visualisation of the lift distribution over a wing

[Stealth Pilot[_2_]]

admittedly it is an FA18 but it still comfirms classic lift theory

http://www.airshowaction.com/axalp07/axalp07_227.jpg

Stealth Pilot

[4p1e]

On Aug 1, 7:59*am, Stealth Pilot >
wrote:
> admittedly it is an FA18 but it still comfirms classic lift theory
>
> http://www.airshowaction.com/axalp07/axalp07_227.jpg
>
> Stealth Pilot



Stealth - I have posted the site address to
http://eng-tips.com/viewthread.cfm?qid=251055&page=1 for their
viewing.
Thanks - good stuff.

[wright1902glider]

On Aug 4, 11:05*pm, 4p1e > wrote:
> On Aug 1, 7:59*am, Stealth Pilot >
> wrote:
>
> > admittedly it is an FA18 but it still comfirms classic lift theory
>
Amen! I say to thee, a wing does NOT fly by pushing air down. Rather,
it creates a difference in airspeed between the air on top of the wing
and the air underneath it (relative to gravity or G-forces) which
creates the difference in air pressure which causes what we call
"lift". On hot humid days, reducing air pressure enough can cause
condensation to form. Some people say it even causes clouds.

Now before you flame me, remember that I did not say that a wing does
not deflect some air downward (assuming down is the side toward the
gravity). Only that thats not the primary source of "lift". Which of
course has been known to science since two guys stuck a fan in the end
of a box and blew around a bunch of old hacksaw blades.

Harry Frey

[vaughn[_2_]]

"Wright1902glider" > wrote in message
...
>
>Amen! I say to thee, a wing does NOT fly by pushing air down. Rather,
>it creates a difference in airspeed between the air on top of the wing
>and the air underneath it (relative to gravity or G-forces) which
>creates the difference in air pressure which causes what we call
>"lift".

I decided years ago to "stop deciding" and just believe that life comes
from both theories. If you only look at the picture that started this
thread, you will be left with no doubt about classic lift theory, but if you
had spent as many hours as I have at the back end of a glider tow rope, you
would know that the wake of an airplane is strongly deflected (accelerated)
downward. (New airplane pilots learn about wake turbulence from pictures in
books, but glider CFIs must take their students into the real thing on a
daily basis.) Flying a short distance behind a tow plane, I am always
flying in clean air unless I fly considerably *below* the tow plane.

Even though I know better, from inside a glider on tow it sure looks like
an airplane's lift comes from pushing air down.

Vaughn

[Dan D[_2_]]

"vaughn" > wrote in message ...
>
> "Wright1902glider" > wrote in message
> ...
>>
>>Amen! I say to thee, a wing does NOT fly by pushing air down. Rather,
>>it creates a difference in airspeed between the air on top of the wing
>>and the air underneath it (relative to gravity or G-forces) which
>>creates the difference in air pressure which causes what we call
>>"lift".
>
> I decided years ago to "stop deciding" and just believe that life comes from both theories. If you only look at the
> picture that started this thread, you will be left with no doubt about classic lift theory, but if you had spent as
> many hours as I have at the back end of a glider tow rope, you would know that the wake of an airplane is strongly
> deflected (accelerated) downward. (New airplane pilots learn about wake turbulence from pictures in books, but glider
> CFIs must take their students into the real thing on a daily basis.) Flying a short distance behind a tow plane, I am
> always flying in clean air unless I fly considerably *below* the tow plane.
>
> Even though I know better, from inside a glider on tow it sure looks like an airplane's lift comes from pushing air
> down.
>
> Vaughn
>
>

Hope to do the glider rating thing next year. Sounds like a good add on and BFR resetter...

Equal and opposite reaction, momentum theory, etc. The low pressure on top causes the air to deflect down...and I go up!

Nothing like 720 power turns bumping through the second 360 as you go through your own wake...

[Orval Fairbairn[_2_]]

In article
>,
Wright1902glider > wrote:

> On Aug 4, 11:05*pm, 4p1e > wrote:
> > On Aug 1, 7:59*am, Stealth Pilot >
> > wrote:
> >
> > > admittedly it is an FA18 but it still comfirms classic lift theory
> >
> Amen! I say to thee, a wing does NOT fly by pushing air down. Rather,
> it creates a difference in airspeed between the air on top of the wing
> and the air underneath it (relative to gravity or G-forces) which
> creates the difference in air pressure which causes what we call
> "lift". On hot humid days, reducing air pressure enough can cause
> condensation to form. Some people say it even causes clouds.
>
> Now before you flame me, remember that I did not say that a wing does
> not deflect some air downward (assuming down is the side toward the
> gravity). Only that thats not the primary source of "lift". Which of
> course has been known to science since two guys stuck a fan in the end
> of a box and blew around a bunch of old hacksaw blades.
>
> Harry Frey

Actually, both models describe the same phenomenon. The Bernoulli
principle explains the detailed mechanics of lift, while the momentum
exchange model explains the end product physics of lift. After all, a
symmetric airfoil generates lift by angle of attack, as does the "flat
plate" airfoil, with zero camber.

--
Remove _'s from email address to talk to me.

[Alan Baker]

In article
>,
Wright1902glider > wrote:

> On Aug 4, 11:05*pm, 4p1e > wrote:
> > On Aug 1, 7:59*am, Stealth Pilot >
> > wrote:
> >
> > > admittedly it is an FA18 but it still comfirms classic lift theory
> >
> Amen! I say to thee, a wing does NOT fly by pushing air down. Rather,
> it creates a difference in airspeed between the air on top of the wing
> and the air underneath it (relative to gravity or G-forces) which
> creates the difference in air pressure which causes what we call
> "lift". On hot humid days, reducing air pressure enough can cause
> condensation to form. Some people say it even causes clouds.
>
> Now before you flame me, remember that I did not say that a wing does
> not deflect some air downward (assuming down is the side toward the
> gravity). Only that thats not the primary source of "lift". Which of
> course has been known to science since two guys stuck a fan in the end
> of a box and blew around a bunch of old hacksaw blades.
>
> Harry Frey

You are -- I regret to tell you -- entirely wrong.

