Each day, roughly 130,000 flights take off and land around the globe. With modern technology, planes can fly at average cruising speeds of 500 to 600 miles per hour, allowing passengers to be transported thousands of miles in only a few hours. Yet, a century and a half ago, air travel was merely a concept of the future and the science behind it was an enigma.
Although Wilbur and Orville Wright were the first people to create a working aircraft, the study of aerodynamics started much earlier. In the 1480s, Italian inventor and artist Leonardo da Vinci created over 200 sketches of an ornithopter flying machine to illustrate the potential of human flight using planes that mimicked bird wings. Isaac Newton contributed to the understanding of drag and Bernoulli discovered the relationship between velocity and pressure, according to Britannica. Building on these foundational principles, modern aviation relies on a comprehensive understanding of aerodynamics and the forces of flight.
The four fundamental forces of flight are lift, thrust, drag and weight, according to NASA. Lift, the upward force on the airplane, is generated by the airflow above and below the plane’s wings. Weight, in contrast, is the force of gravity pulling the airplane downward. Because planes fly through air, a fluid, they experience air resistance called drag. To push the plane forward, thrust is produced by the plane’s engines. In order to have a successful flight, pilots must ensure thrust overcomes drag and lift supersedes weight.
But, how do planes generate this lift and thrust? In the world of aviation, one of the most important principles of flight is the Bernoulli Principle. This principle states that pressure decreases as the velocity of a fluid flow increases, according to Stanford University. In aviation, all planes are optimized to decrease air flow velocity under the wing and increase air flow velocity above the wing. As a result, this difference in pressure around the wing leads to a high pressure zone below the wing and low pressure zone above it, generating lift.
To achieve this, the airplane’s wing—the airfoil—is designed to allow air to flow at different speeds above and below the wing. The “leading edge” of the wing forces air to speed up as it flows over the curve, creating an area of lower pressure above the wing. Near the wing tip, the airflow rejoins again, creating downwash. According to Newton’s third law, the equal and opposite reaction to this downwash is an upward force on the aircraft, also creating more lift.
Pilots must be able to take advantage of these forces to control the angle of flight, speed and direction of the plane. This is achieved through various control surfaces on the aircraft, including ailerons, elevators and rudders. On the wing of the plane, ailerons allow the plane to roll from side to side by changing the “angle of attack” of the airfoil. Elevators, located on the tail of the plane, allow for pilots to control pitch (to descend or climb). Finally, the rudder moves the plane around its vertical axis, allowing it to yaw left and right. When used with coordination, pilots can use the rudders, ailerons and elevators to maintain straight flight, make smooth turns, navigate crosswinds and take-off and land.
In addition to basic flight controls and aircraft parts, modern advancements in aviation technology are introducing new features and innovations to enhance flight control and efficiency. Fly-by-wire systems, for example, replace traditional manual flight controls with fiber optic systems, allowing for improved performance and less weight, according to NASA. Advanced materials such as carbon fiber composites are now used in aircraft construction, making planes lighter and more fuel-efficient. Furthermore, advancements in artificial intelligence have led to better unmanned aircrafts and alternative fuels have made flying more sustainable.
The journey from early aerodynamic discoveries to the commercial, military and industrial aircraft used today is a testament to the human ingenuity required to build such a machine. Flying is no small feat, but understanding the fundamental forces of flight, principles of airflow and capabilities of the plane has made modern aviation much more efficient and reliable. Although flight was once a human aspiration, the work of influential scientists, such as Da Vinci, Newton and the Wright Brothers, has made it possible for present-day engineers to take to the skies. Today, aviation is not just a means of transportation, but a symbol of human achievement and progress, connecting people and cultures globally. In the future, everyday planes may evolve into supersonic jets as engineers continue to push the boundaries of technology and pilots push the boundaries of flight.
