There are no ivory towers for the designer of commercial aircraft for the simple reason that his product has to be what that term for it implies: a commercial proposition. He cannot work successfully in isolation from market considerations. The joint proposal for a supersonic airliner put forward by Sud-Aviation and BAC was a merging of the two separate approaches to the problem: the French medium-range approach and the British long-range approach. Within the same overall dimensions, the joint design team was offering a 100seat medium-range vehicle and a heavier 90-seat long-range vehicle.

Selling an idea

An input was also needed from the market. What was the reaction of the potential customers among the airlines to the preliminary proposals? Before the designers went too far down the road with their own ideas, they must discover what the operators were thinking. So, in the early months of 1963, the sales teams were out on the road making their first presentations of Concorde to major airlines. These were Anglo-French teams, and there has been close integration of the marketing effort ever since those early days. If the airline being visited was one with which Sud Aviation had had the closer contact in the past, then a Frenchman led the presentation team; if the visit was to a BAC contact, a Briton led.

The reception given to the marketing teams by the airlines was generally friendly, but could not, by any stretch of the imagination, have been described as enthusiastic. This was hardly to be wondered at since many of them were either facing, or expecting to face, problems of over-capacity caused by the introduction of the new generation of subsonic jetliners. With too many seats chasing too few passengers, the operators could hardly be expected to welcome the prospect of a new type of airliner making their equipment obsolescent.

Apart from this, there were several specific criticisms of the preliminary proposals. There was a general acceptance of the Anglo-French design philosophy of a Mach 2.2 aluminium alloy airliner, but there were reservations about payload and about the fuel reserve allowances that the designers had made in their estimates.

The 90-seat payload proposed for the long range aircraft was thought to be too small to enable an economic operation to be carried on. More capacity was essential in the airline view, despite the makers' arguments that the high speed of Concorde would give it the productivity of a subsonic aircraft twice its size (because, in a given time, Concorde could produce twice the number of "seat-miles" produced by the subsonic type).

Fuel reserve policies vary considerably from airline to airline. Normally when an aircraft manufacturer makes a presentation of a new type to a potential customer he will know that customer's policy on reserves, and will use this figure in making his forecasts of how his aircraft will perform in the airline's service.

Concorde's manufacturers had felt, with the support of some national aviation authorities such as the USA's Federal Aviation Administration, that fuel reserve allowances for a supersonic airliner should not necessarily be the same as those for a subsonic airliner. There were sound reasons for this view, notably the fact that, at the much higher cruise altitudes, atmospheric conditions are calmer, there is less wind and consequently fuel requirements can be more precisely calculated in advance. These and other arguments have come to be more generally accepted in recent years and new supersonic fuel reserve policies are being formulated, but in 1963 any suggestion of lower fuel reserves was firmly rejected.

An even more important reaction from this first round of talks with the airlines was that any customer interest in a supersonic airliner was centred on the long-range proposal. The marketing teams reported that for the time being, it would be necessary to concentrate the joint design effort on modifying and developing the long range version to get it closer to the airline requirement. With some understandably reluctance on the part of the French, design work on the medium-range version was discontinued and has never since been revived

Thus the verdict of the market had gone in favour of the British view that the first generation SST must be a design with Transatlantic range. This point is not made here in a spirit of nationalism. The French arguments for the medium-range version had much force and logic behind them, and it will be recalled that the British Supersonic Transport Aircraft Committee had itself put forward proposals for both a long range and a medium-range SST. The real significance of this decision, taken so early in the project, was that it was made in response to market opinion.

The general impression gained by the sales teams was that they had been told by the operators: "Back to the drawing board my friends, and come and see us again when you have done a whole lot more work to this supersonic aeroplane of yours." Despite this, in June, 1963 Pan American took an option on six Concordes followed by Continental Airlines (three) in July, American Airlines (four) in October and TWA (four) in November. It was also agreed that the first 18 Concordes should be delivered on rotation six to Pan Am, six to BOAC (as it then was and six to Air France.

