de Havilland started work on the
pioneering Comet 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. Production started on
an initial order of 8 in 1947.
The new aircraft was a huge advancement in aerodynamics,
materials and performance. It had a highly pressurized
cabin and with it's 4 de Havilland Ghost turbo jets, it
could fly much higher and faster than previous airliners.
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Pushing the boundaries carries
a risk. Unfortunately the flight tests had
little chance of finding the metal fatigue that
would cause the fuselage to fail after prolonged
use.
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The prototype first flew on 27th July 1949 and
BOAC took delivery in 1951 putting the new aircraft into
evaluation on a number of routes.
Weight was a concern for the early Comet. The DH
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
break up of the aircraft. It has been revealed recently
that some did suspect that the Comet was under strength
and was rushed though its testing program. However,
no one really knew the facts for certain and the doubts
were clearly not great enough to halt the launch of the
aircraft.
After very successful trials, the BOAC Comets started
the worlds first jet passenger service in May 1952, London
Heathrow to Johannesburg.
There were 3 crashes in the first year. Two were
put down to pilot error, with over rotation on takeoff
blamed. Another was put down to an in flight break
up due to the turbulence of a tropical storm. However
when another two broke up in flight in 1954, the aircraft's
air worthiness certificate was revoked and the Comet was
grounded.
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.
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the early setbacks, the re-launched Comet
4 still managed to become the first passenger
jet to operate across the Atlantic Ocean. |
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To their enormous credit, de Havilland immediately
came clean and 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. But the earlier
Comets were discarded by the airlines.
A number of further improvements eventually
saw the Comet reintroduced as the Comet 4 in 1958.
It had a much longer fuselage than the earlier Comets
and also included external fuel tanks on the wings, giving
extended range. It was powered by 4 Rolls Royce
Avon engines. BOAC kept faith with the Comet and
placed a significant order.
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longer 4B was made specifically for BEA’s
routes. It had a higher capacity, but
a shorter range than the Comet 4. |
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BOAC started the world’s first jet passenger service
across the Atlantic, New York to London, with the Comet
4 on 4th October 1958. It only beat the Boeing 707
to this record by a few weeks.
The 4B was designed specifically for BEA,
to service its shorter range routes. It featured
a slightly extended fuselage to seat up to 99 passengers
and slightly shorter wings with no fuel tank pods.
It entered service with BEA at the end of 1959.
The only other airline to order the 4B was Olympic, who
took two. Only 18 Comet 4Bs were built.
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The definitive 4C
was mainly sold to overseas customers such
as Mexicana, MEA, Sudan and United Arab.
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The 4C was a combination
of the 4’s wings and the 4B’s fuselage, giving both higher
capacity and longer range. This aircraft was mainly
sold to overseas customers, but was also taken by the
RAF. The final production total for all of the Comet
4 variants was 76. The total across the whole Comet
range was 113.
Other variants of the Comet were proposed, including a
Comet 5 but none got past the initial design stage. The
Comet design did live on into the next era though when
the Comet 4 was used by the RAF as the airframe base of
the Nimrod maritime reconnosance aircraft.
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last stop for any Comet that still had any
flying in it. Dan-Air bought most of
the Comets and was the only operator of the
type by 1975. |
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By 1975 the only commercial operator of the Comet
was Dan-Air, who became synonymous with the aircraft.
Dan-Air bought 44 of the remaining aircraft, but most
of these were used as spare parts to service the fleet,
which never exceeded 18 at one time. The fleet declined
each year, with only 6 4C’s managing to reach the 1980’s.
The final Dan-Air Comet was retired early in 1982.
The Comet was never taken on in great numbers, due in
part to it's early reputation, but mainly because those
early setbacks allowed the competition time to to catch
up.
The Comet 4 did go on to prove itself as a sound and reliable
aircraft. It gave many years service and rebuilt
the Comet name, so that it could rightly be remembered
with pride as the World's first jet airliner.
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then there was one. ‘Canopus’ was the last
flying example and is still kept in working
order, but only on the ground. But hopefully
one day... |
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There are no Comets flying today, although there
are many static examples at Museums around the world.
There is only one example of a fully intact Comet 1 though,
at Cosford.
The last flying example, ‘Canopus’ of the Royal Aircraft
Establishment, has been kept in working order by enthusiasts,
with regular ground runs. It was hoped that this
aircraft would be returned to flying condition, but this
now seems unlikely.
It can still be seen doing fast taxi runs at the regular
open days at Bruntingthorpe near Leicester.
(Article by David Maltby)
DH106 Comet 4B data
Accommodation: 3-4
Crew & 71-101 passengers
Engines: 4 Rolls-Royce Avon 525 turbojets
10,500lb st
Span: 107ft 10in
Length: 118ft
Gross weight: 158,000lb
Max payload: 23,900lb
Max cruise: 526mph at 23,500ft
Range: 3,120 miles with max payload at 462mph
data Civil Airliner Recognition
1973
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