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Aviation

Aviation is the activities surrounding mechanical flight and the aircraft industry. Aircraft includes fixed-wing and rotary-wing types, morphable wings, wing-less lifting bodies, as well as lighter-than-air craft such as hot air balloons and airships.

Aviation began in the 18th century with the development of the hot air balloon, an apparatus capable of atmospheric displacement through buoyancy. Some of the most significant advancements in aviation technology came with the controlled gliding flying of Otto Lilienthal in 1896; then a large step in significance came with the construction of the first powered airplane by the Wright brothers in the early 1900s. Since that time, aviation has been technologically revolutionized by the introduction of the jet which permitted a major form of transport throughout the world.

Early beginnings

There are early legends of human flight such as the stories of Icarus in Greek myth, Jamshid and Shah Kay Kāvus in Persian myth, and the flying automaton of Archytas of Tarentum (428–347 BC). Later, somewhat more credible claims of short-distance human flights appear, such as the winged flights of Abbas ibn Firnas (810–887), Eilmer of Malmesbury (11th century), and the hot-air Passarola of Bartholomeu Lourenço de Gusmão (1685–1724).

Lighter than air

The modern age of aviation began with the first untethered human lighter-than-air flight on November 21, 1783, of a hot air balloon designed by the Montgolfier brothers. The practicality of balloons was limited because they could only travel downwind. It was immediately recognized that a steerable, or dirigible, balloon was required. Jean-Pierre Blanchard flew the first human-powered dirigible in 1784 and crossed the English Channel in one in 1785.

Rigid airships became the first aircraft to transport passengers and cargo over great distances. The best known aircraft of this type were manufactured by the German Zeppelin company.

The most successful Zeppelin was the Graf Zeppelin. It flew over one million miles, including an around-the-world flight in August 1929. However, the dominance of the Zeppelins over the airplanes of that period, which had a range of only a few hundred miles, was diminishing as airplane design advanced. The “Golden Age” of the airships ended on May 6, 1937 when the Hindenburg caught fire, killing 36 people. The cause of the Hindenburg accident was initially blamed on the use of hydrogen instead of helium as the lift gas. An internal investigation by the manufacturer revealed that the coating used in the material covering the frame was highly flammable and allowed static electricity to build up in the airship.[5] Changes to the coating formulation reduced the risk of further Hindenburg type accidents. Although there have been periodic initiatives to revive their use, airships have seen only niche application since that time.

Heavier than air

In 1799, Sir George Cayley set forth the concept of the modern airplane as a fixed-wing flying machine with separate systems for lift, propulsion, and control. Early dirigible developments included machine-powered propulsion (Henri Giffard, 1852), rigid frames (David Schwarz, 1896) and improved speed and maneuverability (Alberto Santos-Dumont, 1901).