How do birds fly, I want to know how to explain the process of a bird flight?

Question

Can someone explain the process of a bird flight??

Answer 1

The shape of a bird's wing generates lift just like an airplane's wing.

The flapping wing generates thrust pointed down and behind the bird, thrusting it up and forward.  

The combination of the two results in flight.

Answer 2

The bird's wings acts like an airfoil, which is how a plane's wings work.

Basically the rise in the wing's surface causes a slower air flow over the top, and so there is a lower air pressure on top than on the bottom; this creates lift.  The flapping action only accelerates this because the bird can vary shape of its wing to improve its lift in each stroke.  Birds also use thermal currents (warm air currents flowing upward) to gain altitude.  This is how a hawk is able to stay aloft for hours without using much energy.

The rest of the structure of the bird is designed for flight, its bones are hollow, its wings are attached to strong muscles and are long enough and properly shaped to generate flight.  The bones in it hold the airfoil rigid and change its shape during flight and their feathers can be used to expand the wing shape and alter the air flow over it to optimize flight conditions and control.

The tail of the bird, much like the tail of an aircraft provide a little additional lift, but are mostly there to act as a rudder and provide control.

To take off a bird needs to reach a specific speed, it does so by running, facing into a wind or by jumping off a tree or cliff and using its dive speed to obtain flight.  If you have ever seen an albatross try to take off they look clumsy as they try to achieve take-off speed, but are quite graceful it the air and their long wings allows them to stay aloft for a long time.

Penguins fly, but through the water, their wings act as airfoils in the water, although they are not large enough for the bird to actually take off into the atmosphere.

According to Wikipedia:  http://en.wikipedia.org/wiki/Bird_flight

"The fundamentals of bird flight are similar to those of aircraft. Lift force is produced by the action of air flow on the wing, which is an airfoil. The lift force occurs because the air has a lower pressure just above the wing and higher pressure below.

When gliding, both birds and gliders obtain both a vertical and a forward force from their wings. This is possible because the lift force is generated at right angles to the air flow, which in level flight comes from slightly below the wing. The lift force therefore has a forward component.

When a bird flaps, as opposed to gliding, its wings continue to develop lift as before, but they also create an additional forward and upward force, thrust, to counteract its weight and drag. Flapping involves two stages: the down-stroke, which provides the majority of the thrust, and the up-stroke, which can also (depending on the bird's wings) provide some upward force. At each up-stroke the wing is slightly folded inwards to reduce upward resistance. Birds change the angle of attack between the up-stroke and the down-stroke of their wings. During the down-stroke the angle of attack is increased, and is decreased during the up-stroke.

There are three major forces that impede a bird's aerial flight: frictional drag (caused by the friction of air and body surfaces), form drag (due to frontal area of the bird, also known as pressure drag), and lift-induced drag (caused by the wingtip vortices)....

The bird's forelimbs, the wings, are the key to bird flight. Each wing has a central vane to hit the wind, composed of three limb bones, the humerus, ulna and radius. The hand, or manus, which ancestrally was composed of five digits, is reduced to three digits (digit II, III and IV), the purpose of which is to serve as an anchor for the primaries, one of two groups of flight feathers responsible for the wing's airfoil shape. The other set of flight feathers, which are behind the carpal joint on the ulna, are called the secondaries. The remaining feathers on the wing are known as coverts, of which there are three sets. The wing sometimes has vestigial claws. In most species these are lost by the time the bird is adult (such as the highly visible ones used for active climbing by Hoatzin chicks), but claws are retained into adulthood by the Secretary Bird, screamers, finfoots, ostriches, several swifts and numerous others, as a local trait, in a few specimens. The claws of the Jurassic theropod-like Archaeopteryx are quite similar to those of the Hoatzin nestlings."

See the rest of the article for more information.

The mechanics of flight are determined through fluid dynamics where the air is considered to be a slow moving fluid.

According to Wikipedia:  http://en.wikipedia.org/wiki/Chickens

"Domestic chickens are not capable of long distance flight, although lighter birds are generally capable of flying for short distances, such as over fences or into trees (where they would naturally roost). Chickens will sometimes fly to explore their surroundings, but usually do so only to flee perceived danger. Because of the risk of escape, chickens raised in open-air pens often have one of their wings clipped by the breeder—the tips of the longest feathers on one of the wings are cut, resulting in unbalanced flight which the bird cannot sustain for more than a few meters, and it is thus discouraged from flying at all."

Mankind has breed the chicken to be a larger bird and so less capable of flight.  Pigeons were once used to carry messages and they are still used in races.

Answer 3

since last many years there are changes take place in all form of living beings. the human has been evolved from the apes with modified things like hand and modified brain. similarly bird have modified limbs as their wings. they have air cavity in their bones which help them to reduce their weight and fly higher.their feather are also  light weight  and a good protector from weather .