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De Havilland Comet

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This article is about the de Havilland Comet jet airliner. For the 1930s racing aircraft, see de Havilland DH.88.

Template:Infobox Aircraft

The de Havilland Comet of Britain was the world's first commercial jet airliner. It is infamous for being the first to experience the metal fatigue of jet aircraft due to high flight altitudes.

History

Design work began in 1946 under Ronald Bishop and the intention was to have a commercial aircraft by 1952. The DH 106 Comet first flew on July 27, 1949. At the controls was de Havilland test pilot, John Cunningham, the same man who set a new altitude record two years later in a de Havilland DH 100 Vampire. The design was similar to other airliners except that four of the new, albeit underpowered, de Havilland Ghost 50 Mk1 turbojets were mounted within the wings, in pairs close to the fuselage. This was thought to prove the aircraft more aerodynamic when flying at high speeds. The airliner underwent almost three years of tests and fixes and the first commercial flights did not begin until January 22, 1952 with British Overseas Airways Corporation (BOAC). It became an instant hit with the elite market to whom it was aimed. The first passenger flight was in May from London Heathrow Airport to Johannesburg. The airliner proved to be around twice as fast as contemporary craft and with almost 30,000 passengers carried in the first year over fifty Comets were ordered.


Design flaws

Two separate incidents involving Comets occurred near end of 1952 and beginning of 1953: a BOAC flight failed to become airborne at Ciampino airport near Rome, Italy on October 26, 1952, resulting in minor injuries to passengers, while a Canadian Pacific Airlines Comet 1A collided with a bridge and was destroyed with all hands on takeoff from Karachi, Pakistan next March. These were attributed to a loss of lift from the leading edge of the plane's wing, which was subsequently redesigned.

The first indication of a more serious design flaw, however, came later, on May 2, 1953, when a Comet 1, again of BOAC crashed soon after take-off from Calcutta (now Kolkata), India; further crashes (January and April 1954) off the Italian island of Elba and in Stromboli with no clear cause led to the entire fleet being grounded for investigation. Only after the remnants of the Italian crashes were brought to the surface and analyzed was it found in February 1955, that metal fatigue was the problem. After thousands of pressurised climbs and descents, the thin fuselage metal around the Comet's distinctive rectangular, large windows would begin to crack and eventually cause explosive decompression of the cabin and catastrophic structural failure.

All remaining Comets were either scrapped or modified with window rip-stop doublers and the program to produce a Comet 2 with more powerful Rolls-Royce Avon engines was put on hold. Some Comet 2s were modified to alleviate the fatigue problems and served with the RAF as the Comet C.2. The Comet did not resume commercial airline service until 1958, when the much-improved Comet 4 was introduced.

Variants

Comet 1

The Comet 1 was the first model of the Comet produced. An update Comet 1A was offerered, and some of these were modified to Comet 1XB standard, with strengthened fuselages and round windows, in the wake of the fatigue accidents.

Comet 2

The Comet 2 was a development of the Comet 1, featuring a slightly larger wing, and more powerful Rolls-Royce Avon engines, which improved the aircraft's range and performance. The Comet 2s were allocated to the RAF, where they were known as the Comet Mk. 2s. Eight Comet C.Mk 2 transport aircraft and two Comet T.Mk 2 crew trainers were delivered to the RAF in 1955.

Comet 3

The Comet 3 was a lengthened Comet, with greater capacity and greater range. In the wake of the fatigue accidents, orders dried up, and only two Comet 3s were built, only one of which flew, the other being used for structural testing. The Comet 3 paved the way for the similarly sized Comet 4, serving as a test bed for new technology being developed for that aircraft.

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 October 4, 1958. That flight was the first scheduled trans-Atlantic passenger jet service, beating Pan Am'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. The Comet 4B first flew on June 27, 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. It first flew on October 31, 1959, and Mexicana started Comet 4C services in 1960.

Comet 5

The Comet 5 was a proposed development that would have been a marked improvement over the previous models. Features of the design included a wider fuselage allowing 5 abreast seating, a wing with greater sweep, and pod mounted Rolls-Royce Conway engines, all producing a similar configuration to the Boeing 707 and Douglas DC-8 which were being developed on the other side of the Atlantic. Support from the Ministry of Transport was not forthcoming, and the project did not proceed. Ironically, BOAC, backed by the Department, went on to order Conway powered Boeing 707s.

