People have wanted to fly for hundreds of years. There are children that grow up hoping they can fly through the skies one day like a bird. However, in reality, humans can’t fly through the air with ease. So, we came up with a way to get humans into the skies to experience flight.
There are various things and forces that need to be considered to achieve flight. In this piece, I’ll guide you through the two biggest principles.
One of the main principles of flight stems from Sir Isaac Newton’s law that ‘to every action, there is an equal and opposite reaction’. To understand this, let’s first take a look at some other vehicles. A boat on the water that weighs a ton is prevented from sinking from an upward force of the same value. The same applies to aircraft that are in flight. They have a certain weight and need to be countered by a similar upward force to stay in the air.
When a plane is in the sky, it has gravity pulling it back down to earth; this is known as the weight force. The upward force, or ‘lift’, acts against gravity and keeps the plane steady in the air. This upward force is generated by the air. More specifically, it’s generated by air moving under and over the wings. Moving air provides a force on objects, especially when the object is moving at speed. So, when a plane is soaring through the air, the force exerted is great enough to keep it up.
The easiest way to help make sense of this is to imagine cycling on a bike. If you pedal slowly, your hair tends to stay in one place. But, the faster you pedal, the quicker you move through the air. As a result, you find that your hair is blown back and stays stuck up as you pedal faster and faster. This is the air forcing it up and keeping it steady.
Thrust and drag are two other forces that have an effect on aircraft in flight. I just explained how planes need to air flowing over their wings to get that lift force countering the weight. And, to do this, the plane needs to be going at a fast speed. This is where the thrust force comes into play. The engine of the aircraft will provide the thrust to send it through the air. Typically, this is done by jet engines taking in air and firing it backward at extreme speeds forcing the plane forwards.
Then, you have the opposite force to thrust, drag. Drag is essentially air resistance that prevents the aircraft from moving forward. Too much drag will mean a plane is too slow and can’t get the required lift to keep it up. So, more thrust is needed to counter the drag and keep the aircraft moving.
These are the two main principles of flight that you must strive to understand. In short, provide enough thrust to overcome the drag force. Then, you’ll be able to generate enough lift to counteract the weight.