On 28 Okt, 05:39, Dave <n...@home.com> wrote:
If you will be satisfied with empirical evidence, stick your hand out
the window of the car while going 50-60 MPH. Experiment with
different
angles of attack. You will no doubt experienceliftwhen your hand has
a positive angle of attack. Poor man's wind tunnel - but illustrates
that just about anything relatively flat will fly
given enough speed and a positive angle of attack.

David Johnson

The problem is probably, that Bertie does have a car, so the simple
experiment is not possible for him.

He might find a bus, where he can open the window and try.

The risk is that he does not understand the physical effects on his
hand.

Since he does not understand how to see the vertical airflow from the
wings at AOA in this picture, he has a big problem:

http://www.efluids.com/efluids/gallery/gallery_pages/Morris_3.jsp

Look again, fjukkwit.

On 27 Okt, 17:10, Bertie the Bunyip <S...@rt.1> wrote:
jon <newb...@algonet.se> wrote
innews:1193496270.442636.260090@d55g2000hs
g.googlegroups.com:





On 26 Okt, 08:24, Bertie the Bunyip <S...@rt.1> wrote:
jon <newb...@algonet.se> wrote
innews:1193336318.130848.213230@i13g2000pr
f.googlegroups.com:

On 17 Okt, 01:48, Le Chaud Lapin <jaibudu...@gmail.com> wrote:
On Oct 16, 3:31 pm, Thomas <thomas.s...@gmail.com> wrote:

On 16 Oct, 19:41, Jim Logajan <Jam...@Lugoj.com> wrote:

Thomas <thomas.s...@gmail.com> wrote:
You may want to check out my web pages
http://www.physicsmyths.org.uk/bernoulli.htmand

http://www.physicsmyths.org.uk/drag.htmforacloserexaminatio
n of
the physics behind the aerodynamicliftand drag.

You might want to actually _include_Bernoulli'stheorem
somewhere in y
our
pages. You talk
aboutBernoulli'sequation,Bernoulli'sprinciple,
and
Bernoulli'slaw. And yet none of them are actually presented.
Are you
saying they all the same or all different? Why not use the
terminolog
y used
by the professionals and stick with "Bernoulli'stheorem"?
How about including references to relevant texts on your
pages? It's not like s
erious
texts and lab experiments haven't been done on the subject
for a zill
ion
years. It helps to show you know what you're talking about
by showing you've first read the professional literature on
the subject and done
your
own relevant research.

You might also want to redraw your figures so they include
vertical l
abeled
arrows. Then present the assumptions and math needed to
show your wor
k and
why you think the vertical magnitudes sum to zero. Just
saying they d
o, or
they only yield a torque, isn't good enough. It is more
useful to _sh
ow_ -
not pontificate and hand-wave.

P.S. Chapter section 40-3 in volume 2 of Feynman's Lectures
on Physic
s is
as good a place as any to start.

Bernoulli'stheorem is not a fundamental physical law and thus
not
required to understand the principle behind the
aerodynamiclift. And its misinterpretation and misapplication
quite evidently leads to incorrect physical conclusions, like
the claim that a moving gas would inherently have a lower
static pressure than a stationary one. The net flow velocity
of a gas has per se nothing to do with the static pressure.

I so agree. The amout of hand-waving that goes on when
(presumably technically-inclined) individuals invokeBernoulliis
perplexing. Oddly, my college physics book is almost as guilty
- after chapters and chapters of Newtonian mechanics that are
quite clear, they seem to imply just that.

As a thought experiment, consider a large tank containing gas
with a pipe attached to it which leads into a vacuum space.
Assume first this pipe is closed at the end; then the flow
velocity in the pipe is zero because the molecules heading
outwards will be reflected at the end and reverse their
velocity (assume for simplicity that the molecules do not
collide with each other but only with the walls of the pipe
and the tank). If one now opens the pipe, the only thing that
changes is that the molecules heading outwards will not be
reflected anymore at the end but simply carry on heading into
the vacuum space (with the corresponding loss of molecules
being replaced from the large tank). So we now have a net
flow velocity within the pipe without that either the density
nor the speed of the molecules has changed in any way. This
means that the pressure exerted on the inside wall of the
pipe is unchanged despite the fact that we now have a net
flow velocity within it. SoBernoulli'stheorem would quite
evidently give a wrong result here.

Hmmm...technically, someone could argue that, in the vicinity
of the exit hole of the tank, there would be resulting decrease
in pressure, which would be true.

