why doesnt a plane just fall out of the sky cause of its weight?

Answer 1

Bernoulli's principle of flight. Air travelling over the curved upper surface of the wing is forced to cover a greater distance, speeding the air up. This air becomes low pressure. The air travelling under the wing over a relatively flat surface travels slower and maintains a higher pressure. As the speed of the airplane increases, the pressure over the wing becomes far less then the pressure under the wing, and the airplane is lifted up.

Answer 2

The basic principle of flight is the lift under the aerofoil (the wing).
In order to keep an aeroplane in the air, the air pressure under the wing needs to be greater than that above it. As you probably know, if you compress air you increase its pressure, and so the greater the thrust you can produce with engines the faster you can go and the faster you can get air under the wing. It would be very hard to do this with just speed though, and so the wing is shaped in a way that passes air at low pressure over the top and at high under the bottom. If you or anybody you know has a car with a spoiler on it, go and look at the shape: a spoiler is just an upside down wing to push the car on to the road to help traction.
The air pressure under the wing is known in the aero industry as the "lift" and the power produced by the engines as the "thrust". The two combined keep it in the air, and if the craft flies too slowly it will begin to drop. Against them, you have "drag" which is a slowing of the aircraft due to air resistance and weight, which is of course the mass of the aircraft and gravity.
In modern design and particularly for very large aircraft it is usual for the aerofoil not only to be the wing but the lower half of the hull too; the more pressure you can get under the hull the less strain the wings are taking.
The airflow is tested in a wind tunnel; BAe used to have a huge one producing thousands of pounds of thrust that was more powerful than a tornado.

Answer 3

An airplane stays aloft because its "lift" exceeds its weight. Lift occurs because the shape of the wing causes air passing over the wing to be stretched relative to air passing under the wing. The "stretched" air exerts less pressure on the top of the wing than the air passing below the wing exerts on the wings underside. As a result, the air underneath pushes the wing up, creating lift. Generally, the faster a plane is traveling, the more lift is created, which is why aircraft don't lift off a runway until they reach a certain speed. (All this, by the way, is in accordance with Bernoulli's Principle.)

Answer 4

Oh but they do fall out of the sky cause of their weight. All of the time. In fact, most never get airborne, and what you see in the sky are really scale models put up there by the airlines so that the public will be fooled into buying tickets cause they think the whole thing is safe.

Shhh though. It's a secret, don't tell anyone.

Sash.

Answer 5

It is the principle of LIFT. But I understood that because of the shape of the wing (the top having more surface than the bottom) caused the air to travel faster BENEATH the wing causing the plane to lift from the ground. It just stands to reason that air will travel more quickly over a shorter distance than a longer one.

Answer 6

I would suggest a practical, easy experiment which will demonstrate lift. Take a sheet of thin flexible paper, hold it to your face at your lower lip, exhale forcefully and if the paper is flexible enough you will note that the paper rises up to meet the air stream from your mouth. You will also note there no air steam on the bottom of the paper pushing it up! It is the fact that your breath creates a low pressure area on the top of the paper which lifts it up. Other writers have mentioned the principal which all wings use to obtain lift and this is just an easy practical example.

Answer 7

Pressure on a surface is prortional to the root mean sqare speed of the fluid molecules and their density. The aerofoil shape creates a greater velocity of molecules above the aerofoil parallel to the aerofoil or wing. This creates a pressure difference, giving a net upward 'lift'=F=deltaPxA. Obviously the greater the engine thrust, the greater the wing area, the greater the lift,counteracted somewhat by the reduction in the density of air as you fly higher.

Answer 8

It is because of lift generated by the wings from the faster air flowing over the top of the wings versus the bottom. This is called Bernoulli's Principle. Check out howstuffworks.com they have about 20 pages of info on how an airplane flies.

Answer 9

Because the airflow over the wings generates enough lift to keep it airborne.

Ever stick your hand out the window going down the highway when you were a kid and let the wind pull your arm up and down? Same principle.

Answer 10

Switch the engines off and if you're very lucky it will just glide to the ground. Without lift from the wings gravity will take over.