Backwash Causes Lift?

Tina wrote in news:1191678837.514394.4670
@r29g2000hsg.googlegroups.com:

Matt, come on, you're better than that. You have to know what you're
talking about re current flow is simply accepting one convention or
another. In either case (using a plus or a minus sign consistantly
when writing loop equations for example) the calculations and
observations match fairly well.

The hand waving about lift is equally funny: people are attaching
names to various theories, but the reality is the physics used in the
analysis of lift work well enough to predict performance. The 'wise
fools' will wave their hands and argue, those knowing what they are
doing will design airplanes.



Yep

Bertie

Le Chaud Lapin wrote in
oups.com:

On Oct 6, 8:53 am, Tina wrote:
The hand waving about lift is equally funny: people are attaching
names to various theories, but the reality is the physics used in the
analysis of lift work well enough to predict performance. The 'wise
fools' will wave their hands and argue, those knowing what they are
doing will design airplanes.

This I definitely agree with.


No you don't



I plan eventually to make a small-scale model. Hopefully, someday, I
might find someone involved in aerodynamics/flight to help make a
prototype.


You couldn't make a succesful papaer dart.

Bertie

Le Chaud Lapin wrote in
oups.com:

On Oct 6, 12:45 pm, wrote:
Le Chaud Lapin wrote:

On Oct 6, 6:38 am, Matt Whiting wrote:
Really? Many books still can't agree on the definition of
current. Some say it is the movement of electrons and some say it
is the movement of positive charge and some say it us both.
Which is the absolute truth, Mr. Wizard?
The truth is that the electrons move, not the protons.

You've fallen into the trap you are complaining about and providing
a simplistic answer that isn't true under all circumstances.

Uh...no. The difference, as I pointed out with great redunancy in my
post, is that, in one case, there are two situations:

1. The truth, which the observers know.
2. The untruth, which the obsevers concoct to make the math simpler,
all the while keeping in mind what the truth is.

This is what happens with semiconductors.

In the other case, there is only one situation:

1. What the observers think is the truth.

In this latter case in aerodynamics, the observers do not say, "We all
know that this is not what is really happening..". Instead, they say,
"This is what's happening."

I can think of no mechanism to move protons in a solid, but they
move quite well in a vacuum.

Yes, I know. When I was tutoring electrodynamics, I used the problem
that I am sure you are familiar with, a proton, entering a uniform
magnetic field, and one must find the radius of its circular motion
based on the mass of the proton, the magnetic field intensity, etc.
This problem is so common, I decided to use a proton instead of an
electron to try to catch students who were cheating by simply copying
problems from previous years. The answer given by cheaters would have
the right radius but the wrong direction.

Ever heard of a proton accelerator?

Yes, in fact, I had it as a disclaimer in my original post, just as I
had a disclaimer about a capacitor not being negative. [Note I said
that capacitors have positive capacitance, which is true, until you
start implementing virtual capacitors using general impedance
converters, which can make them negative, but then they are not real
capacitors, etc.] I took out counterexample about proton accelerators
because Wikipedia did not have an immediate link for the exact phrase
"proton accelerator", and the related links were bordering on quantum
physics, and I certainly don't want to open up a can of worms about
quantum physics in this group.

A current flow in a proton accelerator is a current flow of protons.

Sure. But no one ever disputed that. Matt was implying that electrical
engineers/physicist cannot agree on what is actually going on, which
is not true. Most physicists who work with proton accelerators are
quite aware that that there is a proton moving under the influence of
the Lorentz force in an accelerator. No particle physicist ever
claims otherwise. Also, if you ask a bunch of electrical engineers,
"Does everyone that every know that there really is no such thing as a
hole, that it is in fact massive numbers of protons, entering an
exiting the energy band according to a stochastic model?" They would
say, "Yes, yes, we know! Now get on with your talk about these non-
existent holes."

Aerodynamics, today, is different. If you ask a bunch of aeronautical
engineers, "Does everyone know that the lift is due to the air on top
traveling faster than the air beneath, thus invoking Bernoulli's
Principle..yada yada....",


You are a liar,. You've never asked anyone at Nasa anything.

