On the bumblebees, there's a whole deeper layer to the story. An earlier paper on insect aerodynamics was making some mistakes that were fixed in later papers by Ellington at Cambridge, a different insect researcher. (The earlier papers predicted too-small lifting forces. Until the update was made, experts truly couldn't explain bumblebee's lifting-force. Their modeling was genuinely flawed. But this issue didn't apply to all insect flight, just to ?butterfly/bumblebee? need to check this part. So, SOME insect flight was long understood. But not bumblebees.) But then in the early 1990s, Ellington made a fundamental discovery, made empirically. He noticed some brand new vortex-shedding, where previous wing-flaps were interacting with later wing-flaps. The end result was to supply the remaining unexplained lifting-force, which had always been missing from our understanding. (Detailed analyses of SINGLE wing-flaps would give wrong results, incorrect vortex-shedding, and too little lift. And the multiple wing-flaps were being simplified for analysis, the fullly detailed model apparently beyond the computers of the time.) Ellington's later discovery came from building a large robotic hawk-moth wing, and then tracking the fluid motions in a flow-chamber. (Film-camera bubble tracks. No supercomputer-arrays needed!) The new vortex was discovered in the mid-1990s, unsuspected by everyone up until that point. In other words, before the 1980s, scientists truly couldn't explain the lifting-forces produced by flapping insect wings. And then in the 1990s, the final shoe dropped. The calculated forces had always been significantly less than that required to lift the insect weight. But for decades, physicists were claiming that the "Impossible bumblebee" was only a silly myth, and being spread by ignorant people. They were wrong. The true myth was being spread by those same experts, the ones who insisted that bumblebee flight was totally explained! - www.thefreelibrary.com/Robotic+moth+reveals+key+to+insect+flight.-a019006767 How can it be that supposedly the bumblebees are fully explained, and the myth is wrong, but then in 1996 suddenly we hear that "...in effect, they've shown us how insects can fly," says biologist R. McNeill Alexander of the University of Leeds in England. He notes that (theoretical) studies had sliced the wing into two-dimensional sections and summed the lift from each part, ignoring airflow along the wing. Though they see few immediate applications, entomologists are pleased by the findings. "We've been waiting 20 years for this," says Alexander.
Well, yea. But..... In my experience, trying to explain lift via circulation falls pretty flat when you are dealing with non-technical pilots. In any case, thank you for the comment.
Great video, really enjoyed. I have a question: if the elevator (which is like a flap at the back of the airplane) is used for the plane nose to go up if it's up (used for take off), and for the plane nose to go down if the elevator is downwards (used for landing), why doesn't the same thing happen (plane nose going down) when the flaps at the wings are down?
The aircraft rotates around the center of gravity which is typically somewhere near 1/4ish of the way into the wing (from the front). The elevator has a lot of "leverage" to make the airplane pitch up or down. The flap has a less leverage - typically there are some pitch changes when you lower the flaps - but not nearly as strong. And, for landing, typically, as you get close, you hold the nose up as the airplane slows down to increase the angle of attack (angle of the wing relative to the air flow) to maintain lift.
