Debunking Lift Theories Still Taught

[completeaerogeek]

Yes you

 

Your NASA link in the first post is only debunking the "equal transit" portion of the theory, and says that many aspects of the Bernoulli's theory are correct in relation to lift production. It was my understanding that making lift was a bit more complex than "it's ALL this, or it's ALL that", and that both the low pressure on top and the reactive force from deflection, create lift.

You are correct but at the level we need to know it, it is quite simple.

 

The two principles are intimately connected but it is a fact that turning flow causes lift. The pressure fields are a RESULT of changing the direction of flow. Use a flat wing in NASA's FoilSim to prove it to yourself. Flat wing-Zero AOA=no lift. Flat wing 7 degrees AOA L:D ratio of 9:1. In research it is always best to go to the simplest example of what proves your explanation.

 

Some aspects of Bernoulli's theorem can be used but only as an approximate because air is not Inviscid as he assumes. Also Bernoulli is derived from Newton's second law so why not make it simple and use Newton. The problem is not Bernoulli's theorem per se, it is the kooky explanations people use when they don't actually understand what Bernoulli's theorem demonstrates.. That is why people use a Venturi as an explanation and this is What Bernoulli's theorem was designed to explain but a wing is not and never will be a venturi

 

If you read the explanation of Conservation of momentum/flow it can only occur in a closed system like a venturi.. A wing is an open system. Also Bernoulli's calculations only apply along a single streamline not across the whole flow field around a wing.

 

The last an most dangerous part for pilots is that it is easy to imagine air being acted on by a ceiling fan or a kite or a hang glider. The two flows across the surfaces are easy to interpret and give an accurate picture. If you mention Bernoulli, most people don't understand it and make up all kind s of weird stories Like Equal Transit Time or the 'Venturi' effect to explain what happens a there we go astray.

 

if you like you can do an experiment with your fellow pilots. Ask them if the air speeds up across the upper half of a wing. I am willing to bet most say yes. But if you look at the Cambridge video, you find that relative to the static air it actually slows down. Really messes with the explanation doesn't it?

 

I hope this was helpful.

 

 

[Head in the clouds]

As a few folks have mentioned, knowing how a wing generates lift really doesn't make any difference at all to someone flying the aircraft, except in the case of the fundamental differences between helicopter/VTOL operations and those of fixed wings. Consequently this discussion doesn't really belong here in student pilot forum. Earlier mention of persons attending ATPL courses and discussing this is also a bit bewildering since the very basic aspects of aerodynamics are covered in BAK during ab-initio training and are of little consequence further down the track. Whether an airline jock is atop a supercritical airfoil or a Clark Y makes no difference to him, he operates according to the POH.

 

Further - at the end of the day the generation of lift via varying methods and foil types is a subject for the trainee aeronautical engineer and really doesn't matter a jot to the trainee pilot. The only relevance to the pilot is the slightly differing stall characteristics between them.

 

What is of far more concern though is the sort of mythology that I questioned a few posts back and which is clearly still being promulgated by those very same folk whose mission is claimed to be to debunk the flawed teachings.

 

I asked our worthy Prof (see post #70) to expand on a comment in his course notes which states -

 

Here the aircraft is rolling and turning to the left. Ailerons

 

work opposite to each other to roll the aircraft. Rudder is

 

used to assist the turn and prevent skidding.

 

As the regular readers of this site will be well aware, the above seeks to promote the use of mishandling techniques which are statistically our biggest killer of all. Though he's buried his response in my quote, the Prof responded -

 

Now as to adverse yaw-the tendency for the wing on the outside of the turn to have increased induced drag and pull the nose towards the outside of the turn which is then balanced with rudder into the turn... Would you explain which part of this is incorrect?

I'm not sure whether my tears were from mirth or sheer bloody frustration that this sort of fatally dangerous mythology is still being taught - and by a University lecturer to boot ... but it does amply demonstrate the dangers of having people teaching theory who, by their own admission, have no practical knowledge of their subject.

 

aerogeek, operating according to your statement promotes these kind of events -

 

 

In what way can the above be in any way described as "most dangerous"? There is absolutely no danger whatsoever in a pilot having no knowledge of at all of Bernoulli, Transit Times, Venturis or any other matters of flow across a foil. It doesn't matter to pilots, the most they need to know is just a little about the various stall characteristics that different foils and surface conditions might cause. You should be lecturing to aeronautical engineering students ...

 

 

[completeaerogeek]

As a few folks have mentioned, knowing how a wing generates lift really doesn't make any difference at all to someone flying the aircraft, except in the case of the fundamental differences between helicopter/VTOL operations and those of fixed wings. Consequently this discussion doesn't really belong here in student pilot forum. Earlier mention of persons attending ATPL courses and discussing this is also a bit bewildering since the very basic aspects of aerodynamics are covered in BAK during ab-initio training and are of little consequence further down the track. Whether an airline jock is atop a supercritical airfoil or a Clark Y makes no difference to him, he operates according to the POH.Further - at the end of the day the generation of lift via varying methods and foil types is a subject for the trainee aeronautical engineer and really doesn't matter a jot to the trainee pilot. The only relevance to the pilot is the slightly differing stall characteristics between them.

 

What is of far more concern though is the sort of mythology that I questioned a few posts back and which is clearly still being promulgated by those very same folk whose mission is claimed to be to debunk the flawed teachings.

 

I asked our worthy Prof (see post #70) to expand on a comment in his course notes which states -

 

Here the aircraft is rolling and turning to the left. Ailerons

 

work opposite to each other to roll the aircraft. Rudder is

 

used to assist the turn and prevent skidding.

 

As the regular readers of this site will be well aware, the above seeks to promote the use of mishandling techniques which are statistically our biggest killer of all. Though he's buried his response in my quote, the Prof responded -

 

I'm not sure whether my tears were from mirth or sheer bloody frustration that this sort of fatally dangerous mythology is still being taught - and by a University lecturer to boot ... but it does amply demonstrate the dangers of having people teaching theory who, by their own admission, have no practical knowledge of their subject.

 

aerogeek, operating according to your statement promotes these kind of events -

 

________________________________

Perhaps you should hold your tears of mirth for a minute and stop being to bombastic. You embarrass yourself.

 

Your behaviour demonstrates exactly why we need to educate our pilots because yours is clearly lacking. Hubris is unprofessional and dangerous.

 

You have demonstrated confirmation bias, one of the most problematic characteristics for pilots. You are open only to your own opinion.

