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Concorde (/ˈkɒŋkɔːrd/) is a retired Anglo-French supersonic airliner jointly developed and manufactured by Sud Aviation (later Arospatiale) and the British Aircraft Corporation (BAC).Studies started in 1954, and France and the UK signed a treaty establishing the development project on 29 November 1962, as the programme cost was estimated at 70 million (1.39 billion in 2023).Construction of the six prototypes began in February 1965, and the first flight took off from Toulouse on 2 March 1969.The market was predicted for 350 aircraft, and the manufacturers received up to 100 option orders from many major airlines.On 9 October 1975, it received its French Certificate of Airworthiness, and from the UK CAA on 5 December.[4]
Concorde is a tailless aircraft design with a narrow fuselage permitting 4-abreast seating for 92 to 128 passengers, an ogival delta wing and a droop nose for landing visibility.It is powered by four Rolls-Royce/Snecma Olympus 593 turbojets with variable engine intake ramps, and reheat for take-off and acceleration to supersonic speed.Constructed out of aluminium, it was the first airliner to have analogue fly-by-wire flight controls. The airliner could maintain a supercruise up to Mach 2.04 (2,170 km/h; 1,350 mph) at an altitude of 60,000 ft (18.3 km).
On 25 July 2000, Air France Flight 4590 crashed shortly after take-off with all 109 occupants and four on the ground killed. This was the only fatal incident involving Concorde; commercial service was suspended until November 2001.The Concorde aircraft were retired in 2003, 27 years after commercial operations had begun. All but 2 of the 20 aircraft built have been preserved and are on display across Europe and North America.
The origins of the Concorde project date to the early 1950s, when Arnold Hall, director of the Royal Aircraft Establishment (RAE), asked Morien Morgan to form a committee to study the supersonic transport (SST) concept. The group met for the first time in February 1954 and delivered their first report in April 1955.[5] At the time it was known that the drag at supersonic speeds was strongly related to the span of the wing.[N 1] This led to the use of short-span, thin trapezoidal wings such as those seen on the control surfaces of many missiles, or in aircraft such as the Lockheed F-104 Starfighter interceptor or the planned Avro 730 strategic bomber that the team studied. The team outlined a baseline configuration that resembled an enlarged Avro 730.[6]
This same short span produced very little lift at low speed, which resulted in extremely long take-off runs and high landing speeds.[7] In an SST design, this would have required enormous engine power to lift off from existing runways and, to provide the fuel needed, "some horribly large aeroplanes" resulted.[6] Based on this, the group considered the concept of an SST infeasible, and instead suggested continued low-level studies into supersonic aerodynamics.[6]
Soon after, Johanna Weber and Dietrich Kchemann at the RAE published a series of reports on a new wing planform, known in the UK as the "slender delta" concept.[8][9] The team, including Eric Maskell whose report "Flow Separation in Three Dimensions" contributed to an understanding of the physical nature of separated flow,[10] worked with the fact that delta wings can produce strong vortices on their upper surfaces at high angles of attack.[6] The vortex will lower the air pressure and cause lift to be greatly increased. This effect had been noticed earlier, notably by Chuck Yeager in the Convair XF-92, but its qualities had not been fully appreciated. Weber suggested that this was no mere curiosity, and the effect could be used deliberately to improve low speed performance.[9][6]
Kchemann's and Weber's papers changed the entire nature of supersonic design almost overnight. Although the delta had already been used on aircraft prior to this point, these designs used planforms that were not much different from a swept wing of the same span.[N 2] Weber noted that the lift from the vortex was increased by the length of the wing it had to operate over, which suggested that the effect would be maximised by extending the wing along the fuselage as far as possible. Such a layout would still have good supersonic performance inherent to the short span, while also offering reasonable take-off and landing speeds using vortex generation.[9] The only downside to such a design is that the aircraft would have to take off and land very "nose high" to generate the required vortex lift, which led to questions about the low speed handling qualities of such a design.[11] It would also need to have long landing gear to produce the required angle of attack while still on the runway.