I respectfully disagree with respects to engineers know what lift is just because they have some good equations and engineer great planes. Ptolemy had some good equations for predicting the motion of the planets but was wrong. While not quite the same, it is true either way, the success of an equation is proof of usefulness, not truthfulness. BTW, I am not a mathematician, but, I do consider myself a natural philosopher and tend to look at things a bit differently. First off there is no lift without a pressurized elastic medium whether it be gas or liquid. That means there is energy stored in the medium. Consider pressurized air battery systems. There is a 300,000 volt electrostatic potential between the ionosphere and earth at 100v/m. Comparing the relationship between the ionosphere and earth as being like a capacitor is not far off the mark considering the majority of the atmosphere is dielectric. Furthermore, we see this dielectric medium experience both discharge as arc plasma(lightning) and glow mode (Aurora), it is also known to have a dark mode invisible to the naked eye. All this information was unknown to both Newton and Bernoulli who were limited to physical properties. While watching a video recently explaining the physics behind this debate, it seemed to me there is an analogous nature in the terminology to electricity, particularly that of the electric philosophers of the 19thc. They would refer to voltage as pressure. Then it seemed the friction forces due to laminar flow over the wing is a current, so analogously its amperage. At the front of the foil there is a "pinch" effect, and visually I immediately thought of a Bennet Z pinch in a plasma. Lines drawn around a foil representing air flow/current, reminded me of magnetic field lines, imaginary lines as representations of density. If I put this all together, and pretend those lines of current are actually individual current flow, then the pinch causes these current flows to get closer as they increase in amperage, thus increasing in voltage thus experiencing an attractive force between the surface of the wing and the air mass above it, like two wires with current flowing in the same direction. The current under the foil has less amperage experiences less voltage/less pressure. Due to Relativity, is the wing moving through the air or is the air moving over the wing? Once you put motion on a foil and create air flow over the wing, within my analogy you are creating an electromagnetic field. Now can anyone tell me what the gravitational constant represents? Cheers
No, we do know how planes fly. And, it's not hard to understand the basic concepts behind how wings generate lift. ua-cam.com/video/IK2BS8BRXyU/v-deo.html Or if you prefer something from a real expert ua-cam.com/video/aa2kBZAoXg0/v-deo.html
Love your video. I can add one more myth: 11: "Lift is caused by flow curvature" youTube video search "Magnar Nordal Bernoulli" But I have to disagree with your Myth 10. That's not a myth. It's a fact. You indicate that the truth lies within Navier Stokes, Vortex Shedding etc., but there is a simple mystery: What is the cause of the pressure difference that applies the lift force on a wing? It has to be explainable in classical physics that is intelligible to a senior school physics student or at least mathematical physics graduate like myself. Shrouding the answer behind a wall of obscure and insoluble partial differential equations just doesn't do it for me. The development of wings for powered and unpowered flight has been a continuous process of trial and error for over a hundred years. Some changes improved the efficiency, some didn't. They took the useful changes and tried further variations.That's not science, that's good old engineering. Find me a scientist that can demonstrate he/she understand it. I have a theory, based on the classical physics of Boyle's Law and Charle's Law and does not rely on Bernoulli, but it's not fully developed and I'm brutally aware that I'm the "soldier who's out of step", so am keeping a low profile for the moment. But let me say that I'm deeply disturbed by the widely held statement that air over an aerofoil acts like an incompressible fluid. Air is quite patently compressible!!
@@Observ45er Sure am. Interesting Q's. re: Flow Curvature caused by pressure gradients: I'm not sure what you mean by flow curvature. No, temperature is not really significant. The real problem with the application of Bernoulli to explain the pressure variations is not so much the compressibility of air, but the lack of a) a cause of, or b) evidence of any flow acceleration over the top of the wing. It's flow acceleration that gives rise to the pressure change. And yes, indeed, I am aware of the pressure differences. Of course I am. They are, after all, the source of the aerodynamic force: a gas can only exert a force on an object via pressure (and a tiny, ignorable bit of shear stress) . But that pressure change is not caused by a change in flow velocity. You can create a pressure change in plenty of other ways.
@@Observ45er Yup, you're nearly there.: 1. "Moving wing must push air out of the way and atmospheric pressure pushes it back in behind it." and 2. "Surface moving away from air, or air moving away from surface reduces pressure." It isn't the SPEED of the air being pushed (1) or pulled (2). it's just the "push" that causes the high pressure and the "pull" that causes the low pressure. Nothing to do with Bernoulli. Nothing to do with momentum change.
@@Observ45er Now I'm confused. I have agreed with you. You said the wing pushes the air. And that the wing moving away reduces pressure. You are correct. Pushing air causes high pressure - that's what a bicycle pump does - it pushes air and creates high pressure. I don't understand what any of that has to do with Bernoulli. This isn't comedy or a joke. I don't understand why you seem to be getting annoyed with me.
