CONCORDE:
WONDER OF CIVIL AND COMMERCIAL AVIATION

Text and Photo: José Manuel Serrano Esparza
Le Bourget Airport, Paris, April 21st 2000


©José Manuel Serrano Esparza


Since it began its regular service in 1977, the passenger and comercial supersonic Anglo-French Concorde has proved to be the fastest and luxurious aircraft in the world within its domain.

Its advantages are manifold, because in the modern world to save time means saving money and all the unprofitable hours spent inside other models of planes during the typical business travels, are reduced to the minimum, thanks to its cruise speed of Mach 2 (2,200 km/h).

This way, the route Paris-New York, that usually requires a seven hours flight, is reduced to 3,5 hours.

Travelling inside the Concorde means to minimize the fatigue and reaching the destiny fresh and rested, without the need of recovery, and the traveller can set about the previously planned activity immediately after the landing.

The flexibility and freedom provided by the Concorde have no match and all the passengers who have travelled on it, both because of business or tourism, have stated that it would be very difficult for them to come back to subsonic flights in aircraft of other aviation companies, once they have experienced the effortless travel which the Concorde implies and its huge effectiveness.

The fuselage of the Concorde is almost as long as that one in a normal width passenger aircraft (62,10 m compared with the  67 m in a Boeing 747), but much narrower.

The speed and the aerodynamic shape are very related.

The Concorde designers had to create an aircraft featuring a very aerodynamic profile to mostly ensure the maximum feasible penetration in the atmosphere, even with a top load of 185 tons.

It sports delta wings, the most suitable ones for the supersonic flight, which demands a combination of enough length and span, minimum relative thickness and low profile.

Both the quoted fuselage and the already famous very sharp-pointed satisfy these requirements together with those inherent to the subsonic flight, takeoff and landing, while they boast enough structural rigidity and a very solid system of aerodynamic ascending force. Its stability is such that the Concorde is the only commercial airship not requiring rudders.

Its finishing in a sharp point guarantees top penetration into the air.

Since the nose is much longer than the ones featured by other planes and due to the fact that at the low takeoff and landing speeds, aircraft having delta wings move in a much more pronounced angle with respect to the floor, the engineers had to find a way to provide the crew with clear visibility.

Therefore, and in a spectacular way, the Concorde nose is movable and is lowered both for the takeoff and the landing.

It has also a retractable viewfinder keeping the aerodynamic profile of the jet and protecting the windshield during the flight.

Regarding the thrust, this is one of the scarce moments in which acceleration is really felt and the passenger realizes the great power of the jet, since this is the moment of maximum energy production, with each engine developing a thrust of 17,260 kg.
The strong and steady acceleration makes the plane take off at a speed of 360 km/h in 30 seconds, after running an average distance of 1,500 m.

Approximately ten seconds after the takeoff, you can hear the reintroduction of the landing gear inside the lower part of the aircraft.

A key aspect in the Concorde is the post-combustion. In fact, the driving force with regard to the aircraft weight in the Concorde is 1,66 times bigger than the one in a Boeing 747. It explains the relatively short takeoff time of the Concorde.

This powerful starting driving force comes from a standard jet to which a system of post-combustion has been added up.
The goal of the post-combustion is to reheat the exhausting gases of the jet engine to increase its ejection speed, which in its turn raises the driving force a 17%.
The post-combustion is used for the takeoff and is interrupted by the pilot after 30 seconds, so as to lessen the noise. At this moment, the passenger experiences a light feeling of braking.

During the transition from subsonic to supersonic flight, there´s a change in the aerodynamic center of the Concorde. To make up for it, it was decided to transfer the fuel inside the aircraft (without having to resort to external aerodynamic equipment), in such a way that the fuel is conveyed through a pumping system from the front tanks to the compensation ones located in the back of the fuselage.

On leaving the inhabited areas at Mach 1,7, the captain switches off the post-combustion. Very quickly, the plane reaches Mach 2, that´s to say 2,200 km/h, the cruise speed of the Concorde.

Inside the airship, you hardly realize the Concorde supersonic speed. The passenger is flying double the sound speed without noticing it.

The cruise altitude of the Concorde fluctuates between 16,000 and 18,000 meters.

Unlike other aircraft, the Concorde climbs steadily during the flight. The lack of air traffic at the great height in which the Concorde flies, allows it to choose its optimal altitude, which is increased as the plane becomes lighter due to the fuel consumption.

At these moments, you are already flying inside the stratosphere, an atmospheric layer encompassing from around 10,500 m to 60,000 m on the land surface. At 16,000 metres, the atmospheric pressure is a tenth of the land one and the sky features an intense blue colour, almost purple, the anteroom of outer space.

It´s a very smooth and quiet flight, for in this level of the atmosphere there aren´t any
turbulences.

With conventional jets, the atmospheric turbulences bring about sudden accelerations and low frequency vibrations that can cause sickness, while in this case its absence linked to the narrow delta shaped wings, provide the Concorde with a remarkable stability, bigger comfort and less stress and fatigue for the passenger.

Some powerful air conditioning generators guarantee that the pressure inside the Concorde is equivalent to an altitude of 1,700 m, a full-fledged achievement, if we bear in mind that it is lower than the one present inside the standard subsonic airships sporting an inner pressure equivalent to between 2,000 and 2,500 m.

The previous descent before landing is a part of the flight in which the passenger perceives a
reduction in the power of the engines and a progressive braking.

It´s also the moment in which the fuel is transferred to the front part of the aircraft, returning to subsonic flight.

At the end of the approaching to land previous to the landing, the front part of the Concorde is
tilted 12º down regarding the floor and the Concorde raises its nose in order to land. This is a curious and little frequent fact, since the standard passenger airships take this position only during takeoff.

The Concorde lands at 275 km/h on an air mattress under the wing surface, in the same way as happens with some aquatic birds, with a very powerful progressive deceleration on the airstrip due to the exceptional performance of the braking system.

In the same way as with the vast majority of systems of the aircraft, the brakes of the Concorde
are electronically controlled to attain an optimal performance depending on the state of the airport airstrip: rain, snow, ice, etc.

The Concorde was born from the partnership between two aeronautic firms: the French Aèrospatiale and the British British Aircraft Corporation.


Technical Specifications:
Wingspan: 25,56 m
Surface: 358,25 m
Length: 62,10 m
Width: 2,87 m
Height: 3,33 m
Cruising Range: 6,500 km.


© Copyright Text and Photo: José Manuel Serrano Esparza