Bertie

Mxsmanic wrote in
:

Le Chaud Lapin writes:

On Oct 6, 6:38 am, Matt Whiting wrote:
Really? Many books still can't agree on the definition of current.
Some say it is the movement of electrons and some say it is the
movement of positive charge and some say it us both. Which is the
absolute truth, Mr. Wizard?

The truth is that the electrons move, not the protons.

He said "movement of positive charge," not "movement of protons."


Yeh, right sockpuppet boi


Bertie

On Oct 5, 6:27 pm, Mxsmanic wrote:

The angle of attack is the angle between the forward stagnation point and the
trailing stagnation point. The points of intersection of the chord line with
the airfoil surface are static, but the stagnation points can change, altering
the angle of attack.

This has never been an accepted definition of angle of attack and
your creation of it has no credibility. You just create even more
confusion in your mind and in the minds of innocent truth-seekers
here.

If the angle of attack is not positive, there is no lift. You cannot have
lift at negative angles of attack because that is not symmetric.

So you don't believe NASA or NACA or anyone else that finds
lift at negative AOAs on some airfoils?

Dan

On Oct 6, 12:14 am, Le Chaud Lapin wrote:
On Oct 5, 6:32 pm, wrote:

People are going to yell and boo me for saying this, but after taking
a nice long ride tonight on my motorcyle tonight, I thought the
venturi/Bernoulli thing through, and I am 95% certain that that is not
the reason the pressure is lower. In fact, I could probably provide an
experiment showing you a situation where air is moving considerably
faster on top than it is on the bottom, with much higher presure on
the top. What is ironic is that Bernoulli would still be right, but
the interpretation of Bernoulli would fall apart.

You keep talking about designing this experiment. Nothing
was ever accomplished with a lot of empty talk. When are you going to
start proving your theories? If you come up with something truly
revolutionary, we will all bow and scrape and tell our friends that we
had mistakenly defied a true master.


Newton said that for every action there's an equal and
opposite reaction. If you look at the diagrams of airflow here,http://www.av8n.com/how/htm/airfoils.html
scrolling down to Figure 3.2, you'll see that there's upwash ahead of
the wing as well as downwash behind it. the upwash is generated by the
approaching low pressure area above the wing. As the wing passes, the
upwash is converted to downwash; if this isn't Newton at work, I don't
know what is. Newton would be just another dead guy.

Newton did say that. And I looked at that diagram very carefully.
[Thanks for link] The upwash is not casued by an approaching low
pressure. The upwash is caused by a gradient in pressure, going from
high pressure at the leading ede, to low pressure, right above and
slightly-back of the wing, due to rarefication of the wing in motion.

And that's not an effect of the approaching low pressure? In
any subsonic flow, the effect of any disturbance of the air travels
outward at the speed of sound. An approaching wing will affect air
molecule movement well ahead of it.

The area above the rarefication is normal atmosphere that has a
propensity to move toward the lower-pressure, rarefied air. The
combination of that normal atmosphere air, combine with the high
velocity of the molecules from the leading edge of the wing, results
in the flow paths (streams) that you see. I haven't looked yet, but I
imagine that there are aerodynamicists, all over the world, who, if
not for appreciation of the hypothesis I am proposing here, have at
least figured this out empircally, and are fretting day and night
trying to find the optimal shape of the leading edge of the wing.
They have two conflicting objectives:

1. Make the shape in such a way so as to minimize drag.
2. Make the shape in such a way so as to increase pressure to impart
high velocity to air molecules moving up/backwards.

I'll be the first to admit that i don't have the capacity to do so at
this moment, but imagine that that one shape of the leading edge is
not appropriate for all speeds of the aircraft.

Finally, two true statements: 1. You don't have the capacity, and 2.
The leading edge you see is not appropriate for all speeds of
aircraft. There are MANY different leading edges out there. I imagine
you haven't seen them.


For a given set of
context variables like density, temperature, pressure, angle-of-
attack, airspeed, what-the-plane-was-doing-20-milliseconds-ago,
turbulences...wind, etc...there is an optimal shape for that leading
edge, depending on what you are trying to do. It would be quite wild
if someone were to design a wing that could morph, dynamically by
control of a computer, into an instaneously-optimal shape.

