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How Does an Airplane Fly?: A Scientific Explanation of Flight Dynamics

Jagatheesh is a Mechanical Engineer and interested in writing on science and technology in our life.

This article will breakdown the science behind flight dynamics.

This article will breakdown the science behind flight dynamics.

Have you ever thought about how an airplane fly?. Well, the answer is simple, the airfoil shape of the wing and Newton's third law of motion are responsible for the flight of an airplane. Airplanes are truly an engineering wonder in our life.

Airplanes revolutionized the transport system around the world. When the Wright brothers tested the modern plane, they ended the thirst of humanity to fly. Our life is somehow connected with the airplane in one way or another, and this article is all about the science behind airplanes.

Science behind an airplane

There are three basic concepts behind an aircraft they are,

  • Airfoil(Aerofoil) shape: An airfoil is a specific shape that creates an aerodynamic force. The aircraft wings are designed on the airfoil concept. When an airfoil shape object moved at high speed, it creates a force perpendicular to the airflow.
  • Bernoulli's Principle: It states that an increase in velocity will decrease the pressure in a fluid. The pressure difference between the surface and bottom of the airplane wing creates a lift force. It makes the airplane fly. The airfoil shape is responsible for this pressure difference.
  • Newton's Third Law of Motion: The law states that for every action, there is an equal and opposite reaction. When the wings force the air below, it creates an opposite force that lifts the airplane.

The Airfoil Shape

The Angle of attack is the angle between the oncoming air and the reference line on the airplane wing.

The Angle of attack is the angle between the oncoming air and the reference line on the airplane wing.

The Forces responsible for takeoff

The airplane works with the aid of four forces they are,

  • Thrust: It is the force that makes the airplane move forward on the runway. Airplane engines are responsible for producing the thrust. The magnitude of the thrust depends on the type of engine.
  • Drag: It is the force caused by the resistance of air. When an airplane moves at high speed on the runway, the air blows opposite to it. It creates a force opposite to thrust, and it is called drag.
  • Lift: It is the force that lifts the airplane. The airfoil shape of the wings produces a pressure difference. The difference in pressure between the top and bottom of the wing lifts the airplane upwards.
  • Weight(Gravity): It is the weight of the airplane that pulls the plane downwards. The weight of the machine and cargo determines the magnitude of this force.

Thrust is opposite to drag, and lift is opposite to weight. During take-off, thrust must be higher than drag, and lift must be higher than weight. Once the airplane reaches the required altitude, the forces will be balanced.

To invent the airplane is nothing. To build one is something. But to fly is everything.

— Otto Lilienthal

The Three Axes of Rotation of an Airplane

The aircraft moves in three different axes, they are

  • Pitch- It is the movement of an aircraft nose and tail up and down (Lateral axis)
  • Roll- It is the movement of aircraft wings up and down (Longitudinal axis)
  • Yaw- It is the movement of the entire aircraft sideways (Vertical axis)
The four forces must be equal in the sky for the plane.

The four forces must be equal in the sky for the plane.

Major Components in an Airplane that aids Flying

The structure of the wing and tail in an airplane is responsible for the flight. Numerous components are attached to the wings and tail to aid flying. The major components are,

1.Flaps: Flaps are the high lifting devices on the trailing edge of the wing. They are used to increase the camber and surface area of the wing. It will improve takeoff at lower speed and landing performance.

Note: Camber is the asymmetry between the two acting surfaces of an airfoil. The top surface of the wing will be more convex.

2.Slats: Slats are the high lifting devices on the leading edge of the wings. They increase the lift during low-speed operations like takeoff, initial climb, approach, and landing.

3.Aileron: These are the movable parts in the trailing side of the airplane wings. It permits the pilot to roll the airplane around its longitudinal axis.

4.Spoiler: Spoilers are the small hinged plates on the top portion of wings. It is used to increase the drag and decrease the lift by disrupting airflow over the wings. They play a major role in reducing the speed and aiding the descend. Spoilers are also used to generate a rolling motion.

5.Elevator: Elevators are the panels on the tail of an airplane. They control the airplane on its horizontal axis. Elevators control the position of the nose and angle of attack of wings.

6.Rudder: Rudder is the movable component on the trailing edge of the fin. It controls the plane on its vertical axis. It controls the plane when an engine fails. Rudder controls the position of the airplane nose.


How does an Airplane Fly?

When the plane moves at high speed on the runway, the wing which is in the shape of an airfoil produces downwash. It creates a pressure difference between the top and bottom of the wing. High pressure is created below the wing and low pressure is created on the top of the wing. This pressure difference will lift the airplane. Flaps and slats alter the airfoil shape, thereby increasing the lift.

Ailerons are used to alter the lift force. The elevator and rudder control the vertical and horizontal force. During takeoff, the elevator moves upward. It increases the tail force and makes the tail tilt. For takeoff, thrust must be higher than drag, and lift must be higher than weight. When the plane reaches the required altitude, all four forces are balanced.

How does an airplane change its direction?

The aileron and rudder are used to change the direction of the plane. A centrifugal force is needed to turn the flight. One aileron is raised, and the other is lowered, which produces a difference in lift. The difference in the lift force makes the airplane roll.

The lift force is not vertical, so the horizontal position creates the necessary centrifugal force. But the drag force in the plane will not be the same, which creates a twist called yaw. Rudders and aileron can control the yaw.

During descend, the thrust from the engine is reduced to increase the drag. Slats and flaps can also increase drag. During landing, drag will be more than thrust, and weight will be more than lift.

Airplane connects the world

The modern world is connected with communication and transportation. Airplanes are a major invention that changed the face of travel. With the planes no distance in longer. Cargo planes connect Washington berries to a consumer in Sydney. Airplanes have ended the quest of mankind to fly. Let's fly more to explore more.


This content is accurate and true to the best of the author’s knowledge and is not meant to substitute for formal and individualized advice from a qualified professional.

© 2021 Jagatheesh Aruchami


Jagatheesh Aruchami (author) from Coimbatore, India on June 02, 2021:

Thank You! Eman Abdallah Kamel for reading this article.

Jagatheesh Aruchami (author) from Coimbatore, India on June 02, 2021:

Thank you! Liz Westwood, for your comment. I'm glad that this article helped you to learn about Airplane.

Eman Abdallah Kamel from Egypt on June 01, 2021:

Thank you for this informative article about Airplane.

Liz Westwood from UK on May 30, 2021:

This is a very well-presented and well-explained article. I have learnt a lot about this amazing mode of travel that we often take for granted.

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