If you study the literature you will find that there is no correct theoretical explanation of flight. The explanations offered can be classified as
- trivial and correct (for uneducated)
- trivial and incorrect (for uneducated)
- nontrivial but incorrect (for educated).
What is needed is a nontrivial correct theory for both educated and uneducated and this is what we offer on this site. The trivial or incorrect theories often overlap by combinations of trivial or incorrect elements. The understanding of the beauty and usefulness of the nontrivial correct theory is facilitated by understanding what trivial or incorrect theories say. To properly appreciate what is nontrivial and correct requires knowing what is incorrect or trivial. A Google image search on “airfoil lift” gives a large collection of images all incorrect none depicting anything near the truth.
See also Secret of Flight Part IV Incorrect Theory.
NASA STATE-OF-THE-ART TRUTH
NASA presents several incorrect theories for lift listed below, but no theory claimed to be correct. NASA argues as if by discarding all incorrect theories, what remains would be the correct theory, but science does not work this way because there are infinitely many incorrect theories, and the correct theory does not come out from a negation.
NASA ends with an cryptic message connecting back to Bernouili and Newton:
- To truly understand the details of the generation of lift, one has to have a good working knowledge of the Euler Equations.
This is a cover-up of the fact that NASA does not know what keeps airplanes in the air, which of course cannot be admitted.
In pilots handbooks it is common to simply avoid the question of how lift is generated, by suggesting that it is so natural that no explanation at all is needed, as in
telling a lot about generation of drag but nothing about lift.
1. Trivial and Correct: Newton’s Third Law
Air is deflected downwards (downwash) and as a reaction there is an upward force on the airplane which is lift. This is correct but trivial, since it does not explain why air is deflected downwards. It is often used in presentations directed to people without formal training in aerodynamics:
2. Trivial and Incorrect
2.1. Longer Path Theory
Watch the incorrect longer path theory being carefully explained in
and contradicted by
2.2. Downwash Theory
2.3. Bernoulli’s Principle
A popular explanation of lift is to refer to Bernouilli’s Principle which connects high velocity to low pressure and say that because the velocity of air on top of the wing is bigger than the below, the pressure on top will be smaller than below and thus create lift, which is the message in
- Bernoulli’s Principle
- The Aerodynamics of Flight
- Physics in a minute: How wings really create lift
- How Airplanes Fly
- Forces of Flight
- Aerodynamics for Pilots 1
- Why Do Airplanes Stall?
- Theory of Flight- MIT.
But it is not explained why the velocity is higher on top, and so the explanation of lift presented is no real explanation, or more precisely a trivial truism: There is lift because the pressure on top is lower than below.
2.4. Coanda Effect
The Coanda effect is the tendency of a fluid jet to be attracted to a nearby surface as in the kitchen sink experiment with the cylinder being pulled to the left by the deviation of fluid flow which appears “to be sticking” to the cylinder surface:
A connection is made to the lift of a a wing created by the air flow above the wing being similarly deviated by “sticking to” the upper surface of the wing. What remains to be explained is why the flow “sticks to the surface” and does not separate before the trailing edge. A common misconception is expressed in How Airplanes Fly: A Physical Description of Lift, by flight experts Anderson and Eberhardt:
- Why should a fluid follow a curved surface? The answer is viscosity: the resistance to flow which also gives the air a kind of “stickiness.”
The new theory shows that this incorrect: the flow “sticks” because it is incompressible and the viscosity is so small that a slip boundary condition applies, not because the flow is viscous with a viscous boundary layer.
3. Non-Trivial but Incorrect
3.1. Kutta-Zhukosky Lift Theory
The only nontrivial theory of lift is that by Kutta-Zhukovsky presented at the time of the first powered flight in the early 20th century. Kutta and Zhukovsky found that by modifying zero lift/drag potential flow by a large scale flow circulating around the wing section, a flow with lift (but no drag) was created as illustrated in the following generic picture of the theory:
The logic was that since circulation gives lift and there is lift, there must be circulation. But this is not correct logic, because it is possible that lift is created by something else than circulation, and this turns out to be the case as shown in the new theory.
Nevertheless, Kutta-Zhukovsky circulation theory is the standard “educated” explanation of lift by e.g.
- US Centennial Flight Commission
- Physical Principles of Winged Flight
- NASA Introduction to the Aerodynamics of Flight
- The Origins of Lift
- See How It Flies
- Two-Dimensional Airfoil Theory.
Kutta-Zhukovsky theory invents lift from a mechanism which does not occur in reality: The new theory explained on this site shows that lift and drag are both generated from a basic instability mechanism of potential flow which is not Kutta-Zhukovsky’s circulation. Here you find more about Kutta-Zhukovsky:
- Kutta-Zhukosvky
- The Spell of Kutta-Zhukovsky’s Circulation Theory
- Wikipedia Coverup
- Kelvin’s Theorem Unphysical.
3.2 Lifting Line Theory
Prandtl developed (borrowing from Lancaster) an elaboration of KZ circulation theory in the form of lifting-line theory, which is also unphysical.
3.3. Prandtl Drag Theory
Kutta-Zhukovsky did not offer any explanation of drag and it was the young German physicists Ludwig Prandtl who took on this burden in Motion of Fluids with Very Little Viscosity, which made him the father of modern fluid mechanics. In this 8 page note Prandtl suggested that drag was an effect of a very thin boundary layer attaching the flow to a solid boundary, which when separating causes a wake of turbulent flow creating drag. But Prandtl does not explain lift (nor drag).
The new theory shows that Prandtl speculation has nothing to do with real physics: Drag originates from the same instability of potential flow which gives lift to a wing, and does not come from any boundary layer. Read:
The Secret of Flight 
Please look for http://www.flugtheorie.de
Hello Jan Peter: You present the standard circulation theory, which we show is non-physical and thus incorrect. Have you read and understood our arguments?
Hallo claesjohnson,
you say: „You present the standard circulation theory“
I’m shocked!
The theory of flying is simple: An airplane flies by air masses accelerating downwards.
Five words!
The recoil from it is the lift force.
All others is technology and no more physics.