As if the engineers haven't been working on these wings for
years already. I have an article on my desk in front of me about
morphing helicopter blades to deal with retreating-blade stall. You
didn't really think you had a new idea, did you?
We already have variable-geometry wings. The fighter's swing-
wings, the airliner's triple-slotted flaps and its leading-edge slats
and flaps, on and on. All varying the airfoil for different speed
regimes and maneuvers. The problem with your instantaneous change is
one of maintaining structural integrity and strength and resistant to
flutter while keeping the weight low enough that it will fly. Maybe
you can solve that for us.


I believe it should be possible to explain a venturi tube, Bernoulli's
principle, and a decent part of why a wing has lift, in about 2-3
pages of written text, with pictures, using no formulas, not even
grade-school mathematics.

Commonly done in many texts. You just haven't read them yet.

If a student wants to argue that the physics as presented are
all wrong he should do extensive research and publish a book on the
subject, not argue with pilots who have been trusting their soft pink
bodies to Bernoulli and Newton for decades.

I definitely agree a paper should be written, and there should be an
element of rigor, obviously lacking in my posts.

Obviously.

There is a flow of goofy ideas through your head,
increasing in velocity, so that a vacuum is forming there.

Dan

On Oct 6, 8:26 pm, Bertie the Bunyip wrote:
Le Chaud Lapin wrote oups.com:



On Oct 5, 6:32 pm, wrote:
It's familiar because there are many out there who don't
understand or don't agree with the textbooks. Even among experts
there's disagreement. Every so often one of them makes an issue of
it. It's quite normal, especially if they don't use the Google Groups
Search function first to see what the previous arguments have been on
the subject on a particular newsgroup.

I'd like to first note something since I am newly exposed to this
field:

In electrical engineering, we have our own set of fundamental
principles. The "terminal" set of primitives governing electronics
(electrostatics and electrodynamics) is Maxwells Equations
http://en.wikipedia.org/wiki/Maxwell_equation. [Ironically, during
his lifetime, Maxwell was also someone who was a leading expert on
aerodynamics. The notions of gradients, the Laplacian, and scalar
potentials have strong parallels in both fields.] In EE, we have out
own myths, like power lines causing brain cancer, but when they arise,
the experts work hard to show indisputable evidence, verifiable,
rigorous evidence to the contrary, to nip the non-sense in the bud.
We do still have areas of disputes, like what causes shot noise in
circuits [http://en.wikipedia.org/wiki/Shot_noise], but on the bread-
and-butter basics, you won't find a college-leve textbook speaking
untruth. So naturally I am extremely surprised to see this happening
in aerodynamics. You are, after all, the rocket scientists.

It annoys some of us because the same arguments are put forth
repeatedly and we can't figure out why some don't get it. But it's no
different than my classroom, in which every new batch of students
brings the same misunderstandings and doubts and arguments. We were
young once, too, and didn't believe much of what our teachers were
trying to tell us.

Oh, I certainly don't believe what I wrote in the Jeppensen book. I
don't believe what the 3 CFI's told me recently. I don't believe what
my friends friend, the pilot, told me three years ago. And though I
would be highly honored if I could meet him, I don't believe what Rod
Machado, whom I think we would all agree is not exactly dumb nor a bad
teacher, nor ignorant in the field, wrote. I don't believe it for two
reasons:

1. It's obviously wrong if you read and interpret correctly what
Bernoulli wrote.
2. NASA says it's wrong. From Jim Logajan:
http://www.grc.nasa.gov/WWW/K-12/airplane/bernnew.html

Bernoulli said that moving air has a lower pressure than
static air. The air over the top of the wing is moving considerably
faster than that underneath, so it has lower pressure.

People are going to yell and boo me for saying this, but after taking
a nice long ride tonight on my motorcyle tonight, I thought the
venturi/Bernoulli thing through, and I am 95% certain that that is not
the reason the pressure is lower. In fact, I could probably provide an
experiment showing you a situation where air is moving considerably
faster on top than it is on the bottom, with much higher presure on
the top. What is ironic is that Bernoulli would still be right, but
the interpretation of Bernoulli would fall apart.

It's not
rarefaction; it's the increase in dynamic pressure (velocity) that
subtracts from static pressure, the same phenomenon that makes a
turbine engine work so well.

Not to nit-pick, but dynamic pressure is p(t), where t is time, and
velocity is d/dt R(t), where R is position vector, two totally
different things.

