The three great British postwar airliners come alive in this the third edition of the Legends of the Air series. One was a pioneer in jet air transport that paid the price of discovering a previously relatively unknown problem in airframe design - fatigue. One was a major commercial success by any standard and a leader in its field. The third was an incomparable technological success that did not find its anticipated world market for a wide variety of reasons.
But for the little appreciated effects of metal fatigue associated with the new art of pressurisation, de Havilland's Comet would have secured the destiny of the British aircraft industry for decades to come, so advanced was it compared with the competition.
Meanwhile, the Viscount had no such problems, some 444 were built and the type even met with success in the fiercely contested North American market..
The Anglo French Concorde, the 'Big Racer', is elegance personified in an airframe designed in the pre digital age and yet after more than two decades of ultra safe day to day supersonic service is now set to fly on till at least 2010.
Viscount, Comet & Concorde features around 70,000 words of text, hundreds of photographs, 48 specifically commissioned color sideview drawings, technical drawings, specification and production tables, and more.
Excerpted from Viscount, Comet & Concorde (Legends of the Air, 3) by Stewart Wilson. Copyright © 1996. Reprinted by permission. All rights reserved
Intensive Investigation
A Court of Inquiry was established by the British Minister of Transport and Civil Aviation to report on the findings of the investigations into the Comet crashes, concentrating on the Elba (G-ALYP) and Naples (G-ALYY) accidents.
The Comet's structural integrity was the obvious centre of attention and two key activities were used to shed some light on this: the RAE's water tank which contained the fuselage of Comet 1 G-ALYU, and the remains of the Elba Comet, which was being 'reconstructed' at Farnborough over a period of several months as parts were gradually recovered. In addition, Comet 1A G-ANAV (the surviving Canadian Pacific aircraft which had been allocated to BOAC) was test flown to check that uncontrolled flutter of some part of the airframe had not contributed to the accidents.
The water tank test specimen at Farnborough provided the breakthrough in July 1954 when the structure failed after 1,830 simulated 'flights' had been made, these in addition to the 1,239 real flights the aircraft had logged prior to its grounding. De Havilland's engineers were mortified by this as the failure occurred well before the company's own estimates of a 'safe' life, remembering that over 16,000 'flights' had been simulated during the Comet's early structural testing.
It was later realised that de Havilland's testing methods had been fatally flawed due to a lack of knowledge. The test cabins had been pressurised to more than twice their normal level in order to impose greater stresses and - or so it was thought - to provide a healthy safety margin. The effect was the opposite as the higher pressure tended to bed down component parts, change the molecular structure of the metal and actually make it more resistant to fatigue failure! Nothing was known of this phenomenon at the time.
Examination of the test fuselage in the Farnborough water tank revealed the initial failure had occurred at a rivet hole in the corner of one of the square cabin windows and spread, creating a tear in the cabin skin eight feet (2.4m) long. Hairline fatigue cracks were also found starting in the rivet holes for the square ADF antenna cutout on the top of the fuselage.
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