Tag Archives: drag

How do Airplanes fly.?

Basic forces in Airplane
Basic forces in Airplane

Airplanes! One of the greatest inventions of all time by our great Wright brothers. Lots of things that go up in the air don’t have the capability to stay there because gravity overtakes them. But how about this airplane? It does make you wonder how it is possible for such a massive objects to soar through air.

I’m taken back to my childhood times where I come rushing up inside my home when I hear the noise of the airplane just to glimpse at it with no idea of how it works. This being my favorite topic of all I’m more interested to tell you how these giant machines take to the air.

The Four Arms:

When it comes to airplane, there are four different forces that act on it, each force pushing from a different direction.

  • Lift
  • Weight
  • Thrust
  • Drag

Lift and weight are the upward forces and downward forces while thrust and drag are the forward and backward forces .In order for an airplane to make its flight thrust and lift forces are very essential. This implies that forward and upward pulls must be stronger than the backward and downward pulls.


The most significant force when compared to the other three forces. Most of us would have been known that the airplane wings have a flatter lower surface with a curved upper surface, giving a cross sectional shape called the aerofoil. Special thanks to the curved shape of the airplane’s wing because it is the aerofoil that allows the airplane to lift up, up and up!

A simple and basic theory of physics called Bernoulli’s law works here.

As air hits the wing in flight, it is split into two where one part moves over the wing and the other part travels under the wing. Since the top of the wing is designed with more curve than the bottom of the wing, the air moving on the top of the wing travels faster than the air moving underneath the wing. Similarly a region of high pressure is created below the wing and low pressure above the wing.

It is a known fact that air moves from a region of high pressure to low pressure. Therefore air moves from bottom of the wing to the top thus creating the lift force that holds the airplane up in the sky overcoming its weight.

Lift can be produced by any part of the airplane but the maximum amount of lift is created by the wing section.


Lift’s opposing force is weight. It acts in the opposite direction of the Lift force. Weight is usually created by the natural pull of gravity towards the center of the earth. Airplanes are built in a way that their weight is spread from front to back so that it keeps them balanced. To feel the effect of this force jump up from the chair. Your weight will force you back down to the floor.


Thrust is the forward pull of an airplane. The engines take up the job of creating thrust here. Sometimes it is the engine that turns a propeller. Sometimes it is a jet engine. For an airplane to fly, it should get more forward push from the engines than the backward push which is received from the air in front of it.


The enemy of an airplane is the Drag force. The opposing aerodynamic force of thrust is the drag. It resists the motion of an airplane in moving forward. To experience this simple demonstration of drag force, just stick your hand out of the moving car window.

So hope you all got a clear picture of how the airplane takes its flight. So it’s the engine that moves the airplane forward and the wings make it move upward.

Hope the next time when you get to see a Boeing 787 you will be secure in knowledge what is lifting the airplane into the air. So it’s the four arms that hold the airplane in the air, each pushing from a different direction. But, most of the airplanes do need one more thing. They need a pilot to fly them too!