 

Here is you misquoting me: Allow me to quote you " You're saying that the outer wing of a turning aircraft has more induced drag than the inner. That can only be because of the difference in speed of the two wings, right? A faster (outside) wing is producing more lift so it's producing more drag, that's your premise isn't it? Have you ever thought about how much the difference in speed (and therefore drag) actually is?

 

Actually I said no such thing. This is you quoting you...It is clear that you like the sound of your own voice.

 

Here is what I said: Now as to adverse yaw-the tendency for the wing on the outside of the turn to have increased induced drag and pull the nose towards the outside of the turn which is then balanced with rudder into the turn... Would you explain which part of this is incorrect?

 

Here is a little something from Princeton University for you: An unwanted side effect of aileron operation is adverse yaw—a yawing moment in the opposite direction to the roll. Using the ailerons to roll an aircraft to the right produces a yawing motion to the left. As the aircraft rolls, adverse yaw is caused primarily by the change in drag on the left and right wing. The rising wing generates increased lift which causes increased induced drag. The descending wing generates reduced lift which causes reduced induced drag. The difference in drag on each wing produces the adverse yaw. There is also often an additional adverse yaw contribution from a difference in profile drag between the up-aileron and down-aileron.

 

So the statement in my notes is correct -as it should be because if you had bothered to read my posts you would have seen that it is credited to the FAA PHAK.

 

All of this ad hominem attack that you seem to enjoy only exposes you as a buffoon. You have not been able to factually challenge anything I have said. All you have done is spout bluster and nonsense.

 

Your kind of behaviour is dangerous because it says to young pilots, you don't need to understand what it gong on, just program the FMC and ask for a coffee.

 

Being that almost all airline accident are due to pilot mishandling these days, a responsible person would be encouraging young pilots to be professional aviators not cowboys as you seem to be.

 

My young BSc ATPL students are very keen to understand how their aircraft works as they should be.

 

You do them a huge disservice.

 

 

[completeaerogeek]

As a few folks have mentioned, knowing how a wing generates lift really doesn't make any difference at all to someone flying the aircraft, except in the case of the fundamental differences between helicopter/VTOL operations and those of fixed wings. Consequently this discussion doesn't really belong here in student pilot forum. Earlier mention of persons attending ATPL courses and discussing this is also a bit bewildering since the very basic aspects of aerodynamics are covered in BAK during ab-initio training and are of little consequence further down the track. Whether an airline jock is atop a supercritical airfoil or a Clark Y makes no difference to him, he operates according to the POH.Further - at the end of the day the generation of lift via varying methods and foil types is a subject for the trainee aeronautical engineer and really doesn't matter a jot to the trainee pilot. The only relevance to the pilot is the slightly differing stall characteristics between them.

 

What is of far more concern though is the sort of mythology that I questioned a few posts back and which is clearly still being promulgated by those very same folk whose mission is claimed to be to debunk the flawed teachings.

 

I asked our worthy Prof (see post #70) to expand on a comment in his course notes which states -

 

Here the aircraft is rolling and turning to the left. Ailerons

 

work opposite to each other to roll the aircraft. Rudder is

 

used to assist the turn and prevent skidding.

 

As the regular readers of this site will be well aware, the above seeks to promote the use of mishandling techniques which are statistically our biggest killer of all. Though he's buried his response in my quote, the Prof responded -

 

I'm not sure whether my tears were from mirth or sheer bloody frustration that this sort of fatally dangerous mythology is still being taught - and by a University lecturer to boot ... but it does amply demonstrate the dangers of having people teaching theory who, by their own admission, have no practical knowledge of their subject.

 

aerogeek, operating according to your statement promotes these kind of events -

 

________________________________

Perhaps you should hold your tears of mirth for a minute and stop being to bombastic. You embarrass yourself. Your behaviour demonstrates is exactly why we need to educate our pilots because your s is clearly lacking.

 

Next before you get too narky - almost everything you have expressed here is your opinion.

 

You have demonstrated confirmation bias, one of the most problematic characteristics for pilots. You are open only to your own opinion.

 

Here is you misquoting me: Allow me to quote you " You're saying that the outer wing of a turning aircraft has more induced drag than the inner. That can only be because of the difference in speed of the two wings, right? A faster (outside) wing is producing more lift so it's producing more drag, that's your premise isn't it? Have you ever thought about how much the difference in speed (and therefore drag) actually is?

 

Actually I said no such thing. That is you quoting you...

 

Here is what I actually said: Now as to adverse yaw-the tendency for the wing on the outside of the turn to have increased induced drag and pull the nose towards the outside of the turn which is then balanced with rudder into the turn... Would you explain which part of this is incorrect?

 

 

 

It appears that you like listening to yourself so much you repeat things no-one has said.

 

Here is a little something from Princeton Universty for you: An unwanted side effect of aileron operation is adverse yaw—a yawing moment in the opposite direction to the roll. Using the ailerons to roll an aircraft to the right produces a yawing motion to the left. As the aircraft rolls, adverse yaw is caused primarily by the change in drag on the left and right wing. The rising wing generates increased lift which causes increased induced drag. The descending wing generates reduced lift which causes reduced induced drag. The difference in drag on each wing produces the adverse yaw. There is also often an additional adverse yaw contribution from a difference in profile drag between the up-aileron and down-aileron.

 

So the statement in my notes is correct (as it should be because if you had bothered to read my posts you would have seen that it is credited to the FAA PHAK.

 

We need to educate our pilots so that we don't end up with a generation of cowboys who only listen to themselves.

 

All you have done here is demonstrate hubris and arrogance. You have not been able to factually challenge anything I have said.

 

You seem to be saying to young pilots- don't worry about how it all works, just program the FMC and ask for a coffee.

 

Given that virtually ALL airline accidents these days are caused by pilot mishandling- often caused by a lack of systems knowledge your statement is stunning.

 

My BSc ATPL/CPL students are actually keen to know as much as they can about their aircraft, They are acting professionally as all responsible pilots should.

 

Instead of encouraging people to be professional aviators you attack people like me who are trying to educate them.

 

Again you have not been able to factually counter anything I have stated- rather you have perpetuated ad hominen attacks to disguise you ignorance.

 

Arrogance and hubris are real dangers in aviation. You should be ashamed.

 

 

[geoffreywh]

For my part (however small) I think that it is critical that pilots know how a wing works, how lift is "generated" (actually, it's not generated as such, is it? but is a by-product of AOA )...I learned to fly very late in life, but had an enormous advantage in having flown contest FAI glider (and some power) for 30 years...I already knew what happened. I believe if people KNEW what was happening as they were flying along or in a circuit then the incidence of stall/ spin accidents would be considerably lessened. ......