Why did you not see this?
The circulation is not a cause of something, but a result. Please have a newer look in chapter
„aerodynamical physics“. in the english part of the Page.
With greetings!
Peter Apel
You present a triviality, but flight is not a triviality. Why does a fixed wing make air masses accelerate downwards giving big lift at the price of small drag? Your explanation explains nothing but the trivial fact that by Newton’s 3rd law lift is generated by pushing air down.
Read New Theory of Flight and you will understand that flight is form of miracle and not a triviality.
Hallo claesjohnson
If you study the literature you will find that there is no correct theoretical explanation of flight.
OK
The explanations offered can be classified as
trivial and incorrect (for uneducated)
nontrivial but incorrect (for educated).
OK
What is needed is a nontrivial correct theory for both educated
Sorry, no.
It is needed a trivial and correct (for uneducated and educated)
Why?
The natur ist functioning by very very very simple principles. Such like Newton´s three laws. The law for forces and for each arisings of forces is only only only the one by Newton: accelerating masses.
„There are no other forces then my ones“, says Newton, if he is alive.
Lift is a force and nothing others than a force. That says nasa very correctly.
You present a triviality, but flight is not a triviality.
Who sayd it? I know: all. But, physics is no democracy! In the whole history each new knowledges were not understood by the majority, in particular, when the new stood against what exists.
Why does a fixed wing make air masses accelerate downwards giving big lift
at the price of small drag? Your explanation explains nothing but the trivial
fact that by Newton’s 3rd law lift is generated by pushing air down.
…….the trivial fact that by Newton’s 3rd law lift is generated by pushing air down:
This is precisely the secret of flying, without anything else.
Why is it so hard to understand?
You see in my page the directly resulting formula. No other theory that can. That means something valuable, right?
My theory (I’m sure I’m not the first or alone) is the basic physical principle of flying. No more and no less. This can not be compared with the complicated technology or even rated. The technology used coordinate systems, which are favorable for them. E.G. order to make the math easier. A physical theory must, however, use the coordinate system, which is determined from the nature for this event.
Read New Theory of Flight and you will understand that flight is form of
miracle and not a triviality.
You can be shure, I know all of them.
What as discussed previously, is only the half of the problem. How flies a bumblebee? It must also have the same theory with in it self. Only a theory that can that, can also be right. This also applies to the sub-and supersonic flight, too, they must have force from the same basic principle.
The problem today, to understand how to fly properly, is not in the difficulty of understanding a new theory, the difficulty is to get out the wrong in the head and to recognize the right or wrong.
The physical criteria that identify theories as right or wrong, is no mathematical result. Even false theories provide mathematically correct results. For gravitation alone there are five different theories that come with five differnt math still the same results. And all are wrong, none can say what gravity is.
The accuracy of a physical theory proves itself in that they can answer all questions without hesitation directly by the basic principle. Check out the different theories.
Without new thinking no new knowledges, it´s my conviction. Karl Popper, Austrian physics philosopher, said: physics is revolutionary, not cumulatively!
I hope that I am not too hard with you.
With greetings!
Peter Apel
Sorry for my englisch!
I really love your blog.. Great colors & theme.
Did you develop this amazing site yourself? Please
reply back as I’m trying to create my very own website and want to find out where you got this from or what the theme is named.
Thank you!
It is a standard wordpress theme: Twenty Eleven
WHO IS RIGHT IN BERNOULLI AND PASCAL
Who is right?
Newton’s Third Law or Bernoulli.
Is Newton’s Law and Bernoulli mutually exclusive?
““What actually causes lift is introducing a shape into the airflow, which curves the streamlines and introduces pressure changes – lower pressure on the upper surface and higher pressure on the lower surface,” clarified Babinsky”
http://www.cam.ac.uk/research/news/how-wings-really-work
Why does this discovery negate Bernoulli?
“the air moves faster over the top surface and has already gone past the end of the wing by the time the flow below the aerofoil reaches the end of the lower surface.”
That’s it?
On the Turn and Downward acceleration:
Flight demonstration teams routinely fly within inches of wing surfaces and the slot flies in very close proximity to the lead wing. Military aircraft routinely refuel in close proximity to tanker wings and fuselage. If Downward is as imagined, flight isn’t possible.
The Cambridge video has it right.
because according to Bernoulli area[pressure] s directly proportional to each another but according ti Pascal P=F/A means pressure is inversly to area? who is correct?
Pingback: Grossly Over-Designed and Over-Engineered | Over-Designed and Over-Engineered
The principal of lift is as simple as angle of attack. Anything that moves air mechanically uses this principal. So an airplane flies by moving air downward through the angle of the wing as differentiated from the forward motion of the wing. The shape of the wing is not essential to this basic principal, but becomes essential in terms of efficiency.
Bernoulli’s law is a moot point because there is always energy being expended at some point anytime an aircraft flies.
Why are we still letting ourselves get confused with OLD and INCORRECT theories?
Hallo,
I was thinking a long time, how it can go forward. The result:
It makes no sense to talk about the contents of theories. Everyone loves or believes his own theory.
What is a physically theory? That was not yet defined, which there exists many wrong theories.
My definition is, that a theory must have including following three points:
1) What will be explained,
2) which operating principle makes the process
3) by which cause to which effect.
Physical theories need to be universal, this is a big law!
This is for flying, that its theory must have a basic principle that applies to all flying objects: for airplanes, helicopters, birds, insects including bumple bee and also for subsonic and supersonic flight.
A physical theory can only be confirmed by physically rules, and that is verbally. Why? Quantitatively correct results provide also by wrong theories, for gravity alone five.
The first test for a flight-theory is, that it must be able to explain the fly in the original. The wind tunnel is a copy of flying, even with the reversal of movements.
How to configure a theory that does not matter, but it must be able to explain an operation in the original. Bernoulli theory can not, because the aircraft is moving, not the air.
This must also take seriously and not sweep off the table with the argument, that it is equal! This “equal” never is universally proven!
The second test is, that the flight theory must can answer directly with its basic principle all questions
Some questions are:
1) Why does the air raises in front of a wing?
