Airplanes are large airborne vehicles which are used commonly in modern time for transportation, research, military, etc. The number of passengers who fly on airplanes have steadily increased. In 2019, the number of flights were 38.9 million, and it is forecasted to reach 34.4 million flights in 2023.
Since WW1 and WW2, aviation has seen consistent developments and technological advancements, not only for war, but for transportation too. They are so powerful that they can carry over 100 passengers to the vast edges of the world. This article will dive deep into the heart of the question: How Do Airplanes Fly?
Forces
To understand how airplanes can fly, we must first look into kinematics and the forces that are applied onto the object. There are 4 forces that can affect an airplane in a perfect scenario: thrust, lift, drag, and gravity.
Thrust
Lift
Drag
Gravity
The force that impacts the plane’s ability to fly the most is its lift. As mentioned previously, the lift is generated by the wing’s specific shape. This shape is called airfoil, a body (such as an airplane wing or propeller blade) designed to provide a desired reaction force when in motion, relative to the surrounding air. What this means is that the airfoil is a specific shape that allows for optimal lift, so that the plane can fly.
Airfoil Design and Geometry
Airfoil geometry and design have been experimented with since the creation of the first airplane by the Wright brothers. But, we can thank Eastman Jacobs from NACA (National Advisory Committee for Aeronautics) in 1939 for the creation of the modern and most common airfoil design. He designed and tested the first laminar flow (smooth movement of fluids) airfoil sections, which greatly decreased the drag and achieved a lift-to-drag ratio (a numerical value that represents how efficient the airplane is in terms of aerodynamics) of 300 (the higher the value, the more efficient).
The top section of the airfoil has a larger surface area, whereas the bottom has a lower one. The top has turbulent flow and the bottom has laminar flow (mentioned earlier). This strategic geometry creates the pressure which allows for lift.
Generation of lift
The higher surface area on the top half creates higher velocity, and the lower half creates lower velocity. That is why the top has low pressure and the bottom has high pressure. Due to the increased pressure in the bottom, it pushes everything to the top, generating lift. However, the amount of lift that is generated must be greater than the force of gravity otherwise it cannot fly. We can mathematically see this value through the Lift Formula.
Works Cited
Airfoil Definition & Meaning. (2024). Merriam-Webster Dictionary. [online] Available at: https://www.merriam-webster.com/dictionary/airfoil [Accessed 1 Jan. 2024].
Airfoil Design. (n.d.). Available at: https://mail.tku.edu.tw/095980/airfoil%20design.pdf.
Mit.edu. (2024). Theory of Flight. [online] Available at: https://web.mit.edu/16.00/www/aec/flight.html [Accessed 11 Jan. 2024].
Statista. (2023). Airline industry worldwide - number of flights 2023 | Statista. [online] Available at: https://www.statista.com/statistics/564769/airline-industry-number-of-flights/ [Accessed 2 Jan. 2024].
The Science Behind it . . . How do airplanes fly? (n.d.). Available at: https://ext.vt.edu/content/dam/ext_vt_edu/topics/4h-youth/makers/files/ww1-science-behind-it-airplanes.pdf.
White, Z. (2023). What is Laminar Flow? [online] Ossila. Available at: https://www.ossila.com/pages/what-is-laminar-flow [Accessed 11 Jan. 2024].
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