Why Airplanes Fly - Voids Above A Planar Sheet

On Oct 6, 1:59 pm, Jim Logajan wrote:
As far as I know, Machado, Schiff, and Gann are experts in piloting,
not
aerodynamics. There is very large difference in having a degree in
"Aviation Science" and Aerodynamics. The former seems to typically
include only one course in aerodynamics and an associates degree can be
obtained in only two years. Since no calculus is required, the
aerodynamics presented is likely to be qualitative and not quantitative.
An aerodynamics engineering degree, on the other hand, is at least four
years and a couple years of aerodynamic courses. Calculus is required and
is intended to impart enough knowledge to a student so they could design
aircraft.

Hmm....do you think then that it is reasonable to expect a person with
Ph.D. in aviation science (that's what I read somewhere) to know what
causes lift on an airplane, without math?

But what is in my Jeppensen book and
what Barry Schiff wrote is wrong.

It could also be considered incomplete, rather than outright wrong.

In this case, it is outright wrong. I have the book here with me. I
can retype the entire section, the copy and paste from the NASA link
that you gave earlier, and it will be plainly obvious that two
descriptions are polar opposites.

I don't agree with your approach to how you handled the contradictions
you encountered. If you can handle the math and physics, I think you
should move on to that level, not "put on the brakes." The problem is not
one of piloting, but rather understanding the physics and aerodynamics,
so I'm not sure why you chose to post to a piloting group. I would
suggest you post a query asking for authoritative texts and material to
one or more of these groups:

By "putting on the brakes", I mean that I stopped reading books that
seem to have erroneous explanations of what causes lift.

sci.physics
sci.mech.fluids
sci.physics.computational.fluid-dynamics
sci.aeronautics

I thought about the fluids group, but I thought this group might be a
bit open-minded. Not to say that the fluid dynamicists are not open-
minded, but..after all, unless Jeppesen has fluid-dynamicists on
staff, it is they who started promulgating wrong information in the
first place. Also, if there are scientists lurking in the room who
are thorougly convinced that the NASA article, for example, is
wrong...there might be a tendency to ask me questions like:

1. "Do you have any experience in fluid dynamics?"
2. "Do you understand more than high school math?"
3. "Are you really trained as an engineeer?"

I thought I could avoid all of that by presenting a qualitative
exposition, without the numbers first, to an audience that is almost
guaranteed to have visceral experiences with the descriptions, then,
if there was something more to discuss, move on to rigorous
exploration. I barely got past the double-sheet-of-paper experiment.

I do not the fault the experts. They have authored much material on the
subject. But it's a complex subject - just as complex as quantum
mechanics, for example. But some people insist on seeking easy to
undertand or otherwise "intuitive" explanations for systems where
multiple constraints are operating simultaneously. So when explanations
are reduced to comprehensible bits something has to give. I'm not sure
why you appear shocked by this.

Hmm...I guess that's fair enough. Bernoulli, IMO, is at play above the
wing, but as the NASA article pointed out, it has nothing to do with
the description given by Jeppensen or even an online aero-astro text I
was reading yesterday. I guess it is possible that, a long time ago,
during a conference, someone mentioned Bernoulli and above-the-wing in
same sentence, and people started printing untruth. So maybe the
truth has always been known. But so far, the vast majority of
textbooks I see have printed the opposite of what that NASA article is
saying.

That downwash-Newton-thing, is simply inexcusable. Newton's law of
reciprocity is not complicated at all. Someone who understands this
law could look at the the description and see that it is incorrect
while understanding essentially zero about aerodynamics.

I just realized that when I take my KT, there is a good chance that
there will be a question that asks about the theory of lift. If that
NASA article is correct, there will be a small white lie for the
points.

Also, since you are the one who posted the NASA link, I have two
questions:

1. Do you understand thoroughly NASA's explanation why they think the
other authors are wrong?
2. Do you agree with them?

-Le Chaud Lapin-

Le Chaud Lapin wrote in
ups.com:

On Oct 6, 1:59 pm, Jim Logajan wrote:
As far as I know, Machado, Schiff, and Gann are experts in piloting,
not
aerodynamics. There is very large difference in having a degree in
"Aviation Science" and Aerodynamics. The former seems to typically
include only one course in aerodynamics and an associates degree can
be obtained in only two years. Since no calculus is required, the
aerodynamics presented is likely to be qualitative and not
quantitative. An aerodynamics engineering degree, on the other hand,
is at least four years and a couple years of aerodynamic courses.
Calculus is required and is intended to impart enough knowledge to a
student so they could design aircraft.

Hmm....do you think then that it is reasonable to expect a person with
Ph.D. in aviation science (that's what I read somewhere) to know what
causes lift on an airplane, without math?

But what is in my Jeppensen book and
what Barry Schiff wrote is wrong.

It could also be considered incomplete, rather than outright wrong.

In this case, it is outright wrong. I have the book here with me. I
can retype the entire section, the copy and paste from the NASA link
that you gave earlier, and it will be plainly obvious that two
descriptions are polar opposites.