 

 

[turboplanner]

We could just delete Bernoulli and make it much easier!

In spite of some conditional and selective statements, I see a number of people who have fallen for the bait, and think Bernoulli's work is irrelevant.

In high power to weight aircraft, and military aircraft a lot of power creates enough force to a virtually flat surface to overcome gravty. The same applies with RC aircraft where the power to weight ratio can be enough to overcome gravity on the prop alone.

 

We, however fly aircraft with low power and cambered wings, so rather than being sucked in by the cherry picking which has been going on, I'd suggest people buy the book "Aerodynamics for Naval Aviators" NAVWEPS 00-80T-80, Naval Air Systems Command, United States Navy. They actually fly aircraft.

 

This publication covers in huge detail flight from subsonic (where we fly) through trans-supersonic to the very difference principles of Supersonic flight, one of the major differences being that airflow is considered as incompressible for simple study of sub sonic flight, and the more realistic compressible in Supersonic flight, requiring different wing profiles, different design, and different management.

 

It's training supports Bernoulli's principle in terms of subsonic airflow, and Bernoulli's equation.

 

While it may be true that many instructors incorrectly teach Bernoulli, including the Geek who would be happy to totally disregard it, tThis book lays it out as it is without complication, embellishment or confusion with irrelevant flying applications (probably because they are teaching people who fly).

 

The NASA equation fed to us by the geek is a different equation for a different agenda, and maybe could be aimed at some of those errant instructors, but doesn't play a part in relation to what is taught in this book.

 

The NASA author mentioned concern about "longer path" and "equal transit" theories, which I would agree with, but although the last dot point was included on the geek's powerpoint slide he glossed over this most important point, which said:

 

"The upper flow is faster and from Bernoulli's equation the pressure is lower. The difference in pressure across the airfoil produces the lift. As we have seen in experiment #1, this part of the theory is correct." (NASA's bold) . (I don't think he meant all of the lift, just the top part of the aerofoil).

 

It is true that the venturi example does confuse people by introducing a thought of "constriction", but it is only used in this book as one example of the Bernoulli principle, in particular as the design of the air speed indicator. If you like, imagine the venturi cut longitudinally and then unrolled flat, so there is no constriction, or better still go to this link and see examples of Bernoulli in practice away from the complications of complete aerofoils and venturis:

 

 

"Aerodynamics for Naval Aviators" explains that this is a snapshot view to make it easier for people to understand the principle:

 

"All of the aerodynamic forces on a surface are the result of air pressure or air friction.

 

Friction effects are generally confined to a thin layer of air in the immediate vicinity of the surface and friction forces are not predominating forces. Therefore the pressure forces created on an aerodynamic surface can be studied in a simple form which at first neglects the effect of friction and viscosity of the airflow."

 

So if you want to go on and build a precise aerofoil you would do both calculations; it doesn't invalidate the principle.

 

 

[ianboag]

Wow. More heat than light here in some posts ....

 

I can recommend a book ... "the Simple Science of Flight". Henk Tennekes (the author) is a (Dutch) professor of aerospace engineering. I believe he has done a bit of flying too.

 

He talks about the unifying principles that govern flight of all objects bigger than a gnat up to the size of an A380. Energy consumption, lift, drag, most "efficient" airspeeds ... etc etc. Why a 747 is more fuel efficient per seat than a mid-size car (!). Why bigger planes fly higher. Fuel calculations about little birds that fly huge distances. All good stuff. It is written in a fashion that anyone moderately technical can follow - not a textbook, just an interesting read for those of us who would like to understand stuff a bit better.

 

more info at http://mitpress.mit.edu/books/simple-science-flight

 

On lift he says the same as CAG. Lift is the upward reaction to a downward stream of air generated by the wing .... in an open system like a wing there is no requirement for two air molecules that separate at the leading edge to end up next to each other at the trailing edge. There's fluid mechanics maths behind it, but the detail is a bit complex for most of us.

 

I agree that so long as the wing keeps us in the air, we don't really need to know too much about the physics.

 

Good ole aviation. PL exam questions about the % oxygen in the air or UV in sunlight. Mastery of a circular slide rule that was cutting edge stuff in the 1940's. Weather forecasts written in pig latin about the time in London. All stuff every pilot should know.

 

But it does seem bizarre. We are taught that the plane is sucked up into the sky by a low pressure zone on the top of the wing and it just ain't so.

 

 

[turboplanner]

Speak for yourself Ian, if you were taught that a plane is sucked up into the sky by a low pressure zone on top of the wing, that's your problem with your instructor.

 

I've recommended a professional book by the US Navy, and it will cost you about $25.00

 

I'm not going to write out several pages here just to be cherry picked by people who don't want to study theory anyway, but if they are forced to will read just enough to get a pass.

 

The short answer is that the underside of the wing among other factors plays a very significant part, as well as the top.

 

in an open system like a wing there is no requirement for two air molecules that separate at the leading edge to end up next to each other at the trailing edge

Who is arguing this? It's bullsh$t.

 

 

[ianboag]

Speak for yourself Ian, if you were taught that a plane is sucked up into the sky by a low pressure zone on top of the wing, that's your problem with your instructor.

Chill. Calm down. Isn't this where this whole thread started?

 

I've recommended a professional book by the US Navy, and it will cost you about $25.00

Thanks. I'm pretty comfortable with the theory in the Tennekes book. Also professional. I would be very surprised if "your book" and "my book" have any significant disagreement. Also cost something like $25 ...

 

I'm not going to write out several pages here just to be cherry picked by people who don't want to study theory anyway, but if they are forced to will read just enough to get a pass.

Fair enough. In my 20-odd years of uni lecturing (engineering school) I met plenty of the type of folk you describe.

 

The short answer is that the underside of the wing among other factors plays a very significant part, as well as the top.

Yep. AoA and all that ....

 

Who is arguing this? It's bullsh$t.

The people who say that the flow splits, speeds up over the top surface, creates a higher velocity (lower pressure) area before the streams rejoin at the trailing edge. The "suck me up into the sky" folk ....

 

 

[completeaerogeek]

In spite of some conditional and selective statements, I see a number of people who have fallen for the bait, and think Bernoulli's work is irrelevant.In high power to weight aircraft, and military aircraft a lot of power creates enough force to a virtually flat surface to overcome gravty. The same applies with RC aircraft where the power to weight ratio can be enough to overcome gravity on the prop alone.