Myth 1, airfoils have to be curved on top, and flat on the bottom. Not really but air and water can take higher compressions than they can take suctions before the fluid particles separate, and cavitate or boil the moisture. So when one uses low velocities where air or water particles can take the linear acceleration along a straight line or the angular acceleration on a tight curve,, one might as well curve the wing to get a better acceleration flight path field over and under the wing. . But at higher velocities where the fluid particles existing in a matrix can separate, it is foolish to use curves, and straight lines are much better. Myth 2. particles over and under the wing must meet at the trailing edge. It is so naive to talk about velocities around a wing as it is the RATE OF CHANGE OF VELOCITY hence, the acceleration field, that contributes to lifting. One can shoot a cannonball to reach the same range by inclining the gun at different angles and changing the charge. That action is basically the leading edge down angle of the slats or upper leading-edge down angle. I would say that you can use, slower, equal, and faster velocities on top of the wing and you still can get lift. Myth 3. Newton's law does not explain the low pressure on top of the wing. A fast car approaching a hill will compress its suspension system due to its mass trying to proceed in a straight line, and as it accelerates up, basically its horizontal velocity will remain constant and the fuel in the engine was used to accelerate the car vertically up, in addition to keeping its horizontal component, So at the brow of the hill, it is the gained vertical velocity that will cause the car to separate from the road and fly for some time after the brow of the hill. If behind the hill, the road slants down at the right rate of change, then the flight of the car over the road will be longer. Now add some sealing viscosity between the matrix of fluid representing many cars going over the first stages of a hill and you have the pressure suction zone at the leading edge and the suction zone all the way to the bottom of the hill. That is the upper surface of a wing. Newtonian processes are fully included in Bernoulian philosophies and all one needs is to understand their contents, which are a variation of words and symbolic language describing the same theme. Myth 4. Newton versus Bernoulli game is always a draw Myth 5. Bernoulli explains the low pressure on top of the wing. Forget the higher or lower velocity vectors as the contents of Constant = P + (V^2)^2 means that we need to square the magnitude of the velocity and so that Constant and P are a scalar and not a vector, and so even with a horizontal increase in velocity, the Pressure, WHICH IS A SCALAR, does offer its services in all directions, where P exists, and so, a change of horizontal speed can, in fact, produce a scalar pressure change which in turn can produce a vertical acceleration. In our case, we also have a change in vertical velocity, hence a vertical deceleration or acceleration which can result in low pressure, if used intelligently. Refer to a fast car navigating the hill. Myth 6. Blowing over a sheet. Since in reality, a fluid particle is complexly connected ( viscosity sealed and can shear) to an adjacent particle then the C= P + (V^2)/2 must be modified to C2= P2 + (V2^2)/2 + ( external energy gained or lost by particles moving close to compression or suction, magnetic zones) This means that when he gave energy from his lungs/mouth to the particles, these came in the vicinity of the stationary particles over the paper and they cause them to react to their higher velocity. A difference of pressure along a Streamline is the same as a difference of pressure with an adjacent streamline so the particles on different streamlines can affect one another and I call that Bernoulli effect. That is why the streamlines around the wing in a wind tunnel operate as a team as they are connected, like stacked membranes and threaded particles on a streamline, will not cross over to another but it will affect it, as it is connected to it, and not isolated form it. Myth 7. Air bouncing on the surfaces of the wing. Air particles are connected in a queue like peals in a necklace and they have got complexly connected soft cushions and pillows around them which can take compression but only a little tension. Air particles do not produce any SUDDEN IMPULSES on the wing surface and they land softly on cushions and slide along as connected pearls in a necklace or to be closer, as distributed soft cushioned masses on a sealed membrane. We can exchange pearls for children who use pillows to soften the landings on, and the slidings along wing surfaces or slides as children do! Myth 8. Pressure alone does not explain lift. Well, pressure is a scalar and acts in all directions so so it is through ingenuity that an engineer changes the scalar pressure to a vector directional force........ so I guess pressure alone does not create lift and I shall not tell you what is that additional component to use to change a scalar pressure into a FORCE VECTOR having magnitude and direction! Myth 9. Wing works like a venturi. The bounded sides of a wind tunnel set the shape of the most distant streamlines but a free-flying wing is boundless and so a venturi does not represent a wing. and the squeezing of air as it flows over an obstruction is not exactly correct, as the mass particle is like a heavy car on the level ground approaching a hill and it compresses its suspension system to later shoot it up above the brow of the hill and that is not squeezing the air. See Myth 3. Myth 10. Scientists do not understand what causes lift. It is said that mathematicians deal in unknows quantities as in ALGEBRA using symbols as X AND Y and they subject them to known operations as + - multiply and divisions and other operations, and combinations and while they deal in unknown quantities with the known operation, one has to accept that though at first, they do not know the unknowns, they certainly know what they are doing, and they do obtain accurately and guaranteed repeated results. To get an appreciation of what an engineer knows, try and follow a lump of air going through in between a pair of blades. tiny wings, of all the stages in a jet engine, starting from the compressor their stators, the diffusers, the slowing down of air to sustain the flame, the hot stator, and the final turbine with the afterburner at the end. All a jet engine is, a number of ramjets working in parallel, mounted on the circumference of a disc for the sole purpose of getting them up to high speed when the whole machine is stationary relative to the ground. That requires 500,000 years of natural human evolution and selections of the human brains and a long sifting of minds to be able to handle the invisible functions on wings.
