May 25, 2023

Understanding The Basics of Flight: How Planes Work & What Makes Them Fly

In the history of mankind, aircraft have achieved incredible engineering feats. High-speed flights, heavy payloads, and precise maneuvers are accomplished by modern aircraft with remarkable control. By capitalizing on specific forces, pilots harness the ability to propel aircraft through the sky in a controlled manner. The vast operational variety of aircraft designs today stems from their distinct aerodynamic, practical, or utility purposes, necessitating different approaches to managing flight principles. With this in mind, we can now work on our understanding of the basics of flight: how planes work and what makes them fly.

The Laws of Motion

To understand the flight of an aircraft, let’s first take a quick refresher on Newton’s three laws of motion. In short, the three laws of motion can be stated as follows:

1. If an object is not moving, it will not start moving by itself. If an object is moving, it will not stop or change direction unless something pushes it.

2. Objects will move farther and faster when they are pushed harder.

3. When an object is pushed in one direction, there is always an equal resistance in the opposite direction.

Now that we have these motion principles in mind, llet’s look at the Four Main Principles of Flight.

The Four Main Principles of Flight

To help you understand the basics of flight, let’s delve into flight principles. We can summarise airplane flight using four main principles: lift, weight, thrust, and drag. These principles represent opposing forces. Weight is the opposite of lift, while drag opposes thrust. Achieving a balance among these forces ensures successful flight. Now, let’s examine each of the four main flight principles in greater detail.

Lift

Lift is the force that pushes the aircraft upwards. The aircraft’s wings are designed to be an aerofoil, which means that the wing’s shape creates an aerodynamic reaction (lift). This component is especially important for flight, so we will cover this more in a moment.

Gravity (Weight)

Gravity is the opposing force to lift, which pushes an aircraft downwards. Gravity’s direction is not merely downward; it specifically points towards the center of the Earth. Additionally, gravity’s influence varies with an aircraft’s size or mass – larger aircraft experience a greater gravitational impact, necessitating more lift.

Thrust

Thrust propels the aircraft forward, differing from lift and gravitational pull as it involves the mechanical input of energy from an engine or turbine.

Drag

Drag opposes the aircraft’s motion, generated by frictional airflow over its surface, hindering flight. If drag has a factor of ‘1’, the aircraft requires more than a factor of ‘1’ in thrust energy to move forward. Air displacement causes the drag force, as the aircraft must push air aside, resulting in a reactionary force in accordance with Newton’s third law of motion.

Exceptions and Considerations to The Principles of Flight

Now that we’ve explained the principles and basics of flight, we know how an aircraft successfully moves through the sky. That being said, the relationship between these forces can be somewhat utilised in different ways.

Take a glider as an example. While it needs initial thrust and energy to reach altitude, it can sustain forward momentum for extended periods by employing various flight techniques to achieve a balance in the principles of flight. This involves utilizing thermals, leveraging gravitational pull for efficient lift, and minimizing drag to generate momentum. Another option is a hot air balloon, which employs thermal energy for lift and relies on wind for momentum.

Wing Design, Aerofoils & Aerodynamics

Although aerodynamics is a complex science, we can simplify the basics of flight for understanding. Aerofoils and wing designs play a crucial role. Thousands of wings, each designed as a different aerofoil, serve various purposes and adhere to distinct aerodynamic principles. Larger wings generate substantial lift, while smaller ones or those designed for high lift have higher drag. These principles are applied in STOL (short take-off or landing) aircraft.

If you can imagine a cross-section of a wing, most of them follow the same flight principle. That is, when air passes over the wing, the air above the wing travels faster and at a reduced pressure, and the air beneath at a slower pace and higher pressure. With low pressure above and high pressure beneath, naturally, there is a want for the wings of the aircraft to go up and equalise these air zones. Now, there is more than one way of explaining this – and it can become a widely-debated topic – but you can understand why the wing causes the aircraft to experience lift.

Control Surfaces and Aircraft Design

Once an aircraft has sufficient forward momentum to sustain the basics of flight, a pilot then has a variety of controls and control surfaces to enable the pilot to manipulate the aircraft’s motion. These controls involve rolls, yaw, and pitch.

1. Ailerons on the wings allow the pilot to ‘roll’ the aircraft left and right, which is useful for turning the aircraft around the front-to-back axis.

2. The rudder changes the yaw of the aircraft from side to side, which assists in rotating the aircraft around the vertical axis.

3. The elevator changes the pitch of the aircraft, up and down, around the side-to-side axis.

Aircraft also can feature additional control elements, such as flaps, to support controlled flight. Flaps, for example, increase the wings’ surface area to produce additional lift. This is useful for exercises like landing so that aircraft can touch down at slower speeds without gravitational forces overcoming flight.

And That’s How Planes Fly!

Congratulations! You now have a solid grasp of the fundamentals of flight, including how planes operate and the principles behind their ability to fly. If you desire a deeper understanding, the instructors at Learn To Fly Melbourne are eager to assist you and can even arrange a trial flight experience.

Are you ready to join the evolving world of aviation?

Chat with one of our flight training specialists to get your pilot training off the ground. Email [email protected] or go to https://drift.me/learntofly/meeting to book a meeting and school tour.

What Else Should I Know?

We’ve compiled a few useful posts that might help you out. Where ever you are on your aviation journey, the team at Learn To Fly Melbourne are here to help. We want you to pass your exams and have an excellent career, so please reach out if we can help support you through your course and studies!