Lift is only created if air is deflected downward.

--
Alan Baker
Vancouver, British Columbia
<http://gallery.me.com/alangbaker/100008/DSCF0162/web.jpg>

[Stealth Pilot[_2_]]

On Wed, 5 Aug 2009 20:14:30 -0400, "Dan D"
> wrote:

>
>
>"vaughn" > wrote in message ...
>>
>> "Wright1902glider" > wrote in message
>> ...
>>>
>>>Amen! I say to thee, a wing does NOT fly by pushing air down. Rather,
>>>it creates a difference in airspeed between the air on top of the wing
>>>and the air underneath it (relative to gravity or G-forces) which
>>>creates the difference in air pressure which causes what we call
>>>"lift".
>>
>> I decided years ago to "stop deciding" and just believe that life comes from both theories. If you only look at the
>> picture that started this thread, you will be left with no doubt about classic lift theory, but if you had spent as
>> many hours as I have at the back end of a glider tow rope, you would know that the wake of an airplane is strongly
>> deflected (accelerated) downward. (New airplane pilots learn about wake turbulence from pictures in books, but glider
>> CFIs must take their students into the real thing on a daily basis.) Flying a short distance behind a tow plane, I am
>> always flying in clean air unless I fly considerably *below* the tow plane.
>>
>> Even though I know better, from inside a glider on tow it sure looks like an airplane's lift comes from pushing air
>> down.
>>
>> Vaughn
>>
>>
>
>Hope to do the glider rating thing next year. Sounds like a good add on and BFR resetter...
>
>Equal and opposite reaction, momentum theory, etc. The low pressure on top causes the air to deflect down...and I go up!
>
>Nothing like 720 power turns bumping through the second 360 as you go through your own wake...
>

although that all happens as you describe it is the air below pushing
you up that lifts the wing.
Stealth Pilot

[Jim Logajan]

Wright1902glider > wrote:
> Amen! I say to thee, a wing does NOT fly by pushing air down. Rather,
> it creates a difference in airspeed between the air on top of the wing
> and the air underneath it (relative to gravity or G-forces) which
> creates the difference in air pressure which causes what we call
> "lift".

Well then, you'd better contact NASA and tell them they need to correct the
following:

"Lift occurs when a moving flow of gas is turned by a solid object. The
flow is turned in one direction, and the lift is generated in the opposite
direction, according to Newton's Third Law of action and reaction."

Quoted from:
http://www.grc.nasa.gov/WWW/K-12/airplane/lift1.html

"Lift is created by deflecting a flow of air,"

Quoted from:
http://www.grc.nasa.gov/WWW/K-12/airplane/momntm.html

> On hot humid days, reducing air pressure enough can cause
> condensation to form. Some people say it even causes clouds.

Inserting the word "adiabatically" right after the word "pressure" make the
above a more reasonable assertion.

> Now before you flame me,

Too late! :-)

> remember that I did not say that a wing does
> not deflect some air downward (assuming down is the side toward the
> gravity). Only that thats not the primary source of "lift". Which of
> course has been known to science since two guys stuck a fan in the end
> of a box and blew around a bunch of old hacksaw blades.

Different physical situations. Incorrect analogy.

[Brian Whatcott]

Orval Fairbairn wrote:
>
> Wright1902glider > wrote:

>> Amen! I say to thee, a wing does NOT fly by pushing air down. Rather,
>> it creates a difference in airspeed between the air on top of the wing
>> and the air underneath it (relative to gravity or G-forces) which
>> creates the difference in air pressure which causes what we call
>> "lift". .....
>> Harry Frey
>
> Actually, both models describe the same phenomenon. The Bernoulli
> principle explains the detailed mechanics of lift, while the momentum
> exchange model explains the end product physics of lift. After all, a
> symmetric airfoil generates lift by angle of attack, as does the "flat
> plate" airfoil, with zero camber.
>
What he said

Brian W

[Brian Whatcott]

Stealth Pilot wrote:
> /snip/ it is the air below pushing
> you up that lifts the wing.
> Stealth Pilot

In most circumstances, suction on the upper surface contributes about
2/3 rds of the lift, and pressure on the lower surface contributes about
1/3 rd.
That's one reason which rib stitching for rag wings is a biggy.

Brian W

[cavelamb[_2_]]

brian whatcott wrote:
> Stealth Pilot wrote:
>> /snip/ it is the air below pushing
>> you up that lifts the wing.
>> Stealth Pilot
>
> In most circumstances, suction on the upper surface contributes about
> 2/3 rds of the lift, and pressure on the lower surface contributes about
> 1/3 rd.
> That's one reason which rib stitching for rag wings is a biggy.
>
> Brian W


At high angle of attach - maybe 1/3 on the bottom.
Especially along the leading edge.

At cruise, I believe the lower surface is closer to ambient pressure.

[Alan Baker]

In article >,
brian whatcott > wrote:

> Stealth Pilot wrote:
> > /snip/ it is the air below pushing
> > you up that lifts the wing.
> > Stealth Pilot
>
> In most circumstances, suction on the upper surface contributes about
> 2/3 rds of the lift, and pressure on the lower surface contributes about
> 1/3 rd.
> That's one reason which rib stitching for rag wings is a biggy.
>
> Brian W

Ummmm...

It sort of depends what you mean.

If you mean that suction is actually providing an upward force, you're
quite mistaken.

If you mean that the difference in pressure between upper and lower
surfaces is 2/3 the result of lower pressure on the upper surface, then
you might be right. I don't know.