Myth 7 is not a myth at all. The astronauts in Columbia Space Shuttle would tell you that air molecules most certainly do impact wings, and can rip them apart at high velocity. Likewise, the pilots of EgyptAir 990. Their Boeing 757 was ripped apart because the jet plunged from a high altitude toward the earth and the force of the air molecules hitting the wings at progressively higher velocities tore the wings off. Air vs. Aluminum, and the air won. Facts, like air molecules, are stubborn things.
@@crimony3054 Of course you are correct in that when the speed is very high as approaching the speed of sound, then the air molecules do impact the wings. But then the material has to be changed, as aluminum is too soft and they have to go to titanium or shape it like the Concorde. What I referred to was a well-engineered wing, made of the material suitable for a particular speed. and where the aircraft stays within the boundary limits of its design. At the moment I am thinking of the limitation of human flesh when a pilot ejects from a high-speed jet aircraft................those air molecules do tear his facial features apart. but not at the slower speeds with which a human face is supposed to operate.
On the bumblebees, there's a whole deeper layer to the story.
An earlier paper on insect aerodynamics was making some mistakes that were fixed in later papers by Ellington at Cambridge, a different insect researcher. (The earlier papers predicted too-small lifting forces. Until the update was made, experts truly couldn't explain bumblebee's lifting-force. Their modeling was genuinely flawed. But this issue didn't apply to all insect flight, just to ?butterfly/bumblebee? need to check this part. So, SOME insect flight was long understood. But not bumblebees.)
But then in the early 1990s, Ellington made a fundamental discovery, made empirically. He noticed some brand new vortex-shedding, where previous wing-flaps were interacting with later wing-flaps. The end result was to supply the remaining unexplained lifting-force, which had always been missing from our understanding. (Detailed analyses of SINGLE wing-flaps would give wrong results, incorrect vortex-shedding, and too little lift. And the multiple wing-flaps were being simplified for analysis, the fullly detailed model apparently beyond the computers of the time.)
Ellington's later discovery came from building a large robotic hawk-moth wing, and then tracking the fluid motions in a flow-chamber. (Film-camera bubble tracks. No supercomputer-arrays needed!) The new vortex was discovered in the mid-1990s, unsuspected by everyone up until that point.
In other words, before the 1980s, scientists truly couldn't explain the lifting-forces produced by flapping insect wings. And then in the 1990s, the final shoe dropped. The calculated forces had always been significantly less than that required to lift the insect weight.
But for decades, physicists were claiming that the "Impossible bumblebee" was only a silly myth, and being spread by ignorant people. They were wrong. The true myth was being spread by those same experts, the ones who insisted that bumblebee flight was totally explained!
- www.thefreelibrary.com/Robotic+moth+reveals+key+to+insect+flight.-a019006767
How can it be that supposedly the bumblebees are fully explained, and the myth is wrong, but then in 1996 suddenly we hear that "...in effect, they've shown us how insects can fly," says biologist R. McNeill Alexander of the University of Leeds in England. He notes that (theoretical) studies had sliced the wing into two-dimensional sections and summed the lift from each part, ignoring airflow along the wing. Though they see few immediate applications, entomologists are pleased by the findings. "We've been waiting 20 years for this," says Alexander.
Interesting! Thank you.
I loved the enthusiasm oozing out of this video, thank you! :)
Glad you enjoyed it!
Hell yeah. Greetings from turboprop performance engineer!
One liner: The aerofoil has a bound circulation after dumping a starting vortex in the flow, which generates lift by the Magnus effect.
Well, yea. But.....
In my experience, trying to explain lift via circulation falls pretty flat when you are dealing with non-technical pilots.
In any case, thank you for the comment.