2) Why does the wind increase at the top of the wing?
3) Why the vortices are formed with a diameter of the wingspan of the aircraft?
4) Why fall the vortex?
5) Why is there a ground effect?
6) Why is there even a ceiling effect?
7) Why do not produce the two wings of a biplane also double lift?
All answers must start with the basic principle. The answers from the theory by Newton, namely that lift arises from the recoil force downwards accelerated air, are:
To 1) and 2): Because an aircraft wing forces air downward, air swells in front of the wings upward and rearwardly over the wing increasing the relative wind. The increase wind is a real, ie absolute flow, in which even a Bernoulli effect is created, but only by the increasing speed.
To 3) Because an aircraft wing pushes air downwards, it swells also air on the sides of the flight path upwards, which found together with the downwash to a huge vortex. A vortex only by pressure equalization from the bottom upwards around the wing tip would be much smaller and it would not fall, rather the opposite.
To 4) Because an airplane wing pushes air downwards, naturally this fortex continue downwards. Its mass is about the size of that of the aircraft by itself! Caused by the mixing in the wing with air from the side the vortex falls with about half speed than directly on the wing.
To 5) Because an airplane wing pushes air downwards, naturally air dams back, if the wing is dense enough underneath and the pressure under the wing is increasing.
At 6) Because an airplane wing pushes air downwards, air must flow from the top even after. If this hindered by a blanket from the top, the vacuum rises above the wing. This can be observed at each helicopter toy on the ceiling.
To 7) Because an airplane wing pushes air downwards, a second wing near the first can not speed up again the same air from the first. That’s why it does not matter how much blades an impeller has in a centrifugal pump because each blade does the same only.
Anyone can invent a theory, but it has to provide the answers in the same way.
Flying is not a secret, but a for anyone to understanding very simply kinetic process.
Any theory that can’t answer the questions, is definitely wrong. This applies even to the theories of relativity).
With Greatings!
Jan Peter Apel
Please consider Helmholtz and the smoke ring of constant circulation that results from an impulse. The moving wing lift force is the same as applying a series of impulses as the wing moves. The resulting downward moving vortex rings link up to form a hairpin vortex, which is the common contrail. This makes it clear that the double vortex is the flow field from a wing. All of this is explained with drawings and math in http://www.wingswakesandbernoulli.com.
This is FANTASTIC.
I’ve been working on a similar theory for years, but hadn’t had time to sit down and work the math out.
THANK YOU SIR. 😀
In vortexes you can interpret much in and out. Where whirls come from, nobody asks.
Vortexes first must be generated. Vortexes are never the cause for something, but always the result of something.
The basis of all vortexes are the touching area of different moving air masses. That’s all.
In the case of the wings, vortices only arise when the wing generates air masses in a movement in relation to the surrounding air masses.
The air forces arise only by acceleration of air masses. What with the air happens then, whether or not vortexes form, is secondary. If an aircraft flies densely between two rock walls, there is no vortex road. However, the lift is there even greater than in free airspace
Just another thought about introducing viscosity. Does the New Theory with turbulence at the trailing edge result in the well known double vortex wing wake ? The bound vortex theory for a 3D wing in ideal flow automatically gives the contra-rotating wake vortices that conserve Impulse and circulation. The double vortex wake is seen clearly in any contrail, and it persists indefinitely. See my web site and the drawings of the wake. I use only inviscid flow, and Prandtl’s argument of induced drag.
What you are speaking of are the wing tip vortices, which are not the origin of lift, since they are absent for an infinitely long wing with lift.
No. I am speaking of the vortex sheet wake that is the analytical solution for an elliptical wing for the condition where the flow follows the angle of the trailing edge. Look at my web site and you will see that in 2D the force here is always normal to the motion. So, no induced drag. In 3D the lift force moves to the back , giving rise to induced drag, which implies energy addition to the flow in the wake for a moving wing. If viscosity is introduced, that is OK with me. But it implies dissipation in the wake, which is not seen. The sheet wake rolls up into two contra-rotating vortices, which are correctly sized by inviscid theory. These two big vortices persist in the wake virtually unchanged as seen in the ubiquitous contrail. they are very consistent with Euler theory.
What about a long wing? Still “two contra-rotating vortices”?
If there is no viscosity, and there is a lift force put on the fluid, and a wake that is half infinite, then Mr. Helmholtz requires there to be a closed expanding vortex loop of downward moving fluid in the wake. And that circulation and impulse be preserved, which occurs as the sheet transitions to two large vortices. The condition that all the fluid inside the loop moves down at the same velocity is an analytical result of having an elliptical wing planform. This serendipitous feature explains why the Stanford sheet analysis I reference works as well as it does. I suppose that viscosity can be more important for long wings. If the boundary layer does become turbulent for this case, I wonder what 3D turbulence model would be appropriate for an elliptical wing. EQ
Dear claesjohnson
Let me say some truths.
Are educated sly and nonaducated stupid? Most of all are stupid and most of educated can only excellent talk about something, but even does not understand it. To differ people in unaducated or educated makes no sense and is discriminatory.
If a noneducated with interest do not anderstand an explanation, the explanation is wrong.
Why can fly an objekt?
Because it pushes air mass down.
The end.
There is no more to say!
With this basic prinziple alone can explain all, what there is in and arround flying. And that that is possible, is this the only once physical rule, what can say right or wrong to a theory. In this case it say right.
Starting with this basic principle can be found all phenomena that have so far been carried together in a disorderly manner. One must only to will it!
Vortices, in there rotates air particles, arise at all border lines of down pushed air in the surrounding air. On a wing from a bumblebee is this vortex nearly a vortex ring. On an aircraft flying from London to New York is the vortex ring very smal but very long and already died at the starting point. The vortex belongs to the whole closed borderline between the down wash and the surrounding air. On all places, the vortices rotates from the inner area down to the outer up. Therefore, opposing parts of vortices always turn against each other. It is a rumor that there must be always opposed vortecies! It’s only mostly. In all fortices are valid the Hemholtz laws, not only for flying!
And further: to push down air, the air does not need a viscosity! Also that is a rumor!