--
Alan Baker
Vancouver, British Columbia
<http://gallery.me.com/alangbaker/100008/DSCF0162/web.jpg>

[Brian Whatcott]

Alan Baker wrote:
> In article >,
> brian whatcott > wrote:
>
>> Stealth Pilot wrote:
>>> /snip/ it is the air below pushing
>>> you up that lifts the wing.
>>> Stealth Pilot
>> In most circumstances, suction on the upper surface contributes about
>> 2/3 rds of the lift, and pressure on the lower surface contributes about
>> 1/3 rd.
>> That's one reason which rib stitching for rag wings is a biggy.
>>
>> Brian W
>
> Ummmm...
>
> It sort of depends what you mean.
>
> If you mean that suction is actually providing an upward force, you're
> quite mistaken.
>
> If you mean that the difference in pressure between upper and lower
> surfaces is 2/3 the result of lower pressure on the upper surface, then
> you might be right. I don't know.
>

Interesting comment: what would YOU call it when the fabric on the upper
wing surface wants to pull away from the ribs?

Brian W

[Scott[_7_]]

brian whatcott wrote:
> Alan Baker wrote:
>> In article >,
>> brian whatcott > wrote:
>>
>>> Stealth Pilot wrote:
>>>> /snip/ it is the air below pushing
>>>> you up that lifts the wing.
>>>> Stealth Pilot
>>> In most circumstances, suction on the upper surface contributes about
>>> 2/3 rds of the lift, and pressure on the lower surface contributes
>>> about 1/3 rd.
>>> That's one reason which rib stitching for rag wings is a biggy.
>>>
>>> Brian W
>>
>> Ummmm...
>>
>> It sort of depends what you mean.
>>
>> If you mean that suction is actually providing an upward force, you're
>> quite mistaken.
>>
>> If you mean that the difference in pressure between upper and lower
>> surfaces is 2/3 the result of lower pressure on the upper surface,
>> then you might be right. I don't know.
>>
>
> Interesting comment: what would YOU call it when the fabric on the upper
> wing surface wants to pull away from the ribs?
>
> Brian W

It's the "wind" blowing through the bottom surface, inflating the wing
like a balloon ;)

[Alan Baker]

In article >,
brian whatcott > wrote:

> Alan Baker wrote:
> > In article >,
> > brian whatcott > wrote:
> >
> >> Stealth Pilot wrote:
> >>> /snip/ it is the air below pushing
> >>> you up that lifts the wing.
> >>> Stealth Pilot
> >> In most circumstances, suction on the upper surface contributes about
> >> 2/3 rds of the lift, and pressure on the lower surface contributes about
> >> 1/3 rd.
> >> That's one reason which rib stitching for rag wings is a biggy.
> >>
> >> Brian W
> >
> > Ummmm...
> >
> > It sort of depends what you mean.
> >
> > If you mean that suction is actually providing an upward force, you're
> > quite mistaken.
> >
> > If you mean that the difference in pressure between upper and lower
> > surfaces is 2/3 the result of lower pressure on the upper surface, then
> > you might be right. I don't know.
> >
>
> Interesting comment: what would YOU call it when the fabric on the upper
> wing surface wants to pull away from the ribs?

Air pressure from inside the wing pushing up on it more than the air
above is pushing down...

--
Alan Baker
Vancouver, British Columbia
<http://gallery.me.com/alangbaker/100008/DSCF0162/web.jpg>

[Morgans[_2_]]

"Alan Baker" > wrote

> Air pressure from inside the wing pushing up on it more than the air
> above is pushing down...

I hope you are pulling someone's leg, and that your are not that inept in
the field of aerodynamics and physics.
--
Jim in NC

[Alan Baker]

In article >,
"Morgans" > wrote:

> "Alan Baker" > wrote
>
> > Air pressure from inside the wing pushing up on it more than the air
> > above is pushing down...
>
> I hope you are pulling someone's leg, and that your are not that inept in
> the field of aerodynamics and physics.

No, I'm quite serious.

The reduction in *pressure* on the upper surface of the wing cannot
produce any force except downward. A perfect vacuum over the entire
upper surface wouldn't produce any upward force, but simply *zero*
force; allowing the upward force on the lower surface to act alone.

Anyone who thinks that the pressure of a fluid on a surface can act in
any direction but towards the surface is simply wrong.

--
Alan Baker
Vancouver, British Columbia
<http://gallery.me.com/alangbaker/100008/DSCF0162/web.jpg>

[Brian Whatcott]

Alan Baker wrote:

>>>
>> Interesting comment: what would YOU call it when the fabric on the upper
>> wing surface wants to pull away from the ribs?
>
> Air pressure from inside the wing pushing up on it more than the air
> above is pushing down...
>


Let me take a wild guess here: you did physics for an uundergraduate
degree. Is that right?

Brian W

[Steve Hix[_2_]]

In article >,
brian whatcott > wrote:

> Alan Baker wrote:
>
> >>>
> >> Interesting comment: what would YOU call it when the fabric on the upper
> >> wing surface wants to pull away from the ribs?
> >
> > Air pressure from inside the wing pushing up on it more than the air
> > above is pushing down...

For a couple of seconds, perhaps.

Wings aren't typically hermetically sealed.

> Let me take a wild guess here: you did physics for an uundergraduate
> degree. Is that right?
>
> Brian W

[Alan Baker]

In article >,
brian whatcott > wrote:

> Alan Baker wrote:
>
> >>>
> >> Interesting comment: what would YOU call it when the fabric on the upper
> >> wing surface wants to pull away from the ribs?
> >
> > Air pressure from inside the wing pushing up on it more than the air
> > above is pushing down...
> >
>
>
> Let me take a wild guess here: you did physics for an uundergraduate
> degree. Is that right?
>
> Brian W

No. But it doesn't matter.

