Aérospatiale-BAC Concorde (1969)

Aérospatiale-BAC Concorde (1969)

Aérospatiale-BAC Concorde /ˈkɒŋkɔrd/ is a retired turbojet-powered supersonic passenger airliner or supersonic transport (SST). It is one of only two SSTs to have entered commercial service; the other was the Tupolev Tu-144. Concorde was jointly developed and produced by Aérospatiale and the British Aircraft Corporation (BAC) under an Anglo-French treaty. First flown in 1969, Concorde entered service in 1976 and continued commercial flights for 27 years.

Among other destinations, Concorde flew regular transatlantic flights from London Heathrow and Paris-Charles de Gaulle Airport to New York JFK, Washington Dulles and Barbados; it flew these routes in less than half the time of other airliners. With only 20 aircraft built, the development of Concorde was a substantial economic loss; Air France and British Airways also received considerable government subsidies to purchase them. Concorde was retired in 2003 due to a general downturn in the aviation industry after the type’s only crash in 2000, the 9/11 terrorist attacks in 2001, and a decision by Airbus, the successor firm of Aérospatiale and BAC, to discontinue maintenance support.

A total of 20 aircraft were built in France and the United Kingdom; six of these were prototypes and development aircraft. Seven each were delivered to Air France and British Airways. Concorde’s name reflects the development agreement between the United Kingdom and France. In the UK, any or all of the type—unusually for an aircraft—are known simply as "Concorde", without an article. The aircraft is regarded by many people as an aviation icon and an engineering marvel.

Early studies

Concorde

The origins of the Concorde project date to the early 1950s, when Arnold Hall, director of the Royal Aircraft Establishment (RAE) asked Morien Morgan to form a committee to study the SST concept. The group met for the first time in February 1954 and delivered their first report in April 1955.

At the time it was known that the drag at supersonic speeds was strongly related to the span of the wing. This led to the use of very short-span, very thin rectangular wings like those seen on the control surfaces of many missiles, or in aircraft like the Lockheed F-104 Starfighter or the Avro 730 that the team studied. The team outlined a baseline configuration that looked like an enlarged Avro 730, or more interestingly, almost exactly like the Lockheed CL-400 "Suntan" proposal.

This same short span produced very little lift at low speed, which resulted in extremely long takeoff runs and frighteningly high landing speeds. In an SST design, this would have required enormous engine power to lift off from existing runways, and to provide the fuel needed, "some horribly large aeroplanes" resulted. Based on this, the group considered the concept of an SST unfeasible, and instead suggested continued low-level studies into supersonic aerodynamics.

Slender deltas

Soon after, Dietrich Küchemann at the RAE published a series of reports on a new wing planform, known in the UK as the "slender delta" concept. Küchemann’s team, including Eric Maskell and Johanna Weber, worked with the fact that delta wings can produce strong vortexes on their upper surfaces at high angles of attack. The vortex will lower the air pressure and cause lift to be greatly increased. This effect had been noticed earlier, notably by Chuck Yeager in the Convair XF-92, but its qualities had not been fully appreciated. Küchemann suggested that this was no mere curiosity, and the effect could be deliberately used to improve low speed performance.

Küchemann’s papers changed the entire nature of supersonic design almost overnight. Although the delta had already been used on aircraft prior to this point, these designs used planforms that were not much different from a swept wing of the same span. Küchemann noted that the lift from the vortex was increased by the length of the wing it had to operate over, which suggested that the effect would be maximized by extending the wing along the fuselage as far as possible. Such a layout would still have good supersonic performance inherent to the short span, while also offering reasonable takeoff and landing speeds using vortex generation. The only downside to such a design is that the aircraft would have to take off and land very "nose high" in order to generate the required vortex lift, which led to questions about the low speed handling qualities of such a design. It would also need to have long landing gear to produce the required angles while still on the runway.

Küchemann presented the idea at a meeting where Morgan was also present. Eric Brown recalls Morgan’s reaction to the presentation, saying that he immediately seized on it as the solution to the SST problem. Brown considers this moment as being the true birth of the Concorde project.

Design

Concorde is an ogival (also "ogee") delta-winged aircraft with four Olympus engines based on those employed in the RAF’s Avro Vulcan strategic bomber. Concorde was the first airliner to have a (in this case, analogue) fly-by-wire flight-control system; the avionics of Concorde were unique because it was the first commercial aircraft to employ hybrid circuits. The principal designer for the project was Pierre Satre, with Sir Archibald Russell as his deputy.