 

We, however fly aircraft with low power and cambered wings, so rather than being sucked in by the cherry picking which has been going on, I'd suggest people buy the book "Aerodynamics for Naval Aviators" NAVWEPS 00-80T-80, Naval Air Systems Command, United States Navy. They actually fly aircraft.

 

This publication covers in huge detail flight from subsonic (where we fly) through trans-supersonic to the very difference principles of Supersonic flight, one of the major differences being that airflow is considered as incompressible for simple study of sub sonic flight, and the more realistic compressible in Supersonic flight, requiring different wing profiles, different design, and different management.

 

It's training supports Bernoulli's principle in terms of subsonic airflow, and Bernoulli's equation.

 

While it may be true that many instructors incorrectly teach Bernoulli, including the Geek who would be happy to totally disregard it, tThis book lays it out as it is without complication, embellishment or confusion with irrelevant flying applications (probably because they are teaching people who fly).

 

The NASA equation fed to us by the geek is a different equation for a different agenda, and maybe could be aimed at some of those errant instructors, but doesn't play a part in relation to what is taught in this book.

 

The NASA author mentioned concern about "longer path" and "equal transit" theories, which I would agree with, but although the last dot point was included on the geek's powerpoint slide he glossed over this most important point, which said:

 

"The upper flow is faster and from Bernoulli's equation the pressure is lower. The difference in pressure across the airfoil produces the lift. As we have seen in experiment #1, this part of the theory is correct." (NASA's bold) . (I don't think he meant all of the lift, just the top part of the aerofoil).

 

It is true that the venturi example does confuse people by introducing a thought of "constriction", but it is only used in this book as one example of the Bernoulli principle, in particular as the design of the air speed indicator. If you like, imagine the venturi cut longitudinally and then unrolled flat, so there is no constriction, or better still go to this link and see examples of Bernoulli in practice away from the complications of complete aerofoils and venturis:

 

Gentlemen thank you for your thoughtful comments. As I mentioned (and NASA does too) Bernoulli's theorem does give an approximation of the pressure differences on top of the wing. based as it is on Newton's second Law however, the statement that Bernoulli is irrelevant is not to say that there is not some value, just that it c an be dispensed with as an explanation for pilots because it caused more problems than it solves..

 

The mathematical solving for Bernoulli is somewhat inaccurate as it assumes air is inviscid but that was never my point. Just as in many things, most people cannot solve the mathematical equation not is it necessary for pilots but most Flying Instructors (and pilots) cannot explain it, they invent all kinds of silly theories about how Bernoulli applies and this is what has brought me here. In PART 61 CASA mentions Bernoulli and Venturi in the same sentence. This is untenable and I have written to CLARC to say so. As I have said and you know, a wing is not venturi which relies on a closed system to operate. A wing is an open system. In other parts of the DAY VFR CPL syllabus they ask students to explain why the upper surface of the wing generates most of the lift.

 

Again this is a very silly thing to say and reinforces the myths. A SC wing (that most pilots will spend most of their careers sitting on top of) particularly at cruising speed is generating a large proportion of its lift from the underside of the wing. Even the new LSA aircraft are using Symmetrical or SC aerofoils as a drag reduction measure and CASA's statement is barely adequate for high camber conventional wings.

 

The essential thing is this: The pressure differentials that Bernoulli and Newton refer to are a result of AOA (and camber if relevant) not the cause of lift. as such they are a side conversation not the explanation we should be using otherwise you get silly statements like the plane sucks itself up into the air.

 

Moving a solid object through a fluid causes disturbances that result in forces Newton explains without formulas and that anyone can understand.

 

It is not necessary for pilots to solve for lift. it is necessary that they be able to correctly visualise what is happening around a wing as a matter of understanding what is happening and an essential piece of knowledge. to jot do so is to say just because GP dispenses 99.0% of the treatments based on their best guess and without any verifying tests, they shouldn't have to learn biochemistry or anything about pathogens. Just play match the symptom to the drug..

 

If you are designing a wings then calculus is your tool. if you are flying air aircraft, a competent and accurate conceptual understanding of what is happening is essential particularly at low airspeeds.

 

For the last 3 years I have been teaching lift to BSc students without any detail on Bernoulli and it is clear that they have a much better understanding of the flow around their aircraft, how it changes and what it means for practical performance than when they came in believing ETT or Venturi myths both of which are perpetuated by having to explain Bernoulli without understanding it.o say that a correct understanding of lift in a practical sense 'doesn't matter a jot' is just irresponsible.

 

Cheers

 

 

[johnm]

refreshing view point completeaerogeek – you’re like a brand new ball in a bowling alley strking 10

 

I’ll be re-reading it all to try and get a handle on it - thanks

 

 

[completeaerogeek]

In spite of some conditional and selective statements, I see a number of people who have fallen for the bait, and think Bernoulli's work is irrelevant.In high power to weight aircraft, and military aircraft a lot of power creates enough force to a virtually flat surface to overcome gravty. The same applies with RC aircraft where the power to weight ratio can be enough to overcome gravity on the prop alone.

 

We, however fly aircraft with low power and cambered wings, so rather than being sucked in by the cherry picking which has been going on, I'd suggest people buy the book "Aerodynamics for Naval Aviators" NAVWEPS 00-80T-80, Naval Air Systems Command, United States Navy. They actually fly aircraft.

 

This publication covers in huge detail flight from subsonic (where we fly) through trans-supersonic to the very difference principles of Supersonic flight, one of the major differences being that airflow is considered as incompressible for simple study of sub sonic flight, and the more realistic compressible in Supersonic flight, requiring different wing profiles, different design, and different management.

 

It's training supports Bernoulli's principle in terms of subsonic airflow, and Bernoulli's equation.

 

While it may be true that many instructors incorrectly teach Bernoulli, including the Geek who would be happy to totally disregard it, tThis book lays it out as it is without complication, embellishment or confusion with irrelevant flying applications (probably because they are teaching people who fly).

 

The NASA equation fed to us by the geek is a different equation for a different agenda, and maybe could be aimed at some of those errant instructors, but doesn't play a part in relation to what is taught in this book.

 

The NASA author mentioned concern about "longer path" and "equal transit" theories, which I would agree with, but although the last dot point was included on the geek's powerpoint slide he glossed over this most important point, which said:

 

"The upper flow is faster and from Bernoulli's equation the pressure is lower. The difference in pressure across the airfoil produces the lift. As we have seen in experiment #1, this part of the theory is correct." (NASA's bold) . (I don't think he meant all of the lift, just the top part of the aerofoil).