The misapplication, I think, results from too much hand-waving
and not being very specific about what pressure decreases over
what. A venturi apparutus, for example, very clearly
demonstrates a drop in pressure, and that drop is real, but the
points chosen to measure the pressure in the apparutus is very
specific.

-Le Chaud Lapin-- Dölj citerad text -

- Visa citerad text -- Dölj citerad text -

- Visa citerad text -

The venturi pipe is mostly misunderstood. To get through the
narrow section, the fluid must be pressed against the convergent
part with a higher pressure. The Coanda effect forces the fluid
to follow the walls in the divergent part.

All early speed sensors in 1920 used only the divergent part of
the venturi pipe.

Look att Bleriot and other planes. Look at Piper Colt 1953 model
with its backpart venturi. The front convergent part was not
needed.

Piper Colt 1953 model?

Unh unh. First flew in 1960 you fjukkwit.

Backpart Venturi?

Bwawhahwhahwhahwhahwhahwha!

Changing the airflow direction over and under the wing, creates
the local pressure gradients + or - .

Nope.

Bertie

- Dölj citerad text -

- Visa citerad text -- Dölj citerad text -

- Visa citerad text -

The backpart of a venturi is sitting also on the Piper Colt 1960-64
models, like it does on the 1953 TriPacer of the same family.

They didn't make the colt from 60-64, fjukkwit.

One does not need the convergent entrance part, to measure the
airspeed.

One doesn't need a venturi to measure airspeed either, fjukkktard.

OH, BTW, we met real life once. the other pilots in the room nearly
pissed their pants laughing about you in the bar afterwards.

Why don't you tell he bois and gurls here what you do for a living?

Bertie- Dölj citerad text -

- Visa citerad text -

Since you are such a superexpert Bertie, Bombardier needs your help to
fix the landinggear problem!

Now 9 incidents happened with failed landinggear!

We can not block more runways with Q400 anymore and we need your help
Bertie, since you know everything in the

aviation world.

And you still believe the aircrafts are sucked up in the sky, like
Apollo went to the moon?

jon <newb...@algonet.se> wrote innews:1193496270.442636.260090@d55g2000hsg.googlegroups.com:





On 26 Okt, 08:24, Bertie the Bunyip <S...@rt.1> wrote:
jon <newb...@algonet.se> wrote
innews:1193336318.130848.213230@i13g2000pr
f.googlegroups.com:

On 17 Okt, 01:48, Le Chaud Lapin <jaibudu...@gmail.com> wrote:
On Oct 16, 3:31 pm, Thomas <thomas.s...@gmail.com> wrote:

On 16 Oct, 19:41, Jim Logajan <Jam...@Lugoj.com> wrote:

Thomas <thomas.s...@gmail.com> wrote:
You may want to check out my web pages
http://www.physicsmyths.org.uk/bernoulli.htmand
http://www.physicsmyths.org.uk/drag.htmforacloserexamination
of
the physics behind the aerodynamicliftand drag.

You might want to actually _include_Bernoulli'stheorem
somewhere in y
our
pages. You talk aboutBernoulli'sequation,Bernoulli'sprinciple,
and
Bernoulli'slaw. And yet none of them are actually presented.
Are you
saying they all the same or all different? Why not use the
terminolog
y used
by the professionals and stick with "Bernoulli'stheorem"? How
about including references to relevant texts on your pages?
It's not like s
erious
texts and lab experiments haven't been done on the subject for
a zill
ion
years. It helps to show you know what you're talking about by
showing you've first read the professional literature on the
subject and done
your
own relevant research.

You might also want to redraw your figures so they include
vertical l
abeled
arrows. Then present the assumptions and math needed to show
your wor
k and
why you think the vertical magnitudes sum to zero. Just saying
they d
o, or
they only yield a torque, isn't good enough. It is more useful
to _sh
ow_ -
not pontificate and hand-wave.

P.S. Chapter section 40-3 in volume 2 of Feynman's Lectures on
Physic
s is
as good a place as any to start.

Bernoulli'stheorem is not a fundamental physical law and thus not
required to understand the principle behind the aerodynamiclift.
And its misinterpretation and misapplication quite evidently
leads to incorrect physical conclusions, like the claim that a
moving gas would inherently have a lower static pressure than a
stationary one. The net flow velocity of a gas has per se
nothing to do with the static pressure.