Concorde pioneered the following technologies:

For high speed and optimisation of flight:

Double delta (ogee/ogival) shaped wings
Variable engine air intake system controlled by digital computers
Supercruise capability
Thrust-by-wire engines, predecessor of today’s FADEC-controlled engines
Droop-nose section for better landing visibility
For weight-saving and enhanced performance:

Mach 2.04 (~2,179 km/h or 1,354 mph) cruising speed for optimum fuel consumption (supersonic drag minimum although turbojet engines are more efficient at higher speed) Fuel consumption at Mach 2.0 and altitude of 60,000 feet was 4,800 gallons per hour.
Mainly aluminium construction for low weight and conventional manufacture (higher speeds would have ruled out aluminium)
Full-regime autopilot and autothrottle allowing "hands off" control of the aircraft from climb out to landing
Fully electrically controlled analogue fly-by-wire flight controls systems
High-pressure hydraulic system of 28 MPa (4,000 lbf/in²) for lighter hydraulic components
Complex Air Data Computer (ADC) for the automated monitoring and transmission of aerodynamic measurements (total pressure, static pressure, angle of attack, side-slip).
Fully electrically controlled analogue brake-by-wire system
Pitch trim by shifting fuel around the fuselage for centre-of-gravity control
Parts made using "sculpture milling", reducing the part count while saving weight and adding strength.
No auxiliary power unit, as Concorde would only visit large airports where ground air start carts are available.

Engines

Concorde’s intake system

Concorde needed to fly long distances to be economically viable; this required high efficiency. Turbofan engines were rejected due to their larger cross-section producing excessive drag. Turbojets were found to be the best choice of engines. The engine used was the twin spool Rolls-Royce/Snecma Olympus 593, a development of the Bristol engine first used for the Avro Vulcan bomber, and developed into an afterburning supersonic variant for the BAC TSR-2 strike bomber. Rolls-Royce’s own engine proposed for the aircraft at the time of Concorde’s initial design was the RB.169.

The aircraft used reheat (afterburners) at takeoff and to pass through the upper transonic regime and to supersonic speeds, between Mach 0.95 and Mach 1.7. The afterburners were switched off at all other times. Due to jet engines being highly inefficient at low speeds, Concorde burned two tonnes of fuel (almost 2% of the maximum fuel load) taxiing to the runway. Fuel used is Jet A-1. Due to the high power produced even with the engines at idle, only the two outer engines were run after landing for easier taxiing.

The intake design for Concorde’s engines was especially critical.[Conventional jet engines can take in air at only around Mach 0.5; therefore the air has to be slowed from the Mach 2.0 airspeed that enters the engine intake. In particular, Concorde needed to control the shock waves that this reduction in speed generates to avoid damage to the engines. This was done by a pair of intake ramps and an auxiliary spill door, whose position moved in-flight to slow transiting air.

Engine failure causes problems on conventional subsonic aircraft; not only does the aircraft lose thrust on that side but the engine creates drag, causing the aircraft to yaw and bank in the direction of the failed engine. If this had happened to Concorde at supersonic speeds, it theoretically could have caused a catastrophic failure of the airframe. Although computer simulations predicted considerable problems, in practice Concorde could shut down both engines on the same side of the aircraft at Mach 2 without the predicted difficulties. During an engine failure the required air intake is virtually zero so, on Concorde, engine failure was countered by the opening of the auxiliary spill door and the full extension of the ramps, which deflected the air downwards past the engine, gaining lift and minimising drag. Concorde pilots were routinely trained to handle double engine failure.

Heating issues

Air compression on the outer surfaces caused the cabin to heat up during flight. Every surface, such as windows and panels, was warm to the touch by end of the flight. Besides engines, the hottest part of the structure of any supersonic aircraft, due to aerodynamic heating, is the nose. The engineers used Hiduminium R.R. 58, an aluminium alloy, throughout the aircraft due to its familiarity, cost and ease of construction. The highest temperature that aluminium could sustain over the life of the aircraft was 127 °C (261 °F), which limited the top speed to Mach 2.02. Concorde went through two cycles of heating and cooling during a flight, first cooling down as it gained altitude, then heating up after going supersonic. The reverse happened when descending and slowing down. This had to be factored into the metallurgical and fatigue modelling. A test rig was built that repeatedly heated up a full-size section of the wing, and then cooled it, and periodically samples of metal were taken for testing. The Concorde airframe was designed for a life of 45,000 flying hours.

