how does an aeroplane fly? Does the fan or propeller blows the air or sucks the air while flying?

Question

As a layman, I want to know the functions of flop and how does the aeroplane takes off?

Answer 1

Great question, and you have the answer within the question! It's air pressure that allows an airplane to rise into the air. The secret is to get more pressure pushing up than pushing down.

Many years ago scientists discovered that fast moving air exerts less pressure than slower air. So you have to get the air on top of the plane's wing moving faster than the air on the bottom of the wing. How do you do that? Curve the top of the wing! Then the air has to travel farther (to go over the curve), so it's going to go faster. The bottom of the wing is flat - slower air, more pressure up against the wing.

The difference between the two pressures - under and over the wing - is enough to make even a huge 747 go up into the air - if the air is flowing fast enough. That's why an airliner has go almost 200 km/hr (or well over 100 mph) to before it starts to fly

Answer 2

There are four factors that keep an airplane in the air.

1) The shape of the wing. The wings are flat on the bottom and curved on the top, kind of like a Hersey bar. Thus the air going over the top of the wing has to travel further, which means it has to move faster. Faster moving air has a lower pressure. The difference between the high pressure on the bottom of the wing and the low pressure on the top of the wing produces lift.

This website has a diagram showing how this works ...

http://www.geocities.com/galemcraig/

2) The angle of the wing. An airplane does not fly parallel to the ground when it is flying level (not gaining or loosing altitude). When an airplane is flying level it is actually pointed upward slightly. This means that the air is hitting the bottom of the plane and wing and thus pushing it up.

This website has an explanation of this (called the Newtonian or attack angle) ...

http://amasci.com/wing/airfoil.html

3) While all airplane engines suck in air to operate (as does your car engine) this is not what pulls the airplane forward. The engine pushes the air backwards (known as thrust). There is an equal and opposite reaction that moves the airplane forward.

This website discusses thrust ...

http://www.geocities.com/proppitch/Thrust.htm

Now, depending on the angle of the airplane (higher in a climb, less so while flying level) the engine has a slight downward angle, which means that there is a slight downward force. Again there is an equal an opposite reaction, which provides some upward lift to the airplane (again, more when climbing, less when flying level).

4) The trailing edge of the wing (the rear facing edge) is angled down (see angle of attack in # 2 above). Thus the air comes off the wing at a slight downward angle. Again, there is an equal and opposite reaction which provides an upward force.

This becomes more obvious when the airplane is landing, and has its flaps extended. The flaps provide even more of a downward angle to the trailing edge, which provides a greater downward thrust of the air leaving the wing, which provides a greater upward opposite force to the wing and thus the airplane.

This website has a photo of an airplane with its flaps extended ...

http://en.wikipedia.org/wiki/Flap_(aircraft)

Here are some other photos of a planes with the flaps extended for landing (and yes, the photos are real - the airport is on the island of St. Martin/St. Maarten) ...

http://images.google.com/imgres?imgurl=http://www.bookofjoe.com/images/0201517.jpg&imgrefurl=http://www.bookofjoe.com/2006/07/16/index.html&h=358&w=531&sz=43&hl=en&start=0&um=1&tbnid=hA-r4KNuv-gwaM:&tbnh=89&tbnw=132&prev=/images%3Fq%3Dairplane%2Blanding%2Bat%2BSt.%2BMartin%26svnum%3D10%26um%3D1%26hl%3Den%26client%3Dfirefox-a%26channel%3Ds%26rls%3Dorg.mozilla:en-US:official%26sa%3DN

http://images.google.com/imgres?imgurl=http://www.aviationpics.de/prev/st%2520maarten.jpg&imgrefurl=http://www.x-plane.de/forums/lofiversion/index.php%3Ft1953.html&h=385&w=572&sz=86&hl=en&start=0&um=1&tbnid=-fQ9KtqSw-XeqM:&tbnh=90&tbnw=134&prev=/images%3Fq%3Dairplane%2Blanding%2Bat%2BSt.%2BMartin%26svnum%3D10%26um%3D1%26hl%3Den%26client%3Dfirefox-a%26channel%3Ds%26rls%3Dorg.mozilla:en-US:official%26sa%3DN

Answer 3

All wings (and propellers) require an "angle of attack" to generate significant lift (or thrust). A propeller is just a series of spinning wings. Airplanes fly with their wing surfaces angled upward. This creates a high-pressure zone underneath the wing, and a low-pressure zone on top of the wing. The imbalance in pressure on either side creates a net upward force (or a forward force in the case of a propeller).

However, as the angle of attack increases, there will be a point of maximum lift. If the angle of attack increases more, the wing will "stall" (the flow will become turbulent), and lift will be drastically reduced.

The Bernoulli effect is only a small fraction of what generates lift force. If you flew a 747 with its wings at zero angle of attack, the Bernoulli effect would not be enough keep it aloft.

Answer 4

airplanes fly because of the bernoulli principle - by the wing design the wind blows faster across the top than it does the bottom and this makes greater pressure on the bottom of the wing than the top forcing the wing and the plane UP

Answer 5

i can't explain the whole working of how aroplane fly but i can explain the basic principle involved in it
The big turbines in aeroplane sucks the air after that it is heated and compresed after all this air comes out of them with very high speed which makes aircraft to move and fly