One must not beleave all, what other say, also not by educated. Either, it is understandable in a stringent line for its own.
The proof: Either, one can explain some circumferentially by own words, at all times (day and night!) without help by any other written, or one has not understood it.
When at last do educated become convinced that running wind is no flow in the sense of physics, in which a Bernoulli effect can arise? So long, as one observe “flying” in the wrong coordinate system (plane and wind chanel), so long are all theories of flight wrong.
If planes fly by pushing air down, is this not an argument for buoyancy? ie. A plane must displace a mass of air equal to its own mass each second, or it sinks. The same reasons why boats float.
Your argument that a wing works by pushing air down was used already by Newton to compute a lift which was 10 times too small and would not allow flight at affordable power. The key is to explain that lift is not that small, and so there is more to say, and I am saying it.
You see my formula for lift by Newton in physicsfuture.org: What is Flying?
More precisely, it is the lift to drag quotient L/D which is 10 times too small with Newton’s push down of air from the lower side of the wing which forgets the suction from the upper side. With Newton L/D is about 1, while the true value typically is 10.
Which mathematician, who has no idea of physics has invented this quotient L/D. And what have it to say in physics? Nothing. What has been invented more mathematically in faith to gain physical insights? All is nonsense.
Of course it is theoretically possible that a wing air pushes down without thereis no resistances in the horizontal direction. Only the “resistance”, which results from the geometry of the inclined plane is not be avoided. Whether there are other resistances that counteract the horizontal movement of the wing, is irrelevant. They only cost more drive power.
Nature does not consist of mathematical “terms”. Natural phenomena work with its involved real things and their mutual interactions. And just like that they are to explain!
Richard Feynman said in “The Character of Physics Law”: “Why would an infinite amount of logic be needed to find out operations in a single tiny piece of space / time? That’s why I hang somehow on the hypothesis that ultimately physics does not require mathematics, that at last the machinery will come to light and will be so easy like the rules of the superficially seemingly complex chess game”. (Its my re-translation-)
Only when the “solution” is clear, math may interfere, to find something more by this basis. Without the right basic mathematics produces only physical nonsense. Physics has nothing to do with mathematics.
The solution to the problem fly is: push down air mass. Any flying object must push air down at each location where it is currently located.
I don’t see that further exchange of ideas will lead anywhere.
Why don’t you just admit the guy has out classed you and slip away
Τhe thing to explain is why a wing displaces air down. That a boat displaces water is obvious.
The wing displaces air down (and slightly forwards) as it has a positive angle of attack. This can be seen by the backwash behind the plane, especially in low flying planes.
“Τhe thing to explain is why a wing displaces air down. That a boat displaces water is obvious.”
Why a wing displaces air down? Because it must do it! But we cannot see it: that’s the problem!
Lift as a force is created by Newton’s UNIVERSALLY law, which must not be ignored: ALL forces occur only through mass times acceleration. Lift is a force by Newton’s law, not a result of academic considerations or views from wrong coordinate systems (wind tunnel).
Paul Dirac said: a physical theory is either short or wrong! The theory by Bernoulli is the longest non-understandable theory in the simple part of physics, the mechanics. Why? Because it is false.
Each theory must have a physical basic principle. Bernoulli’s effect is a nature event and not a nature principle! No nature event can axplained by an other nature event! Any explanations for natural phenomena must proceed from its own most very simple basic principle, in directly and stringent line. So also a flight theory must be easy for noneducated and educated!
Can aducated explain any thing not understandable to everyone whith interest, they do not know themselves.
Jan Peter Apel
I am not overly excited about entering this conversation. But, I would like to point out that in the wind tunnel case lift occurs with no energy addition to the fluid. When the wing moves, there must be energy addition to the fluid from lift because of the force of induced drag times distance. Right or wrong theory, one must account for energy conservation in the wake. The Bernoulli group is total energy. For the steady wind tunnel case, its volume integral must be constant.
Because it must do? Why? Because it must? This is not physics, only circular reasoning.
I did a video on this recently – explaining how buoyancy can explain why planes fly, see: “The Alternative Theory of Flight : A Synopsis.” (8 minutes) https://vimeo.com/175567433
I’d be very interest in any comments or feedback that anyone might have. Thanks.
The link is bad
“The Alternative Theory of Flight” by Nick is correct! Its the same like that by me in http://www.flugtheorie.de and in my book from 2001 “Der wahre Grund des Fliegens” and 2016 “Was ist wahr beim Fliegen”.
To claesjohnson: If an objekt wants to fly, it MUST push air-masses down. That’s the whole theory of flight! More is not necessary! It applies to all types of flights as bumblebee, helicopter, plane, and birds. All other around this are Details. Lift is a force and mechanical forces without Newton are not possible in this world: there are no forces in addition to Newton’s forces.
What makes an object “to want to fly” and then do it?
To explain flying is not, to explain, how a plane does it. The task of explaining flying is, to explain, what the basic principle of flying is. By all physical laws, especially that, that theories must be universal, must be the basic principle absolutely the same for all objects, who can fl, by any nature whatsoever.
The basic principle of flying is: air masses push down. The reaction force of the air masses is lift. That’s all.
What of this is not understandable?
All flying objekts rides on down accelerated air masses. How they can do it, is only a technical problem. And the technology offers several solutions.
Physics is like math: all in it is “must”: also physics know only right or wrong. That todays physics can not do this, is the proof for its falsity, especially in the field of aerodynamics.
I can not help it: the language of physics is a “must”! Can one not use it, then one know nothing.
Dear Mr. Apel,
I’m enjoying your interchange with Mr. Johnson.
In my opinion I can’t agree more with him in that trying to explain lift as “air mass is pushed down” is a mere triviality. Correct, yes, but trivial.
It’s trivial because it doesn’t explain anything. OF COURSE a mass of air is downwashed. That’s just a CONSEQUENCE of the whole miracle of flight but not its CAUSE.
Think of you standing on your feet on the ground. It’s not that *because* you don’t fall through the ground there is a reaction force on your feet. It’s *because* there is a reaction force that you don’t fall through the ground. This is the trivial part. The non-trivial part is explaining WHY the force is there to prevent you to fall through.