Owing to air friction as the plane travelled at supersonic speed, the fuselage would heat up and expand by as much as 300 mm (almost 1 ft). The most obvious manifestation of this was a gap that opened up on the flight deck between the flight engineer’s console and the bulkhead. On some aircraft that conducted a retiring supersonic flight, the flight engineers placed their caps in this expanded gap, wedging the cap when it shrank again. To keep the cabin cool, Concorde used the fuel as a heat sink for the heat from the air conditioning. The same method also cooled the hydraulics. During supersonic flight the surfaces forward from the cockpit became heated, and a visor was used to deflect much of this heat from directly reaching the cockpit.

Concorde had livery restrictions; the majority of the surface had to be covered with a highly reflective white paint to avoid overheating the aluminium structure due to heating effects from supersonic flight at Mach 2. The white finish reduced the skin temperature by 6 to 11 degrees Celsius. In 1996, Air France briefly painted F-BTSD in a predominantly blue livery, with the exception of the wings, in a promotional deal with Pepsi. In this paint scheme, Air France were advised to remain at Mach 2 for no more than 20 minutes at a time, but there was no restriction at speeds under Mach 1.7. F-BTSD was used because it was not scheduled for any long flights that required extended Mach 2 operations.

Structural issues

Fuel pitch trim

Due to the high speeds at which Concorde travelled, large forces were applied to the aircraft’s structure during banks and turns. This caused twisting and the distortion of the aircraft’s structure. In addition there were concerns over maintaining precise control at supersonic speeds; both of these issues were resolved by active ratio changes between the inboard and outboard elevons, varying at differing speeds including supersonic. Only the innermost elevons, which are attached to the stiffest area of the wings, were active at high speed. Additionally, the narrow fuselage meant that the aircraft flexed. This was visible from the rear passengers’ viewpoints.

When any aircraft passes the critical mach of that particular airframe, the centre of pressure shifts rearwards. This causes a pitch down force on the aircraft if the centre of mass remains where it was. The engineers designed the wings in a specific manner to reduce this shift, but there was still a shift of about 2 metres. This could have been countered by the use of trim controls, but at such high speeds this would have caused a dramatic increase in the drag on the aircraft. Instead, the distribution of fuel along the aircraft was shifted during acceleration and deceleration to move the centre of mass, effectively acting as an auxiliary trim control.

Range

In order to fly non-stop across the Atlantic Ocean, Concorde was developed to have the greatest supersonic range of any aircraft. This was achieved by a combination of engines which were highly efficient at supersonic speeds, a slender fuselage with high fineness ratio, and a complex wing shape for a high lift to drag ratio. This also required carrying only a modest payload and a high fuel capacity, and the aircraft was trimmed with precision to avoid unnecessary drag.

Nevertheless, soon after Concorde began flying, a Concorde "B" model was designed with slightly larger fuel capacity and slightly larger wings with leading edge slats to improve aerodynamic performance at all speeds, with the objective of expanding the range to reach markets in new regions. It featured more powerful engines with sound deadening and without the fuel-hungry and noisy reheat. It was speculated that it was reasonably possible to create an engine with up to 25% gain in efficiency over the Rolls-Royce/Snecma Olympus 593. This would have given 500 mi (805 km) additional range and a greater payload, making new commercial routes possible. This was cancelled due in part to poor sales of Concorde, but also to the rising cost of aviation fuel in the 1970s.

Droop Nose

Concorde’s drooping nose, developed by Marshall Aerospace, enabled the aircraft to switch between being streamlined to reduce drag and achieve optimum aerodynamic efficiency, and not obstructing the pilot’s view during taxi, takeoff, and landing operations. Due to the high angle of attack the long pointed nose obstructed the view and necessitated the capability to droop. The droop nose was accompanied by a moving visor that retracted into the nose prior to being lowered. When the nose was raised to horizontal, the visor would rise in front of the cockpit windscreen for aerodynamic streamlining.

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. Prior to landing, the visor was again retracted and the nose lowered to 12.5° below horizontal for maximum visibility. Upon landing the nose was raised to the five-degree position to avoid the possibility of damage.

The Federal Aviation Administration had objected to the restrictive visibility of the visor used on the first two prototype Concordes and thus requiring alteration before the FAA would permit Concorde to serve US airports; this led to the redesigned visor used on the production and the four pre-production aircraft. The nose window and visor glass needed to endure temperatures in excess of 100 °C (212 °F) at supersonic flight were developed by Triplex.

