The BAC Aerospatiale Concorde

Say the word Concorde and most who can remember will conjure up images of that marvel of aviation technology that took travelers hurtling through the stratosphere at twice the speed of sound. Here we are, well into the 21st Century and that era has come and now seems to have gone again. So what was the Super Sonic Transport (SST) Concorde? What was its story? 

To find this out, we need to go back over half a century to the 1950s. The Second World War was still fresh in the minds of most of the world and as with most wars, leaps forward had been made in many technologies. Aviation was certainly one of those technologies. The jet age had begun and imaginations were fuelled by new possibilities that could be realized. 

Concorde History 

The beginning of the Concorde project, although of course, Concorde was a name not yet even dreamt of, rather it was seen as the Super Sonic Transport (SST) project, had its beginnings when Arnold Hall the then Director of the Royal Aircraft Establishment (RAE) asked Morien Morgan to head up a committee to study the possibilities of SST.  They first met in February of 1954 and delivered their findings in April of the following year. Their findings were, that to achieve supersonic speeds and cater to the high amounts of drag at such speeds the wings would have to be short and rectangular, much like those found on missiles and some fighter jets like the Starfighter. At lower speeds, the wings would not be very efficient and would require much longer runways or much more powerful engines. The landing speeds would be eye wateringly fast. The committee, therefore, determined that the SST concept was not feasible. 

Not too long after this finding, Dietrich Küchemann and Johanna Weber of the RAE published papers on the concept of a delta wing. They maintained that the vortices that formed over the upper surface of the wing at high angles of attack, as in during take-off and landing when the aircraft is flying at low speed, created a low-pressure area over the wing which aided in giving the wing the required lift at more acceptable speeds. This effect had been noticed before, notably by Chuck Yeager when flying the Convair XF-92, but never really studied in detail.  To make use of this effect, the aircraft would be required to land and take off with a very high angle of attack, which is with its nose pointed very high above the horizontal. This, in turn, would require much longer landing gear struts so that the tail didn’t slam into the ground. Nevertheless, they were onto something. 

The Delta was the design to go with, but that led to further research required about how to control the center of gravity and the center of lift.  Trials were made with a straight leading edge, a Gothic leading edge where the leading edge curved outwards, and an ogival or ogee leading edge where the leading edge curved inwards. The ogee was the one that produced the right results that would be usable on the SST. 

The heat was another factor that required serious consideration. Moving through the air at the speeds that were proposed causes massive amounts of friction, even in the thinner air of high altitude. Tests showed that aluminum could withstand sustained temperatures of up to 127C over the projected 45,000 hours that Concorde was expected to fly in its life. The decision was made to go with aluminum rather than try and develop a higher temperature capable alloy which could further hold up development. This decision meant that Concorde’s top operating speed would be held to Mach 2.2.  To further manage the skin temperature, a special white paint was used to reduce the temperature by around 6 – 11C. To illustrate the difference. One Concorde was painted in Pepsi colors (blue) for a promotion around the Middle East. During this time, this Concorde could only fly Mach 2.2 for periods of 20 minutes, it then had to drop back to a maximum of Mach 1.7.  Fuel was also used as a heat sink by being pumped to heat affected areas and using the residual heat to aid the cabin heating. Of course, when things heat up they expand. During the cruise, Concorde’s fuselage would grow by nearly 30cm (1 foot). 

This was most noticeable at the flight engineer’s workstation where the panel would separate from the bulkhead. It is said that during the last supersonic of each Concorde the flight engineer dropped his hat into the space and on descending the hat would be permanently encased as the space closed up again. 

Radiation was another factor that had to be considered due to the high cruise altitude.

At altitudes around 50,000’ to 60,000′, the atmosphere is very thin and the protective layers between the passengers and the sun were severely reduced compared to our normal ground-dwelling environment.  Skin cancer was a real concern and to this end, a radiometer that measured radiation was installed in the cockpit. During high sunspot activity, if the readings became too high, Concorde could be descended to a safer altitude below 47,000’. 

Concorde 

The French were also pursuing the SST concept and their government asked for designs to be provided by their own Sud Aviation and Nord Aviation as well as Dassault. Strangely enough, all three came back with designs based on the Dietrich Küchemann and Johanna Weber slender delta design.  Sud Aviation was chosen and in April 1960 Pierre Satre the company technical director flew to Bristol to seek a partnership.  There was some surprise in Bristol that the French design was so close to their own.  It turns out that some details of the English design had been leaked to the French.  More than likely a little sweetener as Britain was trying to enter the European Economic Community (EEC) or Common Market as it was known. The main barrier to Britain joining the EEC was France or more particularly President Charles de Gaulle of France.

Both parties agreed on most points, other than the French wanting a smaller version whilst the British were looking for a 150-seat version for the North Atlantic.  At first, it was thought the larger British version would require 6 engines whilst the French smaller version could be operated with 4 engines. This was solved by the development of the Bristol Siddeley Olympus which provided enough power to enable both options with 4 engines.  There was much debate around the pros and cons of the economics of the project, however, the one big factor was the fear of not coming first to market and therefore missing out on the expected boom expected for the SST space. 

This was more of a national collaboration than a partnership between two companies. A draft treaty was signed on 29 November 1962. The name Concorde was chosen as in French it means agreement, harmony, or union, as does the English version concord. There was consternation in England at the use of a French word but the then Minister of Technology, Tony Benn was quick to point out the “e” stood for England and excellence. It was changed to Concord but then later back to Concorde. Not the Concorde or a Concorde but just Concorde like it was someone’s name. 

