind the Mosquito 'Wooden Wonder', developed the innovative turbojet-powered Comet.
In documentary evidence given to aircraft crash investigators, R. E. Bishop stated that at the end of the war de Havillands were faced with the problem of recommencing the manufacture of civil aircraft.
A Ministry of Transport and Civil Aviation accident report into two of the Comet's fatal 1954 crashes states: "During the war they had been building only military aircraft.
"They [de Havillands] decided that it would be inadvisable merely to build another version of the conventional aircraft; they had had some years' experience with jet fighters and concluded that with the help of their engine company they should be able to produce a useful civil aircraft which would be a step ahead of the current type."
With this in mind, design work started in September 1946 on the Comet.
The 1955 Ministry of Transport and Civil Aviation accident report adds: "Some idea, however, of the amount of work involved is indicated by the fact that it was not until the 27th July, 1949, that the first prototype Comet made its first flight."
Powered by four de Havilland Ghost 50 Mk1 engines, the Comet finally took to the skies for the first time in 1949, much to the surprise of the firm's American rivals.
As the silver Comet 1 prototype, registered G-ALVG, taxied down the Hatfield airfield runway, the plane heralded the dawn of a new era in passenger travel.
At the controls of the world's first commercial jet-powered airliner was de Havilland chief test pilot John Cunningham, aka 'Cat's Eyes' Cunningham.
The date of the flight - July 27 - was also significant as it was Geoffrey de Havilland's 67th birthday.
Pilot Cunningham was also celebrating his birthday.
Able to fly at high speed with a cruise altitude of up to 40,000ft, it revolutionised jet travel.
The Comet's beautifully sleek design, with its swept wings mounted below the pressure cabin, and its engines buried in the wing roots, gave it a distinctive look.
After a comprehensive flight development programme, British Overseas Airways Corporation took delivery of the first Comet in 1951.
Following further extensive testing, a BOAC Comet 1 entered scheduled service on May 2, 1952, with fee-paying passengers flying from London Heathrow Airport to Johannesburg in South Africa.
Six years later, on October 4, 1958, BOAC operated the first transatlantic jet passenger service between London and New York in a redesigned Comet 4 - beating Pan Am to the prize by a few weeks.
However, in between those two landmark flights, the Comet suffered a series of fatal crashes, before it was discovered that the fuselage fatigue life was far shorter than testing had predicted in the airframe.
In a severe tropical storm, BOAC Flight 783 departed Calcutta, India, for Delhi on May 2, 1953.
Six minutes after take-off, the plane - with 43 passengers and crew members - experienced an in-flight break-up and crashed, killing all on board.
On January 10, 1954, a BOAC Comet 1 departed Ciampino Airport, Rome, en route to London but plunged into the Mediterranean Sea near the island of Elba, killing all 35 passengers and crew.
After being temporarily taken out of service, the Comet was back in operation in March that year.
However, tragedy struck again on April 8, 1954 when a South African Airways Comet flying from Rome en route to Cairo, Egypt, crashed into the sea south of Naples, killing all 21 passengers and crew.
With the crash reminiscent of the Elba accident, the Comet's Certificate of Airworthiness was withdrawn and the fleet was grounded indefinitely while the British Government launched an unprecedented probe into the plane's safety record.
The aircraft crash investigation discovered metal fatigue caused by the repeated pressurisation and de-pressurisation of the aircraft cabin.
Extensive water tank testing of the fuselage at Farnborough revealed the areas affected by metal fatigue were located around the weakest points on the airframe which were subject to the most stress - the escape hatch cut out and corners of the passenger windows.
The Comet's punch rivet construction technique exacerbated its structural flaws.
The far-reaching Comet investigation paved the way for greater airline safety.
Rival manufacturers capitalised on de Havilland's misfortune, but without the Comet, we wouldn't have today's relatively safe air travel.
In 1955, de Havilland started taking orders for the Comet 4, with a redesigned fuselage and the original square windows now replaced.
You can see a surviving Comet 4 at IWM Duxford, while the de Havilland Aircraft Museum at Salisbury Hall, London Colney, has a Comet 1A fuselage with square windows.
While the de Havilland factory is no more - it's currently a housing estate, business park, university campus and a country park - there are still plenty of reminders of Hatfield's proud aviation history about town if you look.
The University of Hertfordshire's newest campus is named after de Havilland.
Comet Way runs through the middle of the town near the former factory site opposite The Galleria.
There are roads named after iconic de Havilland aircraft such as the Mosquito, Tiger Moth and Gipsy Moth.
Street names and places also commemorate some of the key figures involved in the town's aeronautical heritage, such as test pilot John Cunningham (Cunningham Avenue), Ronald Bishop (Bishops Square) and aerodynamics engineer Richard Clarkson (Clarkson Court).
And, referring back to the DH106 Comet, the David Lloyd Hatfield gym is housed in what was the Comet Flight Test Hanger and Control Tower.
Like the aircraft, this building was ahead of its time.
Developing the Comet required a huge new hangar to test and maintain it.
Built in just 13 weeks between 1952 and 1953, it was the largest aluminium building with an unsupported span in the world at the time of its construction.
The hangar and control tower measured 200 by 330 feet, and its doors had a clearance of 45 feet.
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