Flight

For other uses, see Flight (disambiguation).

Hummingbird

Flight is the process by which an object achieves sustained movement either through the air (or movement beyond earth\'s atmosphere, in the case of spaceflight) by aerodynamically generating lift, propulsive thrust or aerostatically using buoyancy.

Forces for flight

Main forces on a heavier-than-air aircraft

Main article: Aerodynamics

Forces relevant to flight are

• Propulsive thrust: (except in gliders)
• Lift: created by the deflection of the airflow (usually by wings)
• Drag: created by airflow
• Weight: (created by gravity)
• Buoyancy: for lighter than air flight

These forces must be balanced for stable flight to occur.

The stabilization of flight angles (roll, yaw and pitch) and the rates of change of these can involve horizontal stabilizers (i.e. \'a tail\'), ailerons and other movable aerodynamic devices which control angular stability i.e. flight attitude (which in turn affects altitude, heading).

Animal flight

Female Mallard Duck

Tau Emerald dragonfly

Main article: Flying and gliding animals

The most successful groups of living things that fly are insects, birds, and bats. Each of these groups\' wings evolved separately from different structures. See also Bird flight. Also successful were the extinct Pterosaurs, an order of reptiles contemporaneous with the dinosaurs.

Bats are the only mammals capable of true flight. However, there are several gliding mammals which are able to glide from tree to tree using fleshy membranes between their limbs; some can travel hundreds of meters in this way with very little loss in height. Flying tree frogs use greatly enlarged webbed feet for a similar purpose, and there are flying lizards which employ their unusually wide, flattened rib-cages to the same end. Certain snakes also use a flattened rib-cage to fly, with a back and forth motion much the same as they use on the ground.

Flying fish can glide using enlarged wing-like fins, and have been observed soaring for hundreds of meters using the updraft on the leading edges of waves. It is thought that this ability was chosen by natural selection because it was an effective means of escape from underwater predators.

Most birds fly (see bird flight), with some exceptions. The largest birds, the ostrich and the emu, are earthbound, as were the now-extinct dodos, while the non-flying penguins have adapted their wings for use under water. Most small flightless birds are native to small islands, and lead a lifestyle where flight would confer little advantage. The Peregrine Falcon is the fastest animal in the world; its terminal velocity exceeds 370 km/h (199 mph) in a dive.

Among living animals that fly, the wandering albatross has the greatest wingspan, up to 3.5 meters (11.5 ft); the great bustard has the greatest weight, topping at 21 kilograms (46 pounds).http://www.trumpeterswansociety.org/id.htm

Among the many species of insects, some fly and others do not (See insect flight).

Mechanical flight

Main article: Aviation

Mechanical flight: A Robinson R22 Beta helicopter

Mechanical flight is the use of a machine to fly. These machines include airplanes, gliders, helicopters, autogyros, airships, balloons, ornithopters, and spacecraft. Gliders provide unpowered flight. Another form of mechanical flight is parasailing where a parachute-like object is pulled by a boat. In an airplane lift is created by the wings; the shape of the wings of the airplane are designed specially for the type of flight desired. There are different types of wings: tempered, semi-tempered, sweptback, rectangular, and eliptical. The shape of the design of the wing is called an airfoil, which is a device that creates lift by differences in pressure.

Religion, mythology and fiction

In religion, mythology and fiction, human or anthropomorphic characters sometimes have the ability to fly independently. Well-known examples include angels in the Hebrew Bible, Daedalus in Greek mythology, and Superman in comics. Other non-human legendary creatures, such as some dragons and Pegasus, are also depicted with an ability to fly.

The ability to fly may come from wings or other visible means of propulsion, from superhuman or god-like powers, or may simply be left unexplained.

See also

Wikimedia Commons has media related to:

Flight

Look up Flight in
Wiktionary, the free dictionary.

• Aerodynamics
• Aviation
• Flying and gliding animals
• Levitation
• Transvection (flying)

References

External links

• See how it flies: a new spin on the perceptions, procedures, and principles of flight
• \'Birds in Flight and Aeroplanes\' by Evoluntionary Biologist and trained Engineer John Maynard-Smith Freeview video provided by the Vega Science Trust.

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