If the fabric is moving upward, it can only be because there is more
pressure on its bottom surface than there is on its top surface.

--
Alan Baker
Vancouver, British Columbia
<http://gallery.me.com/alangbaker/100008/DSCF0162/web.jpg>

[cavelamb[_2_]]

Steve Hix wrote:
> In article >,
> brian whatcott > wrote:
>
>> Alan Baker wrote:
>>
>>>> Interesting comment: what would YOU call it when the fabric on the upper
>>>> wing surface wants to pull away from the ribs?
>>> Air pressure from inside the wing pushing up on it more than the air
>>> above is pushing down...
>
> For a couple of seconds, perhaps.
>
> Wings aren't typically hermetically sealed.
>
>> Let me take a wild guess here: you did physics for an uundergraduate
>> degree. Is that right?
>>
>> Brian W

I'll take Physics Majors for $500, Alex!

[cavelamb[_2_]]

Alan Baker wrote:
> In article >,
> brian whatcott > wrote:
>
>> Alan Baker wrote:
>>
>>>> Interesting comment: what would YOU call it when the fabric on the upper
>>>> wing surface wants to pull away from the ribs?
>>> Air pressure from inside the wing pushing up on it more than the air
>>> above is pushing down...
>>>
>>
>> Let me take a wild guess here: you did physics for an uundergraduate
>> degree. Is that right?
>>
>> Brian W
>
> No. But it doesn't matter.
>
> If the fabric is moving upward, it can only be because there is more
> pressure on its bottom surface than there is on its top surface.
>

I'm kind of curious about how that higher pressure got on the bottom
of that wing though...

[Brian Whatcott]

Alan Baker wrote:
> In article >,
> brian whatcott > wrote:
>
>> Alan Baker wrote:
>>
>>>> Interesting comment: what would YOU call it when the fabric on the upper
>>>> wing surface wants to pull away from the ribs?
>>> Air pressure from inside the wing pushing up on it more than the air
>>> above is pushing down...
>>>
>>
>> Let me take a wild guess here: you did physics for an uundergraduate
>> degree. Is that right?
>>
>> Brian W
>
> No. But it doesn't matter.
>
> If the fabric is moving upward, it can only be because there is more
> pressure on its bottom surface than there is on its top surface.
>

It seems that you are uncomfortable with the entire concept of suction.
For example, how do you suppose suction cups work?
Or how about a suction pump that happens to be limited to a 30 ft lift?

Well duh, it's also atmospheric pressure that enables suction pumps and
suction cups etc., etc. Yes indeed , but it's an academic issue at
the junior high level, isn't it?

Brian W

[Morgans[_2_]]

"Alan Baker" > wrote
>
> Anyone who thinks that the pressure of a fluid on a surface can act in
> any direction but towards the surface is simply wrong.

I see. You are not lookng at the wing as a system, but taking an
observation at one point only, without reguard to what is happening around
it.

Point made.
--
Jim in NC

[Beryl[_3_]]

Morgans wrote:
> "Alan Baker" > wrote
>> Anyone who thinks that the pressure of a fluid on a surface can act in
>> any direction but towards the surface is simply wrong.
>
> I see. You are not lookng at the wing as a system, but taking an
> observation at one point only, without reguard to what is happening around
> it.
>
> Point made.

He looked inside the wing, at the entire upper surface, at the lower
surface... that pretty much covers most of it. Air can't be in tension.

[cavelamb[_2_]]

brian whatcott wrote:
> Alan Baker wrote:
>> In article >,
>> brian whatcott > wrote:
>>
>>> Alan Baker wrote:
>>>
>>>>> Interesting comment: what would YOU call it when the fabric on the
>>>>> upper wing surface wants to pull away from the ribs?
>>>> Air pressure from inside the wing pushing up on it more than the air
>>>> above is pushing down...
>>>>
>>>
>>> Let me take a wild guess here: you did physics for an uundergraduate
>>> degree. Is that right?
>>>
>>> Brian W
>>
>> No. But it doesn't matter.
>>
>> If the fabric is moving upward, it can only be because there is more
>> pressure on its bottom surface than there is on its top surface.
>>

Have you ever seen the top surface of a fabric covered wing?

The skin does not bulge upwards.

Not usually anyway.

[Jim Logajan]

Beryl > wrote:
> Air can't be in tension.

If it had a stressful day it might become tense. Air can be under a lot of
pressure at times, and work can cause it to get hot. Put under too much
pressure, air can blow a gasket.

That's why it's best to let air blow off steam after a hard day at work and
maybe offer it a smoke with a gin and tonic to cool off:

http://www.bobblum.com/Images/Humor%20Photos/subgenius.jpg

[cavelamb[_2_]]

Jim Logajan wrote:
> Beryl > wrote:
>> Air can't be in tension.
>
> If it had a stressful day it might become tense. Air can be under a lot of
> pressure at times, and work can cause it to get hot. Put under too much
> pressure, air can blow a gasket.
>
> That's why it's best to let air blow off steam after a hard day at work and
> maybe offer it a smoke with a gin and tonic to cool off:
>
> http://www.bobblum.com/Images/Humor%20Photos/subgenius.jpg
>


I think it's about time for a little remedial aerodynamics for the group.

http://www.messybeast.com/dragonqueen/liftdemon.htm



LIFT DEMONS AND THRUST PIXIES

Title of Paper: The Role of Lift Demons and Thrust Pixies in Heavier Than Air Flight

Publication Date: 2004

Abstract: The role of Lift Demons in aeronautics was first explained in 1994 by
Mary Shafer (NASA). Since then, Shafer's work has been explored and revised.
This paper summarises advances in Lift Demon technology over the last decade.

