~~CONCORDE~~

The Aérospatiale-BAC Concorde supersonic transport (SST) was the more successful of the only two supersonic passenger airliners to have ever operated commercially (the Tupolev Tu-144 being the other).

The development programme was a product of an Anglo-French government treaty, with 20 aircraft built. The costly development phase thus represented a substantial economic loss. Air France and British Airways were subsidised to buy the aircraft by their governments, while other sales were blocked by the 1973 oil crisis and competition from the Boeing 747. However, overall, Concorde made very large operating profits for British Airways.

First flown in 1969, piloted by Andre Turcat, Concorde service commenced in 1976 and continued for 27 years. It flew regular transatlantic flights from London Heathrow (British Airways) and Paris Charles de Gaulle (Air France) to New York JFK and Washington Dulles, flying these routes at record speeds, in under half the time of other airliners. Concorde also set many other records, including the official FAI "Westbound Around The World" and "Eastbound Around the World" world air speed records.

As a result of the type's only crash on 25 July 2000, world economic effects arising from the 9/11 attacks, and other factors, operations ceased on 24 October 2003. The last "retirement" flight occurred on 26 November that year.

Concorde remains an icon of aviation history, and has acquired an unusual nomenclature for an aircraft. In common usage in the United Kingdom, the type is known as "Concorde" rather than "the Concorde" or "a Concorde".

THE DROOPING NOSE

Concorde's famous drooping nose was a compromise between the need for a streamlined design to reduce drag and increase aerodynamic efficiency in flight and the need for the pilot to see properly during taxi, takeoff, and landing operations. A delta-wing aircraft takes off and lands with a high angle of attack (a high nose angle) compared to subsonic aircraft, due to the way the delta wing generates lift. The pointed nose would obstruct the pilots' view of taxiways and runways, so Concorde's nose was designed to allow for different positioning for different operations. The droop nose was accompanied by a moving visor that was retracted into the nose prior to the nose being lowered. When the nose was raised back to horizontal, the visor was raised ahead of the front cockpit windscreen for aerodynamic streamlining in flight.

A controller in the cockpit allowed the visor to be retracted and the nose to be lowered to 5° below the standard horizontal position for taxiing and takeoff. Following takeoff and after clearing the airport, the nose and visor were raised. Shortly before landing, the visor was again retracted and the nose lowered to 12.5° below horizontal for maximum visibility. Upon landing, the nose was quickly raised to the five-degree position to avoid the possibility of damage. On rare occasions, the aircraft could take off with the nose fully down.

A final possible position had the visor retracted into the nose but the nose in the standard horizontal position. This setup was used for cleaning the windscreen and for short subsonic flights.

The two prototype Concordes had two fixed "glass holes" on their retractable visors.

source: wikipedia