@@LightAndSportyGuy It falls flat from a physics standpoint, as well. It's a mathematical tool to simplify calculations for the complex flow.
Great video, really enjoyed. I have a question: if the elevator (which is like a flap at the back of the airplane) is used for the plane nose to go up if it's up (used for take off), and for the plane nose to go down if the elevator is downwards (used for landing), why doesn't the same thing happen (plane nose going down) when the flaps at the wings are down?
The aircraft rotates around the center of gravity which is typically somewhere near 1/4ish of the way into the wing (from the front). The elevator has a lot of "leverage" to make the airplane pitch up or down. The flap has a less leverage - typically there are some pitch changes when you lower the flaps - but not nearly as strong.
And, for landing, typically, as you get close, you hold the nose up as the airplane slows down to increase the angle of attack (angle of the wing relative to the air flow) to maintain lift.
@@LightAndSportyGuy I see now, thank you for clarifying!
Vielen Dank Udachi !!
I respectfully disagree with respects to engineers know what lift is just because they have some good equations and engineer great planes. Ptolemy had some good equations for predicting the motion of the planets but was wrong. While not quite the same, it is true either way, the success of an equation is proof of usefulness, not truthfulness. BTW, I am not a mathematician, but, I do consider myself a natural philosopher and tend to look at things a bit differently.
First off there is no lift without a pressurized elastic medium whether it be gas or liquid. That means there is energy stored in the medium. Consider pressurized air battery systems. There is a 300,000 volt electrostatic potential between the ionosphere and earth at 100v/m. Comparing the relationship between the ionosphere and earth as being like a capacitor is not far off the mark considering the majority of the atmosphere is dielectric. Furthermore, we see this dielectric medium experience both discharge as arc plasma(lightning) and glow mode (Aurora), it is also known to have a dark mode invisible to the naked eye. All this information was unknown to both Newton and Bernoulli who were limited to physical properties.
While watching a video recently explaining the physics behind this debate, it seemed to me there is an analogous nature in the terminology to electricity, particularly that of the electric philosophers of the 19thc. They would refer to voltage as pressure. Then it seemed the friction forces due to laminar flow over the wing is a current, so analogously its amperage. At the front of the foil there is a "pinch" effect, and visually I immediately thought of a Bennet Z pinch in a plasma. Lines drawn around a foil representing air flow/current, reminded me of magnetic field lines, imaginary lines as representations of density. If I put this all together, and pretend those lines of current are actually individual current flow, then the pinch causes these current flows to get closer as they increase in amperage, thus increasing in voltage thus experiencing an attractive force between the surface of the wing and the air mass above it, like two wires with current flowing in the same direction. The current under the foil has less amperage experiences less voltage/less pressure. Due to Relativity, is the wing moving through the air or is the air moving over the wing? Once you put motion on a foil and create air flow over the wing, within my analogy you are creating an electromagnetic field.
Now can anyone tell me what the gravitational constant represents?
Cheers
So a wing is basically an antigravity device… this explains flying saucers… !
So.
Nobody knows why a plane flies, but they fly.
No, we do know how planes fly. And, it's not hard to understand the basic concepts behind how wings generate lift. ua-cam.com/video/IK2BS8BRXyU/v-deo.html Or if you prefer something from a real expert ua-cam.com/video/aa2kBZAoXg0/v-deo.html
You may find this helpful drive.google.com/file/d/1DmMKH77keUBt0kWoSWQYfSMXelAJhzlG/view?usp=sharing
FWD Momentum redirected downward =‘s lift
Love your video. I can add one more myth:
11: "Lift is caused by flow curvature" youTube video search "Magnar Nordal Bernoulli"
But I have to disagree with your Myth 10. That's not a myth. It's a fact.
You indicate that the truth lies within Navier Stokes, Vortex Shedding etc., but there is a simple mystery:
What is the cause of the pressure difference that applies the lift force on a wing?
It has to be explainable in classical physics that is intelligible to a senior school physics student or at least mathematical physics graduate like myself. Shrouding the answer behind a wall of obscure and insoluble partial differential equations just doesn't do it for me.
The development of wings for powered and unpowered flight has been a continuous process of trial and error for over a hundred years. Some changes improved the efficiency, some didn't. They took the useful changes and tried further variations.That's not science, that's good old engineering.
