How They Work : “The Concorde Aircraft (Cont’d)”

As we saw in our previous article, the Concorde flies faster and higher than most commercial jets, viz the Boeing 747 aircraft cruises at about 900 kph and the Airbus A380, in contrast with the Concorde that cruises at 2,170 kph, the Concorde travels faster than the speed of sound and almost twice as high as other commercial jets, it has several features that set it apart from other aircraft. Streamlined design, Needle-like fuselage, Swept-back delta wing, Moveable nose, Vertical tail design, Engine design, Engines built into the wing, Afterburners, Main and auxiliary fuel tanks, High-reflectivity paint. Its eagle like, Streamlined Design gives it advantages. As any aircraft approaches the speed of sound (1100 ft/s, 343 m/s), the air pressure builds up in front of the aircraft, forming a “wall” of air. To punch through that wall of air, planes must be streamlined. To streamline the Concorde, the following designs have been implanted: Needle-like fuselage, Swept-back delta wing, moveable nose and Vertical tail design. The fuselage (body) of the Concorde is only 2.7 metres wide as compared with a 747 that is 6.1 metres wide). The length of the Concorde is about 61.7 metres, just slightly shorter than a 747. The long, narrow shape of the Concorde reduces the dragon the plane as it moves through the air. The wing of the Concorde is thin, swept back and triangular, whereas a 747’s wing is swept back but rectangular. Also, there is no space between the fuselage and the wing of the Concorde as there is in the 747. The Concorde’s wing is called a delta-wing design and does the following; reduces drag by being thin and swept back (55 degrees with the fuselage). Provides sufficient lift for take-off and landing at subsonic speeds; it provides stability in flight so that no horizontal stabilizers are needed on the tail. The Concorde has a longer, needle-shaped nose compared to most commercial jets. The nose helps penetrate the air, and can be tilted down upon take-off and landing (13 degrees) so that the pilots can see the runway. (Delta-winged aircraft have a steeper angle of attack during take-off and landing than other types of aircraft.) Also, the Concorde’s nose has a visor to protect the windshield when flying at supersonic speeds. As mentioned above, because the delta wing provides stability to the aircraft, the Concorde does not require a horizontal stabilizer on the tail like most other aircraft. These designs in the body and wings of the aircraft allow it to move easily through the air at high speed. The engines on the Concorde provide the thrust necessary for take-off, cruising and landing. The Concorde has four Rolls Royce Olympus 593 turbo jet engines. Each engine generates 18.7 tons of thrust. Together, the four engines burn 25,629 litres of fuel per hour. The location and type of engines on the Concorde’s are different from on other jets. The Concorde’s engines are attached directly to the underside of the wing without engine struts. This design reduces air turbulence and makes for a more stable engine. At supersonic speeds, engine struts would be overstressed and likely to break. The Concorde’s engines use after burners to gain additional thrust to reach supersonic speeds. Afterburners mix additional fuel with the exhaust gases from the primary combustion chamber and burn it to get more thrust. Afterburners are typically used on supersonic military jets. There are several components that enable and support the speed and power achieved by the Concorde. The Concorde has 17 fuel tanks that can hold a total of 119,500 litres of kerosene fuel. The main tanks are located in each wing (five on each side) and fuselage (four). The Concorde also has three auxiliary or trim fuel tanks (two in front and one in the tail). Here is what the trim tanks are used for: As the Concorde reaches supersonic speeds, its aerodynamic centre of lift shifts backward. This shift drives the nose of the aircraft downward. To maintain balance, fuel is pumped backward into the trim tanks. The redistribution of fuel balances the aircraft by making its centre of gravity match the centre of lift. When the plane slows down, the centre of lift shifts forward. Fuel is then pumped forward into the trim tanks to compensate. So, unlike other jets, the Concorde uses fuel not only for the engines, but also for aerodynamic stability. High-reflectivity Paint; because the Concorde moves faster than sound, the air pressure and friction (collision with air molecules) really heat up the plane. The temperature of the aircraft’s skin varies from 261 degrees Fahrenheit (127 degrees Celsius) at the nose to 196 F (91 C) at the tail. The walls of the cabin are warm to the touch. To help reflect and radiate this heat, the Concorde has a high-reflectivity white paint that is about twice as reflective as the white paint on other jets. The heat encountered by the Concorde causes the airframe to expand about 17.8 cm in flight. To minimize the stress on the aircraft, the Concorde is made of a special aluminium alloy (AU2GN) that is lightweight and more heat-tolerant than titanium. eddie@afrowebs.com