Retirement

Concorde’s final flight; G-BOAF from Heathrow to Bristol, on 26 November 2003. The extremely high fineness ratio of the fuselage is evident.
On 10 April 2003, Air France and British Airways simultaneously announced that they would retire Concorde later that year. They cited low passenger numbers following the 25 July 2000 crash, the slump in air travel following the September 11, 2001 attacks, and rising maintenance costs. Although Concorde was technologically advanced when introduced in the 1970s, 30 years later, its analogue cockpit was dated. There had been little commercial pressure to upgrade Concorde due to a lack of competing aircraft, unlike other airliners of the same era such as the Boeing 747. By its retirement, it was the last aircraft in British Airways’ fleet that had a flight engineer; other aircraft, such as the modernised 747-400, had eliminated the role.

On 11 April 2003, Virgin Atlantic founder Sir Richard Branson announced that the company was interested in purchasing British Airways’ Concorde fleet for their nominal original price of £1 (US$1.57 in April 2003) each. British Airways dismissed the idea, prompting Virgin to increase their offer to £1 million each. Branson claimed that when BA was privatised, a clause in the agreement required them to allow another British airline to operate Concorde if BA ceased to do so, but the Government denied the existence of such a clause. In October 2003, Branson wrote in The Economist that his final offer was "over £5 million" and that he had intended to operate the fleet "for many years to come". The chances for keeping Concorde in service were stifled by Airbus’s lack of support for continued maintenance.

It has been suggested that Concorde was not withdrawn for the reasons usually given but that it became apparent during the grounding of Concorde that the airlines could make more profit carrying first class passengers subsonically. A lack of commitment to Concorde from Director of Engineering Alan MacDonald was cited as having undermined BA’s resolve to continue operating Concorde.

Air France

Air France made its final commercial Concorde landing in the United States in New York City from Paris on 30 May 2003. Air France’s final Concorde flight took place on 27 June 2003 when F-BVFC retired to Toulouse.

An auction of Concorde parts and memorabilia for Air France was held at Christie’s in Paris on 15 November 2003; 1,300 people attended, and several lots exceeded their predicted values. French Concorde F-BVFC was retired to Toulouse and kept functional for a short time after the end of service, in case taxi runs were required in support of the French judicial enquiry into the 2000 crash. The aircraft is now fully retired and no longer functional.

French Concorde F-BTSD has been retired to the "Musée de l’Air et de l’Espace" at Le Bourget (near Paris) and, unlike the other museum Concordes, a few of the systems are being kept functional. For instance, the famous "droop nose" can still be lowered and raised. This led to rumours that they could be prepared for future flights for special occasions.

French Concorde F-BVFB currently rests at the Auto & Technik Museum Sinsheim at Sinsheim, Germany, after its last flight from Paris to Baden-Baden, followed by a spectacular transport to Sinsheim via barge and road. The museum also has a Tu-144 on display – this is the only place where both supersonic airliners can be seen together.

British Airways[edit]

BA Concorde G-BOAB in storage at London Heathrow Airport. This aircraft flew for 22,296 hours between its first flight in 1976 and its final flight in 2000.

BA Concorde G-BOAC in its hangar at Manchester Airport Aviation Viewing Park]]
British Airways conducted a North American farewell tour in October 2003. G-BOAG visited Toronto Pearson International Airport on 1 October, after which it flew to New York’s John F. Kennedy International Airport. G-BOAD visited Boston’s Logan International Airport on 8 October, and G-BOAG visited Washington Dulles International Airport on 14 October. It has been claimed that G-BOAD’s flight from London Heathrow to Boston set a transatlantic flight record of 3 hours, 5 minutes, 34 seconds. However the fastest transatlantic flight was from New York JFK airport to Heathrow on 7 February 1996, taking 2 hours, 52 minutes, 59 seconds; 90 seconds less than a record set in April 1990.

In a week of farewell flights around the United Kingdom, Concorde visited Birmingham on 20 October, Belfast on 21 October, Manchester on 22 October, Cardiff on 23 October, and Edinburgh on 24 October. Each day the aircraft made a return flight out and back into Heathrow to the cities, often overflying them at low altitude. On 22 October, both Concorde flight BA9021C, a special from Manchester, and BA002 from New York landed simultaneously on both of Heathrow’s runways. On 23 October 2003, the Queen consented to the illumination of Windsor Castle, an honour reserved for state events and visiting dignitaries, as Concorde’s last west-bound commercial flight departed London.