The threat of U.S. competition

If the Pan American motive had partly been to inject more urgency into the American SST project, it had the desired effect. Within a day or so President Kennedy proclaimed his government's intention to support the American aircraft industry in developing and building a supersonic transport that would be bigger and faster than the Concorde. An options list was opened and many of the world's leading airlines, including all those on the Concorde option list, put their names down for the American aircraft. The aim was to get it into service within two or three years after Concorde, and, in view of the American industry's great reputation for getting things done on time, this announcement caused some concern in Britain and France.

This concern was not fully shared by the Anglo-French design team. If the Americans really were going for a Mach 3 (or even, as it later became, a Mach 2.7) SST built in titanium, the Concorde men were convinced that, even with the USA's immense resources and enormous drive, it would take at least a decade to get their aircraft into service. To carry the 75,0001b. payload being spoken of would mean a take-off weight of not less than one million pounds. The aircraft would be at least 300 feet long

(The length of a football field), and the structural problems of building an airframe of that length in titanium were mind boggling. At the very least, Concorde would have a five-year lead over the American aircraft.

What really concerned the Concorde's makers, in 1963 and later when the American SST was cancelled, was that the Americans might change their minds about cruise speed and elect to build a Mach 2.2 airliner. This would have been a much more worrying prospect.

In their predictions about the American SST problems, the Concorde designers were right. In their predictions about their own entry into service date, they were years out. The design problems that lay ahead for them might not be of the same magnitude as those which brought the American SST to a halt, but they were still sufficiently formidable to throw an optimistic timetable well out of gear. To get the required greater passenger carrying capacity in the long-range version meant carrying more fuel and that meant increased take-off weight and that, in turn, meant more engine power. It is a familiar story in aviation, and especially to the engine manufacturer, who sometimes feels that he is "tail-end Charlie" in this situation.

Meeting the client's needs

However, like all good engine designs the Olympus 593 had development, or "stretch," potential, and the engine manufacturers were able to offer an increase in power sufficient to meet the first aircraft growth stage. This stage took the all-up weight from the 262,0001b. of the preliminary design up to 286,0001b. and the seating capacity from 90 to 100. The first airline response to this increase was not encouraging; it was regarded as no more than a step in the right direction.

Further progress depended on greater engine power, and Bristol Siddeley and SNECMA decided on a redesign of the Olympus to provide a reserve, not only for the immediate situation but for the future weight increases that would occur in Concorde development as they do in every other civil aircraft programme. The new engine was given the designation 593B.

With the assurance of additional power the redesign of the aircraft could go forward. An increase was made in the wing and fin area, additional under floor fuel tankage was provided and, to compensate for the loss of baggage space that this caused, extra space for baggage stowage was provided in the rear fuselage. This was made available by eliminating the ventral passenger door originally proposed and substituting for it a second port side door.

These changes had the effect of increasing the maximum take-off weight to 326,0001b. and the passenger capacity to 118. Although development went on for much of 1964, this design was essentially the Concorde prototype design. Early in 1965 it was "frozen" (which meant that no major changes were to be subsequently introduced) and the first metal was cut for the two prototype aircraft.

By then BOAC, Air France and Pan American had each increased their options from six to eight, Middle East Airlines and Qantas had joined the options list; and the total number of options had risen to 43. In the short space of twelve months there had been an astonishing transformation in the market prospects for Concorde.

This account of Concorde development has so far been mainly concerned with the policy makers, and the designers and the marketing men. It is now time to give some attention to the production men; the engineers, the planners, the progress chasers, the foremen and charge-hands, the machinists and the fitters all those people who sometimes lump themselves together under the mock modest title of "tin-bashers."

Building the first Concordes was, by any standard, a formidable engineering task. More than 100,000 detail drawings were issued to the production organisation. The parts list for the aircraft finally contained more than a quarter of a million items, and a "part number" could refer to a single small bolt or to a large bought-out component like a generator (which would itself be made up of hundreds of separate parts). Nobody ever had the time to work out just how many separate parts went into the building of a Concorde prototype, but the total certainly exceeded one million.

