How Airplanes Fly / Explanation of Lift (How It Works!)

Why can airplanes fly? What is the explanation of lift? Several theories will be presented to get a broader picture of the reasons why planes fly around the world.

Contents
1) Karl Wilhelm Otto Lilienthal (Glider King)
2) Wind tunnels with fan systems and nebulizers
3) Bernoulli principle
4) Wake turbulences, circulation and vortices
5) Low- and high-pressure zones
6) Counter rotating vortex
7) Newton’s laws
8) Coandă effect and lift
9) Shape of airfoil, angle of attack and downwash

[anthonymontemayor]

I really enjoyed your video. One of the few videos about lift that mentions circulation. You also did a great job explaining circulation with regards to the starting vortex. Gives a reasoning for why fluid moves faster over the top of the airfoil. There is more than one theory behind lift as well. Conservation of momentum and the deflection of air around the airfoil is a theory in addition to pressure-velocity fields and the circulation that you talked about. Also, Coanda effect is only applicable to jet flows and the air in the atmosphere is a continuum so that effect doesn't apply. Good job overall!

[andreamae]

Thanks for the video! Watching in the year of 2021

[V-ValveSupercharged]

air flow theories are also important in F1 cars because unlike a normal car, an f1 car needs down force to go around a corner fast

[willTryAgainTmrw]

thanks for another nice video, but actually i got confused even more! :/ any literature you would like to suggest?

[ezvqfdt]

I can't believe there's an accurate video explaining the production of lift. It all starts with circulation.

However, you mentioned Newton as if it was its own separate theory. Everything is Newton; it's the basis for physics. In the end, what is important is that the wing is producing downdraft (forcing the air down). If the air is pushed down, the wing, by Newton's 3rd Law, must be pushed up. So, the Bernoulli's Principle comes into play as the air on top of the airfoil speeds up much faster than air on the bottom, thereby creating an area of high pressure on top and low pressure on bottom. Great, but how does that produce lift? The atmospheric pressure above the relatively low pressure on top of the airfoil makes it so that air flows from top toward the wing, and by equal and opposite reaction, the wing must be pulled up toward the low pressure on top. Since the airfoil is moving through the air, the air will rush down toward the backside of the airfoil, creating downdraft. Air moves down, wing moves up. Bernoulli and Newton are not 2 separate theories: Bernoulli, in the context of explaining lift, merely expands upon how Newton 3rd law comes into play. Newton's theory of lift, as most people know it, is the skipping stone theory, which states that air hitting the underside of the wings push the wings up, which is true; however, this theory discounts any effect of airflow on the top and the amount of lift generation through this theory is negligible in comparison to circulation. Also, the high amount of drag that it would cost to simply produce lift by pushing the wing through the air with sheer thrust power would not make it practical for conventional airplanes.

A rule of thumb is: the lift produced is proportional to the angle of attack. This applies up to a certain point (stall), but all of the above applies to any airfoil that flies through the air, even if it is inverted. The standard teardrop shape of the airfoil is almost negligent in lift generation: airfoil shape merely helps reduce drag and makes lift production more efficient; however, even a teardropped airfoil will fly upside down fine with enough angle of attack.

[firepineapple]

Great presentation! 1 more subscriber for you : )

[TylerPaparella]

I liked the depiction of circulation in this video. There are several points that could be improved. The explanations are very simplistic. For example, the second explanation does not discuss how airflow is deflected. Another issue is the explanation involving the Coanda Effect. Real airflow over an airfoil cannot be represented by a jet stream, so the Coanda Effect does not actually apply.

[nikhilsalgar]

this channel video is helpful us....and this video content is very useful of you watching continue full For Sharing Your Knowledge....

[purulence]

Your videos are outstanding but please use another human voice. I'm suffocationg while watching :S

[adhithasimhanraghavan]

The mass of air that is left undisturbed above the air foil acts as a barrier to the flow of air particles below it. Since the airfoil tapers down, the upper part acts like an orifice with large mass of undisturbed air acting as barrier above and airfoil below. This causes the compressible fluid(air) to move faster as it expands through a diverging section, like a throat of venturi. But that is not the case with bottom part since the incoming and exiting air flows along a straight line, unlike top. That is why it creates a pressure difference between the two surfaces, due to difference is velocity of flow. Energy of a fluid is the sum of the potential, kinetic and static heads. So increase kinetic head i.e., velocity, cause drop in pressure at the top part of airfoil and produces virtually zero pressure drop bottom. That's why the life is generated.

[olivt]

The Coanda Effect does not naturally occur on a wing but it can be artificially generated using Circulation Control methods such as Jet Blowing. As a result, the Coanda Effect can increase lift dramatically, but cannot be attributed to the initial generation of lift.

[ajkorras]

pretty amazing that there is no single widely accepted answer to this question. i can imagine how many test wings have been made before working ones were found :P

[zyntekR]

Aerospace engineering student here, my professor said the air flow on top is not faster than it is on the bottom. This video is wrong

[david_porthouse]

Explanations based on Bernoulli or Newton will flop for a hydrofoil dragged slowly through liquid helium. Stick with the explanation based on the starting vortex. Our atmosphere is not a superfluid and the flow fails to double back round the trailing edge as a consequence.

[shazam]

Wrong. Wings fly because of the angle of attack, aka incidence, which compresses the air under the wing, which provides lift according to Newtons Law. The "circulating" air is non-existent nonsense.

[Absooh]

I've read on mutiple places that the "Equal-transit time" theory is false.

[pfxx]

So, by those theories a plane shouldn't be able to fly upside down?

[mouadlaloui]

Stop lying the first one create a glider is "Abess ibn Fernass " and he was arabian
;)