Airplane Pilot's As Physicists

Mxsmanic wrote:
Le Chaud Lapin writes:

If you read carefully, the premise of what they are saying is that, if
you have, for example, a sealed jar with air in it, you are permitted
to consider the air on the _inside_ of the jar, pushing up on the lid
as contributing to a force to lift the jar off the ground, but you are
not allowed to consider the air on the _inside_ of the jar, pushing
down on the jar un the upper surface of the bottom of the jar.

The atmosphere is not a sealed jar. The source of air pressure in the
atmosphere is gravity, not confinement and kinetic energy.

I feel as though I am in the presence of
genius.....

Jim Stewart wrote in news:4-
:

Mxsmanic wrote:
Le Chaud Lapin writes:

If you read carefully, the premise of what they are saying is that, if
you have, for example, a sealed jar with air in it, you are permitted
to consider the air on the _inside_ of the jar, pushing up on the lid
as contributing to a force to lift the jar off the ground, but you are
not allowed to consider the air on the _inside_ of the jar, pushing
down on the jar un the upper surface of the bottom of the jar.

The atmosphere is not a sealed jar. The source of air pressure in the
atmosphere is gravity, not confinement and kinetic energy.

I feel as though I am in the presence of
genius.....


Take a tums, it'll get better


Bertie

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

If you read carefully, the premise of what they are saying is that, if
you have, for example, a sealed jar with air in it, you are permitted
to consider the air on the _inside_ of the jar,

WTF is he talking about? Nobody said anything about air -inside- of a wing.

-c

On Oct 9, 4:35 pm, "Gatt" wrote:
"Le Chaud Lapin" wrote in oglegroups.com...

If you read carefully, the premise of what they are saying is that, if
you have, for example, a sealed jar with air in it, you are permitted
to consider the air on the _inside_ of the jar,

WTF is he talking about? Nobody said anything about air -inside- of a wing.

On Oct 9, 1:00 pm, Phil wrote:
Le Chaud Lapin wrote:
If you
don't like the concept that the top of the wing is being sucked upward
by that lower pressure

It is not a matter of whether I like it or not. It is something that
simply does not happen. There is no sucking force.

I think you mis-understood me here. When I say the air below the line
is pressing upward, I am not referring to the air pressing upward on
the bottom of the wing. I am referring to the air _inside_ the wing
pressing upward on the underside of the top surface of the wing. The
air above the wing top surface has lower than normal pressure. The
air inside the wing has normal pressure. So it presses upward on the
top surface of the wing. This is lift generated by the top surface of
the wing.

Phil

-Le Chaud Lapin-

On Oct 9, 4:30 pm, Le Chaud Lapin wrote:
On Oct 9, 3:22 pm, Randy Poe wrote:



On Oct 9, 4:08 pm, Le Chaud Lapin wrote:

Hi All,

There is a long discussion ongoing in rec.aviation.piloting about what
causes lift on a plane.

Heh. I know the argument. I think it's broken out here (sci.physics)
many times.

(a) It's the Bernoulli effect due to the shape of the
wing cross-section, the way we were all taught as kids.

(b) No, it's just the angle of attack.

I'm no expert, but I heard enough in similar arguments here
to convince me that the angle-of-attack people are right and
the shape of the wing has more to do with controlling
turbulence.

There are people in the pilot's group, who think that lift on a wing
is analyzed as such:

1. There is air on outside of top of wing that is pushing down, but
reduced because of aerodynamics.
2. The *inside* of the wing contains air pushing up against the
underside of top of wing .

Er... that's a new one. OK, I haven't heard this argument
then.

3. Let us ignore that the same air inside the wing pushes down on the
overside of bottom part of wing.
4. The difference in pressure against the underside of the top wing on
the inside of wing and top of wing on outside, is what gives plane
lift.

You can consider that last just a definition of lift. You
won't get lift unless the upward forces are stronger than
then downward forces.

Note that they ignore the pressure inside the wing that pushes
downward on the wing.

A wing doesn't need to be hollow to fly.

I am trying to convince them that, if there is air on the inside of
the wing, it pushes against all sides of the inside of the wing,
including both top underside and bottom overside, and thereby
nullifying any effect it would have on the wing. Lift is caused by a
difference in pressure between the underside of the bottom of the
wing, and the overside of the top of the wing.

Thanks Randy,

But before we talk about what causes lift on the plane, we should
clear up the basic physics 1st. Note that what I have described above
has nothing to do with airplanes really.

If you read carefully, the premise of what they are saying is that, if
you have, for example, a sealed jar with air in it, you are permitted
to consider the air on the _inside_ of the jar, pushing up on the lid
as contributing to a force to lift the jar off the ground, but you are
not allowed to consider the air on the _inside_ of the jar, pushing
down on the jar un the upper surface of the bottom of the jar.

Sure, there's air pressure inside a sealed jar, but:

(1) Sealed jars sitting on tables don't spontaneously start
flying, and

(2) Conservation of momentum (for every action there's
an equal and opposite reaction) says that you can't push
up from the inside. You'll create a counter force pushing
down.

(3) Solid things fly in wind also.