 

It is true that the venturi example does confuse people by introducing a thought of "constriction", but it is only used in this book as one example of the Bernoulli principle, in particular as the design of the air speed indicator. If you like, imagine the venturi cut longitudinally and then unrolled flat, so there is no constriction, or better still go to this link and see examples of Bernoulli in practice away from the complications of complete aerofoils and venturis:

 

_________________

 

MR Turbo Planner I am going to quote you here because again you have made a pejorative statement about me justified by nonsense.

 

You a really are quite a dab hand at embarrassing yourself: A very good example that a little knowledge (very little in your case) is a dangerous thing.

 

CAG "Well SC wings were a real change maker. Curved on the bottom and flat on top. Messes with some people's heads!

 

 

 

Turbo planner: "This describes the wings used on Sprint Cars which do such a great job of clamping 850 horsepower cars DOWN on to the track surface, so the geek has some studying to do.

 

 

 

Supercritical wings were introduced originally to help break the sound barrier and are irrelevant to RA and GA flying and irrelevant to supersonic flying, and seem to have been used just as distraction by the geek."

 

There are so many things wrong with this statement it is hard to know. This is the kind of thing that prove 'a little knowledge is dangerous thing)

 

Firstly: Spoilers used on sprint and F1 Cars for that matter are curved plate aerofoils. The turn flow upwards to create downforce. Nothing contradictory there. Simple Newtonian Physics.

 

Secondly, SC aerofoils were NOT introduced to ‘try to break the sound barrier. The X-1 had a thing symmetrical aerofoil and exceeded M 1.0 in 1947. You have misinterpreted the WIKI article you read to make this statement.

 

The next transonic aircraft- the F-86 had a symmetrical aerofoil. (as did most military aircraft at the time and for many years)

 

SC wings in fact were designed in the 1960s by NASA scientist Richard Whitcomb (who also gave us winglets).

 

The SC wing is designed to minimise the angular change of flow over the upper surface of the wing thus reducing density changes that happen when the air ‘turns the corner’ of the leading edge. Density is directly related to the speed of sound so when density drops, the local speed of sound drops causing standing shock waves. This is the basis of MMO and MCrit.

 

As all airliners cruise in the transonic range (above M 0.8) this reduces drag and much improves efficiency.

 

In terms of light aircraft using wings with SC characteristics again Mr Planner you are quite wrong.

 

Attached is the wing profile of a Piper Tomahawk (not even a new aircraft)

 

Many performance LSA aircraft are now using symmetrical or SC style aerofoils as a drag reduction measure just as the P-51 (close to symmetrical did many years. The Canberra has a symmetrical wing so when you try to explain bogus theories about wings flying because they curved upper surfaces and flat undersides, they are proven to be nonsense. Either a physical principle fits all of the criteria in all normal examples or it is bunk.

 

Lastly- you seem not to be able to interpret academic language as you have misinterpreted what the Naval Aviator text is saying.

 

Friction (form drag) is indeed confined to the boundary layer but viscosity is not. If it was the streamlines above the boundary layer would not be affected by the change in velocity (speed and direction) of the boundary layer. Watch the video again or see attached.

 

What the text is saying is: that in order to study the flow field 'attached to the wing surface' you can ‘neglect’ - not invalidate) the friction in order to make it simpler.

 

Now given that most student pilots want to fly for airlines where they will be sitting on top of an SC wing, and that the factual and accurate understanding of flow around an aerofoil is the same whether you are flying an A380 or a J-170 – and that I introduced the SC aerofoil discussion to debunk the idea that wings have to have a 'curved upper surface‘ and that lift created by the curved upper surface ‘sucks the plane into the sky’

 

What part of this discussion is a ‘distraction’?

 

 

 

 

[aro]

A lot of this thread is like one person arguing that red traffic lights mean stop, others arguing that green means go. Newton, pressure, bernoulli etc all exist and all play a part. What is wrong is many of the oversimplified explanations generated by people who didn't properly understand it in the first place. People tend to seize the first one they think they understand and promote that as the right answer.

 

• Newton: is a law of the universe. It is not optional. Lift force is generated by accelerating a mass of air downwards. There is nothing else it can come from. Whatever other explanation is used, Newton is involved.
   
   
   
  
• Pressure: lift comes from a difference in pressure between the top and bottom surfaces of the wing. There is nothing else acting on the wing that can cause lift. It doesn't really matter whether the pressure below increases or the pressure above decreases, it is the difference that matters. The difference in pressure caused by the wing causes air above and below to accelerate downwards, which is required for the lift force. Likewise the acceleration produces the pressure difference. This sounds paradoxical, but the law is "every action has an equal and opposite reaction" - since they are equal and opposite, you can call either the action, and the other the reaction.
   
   
  
• Bernoulli: The air over the top of the wing is travelling faster and has lower pressure than the air below, so this is consistent with Bernoulli. However Bernoulli is based on conservation of energy. I suspect energy is transferred from the higher pressure areas to the lower pressure areas in the act of accelerating the air, which would tend to invalidate the assumptions. Bernoulli applies as far as the bernoulli conditions are satisfied, but we don't have equal transit time, and the air doesn't always (usually doesn't?) split exactly at the leading edge. The classic explanation of the bernoulli effect is a venturi, but this is not the only situation where it applies. It's just an example that has been used and abused.
   
   
  
• Air deflected by the lower surface: Air pressure is a result of the number and energy of molecules bouncing off the surface. A higher pressure has more molecules or more energetic molecules bouncing off the surface. So this explanation is really just a different way of saying that the bottom surface has a higher pressure than the top surface.
   
   
  

 

 

Some other observations:

 

• Lift from a flat plate: Have a look at the streamlines around a flat plate producing lift. The pressure field starts to deflect the air ahead of the plate, causing the airflow above and below to be similar to a basic airfoil.
   
   
  
• Symmetrical airfoil: similar to flat plate i.e. the airflow above and below is NOT symmetrical
   
   
  
• Airfoil shape: The purpose is to precisely control the flow of air around the wing to reduce drag, to prevent it from detaching (stalling) over a wider range of angles of attack, and to control where along the chord the acceleration occurs, which influences the pressure distribution (centre of pressure) and how it changes at different angles of attack.
   