It would be quite wrong to give the impression that in the two years, 1963 and 1964, when the design was moving forward from the preliminary to the prototype stage, the production engineers were held up for work. The agreement on the manufacturing breakdown, to which they had contributed, enabled them to begin their planning in earnest

There were shops to be laid out and men to be trained, new machine tools to be ordered and transport requirements to be worked out. Above all, there was the essential job, for the top production men, of "getting to know the French" (or the English). Initially, most of the Anglo-French contacts had been at the design level. Now, the manufacturing men had to talk together to discover how best they could work together. In this field, too, French and British engineers have proved that they make a most effective partnership, founded on mutual respect and on a common faith in the project.

While the production planning was going on, machine and assembly shops were gaining experience in handling the new (to them) RR58 aluminium alloy by building test specimens. These were small assemblies at first, but gradually increased in size until major components were being produced for the laboratories. As had been expected, the new material presented no serious problems for the machine shops; it could be handled and fabricated using techniques that were already tested and proved, which was one of the reasons why it had been selected.

Sculpture milling

One of those techniques is the process known as sculpture milling or machining from the solid, using tape-controlled machine tools. In this process, the modern production engineer has gone back to the principles of the primitive dug-out canoe. Instead of "building up" a structural component by welding or riveting, he starts with a solid billet of metal and uses a milling machine to carve the required shape out of it.

For Concorde, the process offered two important advantages: structural integrity and weight-saving. The technique is sometimes known as integral milling and it was the promise it held out of increased strength that first attracted the interest of production engineers. Any joint or weld is a source of possible weakness, and an assembly that has no joints or welds will be potentially that much the stronger. So the process is well suited for producing Concorde components that are highly stressed, like the wing or fin, or in which there are "cut-outs", like the window panels.

Weight-saving, the second advantage, is entirely due to the fact that, correctly programmed, the tape-controlled machine tool can produce a component to closer tolerances than are possible by traditional methods. On the Concorde structure as a whole, savings which amount to some hundreds of pounds have been made in this way. A saving of "some hundreds of pounds" may not sound impressive, but structure weight is a critical factor in the design of an economic supersonic transport. Every additional pound of structure weight in the Concorde requires about an additional pound of fuel to carry it across the Atlantic, and that extra pound of fuel will, in turn, need a second pound of fuel to carry it. Every pound of structure that can be saved, therefore, means a saving of three pounds in take-off weight - which explains why Concorde designers are more weight-conscious than the most ardent slimmer.

The double "learning curve"

In the past, the Concorde manufacturing organisation, and in particular the provision of two separate final assembly lines, one at Filton and the other at Toulouse, has been the subject of adverse comment. Duplication of assembly lines could not be avoided in 1962 however, because it would not have been politically acceptable to have all Concordes assembled in one country. Most outside criticism is not, however, directed at the right target - which is the duplication of the "learning curve", a term that needs a little explanation.

When series production of a new engineering product is begun, everyone concerned has to "learn" how to do his new job. There will be machines to set up, new machining processes to be mastered, jobs to be timed and rates to be fixed. Machinists, fitters, inspectors, supervisors will be feeling their way, and the whole exercise has to be carefully "run in" like a new car.

All this takes time, and, on the production line, time spells money. The first new products off the line, whether they be aeroplanes or washing machines, will cost much more to produce than the price at which they will be sold. That price is based on the assumption that as the workpeople get into the swing of the new job, output will improve and the cost curve will come down steadily until it levels out below the price line. That first downward movement of the curve is called the "learning curve. "

If there are two assembly lines with two lots of people doing the same job, there are obviously going to be two learning curves. To offset the effect of this, BAC and Aerospatiale have made a new approach to aircraft assembly. Up to now, airframe components have been put together on the final assembly jig to form a shell structure, and then all the aircraft systems have been laboriously installed in the shell. In Concorde assembly, much of the work of installing systems is done at the component build stage and the components come, fully equipped, to the final assembly line. This cuts down the work of final assembly and moves much of the learning curve out to the sub-assembly where there is no duplication.

