What creates lift during take-off?

Question

if it is the wings and not the engine, how does it do so?? what makes the plane actually lift off the ground at the end of the runway? what is the mechanism here?

Answer 1

it's how fast the plane is going and the shape of the wings, if you sit near the wings on a plane you can see at the back and front of the wings there are little flaps that move as you're flying, they change the way the air flows over the wings and therefore whether the plane is pushed up or down

Answer 2

Bernoulli effect

Answer 3

Hmmmm.....well, the engines generate a horizontal force which moves the plane through the air. Due to the shape of the wings, the air passing over the top of the wings has further to travel than the air passing underneath the wings, so the air passing over the wings is travelling faster than the air passing under the wings. Faster air means less air pressure, so there is more air pressure under the wings than on top of the wings, the net effect being a "lift" force on the wings. The faster the plane is travelling horizontally, the greater the lift on the wings.

Answer 4

The engine provides the forward motion, the shape of the air-foil creates a lower pressure on the top of the wing, this creates the lift needed to get the craft off the ground.

Answer 5

Lift is produced because the wind traveling at the top of the wings is faster than that traveling under it, on top of the wing there is lower pressure since pressure is low when a fluid is flowing fast.The difference in pressure on top and under the wings produces lift.To make air travel above and under the wing   thrust is needed which is produced by the engines.

Answer 6

what creates lift during take-off?

The same thing that generates lift during flight.

Next time you are driving somewhere in your car, stick your hand out the window.  As you angle your hand you will feel it pushed up or down by the wind.  That is lift.  That is how planes fly.  Simple.

Edit:  A lot of the other answers here go into more detail about how the lift is caused by the speed of air above and below the wing. This is correct, although it is exactly equally correct to say the lift is caused by the rate of change of momentum of the air flow.

However, many of the answers are claiming this pressure difference is due to the air moving faster on top due to having to meet up with the same air below.  This is simply incorrect.  There is no reason air traveling farther over the top of the wing would ever have to 'catch up' with the air travelling the shorter distance beneath the wing.

An example, a flat board clearly generates lift if it is angled with respect to the wind.  There is no greater distance for the air to travel over the top of the board than under the board.

Answer 7

Bernoulli's Principle is the basis of lift over an asymmetric airfoil (most airplane wings).

Lift = Coefficient of lift X ((density x velocity squared) / 2) X wing area.

As air meets the front of the airfoil it splits between the "top" and "bottom".  The curved surface requires the air molecule to travel further than the flat surface of the Airfoil.  Bernoulli's Principle discusses a pressure differential due to the higher and lower speeds of the air this forms a low pressure on the curved (typically the top side of the wing) resulting in a higher pressure on the bottom.  Air typically moves from High to Low pressure this forces the wing upward.   This is a brief explanation be sure to research this for more understanding of how the lift equation and Bernoulli's principle work together to make an airplane fly.

Remember Aerodynamics is Theory.

Additionally, Lti you are a clown.  If you angle a piece of cardboard and it "produces lift" then why?  Do you think it is a shorter on the bottom side or the top side of the piece of cardboard from front to back?  Unless that piece of cardboard has "0" thickness (impossible) then when it is anything other than parallel to the relative wind one the air traveling over it has farther to go over the top than the bottom.  In addition with disturbed air on the top it produces more drag, and if you think it works then get a lot of refrigerator boxes, cut them up, stick them out the window of your car and see if you can fly.  The question is why does an airplane lift off the ground not how your hand or cardboard reacts out the car window.

Answer 8

the speed of air passing over the wings, due to the shape you get less pressure on top of the wing than bottom so it 'lifts'

Answer 9

It is a combination of things  The air on top of the wings goes slower creating a vacuum  and the air craft lifts. also the wing surfaces , ie the ailerons. The engines also push more air over the wings giving even more lift. That is a basic answer

Answer 10

There are 4 forces constantly working in opposition during

flight. The first is "drag" (the tendency for air -a fluid- to resist movement through it). "Drag" must be overcome in order for a plane to fly. This is done by the opposing force called

"thrust", produced by prop or turbine engines. The other factor working against flight is (of course) gravity.

Gravity is overcome by the opposite force, "lift".

When air is moving, it has less pressure, the faster it moves.

Try this simple experiment which illustrates this fact:

Take a sheet of paper, and hold the edge to your face,

directly below your lips. Pucker your lips and blow.

You'll see the paper move upwards, towards the area of low

pressure created by your moving breath.  A wing works the

same way. If you were to look at an airplane wing from the

tip, inward, you'd see the top surface is curved upward, while

the lower surface is almost flat.  Because of this shape,

the air moving over the wing has to go faster to meet the

same air which has gone below the wing. This produces

an area of lower pressure on top of the wing. The wing

(like the sheet of paper) wants to move into the low pressure.

This is "Lift"  As the plane (wing) moves faster, the pressure

difference (lift) increases. Eventually the force of lift is greater

than the weight of the plane (gravity), and the plane leaves

the ground. When an airplane is taking-off or landing, and

the plane is going slower, additional lift is created by extending "flaps" from the trailing-edge of the wing. This gives the wing more

surface-area for more lift at low speeds, but it also creates

more "drag". So on all modern airliners, the flaps can be

extended (for low speeds) or retracted (for normal flight).

If a plane in flight loses speed to the point that there's not

enough lift to counter-act gravity, the plane drops.

This is called a "Stall".  A pilot must do one of two things

to recover from a stall; pitch the nose down to increase

speed, or add power to the engine(s) to increase thrust.

In all modern airplanes, the control yoke (steering stick),

actually vibrates in the pilots hands to warn of an approaching

stall, before it happens. This stall- warning device is called

a "Stickshaker".