Keywords: Lift Demons, Thrust Pixies, lemon fondant

Authors: Sarah Hartwell, DEF Smith, Peter Rieden, Gavin Bull

[Morgans[_2_]]

"Beryl" > wrote
>
> He looked inside the wing, at the entire upper surface, at the lower
> surface... that pretty much covers most of it. Air can't be in tension.

Yes, but the person that observed that the pressure on the bottom was one
third responsible (for lift) and the low pressure on top was responsible for
two thirds of the lift is also correct, when you look at the wing as a whole
system, even if those fractions are approximate.

I think his view of individual points of observations are splitting
toadstools.

But that is my opinion, and like everyone, we all have but-holes and
opinions.
--
Jim in NC

[Alan Baker]

In article >,
cavelamb > wrote:

> Alan Baker wrote:
> > In article >,
> > brian whatcott > wrote:
> >
> >> Alan Baker wrote:
> >>
> >>>> Interesting comment: what would YOU call it when the fabric on the upper
> >>>> wing surface wants to pull away from the ribs?
> >>> Air pressure from inside the wing pushing up on it more than the air
> >>> above is pushing down...
> >>>
> >>
> >> Let me take a wild guess here: you did physics for an uundergraduate
> >> degree. Is that right?
> >>
> >> Brian W
> >
> > No. But it doesn't matter.
> >
> > If the fabric is moving upward, it can only be because there is more
> > pressure on its bottom surface than there is on its top surface.
> >
>
> I'm kind of curious about how that higher pressure got on the bottom
> of that wing though...

If the curvature of the upper surface lowers the pressure, then even if
the pressure on the lower surface is just the ambient pressure, it will
be *higher* than the upper surface.

--
Alan Baker
Vancouver, British Columbia
<http://gallery.me.com/alangbaker/100008/DSCF0162/web.jpg>

[Alan Baker]

In article >,
brian whatcott > wrote:

> Alan Baker wrote:
> > In article >,
> > brian whatcott > wrote:
> >
> >> Alan Baker wrote:
> >>
> >>>> Interesting comment: what would YOU call it when the fabric on the upper
> >>>> wing surface wants to pull away from the ribs?
> >>> Air pressure from inside the wing pushing up on it more than the air
> >>> above is pushing down...
> >>>
> >>
> >> Let me take a wild guess here: you did physics for an uundergraduate
> >> degree. Is that right?
> >>
> >> Brian W
> >
> > No. But it doesn't matter.
> >
> > If the fabric is moving upward, it can only be because there is more
> > pressure on its bottom surface than there is on its top surface.
> >
>
> It seems that you are uncomfortable with the entire concept of suction.
> For example, how do you suppose suction cups work?

The pressure outside the cup keeps it in place.

> Or how about a suction pump that happens to be limited to a 30 ft lift?

Because a vacuum cannot do any actual pulling, you can only lift water
as far as the pressure allows, right.

>
> Well duh, it's also atmospheric pressure that enables suction pumps and
> suction cups etc., etc. Yes indeed , but it's an academic issue at
> the junior high level, isn't it?

Yup.

--
Alan Baker
Vancouver, British Columbia
<http://gallery.me.com/alangbaker/100008/DSCF0162/web.jpg>

[Alan Baker]

In article >,
"Morgans" > wrote:

> "Alan Baker" > wrote
> >
> > Anyone who thinks that the pressure of a fluid on a surface can act in
> > any direction but towards the surface is simply wrong.
>
> I see. You are not lookng at the wing as a system, but taking an
> observation at one point only, without reguard to what is happening around
> it.
>
> Point made.

Nope.

I'm making the point that the upper surface contributes absolutely *no*
lifting force.

None.

Zero.

In fact, it provides a downward force. Every time.

--
Alan Baker
Vancouver, British Columbia
<http://gallery.me.com/alangbaker/100008/DSCF0162/web.jpg>

[Alan Baker]

In article >,
"Morgans" > wrote:

> "Beryl" > wrote
> >
> > He looked inside the wing, at the entire upper surface, at the lower
> > surface... that pretty much covers most of it. Air can't be in tension.
>
> Yes, but the person that observed that the pressure on the bottom was one
> third responsible (for lift) and the low pressure on top was responsible for
> two thirds of the lift is also correct, when you look at the wing as a whole
> system, even if those fractions are approximate.

Which I correctly identified if the OP meant it in the appropriate terms.

>
> I think his view of individual points of observations are splitting
> toadstools.
>
> But that is my opinion, and like everyone, we all have but-holes and
> opinions.

--
Alan Baker
Vancouver, British Columbia
<http://gallery.me.com/alangbaker/100008/DSCF0162/web.jpg>

[cavelamb[_2_]]

Alan Baker wrote:
> In article >,
> "Morgans" > wrote:
>
>> "Alan Baker" > wrote
>>> Anyone who thinks that the pressure of a fluid on a surface can act in
>>> any direction but towards the surface is simply wrong.
>> I see. You are not lookng at the wing as a system, but taking an
>> observation at one point only, without reguard to what is happening around
>> it.
>>
>> Point made.
>
> Nope.
>
> I'm making the point that the upper surface contributes absolutely *no*
> lifting force.
>
> None.
>
> Zero.
>
> In fact, it provides a downward force. Every time.
>


Sorry, Alan, old boy, I find must disagree.

In actuality, BOTH surfaces are below ambient pressure.
('splain why?)

But without that reduction of the pressure across the top curve of the wing,
the pressure below it can't do much at all, can it?

