By Dhruv Varma
Airplanes! Aren’t those the giant metal tubes carrying hundreds of people, thousands of feet above the ground? Have you ever wondered how they can perform their flight, especially when they weigh thousands of tonnes and still manage to stay afloat? I have the answer for you.
A typical airplane’s wings and tail are not made in a single piece but in many movable parts which form a very special shape called ‘Aerofoil’.
This Aerofoil design causes lift on the airplane’s wings by producing a downwash; this results in pressure differences above and below its surface. The low speed, high pressure wind below the wings pushes the wings to the high speed, low pressure area above it.
Lift can be increased by three main factors :
Increase in speed
Increase in angle of attack
Use of flaps and slats
Extended flaps and slats will increase the Aerofoil effect, thereby increasing the lift.
What happens during the take-off?
During the take-off, the airplane’s engines provide an extremely high speed. The elevators at the back of the airplane move upwards to increase the angle of attack. Flaps and slats are also extended. This provides a huge force of lift that overcomes the airplane’s weight, i.e the gravitational force acting on it. Thus, the airplane climbs in the air and commences flight.
-Elevators, Ailerons and rudder (Credits: During the cruise)
In the duration between the climb and reaching the flight level altitude, the force of lift is kept more than the force of drag by the elevators controlling the angle of attack, and by the flaps and slats that are now retracted. This is called pitch and results in constant acceleration of the airplane body. However when the airplane reaches its flight level for cruising, the lift is kept the same as the drag acting upon it so that it floats smoothly.
How to turn the airplane
The turning effect on the airplane is known as Yaw which is controlled by the rudders (picture is above for reference). They turn left or right according to the direction the airplane wants to go. However, if the Yaw is performed directly it can make the passengers uncomfortable by the jerky movements. So, the ailerons will be used to roll the airplane to give a smoother turning effect.
Finally the landing
In the landing, the lift is reduced by doing the exact opposite of the procedures followed in the take-off – reducing speed and angle of attack. However, the flaps and slats remain extended. Spoilers are deployed which will increase the aerodynamic drag. Lastly, when the plane touches down on the runway, the engines reverse thrusts (they let out air in the opposite direction), acting as the brakes on the runway.
-Airplane spoilers (source: Quora)
-Reverse thrust (source: Wikipedia)
I hope you all enjoyed this journey of learning the beautiful phenomenon of the flight of an airplane.
Bibliography:
Picture sources:
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