How does a plane fly?
Otherwise, it is considered a big advantage in just a few hours. A privilege that only a century has passed since its creation. Inspired by nature, mankind has been thinking of inventing a tool to achieve the dream of flight since centuries ago. So that in the past, many people were trying to achieve the dream of flying by using designs similar to the wings of birds. Finally, after many years, the Wright brothers succeeded in inventing the airplane, an event in which they did something that today nearly 10,000 airplanes take to the sky in America alone in one day. The airplane is certainly one of the greatest human achievements.
But how does a plane fly?
If you think that the main reason for the airplane to fly is its engine, you are very wrong, because many flying devices such as gliders or even paper airplanes fly easily without an engine. Aircraft engines provide power for forward movement, but do not lift the aircraft off the ground. These are the wings that create the pressure difference necessary for the plane to take off from the ground. With the increase in the power produced by the engines, the air flow quickly hits the wings and by using the aerodynamic features, the necessary pressure difference is created by the wings for the plane to take off. But how does this happen?
By doing a very simple experiment, we can easily understand why the plane flies. Place a sheet of paper according to your mouth and blow on the upper surface. By blowing air on the paper, the air pressure above the paper is reduced and as a result the air pressure at the bottom of the paper is greater than its pressure at the top and due to this pressure difference, an upward force is applied to the paper and lifts it up. .
So easily by using this knowledge, scientists were able to design the wing of the plane and the plane has the power to fly.
Airplane wings have a curved upper surface and a smoother lower surface. This mode creates a shape called an aerodynamic section (Airfoil).
Imagine that two air molecules reach the front of an airplane wing and separate. One of these molecules is thrown upwards and the other remains slowly on the floor. These two molecules must reach the end of the wing at the same time. As a result, the air above the wing has a higher speed than the air below the wing and causes a pressure difference at the top and bottom of the wing and creates a net upward force. This force can even exceed the gravitational force on the plane and move it upwards.
Now let’s define the main forces entering the plane:
Lift: The force created by the impact of the air with the upper and lower surfaces of the wing and causes the plane to rise or continue its flight.
Drag: It is a force that resists the movement of the plane while advancing.
Thrust: It is the force that drives the plane forward, which is provided by the engines.
Weight: It is the gravitational acceleration applied to the mass of the plane by the earth and pulls it towards itself.
These are the four main forces entered into the plane, the flight of the plane depends on their performance: Weight, Thrust, Drag and Lift. The force of gravity opposes the lifting of anything from the ground and its flight. Propulsion or thrust also comes from the very fast rotation of the airplane propeller or in jet engines, from the expansion of the gases caused by combustion and the rotation of the turbine blades, which has the task of pushing the plane forward. In fact, this is the same power that household fans produce. The drag force or resistance is applied to the plane in the opposite direction of the propulsion force and pushes it back. If you put your hand out the window of a moving car, the air resistance that pushes your hand back is the drag force. But the fourth force is the force that pushes the plane straight up and makes it fly. This force is so strong that it can lift a monster like Boeing 747 with more than 370 tons of weight from the ground.
In a smooth, direct and non-accelerating flight, all 4 mentioned aerodynamic forces are in balance. This means that the opposing forces are equal to each other 2 to 2. That is, Thrust equals Drag and Lift equals Weight.
In this article, we tried to explain how the plane flies in the simplest possible way. In the next issue, we will discuss how to guide and control the plane.
Seyyed Hamid Grossi
Vice President of Daneshbanian Camotech Flight Company
very nice