# I never really understood how is it ther airplanes fly?

@shomomo (850)
Israel
April 27, 2007 12:14pm CST
I can understand how helicopters fly, they use propellers in order to get of the ground, but I just don't understand how can airplanes leave the ground? I don't understand.
3 responses
@mvsrao (4367)
• India
27 Apr 07
If you are interested in more information , I'd suggest to look at the details available on www.wikipedia.com or www.howstuffworks.com http://en.wikipedia.org/wiki/Helicopter http://travel.howstuffworks.com/helicopter.htm
@mvsrao (4367)
• India
27 Apr 07
http://en.wikipedia.org/wiki/Fixed-wing_aircraft http://travel.howstuffworks.com/airplane.htm
• United States
22 May 07
According to Newton's 1st and third laws, "a body will remain at rest, or a body will remain in motion unless subjected to an external applied force" (1st law) which means if you notice a bend in air or still air suddenly moves, a force has acted upon it. And "for every action there is an equal and opposite reaction" (3rd law) - so what the wing does to the air (separates it) is the action while the lift (a key element to flight) is the reaction. Basically, this all just describes streamlines. But to create that, the wing must change something in the air to create lift. Changes in the air's momentum will create forces on the wing. To create lift, the wing must force lots of air down. So the lift equals the change in momentum of the air the wing pushes down. The lift of a wing is proportional to the amount of air diverted down TIMES the downward velocity of that air. This is basically just an alternate version of F=ma, or Newton's second law which relates the acceleration of an object (a) to its mass (m) and to the force on it (F). The greater the angle of the wing and the greater the speed, the greater the vertical velocity. It's this vertical velocity that gives the wing lift and allows it to fly.
@uath13 (8207)
• United States
27 Apr 07
Its matter of the wing design. The bottom of the wing is flat allowing the air to pass by quickly while the top is curved which slows the air passing over it down. The difference between the two causes a vacume over the top of the wing which pulls upward on it, this causing lift.