AERONAUTICS

supersonic civil aircraft

An Air France Concorde landing at Kansai International Airport in Japan in 1994. © Spaceaero2 / Wikimedia Commons

Text by: Nenad Tomic

9 mins

When we think of supersonic civil aircraft, the first thought is obviously for the famous Concorde, this incredible aircraft built by the French and the British that can reach almost twice the speed of sound.

But there is also another supersonic aircraft built by the Soviets: the Tupolev 144. Presented at the same time as the Concorde, with almost similar lines and performance, these two magnificent machines are the symbols of the Cold War and the race towards the advanced technology of the two blocks.

While the Tupolev 144 ended its career after a few years and only 55 official civil flights, the Concorde marked the world of aviation for almost four decades.

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The birth of the civilian supersonic

At the end of the 1950s, the context of the Cold War provoked a real technological competition between the Western powers and the Soviets.

In addition to the arms race and the conquest of space, the project to build a civil aircraft that would transport passengers at the speed greater than that of sound becomes obvious.

Like military combat aircraft, which already at that time could reach a top speed of 2 Mach (unit of measurement of aircraft speed), i.e. twice that of sound, the new supersonic aircraft must maintain this speed constantly.

Engineers are then faced with a challenge to exceed the performance of civil jet aircraft and create a new safe and comfortable aircraft, capable of reducing the time of a flight by half.

The French aeronautical companies Sud-Aviation (the ancestor of Airbus) and the British Bristol Airplane Company are each developing the project of a supersonic aircraft.

But the costs are exorbitant, which leads the French and British governments to have the two companies collaborate to work on a single project: that of Concorde.

The international cooperation treaty between the two countries was signed on November 29, 1962. To develop the turbojet capable of flying at very high speeds, two large companies were responsible for it: Bristol Aero Engines, which was bought by Rolls- Royce shortly after, then the French Snecma.

It took almost seven years to finally see the first flight of Concorde with the prototype called 001. On March 2, 1969, the first supersonic aircraft made its first test flight above the Toulouse region.

But the device does not reach the speed of sound on this occasion.

After several flights and public demonstrations with this first model, it was in 1972 that the second prototype 002 performed several flights and aroused genuine interest in this type of aircraft all over the world.

Sixteen major airlines are rushing to place the order.

Unfortunately for the Concorde, the first oil shock in 1973 forced most companies to cancel orders.

Only Air France and British Airways will ultimately buy the sixteen aircraft that left the factory.

They operated them from 1976 until Concorde was retired in 2003.

Technical prowess

The Concorde included so many technical innovations that we find even today in airliners.

For the first time, a civilian aircraft has fully electric flight controls, because those by cables are incompatible with the very elongated fuselage shape of the Concorde.

Likewise, it is the first time that an autopilot device has made it possible to control the aircraft without having to touch the controls.

Finally, the various hydraulic circuits, and in particular the braking circuit, complete the picture.

The fuselage of the Concorde, very elongated with set-back delta wings, also requires perfect weight management in order to maintain the balance of the aircraft in full flight.

Apart from the distribution of masses related to passengers and baggage, it is the weight of the fuel transported in large quantities that had to be carefully positioned around the aircraft's center of gravity.

Thus, during the different phases of the flight and according to consumption, the fuel was moved from one tank to another.

A particular exercise entrusted to a member of the crew in the cockpit.

The Concorde has thus become the only plane to transport a hundred passengers in 3h30 between Paris and New York at an altitude of between 16,000 and 18,000 meters, that is to say almost twice as many as airliners " ordinary”.

The case of Tupolev Tu-144

While the French and the British are presenting the Concorde, the Soviets are bringing their workhorse out of the hangars: the Tupolev Tu-144.

It was immediately nicknamed "Concordski" or "Concordoff" by the Western media because of its very strong resemblance to the Concorde.

The first prototype of Tupolev's supersonic made its first test flight on December 31, 1968 in the Moscow region, that is to say two months before Concorde.

It also outstripped its western competitor in crossing the speed of Mach two and it goes down in history as the fastest civilian aircraft in history.

