MVP ARCHIVE | History of Flight Special 05 : The Science of Flight / How Air Lifts Wings

Airplanes are supported by air

An airplane cannot fly with engines alone.
It cannot fly with wings alone either.
What makes flight possible is the flow of air.
Invisible air changes its flow depending on the shape and angle of the wings, creating the force that lifts the aircraft.
Aeronautical engineering is also the technology of understanding and utilizing the fluid known as air.

What happens around the wings

As an airplane moves forward, air flows over and under the wings.
Wings have a special cross-sectional shape (airfoil), and that shape changes the flow of air.
Air flows faster over the top of the wing and relatively slower underneath.
At the same time, the wing pushes the air downward.
This pressure distribution and the change in the direction of the air create an upward force on the wing, known as lift.

It is not just Bernoulli's principle

In the past, the explanation that "wings fly solely due to Bernoulli's principle" was widely known.
However, it is now understood that the mechanism of flight cannot be explained by a single law.

Wing shape. Angle of attack. Changes in air pressure. The flow that bends air downward.
The viscosity of air. The circulation formed around the wing.

As these factors influence each other, a pressure difference is created between the top and bottom of the wing, generating stable lift.
Bernoulli's principle is an important law that explains the relationship between pressure and flow velocity.
However, it is now positioned as one element for understanding the behavior of the fluid as a whole, rather than the entire mechanism that generates lift.
Modern aeronautical engineering understands the mechanism of flight by combining multiple fluid phenomena.

Angle of attack and stall

Wings cannot fly the same way at every angle.
By maintaining an appropriate angle relative to the air, a stable flow is formed, and sufficient lift is generated.
However, if the angle of attack is increased too much, the flow around the wing becomes turbulent, and the boundary layer separates from the wing.
As a result, lift is lost rapidly.
This is a "stall".
A stall is not simply a matter of slowing down.
It is a phenomenon that occurs when the balance of the flow maintained around the wing is disrupted, making it impossible to maintain a stable flow field.

Designing invisible air

In aircraft design, the flow of air formed around the wings is more important than the wings themselves.
Wind tunnel experiments. Computational Fluid Dynamics (CFD).
Simulations using supercomputers.
Modern aircraft achieve faster, farther, and safer flight by designing the entire flow of invisible air.

Legacy

For a long time, humanity dreamed of flying by watching the wings of birds.
However, what we really needed to understand was not the birds, but the air itself.
The history of aviation is the history of inventing airplanes, but it is also the history of understanding the fluid known as air.
For a single wing to fly, the wing alone is not enough.
Stable lift is generated when the entire flow of air formed around it maintains balance.
That understanding continues to advance even now, and is being passed on to the design of new aircraft and spacecraft.