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-