How Does Lift Work? (How Airplanes Fly)

Flight has a long and interesting history. At first, people thought it was the feathers on birds that gave them the ability to fly. People even tried sticking feathers onto their arms in order to fly! Needless to say that didn't work. There have been hundred of flying contraptions designed since, including Leonardo da Vinci's 'Ornithopter' in 1485. In 1905 the Wright brothers pioneered and manufactured the first motor powered aircraft - fast forward over 115 years later and we're able to sit in flying structures that travel at 85% the speed of sound and take us around the globe.

Lift is the key enabling force in flight. Lift is made up of two components. Angle of attack, and a pressure differential. The angle of attack is simply the angle between the wing and the horizontal. A large angle of attack will push air downwards, and consequently the air pushes back on the wing, moving it upwards. Too large an angle however can cause the wing to stall and lose lift.

A pressure differential is created by the wing having a highly curved surface on the top side. This squeezes the air and causes it to travel faster. Faster moves air has a lower pressure, meaning the wing is 'sucked' upwards, creating lift.

Wings are highly optimised for specific applications which is why there are hundreds of types of wings in nature and our industrial world!

Song: Joakim Karud - Lowrider (Vlog No Copyright Music)
Music provided by Vlog No Copyright Music.

[Arnostic]

I don’t care how many times I see an airplane takeoff, it’ll never cease to amaze me in every way possible.

[gengiz]

Every time I fly I am amazed at human engineering and technology

[Anthony-gqdk]

The angle of attack on takeoff of the last 380 seems to defy all laws of physics. Looks as if it is about to stall, but doesn't . Great videos, well done, so informative .

[snuggles]

I watched that video twice, and I still do not understand. But don’t worry I was never really good at maths and science.

[ravindupererawarnakulapata]

Really slick explanation (you had 6 mins to sum up a 4-year uni degree!). Also love the Dumbo reference haha!

[stinger]

I live near an airport so ive seen thousands of planes taking off or coming in for a landing. Every single time im amazed.

[Observer]

This isn’t the worst explanation of the physics but still has Two SERIOUS errors.
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@1:45 The elevator surfaces are not called “rear flaps”. Flaps are on the wing.
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@ 2:22 Saying that AoA and Pressure differential is not a bad simplification / summary, but implies there are two lift forces.
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@ 2:48. Air does NOT bounce off the lower surface. It flows downward in a smoothly curved flow. Even MORE air flows curved downward from ABOVE the wing than below.
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@ 3:20 The top-Bottom pressure is ALL the lift. However, a pressure difference will only MOVE the object if it is free to move. A craft in level flight is not “moved” upward by lift.
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@ 3:51 The Coanda effect does lower the pressure near the surface of an inside curve, but Coanda is only for a jet of fluid in an otherwise still environment. This does not happen above a wing. However, the similarity is the lower pressure on the inside of the curved FLOW. Making them easy to be confused.
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@ 4:15 The first serious error. The flow is Not squeezed. There is no hard wall above the wing, but a soft cushion of air. It is NOT a venturi tube. This is one of the common misconceptions.
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Fluid has mass and a net force is created by a pressure difference between two locations – called a Pressure Gradient. Euler first recognized this in the mid 1`700s following up on Bernoulli’s work. That net force Accelerates the mass of air away from the higher pressure toward the lower pressure.
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A Pressure Gradient provides the force that Accelerates air toward the lower Pressure.
The air speeds up because the pressure ahead of the wing is roughly atmospheric pressure which is greater than the reduced pressure above the wing. This pressure is reduced because it is on the inside of the curved flow – It wants to go straight, per Newton’s First Law. You can view it as it is the inertia “pulling away” from the center like you feel moved to the outside car door in a turn. Read Newton’s First Law.
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@4:50 The second serious error. The “faster air” out of the blower is NOT at a lower pressure than the still air around it. This is well known by aerodynamicists and easily measured by anyone with simple equipment. It _is_ the true Coanda Effect creating a centering force by lowering the pressure more when more air curves around one side – allowing the higher air on the other side push the ball back in.
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The pressure inside the blower is higher than atmospheric pressure. This creates an Euler Pressure Gradient which accelerates the air away from higher pressure inside the blower to the relatively lower atmospheric pressure outside where the moving air assumes the atmospheric pressure of the still air around it. Euler again.
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The video does not make it clear that while there are the two things that are significant for lift, it FAILS to clearly state that the entire lift is from the Top-Bottom Pressure Difference. Those pressures are in effect, created by the curved flows below and above which the angle of attack contributes to.

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Regards.

[louisacquah-baidoo]

I wish I could personally give you a 1K like. Your explanation is really indept and same time soo simple to understand

[syedghalib]

Flaps are not moved during run ups, they are set to a certain degree based on passenger/cargo load, the temp of the day, humidity and the runway length, prior to start of run during the take off procedure call. The pressure difference on upper & lower wings are due to the venturi effect. The air flowing past and over the wing does not stick till the end, it detaches itself before the trailing edge. The upper area of the wing near trailing edge which has no air contact is called "wake area". It is not a desirable condition though. So, vortex generators are installed on upper wing to have air in contact, no matter it is not as smooth as the air on front upper area of the wing. The lift formula has no place for wing (aerofoil) thickness. The aspect ratio or the length x width is the one that has significance. Modern jets have thicker wings for structural strength as they are also used as fuel storage. When flaps are deployed, it is the aspect ratio that increases, thus creating more lift.

Venturi effect can be tested by holding two pages, an inch apart, near your face and blowing in the gap. You wil notice that the two pages do not expand apart as you may have guessed, instead they come close like sticking together. Same effect can be seen when a truck or high speed car crosses your motorcycle or car, you feel the magnetic effect of leaning or moving towards the other vehicle. Keep this in mind and be careful on highways.

[theKhumbaguy]

That hair dryer example is amazing.
Great video.

[AL-jnmn]

This is a great video in explaining aerodynamic concepts relating to lift, thank you! It was great to see all the diagrams and the visual representation of the airplane flying because it gave me a better understanding how lift works and how we have to apply the concepts such as the angle of attack and the pressure differential on how faster moving air applies less pressure which are crucial concepts in understanding how lift generates.

[avinashpatil]

I am 63 now today as on August-2024 still have curiosity to see how planes taking off or lands. Every single time I m amazed. Like child, I took window seat to look down the earth surface and observe the wings movements carefully.

[pentogram]

The elevators should have been talked about and how they helps point the nose up after 300 klm

[AndrewCampbell-utjk]

Good basic explanation of how wings work, one of the best I have seen without getting too technichnical.

[AJLKS.]

Very informative! Perhaps one topic to discuss in the future would be "wing aspect ratio"?

[asamapearl]

Love it! Where were you when I was doing my GCSES?

[TheBondy]

Loved all those real life examples of the physics! I wish I was shown this in uni!!!

[aurorap]

Awesome video! Can't wait for the next one. Would love to know more about the history of flight (and how all this was discovered!) in a future video.

[natahx]

Awesome video! I love people explaining aviation concepts! Keep it up <3

[daviddilley]

Oooh, I dunno about this…my flt instructor told me it was all Magic ! And if I didn’t buy him bough beer, he’d put a spell on my plane so it couldn’t come back down….scary…