An opinion on the whole:
Which physical rule says that a theory must be nontrivial?
So that edjuctions can distinguish from non dedjuctions?
So that knowledge are reserved for edjucations?
Paul Diracs said: a physical theory is either short or wrong!
The length of the new theory for flying presented here is even greater than that of the old.
And, in a physical theory has mathematics nothing to look for, a physically theorie has only to explain. And that can only be done with terms.
Dear Mr. Beneyto,
Let me tackle a clarification.
What have trivial or complicated or aducated or not educated to do with the cause of flying? Nothing at all. It belongs not to the problem. All this decides afterwards, if the cause of flying is clear.
Now a fundament for physical research.
If we only believe what we feel, we are already lost. Although, we feel something right, but we do not believe it: we are accelerated from the floor upwards. This is confirmed by every accelerometer. Also Einstein confirmed this by placing a human in a constantly accelerated elevator in the free universe. This human feels exactly the same as here on the earth’s surface.
However, we are believing something different. Namely, that we should be attracted by an ominous gravitational force from above downwards, which Newton himself did not believe.
What is cause, what is effect?
What is action, what is reaction?
These are the questions of all questions since the beginning of mankind’s thinking. We are still struggling today, particularly in the problem of flying, because we are not able, to find its right coordinate system.
“One can see something so or so,” is in physics absolutely forbidden! One must find out, how something MUST be seen! And that determines the nature.
What is action, what is reaction?
We ask Newton. Masses generates a reaction, if they are accelerated. If we measure an acceleration in/on a body, it is accelerated by an external force, that is an action force. The action force MUST be the first.
The action force ist the cause, the reaction force is the effect.
We feel an the floor an acceleration upwards, this is the reaction.
The fact: we do not push on the ground, but we are accelerated from it upwards, because we can measure the acceleration in/on us.
Accelerations are vectors! But nobody cares. So we MUST be wrong in many things of the nature, and we do.
If air mass flows down behind a flying object, then it must be accelerated before by an action force. This comes from the airplane. It accelerates every second a lot of air down in about the size of its own weight! For the air, the weight of the aircraft is the action force. The plane by itself is accelerated upwards by the reaction of accelerating down of air mass. We feel in the inside of a plane the acceleration upwards like that on the ground. But we declare it wrongly as a gravitationel event.
If we longer not believe measuring instruments, we can slowly give up physics.
Einstein’s explanation of the weight with a man in an accelrationed elevator is one of the few with which he is right, because it is measurable. Everything else of him like space-time is not measurable. The measurables of this world must be explained first, then it can go on to the unmeasurables.
Jan Peter Apel, you are so correct about the aircraft accelerating downward the air surrounding it. If you look at the aircraft wing from afar and think of the wing as making line impulses with elliptical loading, then the downward acceleration over the wing span is uniform. This downward acceleration of the air over the span sets up a series of 3D fields of motion as the wing moves ahead by each dx. In the far downstream wake these 3D impulses resolve into a downward moving 2D field of width equal to the wing span. This is the motion of the air surrounding the flat “wake sheet” prior to roll-up. The effective accelerated mass of this 2D field is called the “added”, or “virtual” mass. Because of the analytics of the fluid motion, the impulse in dx affects a virtual mass of rhoxpix(b/2)squared. Some people in aviation stack think that a circular mass is what has been accelerated, but that is incorrect. Although the virtual mass in 2D has the value of a circle moving uniformly, the actual motions are distributed all the way to infinity. It is only the integration of the total 2D field motion affected by the wing impulse that is fortuitously the same as a circle of diameter equal to the span. Of course as you say, the reaction impulse on the wing for each dx is the lift, which then acts on the total mass of the aircraft to keep it level in the gravity field. Don’t forget that even in this simple system, a moving wing adds energy to the air.
Dear Earl Quandt,
Your last sentence excludes the use of aerodynamic processes according to Bernoulli, because by Bernoulli’s processes no energy flow may be present. That is correct. The mechanics, especially the kinetics, leadsto the cause for the flying prozesses between plane and air mass. It applies only Newton’s law of force.
The mystery of flying does not arise from the fact, that the observed phenomena, such as the supposed circulation, can be mathematically formed, but rather, as the basic principle of flying, ie the generation of lift.
The circulation is real and arised in consequence of generating downward movement of the air mass, so that air escapes upwards in front of the wing and flows backwards on the wing top, which increases the “wind” on top of the wing. But this “wind” is not a real air-flow! Only the part of the upflowing air from before the wing is a real air flow. It produces (even by Bernoulli) only a displacement of the vacuum area from back to front, but no increasing of lift. The upward flowing air in front of a wing is to see in the wind tunnel by the rising smoke filaments in front of a wing. The upflowing air or circulation is a consequence and not a cause for whatever. In supersonic flight it does not exist anymore. The plane flies nevertheless.
Because a wing presses and sucks the air, the considerations of electric fields can be used for mathematical calculations in 2D for the relative air currents (not for the absolute ones!!) as observed in the wind tunnel or shallow water channel.
Considerations in 3D are not necessary or not appropriate for the determination of the cause of the flight or its physical explanation, they only become more complicated, so that the simple basic principle of flying is exaggerated.
An object can fly only therfore, because it accelerate air mass down. That’s the secret of flying and nothing more.
How an object makes this, is its problem.
Jan Peter Apel: Your view that Bernoulli is constant is incorrect. Work is added to the air by the motion of the wing in forward flight. It is easy to see this through the induced drag. Clearly this drag times dx represents work which must appear in the fluid. Bernoulli is constant only for steady processes. This is true in ideal flow. The work is as important to understand as the lift. Good luck.
First: what do you mean with “Bernoulli is constant”?
Sorry, but your meaning is incorrect.
The energy, that a flying object has to expend consists of two basicly different parts. The one, the larger, are the various resistances, which can not measure individually.
The other is the energy required to move air mass downwards by the forwardly moved oblique wings (angle of attack). For this I have found the appropriate formula.
