How wings work?

[ZeeOSix]

You obviously did not read what I said. YOU FIRST PRESSURIZE IT THEN RELEASE THE PRESSURE THEN YOU HAVE THE FOG AS THE AIR PRESSURE FALLS OFF. When dense it packs the water when released it turns to gas or fog.
I could demonstrate a wing creating lift with no airflow what so ever over the top of the wing. Matter of fact I could also add some weight on top that wing with stagnate air covering the whole top of the wing. Some day when I have lots of spare time I'll build the demonstration wind tunnel to do that.
Bernoulli ? Not needed to fly. For venturi's yes.

I read your post right, and said why there was fog created in the pressurized bottle trick. Yes, fog will appear if moist air is compressed, then suddenly decompressed. But fog can also form in moist air any time the air pressure gets low enough below the normal atmospheric pressure - the air doesn't necessarily have to be compressed first.

Why do you think vapor only forms on the top side of wings, and why do wings bend upward while the plane is in the air - see attached video. When the moist air above the wing area simply lowers below the atmospheric pressure (without being compressed first), then water vapor in the air will turn to fog.

 

[y_p_w]

I was in our HS aviation club. The sponsoring teacher had a private pilot license and a commercial license where he could do stuff like transport prisoners for pay. He was big on airfoils and the pressure differential being stupid because fighter jets could fly upside down and didn't have a standard airfoil shape. But I think that's what happens when enough thrust is thrown in - that it's pressing against the bottom.

However, I created one of those hand launched propellers once in wood shop class in jr high. I created mine with a flat and level bottle with a basic airflow shape. The one on the top here:

It lifted just fine. I've seen some for sale and they're just flat with an angle of attack, and they work too, but just a different way.

 

[ZeeOSix]

The Measurement of the Pressure Distribution over the Wing of an Aircraft in Flight

http://unsworks.unsw.edu.au/fapi/datastream/unsworks:3570/SOURCE01

 

[Exhaustgases]

I read your post right, and said why there was fog created in the pressurized bottle trick. Yes, fog will appear if moist air is compressed, then suddenly decompressed. But fog can also form in moist air any time the air pressure gets low enough below the normal atmospheric pressure - the air doesn't necessarily have to be compressed first.

Why do you think vapor only forms on the top side of wings, and why do wings bend upward while the plane is in the air - see attached video. When the moist air above the wing area simply lowers below the atmospheric pressure (without being compressed first), then water vapor in the air will turn to fog.

Very cool. If you study it enough, you can see the vapor is coming out the rear of the wing and the plane is sinking, the compression is at the bottom of the wing and at the rear of the wing the compressed air is released and the vapor forms. It is a misleading photo.

 

[ZeeOSix]

^^^ Read the paper linked in Post #43. Wings make lift because the pressure on the top surface is less than on the bottom surface. What else makes wings bend upward in flight and keep an airplane in the air. The vapor clouds in that video are only on the top surface of the wing where the pressure is much lower than on the bottom side.

 

[Exhaustgases]

There is a huge minus pressure at the last point of landing from the shadow effect from the lower wing. Air speed is too low to create your precious Bernoulli lift. The pressure at the top of the wing is not needed for lift, it could be static and the wing would still fly. I can prove it.
Even a simple rock skipping on water is a simple sort of analogy.

 

[ZeeOSix]

There is a huge minus pressure at the last point of landing from the shadow effect from the lower wing. Air speed is too low to create your precious Bernoulli lift. The pressure at the top of the wing is not needed for lift, it could be static and the wing would still fly. I can prove it.
Even a simple rock skipping on water is a simple sort of analogy.

My point is, regardless of exactly how air flows over a wing surface or the exact pressure distribution, it's a fact that the pressure distribution on the upper surface is less than the pressure distribution on the bottom surface, and that's what causes the overall upward lift forces on the wing. The paper I linked proves it with measured pressure distribution data with a real airplane in flight, then comparing that data to wing models doing the same. In your skipping stone example, the rock "floats/flys" across the water because the pressure on the bottom surface is still higher than on the top surface ... same thing required on a wing in order to give it lift.

 

[BusyLittleShop]

Aerodynamically speaking the Mustang sported a wing that no other
fighter either friend of foe used... the Mustang's laminar flow wing
was a success and its performance in the air war is now legendary...
In cross section the wing is slightly thicker than its rivals but the
maximum thickness is further back from the leading edge, being near
the center of the cord, and the bottom trailing edge is a modified
cusp... The shape of this NACA 66 series air foil permitted the
transition from laminar to turbulence flow to be generated further and
thus reduce the profile drag or air resistance by a great margin than
previous air foils available in 1939 by friend or foe... 6/4 laminar

 

[Exhaustgases]

The only important pressure on the wing is what is on the bottom of it period. Laminar flow over top and bottom of the wing, that is high enough velocity may act like stabilizing medium to, for lack of better terms lock the wing between the air layers and hold it in position.
The negative pressure if any, just look at the symmetrical examples above, is not as strong as thought. Like I have said if it was the fabric of old planes would be ripped off from the so called extreme negative pressure above the wing. That is your proof of how not so negative it is. Does it help? Of course it does. But it is not the major contribution to lift like is taught everywhere. A wing will fly with no airflow over the top of it.
Very easy to prove.

