Most travelers have wondered during a flight how on earth this enormous, hulking thing manages to stay up here while gazing out the window.
The short answer is engineering magic, which uses Newton’s Third Law and variations in air pressure to produce enough lift to overcome the force of gravity.
Please read on for more detailed information.
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How Do Planes Stay in the Air?
Air is directed downward when it passes over any flat plate at an angle, such as when you hold your hand out of a moving car window.
Newton’s Third Law states that when the air pushes back up on your hand, you have lift. Up to a point of failure known as a “stall,” the lift (coefficient of lift, Cl) increases with increasing angle, or “angle of attack,” but since we’re talking about how planes stay aloft, we can ignore that.
For more lift, you can fly faster (Velocity, V). And how much is it for those who want to learn more about the science? Exactly this much.
If you did hold your hand out the window, you would quickly notice how much drag was being created by the air pushing back on your hand.
The secret (and it also helps to have a degree in aeronautical engineering) is to maximize lift while minimizing drag (Lift to Drag ratio). If you don’t, you’ll need a lot of fuel to get anywhere, which adds weight, which forces us to fly faster, which burns fuel faster—you can start to see the circular nature of this issue.
This is where the airfoil’s curved profile comes into play. These profiles are applied to all wing surfaces, generating lift by smoothly guiding air over the upper and lower surfaces.
The pressure decreases (Bernoulli Effect) and the air speed up as it passes over the top of the surface (Venturi Effect). The free stream air above the wing then pushes down on the flow and “attaches” it because it wants to equalize the pressure close to the wing surface (Coanda Effect). We get a stalled wing if the angle becomes too great because there is not enough pressure to keep it attached.
Can Planes Stay in the Air Without Moving?
Theoretically, an aircraft could remain airborne for an extended period of time.
The two opposing sets of forces must be equal in order for the plane to remain motionless in the air, i.e., lift must equal weight, and drag must equal thrust.
A plane could only remain in the air motionless for a short period of time in reality, and even then it’s extremely uncommon.
An airplane needs to move forward to maintain flight because it cannot generate lift while at rest.
Due to a lack of lift, a plane that remains in the air would eventually fall from the sky.
How Do Planes Take Off?
An airplane’s engine propels it at a high rate of speed, creating airflow over its wings.
When air passes over a plane’s wings and toward the ground, lift is created.
A plane can move upward using lift, while forward motion is made possible by thrust.
An airplane can take off when it moves quickly both horizontally and vertically.
How Do Planes Land?
When an aircraft lands, it descends by decreasing thrust and lift.
In order to reduce aerodynamic drag and increase lift, the plane’s wings change shape.
This causes the plane to descend.
To further reduce lift and allow the rear landing gear to make contact with the ground, the aircraft also adjusts its pitch to a nose-up position.
So, How Do Airplanes Stay in the Air?
- By controlling the forces pulling on them, planes manage to stay in the air.
- Ailerons on a plane’s wings can be adjusted to increase lift, which allows for climbing.
- Increasing the thrust from an aircraft’s engines allows it to fly faster.
- In order to slow down and descend, planes also reduce thrust and the lift that is exerted on them.
- Theoretically, if all opposing forces acting on an airplane were equal, the airplane could stay still in the air. However, given that planes need lift to stay in the air, this is a highly improbable scenario.
- As well as increasing thrust and increasing lift with wing adjustments, airplanes can climb.
- A plane can take off from the ground thanks to the interaction of increased forward motion and increasing lift.