Engineering series 2: The Concorde

Introduction

In the second part this engineering series we will take a closer look at the supersonic passenger airliner Concorde, which was developed in the mid-20th century in France and Great Britain with much public attention.

For me it seems that this impressive example of modern engineering work sinks more and more into oblivion, not least since the trend for airline passenger transports drifted towards huge and comparatively slow jumbo-jets in the last three decades.

“Let’s visit Airbus”

Three years ago I visited the south of France, including the major city of Toulouse.

Toulouse has a noteworthy history regarding its aviation industry, which can be traced back to the first decades of the 20th century. In Toulouse-Blagnac in the north-west of the city, the headquarters of Airbus and an airport are situated.

Here I spent several hours to marvel at at the two Concorde supersonic airliners exhibited in the aviation museum, which one can find next to the airfields and the production facilities of the A380 passenger airliner.

Concorde in the aviation museum in Toulouse-Blagnac
Concorde F-BVFC in the aviation museum in Toulouse-Blagnac

The last regular flight of a Concorde was in 2003. Due to the low profits, the lack of passenger comfort, the noise level and one major crash three years earlier, commercial operations were completely abandoned in the aftermath.

Almost the whole fleet (which comprises not more than about a dozen planes) is now exposition object in Europe or the USA, and will in all likelihood never take off again.

Development history

Supersonic military aircraft exist since the end-phases of 2nd World War.

The first feasibility analyses for civil use were carried out during the 1950s in Western Europe, similar efforts were made in the Soviet Union (which led to the eventually built Tu-144) and the USA (which led to the Boeing 2707 project) during the 1960s.

The big airplane-manufacturers were interested in such an aircraft, because oil was comparatively cheap at the time (until the first oil-crisis emerged in the 1970s), and the public was yet not particularly concerned about environmental issues like emissions or noise level.

Concorde instrument panel, aviation museum in Toulouse-Blagnac
One of the instrument-panels of F-WTSB

The financial risks of such a project were immense nonetheless. One single national airline company in Europe wasn’t capable to carry out the whole development on its own.

Therefore, a cooperation-agreement between France’s and Great Britain’s state-owned airlines was made in 1960, which led to the eventual name of the prestige-project: Concorde (French for “unity”).

Technical overview

The design of a supersonic aircraft was due to technical considerations in many respects predetermined.

Physical constraints led to very similar wing-shape and fuselage of the Concorde and the Soviet Tu-144, though the latter had for instance so-called canards (French for “duck-wings”) as low-speed stabilizer mechanism, and an entirely different propulsion-system.

Propagation of sound waves at Mach number 1, the aircraft is as fast as the sound-waves it emits

The characteristic of a supersonic flight is a Mach-number exceeding 1.

This number describes exactly the ratio between the object velocity, and the speed of sound in that fluid (air in the case of an airplane).

If the object-velocity exceeds this speed, a sonic boom is generated and dragged through the aircraft (because of this the Concorde flew very seldom with supersonic speed across the continent, but as scheduled flight across the Atlantic Ocean).

Propagation of sound waves with Mach number >1, the aircraft is faster than the sound-waves it emits

The triangle-shaped delta wings similar to military aircraft or the Space Shuttle had been the most salient feature of the Concorde, since conventional wing-shapes are inapplicable for supersonic speed.

Due to high friction, that means more precisely higher exposure to heat within high-velocity ranges, special materials and alloys were used for fuselage and wings.

Concorde crash in 2000

After decades of service without any major incidents, a crash in July of 2000 caused the death of about one hundred people, for the most part German tourists on their way to New York.

The majority of airplane crash-landings can be traced to an initial cause, which coincides and links with other irregularities (which can directly or indirectly be triggered by this cause).

Air France Flight 4590
Air France Flight 4590

In the given case it was a lost metal strip of a DC-10 airliner on the runway. The metal strip lacerated one of the tires, and a few rubber-fragments were blasted towards the wings with its kerosene supply system.

This caused a compression wave within the system that ruptured the structure, and as bad luck had it the kerosene was ignited by torn electric wiring immediately.

Due to the heavy structural damage, the aircraft got uncontrollable seconds after the take-off and crashed onto a nearby hotel.

Poor design of the tires and negligently carried-out maintenance contributed to this fatal disaster.

It was the next to last factor to close down commercial services completely (the final nail in the coffin were the September 11 attacks) and make exposition objects out of the fleet, since the trend in the last decades was already in favor of big jumbo-jets like the A380.

Sidenote: You can visit the final assembly of the A380 in Toulouse-Blagnac (guided tour of about one hour), required is only a reservation: Let’s visit Airbus

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