[Alan Baker]

In article >,
cavelamb > wrote:

> Alan Baker wrote:
> > In article >,
> > "Morgans" > wrote:
> >
> >> "Alan Baker" > wrote
> >>> Anyone who thinks that the pressure of a fluid on a surface can act in
> >>> any direction but towards the surface is simply wrong.
> >> I see. You are not lookng at the wing as a system, but taking an
> >> observation at one point only, without reguard to what is happening around
> >> it.
> >>
> >> Point made.
> >
> > Nope.
> >
> > I'm making the point that the upper surface contributes absolutely *no*
> > lifting force.
> >
> > None.
> >
> > Zero.
> >
> > In fact, it provides a downward force. Every time.
> >
>
>
> Sorry, Alan, old boy, I find must disagree.

Disagree all you want, it won't make the upper surface of the wing
experience anything but a downward force.

>
> In actuality, BOTH surfaces are below ambient pressure.
> ('splain why?)

Bernoulli.

>
> But without that reduction of the pressure across the top curve of the wing,
> the pressure below it can't do much at all, can it?

Which I never disagreed with.

But anyone who thinks the upper surface of the wing is experiencing
anything but a downward force is just sadly misinformed.

--
Alan Baker
Vancouver, British Columbia
<http://gallery.me.com/alangbaker/100008/DSCF0162/web.jpg>

[cavelamb[_2_]]

Alan Baker wrote:
> In article >,
> cavelamb > wrote:
>
>> Alan Baker wrote:
>>> In article >,
>>> "Morgans" > wrote:
>>>
>>>> "Alan Baker" > wrote
>>>>> Anyone who thinks that the pressure of a fluid on a surface can act in
>>>>> any direction but towards the surface is simply wrong.
>>>> I see. You are not lookng at the wing as a system, but taking an
>>>> observation at one point only, without reguard to what is happening around
>>>> it.
>>>>
>>>> Point made.
>>> Nope.
>>>
>>> I'm making the point that the upper surface contributes absolutely *no*
>>> lifting force.
>>>
>>> None.
>>>
>>> Zero.
>>>
>>> In fact, it provides a downward force. Every time.
>>>
>>
>> Sorry, Alan, old boy, I find must disagree.
>
> Disagree all you want, it won't make the upper surface of the wing
> experience anything but a downward force.
>
>> In actuality, BOTH surfaces are below ambient pressure.
>> ('splain why?)
>
> Bernoulli.
>
>> But without that reduction of the pressure across the top curve of the wing,
>> the pressure below it can't do much at all, can it?
>
> Which I never disagreed with.
>
> But anyone who thinks the upper surface of the wing is experiencing
> anything but a downward force is just sadly misinformed.
>

Ok, be that way.

I actually see what you are trying to say.
And, have no real issues with it.

Myopic, but not technically incorrect.

Richard

(That's just my own opinion, but it works for me)

[Alan Baker]

In article >,
cavelamb > wrote:

> Alan Baker wrote:
> > In article >,
> > cavelamb > wrote:
> >
> >> Alan Baker wrote:
> >>> In article >,
> >>> "Morgans" > wrote:
> >>>
> >>>> "Alan Baker" > wrote
> >>>>> Anyone who thinks that the pressure of a fluid on a surface can act in
> >>>>> any direction but towards the surface is simply wrong.
> >>>> I see. You are not lookng at the wing as a system, but taking an
> >>>> observation at one point only, without reguard to what is happening
> >>>> around
> >>>> it.
> >>>>
> >>>> Point made.
> >>> Nope.
> >>>
> >>> I'm making the point that the upper surface contributes absolutely *no*
> >>> lifting force.
> >>>
> >>> None.
> >>>
> >>> Zero.
> >>>
> >>> In fact, it provides a downward force. Every time.
> >>>
> >>
> >> Sorry, Alan, old boy, I find must disagree.
> >
> > Disagree all you want, it won't make the upper surface of the wing
> > experience anything but a downward force.
> >
> >> In actuality, BOTH surfaces are below ambient pressure.
> >> ('splain why?)
> >
> > Bernoulli.
> >
> >> But without that reduction of the pressure across the top curve of the
> >> wing,
> >> the pressure below it can't do much at all, can it?
> >
> > Which I never disagreed with.
> >
> > But anyone who thinks the upper surface of the wing is experiencing
> > anything but a downward force is just sadly misinformed.
> >
>
> Ok, be that way.

Be what way: accurate? Thanks, I think I will.

>
> I actually see what you are trying to say.
> And, have no real issues with it.

Then why say: "I find I must disagree".

>
> Myopic, but not technically incorrect.

Not myopic: accurate. Understand the world AS IT IS.

>
> Richard
>
> (That's just my own opinion, but it works for me)

--
Alan Baker
Vancouver, British Columbia
<http://gallery.me.com/alangbaker/100008/DSCF0162/web.jpg>

[cavelamb[_2_]]

Alan Baker wrote:
> In article >,
> cavelamb > wrote:
>
>> Alan Baker wrote:
>>> In article >,
>>> cavelamb > wrote:
>>>
>>>> Alan Baker wrote:
>>>>> In article >,
>>>>> "Morgans" > wrote:
>>>>>
>>>>>> "Alan Baker" > wrote
>>>>>>> Anyone who thinks that the pressure of a fluid on a surface can act in
>>>>>>> any direction but towards the surface is simply wrong.
>>>>>> I see. You are not lookng at the wing as a system, but taking an
>>>>>> observation at one point only, without reguard to what is happening
>>>>>> around
>>>>>> it.
>>>>>>
>>>>>> Point made.
>>>>> Nope.
>>>>>
>>>>> I'm making the point that the upper surface contributes absolutely *no*
>>>>> lifting force.
>>>>>
>>>>> None.
>>>>>
>>>>> Zero.
>>>>>
>>>>> In fact, it provides a downward force. Every time.
>>>>>
>>>> Sorry, Alan, old boy, I find must disagree.
>>> Disagree all you want, it won't make the upper surface of the wing
>>> experience anything but a downward force.
>>>
>>>> In actuality, BOTH surfaces are below ambient pressure.
>>>> ('splain why?)
>>> Bernoulli.
>>>
>>>> But without that reduction of the pressure across the top curve of the
>>>> wing,
>>>> the pressure below it can't do much at all, can it?
>>> Which I never disagreed with.
>>>
>>> But anyone who thinks the upper surface of the wing is experiencing
>>> anything but a downward force is just sadly misinformed.
>>>
>> Ok, be that way.
>
> Be what way: accurate? Thanks, I think I will.
>
>> I actually see what you are trying to say.
>> And, have no real issues with it.
>
> Then why say: "I find I must disagree".
>
>> Myopic, but not technically incorrect.
>
> Not myopic: accurate. Understand the world AS IT IS.
>
>> Richard
>>
>> (That's just my own opinion, but it works for me)
>

