Backwash Causes Lift?

Mxsmanic wrote in
:

Le Chaud Lapin writes:

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.

Perhaps you have seen EE from the inside and aerodynamics from the
outside. They may resemble each other far more than you realize.
Remember how well Tesla was received.

2. NASA says it's wrong. From Jim Logajan:
http://www.grc.nasa.gov/WWW/K-12/airplane/bernnew.html

The question, though, is who exactly is "NASA"? The organization
didn't write the text (which, by the way, is an explanation for
schoolkids); a human being did. Is an individual human being as
reliably correct as all of NASA? This is another illustration of the
dangers of credentialism.

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.

Most of the adjustments in wing shape are intended to reduce drag or
raise the critical angle of attack. Otherwise a flat board would
suffice.


Nope. Wrong, fjukktard. A chuck glider 777 is not going to make it to
Tokyo





Bertie

Tina wrote:
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.

I was simply making a point that there are different ways of looking at
the same thing. Much the same with lift and Bernoulli and Newton. Does
the difference in pressure between the top and bottom of the airfoil
cause the downward airflow behind the airfoil, or does the mechanical
deflection of the airflow cause the different in pressure between the
top and bottom of the wing? Inquiring minds want to know? :-)

Matt

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.

What about in the electrolyte inside a battery?

What about in a plasma?

What about in solid electrolytes?


If you are referring to holes http://en.wikipedia.org/wiki/Electron_hole
and electrons in semiconductors http://en.wikipedia.org/wiki/Semiconductor
, where the descriptions of flow of charge through a semiconductor
lattice shows both positive and negative charge flow, in opposite
directions, in the present of an electrical field, the negative charge
being represented by electrons, the positive charge being represented
by holes.

I'm now pretty convinced that you are Mxmaniac and I need to update my
kill file.

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.

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

Ever heard of a proton accelerator?

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

--
Jim Pennino

Remove .spam.sux to reply.

Le Chaud Lapin wrote in
ups.com:

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.

If you are referring to holes
http://en.wikipedia.org/wiki/Electron_hole and electrons in
semiconductors http://en.wikipedia.org/wiki/Semiconductor , where the
descriptions of flow of charge through a semiconductor lattice shows
both positive and negative charge flow, in opposite directions, in the
present of an electrical field, the negative charge being represented
by electrons, the positive charge being represented by holes.

Every book in electrical engineering is likely quite explicit in
telling students up front, (more like forming an agreement with the
students), that the holes are to be modeled as physical particles
because that it is mathematically equivalent to the true phenonmenon,
which is a void moving through the lattice, that, although there are
people who are quite capable of modeling the truth, which is based on
stochastics and energy-band http://en.wikipedia.org/wiki/Energy_band
theory, they will use the one that is simpler since the two models are
functionally equivalent. Note that any professor writing a book
claiming that holes are real particles would probably be barred from
teaching. In the world of electrical engineering, it would be like
saying that the Santa Claus really does exist, knowing that the
professors themselves created the figment of Santa Claus. I cannot
emphasize enough that there is no confusion whatsoever in the minds of
the students about what is actually going on inside the lattice.
There is no doubt in their minds that there are no such thing as
physical particles called holes moving through a lattice. There is no
doubt because professors conscientiously created this fiction, and
tells their students: "We all know that there are no hole
particles...but.." You will notice that the Wikpedia description of
holes uses the word 'conceptual' in the first sentence.

A related concept is something called phonons:
http://en.wikipedia.org/wiki/Phonon These are quantum mechanical
pseudo-particles. Electrical engineers and physicists know that they
do not exist. They know because they made them up, just like the made
up the holes.

There is nothing wrong with doing this. In each case, there is no
untruth being spoken, because the scientists say up front: "We are
about to tell you something that is not really true. Just keep in
mind what the real truth is as we go along, please." This implies
that the EE students know the real truth, which they do, because those
same professors tell them that also. The aerodynamicists say: "We are
about to tell you something that is true.", and they say nothing more,
because they think that what they are about to say is not a
mathematically equivalent model of the truth, but truth itself.

Consider the case where one might do a systems problem to find the
voltage across a capacitorhttp://en.wikipedia.org/wiki/Capacitor, and
end up with something like...