   
   
  
• Supersonic? Way beyond my knowledge, but I think one of the keys is to shape the top surface to avoid the airflow detaching, without the influence of the changing pressure ahead of the wing modifying the airflow.
   
   
  

 

 

You really need to know very little of this to fly an aircraft. You need to know the effect of speed on lift and drag, why the wing stalls and what happens, the effect of surface contamination etc. Newton, Bernoulli etc are really irrelevant to the task of flying an aircraft. They are taught badly, without real understanding, and I think most pilots are confused.

 

* Aerodynamics is complex. I have been interested and learning about it as a hobby for 30+ years. Year 12 physics and chemistry is very helpful but the more I learn, the more I discover that I don't know. These explanations probably also have errors and inaccuracies. I have concluded I have no hope of understanding it properly, unless one day I go back to uni and study it at a tertiary level. Luckily, that level of knowledge isn't required to fly an aircraft.

 

 

[completeaerogeek]

In high power to weight aircraft, and military aircraft a lot of power creates enough force to a virtually flat surface to overcome gravty. The same applies with RC aircraft where the power to weight ratio can be enough to overcome gravity on the prop alone.

 

This is my favourite bit.

 

It shows a stunning lack of understanding.

 

How lift works has nothing to do with how much 'power' you have.

 

100,000LB of thrust at 0 AOA with a flat plate wing will not create ANY lift.

 

Lift only required energy create movement.That energy can come from gravity (a glider) or an engine. A paper plane is the most basic form of a flat wing. It has no thrust (other than your hand) and flies very well.

 

You have completely missed the point that a flat plate is the simplest kind of aerofoil and works by exactly the same laws as any other aerofoil. If turns the air creating a reaction force. A kite does not require any thrust, just the relative motion of the air.

 

I think for the sake of what little credibility you have left, you should retire and ponder what we have discussed. You are just digging a bigger hole…

 

 

[completeaerogeek]

A lot of this thread is like one person arguing that red traffic lights mean stop, others arguing that green means go. Newton, pressure, bernoulli etc all exist and all play a part. What is wrong is many of the oversimplified explanations generated by people who didn't properly understand it in the first place. People tend to seize the first one they think they understand and promote that as the right answer.

• Newton: is a law of the universe. It is not optional. Lift force is generated by accelerating a mass of air downwards. There is nothing else it can come from. Whatever other explanation is used, Newton is involved.
   
   
   
  
• Pressure: lift comes from a difference in pressure between the top and bottom surfaces of the wing. There is nothing else acting on the wing that can cause lift. It doesn't really matter whether the pressure below increases or the pressure above decreases, it is the difference that matters. The difference in pressure caused by the wing causes air above and below to accelerate downwards, which is required for the lift force. Likewise the acceleration produces the pressure difference. This sounds paradoxical, but the law is "every action has an equal and opposite reaction" - since they are equal and opposite, you can call either the action, and the other the reaction.
   
   
  
• Bernoulli: The air over the top of the wing is travelling faster and has lower pressure than the air below, so this is consistent with Bernoulli. However Bernoulli is based on conservation of energy. I suspect energy is transferred from the higher pressure areas to the lower pressure areas in the act of accelerating the air, which would tend to invalidate the assumptions. Bernoulli applies as far as the bernoulli conditions are satisfied, but we don't have equal transit time, and the air doesn't always (usually doesn't?) split exactly at the leading edge. The classic explanation of the bernoulli effect is a venturi, but this is not the only situation where it applies. It's just an example that has been used and abused.
   
   
  
• Air deflected by the lower surface: Air pressure is a result of the number and energy of molecules bouncing off the surface. A higher pressure has more molecules or more energetic molecules bouncing off the surface. So this explanation is really just a different way of saying that the bottom surface has a higher pressure than the top surface.
   
   
  

 

 

Some other observations:

 

• Lift from a flat plate: Have a look at the streamlines around a flat plate producing lift. The pressure field starts to deflect the air ahead of the plate, causing the airflow above and below to be similar to a basic airfoil.
   
   
  
• Symmetrical airfoil: similar to flat plate i.e. the airflow above and below is NOT symmetrical
   
   
  
• Airfoil shape: The purpose is to precisely control the flow of air around the wing to reduce drag, to prevent it from detaching (stalling) over a wider range of angles of attack, and to control where along the chord the acceleration occurs, which influences the pressure distribution (centre of pressure) and how it changes at different angles of attack.
   
   
   
  
• Supersonic? Way beyond my knowledge, but I think one of the keys is to shape the top surface to avoid the airflow detaching, without the influence of the changing pressure ahead of the wing modifying the airflow.
   
   
  

 

 

You really need to know very little of this to fly an aircraft. You need to know the effect of speed on lift and drag, why the wing stalls and what happens, the effect of surface contamination etc. Newton, Bernoulli etc are really irrelevant to the task of flying an aircraft. They are taught badly, without real understanding, and I think most pilots are confused.

 

* Aerodynamics is complex. I have been interested and learning about it as a hobby for 30+ years. Year 12 physics and chemistry is very helpful but the more I learn, the more I discover that I don't know. These explanations probably also have errors and inaccuracies. I have concluded I have no hope of understanding it properly, unless one day I go back to uni and study it at a tertiary level. Luckily, that level of knowledge isn't required to fly an aircraft.

__________________________________

Practical aerodynamics is not very complex at all..

 

The first sailors learned the principles thousands of years ago. Modern sailors (I have been sailing for over 30 years) need so 'see the flow in order to trim their sails and make them as efficient as possible. Please look at the video from Cambridge at the beginning of this thread and the slides I just posted.

 

Your statement about Newton’s Laws and turning flow is correct and that is my whole point here. I have deliberately not introduced mathematics because this is a conceptual discussion at the level that pilots need to know. Calculus is not necessary but a correct conceptual picture is.

 

Again, it is not that Bernoulli is incorrect, it is that it is explained incorrectly with ETT and ‘Venturi’ theory.

 

Saying that pilots don’t need to understand how a wing works is dangerous. Too many pilots turn back towards the airfield in low airspeed/ engine failure situations and stall/spin in exactly because they do not understand what is happening with their wings..

 

If you want to watch people doing silly things and injuring themselves because they don’t understand the principles of motion watch ‘The Science of Stupid’. It is enlightening.

 

 

[Bruce Tuncks]

There is no contradiction between Newton and Bernoulli. Here's how it works.....

 

The fundamental equations of fluid dynamics are the Navier-Stokes equations, which have been known for 170 years. These were derived by applying Newton's laws to fluid flow, and even if you are good at partial differential vector equations, (which I'm not), you can't solve them.