Find me a scientist that can demonstrate he/she understand it.
I have a theory, based on the classical physics of Boyle's Law and Charle's Law and does not rely on Bernoulli, but it's not fully developed and I'm brutally aware that I'm the "soldier who's out of step", so am keeping a low profile for the moment. But let me say that I'm deeply disturbed by the widely held statement that air over an aerofoil acts like an incompressible fluid. Air is quite patently compressible!!
@@Observ45er Sure am. Interesting Q's. re: Flow Curvature caused by pressure gradients: I'm not sure what you mean by flow curvature.
No, temperature is not really significant. The real problem with the application of Bernoulli to explain the pressure variations is not so much the compressibility of air, but the lack of a) a cause of, or b) evidence of any flow acceleration over the top of the wing. It's flow acceleration that gives rise to the pressure change.
And yes, indeed, I am aware of the pressure differences. Of course I am. They are, after all, the source of the aerodynamic force: a gas can only exert a force on an object via pressure (and a tiny, ignorable bit of shear stress) . But that pressure change is not caused by a change in flow velocity. You can create a pressure change in plenty of other ways.
@@Observ45erWhen the plane is flying through still air, where's the fluid flow?
@@Observ45er Yup, you're nearly there.:
1. "Moving wing must push air out of the way and atmospheric pressure pushes it back in behind it."
and
2. "Surface moving away from air, or air moving away from surface reduces pressure."
It isn't the SPEED of the air being pushed (1) or pulled (2). it's just the "push" that causes the high pressure and the "pull" that causes the low pressure.
Nothing to do with Bernoulli. Nothing to do with momentum change.
@@Observ45er Nope, I have known this for a long time. I'm just getting better at explaining it.
@@Observ45er Now I'm confused. I have agreed with you. You said the wing pushes the air. And that the wing moving away reduces pressure. You are correct.
Pushing air causes high pressure - that's what a bicycle pump does - it pushes air and creates high pressure.
I don't understand what any of that has to do with Bernoulli.
This isn't comedy or a joke. I don't understand why you seem to be getting annoyed with me.
OMG
?
Myth 1, airfoils have to be curved on top, and flat on the bottom. Not really but air and water can take higher compressions than they can take suctions before the fluid particles separate, and cavitate or boil the moisture. So when one uses low velocities where air or water particles can take the linear acceleration along a straight line or the angular acceleration on a tight curve,, one might as well curve the wing to get a better acceleration flight path field over and under the wing. . But at higher velocities where the fluid particles existing in a matrix can separate, it is foolish to use curves, and straight lines are much better.
Myth 2. particles over and under the wing must meet at the trailing edge. It is so naive to talk about velocities around a wing as it is the RATE OF CHANGE OF VELOCITY hence, the acceleration field, that contributes to lifting. One can shoot a cannonball to reach the same range by inclining the gun at different angles and changing the charge. That action is basically the leading edge down angle of the slats or upper leading-edge down angle. I would say that you can use, slower, equal, and faster velocities on top of the wing and you still can get lift.
Myth 3. Newton's law does not explain the low pressure on top of the wing. A fast car approaching a hill will compress its suspension system due to its mass trying to proceed in a straight line, and as it accelerates up, basically its horizontal velocity will remain constant and the fuel in the engine was used to accelerate the car vertically up, in addition to keeping its horizontal component, So at the brow of the hill, it is the gained vertical velocity that will cause the car to separate from the road and fly for some time after the brow of the hill. If behind the hill, the road slants down at the right rate of change, then the flight of the car over the road will be longer. Now add some sealing viscosity between the matrix of fluid representing many cars going over the first stages of a hill and you have the pressure suction zone at the leading edge and the suction zone all the way to the bottom of the hill. That is the upper surface of a wing. Newtonian processes are fully included in Bernoulian philosophies and all one needs is to understand their contents, which are a variation of words and symbolic language describing the same theme.
Myth 4. Newton versus Bernoulli game is always a draw
Myth 5. Bernoulli explains the low pressure on top of the wing. Forget the higher or lower velocity vectors as the contents of
Constant = P + (V^2)^2 means that we need to square the magnitude of the velocity and so that Constant and P are a scalar and not a vector, and so even with a horizontal increase in velocity, the Pressure, WHICH IS A SCALAR, does offer its services in all directions, where P exists, and so, a change of horizontal speed can, in fact, produce a scalar pressure change which in turn can produce a vertical acceleration. In our case, we also have a change in vertical velocity, hence a vertical deceleration or acceleration which can result in low pressure, if used intelligently. Refer to a fast car navigating the hill.