Kchemann presented the idea at a meeting where Morgan was also present. Test pilot Eric Brown recalls Morgan's reaction to the presentation, saying that he immediately seized on it as the solution to the SST problem. Brown considers this moment as being the true birth of the Concorde project.[11]
STAC stated that an SST would have economic performance similar to existing subsonic types.[6] A significant problem is that lift is not generated the same way at supersonic and subsonic speeds, with the lift-to-drag ratio for supersonic designs being about half that of subsonic designs.[14] This means the aircraft would have to use more power than a subsonic design of the same size. But although they would burn more fuel in cruise, they would be able to fly more sorties in a given period of time, so fewer aircraft would be needed to service a particular route. This would remain economically advantageous as long as fuel represented a small percentage of operational costs, as it did at the time.[6]
STAC suggested that two designs naturally fell out of their work, a transatlantic model flying at about Mach 2, and a shorter-range version flying at Mach 1.2 perhaps. Morgan suggested that a 150-passenger transatlantic SST would cost about 75 to 90 million to develop, and be in service in 1970. The smaller 100 passenger short-range version would cost perhaps 50 to 80 million, and be ready for service in 1968. To meet this schedule, development would need to begin in 1960, with production contracts let in 1962.[6] Morgan strongly suggested that the US was already involved in a similar project, and that if the UK failed to respond it would be locked out of an airliner market that he believed would be dominated by SST aircraft.[15][N 3]
In 1959, a study contract was awarded to Hawker Siddeley and Bristol for preliminary designs based on the slender delta concept,[16] which developed as the HSA.1000 and Bristol 198. Armstrong Whitworth also responded with an internal design, the M-Wing, for the lower-speed shorter-range category. Even at this early time, both the STAC group and the government were looking for partners to develop the designs. In September 1959, Hawker approached Lockheed, and after the creation of British Aircraft Corporation in 1960, the former Bristol team immediately started talks with Boeing, General Dynamics, Douglas Aircraft, and Sud Aviation.[16]
Kchemann and others at the RAE continued their work on the slender delta throughout this period, considering three basic shapes; the classic straight-edge delta, the "gothic delta" that was rounded outward to appear like a gothic arch, and the "ogival wing" that was compound-rounded into the shape of an ogee. Each of these planforms had its own advantages and disadvantages in terms of aerodynamics. As they worked with these shapes, a practical concern grew to become so important that it forced selection of one of these designs.[17]
Generally one wants to have the wing's centre of pressure (CP, or "lift point") close to the aircraft's centre of gravity (CG, or "balance point") to reduce the amount of control force required to pitch the aircraft. As the aircraft layout changes during the design phase, it is common for the CG to move fore or aft. With a normal wing design this can be addressed by moving the wing slightly fore or aft to account for this.[N 4] With a delta wing running most of the length of the fuselage, this was no longer easy; moving the wing would leave it in front of the nose or behind the tail. Studying the various layouts in terms of CG changes, both during design and changes due to fuel use during flight, the ogee planform immediately came to the fore.[17]
To test the new wing, NASA privately assisted the team by modifying a Douglas F5D Skylancer with temporary wing modifications to mimic the wing selection. In 1965 the NASA test aircraft successfully tested the wing, and found that it reduced landing speeds noticeably over the standard delta wing. NASA Ames test center also ran simulations that showed the aircraft would suffer a sudden change in pitch when entering ground effect. Ames test pilots later participated in a joint cooperative test with the French and British test pilots and found that the simulations had been correct, and this information was added to pilot training.[19]
By this time similar political and economic concerns in France had led to their own SST plans. In the late 1950s, the government requested designs from both the government-owned Sud Aviation and Nord Aviation, as well as Dassault.[N 5] All three returned designs based on Kchemann and Weber's slender delta; Nord suggested a ramjet powered design flying at Mach 3, and the other two were jet-powered Mach 2 designs that were similar to each other. Of the three, the Sud Aviation Super-Caravelle won the design contest with a medium-range design deliberately sized to avoid competition with transatlantic US designs they assumed were already on the drawing board.[20]
As soon as the design was complete, in April 1960, Pierre Satre, the company's technical director, was sent to Bristol to discuss a partnership. Bristol was surprised to find that the Sud team had designed a similar aircraft after considering the SST problem and coming to the very same conclusions as the Bristol and STAC teams in terms of economics. It was later revealed that the original STAC report, marked "For UK Eyes Only", had secretly been passed to France to win political favour. Sud made minor changes to the paper and presented it as their own work.[21]
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