de Havilland Comet 1A / XB (G-APAS)

de Havilland Comet 1A / XB (G-APAS)  [@ RAF Cosford]

Rightly to be remembered with pride as the world's first jet airliner, seemingly securing Britain in first place in the post-war civil aviation industry.  The new aircraft was a huge advancement in aerodynamics, materials, performance and therefore could fly much higher and faster than previous airliners. The de Havilland Company started work on the pioneering design following the Brabazon Committee's proposals for commercial aviation in 1943.  A design for an aircraft to fly the Atlantic at 500 mph was proposed and was accepted by BOAC (British Overseas Airways Corporation) with production starting on an initial order of eight in 1947.  With a cruising speed of 450 mph (725k/h) and a range of 2500 miles (4024 km), the Comet established many records.  With four jet engines and a pressurised cabin, it offered unprecedented levels of comfort and speed for the 36-40 passengers.  The original Ghost engines were not really powerful enough to carry the weights required by the airlines.  The Ghost was accepted by BOAC as an interim measure while the more suitable Rolls Royce Avon was developed.  Weight was saved by the extensive use of metal bonding rather than traditional rivets and also by using very thin gauge aluminium on the fuselage.  This contributed greatly to the metal fatigue which would later cause the demise of the aircraft.

Two prototypes were built, 06001 and 06002, and registered as G-ALVG, and G-ALZK respectively.  The first flew on 27th July 1949 and was in the capable hands of Group Captain John "Cat's Eyes" Cunningham and the second one first flew on 27th July 1950 with BOAC taking delivery of the first Comet 1 on 22nd March 1951.The first prototype was broken up in July 1952 and the second underwent a similar fate in July 1957.  One again wonders why such an important historical aircraft was not preserved.  Probably the greatest legacy of the Comet was when the Comet  4 airframe was chosen by the RAF as a basis of the world renowned Nimrod maritime reconnaissance aircraft.

de Havilland Comet 1A / XB (G-APAS)

de Havilland Comet 1A / XB (G-APAS)  [@ RAF Cosford]

The Comet 1 first flight was on 9th January 1951 and it entered service on the 22nd March 1951.  The main difference between it and the prototypes was the incorporation of the four wheel main bogie, an additional window and a different layout of the emergency exits.  BOAC Comets started the world’s first jet passenger service on 2nd May 1952, London Heathrow to Johannesburg.  The Comet 1A, whose first customer was Canadian Pacific Airlines, first flew on 11th August 1952 and had a reinforced structure, a centre tank for additional fuel and Ghost 50 Mk2 engines.  The sixth Comet 1 frame was used to test the Rolls Royce Avon RA.9 Mk 501/502 engines, which were intended to power the Comet 2.  The Comet 2X first flew on 16th February 1952 powered with four Avon engines.

Unfortunately several disasters were to befall the Comet; in 1952 and 1953 there were take-off accidents and a Comet broke up in a violent storm over India.  On 10th January 1954 a Comet belonging to BOAC crashed soon after a takeoff into the Mediterranean whilst en route from Rome to London.  A few weeks latter a Comet on its way to Johannesburg crashed into the sea near Naples after takeoff from Rome, resulting in withdrawal of the Certificate of Airworthiness for all Comet 1s.  Only 9 Comet 1s were built, 5 of which crashed, plus 10 Comet 1As, 3 of which crashed.  This event sparked the largest accident investigation effort that the world had ever seen, establishing the British as world leaders in accident investigation.  The Comet parts were rebuilt in a hangar as engineers searched for a cause.  Another Comet was submerged in a huge water tank and was repeatedly pressurized to quickly simulate hundreds of flights.  After one of these caused a rupture in the fuselage, they had the answer, metal fatigue.  The repeated change in pressure had weakened the metal where the loadings were concentrated at the corner of a window panel.  The de Havilland published all of their data and findings to prevent more possible problems.  This however effectively handed the market to Boeing and Douglas, with their up coming 707 and DC-8 projects also able to take full advantage of the de Havilland research.  The fuselage was strengthened and the windows were redesigned.  The original square shape was changed to an oval, to dissipate the load.

G-APAS is the only example of a fully intact Comet 1.  With serial number 06022 it was delivered to Air France on July 1953 as a Comet 1A and was one of only four Comet 1As to be upgraded to XB standard - notice the shape of the windows.

de Havilland Comet 1A (F-BGNX)

de Havilland Comet 1A (F-BGNX)  [@ de Havilland Aircraft Heritage Centre]

The photograph shows the cockpit of a complete fuselage, with original square shaped windows, of another ex Air France aircraft.  It was used for tests at Farnborough after withdrawal from service.

The first aircraft to benefit from this research was the Comet XB, a converted Comet 1A.  In addition the engines were upgraded to Ghost 50-Mk4s but only 4 Comet 1As was upgraded to XB standard.  The earlier Comets were discarded by the airlines.  The Comet 2 had a stretched fuselage, modified drooped leading edges, four Avon RA.25 Mk 503/504 engines and a fuel capacity was identical to an Comet 1A.  The first flight took place on 27th August 1953 but unfortunately the Comet 2 was never used in commercial operation since the Comet 1 disaster forced its production to stop.  Out of the twenty two Comet 2s that were built; five were scrapped, three were stored and the rest were converted to other standards.  The RAF operated eight Comet 2s as the Comet C.2 variant.  Fitted with oval windows, the fuselage and cabin floor were reinforced but a restriction was placed on the number of sorties the airframe could undergo.  The Comet T.2 was identical to the C.2 but without the reinforced floor while the Comet 2R variant was unpressurized and had the original Comet 2 frame with square windows but was powered by Avon Mk 117 engines.  The Comet 2E was a Comet C.2 fitted with two Avon RA.29 Mk 524 engines in the outer positions.  This was the engine later used by the Comet 4.  The engines in the inner positions were two Avon RA.25 Mk 504.

