zoggavia

De Havilland Comet
History of the world's first commercial Jetliner

DH 106 Comet 1


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.




G-ALVG Prototype in an all metal finish during early test flights in 1949
, Zoggavia Collection


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.



G-ALVG Prototype on display at the Farnborough
Air Show 1950, Zoggavia Collection




G-ALVG Prototype in flight during the Farnborough Air Show 1950. Zoggavia Collection

The design 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-ALYR seen at Cairo 1953,  Zoggavia Collection




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, North Africa 1953,
Zoggavia Collection



CF- CUN Canadian Pacific in 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 Naples 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.
 


BOAC Comet 1A G-ALYY just few months before the tragedy, pictured in 1953. Zoggavia Collection

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 at London Heathrow in 1957.
Note the Rolls Royce Avon engine installed. Zoggavia  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

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 Comet 3 prototype in old BOAC colors during her world tour flight. 
Here seen at Kona Intl airport Hawaii in 1955. Zoggavia Collection

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 Air 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.



ST-AAW Comet 4C during a test flight, 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.


Hawker Siddeley HS 801 Nimrod

In July 1963, MOD Air Staff Target (AST) 357 called for a sophisticated, medium-sized, jet-powered, long-range aircraft to replace the piston-engined Avro Shackleton which entered service in 1951 becoming the United Kingdom’s principal Maritime Patrol Aircraft  (MPA). Hawker Siddeley Aviation (formerly De Havilland) made a formal proposal to convert the Comet 4Cturbo-jet powered airliner into a military aircraft (designated HS801). The underside of the Comet fuselage was to be substantially reconfigured to fit a large bomb-bay, extra fuel tanks were to be fitted to give greater range and endurance, and the engines were to be changed from Rolls-Royce Avon engines to Spey 250 engines. In February 1965, it was announced in Parliament that the HS801 had been selected to replace the Shackleton.

Nimrod MR1

The HS801 became the first Nimrod, the Nimrod MR1. The type was designed for anti-submarine and anti-surface unit warfare, surface reconnaissance and for search and rescue operations, i.e. the traditional roles of the MPA. The Nimrod MR1 was equipped with a wide range of radar and acoustic equipment and had the ability to drop sonobuoys, to detect and track submarines, as well as carrying weapons such as torpedoes and Search and Rescue (SAR) equipment. The first flight of a prototype Nimrod MR1 was on 23 May 1967. The first flight of a new-build production Nimrod MR1 was on 28 June 1968.



XV148 Nimrod MR1 Prototype after roll out in 1967.  Zoggavia  Collection


As stated above, the RAF took delivery of its first Nimrod MR1 on 2 October 1969, at RAF St. Mawgan when it was handed to No. 236 Operational Conversion Unit. This was XV230. The 43 Nimrod MR1s were operated primarily from RAF Kinloss, Morayshire, and RAF St. Mawgan, Cornwall. No. 203 Squadron at Luqa, Malta, were also equipped with Nimrods but, following the 1974 Defence Review, this Squadron was disbanded and its Nimrod MR1s flown back to the UK and placed in storage.

Nimrod R1

Three additional airframes were also ordered from Hawker Siddeley to replace the ageing Comet R2s still used  by the RAF for Electronic Intelligence (ELINT) duties. The first of these three extra airframes was delivered to RAF Wyton in July 1971. They were each fitted with a suite of sophisticated and sensitive electronic intelligence-gathering equipment and antennae and were designated Nimrod Reconnaissance Mk 1 (Nimrod R1). The principal external difference from the maritime Nimrod was that they did not have the Magnetic Anomaly Detector probe fitted in the tail. As stated above, the three original Nimrod R1s were built by Hawker Siddeley at Woodford and delivered to the RAF between 1970 and 1973. They were operated by No. 51 Squadron from RAF Waddington. In 1995, a Nimrod R1 (XW666) was lost following an engine fire (see below). It was replaced in December 1996 by the conversion of a Nimrod MR2 (XV249), then in storage at RAF Kinloss, into a Nimrod R1. The Nimrod R1 played a key role in the Falklands Conflict of 1982. Its increasingly important electronic intelligence (ELINT) capabilities have been employed in almost every conflict involving UK forces since then.



On 16 May 1995, XW666, a Nimrod R1 from RAF Waddington ditched in the
Moray Firth 4.5 miles (7.2 km) from Lossiemouth after an engine caught fire during a
post-servicing test flight from RAF Kinloss.
Zoggavia  Collection

Nimrod MR2

In 1975, a comprehensive programme of upgrading the avionics on the MR1 began, including fitting the new Thorn EMI Searchwater radar, a new GEC Central Tactical System and the AQS-901 acoustics system compatible with the latest generation of sonobouys, and the Loral Electronic Support Measures System located in two new wing tip pods. The upgraded aircraft became the Nimrod MR2. A total of 35 Nimrod MR1s were upgraded to the Nimrod MR2 standard by BAE Systems between 1975 and 1984. The first Nimrod MR2 was delivered to 201 Squadron at RAF Kinloss on 23 August 1979. The decision by the Argentinean junta to invade the Falkland Islands in April 1982 gave rise to an Urgent Operational Requirement (UOR) to equip the Nimrod MR2 with an Air-to-Air Refuelling (AAR) capability as part of Operation Corporate. In just 18 days, eight Nimrod MR2s were fitted with in-flight refuelling probes, taken from Vulcans, and stabilising winglets on the tailplane.



