If you can switch between countries and continents in a matter of a few hours, the credit goes to the aviation industry. But how do the heavy and large airplanes fly so high in the sky? How can they cover thousands of kilometers through the clouds? 

Credits: Shubham Madankar

Aeroplane Engines

The airplanes must stay in a specific altitude range while flying because of a few factors like the type of aircraft, the distance to your destination, the type of engine they possess, the power of the winds, and the weight of the aircraft.

The greater aircraft climb, the thinner the atmosphere gets, and the more efficiently they can fly because of limited resistance in the atmosphere.



A plane's engines are designed to move it forward at high speed. That makes airflow rapidly over the wings, which throw the air down toward the ground, generating an upward force called lift that overcomes the plane's weight and holds it in the sky. So it's the engines that move a plane forward, while the wings move it upward. Aerodynamics, the study of flight, is based on four basic forces namely lift, weight, thrust, and drag and the interaction of these forces explains the movement of airplanes as they make their flight in the sky. 


Forces Acting on Plane

The first force, lift, pushes up on things and the shape of the wings on an airplane creates lift as they move through the air. The second force is the weight that pulls us towards the center of the earth, and why things fall. 

The third force is thrust which is created by the propellers of an airplane and it pushes things that are flying. The fourth force is a drag. It pushes against things moving through the air and is caused by air particles bumping into the object. Any object that is moving quicker bumps into additional air particles, and so experiences more drag. 

When the acting forces are unbalanced, airplanes speed up, slow down, or change direction. This is known as acceleration. Say for example, when the thrust force is greater than the drag force, an airplane speeds up. When the lift force is greater than the weight force, the airplane goes up faster.

Credit: Nasa


When forces are balanced, objects do not undergo acceleration. An airplane that is flying in a straight line at a specific speed has balanced forces. An airplane can even go up or down and have balanced forces. As long as the airplane is not turning, speeding up, or slowing down the forces are balanced.

Pressurized Cabin

Another interesting part of the plane is pressurized cabins. The airplane cabin is more than what it seems. Air pressure falls with height above Earth's surface—that's why mountaineers need to use oxygen cylinders to reach extreme heights. The summit of Mount Everest is just under 9km above sea level, but jet planes routinely fly at greater altitudes than this and military planes have flown almost three times higher! That's why passenger planes have pressurized cabins: ones into which heated air is steadily pumped so people can breathe properly. Military pilots avoid the problem by wearing face masks and pressurized body suits.

Pressurized Cabin
Source: monroaerospace.com