The downwash is measurable behind a flying object, though difficult.
All previous flight theories see this part of the necessary energy input as contained in the resistances, which is wrong. The down wash is treated by the Bernoulli theorists as unimportant, instead it is the secret of flying.
Hi Jan Peter,
I agree. Downwash is key to understanding flight. I did a video on this “Buoyancy Explains Flight.” (15 minutes) https://vimeo.com/175567433
Have anyone managed to measure downwash from a plane?
thanks
Hi Nick,
I do not know if someone has ever made such measurements.
Your video is very very good!
But, I wanted to find it over “vimeo.com”, unavailing. Would it be not much more successful to present it in youtube? I believe, nobody find it in vimeo.
I have found some points that needs to thinking about it.
The term dynamics is not defined. All the world uses it, for whatever obviously. The factually wright term is kinetics. Aerodynamics refers to processes in the air without energy supply or dissipation. Aerokinetics means processes in the air, which involve energy supply and removal.
“Bouyancy is a product of gravity”. How do you mean that?
“Flying though illuminated green smoke”: The further that air is pushed down by fortices”
I think, that the fortices arise by the downwash. It goes down and takes with neighboring air, both entangled with each other. Forticis are always the consequences of differing moving air areas.
“…how a wing affects the air it passes through”
Whoever passes by whom?
In your presentation you let air particles above the wing sink slower then they under the wing. I think, they sink at least as fast. The airspace between the upper and lower air would otherwise be stretched, which I can not imagine. Please look in my page http://www.flugtheorie.de , the english chapter “How flies a plane”.
At last: mathematics can not proof physics! It is a worldly misconception. that mathematics is the supervisor of physics. Physics must lead mathematics in it. A correct theory gives rise to correct physically formulas. Todays physics is full of non physikalies formulas. For example for gravitation. Nobody knows what gravity is, but already there are formulas. Even several for different theories. They all produce only quantitatively correct results, but are not physically underpinned, only based on observations.
Peter
Peter,
Thanks for those excellent comments. I agree with them all. I am making the needed adjustments to the video to include your comments. Once the video is finished, I will put it on youtube. Youtube does allow me to update the video, so it has to be final. There’s an older version already on youtube. I am also doing a summary 5 minute video.
Would you have any suggestions as to how I might get this explanation of flight peer reviewed and published in a scientific journal? I’m trying to promote discussion on this.
Thanks again for the helpful comments; some responses to these comments:
– I defined “dynamic buoyancy” as buoyancy that is active; eg. A plane pushing air downwards constantly. A ship is “static” buoyancy, as it is less active by comparison to the plane.
– “Buoyancy is a product of gravity” explained: Gravity pulls heavier objects downwards. So air / water pressure increases as you move down (towards the centre of the earth). This creates the phenomenon of buoyancy where heavier objects (ships) can float on lighter fluids (water).
– On the vortices; I agree.
– “…how a wing affects the air it passes through” Whoever passes by whom? (I’m not sure what you mean here)
– On the maths; I agree, it is not proof, It only demonstrates that in theory a plane can displace enough air each second to achieve buoyancy.
regards
Nick
Hi Nick
This letter comes from another sender. If they notice that I answer nichr more, please contact me via my Page.
What means “flight peer”?
Publications always fail because no publisher is ready to accept the theories that are against the mainstream. Often they let them evaluate by Prof’s, who then always say nonsense.
The weight of an aircraft represents the action force that accelerates air downwards. In curves it also makes the centrifugal force. So, buoyancy has nothing fundamental to do with gravitation.
The term dynamics will probably longer be selling from the treatment of transactions between wings and air. But it is wrong, because generate buoyancy is a purely mechanical process. And the term kinetics applies to this.
Water skiing is more suitable compared to flying. However, it only needs the bottom side to generate buoyancy.
A wing passes through the air like a sword: they both move, not the air! Therefore, there is also no flow corresponding to the physical definition which has not yet been made. Namely, that it must have a a pressure gradient from its beginning to its end.
The Coanda effect that Anderson has introduced into the problem flying is therefore unauthorized. In addition, the Coanda effect is a phantom!
Can you calculate whith it? No. It is exclusively Coanda’s observation, that air attaches itself to receding contours. This is expected in a diffuser as a matter of course. So why not on other places?
But, if water flows tangentially to a rounding, it will stick to it for a disproportionate length, even ascending on a bottle. The explanation is: A flow remains attached to a retreating surface as long as it manages to flush away other air sticking on it.
Aber: fließt Wasser tangential an eine Rundung, so bleibt es unverhältnismäßig lange an ihr haften, an einer Flasche sogar hinten aufsteigend. Die Erklärung ist:
Eine Strömung bleibt so lange an einer zurück weichenden Oberfläche haften, wie sie es schafft, andere an ihr haftende Luft weg zu spülen.
This is not the case with airflow against air. In water against water (ie under water) also not. But with water against air! This is, why we see this amazingly long-lasting “sticking” of water to curves.
For an explanation of the downward pressure of air through the top of a wing, this is not suitable because there is no flow. The ‘top’ sucks the air from above because it creates a free space through its forward movement and its angle of attack.
The air therefore flows vertically from above teh wing downwards and not from the front to the rear along a wings profile. This only looks so in the relative (thus wrong!) view of the moving aircraft.
regards!
Peter
I’m not an expert. I read a short description about why NASA believes that the Venturi theory explaining lift is not correct because the pressures and speeds observed do not match Bernoulli’s principle. They admit that they are not exactly sure what exactly generates lift. Or what percentage of each physical action generates lift. I just have a question that is probably just a novelty.
Have wind tunnel experiments been conducted in a zero gravity environment? I realize that this is probably very difficult. i was wondering if it were possible that gravity could be a component of aerodynamic lift.
Ask NASA to run an experiment in the Space Station.
I beg to differ, Buoyancy explains how planes fly (in 3 mins) https://youtu.be/7Uua3VSzSqY
There is no area in physics that is so cruelly confused and false as the one called aerodynamics. Already the name is wrong, it is in fact aerokinetics. Aerodynamics is a process without energy supply and removal. Aerokinetics is a process with energy supply, from a plane to the air. Can one fly without energy supply?