British Airways retired its Concorde fleet on 24 October 2003. G-BOAG left New York to a fanfare similar to that given for Air France’s F-BTSD, while two more made round trips, G-BOAF over the Bay of Biscay, carrying VIP guests including former Concorde pilots, and G-BOAE to Edinburgh. The three aircraft then circled over London, having received special permission to fly at low altitude, before landing in sequence at Heathrow. The captain of the New York to London flight was Mike Bannister. The final flight of a Concorde in the US occurred on 5 November 2003 when G-BOAG flew from New York’s Kennedy Airport to Seattle’s Boeing Field to join the Museum of Flight’s permanent collection. The plane was piloted by Mike Bannister and Les Broadie who claimed a flight time of three hours, 55 minutes and 12 seconds, a record between the two cities. The museum had been pursuing a Concorde for their collection since 1984. The final flight of a Concorde world-wide took place on 26 November 2003 with a landing at Filton, Bristol, UK.

All of BA’s Concorde fleet have been grounded, drained of hydraulic fluid and their airworthiness certificates withdrawn. Jock Lowe, ex-chief Concorde pilot and manager of the fleet estimated in 2004 that it would cost £10–15 million to make G-BOAF airworthy again. BA maintain ownership and have stated that they will not fly again due to a lack of support from Airbus. On 1 December 2003, Bonhams held an auction of British Airways’ Concorde artifacts, including a nose cone, at Kensington Olympia in London. Proceeds of around £750,000 were raised, with the majority going to charity. G-BOAD is currently on display at the Intrepid Sea, Air & Space Museum in New York. In 2007, BA announced that the advertising spot at Heathrow where a 40% scale model of Concorde was located would not be retained; the model is now on display at the Brooklands Museum.

Chrysler Concorde (1998)

The Concorde was completely redesigned for the 1998 model year. The new design was similar to the new Chrysler LHS, however the two models each had a unique front end shape and different rear fascias. The "Second Generation" design was introduced in 1996 as the Chrysler LHX Concept Car. This concept vehicle had large 20" wheels, and a centrally located instrument cluster. The wheelbase was expanded to 124 inches (3,100 mm) to allow for rear passenger supplement restraints, rear occupant entertainment center and storage compartment.

Despite overall length increasing by 7.5 inches (190 mm), the second generation’s weight dropped by nearly a hundred pounds. This was achieved by extensive use of aluminum for the rear suspension, hood, as well as the two new engines. In addition the 214 hp (160 kW) 3.5-liter V6 engine, there was also a new 200 hp (149 kW) 2.7-liter V6 and 225 hp (168 kW) 3.2-liter V6. The 3.5-liter was redone and output upgraded to 253 hp (189 kW) and was available on the 2002-2004 Concorde Limited (formerly LHS).

Much was done in the design process to make the second generation LH sedans look more distinct from each other. The 1998 Concorde differed far greater from the Dodge Intrepid and the new 1999 Chrysler 300M (successor to the Eagle Vision), than did the first generation models. With the exception of the doors and roof, the Concorde shared little sheetmetal with the Intrepid and 300M. The new Concorde’s front end was underscored by a striking full-width grille, relocated to the front bumper to give the impression of a bottom breather. Sweeping curves and a more rounded front end also helped set the Concorde apart from the Intrepid and 300M. The second generation Chrysler LHS had an appearance very similar to the Concorde; The only major differences being its more centrally located single frame grille and amber turn signals on the taillights.

As in the previous generation, six passenger seating with a front bench seat and column shifter was optional. Cloth seating was standard on base LX with leather seating optional. Leather was standard on upscale LXi and later Limited models.

The Concorde, 300M, and Intrepid were discontinued in 2004. The all-new Chrysler 300 replaced the Concorde (and 300M) in late 2004 as a 2005 model.

The Concorde 2nd generation replaced the first generation car (launched in 1991), itself derived from the AMC division Eagle Premier (and Dodge Monaco). Interestingly, these two AMC products were directly related to the then-new Renault 25 and inherited the Renault north-south installation of the powertrains, with the engine mounted ahead of, and driving, the front axle. This layout is very similar to that used in the larger Audis, thus permitting the installation of a all-wheel-drive system for added traction, though there were no volume models of either the AMC division cars, or the latter LHS platform Chryslers that used this system.

Notes on each of the aircraft Concorde and automotive Concorde are taken from excerpts published on Wikipedia.

The two models shown here, the Aérospatiale-BAC Concorde and the second generation Chrysler Corcorde have been designed in Lego. The aircraft in approximately 1:50 scale, and the car in miniland (1:21) scale for Flickr LUGNuts 79th Build Challenge, – "LUGNuts goes Wingnuts" – featuring automotive models named after, inspired by, or related to aircraft.

Posted by lego911 on 2014-06-13 23:46:51

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