Hawker Siddeley Nimrod

The Comet 4 was heavily modified to become the Hawker-Siddeley Nimrod, a military aircraft. Before its introduction, maritime patrol aircraft generally used piston or turboprop engines because of better fuel economy, which gave longer flight duration and range.

Nimrod has been the Royal Air Force's primary patrol bomber since 1969. It was originally designed and built by Hawker-Siddeley who had incorporated de Havilland, but is now produced by BAE Systems (formerly British Aerospace which had been formed out of Hawker-Siddeley and other companies). Nimrod serves the RAF in two variants: the Maritime Reconnaissance (MR) role, currently as the MR.2 variant, and the Reconnaissance (R1 variant) an electronic intelligence (ELINT) gathering capacity; officially, these were originally coyly designated "radar calibration aircraft". The R1 is distinguished from the MR2 by the lack of a MAD boom. A new Nimrod, the Nimrod MRA4, is entering service.

Production and service summary

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

Although the Comet was the first jet airliner in service, the interruption of commercial service and the damage to the aircraft's reputation caused by the Comet 1 fatigue failures led to the domination of the jetliner market by Boeing, which flew the first prototype 707 in 1954, and Douglas, which launched the DC-8 program in 1955. Also, for a brief period, the Soviet Union's Tupolev Tu-104 was the jet airliner flying commercially.

Both 707 and DC-8 had better range and passenger accommodations compared to the Comet. The USA has enjoyed a large share of the commercial jetliner market ever since, with their only real competition coming from the later formed Airbus consortium (although Tupolev still manufacture jet airliners at a slow pace).

Only fifteen airlines ever used the Comet. The proposed Comet 5 was never built, and the Comet 4 was slowly withdrawn from service.

Preserved Aircraft

Comet 1

The only complete surviving Comet 1 is a Comet 1XB on display at the RAF Museum Cosford. It is painted in BOAC colours and displays the registration G-APAS[1], although it never flew for that airline, having been delivered to Air France, and then to the Ministry of Supply after conversion to 1XB standard.

The nose of BOAC Comet 1A G-ANAV[2] is displayed at London's Science Museum, while the fuselage of Air France Comet 1A F-BGNX is preserved at the De Havilland Aircraft Heritage Centre in Hertfordshire.

Comet 4

  • Comet C2 'Sagittarius' (Serial XK699 and later maintenance serial 7971M) is the current Gate Guardian at RAF Lyneham in Wiltshire. Lyneham, was previously the operational base for all RAF operated Comets.
  • Comet 4B (Registration G-APYD[3]) is stored at the Science Museum facility at Wroughton in Wiltshire.
  • Comet 4C (Registration N888WA[4]) in BOAC livery is on display at the Museum of Flight, next to Boeing's Seattle factory.
  • Comet 4C (Registration N777WA[5]) is on display at the Parque Zoológico Irapuato in Mexico.
  • Comet 4C (Registration G-APDB[6]) in the colours of Dan-Air is on display at the Imperial War Museum Duxford, England. The plane is part of the Flight Line Display and made available for touring inside during specific times.
  • Comet 4C (Registration G-BDIW[7]) in the colours of Dan-Air is on display at the Flugausstellung Leo Junior at Hermeskeil in Germany.
  • Comet 4C (Registration G-BDIX[8]) in the colours of Dan-Air is on display at the Museum of Flight at East Lothian in Scotland.
  • The last Comet to fly, named Canopus (Military Serial XS235), is kept in running condition at Bruntingthorpe Aerodrome, where it regularly conducts fast taxi runs. There is a campaign to return Canopus to flight, with the current goal to have it in the air by the 50th anniversary of the first regular transatlantic jet service, which started on 4th October 1958.

Military Units using the Comet

Royal Air Force

Royal Canadian Air Force

Specifications (Comet 1)

General characteristics

Performance

Specifications (Comet 4)

General characteristics

Performance

Related content

Related development

Aircraft of comparable role, configuration, and era

Related lists

  1. ^ "G-INFO Database". Civil Aviation Authority.
  2. ^ "G-INFO Database". Civil Aviation Authority.
  3. ^ "G-INFO Database". Civil Aviation Authority.
  4. ^ "FAA Registry (N888WA)". Federal Aviation Administration.
  5. ^ "FAA Registry (N777WA)". Federal Aviation Administration.
  6. ^ "G-INFO Database". Civil Aviation Authority.
  7. ^ "G-INFO Database". Civil Aviation Authority.
  8. ^ "G-INFO Database". Civil Aviation Authority.
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