Aero”dynamics” does not adhere to any physical principles, not even to Newtonian physics, according to which forces are generated by impulse changes and by nothing else.
No one can test flight theory, according to what physical principles? But above all, what you are looking for is not to be seen! So the only visible, the smoke in the wind tunnel, is used as the basis of the thinking. Bernoulli in front, Bernoulli behind, Bernoulli everywhere. Bernoulli became the physics of flying. The Bernoulli effect, however, is not a physical principle, but a physical phenomenon, next to the flying. To explain one natural phenomena with another is forbidden in physics, if one takes them seriously. Every natural event has its own processes.
In aerodynamics everyone is reliant on faith, since nothing is comprehensible. There is only “blind” measurement in the wind tunnel.
What does gravitation have to do with flying? Physically nothing, an aerokinetic process runs with the only two involved objects, air and plates. The aerokinetic process produces an air force in order to bring about an acceleration of the aircraft upwards, which counteracts the fall acceleration so that an aircraft remains at its height. The acceleration upwards pushes us into the seats, which we perceive as weight.
Air force and buoyancy must be distinguished.
Air Force is the force generated by a wing (whether in the normal or supine position) by its applied movement with an angle of attak against the air. It is always perpendicular to the surface surfaces, not vertical. A surface pushes air through its angle of attack to the side, in the case of a rudder blade of a ship like a plane of an airplane. In the latter, the “side” is directed only downwards. The energy goes from the wing to the air, air is accelerated to the side or downwards. All this is not seen,therefore not believed.
Buoyancy is only the vertical component of the air force that opposes the direction of action of gravitation. Buoyancy is not a physical quantity in the physics of the air force development, so only what one are looking for in flying. In aerokinetics there is only the air force. This can be divided geometrically into arbitrarily perpendicular components, depending on what one wants to see. Of course, a division into lift and resistance is meaningful, but this has nothing to do with the development process.
Without gravity, exactly the same air force is produced, whether in the air-space of the earth or in space without gravitation, if it were filled with air. The air force results solely from the interaction between surface and air.
The wind tunnel is a physical reversal of flying, the energy is put into the air, so that the relative sight is generated from the airplane. Relatively is however wrong, only absolute is correct. The term “relative” has been invented to separate right and wrong, but nobody cares about it. Everyone builds up its own theory, who has more to say wins, and the others must believe it, as in the Church.
A flight theory is only then correct, if it can also explain the flight in the original, that is, when the aircraft is moving and the air is at rest. It is not only the drag to overcome, but also the flying by accelerate air masses down at the height of the aircraft weight!
Jan Peter Apel
.
So ….. you don’t know why planes fly? or do you favour a particular explanation?
The only correct explanation is from me to see in physicsfuture.org
Jan Peter Apel
Is there any evidence for this theory of flight? Evidence being a scientific experiment in realistic conditions on a real aircraft. (BTW I couldn’t see any explanation of flight of the website physicsfuture.org ).
In physicsfuture.org, English part, title “What is Flying?”.at the end of the list.
What is a proof in physics?
The physical proof of the correctness of a theory according to the rules of physics (which nobody cares about) is that only a correct theory leaves no question open.
Ask questions and let answer by theories (or me).
Physics or a theory must be able to do this without any experiments. Experiments can only confirm correct theories.
Jan Peter Apel
I disagree. No theory is valid without a valid scientific experiment (independently verified & reproduced, ….). A big problem is that no theory of flight is backed up by experiment. Which is why people still debate this.
In aerodynamics, there are endless experiments. They all are reproducible and produce a funktioning mathematical sucess. But these results did not lead to a consistent theory of flight. These can only be found by thinking. However, a correct theory can never be found from false coordinate systems. And that is the reason, why the Bernoulli-theorie ist wrong.
The correct coordinate system for flying is the natural, not the one created by the exchange of the movements of the air and the aircraft in the wind tunnel. In nature, nothing is the same! The natural coordinate system for flying is the air, no matter whether and how it moves, against which a flying object must generate an air force by using energy that holds it up
A theory defines itself as an explanation (not a description!) of a natural phenomenon from cause to effect by a principle.
The principle of the formation of an air force is Newton’s law of forces. Even if results can be obtained according to Bernoulli, a derivation of air forces must nevertheless be made according to Newton’s laws; they are the basis for forces.
Obviously, a theory must also prove itself in experiments. The Bernoulli-theory, however, is confirmed by nothing, everything must be embellished!
For the lot of questions around flying must be found again and again new explanations. A true theory explains everything out of only one principle, the basic principle. And this must be valid for everything: subsonic flight, supersonic flight, bird flight and insect flight.
A true theory is always build on a basic principle. And theories must be able to predict. Why must people die first to discover the vortexes behind planes?
The flight theory by Newton predicts these vortexes unasked!
There is only one true flight theory: the one by Newton as I put it together.
Jan Peter Apel
Wow! Such a revelation it’s like music to my ears.. thank you for consolidating all these great theorems. It makes perfect sense that not one can fully explian the foundations of flight and further inspires me to continue my work as a blue collar flying/inventing enthusiast. Many kind regards J
The William J. Hughes Technical Center
INVITES YOU TO A
SPEAKER SERIES featuring:
Michael Konyak
Laboratory Integration Lead
Thursday, July 13, 2017 at 1:00 p.m.
Technical Center Auditorium
Title: A Critique of Aerodynamic Theory
Dear Michael Koniak,
unfortunately I can not follow the invitation because I live in Germany and I’m not so rich that I could travel into the USA. Besides, I do not speak enough the English language to lead discussions.
However, the problem of flying does not require a large number of participants. One person alone with the right thinking is enough. But this can not be one that is filled up with today’s ballast in aerodynamics.
That something is wrong is clear to everyone in the subconscious. But the way to the right things can never be made in a curve with the past.
A return to that point at which the crucial error was made is required. This was the invention of the wind tunnel with its physical evaluation that it does not matter whether the wing moves through the air or the air past the wing.