Einstein's greatest gift what that of Relativity.
Each has his own unique perception based on location
relative to an event.

Each sees something different - but ALL can understand
the other's perceptions.

And here you are claiming all truth...

[Alan Baker]

In article >,
cavelamb > wrote:

> Alan Baker wrote:
> > In article >,
> > cavelamb > wrote:
> >
> >> Alan Baker wrote:
> >>> In article >,
> >>> cavelamb > wrote:
> >>>
> >>>> Alan Baker wrote:
> >>>>> In article >,
> >>>>> "Morgans" > wrote:
> >>>>>
> >>>>>> "Alan Baker" > wrote
> >>>>>>> Anyone who thinks that the pressure of a fluid on a surface can act in
> >>>>>>> any direction but towards the surface is simply wrong.
> >>>>>> I see. You are not lookng at the wing as a system, but taking an
> >>>>>> observation at one point only, without reguard to what is happening
> >>>>>> around
> >>>>>> it.
> >>>>>>
> >>>>>> Point made.
> >>>>> Nope.
> >>>>>
> >>>>> I'm making the point that the upper surface contributes absolutely *no*
> >>>>> lifting force.
> >>>>>
> >>>>> None.
> >>>>>
> >>>>> Zero.
> >>>>>
> >>>>> In fact, it provides a downward force. Every time.
> >>>>>
> >>>> Sorry, Alan, old boy, I find must disagree.
> >>> Disagree all you want, it won't make the upper surface of the wing
> >>> experience anything but a downward force.
> >>>
> >>>> In actuality, BOTH surfaces are below ambient pressure.
> >>>> ('splain why?)
> >>> Bernoulli.
> >>>
> >>>> But without that reduction of the pressure across the top curve of the
> >>>> wing,
> >>>> the pressure below it can't do much at all, can it?
> >>> Which I never disagreed with.
> >>>
> >>> But anyone who thinks the upper surface of the wing is experiencing
> >>> anything but a downward force is just sadly misinformed.
> >>>
> >> Ok, be that way.
> >
> > Be what way: accurate? Thanks, I think I will.
> >
> >> I actually see what you are trying to say.
> >> And, have no real issues with it.
> >
> > Then why say: "I find I must disagree".
> >
> >> Myopic, but not technically incorrect.
> >
> > Not myopic: accurate. Understand the world AS IT IS.
> >
> >> Richard
> >>
> >> (That's just my own opinion, but it works for me)
> >
>
> Einstein's greatest gift what that of Relativity.
> Each has his own unique perception based on location
> relative to an event.
>
> Each sees something different - but ALL can understand
> the other's perceptions.
>
> And here you are claiming all truth...

Nope. Not *all* truth. One truth:

The top of a wing doesn't *pull* an aircraft up, it just pushes down
less than the bottom surface pushes up.

And that is the truth. Period. Full stop.

--
Alan Baker
Vancouver, British Columbia
<http://gallery.me.com/alangbaker/100008/DSCF0162/web.jpg>

[Brian Whatcott]

cavelamb wrote:

> Have you ever seen the top surface of a fabric covered wing?
>
> The skin does not bulge upwards.
>
> Not usually anyway.

I find your tone impertinent.

Brian W

[Brian Whatcott]

Alan Baker wrote:
> In article >,
> brian whatcott > wrote:
>
>> Alan Baker wrote:
>>> In article >,
>>> brian whatcott > wrote:
>>>
>>>> Alan Baker wrote:
>>>>
>>>>>> Interesting comment: what would YOU call it when the fabric on the upper
>>>>>> wing surface wants to pull away from the ribs?
>>>>> Air pressure from inside the wing pushing up on it more than the air
>>>>> above is pushing down...
>>>>>
>>>> Let me take a wild guess here: you did physics for an uundergraduate
>>>> degree. Is that right?
>>>>
>>>> Brian W
>>> No. But it doesn't matter.
>>>
>>> If the fabric is moving upward, it can only be because there is more
>>> pressure on its bottom surface than there is on its top surface.
>>>
>> It seems that you are uncomfortable with the entire concept of suction.
>> For example, how do you suppose suction cups work?
>
> The pressure outside the cup keeps it in place.
>
>> Or how about a suction pump that happens to be limited to a 30 ft lift?
>
> Because a vacuum cannot do any actual pulling, you can only lift water
> as far as the pressure allows, right.
>
>> Well duh, it's also atmospheric pressure that enables suction pumps and
>> suction cups etc., etc. Yes indeed , but it's an academic issue at
>> the junior high level, isn't it?
>
> Yup.
>
OK you certainly cut the cookie at Junior High.
Now can we go back to using terms like suction the way 99.99% of the
technical and scientific population understands it? :-)

Brian W

[Brian Whatcott]

Alan Baker wrote:

> Nope.
>
> I'm making the point that the upper surface contributes absolutely *no*
> lifting force.
>
> None.
>
> Zero.
>
> In fact, it provides a downward force. Every time.
>