V(t) = 12 * Integral(Delta(t)) + u(t)*e^-3t*e[jwt/(4*pi)]

j is the square root of negative one (-1)
w = angular frequency http://en.wikipedia.org/wiki/Angular_frequency
t = time u(t) is Heaviside step function
http://en.wikipedia.org/wiki/Unit_step_function Delta(t) is the
Dirac-delta function http://en.wikipedia.org/wiki/Dirac_delta)

This voltage contains complex numbers sitting n an exponential. It
also contains a phenomenon that occurs so quick that is is
mathematically impossible to observe in time, yet its effect during
that brief moment is infinite. This is ridiculous. We know with
certainty that no such things exist in real-life. But that's ok,
because we made these things. Electrical engineers looking at this
will know immediately what the truth is, what the math represents.
What is odd is that one eventually reachs a point where no uneasiness
at all comes from moving between the real and the unreal. They are,
in an abstract sense, in separable.

Futhermore, concerning the point you made, if the above voltage V(t)
is positive, then by the formula for charge on a capacitor, Q=CV,
since C, the capacitance, is [ahemm....always positive...please, if
you are a EE reading this, please don't start up with me about general
impedance converters ], the the charge is possitive, but we just
noted in the semiconductor example above that one does not find
positive charge running around in circuits because the are constrained
to the nuclei of atoms http://en.wikipedia.org/wiki/Atomic_nucleus
with their neutron buddies. This does not bother electrical engineers
because they see the formula and immediately see the image of what is
going on, the truth of physics as it occurs. Note that, if the
formula claims that there is positive charge on one plate of the
capacitor, there really is no positive charge "on the plate" so to
speak, but a depletion of negative charge, which is mathematically
eqivalent model of truth, just as there is no such thing as square-
root of negative number in real life, but if you use Euler's Formula
http://en.wikipedia.org/wiki/Euler's_formula, a Taylor expansion of
the formula about t http://en.wikipedia.org/wiki/Taylor_expansion, you
will see that the V(t) comes out to the nice sine waves that you would
see on an oscilloscopehttp://en.wikipedia.org/wiki/Oscilloscope .

Contrast this with what the aerodynamicists are doing. They are not
issuinig disclaimers saying, "this is not really what is happening, we
all know that, but let us pretend to make the math simpler for now".
They claim what they are illustrating *is* the truth.


Yes, they are, they're just no ttelling you because you aren't designing
airplanes, fjukkwit.

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. Even if aerodynamicists (is that even a
word) were so inept at physics that could not even calculate F=ma,
after so many iterations, they would still be able to make highly
refined airfoils simply because nature provides feedback to help one
distinguish between good designs and bad designs.

However, I must point out something I noted yesterday, that if you
have theory as well as the practice, the correct theory, there might
be opportunity to experience and entiely new realm of order and
efficiency.

I re-read the chapter on fluid mechanics in my physics book last night
and it says exactly what that NASA article refutes. Naturally, I was
bit perturbed - this physics book is same one used by some very good
universities. It also read in it a near verbatim explanation of
downwash as an example of Newton's law at work, that I found in the
Jeppesen book, the same explanation with is rigorously refuted by
NASA. I remember reading this chapter over and over a long time ago,
and "not getting it", and now I realize that it's because it is most
likely wrong.

In any case, there is something to be said for re-examining the
theory. There might be a bit of opportunity here.

I *think* I understand the physics behind reduced pressure above a
moving, appropriately shaped airfoil. *If* my suspicions are correct,
then it should be possible to make an entirely new type of aircraft,
where the mechanims to keep the aircraft flying are entirely different
from what they are today. I won't say too much now. I know no one
will consider it anyway. I'll just start fiddling, albeit slowly,
with my copy of SolidWorks that is coming in the mail soon.

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

-Le Chaud Lapin-



You're an idiot


Bertie

"Dan Luke" wrote in news:13gercm9vnp7160
@news.supernews.com:


"Bertie the Bunyip" wrote:


The physicists I know worry about confirming their calculations by
observation. I don't know who MX is referring to.


The little "Famous physicists " pics he had on his jammies.

Haw!

You're on a hot streak, Bertie.


Thanks, a good k00king always brings out the best!


Bertie

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."

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....", Barry Schiff, and the person who wrote the
article at NASA, will say, "No. We do not agree with what you just
said."

-Le Chaud Lapin-

Mxsmanic wrote in
:

Matt Whiting writes:

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 absolute truth is unknown, and the real proof of wizardry is the
ability to say "I don't know."




And the proof of your idiocy is that you can actualy say that with a
presumably straight face.