- Randy

Randy Poe wrote in
ps.com:

On Oct 9, 4:30 pm, Le Chaud Lapin wrote:
On Oct 9, 3:22 pm, Randy Poe wrote:



On Oct 9, 4:08 pm, Le Chaud Lapin wrote:

Hi All,

There is a long discussion ongoing in rec.aviation.piloting about
what causes lift on a plane.

Heh. I know the argument. I think it's broken out here
(sci.physics) many times.

(a) It's the Bernoulli effect due to the shape of the
wing cross-section, the way we were all taught as kids.

(b) No, it's just the angle of attack.

I'm no expert, but I heard enough in similar arguments here
to convince me that the angle-of-attack people are right and
the shape of the wing has more to do with controlling
turbulence.

There are people in the pilot's group, who think that lift on a
wing is analyzed as such:

1. There is air on outside of top of wing that is pushing down,
but reduced because of aerodynamics.
2. The *inside* of the wing contains air pushing up against the
underside of top of wing .

Er... that's a new one. OK, I haven't heard this argument
then.

3. Let us ignore that the same air inside the wing pushes down on
the overside of bottom part of wing.
4. The difference in pressure against the underside of the top
wing on the inside of wing and top of wing on outside, is what
gives plane lift.

You can consider that last just a definition of lift. You
won't get lift unless the upward forces are stronger than
then downward forces.

Note that they ignore the pressure inside the wing that pushes
downward on the wing.

A wing doesn't need to be hollow to fly.

I am trying to convince them that, if there is air on the inside
of the wing, it pushes against all sides of the inside of the
wing, including both top underside and bottom overside, and
thereby nullifying any effect it would have on the wing. Lift is
caused by a difference in pressure between the underside of the
bottom of the wing, and the overside of the top of the wing.

Thanks Randy,

But before we talk about what causes lift on the plane, we should
clear up the basic physics 1st. Note that what I have described
above has nothing to do with airplanes really.

If you read carefully, the premise of what they are saying is that,
if you have, for example, a sealed jar with air in it, you are
permitted to consider the air on the _inside_ of the jar, pushing up
on the lid as contributing to a force to lift the jar off the ground,
but you are not allowed to consider the air on the _inside_ of the
jar, pushing down on the jar un the upper surface of the bottom of
the jar.

Sure, there's air pressure inside a sealed jar, but:

(1) Sealed jars sitting on tables don't spontaneously start
flying, and

(2) Conservation of momentum (for every action there's
an equal and opposite reaction) says that you can't push
up from the inside. You'll create a counter force pushing
down.

(3) Solid things fly in wind also.


You also need a bull**** detector.

I can do that and the sarcasm detector as a deal for you if you like.


Bertie

On Oct 9, 6:15 pm, Randy Poe wrote:
(2) Conservation of momentum (for every action there's
an equal and opposite reaction) says that you can't push
up from the inside. You'll create a counter force pushing
down.

Finally, someone speaks reason.

Now all we need to do is see that the jar might as well be a the
volume of a wing, and the same principle applies.

Not possible to have air on inside of wing pushing up against
underside of top of wing without having same said air pushing downward
on overside of bottom part of wing.

-Le Chaud Lapin-

Le Chaud Lapin wrote in news:1191974445.830019.13730
@57g2000hsv.googlegroups.com:

On Oct 9, 6:15 pm, Randy Poe wrote:
(2) Conservation of momentum (for every action there's
an equal and opposite reaction) says that you can't push
up from the inside. You'll create a counter force pushing
down.

Finally, someone speaks reason.

Now all we need to do is see that the jar might as well be a the
volume of a wing, and the same principle applies.

Not possible to have air on inside of wing pushing up against
underside of top of wing without having same said air pushing downward
on overside of bottom part of wing.



Good god.

Bertie

On Oct 9, 6:00 pm, Le Chaud Lapin wrote:
On Oct 9, 6:15 pm, Randy Poe wrote:

(2) Conservation of momentum (for every action there's
an equal and opposite reaction) says that you can't push
up from the inside. You'll create a counter force pushing
down.

Finally, someone speaks reason.

Now all we need to do is see that the jar might as well be a the
volume of a wing, and the same principle applies.

Not possible to have air on inside of wing pushing up against
underside of top of wing without having same said air pushing downward
on overside of bottom part of wing.

-Le Chaud Lapin-

Shoot. And here we used to help the 150 off the ground on a hot
day by pushing up on the ceiling, and if the wind was calm we'd blow
on the windshield, too. Are you saying we were wasting our time?

Seems to me there was ONE guy who talked about the air inside
the wing, but you implied that there were "people" that believed the
air inside had something to do with lift. Not honest about things,
trying to make us all look as ignorant as Mx, or trying to raise your
reputation by finding others to step on. It won't work.

MX and someone else talked about wings with no camber. He was
referring to a sheet of plywood with no curvature and was out to
lunch, as usual, but symmetrical wings have no camber. Camber is the
difference between the chord line and the centerline of the airfoil,
he http://www.av8n.com/how/htm/airfoils.html#toc56 scroll
down to Figure 3.12. Or this one:
http://www.centennialofflight.gov/es...ils/TH13G2.jpg

It would help if these "experts" used the correct terminology so the
rest of us misguided pilots knew what they were talking
about.

Dan

"Randy Poe" wrote

BS and more BS.
***********************
And another sock puppet is born. Sheesh.
--
Jim in NC