It is a considerable tribute to Concorde’s creators that an aircraft designed in the mid-1960s still looked futuristic when it retired in 2003. Could the same be said of contemporaries such as the McDonnell Douglas DC-9 or BAC 1-11? Probably not.
In Concorde’s case, function determined form to a greater extent than it would normally. An airliner designed to handle the stresses of Mach 2 flight was always going to look out of the ordinary. But the way in which the design teams in France and the UK crafted a machine that utilised cutting-edge technology with such elegance was remarkable.
Even the mock-up at BAC’s Filton factory was described by Flight in March 1967 as “shapely, beautiful, and so tall that she seems to be not so much resting on her undercarriage legs as to be held aloft by them”.
The aircraft’s aerodynamics – particularly the wing – excited much favourable comment among this publication’s writers at the time. Later that year, one article noted that the ogee delta plan-form used for Concorde had been “skilfully contrived in the late 1950s by the aerodynamicists of the Royal Aircraft Establishment, Bedford, to incorporate maximum span (for minimum induced drag) and minimum area (for minimum profile drag)”. Deltas were regarded as the most favoured plan-form for supersonic airliners because of their aerodynamic efficiency in cruising flight, combined with few structural problems.
Among the advantages of a slender delta such as Concorde’s were “the important characteristic of not stalling in the accepted sense", according to Flight. "The lift coefficients of these wings continue to increase up to very high angles of incidence… because of the leading-edge vortices, which strengthen as incidence increases.”
For the powerplant, the aircraft’s design teams opted for the Rolls-Royce/Snecma Olympus 593, a highly developed version of the classic two-spool turbojet used in the Avro Vulcan nuclear bomber and then, in modified form, for the ill-fated BAC TSR-2 strike/reconnaissance aircraft.
Jean Calmon, the director at Snecma responsible for the project, said at the time of Concorde's retirement that developing the powerplant was a difficult task “as we had to constantly upgrade its performance – the power of the Olympus 593 grew 14% before Concorde flew".
“We had to make technological leaps in the materials used and the manufacturing processes: the combustion, the aerodynamics of the exhaust nozzles and the electronic control systems," he said. “Our inability to reduce the engine noise was a major disappointment, although the best UK and French acoustic specialists were mobilised from 1967.
"In 1970, SNECMA initiated technical exchanges with General Electric, which was developing the engine for the US supersonic project. Numerous configurations of silencer were tested, but we never managed to tame the noise of the jet. For SNECMA, Concorde was an indispensable and decisive stage in its move to civilian aerospace and prepared the ground for the successful CFM56 programme developed with GE.”
The technology that supported the Olympus included the highly sophisticated variable-geometry intake that helped "condition" the air for the engine. Supersonic compression was carried out externally through a system of shockwaves. The airstream speed was reduced to less than Mach 1 and the air was then further compressed in a subsonic diffuser to a speed acceptable to the engine. Concorde was the first civil airliner to use such technology.