zoggavia

De Havilland Comet

History of the world's first Jetliner

Comet 1

G-ALVG Prototype at Farnborough 1951, Zoggavia Collection


Design work began in 1946 under Ronald Bishop and the intention was to have a commercial aircraft by 1952. The de Havilland DH 106 Comet 1 first flew on 27 July 1949 The dsign was similar to other airliners except that four of the new, albeit underpowered, de Havilland Ghost 50 turbojets  were mounted within the wings, in pairs close to the fuselage. The airliner underwent almost three years of tests and fixes and the first commercial flights did not begin until 22 January 1952 with Boac. The first passenger flight was in May from London Heathrow Airport to Johannesburg, South Africa.




G-ALYX seen at Bangkok 1953,  Zoggavia Collection

The
jet airliner proved to be around twice as fast as contemporary aircraft, like the Constellation, and with almost 30'000 passengers carried in the first year over fifty Comets were ordered.





F-BGSA Comet 1A  in Aeromaritime colors seen in North Africa, 1953, Zoggavia Collection



The first sign of a flaw in the Comet came on 2 May 1953 when a Comet 1 G-ALYV crashed in a severe tropical storm six minutes after taking off from Calcutta/Dum Dum, India killing all 43 on board.
Further crashes followed. On 10 January 1954, 20 minutes after taking off from Ciampino, Comet G-ALYP broke up in flight and crashed into the Mediterranean off the Italian island of Elba, with the loss of all 35 on board. There was no obvious reason for the crash, and the fleet was grounded while the Abell Committee met to determine potential causes of the crash. Then on 8 April 1954, Comet G-ALYY, on charter to South African Airways, was on a leg from Rome to Cairo (of a longer flight from London to Johannesburg), when it crashed in the waters near Neaples The fleet was immediately grounded once again and a large investigation board was formed under the direction of the Royal Aircraft Establishment (RAE). Royal Navy was tasked with helping to locate and retrieve the wreckage so that the cause of the accident could be found.
Engineers subjected an identical airframe, G-ALYU, to repeated re-pressurization and over-pressurization and after 3,057 flight cycles (1,221 actual and 1,836 simulated), YU failed due to metal fatigue near the front port-side escape hatch. Investigators began considering fatigue as the most likely cause of both accidents and initiated further research into measurable strain on the skin. It was found in February 1955 that, as suspected, metal fatigue was the problem; after thousands of pressurized climbs and descents, the thin fuselage metal around the Comet's distinctive right-angled, large windows would begin to crack and eventually cause sudden depressurization and catastrophic structural failure. 


Comet 2




G-AMXK Comet 2E in Boac colors on a proving flight in the USA,
1957, Clinton H. Groves Collection

All remaining Comets were either scrapped or modified and the program to produce a Comet 2 was put on hold. The Comet 2 had a slightly larger wing, higher fuel capacity and more powerful Rolls Royce Avon engines which all improved the aircraft's range and performance. Following the Comet 1 disasters, these models were rebuilt with heavier gauge skin and rounded openings. 12 of the 44-seat Comet 2s were ordered by BOAC for the South Atlantic route. The first production aircraft (G-AMXA) flew on 27 August 1953. Although these aircraft performed well on the South Atlantic routes, their range was still not suitable for the North Atlantic. All but four Comet 2s were allocated to the RAF.




XK695 Comet C2 in Royal Air Force markings during take off
at Malta 1967,  Zoggavia  Collection

Eight Comet C2 transport aircraft and two Comet T2 crew trainers were delivered to the RAF beginning in 1955.

Comet 3



G-ANLO Comet 3 prototype in Boac colors during the
Farnborough air show in 1957,  Zoggavia  Collection



The Comet 3 was a lengthened Comet 2 with greater capacity and range, which flew for the first time on 19 July 1954. It was demonstrated at the Farnborough SBAC Show in September. After the fatigue accidents, orders dwindled and only two Comet 3s were constructed. G-ANLO was the only flying Comet 3, and took part in a marathon round-the-world promotional tour in December 1955, flown by John Cunningham. It was modified with reduced span wings as the Comet 3B and was displayed at Farnborough in September 1958. The other Comet 3 was used for structural and technology testing during development of the similarly sized Comet 4.


Comet 4

The Comet 4 included many modifications compared to the original Comet 1. It used a strengthened fuselage and round windows to alleviate the metal fatigue problems of the Comet 1. The Comet 4 was also a considerably larger aircraft, 5,64 m (18 ft 6 in) longer than the Comet 1 and typically seating 74 to 81 passengers, compared to the Comet 1's 36 to 44. It also had a longer range, higher cruising speed, and higher maximum takeoff weight. These improvements were possible largely due to the use of Rolls-Royce Avon engines with over twice the thrust of the Comet 1's de Havilland Ghosts.