I so agree. The amout of hand-waving that goes on when
(presumably technically-inclined) individuals invokeBernoulliis
perplexing. Oddly, my college physics book is almost as guilty -
after chapters and chapters of Newtonian mechanics that are quite
clear, they seem to imply just that.

As a thought experiment, consider a large tank containing gas
with a pipe attached to it which leads into a vacuum space.
Assume first this pipe is closed at the end; then the flow
velocity in the pipe is zero because the molecules heading
outwards will be reflected at the end and reverse their velocity
(assume for simplicity that the molecules do not collide with
each other but only with the walls of the pipe and the tank). If
one now opens the pipe, the only thing that changes is that the
molecules heading outwards will not be reflected anymore at the
end but simply carry on heading into the vacuum space (with the
corresponding loss of molecules being replaced from the large
tank). So we now have a net flow velocity within the pipe
without that either the density nor the speed of the molecules
has changed in any way. This means that the pressure exerted on
the inside wall of the pipe is unchanged despite the fact that
we now have a net flow velocity within it. SoBernoulli'stheorem
would quite evidently give a wrong result here.

Hmmm...technically, someone could argue that, in the vicinity of
the exit hole of the tank, there would be resulting decrease in
pressure, which would be true.

The misapplication, I think, results from too much hand-waving and
not being very specific about what pressure decreases over what. A
venturi apparutus, for example, very clearly demonstrates a drop
in pressure, and that drop is real, but the points chosen to
measure the pressure in the apparutus is very specific.

-Le Chaud Lapin-- Dölj citerad text -

- Visa citerad text -- Dölj citerad text -

- Visa citerad text -

The venturi pipe is mostly misunderstood. To get through the
narrow section, the fluid must be pressed against the convergent
part with a higher pressure. The Coanda effect forces the fluid to
follow the walls in the divergent part.

All early speed sensors in 1920 used only the divergent part of the
venturi pipe.

Look att Bleriot and other planes. Look at Piper Colt 1953 model
with its backpart venturi. The front convergent part was not
needed.

Piper Colt 1953 model?

Unh unh. First flew in 1960 you fjukkwit.

Backpart Venturi?

Bwawhahwhahwhahwhahwhahwha!

Changing the airflow direction over and under the wing, creates the
local pressure gradients + or - .

Nope.

Bertie

- Dölj citerad text -

- Visa citerad text -- Dölj citerad text -

- Visa citerad text -

The backpart of a venturi is sitting also on the Piper Colt 1960-64
models, like it does on the 1953 TriPacer of the same family.

They didn't make the colt from 60-64, fjukkwit.

One does not need the convergent entrance part, to measure the
airspeed.

One doesn't need a venturi to measure airspeed either, fjukkktard.

OH, BTW, we met real life once. the other pilots in the room nearly
pissed their pants laughing about you in the bar afterwards.

Why don't you tell he bois and gurls here what you do for a living?

Bertie- Dölj citerad text -

- Visa citerad text -

If you will be satisfied with empirical evidence, stick your hand out
the window of the car while going 50-60 MPH. Experiment with different
angles of attack. You will no doubt experienceliftwhen your hand has
a positive angle of attack. Poor man's wind tunnel - but illustrates
that just about anything relatively flat will fly
given enough speed and a positive angle of attack.

David Johnson

If you will be satisfied with empirical evidence, stick your hand out
the window of the car while going 50-60 MPH. Experiment with different
angles of attack. You will no doubt experience lift when your hand has
a positive angle of attack. Poor man's wind tunnel - but illustrates
that just about anything relatively flat will fly
given enough speed and a positive angle of attack.

"Dave" <nf6f@home.com> wrote in message
news:1193546340.331819.72770@d55g2000hsg.googlegroups.com...
If you will be satisfied with empirical evidence, stick your hand out
the window of the car while going 50-60 MPH. Experiment with
different angles of attack. You will no doubt experience lift when
your hand has a positive angle of attack. Poor man's wind tunnel -
but illustrates that just about anything relatively flat will fly
given enough speed and a positive angle of attack.

That's why wings have camber. 'Cause they don't need 'em.

Bertie's a shill for the Alcoa Camber Conspiracy. ...they've sold
more metal by convincing every successful aircraft designer and
manufacturer in the history of aviation that upper camber is
necessary, when all they need are two simple deflection plates.

Fortunately, the wizards at sci.physics have busted the conspiracy and
we all see now how the designers of all aircraft were grievously
wrong.