Concorde.

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 Concorde Delta wing with the ogival or ogee leading edge made it possible to land and take off at acceptable speeds as well as control the centre of lift and gravity.

The Delta wing was definitely the design to go with, but that led to further research required about how to control the centre of gravity and the centre 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. 

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 aluminium 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 aluminium 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.

The high angle of attack required by the delta wing for take-offs and landings required longer undercarriage to avoid the tail hitting the ground. A ram was placed under the tail cone for just such an eventuality.

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 colours (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 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 flight 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.

Concorde in Pepsi colours for a promotion in the Middle East in 1996 at Dubai. In the darker colours Concorde could only fly at Mach 2.2 for 20 minutes and then had to drop down to Mach 1.7 due to skin temperature heating.

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

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’.

Air France Concorde registration F-BVFC.

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's 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.

Air France Concorde Fake Afterburner registration F-BVFF.

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 in the SST space.

British Airways Concorde Post card.

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 that 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. 

British Airways Concorde G-BOAD at London Heathrow (LHR) 15MAY2003.

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 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.

This Air France Concorde landing clearly shows how the nose of Concorde is dropped during take-off and landing to enable pilots to have a better view forward. During cruise, the nose is raised and screens are raised over the forward windows to create a smooth airflow.

The Concorde tail bumper wheel as seen here on British Airways G-BOAD was designed to take the hit in case the pilot overcooked the rotation on take-off or landing.

In all, 20 Concordes were built. 

• 2 x Prototypes 

• 2 x pre-production aircraft 

• 2  x development aircraft 

• 14 x production aircraft. 

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.

British Airways Concorde G-BOAC.

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.

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.

Concorde Interior British Airways registration BOAG.

A detailed list of all Concordes built.

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 German company, Peter Deilmann Cruises, the 100 passengers were to join their cruise ship, MS Deutschland, for a 16-day cruise to Manta, Ecuador. 

At the Technikmuseum, Sinsheim, Germany a celebration of the brief but heady days of Supersonic Passenger Travel. Concorde and Tuplolev TU144 fly together.

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 tyre 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 and then lost power. Engine 1 slowly recovered. Engine 2 was shut down by the engineer on command by the captain.

The BAC Concorde on show at Yeovilton nicely shows off how Concorde looked in cruise. The nose is in the up position and the cockpit forward window cover is in place.

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 the lift-off, the crew were 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 the 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. 

The Tupolev TU144 or “Conkordski” as it was affectionately dubbed, had much the same design as the Concorde. The TU144 did sport a pair of canards behind the cockpit to enable nose up and down control at slower speeds. These folded away into the fuselage when not used.

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 marvelled at by future generations. 

Air France's Concordes were run at a loss but maintained as a matter of national pride. British Airways, on the other hand, managed to run theirs at a profit of an average of GBP30M per year.  

Maybe one day we will see the return of supersonic flight, however, it seems more likely that shooting ships into low orbit to reach their destinations in very fast times may be the future of fast travel.