Airplane Pilot's As Physicists

On Oct 11, 10:10 am, Nomen Nescio wrote:

Just a "heads up".
"Mxsmanic" and "Le Chaud Lapin" are the same person.

And they're both idiots.

You rate him/them far to highly

wrote:
On Oct 10, 7:46 am, Dudley Henriques wrote:
Bertie the Bunyip wrote:
"CWatters" wrote in
:
"Mxsmanic" wrote in message
...
The essential feature of an airfoil is that it twists the flow of
air as
it
passes (or as the airfoil passes through still air, which is
equivalent,
and
that's how it works in airplanes). The air is accelerated downward,
and
this
engenders an equal and opposite force that is lift.
Nope. That wouldn't explain how wing sections for tailless planes
work. The sections for those curve up towards the trailing edge. The
leading edge produces lift but the trailing edge produces a _downward_
force to counter the pitching moment. Example section...
http://www.desktopaero.com/appliedae...mages/image13_
43.
gif
Good point.
The porblem with this guy is (and it's just one guy with a handful of
sockpuppets) is that he ses some discrepencies in how bernoulli is
explained and has concluded that it must be incorrect since there is
"disagreement amongst the experts"
A good analogy here would be the eeedjit creationists who grasp at the
straws presented by the minor scuffles occuring within the evolutionary
sciences.
Bertie
This is exactly how I see this as well. This character and his puppets
are playing out a conversation with themselves (one person) designed to
capitalize on the few simple misconceptions concerning Bernoulli that
are common knowledge among the professional aviation community and have
been "corrected" years ago.
Unfortunately for this forum, there are still a few old textbooks
hanging around out there reflecting these misconceptions. This, coupled
with the fact that there are individual pilots out here (from the GA
community mostly) who apparently lack the formal physics knowledge to
take on someone whose sole intent is to discredit them by cleverly using
the remaining confusion in the community concerning Bernoulli against them.
The REAL rub in this situation is that the idiot doing this, from what I
have seen in his posting, has very little knowledge HIMSELF about the
lift issue and is totally wrong in critical areas of his argument.
It's an unfortunate situation designed by a person who seems to pleasure
himself by what he's doing.
Personally I wouldn't give this idiot the time of day. His understanding
of Bernoulli is much worse than those with whom he has engaged. Those
who are on to him he avoids, only taking glancing shots at them knowing
he won't be answered directly.
It's a shame really....but what the hell, it's Usenet!!
:-)))

--
Dudley Henriques

I haven't minded taking the bait. The process has
pointed out many good websites we can use in instruction, and has
forced a review of some basic principles. Got to find the silver
lining, right?

Dan


A good visual tool I've used as an example through the years is a
cylinder. Stationary with no circulation on a cylinder in a freestream
you have a 0 AOA stagnation point leading and trailing edge with equal
streamlines. No Bernoulli; no Newton. no lift.
Now spin the cylinder (same as increasing AOA on an airfoil...simple
Magnus effect)and you lower both stagnation points front and back as
circulation becomes a factor. You now have Bernoulli top and bottom and
up wash and down wash created simultaneously on the cylinder; you also
now have lift!
An airfoil works the same way as it rotates through angle of attack.
Actually, a barn door will work the same way as well :-))

There are differences of course in how symmetrical and cambered airfoils
work as far as the center of pressure and moment arms work on the wings
vs angle of attack and zero lift but basically using a cylinder then
rotating it demonstrates simply that if lift is being created, both
Bernoulli and Newton are existing at the same time and either can be
used to explain how a net lift force is created.
The rest of it is all peripheral data and usually confuses both people
as well as the airport cat as they get lost in what causes what how what
causes lift.

--
Dudley Henriques

wrote
Denny, this newsgroup is pretty effectively moderated by Bertie. The
Dudley man does a good job too.
\
Sadly, it has deteriorated to the current state.

People used to have real discussions about flying, instead of the constant
discord.

I long for the return of discussions where an idiot does not pervert every
thread, and all of the people that left, return.
--
Jim in NC

"Jim Logajan" wrote in message
.. .
"ABLE_1" wrote:
http://uk.youtube.com/watch?v=KCcZyW-6-5o

Enjoy!!!

Here's something that flies which doesn't rely on Bernoulli's theorem:

http://uk.youtube.com/watch?v=1T2gg4zpyuo


....except when it's trying to climb fast, or turn. :-)

"CWatters" wrote in message
...