 

Put in a lot of simplifying assumptions, like how the fluid is incompressible and frictionless and in steady streamline flow and you finally get to Bernoulli, via the Euler equations.

 

Another way of arriving at Bernoulli is through applying conservation of energy, which is inherent in the assumption of frictionless fluid. This is how we derived Bernoulli in high-school back in the good old days. So Bernoulli is really just a statement of the law of conservation of energy.

 

Bernoulli helps explain the pressure distribution around a shaped object, but not a thin plate, in the streamline flow-field of an incompressible and frictionless fluid.

 

There is a good article in the May 2010 magazine by Daffyd Llewellyn where he explains ( without a single differential equation ) how Newton, Bernoulli, and vortex theory are all parts of the same story.

 

I agree that its wrong to say that Bernoulli is sufficient in itself to explain lift. But its also wrong to say Bernoulli is nonsense.

 

.... Bruce

 

 

[turboplanner]

In high power to weight aircraft, and military aircraft a lot of power creates enough force to a virtually flat surface to overcome gravty. The same applies with RC aircraft where the power to weight ratio can be enough to overcome gravity on the prop alone.This is my favourite bit.

 

It shows a stunning lack of understanding.

 

How lift works has nothing to do with how much 'power' you have.

 

100,000LB of thrust at 0 AOA with a flat plate wing will not create ANY lift.

 

Lift only required energy create movement.That energy can come from gravity (a glider) or an engine. A paper plane is the most basic form of a flat wing. It has no thrust (other than your hand) and flies very well.

 

You have completely missed the point that a flat plate is the simplest kind of aerofoil and works by exactly the same laws as any other aerofoil. If turns the air creating a reaction force. A kite does not require any thrust, just the relative motion of the air.

 

I think for the sake of what little credibility you have left, you should retire and ponder what we have discussed. You are just digging a bigger hole…

I'm glad I was able to amuse you. Even the village idiot would understand that 100,000 lb of thrust at zero degrees AoA with a flat plate will not create any lift, and if your mind can't grasp what I was saying without a series of footnotes, I'm happy enough to leave the Bernoulli information to the United States Navy and their $25.00 book.

 

Just a few notes:

 

A sprint car does not have F1 type deflectors, it has quite a deep aerofoil section.

 

This is a recreational flying site where most pilots will NOT be sitting on SC wings - in fact only two or three who are airline pilots would qualify, and a Tobago is a GA aircraft - you are talking to the wrong site.

 

Lastly- you seem not to be able to interpret academic language as you have misinterpreted what the Naval Aviator text is saying.Friction (form drag) is indeed confined to the boundary layer but viscosity is not. If it was the streamlines above the boundary layer would not be affected by the change in velocity (speed and direction) of the boundary layer. Watch the video again or see attached.

What the text is saying is: that in order to study the flow field 'attached to the wing surface' you can ‘neglect’ - not invalidate) the friction in order to make it simpler.

This is what I quoted directly from Aerodynamics for Naval Aviators

 

"All of the aerodynamic forces on a surface are the result of air pressure or air friction.

 

Friction effects are generally confined to a thin layer of air in the immediate vicinity of the surface and friction forces are not predominating forces. Therefore the pressure forces created on an aerodynamic surface can be studied in a simple form which at first neglects the effect of friction and viscosity of the airflow."

 

So my interpretation of that is "neglects", so if you have a problem with that you can argue with:

 

"Aerodynamics for Naval Aviators" NAVWEPS 00-80T-80, Naval Air Systems Command, United States Nav - around $25.00 on Amazon

 

 

[aro]

Fundamentally, I am agreeing with you.

 

A practical understanding of what is happening is not difficult, and helped immensely by videos like the one at the start of the thread. Also videos of tuft testing wings as they stall - widely available now on Youtube - help immensely in visualizing flow and what happens when the wing stalls.

 

However I wouldn't say Bernoulli, Newton etc. are practical aerodynamics - they are theory. And anytime you have to include assumptions you are acknowledging complexity, because the assumption basically says "this bit is too complex to include, but it doesn't make a significant difference in this situation so we can ignore it." It introduces complexity because you have to understand exactly when the assumption holds, and when it does make a difference and you can no longer ignore it e.g. assumptions that ignore compressibility.

 

Saying that pilots don’t need to understand how a wing works is dangerous. Too many pilots turn back towards the airfield in low airspeed/ engine failure situations and stall/spin in exactly because they do not understand what is happening with their wings..

Newton and Bernoulli and all these theories of lift tell us nothing useful about the cause of a stall. Fluid dynamics can probably predict a stall based on viscosity and pressure gradient or something (I don't know) but we learn nothing about that as a pilot.

 

What we need to know is that at some AOA the flow can no longer follow the shape of the wing, and there ia a large reduction in the amount of lift. This is based on AOA, which in turn is based on speed and load factor. It can also be influenced by contaminants on the surface, depending on the airfoil. This is what I meant when I said "why the wing stalls and what happens". This is practical aerodynamics, and I agree that it is not complex.

 

 

[aro]

"The upper flow is faster and from Bernoulli's equation the pressure is lower. The difference in pressure across the airfoil produces the lift. As we have seen in experiment #1, this part of the theory is correct." (NASA's bold) . (I don't think he meant all of the lift, just the top part of the aerofoil).

 

This describes the wings used on Sprint Cars which do such a great job of clamping 850 horsepower cars DOWN on to the track surface, so the geek has some studying to do.

If you understood Aerodynamics for Naval Aviators better you probably wouldn't be arguing with completeaerogeek. They did mean all the lift, not just the top part of the aerofoil. Bernoulli's equation explains the pressure above and below the wing (as long as the assumptions in the theory are valid) - it also tells us that as the flow slows down, the pressure increases. And lift is the difference in pressure between the top and bottom of the wing. It doesn't even matter if the pressure above increases, as long as the pressure below increases more.

 

Sprint car wings are just a high camber wing at a high angle of attack, upside down so they produce downforce rather than lift. Totally different and unrelated to the wing on an airliner.

 

 

[turboplanner]

If you understood Aerodynamics for Naval Aviators better you probably wouldn't be arguing with completeaerogeek. They did mean all the lift, not just the top part of the aerofoil. Bernoulli's equation explains the pressure above and below the wing (as long as the assumptions in the theory are valid) - it also tells us that as the flow slows down, the pressure increases. And lift is the difference in pressure between the top and bottom of the wing. It doesn't even matter if the pressure above increases, as long as the pressure below increases more.