One example of such a fully-equipped component is the nose and forward fuselage built at Weybridge, a 50ft.-long section comprising the flight deck, the forward part of the passenger cabin and the nose landing gear bay. When this component is delivered to the final assembly lines, it is equipped with its cabin insulation and the relevant segments of the electrical, hydraulic, flying control and air-conditioning systems, incorporating 25,000 parts and 90 miles of wiring.

Although the basic structural material used in Concorde is an aluminium alloy, titanium and stainless steel are employed in local areas of high stress and high temperature such as the engine bays. Valuable experience has been gained in working with these metals of the future and advanced manufacturing methods have been developed for dealing with the special problems they present.

In aircraft production welding of titanium has proved extremely difficult in the past because the welding heat source, or beam, has to be directed with pinpoint accuracy on to the weld if the strength characteristics of the surrounding metal are not to be adversely affected. Electron beam welding provides this standard of accuracy, and BAC Filton now has one of Europe's largest electron beam welding chambers. Titanium components can now be satisfactorily built up by welding, allowing smaller billets to be used and thus saving considerable production cost.

Even more advanced laser beam processes are under development. At Filton a special department is engaged on testing and developing advanced manufacturing processes with the object of saving weight and cost and improving product quality. New methods of producing intricate component shapes, such as explosive forming and chemical etching, have been adopted and adapted to the special needs of Concorde.

Aeronautical engineering is acknowledged to be the spearhead of advanced technology. The challenge of measuring up to the new demands of a project like Concorde is a spur to progress in associated industries. New manufacturing methods and new machine tools are part of the response to the Concorde challenge.

Government fears

The Concorde development history can be regarded as falling into three phases: one from the preliminary design stage in 196i 62 to the cutting of the first metal for the prototypes in April, 1965; two, from April, 1965 to the first flight of 01, the first pre-production aircraft in December, 1971; and three from December, 1971 to entry into airline service around the end of 1975.

The second phase getting the plane into the air began in a general atmosphere of uncertainty and, in some quarters, of gloom and despondency, in sharp contrast to the euphoria felt a few months earlier. At some levels on the project, there were strained relations between British and French, in the aftermath of the crisis of confidence caused by the "review" of the project made by the Labour government when it took office in October 1964.

They had announced that they wanted urgently to examine, with the French government, the development programme for Concorde. The French government agreed, but made it clear they were not prepared to countenance any suggestion that Concorde should be cancelled. The November 1962 treaty contained no termination clause. Either directly or indirectly, the French let it be known that any unilateral decision to cancel by the British would be contested in the International Court of Justice at the Hague. In February 1965 the British government announced that they intended to continue with the project in accordance with the terms of the 1962 treaty.

Those four months of uncertainty, however, had a traumatic effect on morale in BAC factories engaged on Concorde design and production. Work went on and there were close contacts with the French at working level, but there was an air of unreality about the daily activities. When the decision to proceed was announced, there was relief but also a sense that government support was something less than wholehearted. Many people working on the project were left with the impression that the final fate of Concorde was likely to depend as much on politics as on its design and performance.

At this time it was accepted that the prototype design, now frozen for manufacture, was an interim design; it was not going to provide the payload-range capability that airlines demanded. Nevertheless, work went ahead because this was an utterly new breed of commercial aircraft and getting a plane into the air and gradually exploring the flight envelope was the only real way to know that the design worked. Maybe the production standard Concorde, when it emerged, would be different from the prototype, but the prototype would establish whether the basic design was right.

Meantime, the dialogue between the makers and the airlines continued, and always the pressure from the operators was for more payload. The design presented to the IATA technical committee in May, 1964 had been a 118-seater. A year later airlines were informed that a modified design was now being offered, with a seating capacity of 139 seats at a 34in seating pitch and a take-off weight of 340,OOOlb. This became known as the "pre-production" aircraft.

To obtain this 18 per cent increase m seating accommodation, the fuselage had been lengthened by about 6ft. 6in. and the rear pressure bulkhead had been moved aft by 15ft. 8in., so increasing the length of the pressurised cabin by l9ft. 3in. The rear ventral door of the prototypes was replaced by two lateral doors at the rear of the cabin, the left side door being for passenger access and the right side door for ground servicing access. A total volumetric payload of 28,0001b. was offered, compared with the 23,6001b. of the prototype.