Concorde Sales 

Concorde was seen as a most ambitious undertaking if not a flawed one.  The development costs spiraled out of sight. Other factors also added fuel to the fire burning the platform from under the Concorde project such as the 1973 oil crisis followed by the 1973/74 stock market crash. The aviation scene was also changing. Aircraft such as the Boeing 747 and the McDonnell Douglas DC-10 were setting a new trend for lower airfares. This had not been factored into the SST equation. The sonic boom was a problem as it caused problems flying over populated areas, as was the pollution. The final straw for many airlines was the break-up of the Russian Tupolev TU-144 (dubbed Conkordski) over the Le Bourget Paris air show of 1973.

It caused a lack of faith in the new technology. At the time of the first flight of Concorde, 16 airlines had penciled in 74 airframes. BOAC (British Overseas Airways Corporation, forerunner of British Airways) and Air France were the only airlines to take up their orders. 

The airlines that placed orders are shown below in order of the date they signed for the option to take Concorde.

In all, 20 Concordes were built. 

• 2 x Prototypes 
• 2 x pre-production aircraft 
• 2  x development aircraft 
• 14 x production aircraft. 

Concorde Prototypes 

Two prototypes were built as quickly as possible to prove that the theories about SST were correct. One was French and one British. The first to fly was the French Concorde, airframe 001, which took place from Toulouse on 02 March 1969. The aircraft flew 812 hours of which 255 were supersonic. In 1973 Concorde 001 was modified with rooftop port holes to enable her to be used for the observation of a solar eclipse over Africa. It was the longest observation of a solar eclipse at 74 minutes. She was retired to the French Air Museum at le Bourget on 19 October 1973 after 397 flights. 

The British prototype made its first flight on 09 April 1969 from Filton to RAF Fairford. After completing 438 flights for a total of 836 hours of which 196 were supersonic, Concorde 002 made her last flight on 04 March 1976. She was retired to the Fleet Air Museum at RAF Yeovilton. 

Concorde Pre-production Aircraft 

With the lessons learned from the prototypes, modifications were made to the design. The wing design was modified, and more fuel capacity was added as well as improvements to the engine air intake design. 

Concorde Production Aircraft. 

Two production aircraft, 201/202, were built. These aircraft contained all the modifications required as a result of the strenuous testing of the prototypes and pre-production aircraft. These airframes were a representation of the finished product that would be rolled out to customers. Their purpose was to be used to gain certification of the type.

Following certification, 14 more production aircraft were built, 7 each for Air France and British Airways. 

Concorde Specs

The Concorde as we can see was a one-off design. Other than the Tupolev TU-144 “Conkordski” which flew briefly on some internal routes in Russia, Concorde was the only SST (SuperSonic Transport) to make it off the drawing board and into the history books as a marvel of aviation. Below we can get an idea of what made Concorde what it was and how it measured up.

Air France Flight 4590 – The Beginning of the End. 

At 16:43 on 25 July 2000, Air France’s first received Concorde F-BSTC sealed her fate as well as that of Concorde as a type, when she ran over some debris on the runway at Charles de Gaulle airport, Paris. Flying under a special flight number, AF 4590, she was on a charter flight from Paris to JFK, New York. Chartered by a German company, Peter Deilmann Cruises, the 100 passengers were to join their cruise ship, MS Deutschland, for a 16-day cruise to Manta, Ecuador. 

It is alleged that a Continental Airlines DC-10 bound for Newark, New Jersey 5 minutes before Concorde dropped a strip of titanium on the runway. Concorde ran over this on its take-off run which caused a tire to be cut. Tyre debris was flung into the underside of the wing, not puncturing it but causing a shock wave that ruptured the number five fuel tank at its weakest point, just above the landing gear.  The resultant gush of fuel either touched a hot part of the engine or was sparked by a wire that was parted by the debris. Engines 1 and 2 both surged then lost power. Engine 1 slowly recovered. Engine 2 was shut down by the engineer on command by the captain.  

Air traffic control noticed flames coming from under the wing and informed Concorde. The aircraft had passed V1 and the captain decided to continue the takeoff.  After lift-off, the crew was unable to close the landing gear bay door.  This coupled with the reduced thrust of only 3 engines prevented the aircraft from being able to climb. The heat of the fire on the port wing caused it to start disintegrating as the metal started to melt.  Once again Engine 1 surged and this time lost thrust never to recover again. The asymmetric thrust caused by 2 engines operating on one side and none of the other made the aircraft uncontrollable. It banked to 100 degrees and the crew reduced power to try and compensate. The result was the aircraft slowed further and reduced speed made the aircraft stall. The aircraft crashed into the Hôtelissimo Les Relais Bleus near the airfield.  According to cockpit transcripts the crew was hoping to divert to le Bourget airfield. 100 passengers and 9 crew were lost on the aircraft as well as 4 employees from the hotel perished. 

All Concordes were grounded shortly after the crash pending further investigation. Once the cause was known, £17M of safety modifications were made to most of the Concordes and services resumed on 01 November 2001. Finally, all aircraft were retired in 2003. 

The heady days of supersonic flight were over and the pride of the French and British aviation industry was sent to various museums and displays to be enjoyed and marveled at by future generations. 

Source: https://modernairliners.com/concorde-plane/