The Bernoullite theory fits into the wind tunnel, but not into the original state. Only correct theories can this!
For the technique the exchange of the movements is no matter, physically however not. The explanation of flying is a physical and not a technical matter. Physical solutions can not be found out of the technique or from the bottom to the top. For example, the wing must do something, and not the air does anything by itself against th wing!
All physically that has gone before will be ruined by the right solution. The Austrian British philosopher and physicist Karl Popper said correctly, that physics is not cumulative but revolutionary.
Whether a physical theory is right or wrong is not decided by the technique or even mathematics, but solely by its ability to answer ALL questions out of itself. This is the rule of physics for the correctness of theories.
In nature, all phenomena are based on trivial causes, and these are principles and never formulas!
Nevertheless, I wish the event the successful finding of the right way and the right theory.
Peter Apel
I have just discovered the debate and wondered if the author is a pilot, otherwise is it a semantic debate. The successful practice and development of aviation during the past 114 years indicates that theories are successfully applied. I teach aeronautical engineering and also gained my pilots licence in 1972. I regularly fly and instruct pilots, applying theories to practice – the key word is theories
It’s wonderful that you’re an instructor. I was a pilot, only gliding, but a flight instructor. But that does not matter, on the contrary: pilots are so deeply involved in their view of things that they lack any neutral overview. That’s why the flight problem can not be solved by insiders. Furthermore, I am an engineer in mechanical and electrical engineering. And then I’m a self-taught physicist (pysicsfuture.org), head over things!
All previous theories of flight are adapted to observations from the wind tunnel In the wind tunnel, however, the movements are reversed: not a wing moves as in real nature, but instead the air, which it does’d in nature, ie in the original, whereby the air flow is a variable size. Theories may only contain invariant varables. From the wrong wind tunnel view, which delivers technically correct values, can never develop a correct theory. Technology is not physics, just as mathematics is not physics.
In the wrong coordinate system of the wind tunnel all previous theories are locked. NASA has correctly stated that none of these theories are correct. Only the right one it does not have, but I.
The physical criteria for correct theories are:
1. It must not leave any question unanswered.
2. It must be able to answer more questions than led to their finding.
3. The answers must all derive directly from the basic principle determining the process. The basic principle of flying is air mass permanently pushing down for the “ride” on there recoil force.
Bernoulli or Coanda effect are not functional PRINCIPLES, but their own natural phenomena to be explained BESIDES flying.
Please ask me questions about flying, which I will answer to you understandable with the basic principle of flying.
i wonder why you my comment has not been published. i hope this 1 will. just take your hand out of the window of your car while in motion. close your fingers as you were signaling for turn. twist your wrist so you increase or decrease the angle. when held horizontal you fell only drag pulling it backwards. now begin to increase the angle of attack and you will feel your hand raising: that is lift. and you feel the pressure on the bottom. no matter what shape of the airfoil, there is how a surface produces lift. of course the airfoil pays a role in the efficiency, but the main factor is the angle of attack.
To keep out the hand out of the car as a wing: then we are with Adam and Eva of aviation. Unfortunately, there is also an apple, the physical sin. And where is it? In the head of the owner of the hand.
How that?
The head of the owner of the hand thinks, that the air is doing something with his hand, namely pushing it upwards by an angle of attack.
Completly wrong!
Not the hand is pushed up, but it pushes air downwards, so that the reaction force of the air mass generates the force up on the hand.
What does the physically devil say? It says: It does not matter if the hand moves in the air or the air moves along the hand.
If that really does not matter (it does not matter for technical measurements, but not for physics), then that means also that with the consideration that the wing moves through the still air, the same result must come out.
But it does not, which definitely refutes this egoality. In physics, so in nature, nothing is equal, everything is determined (by God?).
What is that little devil between ears?
The self-glorification. Humans intuitively assumes that he would set the zero point or reference point or coordinate system for his observed or perceived. He is never afraid to feel like God.
When he holds his hand out of the car, the air moves past his hand. He does not
care how the air sees it. The fact, that his hand actually moves with him in the car is unimportant for him, he always sees himself as a supervisor, never just a participant in a natural phenomenon. And that is the original sin of aerodynamics, which is in reality an aerokinetic.
If my theory of flying, which is based on the movement of the wing and not on one of the air, is wrong, then you can refute it. I even ask for it and also donate a price, see my Page http://www.flugtheorie.de in the German part.
there are some real problems with your theory. some of your nomenclatures are incorrect.
I’m not going to debate with you, just thinking that you should/need to rethink this?
You think downwash is lift, ok… if an aircraft weighs 100,000 lbs there would be 100,00 lbs of downwash. have you ever stood at the end of a runway as an aircraft lands? as it passed over you you would feel that force. guess what…..i have done this. i think you can answer that on your own.
check out the wind tunnel tests on airfoil….very little downwash, keep the discussion going!
I know, that you can not feel anything under an airplane during its deep overflight. The air can not flow into the ground, so it flows to the side. Very near to a runway small aircraft were overturned by big ones landings and in the Antarctic penguins fall to the sides.
The problem is, that the down wash on the floor is not noticeable and that’s why there are the wrong theories.
Down wash is not a lift, but creates the lift, from the recoil force down accelerated air.
Then check out the model of the airbus 380, where it moves freely through the smoke screen. in the middle between the big vortexes you can see the intense downward movement of the air.
Some see this, others do not.
1-lift is the ‘up’ force that a surface generates when moving into a fluid at a positive angle of attack.
(or wind moving around a fixed surface, like in a wind tunnel). pressure on the under surface, suction on the upper surface. that easy.
2-the fluid has density. this factor is just ignored.
3-chinese flew kites for thousands of years without knowing this, but it works.
and kites are flat surfaces at a positive angle of attack, that wind flows through. is the equivalent of a surface moving through static air.
bernoullis theory does not work because the surface is moving through open air, not in a duct where air gets compressed. that is why wind tunnels dont bring exact data and planes have to be tested in open air to learn the exact behavior.
a particle running through the upper surface and another under dont match at the trailing edge. that is not true. that works only in ducts, not in open air.
enough!