There was no increase in wing area from the prototype standard, but the results of the intensive aerodynamic research that had been going on showed themselves in subtle re-shaping of the wing tip areas and other refinements. These changes gave the pre-production aircraft's improved performance and operating economics.

Airline reaction to this larger aircraft was much more favourable. Over the next two years a number of new airline names were added to the Concorde options list: Japan Air Lines (three aircraft), Sabena (two), Eastern Airlines (six), Braniff (three), United Airlines (six), Air Canada (four), Lufthansa (three). By mid-1967, 16 airlines had taken a total of 74 Concorde options.

The American SST

All these airlines had also taken options on the American SST, as had many other operators including the British and French flag carriers, BOAC and Air France. The American options total was nearly twice as large as Concorde's, and the list included the names of several prominent operators who had not taken Concorde options.

This point did not go unnoticed. Even among those who were well-disposed towards Concorde, fears were expressed that once again the pioneering would be done on one side of the Atlantic and the exploitation on the other. Those of this school of thought conceded that Concorde would be first into service but they asked: "Won't it soon be overtaken by the larger and faster American type? Isn't this the reasoning that has decided some very experienced operators to ignore Concorde and wait for the 2707?" There was a recent precedent - the Comet and the 707 - that gave some weight to these views, but the two situations were very different. Concorde would have a substantial lead over the American aircraft in getting into service and at the worst (from the European viewpoint) this lead would be four or five years. That was too long a time for any major airline to stay uncompetitive by keeping out of supersonic operation. Unlike the Comet, Concorde would have a non-stop Transatlantic capability and would carry an economic payload. Most important of all, the productivity of the two SSTs would be so different that, when both were in service, they would each fit into a niche that the other could not fill.

Concorde would have four or five years to prove its time-saving attractions and its profitability - and to make the business traveller "supersonic-minded." When the 2707 entered service on the crack routes, Concorde would be operated on the many less densely-trafficked, but still important, routes on which the larger American aircraft would not be viable. There would be a place and a need for the two types as far ahead as one could see.

In the interval, the options arrangements had one great and lasting benefit for the Concorde manufacturers. Option-holding airlines seized the opportunity to take an active part in shaping the design. First into the field were the original three option holders, Pan American, BOAC and Air France. They set up a technical committee - speedily nicknamed the "Troika" - to maintain liaison with the builders. All 16 American option-holders also formed a committee under the chairmanship of William Mentzer, president of United Airlines.

This was something without precedent in the civil aircraft business. Previously it had not been unusual for one or two major airlines to be associated with the development of an air transport design, and indeed the sales of some new types had been hampered by being too closely tailored to the specific needs of a single operator. BAC and Aerospatiale could, and did, count themselves fortunate to have the advice and the constructive criticism of major airlines - making up between them a good cross section of the international air transport market. Their co-operation was invaluable in such areas as performance and economics, noise, interior layout, product support, ground handling and servicing, and maintainability and reliability.

In parallel with design work for the pre-production aircraft, building of the two prototypes, 001 at Toulouse and 002 at Filton, was going forward, although not as rapidly as had been hoped when the programme began in 1965. Some of the problems arose from the fact that this kind of Anglo-French manufacturing collaboration was something new and needed a period for "bedding down." In a sense, the programme was a prototype and a forerunner of better things to come just as the aircraft was. A great part of the delay was also caused by difficulties in getting on-time delivery of equipment and components from outside suppliers, although this was only to be expected, for many suppliers had to mount their own extensive research programmes to develop their products up to the higher standards demanded by the Concorde operational requirement.

Airborne at last

Nevertheless, on a bitterly cold morning in December 1967, the first prototype, 001, was rolled out from its assembly hall at Toulouse. This first public appearance of the aeroplane was intended, through the medium of TV, newspapers and magazines, to give the world, and in particular the French and British taxpayers, a chance to see Concorde "in the flesh," and in this it was undoubtedly successful. But there was still much work to be done on the aircraft and months of painstaking checks and ground testing were to pass before the Western world's first supersonic transport was ready to make its maiden flight.

