Wing lift Holger Babinsky

[tomterahedrob]

Ahh 40 years later and I thought so!Thanks!

[PaulDowsettUK]

It would be interesting to see the same experiment with a perfectly flat wing at the same AoA.

[connorkokora]

I was really anticipating another paragraph of narration.

[kenlew]

Thank you Dr. Babinsky for a brilliant explanation of how streamlines influence pressure changes resulting in lift on airfoils. This helped explained my research on standard vs KF airfoils which gained first place at a local science fair...Currently, in year 9 and hopeful Cambridge candidate in the future!

[seaman]

i always said that the wing generates lift because it trows air down at the end ; the rounded surface at the top is only there to prevent airflow separation as it changes direction gradually

[YashRaj-yupi]

didn't understand whether viscosity of air was taken into consideration in above demonstration as it seems different streams of air with smoke touches the wing.

[fatcharlieuk]

I'd like to see the video at a less extreme angle of attack. An aircraft flying (or _trying_ to fly) at this high AOA would certainly be at the incipient stall stage. Maybew the buffeting we feel pre-stall is something to do with the differing arrival times at the trailing edge? show me a wing at a normal angle of attack and I'd be more convinced.

[TheTruthKiwi]

So does this mean that the moving air is pushing the wing up afterall?

[rolandtamaccio]

The end of the upper surface of the wing, or the end of the effective area, as seen by the flow separation , ,, ?

[josephinebennington]

Still not a simple sentence. Can we say that the aerofoil is A) sucked in a direction by reduced air pressure over the long curve, or pushed in a direction by the cushion it creates as its AoA simply must push air down? And....whether against or with gravity (up or down) is dependent on the tail plane doing a separate job?

[PaulDowsettUK]

It would be useful to see the same streams unobstructed (without the aerofoil), to act as a control, to demonstrate whether the actual speed of the airstreams over and under the aerofoil increases and decreases respectively, or if it's simply relative to each other.

[reyanshshetty]

I had a question, why does it matter if the molecules reach the end of the airfoil at the same time, if the molecules at the top surface reach earlier, it would mean that they are faster and there by the lift force would be generated via bernoulli's principle.

[johnciber]

Motion (sails)/lift (wings) is mainly due to wind deflection to the stern (sails) / to down (wings).
shows that close-hauled motion is possible with NO wind on leeward side (thus no effect on that side).

[vlatkopopovski]

The authors have two wrong scientific approaches: researching the creation of Lift force and Low pressure at upper side of the wing, relative to the ground surface and Earth. I explain the aerodynamic cavitation and existence of Lee side aerocavern, and creation of Aerodynamic force.

[RationalDiscourse]

0:42 I don't see that it "speeds up as it approaches the airfoil". If anything, it appears to lag behind the smoke in the undisturbed airflow at the top of the screen. If the air doesn't accelerate over the top of the wing, how can it generate the well established low pressure which generates the lift from the top surface?

[bagnon]

This demo doesn't create vacuum like a plane would.

[terrywayneHamilton]

What is important ; visualize the smoke and it does not deflect down. A propeller, a rotor blade, a fan all move air at 90 degrees from travel of blade this is a known event and supports Newton law of force ; however, the pressure difference is also measured as a dynamic event and thus can not be discounted . Air is sticky when in laminar format and a wing is always in line with flight vector of the incidents of cord of wing. This would support pressure difference of top to bottom of wing as primary event in lift with Newton Law of Reaction as a measurement of the pressure. Like gravity, it is not behaving as anticipated, , , , .

[david_porthouse]

If you do this experiment in liquid helium, you will see that the equal transit time theory is correct. You will also see that there is no net lift.

Repeat the experiment in liquid sodium. You will find that equal transit time theory is wrong, and net lift is produced. The moving hydrofoil produces a relative displacement of the fluid above and below it. If you follow this back to the place where the hydrofoil started, then you will find a starting vortex whose presence avoids an apparent issue with the conservation of mass.

There is no such starting vortex in liquid helium, which is how I know that equal transit time will be correct.

[alans]

Is it possible that Prof. Babinsky has also debunked the Bernoulli argument as well? The argument that the low pressure above the wing is generated by the increased airspeed over the wing. From the frames at 0:42 onwards, it is quite clear that the air flowing over the upper surface of the wing has not speeded up. In all those frames, the wind over the top surface of the wing is moving at the same speed as the ambient air at the top and bottom of the screen.
Is this a show stopper?