de Havilland Comet 2

de Havilland Comet 2  [@ de Havilland Aircraft Heritage Centre]

The Comet 3 herald a change in the basic Comet design.  It included a stretched fuselage, oval windows, a higher fuel capacity due to pinion tanks and Avon RA.26 Mk 522 engines.  The jet exhaust pipes were moved to the outer-line to reduce noise and corrosion.  The first flight took place on 19th July 1954.  Due to the Comet 1 problems the Comet 3 program was abandoned, ten frames were scrapped, however the Comet 3 frame was used to develop the definitive Comet 4 variant.  The original Comet 3 was converted in 1958 to the Comet 4B specification, thus resulting in the only Comet 3B.  The modification was realized by removing the pinion tanks and its first flight took place on 21st August.

The photograph shows the nose of a non-completed Comet 2 which was later converted to a Comet 4 flight simulator.

de Havilland Comet C.4 (XR399) (G-BDIX)

de Havilland Comet C.4 (XR399) (G-BDIX)  [@ RAF East Fortune]

The Comet 4 was a highly modified Comet 3; it used a different alloy for the fuselage, a higher differential pressure than the earlier Comets and also included external fuel tanks on the wings, giving extended range.  It was powered by four Rolls Royce Avon engines.  The first flight took place on 27th April 1958 with the first delivery being on 30th September 1958 to BOAC.  Since most of the certification had been completed by the Comet 2E and Comet 3 the Comet 4 was placed in service in October 1958.  In fact BOAC started the world’s first jet passenger service across the Atlantic, New York to London, with the Comet 4 on 4th October 1958 and another first for British innovation.  It only beat the Boeing 707 to this record by a few weeks.  A total of twenty-eight Comet 4s were built.  The Comet 4A was launched in June 1956 as a short range version of the Comet, it had with a stretched fuselage and reduced wing span.  Unfortunately no Comet 4As were built as the launch customer Capital Airlines cancelled the order.  Following on was the Comet 4B which was also intended for shorter range operations and was specifically designed for BEA (British European Airways).  The shorter wing of the Comet 4A was kept but the pinion tanks were removed, resulting in a smaller fuel capacity.  The fuselage of the Comet 4B was stretched even further to seat up to 99 passengers and 4 Avon RA29 Mk 525 were fitted.  The outer engines were equipped with a thrust reverser and noise was also reduced compared earlier versions.  The first flight took place on 27th June 1959 and a total of 18 Comet 4Bs were built and the only other airline to order the Comet 4B was Olympic who took delivery of two.  The Comet 4C was the classic variant, a combination of the fuselage from the Comet 4B and the wings of the Comet 4, giving both higher capacity and longer range and with the same engine configuration as the Comet 4B.  The first flight took place on 31st October 1959 with first delivery on the 14th January 1960.  A total of twenty-three comet 4Cs were built and were mainly sold to overseas customers such as Mexicana, MEA, Sudan and United Arab and five were operated by the RAF as Comet C.4s.  The Comet 4C did go on to prove itself as a sound and reliable aircraft.

Serial number 06471 was delivered to the RAF Transport Command as a Comet C.4 in April 1962 as XR399.  One of only five of this type operated by the RAF it retired from service in 1975 and went on to become one of the last Comets to see commercial service as 'G-BDIX' with Dan Air London.  Finally retiring in 1980 it was flown from Lasham in Hampshire to RAF East Fortune in September 1981 to become the last Comet to fly in commercial colours.

de Havilland Comet "Canopus" 4C (XS235)

de Havilland Comet "Canopus" 4C (XS235)  [@ RAF Bruntingthorpe]

By 1975 the only commercial operator of the Comet was Dan-Air, who became synonymous with the aircraft.   Dan-Air bought forty-four of the remaining aircraft; most of these were used as spare parts to service the fleet, which never exceeded eighteen serviceable aircraft.   The fleet declined each year, with only six 4C’s managing to reach the 1980’s.  The last flight of a Dan-Air Comet was in 1980 after which the only Comets to remain in service were with the RAF and the Development and Research Agency.  By 1996 the very last flying example, XS235 Canopus, was becoming expensive to maintain and the decision was taken to put it up for sale.  A Comet 5 was proposed to counter the success of the DC-8 and the B-7075 but it never got past the initial design stage.  The total number of units across the entire Comet range was one hundred and thirteen.

In 1963 de Havilland Comet 4C XS 235 “Canopus” was delivered straight from the production line at Chester to Royal Aircraft Establishment at Boscombe Down as a trials aeroplane.  For the next thirty-three years it led a sedate life, amassing only 8,200 flying hours.  Too expensive to maintain “Canopus” was up for auction in May 1997 but there were fears that this most historic aeroplane would be bought by a foreign collector.  The National Air Pageant, supported by Lord Brabazon of Tara, petitioned the Defence Secretary to withdraw this important piece of Britain's national heritage.  Thankfully the sale was cancelled and XS235 was sold to the de Havilland Aircraft Museum Trust but unfortunately plans to fly it to Hatfield, birthplace of the Comet, fell through.  Eventually “Canopus” was rescued by British Aerospace and became the last flying Comet when it flew into RAF Bruntingthorpe on 30th October 1997.  Although it remains in taxiing condition in the care of the British Aviation Heritage Collection, it was hoped that this aircraft would be returned one day to flying condition but this now seems very unlikely.