How does a jet aircraft fly?

These jet aircraft are larger, faster and have greater range, compared with propeller-driven aircraft.
FILE - An image of the Boeing 737 Max jet, used for representational purposes only. (Photo | AP)
FILE - An image of the Boeing 737 Max jet, used for representational purposes only. (Photo | AP)

It was on the morning of December 17, 1903, when brothers Wilbur and Orville Wright, who spent four years devising the first successful powered aeroplane -- the Wright Flyer -- presented to the world one of the greatest inventions of all time, 'Powered Flight'. With Orville at the controls, the heavier-than-air Wright Flyer took off at Kitty Hawk, North Carolina, in the US, and flew for just 12 seconds, travelling 120 feet, and reaching a top speed of 6.8 mph. Since then, powered flight (involving aeroplanes) has revolutionised how we travel and how wars are fought. So how does an aeroplane fly?

Today, we are way into the Jet Age. Most aircraft we see parked at airports or crisscrossing the sky above are powered by noisy jet engines, usually attached to the wings. These jet aircraft are larger, faster and have greater range, compared with propeller-driven aircraft.

There is a common misconception that it's the engines which solely aid a plane in flight. In fact, a plane takes to the air, due to specific roles being played by the engines and the wings, supporting each other. 

There are 4 forces at play:    

Lift: It is created when air flows over an aircraft's wing (aerofoil). It is perpendicular to the flight path through the wing's centre of lift, and opposes the downward force of weight.  

Thrust: It is achieved when air is pulled in and then pushed out in the opposite direction (through the engine), thus moving an aircraft forward.

Drag: It resists the movement of an aircraft through the air.

Weight: It is the force with which gravity attracts a body (in this case an aircraft) towards the centre of the Earth.

The above forces work together to achieve aerodynamics, which is an aircraft's ability to move through the air. Newton's third law of motion, 'For every action, there is an equal and opposite reaction', explains how the engines and wings work in tandem, enabling an aircraft to move through the sky.

The force of the hot exhaust gas shooting backwards from the jet engine pushes the aircraft forward, thus creating a moving current of air over the wings. The wings are designed to rapidly push that air downwards, in turn powering the plane upwards, taking off into the sky.

During this time, the force from the engine thrust exceeds the drag, which is attempting to pull the plane back down. When a plane flies horizontally at a steady speed, lift from the wings balances the weight of the plane, while the thrust balances the drag, and the plane is in flight.

To descend, a pilot reduces a plane's lift slightly, by decreasing thrust and increasing drag, which allows the plane’s weight to bring it back to the ground, aided by gravity.

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The New Indian Express
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