Newton said that for every action there's an equal and
opposite reaction. If you look at the diagrams of airflow
here,http://www.av8n.com/how/htm/airfoils.htmlscrolling down to
Figure 3.2, you'll see that there's upwash ahead of the wing as well
as downwash behind it. the upwash is generated by the approaching low
pressure area above the wing. As the wing passes, the upwash is
converted to downwash; if this isn't Newton at work, I don't know
what is. Newton would be just another dead guy.

Newton did say that. And I looked at that diagram very carefully.
[Thanks for link] The upwash is not casued by an approaching low
pressure. The upwash is caused by a gradient in pressure, going from
high pressure at the leading ede, to low pressure, right above and
slightly-back of the wing, due to rarefication of the wing in motion.
The area above the rarefication is normal atmosphere that has a
propensity to move toward the lower-pressure, rarefied air. The
combination of that normal atmosphere air, combine with the high
velocity of the molecules from the leading edge of the wing, results
in the flow paths (streams) that you see. I haven't looked yet, but I
imagine that there are aerodynamicists, all over the world, who, if
not for appreciation of the hypothesis I am proposing here, have at
least figured this out empircally, and are fretting day and night
trying to find the optimal shape of the leading edge of the wing.
They have two conflicting objectives:

1. Make the shape in such a way so as to minimize drag.
2. Make the shape in such a way so as to increase pressure to impart
high velocity to air molecules moving up/backwards.

I'll be the first to admit that i don't have the capacity to do so at
this moment, but imagine that that one shape of the leading edge is
not appropriate for all speeds of the aircraft. For a given set of
context variables like density, temperature, pressure, angle-of-
attack, airspeed, what-the-plane-was-doing-20-milliseconds-ago,
turbulences...wind, etc...there is an optimal shape for that leading
edge, depending on what you are trying to do. It would be quite wild
if someone were to design a wing that could morph, dynamically by
control of a computer, into an instaneously-optimal shape.

For the average PPL or CPL this should be sufficient. It's
true
enough, even if it doesn't give the detail that the physicist would
like. As I said, most pilots have other careers and interests and
they find that Newton and Bernoulli jibe with what they experience in
the air, so they're satisfied. Making textbooks thicker or filling
them with competing theories does nothing but confuse these people.

I believe it should be possible to explain a venturi tube, Bernoulli's
principle, and a decent part of why a wing has lift, in about 2-3
pages of written text, with pictures, using no formulas, not even
grade-school mathematics.

If a student wants to argue that the physics as presented are
all wrong he should do extensive research and publish a book on the
subject, not argue with pilots who have been trusting their soft pink
bodies to Bernoulli and Newton for decades.

I definitely agree a paper should be written, and there should be an
element of rigor, obviously lacking in my posts.

However, I honestly think pilot's have been trusting neither Bernoulli
nor Newton. They are dead. But they each left a legacy, which,
according to the NASA links, have been misinterpreted and abused by
countless theoritsts and educators in this field. So one could say
that the pilots have been trusting these theorists and educators, but
perhaps not even that is the case. I think what Ron hinted at is most-
likely the case, that there is a phenomenon that would allow even a
Neanderthal to achieve technical advancement:

The Neanderthal starts with a contraption that works, and through much
trial-and-error, finds better and better rendentions of that same
contraption. Eventually, he will have something that works so well,
that the question of "Why" would hardly need be asked. Naturally,
theorists will tag along and try to explain with rigorous scientific
principles what he has accomplished with only raw will of spirit, but
the theory does not necessarily have to be right or complete get the
thing in the air. Of course, the Wright Brothers were high-minded
individuals, but I think you get the point.

One might ask, "Well if that is the case, then what is the point of
nit-picking with theory?"

It is because a theory that correctly explains observed phenomenon
generally opens up an entirely new world of order and efficiency.

-Le Chaud Lapin-

Wanna make a bet about how long it takes you to get your licence?

Let's have a pool!

I got never!