 

[ZeeOSix]

Nobody is claiming the pressure on the upper wing is at like vacuum levels and ripping the fabric or skin off the wing. The fact is the pressure above the wind is less than the bottom, and the larger the delta-p between them simply increases the lifting force on the wing - that's what is actually important. If there was hardly any pressure delta between the top and bottom surfaces, the wings would have to be larger (more surface area) in order to achieve enough lift to keep the plane in the air. Nobody can prove that a wing will produce lift if the pressure field on both sides is exactly the same.

 

[RooflessVW]

I could demonstrate a wing creating lift with no airflow what so ever over the top of the wing. Matter of fact I could also add some weight on top that wing with stagnate air covering the whole top of the wing. Some day when I have lots of spare time I'll build the demonstration wind tunnel to do that.
Bernoulli ? Not needed to fly. For venturi's yes.

Honestly man, it's time to put up or shut up.

Make the demonstration, do the math, show your work.

 

[MolaKule]

The only important pressure on the wing is what is on the bottom of it period. Laminar flow over top and bottom of the wing, that is high enough velocity may act like stabilizing medium to, for lack of better terms lock the wing between the air layers and hold it in position.
The negative pressure if any, just look at the symmetrical examples above, is not as strong as thought. Like I have said if it was the fabric of old planes would be ripped off from the so called extreme negative pressure above the wing. That is your proof of how not so negative it is. Does it help? Of course it does. But it is not the major contribution to lift like is taught everywhere. A wing will fly with no airflow over the top of it.
Very easy to prove.

Hopefully this will add some aerodynamic's science to the discussion.

 

[adams355]

No one ever reads my links. Do you think NASA might have it right?

This site has moved to a new URL

 

[MolaKule]

No one ever reads my links. Do you think NASA might have it right?

I am not sure what you mean by "getting it right."

What NASA is explaining is that when modeling and simulating wing profiles. you start off with the theories of Bernoulli and Newton, then you expand to the more complex Euler and Navier-Stokes equations for conservation of mass and momentum,

Euler equations (fluid dynamics) - Wikipedia

en.wikipedia.org

Navier–Stokes equations - Wikipedia

en.wikipedia.org

and then incorporate Prandtl's theories of thermal diffusivity and momentum for high-speed flight,

Prandtl number - Wikipedia

en.wikipedia.org

Equations [1.7], [1.8], [1.11] demonstrate the principle stated earlier, namely, the sources of aerodynamic lift, drag, and moments on a body are the pressure and shear stress distributions Integrated over the body.

Bold Emphasis mine.

Reference: Anderson, J.D., Fundamentals of Aerodynamics, McGraw-Hill.

 

[wpod]

Wings work pretty good other wise planes wouldn't be able to fly.

 

[adams355]

I wasn't referring to your post @MolaKule just adding some information that I had previously put up but it was overlooked.

 

[Cujet]

Inertia is the term you guys are looking for.

Exhaust gasses makes the point that he can make a wing that has a one sided lifting surface. He's correct, and it's not hard to do. A space capsule falling to Earth is such a lifting surface. It's flat on the bottom and teardrop shaped on top. It works well at 10,000 MPH. However, it appears he is avoiding the larger picture. A low drag, high lift wing that performs well at low airspeeds is a known quantity. Impact pressure on the lower surface of a wing is only part of the equation.

To smoothly utilize the inertia of air molecules at the speeds we use to takeoff, fly and land requires a well refined design. To state otherwise is not accurate.

There is a reason this wing works so well, and there is a very distinct reason that such a small set of spoilers utterly kills the lift of that wing. The L/D is 50 to 1 in normal flight. L/D drops into the single digits with those spoilers out. The bottom of the wing is not an effective place for spoilers.

Note: I fly one of these.

 

[Exhaustgases]

The spoilers that are aft on top the wing do what a spoiler would do on a car. It forces the area below it to the ground, and is in essence a flap that pushes down or gathers more positive pressure to the top of the wing. The normal flaps (under the wing) help create more cup effect to the bottom of the wing, very similar to the cup effect of the parachute shown above. The cupped wing holds more positive pressure, and of course more air is directed down. Spoilers destroy lift by forcing the wing down just opposite from what the flaps do. And thank you Cujet your a breath of fresh air on this topic. I'd like to hear more from the well respected MolaKule also a breath of fresh air.

 

[MolaKule]

Skydiving or the use of canopy parachutes to retard decent velocity falls under the subject matters of increased drag and Archimede's principle of buoyancy forces:

Physics of Skydiving

Skydiving is a great example of many of the physics concepts that we have discussed thus far in our class. First we can examine the forces ...

colgatephys111.blogspot.com

I think what many are failing to see here is that the wing is a three-dimensional body that has a three-dimensional flow field interacting with it and it takes the three conservation principles of energy, momentum, and mass to fully explain Lift, Drag and the other forces acting upon it..

Additionally, there is a finite pressure distribution above and below the wing at each station and span position. This pressure distribution varies with wing velocity and angle of attack..

 

[Exhaustgases]

Buoyancy, exactly. Just like a boat will not have water on top of it to help it float, same with a wing not needing assist from the top area as well.
It is the velocity (forward motion) and angle of attack that builds a pressure wedge of sorts similar to a long flat bearing surface like a rock skipping on the water. The harder higher pressure air is what the wing floats on. And can easily be proven in a correctly specially designed proof on concept demonstration wind tunnel, the top of the wing can be exposed to stagnate atmospheric air pressure and the bottom of the wing is exposed to a nice 300 mph or more breeze. That wing will create lift just fine.