"Jim Logajan" wrote in message
.. .
"ABLE_1" wrote:
http://uk.youtube.com/watch?v=KCcZyW-6-5o

Enjoy!!!

Here's something that flies which doesn't rely on Bernoulli's theorem:

http://uk.youtube.com/watch?v=1T2gg4zpyuo


...except when it's trying to climb fast, or turn. :-)



Oh and for the props.

I think that the shape of the wing simply allows for a greater range of
angles of attack. A sheet of plywood would provide lift, but only at a very
precise and small angle of attack. The airfoil shape allows the wing to
provide lift through a much larger range of angles of attack.

JMO.

mike
"Gatt" wrote in message
...

"Bertie the Bunyip" wrote in message
...
Mxsmanic wrote in
:

Le Chaud Lapin writes:

Even though this (new) thread is not about what causes a wing to lift,
I just wanted to say for the record that I agree with this answer,
that it is both AoA and curvature of the wing.

It's just AOA.

Nope.

There goes my Lapin = MX theory. Apologies to Chaud are probably in
order. (I probably apologize?)

-c

Jim Logajan wrote:

Uncle Al wrote:
2) Bernoulli's law is strictly a 2-D analysis.

Are you sure? I ask because I know the application of Bernoulli's theorem
to airfoils is typically restricted to 2-D and wondering if that is what
you meant. Otherwise there doesn't appear to be any dimensional assumption
in the theory itself or its derivation. Here's one typical presentation of
Bernoulli's theorem:

"In the steady motion of an inviscid fluid the quantity

p/rho + K

is constant along a streamline, where p is the pressure, rho is the density
and K is the energy per unit mass of fluid."

And the definition of streamline also appears void of dimensional
restriction:

"A line drawn in the fluid so that its tangent at each point is in the
direction of the fluid velocity at that point is called a streamline."

Both quotes from "Theoretical Aerodynamics" by L. M. Milne-Thomson.

So unless I'm mistaken (and I could be) it appears that Bernoulli's
theorem:
1) Applies to compressible or incompressible fluids.
2) Does not necessarily apply to viscous fluid flows.
3) Does not necessarily apply to turbulent flow (it's not "steady motion".)
4) Does not itself define the flow streamlines.
5) Is not restricted to 1 or 2 dimensional analysis.

3-D wings are more than Bernoulli's law. If they weren't they
wouldn't vastly benefit from shaped distal winglets to control vortex
shedding. Adding small drag surfaces at the wingtips normal to the
wings' surfaces does not have beneficial - much less hugely beneficial
- effects in 2-D analysis. In the real world airlines madly scrambled
to add winglets to improve fuel economy.

Look at the ratio of surface areas, wing and its winglet. The real
world benefits are wholly disproportional to area ratio. It is a
matter of leverage. A tiny tweaking of vortices rolling off distal
wing ends creates major energy control.

--
Uncle Al
http://www.mazepath.com/uncleal/
(Toxic URL! Unsafe for children and most mammals)
http://www.mazepath.com/uncleal/lajos.htm#a2

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

I haven't minded taking the bait. The process has pointed
out many good websites we can use in instruction, and has
forced a review of some basic principles. Got to find the silver lining,
right?

Right.

Nothing wrong with a little discussion.

Why did you post "True Understanding Or Monkey Mode" about the same thing in
rec.aviation.piloting. Are you accusing pilots of being monkeys?

If so, do you expect to be treated with some sort of respect by people who
actually read aviation textbooks and fly planes? By the way, how's that
EB-6 training going?

-c

"Gig 601XL Builder" wrDOTgiaconaATsuddenlink.net wrote in message
...

He's a sockpuppet. A creation.

Who do you think he is a sock puppet for, MX?

Yes. His content, character and tone are strikingly similar to what MX was
posting around the time everybody was at Oshkosh. Lots of nonsense about
AOA, camber, downwash, etc.

-c

"Morgans" wrote in message
...

Sadly, it has deteriorated to the current state.

People used to have real discussions about flying, instead of the constant
discord.

Actually, I'm enjoying the tangental stuff that people like Dudley are
posting. Actual physics. Even if somebody appears to be trolling, it's
useful to hear experts articulate what we all pretty much know, plus I've
gotten at least two useful book recommendations out of the thread.

Maybe the OP is just a foil for the rest of us to talk about aerodynamics.
Works for me.

-c