How does a plane takes off?

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DAVID C

Its wind speed over the wing, and is goverened by Bernoulli's principle - states that in an ideal fluid (low speed air is a good approximation), with no work being performed on the fluid, an increase in velocity occurs simultaneously with decrease in pressure or gravitational energy. This principle is a simplification of Bernoulli's equation, which states that the sum of all forms of energy in a fluid flowing along an enclosed path (a streamline) is the same at any two points in that path. It is named after the Dutch/Swiss mathematician/scientist Daniel Bernoulli

So in English, a simple explanation would be that the wing is larger on the upper surfce, than it is on the lower one. thus when the air flow hits it, it is divided. This causes a pressure differential above and below a wing. the one under the wing is greater, and pushes the wing up.

However, this explanation often uses 'false' information, such as the incorrect assumption that the two parcels of air which separate at the leading edge of a wing must meet again at the trailing edge, and the assumption that it is the difference in air speed that causes the changes in pressure.

In air (or comparably in any fluid), lift is created as flow interacts with an airfoil or other body and is deflected downward. The plane on the runway, has a wing that is angled downward. The propeller, or jet moves the plane forward, thus the force created by this deflection of the air creates an equal and opposite upward force according to Newton's third law of motion. The deflection of airflow downward during the creation of lift is known as downwash.

It is important to note that the acceleration of the air does not just involve the air molecules "bouncing off" the lower surface of the wing. Rather, air molecules closely follow both the top and bottom surfaces, and so the airflow is deflected downward. The acceleration of the air during the creation of lift has also been described as a "turning" of the airflow.

this is enough to lift the weight of the plane, and allow it to accelerate to 50-70 mph. the wing thus takes on its flying profile, but on large passenger jets, additional truning is created by Flaps, which extend out of the wing, and cause huge downwash.

The Helmholtz theorem states that circulation is conserved; put simply this is conservation of the air's angular momentum. When an aircraft is at rest, there is no circulation. As the flow speed increases (that is, the aircraft accelerates in the air-body-fixed frame), a vortex, called the starting vortex, forms at the trailing edge of the airfoil, due to viscous effects in the boundary layer. Eventually the vortex detaches from the airfoil and gets swept away from it rearward. The circulation in the starting vortex is equal in magnitude and opposite in direction to the circulation around the airfoil. Theoretically, the starting vortex remains connected to the vortex bound in the airfoil, through the wing-tip vortices, forming a closed circuit. In reality, the starting vortex is dissipated by a number of effects, as are the wing-tip vortices far behind the aircraft. However, the net circulation in "the world" is still zero as the circulation from the vortices is transferred to the surroundings as they dissipate.

The aircraft starts to fly at the point that this vortex breaks from the wing. The large jet then lifts the flaps back into the wing, thus reducing the lift of the wing, but also reducing the drag, so the plane can speed up, to compensate the loss of wing area.

The circulation of a big wing is so much during take-off, that light aircraft can not take off after a large jet has done so.

echo

It goes forward really fast then it goes up.

The Angry Scotsman

Bernoulli's principle.

BARROWMAN

The forces which act on an aircaraft are lift, weight, drag and thrust. Weight and drag are the forces which inhibit the aircraft's flight whil lift and thrust are the forces which eneble the flight. Lift is provided by the aircraft's wing surfaces and thrust by the power sources. In simple terms the drag is overcome by the thrust and lift overcomes the weight and the aircraft flies.

on the wagon

if it`s Aer Lingus
a huge elastic band wound up

kicking_back

a engines move the plane forward so that it forces air above and below the wings. the wings are shaped so that the top of the wing has more surface area for the wind to travel over to get to the aft edge from the leading edge of the wing. this means the wind has to move faster over the top of the wing which causes lower air pressure at the top of the wing and the high pressure air under the wing pushes the plane up into the sky.

nivedita p

A plane takes off with the help of thrust and drag. It gains adequate speed by powering up all engines gradually to the correct speed and then the flaps on the wings lower themselves and due to the air passing under the wings, the plane goes upward at the angle till it reaches the flight level assigned to it by the ATC.

goalaska

Lift! When it reaches a certain speed, the air rushing under the wings Makes it Lift-Off

CAPTAIN BEAR

By flapping its wings and running down the runway to
give it momentum.

It Co$t To Be Around The Bo$$

Very carefully very carefully my friend....

thecoldvoiceofreason

An aeroplanes wing is shaped to make air flow downwards producing lift, produce enough lift - ie. with more speed and the force of that lift becomes enough to defeat the gravitational forces that are keeping the plane on the ground, hence you take off.

NUFC_4_LIFE

flaps its wings!

spud

Ask a bee.

JAMES

the pilot pulls the throtlle back until the palnce reaches a high speed then he raises the nose of the plane and the ascent starts

Billy Nee Mates

Why don't you make yourself a set of wings and jump off a big buildind and then you will be able to understand how a plane takes off

KMOX

Most of these answers are correct, however, any real pilot will tell you there is only one thing that makes airplanes fly: money.

:)

...that and a principle that some guy named Bernoulli came up with.

farshadowman

wing angle, thrust and lift

Geeza Sooka Yerlips

It travels faster on the ground than the speed at which the earth is spinning, so the force of gravity stops working.

hey

very fast very loud

nicolefrenzy

like a bird

GlitterRain

It has wheels which are it's legs. The plane travels on the wheels so it can take off. Like a run up the faster you go the more force you can have to go far.

Nanny Bev

along the runway

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