90 hours to solo

george wrote in
ps.com:

On Oct 6, 8:26 pm, Bertie the Bunyip wrote:
Le Chaud Lapin wrote
oups.com:



On Oct 5, 6:32 pm, wrote:
It's familiar because there are many out there who don't
understand or don't agree with the textbooks. Even among experts
there's disagreement. Every so often one of them makes an issue of
it. It's quite normal, especially if they don't use the Google
Groups Search function first to see what the previous arguments
have been on the subject on a particular newsgroup.

I'd like to first note something since I am newly exposed to this
field:

In electrical engineering, we have our own set of fundamental
principles. The "terminal" set of primitives governing electronics
(electrostatics and electrodynamics) is Maxwells Equations
http://en.wikipedia.org/wiki/Maxwell_equation. [Ironically, during
his lifetime, Maxwell was also someone who was a leading expert on
aerodynamics. The notions of gradients, the Laplacian, and scalar
potentials have strong parallels in both fields.] In EE, we have
out own myths, like power lines causing brain cancer, but when they
arise, the experts work hard to show indisputable evidence,
verifiable, rigorous evidence to the contrary, to nip the non-sense
in the bud. We do still have areas of disputes, like what causes
shot noise in circuits [http://en.wikipedia.org/wiki/Shot_noise],
but on the bread- and-butter basics, you won't find a college-leve
textbook speaking untruth. So naturally I am extremely surprised to
see this happening in aerodynamics. You are, after all, the rocket
scientists.

It annoys some of us because the same arguments are put
forth
repeatedly and we can't figure out why some don't get it. But it's
no different than my classroom, in which every new batch of
students brings the same misunderstandings and doubts and
arguments. We were young once, too, and didn't believe much of
what our teachers were trying to tell us.

Oh, I certainly don't believe what I wrote in the Jeppensen book.
I don't believe what the 3 CFI's told me recently. I don't believe
what my friends friend, the pilot, told me three years ago. And
though I would be highly honored if I could meet him, I don't
believe what Rod Machado, whom I think we would all agree is not
exactly dumb nor a bad teacher, nor ignorant in the field, wrote.
I don't believe it for two reasons:

1. It's obviously wrong if you read and interpret correctly what
Bernoulli wrote.
2. NASA says it's wrong. From Jim Logajan:
http://www.grc.nasa.gov/WWW/K-12/airplane/bernnew.html

Bernoulli said that moving air has a lower pressure than
static air. The air over the top of the wing is moving
considerably faster than that underneath, so it has lower
pressure.

People are going to yell and boo me for saying this, but after
taking a nice long ride tonight on my motorcyle tonight, I thought
the venturi/Bernoulli thing through, and I am 95% certain that that
is not the reason the pressure is lower. In fact, I could probably
provide an experiment showing you a situation where air is moving
considerably faster on top than it is on the bottom, with much
higher presure on the top. What is ironic is that Bernoulli would
still be right, but the interpretation of Bernoulli would fall
apart.

It's not
rarefaction; it's the increase in dynamic pressure (velocity) that
subtracts from static pressure, the same phenomenon that makes a
turbine engine work so well.

Not to nit-pick, but dynamic pressure is p(t), where t is time, and
velocity is d/dt R(t), where R is position vector, two totally
different things.

Newton said that for every action there's an equal and
opposite reaction. If you look at the diagrams of airflow
here,http://www.av8n.com/how/htm/airfoils.htmlscrolling down to
Figure 3.2, you'll see that there's upwash ahead of the wing as
well as downwash behind it. the upwash is generated by the
approaching low pressure area above the wing. As the wing passes,
the upwash is converted to downwash; if this isn't Newton at work,
I don't know what is. Newton would be just another dead guy.

Newton did say that. And I looked at that diagram very carefully.
[Thanks for link] The upwash is not casued by an approaching low
pressure. The upwash is caused by a gradient in pressure, going
from high pressure at the leading ede, to low pressure, right above
and slightly-back of the wing, due to rarefication of the wing in
motion. The area above the rarefication is normal atmosphere that
has a propensity to move toward the lower-pressure, rarefied air.
The combination of that normal atmosphere air, combine with the
high velocity of the molecules from the leading edge of the wing,
results in the flow paths (streams) that you see. I haven't looked
yet, but I imagine that there are aerodynamicists, all over the
world, who, if not for appreciation of the hypothesis I am
proposing here, have at least figured this out empircally, and are
fretting day and night trying to find the optimal shape of the
leading edge of the wing. They have two conflicting objectives:

1. Make the shape in such a way so as to minimize drag.
2. Make the shape in such a way so as to increase pressure to
impart high velocity to air molecules moving up/backwards.