BOAC ordered 19 Comet 4s in March 1955 despite the Comet 1's problems. The Comet 4 first flew on April 27, 1958, and deliveries to BOAC began that September. BOAC initiated Comet 4 service with a flight from London to New York via Gander on 4 October 1958.



G-APDC Comet 4, departing to the return flight to London,
4 October 1958,  Zoggavia  Collection

That flight was the first scheduled trans-Atlantic passenger jet service, beating Pan American's inaugural 707 service by three weeks. Two other variants of the Comet 4 were developed. The Comet 4B included a stretched fuselage and shorter wings; it was targeted to the fairly short-range operations of British European Airways, which placed an initial order for it in 1958.


G-APMB first BEA Comet 4B, during a demonstration flight at the
Farnborough show 1959, Zoggavia  Collection


The Comet 4B first flew on 27 June 1959 and BEA inaugurated services with it in April 1960. The final Comet 4 variant was the Comet 4C, with the longer fuselage of the Comet 4B but the larger wings and fuel tanks of the original Comet 4, which gave it a longer range than the 4B.


SU-ALD Comet 4C, Misrair 1962  Zoggavia  Collection


It first flew on October 31, 1959, and Mexicana started Comet 4C services in 1960. In total, 76 Comet 4 family aircraft were delivered from 1958 to 1964. Although BOAC retired its Comet 4s from revenue service in 1965, other operators (of which Dan -Air was the largest and last) continued flying commercial passenger services with the aircraft until 1980.




G-BDIW Comet 4C spotting new Dan-Air London livery,
Stockholm Arlanda 1979,  Zoggavia  Collection


The last Comet flight was conducted in 1997 by a Comet 4C that had been owned by the British government.


XS235 Comet C4 A&AEE, Fairford, UK July 1994,  Zoggavia  Collection


Although the Comet was the first jetliner in service, the interruption of commercial service and the damage to the aircraft's reputation caused by the Comet 1 fatigue failures meant that the jetliner market was dominated by Boeing , which flew the first prototype 707 in 1954,  and Douglas , which launched the DC-8  program in 1955.  Only fifteen airlines ever used the Comet, the proposed Comet 5 was never built, and the Comet 4s were slowly withdrawn from service. A few additional aircraft were used by the military, but only the Nimrod, a Comet derivative.The Nimrod is a highly capable maritime reconnaissance platform that served with distinction in the Falkland Islands War with Argentina.




XV252 MR.2, later converted to AEW.3, seen at
Waddington, UK September 1994,  Peter R. Foster Collection



The airframe is based on that of the de havilland Comet jetliner but with new engines and an enlarged lower fuselage containing a weapons bay.




XV285 AEW.3, on duty 1985,  Chris Knott Collection

The most recent model is the MRA.4 equipped with much more capable radar, faster computers, and other avionics.

Summary and technical data
   Comet Series
1
1A
2
 3  4 4B
 4C
Dimensions
Length (m)
28,61 28,61 29,53 33,98 33,98 35,97 35,97
   Wingspan (m)
34,98
 34,98 34,98 
34,98 
34,98  32,87  34,98
   Height (m)
 8,99 8,99
 8,99
8,99
8,99
8,99
8,99
  Wing Area (m2)
 188,3 188,3
188,3
197,04
197,04
191,30
197,04
Weight
Take off (t)
47,6
 52,2 54,4
 65,8 73,4
71,6
73,5
  Fuel capacity (l)
 27'300 31'395
31'395
38'000
40'450
35'460
 40'450
  Max Payload (t)
 5,7 5,4
 6,1 9,2
 9,2  10,9 10,9
 Propulsion Powerplant
 Ghost
50 Mk
1
 Ghost
50 Mk 1

 Avon
 Mk 117
Avon
502
Avon
524

Avon
 524

Avon
 525B

  Thrust (KN)
89,2
 89,2  130  178 187
 187 187
 Performance  Speed (km)
 725  725 770
 805  805
850
 805
  Range (km)
 2415  2850 4065
 4395  5190 4025
 6900
   Passengers 36
44
44
 58-71  56-109 71-119
79-119
 First Flight
 Date 27.7.1949
 11.8.1952 27.8.1953
 19.7.1954  27.4.1958  27.6.1959 31.10.1959
 First Service
Date
2.5.1952
      4.10.58
 1.4.1960  1960
Operators

Aerolineas Argentinas
Air France
Air India
Boac
BEA
Channel Airways
Dan-Air London
Dick Drost
East African Airways
Ghana Airways
Kuwait Airways
Malaysian Airways
Malaysia Singapore
Mexicana
Middle East Airlines
Misrair
Olympic Airways
Qantas
Sudan Airways
Union Aeromaritime de Transport
United Arab Airlines / Egyptair

Military
Ministry of Aviation
Royal Aircraft Establishment
Royal Air Force

Comet photo gallery - click the photo to enlarge



Comparison between Comet series 2, 3 and 4B


click on the drawings to enlarge





Boac Comet 4 cut away drawing, 
June 1956 by R.M. Ellis Flight