Myth 6. Blowing over a sheet. Since in reality, a fluid particle is complexly connected ( viscosity sealed and can shear) to an adjacent particle then the C= P + (V^2)/2 must be modified to C2= P2 + (V2^2)/2 + ( external energy gained or lost by particles moving close to compression or suction, magnetic zones) This means that when he gave energy from his lungs/mouth to the particles, these came in the vicinity of the stationary particles over the paper and they cause them to react to their higher velocity. A difference of pressure along a Streamline is the same as a difference of pressure with an adjacent streamline so the particles on different streamlines can affect one another and I call that Bernoulli effect. That is why the streamlines around the wing in a wind tunnel operate as a team as they are connected, like stacked membranes and threaded particles on a streamline, will not cross over to another but it will affect it, as it is connected to it, and not isolated form it.
Myth 7. Air bouncing on the surfaces of the wing. Air particles are connected in a queue like peals in a necklace and they have got complexly connected soft cushions and pillows around them which can take compression but only a little tension. Air particles do not produce any SUDDEN IMPULSES on the wing surface and they land softly on cushions and slide along as connected pearls in a necklace or to be closer, as distributed soft cushioned masses on a sealed membrane. We can exchange pearls for children who use pillows to soften the landings on, and the slidings along wing surfaces or slides as children do!
Myth 8. Pressure alone does not explain lift. Well, pressure is a scalar and acts in all directions so so it is through ingenuity that an engineer changes the scalar pressure to a vector directional force........ so I guess pressure alone does not create lift and I shall not tell you what is that additional component to use to change a scalar pressure into a FORCE VECTOR having magnitude and direction!
Myth 9. Wing works like a venturi. The bounded sides of a wind tunnel set the shape of the most distant streamlines but a free-flying wing is boundless and so a venturi does not represent a wing. and the squeezing of air as it flows over an obstruction is not exactly correct, as the mass particle is like a heavy car on the level ground approaching a hill and it compresses its suspension system to later shoot it up above the brow of the hill and that is not squeezing the air. See Myth 3.
Myth 10. Scientists do not understand what causes lift. It is said that mathematicians deal in unknows quantities as in ALGEBRA using symbols as X AND Y and they subject them to known operations as + - multiply and divisions and other operations, and combinations and while they deal in unknown quantities with the known operation, one has to accept that though at first, they do not know the unknowns, they certainly know what they are doing, and they do obtain accurately and guaranteed repeated results. To get an appreciation of what an engineer knows, try and follow a lump of air going through in between a pair of blades. tiny wings, of all the stages in a jet engine, starting from the compressor their stators, the diffusers, the slowing down of air to sustain the flame, the hot stator, and the final turbine with the afterburner at the end. All a jet engine is, a number of ramjets working in parallel, mounted on the circumference of a disc for the sole purpose of getting them up to high speed when the whole machine is stationary relative to the ground. That requires 500,000 years of natural human evolution and selections of the human brains and a long sifting of minds to be able to handle the invisible functions on wings.
Myth 7 is not a myth at all. The astronauts in Columbia Space Shuttle would tell you that air molecules most certainly do impact wings, and can rip them apart at high velocity. Likewise, the pilots of EgyptAir 990. Their Boeing 757 was ripped apart because the jet plunged from a high altitude toward the earth and the force of the air molecules hitting the wings at progressively higher velocities tore the wings off. Air vs. Aluminum, and the air won. Facts, like air molecules, are stubborn things.
@@crimony3054 Of course you are correct in that when the speed is very high as approaching the speed of sound, then the air molecules do impact the wings. But then the material has to be changed, as aluminum is too soft and they have to go to titanium or shape it like the Concorde. What I referred to was a well-engineered wing, made of the material suitable for a particular speed. and where the aircraft stays within the boundary limits of its design. At the moment I am thinking of the limitation of human flesh when a pilot ejects from a high-speed jet aircraft................those air molecules do tear his facial features apart. but not at the slower speeds with which a human face is supposed to operate.