Airbus A380

Airbus A380Presented by: Joel Alex RoyConnectionsEagleAncient Mongolian bow19th-century rocketBicycle pump

Airbus A380World's largest passenger airlinerProvides seating for up to 853 people in all-economy class configurationsMax. range of 15,400 kilometres, sufficient to fly from New York to Hong Kong non-stopCruising speed of Mach 0.85Aerodynamic EfficiencyMax. Take-Off Weight over 650 tonnes.Wings must be short enough to fit within the International regulations on the maximum size of aircrafts. Yet, they must generate enough lift force.From Bernoulli's principle, the pressure on the upper surface where the flow is moving faster is lower than the pressure on the lower surface. The pressure difference thus creates a net aerodynamic force, pointing upward and downstream to the flow direction.

Fluids are forced to flow from high to low pressure, and the air below the wing tends to migrate toward the top of the wing via the wingtips. The air does not escape around the leading edge of the wing due to airspeed, but it can flow around the tip.As a consequence, air flows from below the wing and out around the tip to the top of the wing in a circular fashion. This leakage will raise the pressure on top of the wing and reduce the lift that the wing can generate.

Eagles glide high above the ground by utilizing updrafts, such as thermals - warm air that rises and can carry the bird along with it.Eagle wings cannot be too long. Otherwise the turning circle would take it outside the thermal zones.So the wings are adapted for max. lift with min. length.Eagles curl their tip feathers upwards to get max. lift, until they are almost vertical.This natural adaptation reduces the strength of the vortices produced by blocking the path of air that circulates from underneath the wing.

Winglets block the path of the vortex trying to curl around the wingtip. The entire surface of the wing hence generates lift, effectively doing the same job as a longer wing.Winglets can be made almost vertical to keep the total wingspan to an absolute minimum.It reduces induced drag, increasing fuel efficiency and performance.Without the winglets, the A380s wings would have to be 3m longer to achieve the same lift.

Saving WeightTo keep the running costs of the A380 to a minimum, the weight of the aircraft should be kept to a bare minimum.The outer skin of the A380 should be kept as light as possible, without making it too fragile.A punctured fuselage can cause cabin depressurization, asphyxiating the passengers.Damage to the wings could send the aircraft out of controlIn 1200 AD, the Mongols invented the first composite bow.A bow has to handle two different forces at the same time. When a bow is drawn, the outside stretches, while the inside squeezesUsing a combination of sinew (tensile forces), bone (compressive), and animal glue, bows were pressed and wrapped with birch bark.Composite Mongolian bows provided Genghis Khan with military dominance.

11Carbon-fibre reinforced plastic, glass-fibre reinforced plastic and quartz-fibre reinforced plastic are used extensively in wings, fuselage sections, tail surfaces, and doors.The composite material GLARE (GLAss-REinforced fibre metal laminate) is used in the upper fuselage and on the stabilisers' leading edges. Unlike earlier composite materials, GLARE can be repaired using conventional aluminium repair techniques.

Its major advantages over conventional aluminium are:Better "damage tolerance" behaviour (especially impact and metal fatigue, as the elastic strain is larger than other metal material it can consume more impact energy. It is dented easier but has a higher penetration resistance )Better corrosion resistanceBetter fire resistanceLower specific weight

Evacuation & SafetyThe upper exits of the A380 stand nearly 8m from the ground, which is a long way for an evacuation.To satisfy International regulations, all 853 passengers must evacuate the plane using only half the no. of exits.The evacuation slides on the A380 are the biggest in the world. But regulations require the slides to inflate within 6 seconds.Pressurized gases inflate at a slow speed and will not be able to take the weight of passengers.

19th century rockets utilize gunpowder as their key ingredient and produce a large amount of gaseous byproduct.Rocket gases, acting as a booster in combination with compressed gases along with aspirators can be used to quickly inflate the slides.

An aspirator is a device that produces vacuum by means of the Venturi effect. As the funnel gets narrower, the gas flow speeds up, causing the pressure to drop. This creates a vacuum effect, which sucks in air from the surrounding to inflate the evacuation slide.With this device, the A380s slides can inflate within 4 seconds.

LandingLanding impacts are absorbed by the landing gear. For an aircraft like the A380, it should be strong enough to bear the immense weightEach set of wheels are cushioned by shock absorbers, bringing the passengers safely to the ground.The shock absorber is a piston that moves inside a cylinder just similar to a cycle pump. As the air inside the cylinder is compressed, the shock is absorbed.

In the A380's landing gear, instead of just air, oil is used.As greater energy is required to compress the highly viscous oil into a chamber, greater shock is absorbed and the landing is smoother.

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