Agree - I fell into the trap of arguing about his comments such as "Bernoulli is irrelevant" and just focusing on the top surface, however I did recommend that people buy the book which goes into much more detail than is practical here, including formulae and much more detailed explanations. And it also covers wings for supersonic aircraft with enough support and calculations to make your eyes spin.

 

Sprint car wings are just a high camber wing at a high angle of attack, upside down so they produce downforce rather than lift. Totally different and unrelated to the wing on an airliner.

Agree - Sprintcar wings have nothing to do with an airliner, and I only introduced it because of this quote from the geek: "Well SC wings were a real change maker. Curved on the bottom and flat on top. Messes with some people's heads!"

 

That's what he said, and a sprint car wing is curved on the bottom and flat on the top, so the resulting force is down, not up.

 

 

[aro]

Agree - Sprintcar wings have nothing to do with an airliner, and I only introduced it because of this quote from the geek: "Well SC wings were a real change maker. Curved on the bottom and flat on top. Messes with some people's heads!"That's what he said, and a sprint car wing is curved on the bottom and flat on the top, so the resulting force is down, not up.

I still don't understand your point here. He says that from what they are taught, people expect that a wing curved on the bottom and flat on the top would produce a down force not lift. And yet that is not the case for SC wings. I'm not sure whether you are agreeing or disagreeing?

 

 

[completeaerogeek]

I'm glad I was able to amuse you. Even the village idiot would understand that 100,000 lb of thrust at zero degrees AoA with a flat plate will not create any lift, and if your mind can't grasp what I was saying without a series of footnotes, I'm happy enough to leave the Bernoulli information to the United States Navy and their $25.00 book.Just a few notes:

 

A sprint car does not have F1 type deflectors, it has quite a deep aerofoil section.

 

This is a recreational flying site where most pilots will NOT be sitting on SC wings - in fact only two or three who are airline pilots would qualify, and a Tobago is a GA aircraft - you are talking to the wrong site.

 

This is what I quoted directly from Aerodynamics for Naval Aviators

 

"All of the aerodynamic forces on a surface are the result of air pressure or air friction.

 

Friction effects are generally confined to a thin layer of air in the immediate vicinity of the surface and friction forces are not predominating forces. Therefore the pressure forces created on an aerodynamic surface can be studied in a simple form which at first neglects the effect of friction and viscosity of the airflow."

 

So my interpretation of that is "neglects", so if you have a problem with that you can argue with:

 

"Aerodynamics for Naval Aviators" NAVWEPS 00-80T-80, Naval Air Systems Command, United States Nav - around $25.00 on Amazon

________________

Remind me not to visit your home village they seem to be missing their idiot. Perhaps its time to go home.

 

I note that you have not addressed the many errors you made in your statements.

 

My flat plate reference was directly aimed at your nonsense about military aircraft.

 

It is fairly apparent that you have no idea what you are talking about and every time you are caught out you ignore your past sins and try to insult me.

 

• You were wrong about the development of SC wings.
   
   
  
• Your point about the sprint cars was moot. F1 cars have spoilers not 'deflectors and they work on exactly the same principle as sprint cars.
   
   
  
• And it is clear despite you blathering that you still don't understand what the Aero book was saying. A bit sad really.
   
   
  
• I didn't say Tobago I said Tomahawk
   
   
  
• The point is that even RA aircraft are using non-traditional aerofoils and to perpetuate nonsense serves no-one.
   
   
  
• Powered hang gliders, parafoils another recreational aircraft use single surface aerofoils which debunk ETT and venturi theory.
   
   
  
• I have never claimed Bernoulli is wrong, just that we don't need it to understand lift (it is after all derived from Newton's 2nd law and incorrect explanations offered to 'prove' Bernoulli leads pilots to have a totally false idea of what is holding them up.
   
   
  

 

 

That Mr Turbo, Was the point of my original post..

 

And it is your assertion that no pilot flying recreationally will every go onto the airlines? And who are the two or three? All modern airliners (and most business jets) use SC wings.

 

Do I have to post the wing profiles so you can get this through your head?

 

If you understand in concept how SC (and all other) aerofoils create lift you will have no problems with any other type.

 

Nevertheless: You are welcome to keep making silly non factual and unsupportable statements if you like. it is quite amusing.

 

 

[completeaerogeek]

I still don't understand your point here. He says that from what they are taught, people expect that a wing curved on the bottom and flat on the top would produce a down force not lift. And yet that is not the case for SC wings. I'm not sure whether you are agreeing or disagreeing?

SC wings produce lift by turning flow. Just like all other wings from from kites to A380s.

 

By using the erroneous 'wing is curved on top so air speeds up to create a low pressure and lift' nonsense everyone just gets confused.

 

The deep convex curve under an SC wing helps push the air forwards and downwards under the wing and this creates a large part of the lift component.

 

Towards the trailing edge there is a reflex curved which redirect the air downwards increasing the turning flow. Outboard of the root twist the wing on top is fairly flat and the 2-4 degrees deck angle in cruising flight couples with the angle of incidence provides all the lift necessary.

 

At lower speeds flaps and slats increase the angle of the turning flow, moving a larger mass of air nwards to compensate for decreasing air speed and energy.

 

 

 

 

[completeaerogeek]

Agree - I fell into the trap of arguing about his comments such as "Bernoulli is irrelevant" and just focusing on the top surface, however I did recommend that people buy the book which goes into much more detail than is practical here, including formulae and much more detailed explanations. And it also covers wings for supersonic aircraft with enough support and calculations to make your eyes spin.

 

Sprint car wings are just a high camber wing at a high angle of attack, upside down so they produce downforce rather than lift. Totally different and unrelated to the wing on an airliner.

Agree - Sprintcar wings have nothing to do with an airliner, and I only introduced it because of this quote from the geek: "Well SC wings were a real change maker. Curved on the bottom and flat on top. Messes with some people's heads!"

 

That's what he said, and a sprint car wing is curved on the bottom and flat on the top, so the resulting force is down, not up.

 

 

Sprint car wings have nothing to do with an airliner? That is priceless!!!!!

 

IS there some alternate physics theory from your Universe you would like to share?

 

 

[aro]

I basically understand what you are saying about the SC wing. I found the stuff about avoiding accelerating air over the top near the speed of sound quite interesting.

 

I just wasn't getting the point of comparing it to a sprint car wing.