But the design of the Tupolev 144 is greatly helped by the real game of industrial espionage that takes place around the Concorde project.

According to aeronautical specialists, several agents managed to appropriate precise plans of the brake system, the landing gear or the fuselage, hence this remarkable resemblance between the two planes.

However, the Tupolev 144 is not a simple copy of the Concorde, because the Soviet engineers carry out the many changes over the tests and also increase the capacity of the plane to approximately 140 seats.

This Tupolev-144LL, the last to be produced, flew from 1984 to 1986. © Wikimedia Commons

But the fate of the supersonic plane from the East was seriously compromised at the Le Bourget air show on June 3, 1973. During the flight demonstration, the plane crashed in front of thousands of spectators.

The Tupolev 144 was operated solely by the Aeroflot company and was initially used to transport mail and goods between Moscow and Alma-Ata from 1975 to 1977. For only a few months, the company maintained a regular flight between these two cities, but an accident that occurred on May 23, 1978 put an end to the commercial operation of the aircraft, which ultimately only performed 55 flights.

Despite the cessation of flights, Tupolev produced two more aircraft and Aeroflot made a few occasional flights during the 1980s. These airworthy aircraft are also used by scientists who carry out research on the layers of ozone at the edge of the stratosphere.

At the end of the Cold War, in the early 1990s, NASA and Tupolev used the Tu-144 model to relaunch the construction of another model of the civilian supersonic aircraft.

After an investment of more than 300 million dollars and around thirty test flights, the project was finally abandoned in 1999. The last copies of Tu-144 are exhibited in the museums currently located in Zukhovsky in Russia and in Sinsheim, in Germany.

The crash of Concorde and the end of a dream

However, the emblematic Concorde is far from being a perfect aircraft.

Due to the "supersonic boom" it produced when it broke the sound barrier, it could only fly over seas and oceans.

In addition, the noise during the take-off and landing phases was twice as high as that of other commercial aircraft.

Its consumption (four times more than an airliner) and the cost of maintaining the aircraft mean that the flights are loss-making for the companies.

But the beginning of the end of Concorde begins with the accident during takeoff, on July 25, 2000. On the runway of Charles-de-Gaulle airport, the Concorde enters the takeoff phase bound for New York.

A metal blade of a few tens of centimeters which is on the runway (lost by an apparatus which took off just before the Concorde) rushes into the reactor and pierces one of the tanks.

This is the drama.

The legend crashes a few seconds later on a hotel in Gonesse, killing 113 people in total.

The airlines Air France and British Airways finally stopped operating Concorde in 2003, after 27 years of service.

The supersonic future

Ever since Concorde retired, the aviation world has been dreaming of a supersonic successor.

Meanwhile, several projects fail, but the Boom Supersonic company, located in Denver in the American state of Colorado, has a serious project with a brand new device called Overture.

Officially presented at the Farborought show in Great Britain in July 2022, the new aircraft could become the fastest in the world after the glorious era of Concorde.

According to Boom Supersonic, the future aircraft is designed to carry between 60 and 80 passengers at a speed of 1.7 Mach, or 2,100 km/h.

It will therefore not exceed the cruising speed of Concorde (2 Mach) but it will be much more economical, less noisy and above all ecologically neutral because it will use biofuel.

Overture, the new supersonic aircraft built by the Boom Supersonic company (illustration image).

© 2022 Boom Supersonic

According to the first projects unveiled, its design and the latest technologies will reduce the noise of the reactors.

In addition, Florida Turbine Technologies, one of Boom Supersonic's partners, is working on the brand new turbofan engine without afterburner.

This system, used in the engines of Concorde, produced this noise which reached 120 decibels, that is to say the pain threshold for the ear.

The Denver company is making great strides with Overture, as the first tests are scheduled for 2026 and the first flight tests the following year.

The first flights with passengers will be able to take place as early as 2029.

Some major airlines are already interested in having these aircraft in their fleet.

The American company United has ordered 15 aircraft and plans to buy 35 more.

Virgin Atlantic and Japan Airlines have also signed a pre-order of 30 aircraft in all.

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