I don't agree with your approach to how you handled the
contradictions you encountered. If you can handle the math and
physics, I think you should move on to that level, not "put on the
brakes." The problem is not one of piloting, but rather understanding
the physics and aerodynamics, so I'm not sure why you chose to post
to a piloting group. I would suggest you post a query asking for
authoritative texts and material to one or more of these groups:

By "putting on the brakes", I mean that I stopped reading books that
seem to have erroneous explanations of what causes lift.

sci.physics
sci.mech.fluids
sci.physics.computational.fluid-dynamics
sci.aeronautics

I thought about the fluids group, but I thought this group might be a
bit open-minded. Not to say that the fluid dynamicists are not open-
minded, but..after all, unless Jeppesen has fluid-dynamicists on
staff, it is they who started promulgating wrong information in the
first place. Also, if there are scientists lurking in the room who
are thorougly convinced that the NASA article, for example, is
wrong...there might be a tendency to ask me questions like:

1. "Do you have any experience in fluid dynamics?"
2. "Do you understand more than high school math?"
3. "Are you really trained as an engineeer?"

I thought I could avoid all of that by presenting a qualitative
exposition, without the numbers first, to an audience that is almost
guaranteed to have visceral experiences with the descriptions, then,
if there was something more to discuss, move on to rigorous
exploration. I barely got past the double-sheet-of-paper experiment.

I do not the fault the experts. They have authored much material on
the subject. But it's a complex subject - just as complex as quantum
mechanics, for example. But some people insist on seeking easy to
undertand or otherwise "intuitive" explanations for systems where
multiple constraints are operating simultaneously. So when
explanations are reduced to comprehensible bits something has to
give. I'm not sure why you appear shocked by this.

Hmm...I guess that's fair enough. Bernoulli, IMO, is at play above the
wing, but as the NASA article pointed out, it has nothing to do with
the description given by Jeppensen or even an online aero-astro text I
was reading yesterday. I guess it is possible that, a long time ago,
during a conference, someone mentioned Bernoulli and above-the-wing in
same sentence, and people started printing untruth. So maybe the
truth has always been known. But so far, the vast majority of
textbooks I see have printed the opposite of what that NASA article is
saying.

That downwash-Newton-thing, is simply inexcusable. Newton's law of
reciprocity is not complicated at all. Someone who understands this
law could look at the the description and see that it is incorrect
while understanding essentially zero about aerodynamics.

I just realized that when I take my KT, there is a good chance that
there will be a question that asks about the theory of lift. If that
NASA article is correct, there will be a small white lie for the
points.

Also, since you are the one who posted the NASA link, I have two
questions:

1. Do you understand thoroughly NASA's explanation why they think the
other authors are wrong?
2. Do you agree with them?



You don't know enough to decide that either is wrong.

You're an idiot, anthony

Bertie

Le Chaud Lapin wrote:
Hmm....do you think then that it is reasonable to expect a person with
Ph.D. in aviation science (that's what I read somewhere) to know what
causes lift on an airplane, without math?

1) Rod Machado does not appear to have a Ph.D. He claims many things and
if he had one I'm sure he would say so. He's not shy about his
accomplishments. Here is the bio on his web site:
http://www.rodmachado.com/Bio/Bio.html

2) If you want to predict the approximate lift, drag, torques, pressures,
temperatures, and such on an airplane then one requires math. Math is
required to do anything usefully predictive. Since all physics models,
whether mathematical or intuitive, are merely approximations of physical
reality, they all (to different extents) produce "wrong" results. But I'm
not like you and would say they produce progressively less useful
results. For the purposes of piloting I see no value in a precise
explanation of lift - it's right up there with knowing Maxwell's
equations or field effect transister theory before one can be allowed to
use a radio.

In this case, it is outright wrong. I have the book here with me. I
can retype the entire section, the copy and paste from the NASA link
that you gave earlier, and it will be plainly obvious that two
descriptions are polar opposites.

I don't think that would accomplish anything useful.

Find the contact information for the authors of the book and send them
the NASA link and politely point out that their text appears to
contradict the NASA explanation and ask them if they could either
reconcile the two explanations or if they could consider updating any
future edition to address the issue.

Also, since you are the one who posted the NASA link, I have two
questions:

1. Do you understand thoroughly NASA's explanation why they think the
other authors are wrong?

First, their articles are hardly comprehensive on all the ways the
explanations for lift can be wrong. That said, they pointed out that
empirical evidence disputes the "equal time" theory and computations
using the "stone skipping" theory don't match observations either. I've
been aware of the limitations of those explanations years before I
located those NASA pages.

2. Do you agree with them?

You mean with NASA? Well, I agree with the content of those two web pages
at least. Actually a lot of the material in that series of pages is
nicely done.

"Le Chaud Lapin" wrote in message
ups.com...

I guess it is possible that, a long time ago,
during a conference, someone mentioned Bernoulli and above-the-wing in
same sentence, and people started printing untruth. So maybe the
truth has always been known.

The truth has been known since at least early August when I revealed to
MXManiac that upper camber is a conspiracy by Alcoa to sell more aluminum.
Bernoulli was probably a stockholder.

-c