From the stage of first cutting metal, it had taken nearly four years to get 001 airborne, a long time admittedly, but taking into account the manifold problems in this new field and the fact that the prototypes were being built, as the production engineers put it, "from the floor up," this was no mean achievement.

Sunday, March 2, 1969 was an emotional day for the men who had planned and built the Concorde. On this first flight, Concorde 001 carried the hopes and aspirations of thousands of people who had contributed to the most ambitious technological project in Europe's history. Airline guests and hundreds of journalists from all over the world had gathered in Toulouse for the occasion. TV cameramen and commentators waited to transmit the flight to millions of viewers throughout Europe and the other five continents.

The flight had had to be postponed the previous day because of heavy mist. On the Sunday morning the mist seemed as heavy dank and chill as ever. But the meteorologists and the pilot of the Mirage chase plane who took off to report on conditions "up above" were confident that the sun was going to win this time.

And soon it did. Loudspeakers informed the waiting crowd that Concorde's crew were aboard and pre-flight checks in progress. One by one, the four Olympus engines came to life. Fire tenders and rescue vehicles moved into position. Special trucks, fitted with raucous klaxons, raced up and down the runway, scaring away great flocks of birds. The aircraft moved down the perimeter track and turned slowly to line up on the runway.

For what seemed an age the engines rumbled on. Then came a crescendo of sound, and, brakes released, the white aircraft on its tall undercarriage started to move along the runway, slowly at first but gathering speed. A lot of breath was held, a lot of fists tightly clenched. The nose lifted and there was daylight under the nose wheel.

"She flies, she flies." Millions of television viewers in Britain heard commentator Raymond Baxter's excited shout. In cold blood there may seem something faintly ridiculous about his choice of words - what was Concorde meant to do but fly - but at Toulouse that morning there were not many cold-blooded onlookers.

The crowd watched as she climbed into the blue sky, trailed by her attendant Mirage. Twin plumes of dark smoke marked her passage. She dwindled to a white spot and then was gone. People looked at each other and said trite things to mask the fact that they were deeply moved. It was a short flight, only 40 minutes, but it gave Andre Turcat and his crew a foretaste of what flying a Concorde would be like. Afterwards he was to report that the aircraft handled better than the simulator had predicted.

Over on the grandstand the journalists were in touch with the control tower and received word when 001 was on the approach. She came into view and for the first time, they saw that characteristic "sea-bird" swoop in to land A puff of smoke told that the main bogies were in contact with the runway, the nose-wheel came down, reverse thrust was engaged and the tail parachute broke from its housing to balloon out behind the aircraft.

Safely down! Around the airfield there was a rattle of clapping and applause. Everywhere there were wide smiles of relief There were lumps in some throats and tears in some eyes, including those of experienced journalists who one would have thought had "seen everything."

"Zero-zero-un" taxied to a halt in front of the airport building and passenger stairs were run into position. Within a few minutes the tall figure of Turcat appeared at the top of the steps, followed by his crew. From the crowded terraces there was a roar of cheers and shouts of "ChieŁ" Andre Turcat looked up and waved briefly to his wife on the airport balcony and then went down to accept smilingly the embraces and the handshakes of the Concorde leaders waiting to congratulate him.

The turn of 002

The first flight of the British-assembled 002 took place on April 9, 1969. Around the airfield at Filton, Bristol, were the same big crowds and, once again, hundreds of newsmen there to tell the world about it. After taking off from Filton, 002, had to land at the RAF station at Fairford, Glos., 50 miles to the north-east, as the factory runway at Filton is less than 9,OOOft. Iong, too short for test flying of Concorde.

As with 001 there was much the same feeling of tension as the pre-flight preparations were made, and much the same emotion as the aircraft raced along the runway and soared into the air. When it landed at Fairford, there were more congratulations, more interviews, more smiles.

Two public occasions, two great days. They had come and gone, and among the flight development teams the feeling was: "We have achieved what the public had every right to expect from us - now we can get on with the job of proving the aeroplane."