I'll be the first to admit that i don't have the capacity to do so
at this moment, but imagine that that one shape of the leading edge
is not appropriate for all speeds of the aircraft. For a given set
of context variables like density, temperature, pressure, angle-of-
attack, airspeed, what-the-plane-was-doing-20-milliseconds-ago,
turbulences...wind, etc...there is an optimal shape for that
leading edge, depending on what you are trying to do. It would be
quite wild if someone were to design a wing that could morph,
dynamically by control of a computer, into an instaneously-optimal
shape.

For the average PPL or CPL this should be sufficient. It's
true
enough, even if it doesn't give the detail that the physicist
would like. As I said, most pilots have other careers and
interests and they find that Newton and Bernoulli jibe with what
they experience in the air, so they're satisfied. Making textbooks
thicker or filling them with competing theories does nothing but
confuse these people.

I believe it should be possible to explain a venturi tube,
Bernoulli's principle, and a decent part of why a wing has lift, in
about 2-3 pages of written text, with pictures, using no formulas,
not even grade-school mathematics.

If a student wants to argue that the physics as presented
are
all wrong he should do extensive research and publish a book on
the subject, not argue with pilots who have been trusting their
soft pink bodies to Bernoulli and Newton for decades.

I definitely agree a paper should be written, and there should be
an element of rigor, obviously lacking in my posts.

However, I honestly think pilot's have been trusting neither
Bernoulli nor Newton. They are dead. But they each left a legacy,
which, according to the NASA links, have been misinterpreted and
abused by countless theoritsts and educators in this field. So one
could say that the pilots have been trusting these theorists and
educators, but perhaps not even that is the case. I think what Ron
hinted at is most- likely the case, that there is a phenomenon that
would allow even a Neanderthal to achieve technical advancement:

The Neanderthal starts with a contraption that works, and through
much trial-and-error, finds better and better rendentions of that
same contraption. Eventually, he will have something that works so
well, that the question of "Why" would hardly need be asked.
Naturally, theorists will tag along and try to explain with
rigorous scientific principles what he has accomplished with only
raw will of spirit, but the theory does not necessarily have to be
right or complete get the thing in the air. Of course, the Wright
Brothers were high-minded individuals, but I think you get the
point.

One might ask, "Well if that is the case, then what is the point of
nit-picking with theory?"

It is because a theory that correctly explains observed phenomenon
generally opens up an entirely new world of order and efficiency.

-Le Chaud Lapin-

Wanna make a bet about how long it takes you to get your licence?

Let's have a pool!

I got never!

90 hours to solo



A control-line model


Bertie

wrote in
oups.com:

On Oct 6, 12:14 am, Le Chaud Lapin wrote:
On Oct 5, 6:32 pm, wrote:

People are going to yell and boo me for saying this, but after taking
a nice long ride tonight on my motorcyle tonight, I thought the
venturi/Bernoulli thing through, and I am 95% certain that that is
not the reason the pressure is lower. In fact, I could probably
provide an experiment showing you a situation where air is moving
considerably faster on top than it is on the bottom, with much higher
presure on the top. What is ironic is that Bernoulli would still be
right, but the interpretation of Bernoulli would fall apart.

You keep talking about designing this experiment. Nothing
was ever accomplished with a lot of empty talk. When are you going to
start proving your theories? If you come up with something truly
revolutionary, we will all bow and scrape and tell our friends that we
had mistakenly defied a true master.


Newton said that for every action there's an equal and
opposite reaction. If you look at the diagrams of airflow
here,http://www.av8n.com/how/htm/airfoils.html scrolling down to
Figure 3.2, you'll see that there's upwash ahead of the wing as
well as downwash behind it. the upwash is generated by the
approaching low pressure area above the wing. As the wing passes,
the upwash is converted to downwash; if this isn't Newton at work,
I don't know what is. Newton would be just another dead guy.

Newton did say that. And I looked at that diagram very carefully.
[Thanks for link] The upwash is not casued by an approaching low
pressure. The upwash is caused by a gradient in pressure, going from
high pressure at the leading ede, to low pressure, right above and
slightly-back of the wing, due to rarefication of the wing in motion.

