Airflow across a wing

"It is often said that the lift on a wing is generated because the flow moving over the top surface has a longer distance to travel and therefore needs to go faster. This common explanation is actually wrong." Here, aerodynamics expert Professor Holger Babinsky from the University of Cambridge's Department of Engineering debunks a popular, yet misleading, explanation of how wings lift.
For more information, read the accompanying story published by the University of Cambridge http://www.cam.ac.uk/research/news/ho...

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  Education

[JLCProductions]

All right, that was the wrong explanation, we all understood it's wrong.

What about the right one?

[Dmitri Shuralyov]

Lift comes from 2 things:

1. angle of attack

2. shape of wing

In this video, the angle of attack is so extreme that most of the lift comes from there.

If they used a 0 degree angle of attack, then the shape of wing and what they're visualizing would actually make sense.

[completeaerogeek]

If you look at the reference smoke lines (the ones above the wing closest to the wind tunnel wall you will see that the air does.not accelerate but rather remains constant except close to the wing surface where form drag slows it down and it changes direction causing a density change and a lifting force. The differential velocity comes from the lower surface pushing the air forwards and down. The bow wave can be seen influencing the air before it comes in contact with the wing's lower surface.

[caesareor]

Actually this is a very good example to explain why it can also fly upside-down. You can see that the wing profile is symmetrical so it makes no difference if you turn the plane upside-down. All you need is airspeed and angle of attack.

It is also possible with an asymmetrical profile but you would have some differences in efficiency

[theokpianocoverguy]

BABINSKI best lecturer ever =)

[37rainman]

The "actual force upward" is caused by air molecules (mass) colliding with the wing and causing lift due to an equal and opposite reaction. Lift is not created by something happening somewhere "beyond the trailing edge". This does not in any way serve to deny that a part of the lift is attributable to the "shaped wing" concept, explainable by bernoillis principles.

[Stealtht6]

the pressure differential is insufficient to generate lift. The actual force upward is due to the down force of the air beyond the trailing edge. That air being forced down has an opposite reaction force on the wing pushing it upward. (Think Newton)

[MikeCPeters]

The air over the top of the wing flows faster, so at a lower pressure.

The air under the wing flows slower, so at a higher pressure

So more molecules bouncing harder against the underside of the wing

Fewer molecules bouncing less hard against the top of the wing

This gives a pressure differential, with a resultant force towards the top of the wing.

This acts to counter the weight of the aircraft, so we fly.

[SaxmanNateEarthsong]

easy same way just upside down. Notice the angle of the wing turn it upside down and point the nose down and you stay up.....

[Hai Chen]

Who is the self confident yahoo that analyzed and voiced this video? Clearly does not have an understanding of aerodynamics and flow properties. I'd state all the errors in OP's deductions, but there are plenty of comments correctly correcting him already.

[burninrock24]

because the shape of the wing doesnt change when you flip it upside down. It still generates lift.