XV285 Nimrod MR2, on duty 1985,  Chris Knott Collection

The probes were linked to ordinary ground refuelling hoses running through the cockpit, down the centre aisle of the aircraft and exiting the cabin in the galley area to join the refuel gallery in the wings. The fitting of the AAR capability extended the Nimrod’s endurance to 20 hours in the air. The Nimrod MR2’s self-defence capability was also enhanced by modifying their under-wing hard points to take AIM-9L Sidewinder air-to-air missiles. They flew numerous patrols over the South Atlantic from Ascension Island in support of British operations during the Falklands War. In more recent years, the MR2 were fitted with an electro-optical camera for imagery intelligence (IMINT) tasks.


Nimrod AEW3




XZ286 Nimrod MR1 later converted to AEW3, seen at
Waddington, UK September 1981,  Zoggavia Collection


In August 1972, the RAF issued an AST to replace its Airborne Early Warning (AEW) variant of the Shackleton operated by No. 8 Squadron. In March 1977, the procurement was announced of a specialised version of the Nimrod. This variant would have a large bulbous radome in the nose and tail to house Marconi scanners providing 360º radar coverage. Three AEW3 development aircraft were manufactured and the first one flew on 16 July 1980. A production batch of eight Nimrod AEW3 aircraft was then laid down using a further eight redundant Nimrod MR1 airframes. The first flew on 9 March 1982 and by late 1984 the first ‘interim standard’ Nimrod AEW3 aircraft was delivered by British Aerospace to No. 8 Squadron to allow crew training to commence. In September 1986, however, technical problems with the AEW3 system led to the programme being re-opened to competing bidders. In December 1986 the Boeing E-3 Sentry AWAC was awarded the contract. The Nimrod AEW3 programme was cancelled. The Nimrod AEW3 airframes were stored at RAF Abingdon until they were scrapped in the 1990s.

Nimrod MRA4

In 1993, Air Staff Requirement (ASR) 420 called for a replacement for the MR2. On 25 July 1996, the contract as awarded to BAE Systems who proposed using the existing MR2 airframes, fitting larger wings (127 feet), Rolls-Royce BMW BR.710 engines, new radar and sensor systems and a new tactical computer system. In February 1997, the first three stripped-down Nimrod fuselages were delivered to FR Aviation in Bournemouth, who were contracted to refurbish them. By 1999, however, the programme was three years behind schedule and the first prototype Nimrod MRA4 flight did not take place until 26 August 2004. In September 2004, the planned order for Nimrod MRA4 was reduced from 18 to “ about 12”. The original planned in-service date for the MRA4 was April 2003, but was delayed five times and was planned in 2010.



ZI519 Nimrod MRA4 seen here in 2002,  Zoggavia Collection

The MRA4 was cancelled in 2010 as a result of the Strategic Defence and Security Review at which point it was  £789 million over-budget and nine years late. The development airframes were also scrapped. The cancellation of the MRA4 marked an abortive end of the Nimrod's era; the functions it provided were dispersed to other assets, including the use of unmanned aerial vehicles (UAVs) to conduct maritime surveillance.

to the Comet photo gallery


Summary and technical data of the Comet


   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 Power-
plant
 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
   Passenger 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.
1958

 1.4.
1960
 1960


Summary and technical data
of the Nimrod

   Nimrod Series
R1
MR2
AEW3
MRA4
Dimensions
Length
(m)

36,19 38,65 41,97 38,6
   Wingspan
(m)

35.00
 35,00 35,08
38,71
   Height
(m)

 9.14 9,86
10,67
9,45
  Wing Area
(m2)

 197.05 197,05
197,05
235,8
Weight
Take off
(t)

87.1
 89,10 85,19
 105,40
  Fuel capacity
(l)

 46'628 46'500
46'500
42'468
 Propulsion Power-
plant
RR
Spey 521
RR
Spey 520
 RR
RB168
RR/BMW
BR710
  Thrust
(KN)

216
 216  216  276
 Performance  Speed
(km)

 780 -
920
920 850
 920
  Range
(km)

 9254  9266 9200
 11119
  Aircrew
 
29
12
10
 10
 First Flight
 Date 23.5.
1967

 1975
16.7.
1980

 19.7.
1954
 First Service
Date
2.10.
1969
08.
1979
planned
1986
 26.08.
2004
Retired Date 28.6.
2011
31.03.
2010
19.10.
2010*
*Cancellation of the program


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