And that's not an effect of the approaching low pressure? In
any subsonic flow, the effect of any disturbance of the air travels
outward at the speed of sound. An approaching wing will affect air
molecule movement well ahead of it.

The area above the rarefication is normal atmosphere that has a
propensity to move toward the lower-pressure, rarefied air. The
combination of that normal atmosphere air, combine with the high
velocity of the molecules from the leading edge of the wing, results
in the flow paths (streams) that you see. I haven't looked yet, but
I imagine that there are aerodynamicists, all over the world, who, if
not for appreciation of the hypothesis I am proposing here, have at
least figured this out empircally, and are fretting day and night
trying to find the optimal shape of the leading edge of the wing.
They have two conflicting objectives:

1. Make the shape in such a way so as to minimize drag.
2. Make the shape in such a way so as to increase pressure to impart
high velocity to air molecules moving up/backwards.

I'll be the first to admit that i don't have the capacity to do so at
this moment, but imagine that that one shape of the leading edge is
not appropriate for all speeds of the aircraft.

Finally, two true statements: 1. You don't have the capacity, and 2.
The leading edge you see is not appropriate for all speeds of
aircraft. There are MANY different leading edges out there. I imagine
you haven't seen them.


For a given set of
context variables like density, temperature, pressure, angle-of-
attack, airspeed, what-the-plane-was-doing-20-milliseconds-ago,
turbulences...wind, etc...there is an optimal shape for that leading
edge, depending on what you are trying to do. It would be quite wild
if someone were to design a wing that could morph, dynamically by
control of a computer, into an instaneously-optimal shape.

As if the engineers haven't been working on these wings for
years already. I have an article on my desk in front of me about
morphing helicopter blades to deal with retreating-blade stall. You
didn't really think you had a new idea, did you?
We already have variable-geometry wings. The fighter's swing-
wings, the airliner's triple-slotted flaps and its leading-edge slats
and flaps, on and on. All varying the airfoil for different speed
regimes and maneuvers. The problem with your instantaneous change is
one of maintaining structural integrity and strength and resistant to
flutter while keeping the weight low enough that it will fly. Maybe
you can solve that for us.


I believe it should be possible to explain a venturi tube,
Bernoulli's principle, and a decent part of why a wing has lift, in
about 2-3 pages of written text, with pictures, using no formulas,
not even grade-school mathematics.

Commonly done in many texts. You just haven't read them yet.

If a student wants to argue that the physics as presented
are
all wrong he should do extensive research and publish a book on the
subject, not argue with pilots who have been trusting their soft
pink bodies to Bernoulli and Newton for decades.

I definitely agree a paper should be written, and there should be an
element of rigor, obviously lacking in my posts.

Obviously.

There is a flow of goofy ideas through your head,
increasing in velocity, so that a vacuum is forming there.


So, ironically, he has probven Bernoulli after all.

Bertie

On Oct 6, 2:09 pm, wrote:
I believe it should be possible to explain a venturi tube, Bernoulli's
principle, and a decent part of why a wing has lift, in about 2-3
pages of written text, with pictures, using no formulas, not even
grade-school mathematics.

Commonly done in many texts. You just haven't read them yet.

Which texts are those?

I have read some texts:

1. Jeppesen got it wrong.
2. Rod Machado got it wrong.
3. That link that with the funny color lines that was posted in this
thread got it wrong.
4. If you do search in Google for "Bernoulli" + "faster" + wing +
lift, you will see 1000's of pages that got it wrong.

Plus I watched 3 CFI's at my ground school, the one I paid money to
teach me the theory of flying, get it wrong at the whiteboard.

And of course, if the NASA paper is true, then there are even people
in this group who got it wrong.

Until 3 days ago, the number of people who had gotten (partially)
right was 1. The number of stories I had heard from people who got it
wrong was probably about 60-70.

After reading the link that Jim Logajan posted, the number of people
who are saying it's one way is 2. The number of people who are saying
it is the exact opposite is still 60-70.

Which textbooks would you believe if you had read 1 saying one thing,
and more than 10 others saying the exact opposite?

-Le Chaud Lapin-