....and you are making the point that when you are breathing in, you are
not SUCKING air at all. It's atmospheric pressure on your chest that
inspires the air. Wow! Who would have guessed? :-)

Brian W

[Alan Baker]

In article >,
brian whatcott > wrote:

> Alan Baker wrote:
> > In article >,
> > brian whatcott > wrote:
> >
> >> Alan Baker wrote:
> >>> In article >,
> >>> brian whatcott > wrote:
> >>>
> >>>> Alan Baker wrote:
> >>>>
> >>>>>> Interesting comment: what would YOU call it when the fabric on the
> >>>>>> upper
> >>>>>> wing surface wants to pull away from the ribs?
> >>>>> Air pressure from inside the wing pushing up on it more than the air
> >>>>> above is pushing down...
> >>>>>
> >>>> Let me take a wild guess here: you did physics for an uundergraduate
> >>>> degree. Is that right?
> >>>>
> >>>> Brian W
> >>> No. But it doesn't matter.
> >>>
> >>> If the fabric is moving upward, it can only be because there is more
> >>> pressure on its bottom surface than there is on its top surface.
> >>>
> >> It seems that you are uncomfortable with the entire concept of suction.
> >> For example, how do you suppose suction cups work?
> >
> > The pressure outside the cup keeps it in place.
> >
> >> Or how about a suction pump that happens to be limited to a 30 ft lift?
> >
> > Because a vacuum cannot do any actual pulling, you can only lift water
> > as far as the pressure allows, right.
> >
> >> Well duh, it's also atmospheric pressure that enables suction pumps and
> >> suction cups etc., etc. Yes indeed , but it's an academic issue at
> >> the junior high level, isn't it?
> >
> > Yup.
> >
> OK you certainly cut the cookie at Junior High.
> Now can we go back to using terms like suction the way 99.99% of the
> technical and scientific population understands it? :-)
>
> Brian W

No one understands "suction" to actually mean a pulling force. Not since
they tried to pump water out of mines and discovered that they could
only "pull" it a certain number of feet, but no further.

--
Alan Baker
Vancouver, British Columbia
<http://gallery.me.com/alangbaker/100008/DSCF0162/web.jpg>

[et]

On Nov 29, 11:19*pm, Alan Baker > wrote:
> In article >,
>
>
>
>
>
> *cavelamb > wrote:
> > Alan Baker wrote:
> > > In article >,
> > > *"Morgans" > wrote:
>
> > >> "Alan Baker" > wrote
> > >>> Anyone who thinks that the pressure of a fluid on a surface can act in
> > >>> any direction but towards the surface is simply wrong.
> > >> I see. *You are not lookng at the wing as a system, but taking an
> > >> observation at one point only, without reguard to what is happening around
> > >> it.
>
> > >> Point made.
>
> > > Nope.
>
> > > I'm making the point that the upper surface contributes absolutely *no*
> > > lifting force.
>
> > > None.
>
> > > Zero.
>
> > > In fact, it provides a downward force. Every time.
>
> > Sorry, Alan, old boy, I find must disagree.
>
> Disagree all you want, it won't make the upper surface of the wing
> experience anything but a downward force.
>
>
>
> > In actuality, BOTH surfaces are below ambient pressure.
> > ('splain why?)
>
> Bernoulli.
>
>
>
> > But without that reduction of the pressure across the top curve of the wing,
> > the pressure below it can't do much at all, can it?
>
> Which I never disagreed with.
>
> But anyone who thinks the upper surface of the wing is experiencing
> anything but a downward force is just sadly misinformed.
>
> --
> Alan Baker
> Vancouver, British Columbia
> <http://gallery.me.com/alangbaker/100008/DSCF0162/web.jpg>- Hide quoted text -
>
> - Show quoted text -

When I fly my Cheerokee I can detect a slight bulge in the upper
skin. For what it's worth.

Ed

[Alan Baker]

In article
>,
et > wrote:

> On Nov 29, 11:19*pm, Alan Baker > wrote:
> > In article >,
> >
> >
> >
> >
> >
> > *cavelamb > wrote:
> > > Alan Baker wrote:
> > > > In article >,
> > > > *"Morgans" > wrote:
> >
> > > >> "Alan Baker" > wrote
> > > >>> Anyone who thinks that the pressure of a fluid on a surface can act
> > > >>> in
> > > >>> any direction but towards the surface is simply wrong.
> > > >> I see. *You are not lookng at the wing as a system, but taking an
> > > >> observation at one point only, without reguard to what is happening
> > > >> around
> > > >> it.
> >
> > > >> Point made.
> >
> > > > Nope.
> >
> > > > I'm making the point that the upper surface contributes absolutely *no*
> > > > lifting force.
> >
> > > > None.
> >
> > > > Zero.
> >
> > > > In fact, it provides a downward force. Every time.
> >
> > > Sorry, Alan, old boy, I find must disagree.
> >
> > Disagree all you want, it won't make the upper surface of the wing
> > experience anything but a downward force.
> >
> >
> >
> > > In actuality, BOTH surfaces are below ambient pressure.
> > > ('splain why?)
> >
> > Bernoulli.
> >
> >
> >
> > > But without that reduction of the pressure across the top curve of the
> > > wing,
> > > the pressure below it can't do much at all, can it?
> >
> > Which I never disagreed with.
> >
> > But anyone who thinks the upper surface of the wing is experiencing
> > anything but a downward force is just sadly misinformed.
> >
> > --
> > Alan Baker
> > Vancouver, British Columbia
> > <http://gallery.me.com/alangbaker/100008/DSCF0162/web.jpg>- Hide quoted
> > text -
> >
> > - Show quoted text -
>
> When I fly my Cheerokee I can detect a slight bulge in the upper
> skin. For what it's worth.
>
> Ed

Great. Do you think that is caused by the air above the skin pulling on
it?

--
Alan Baker
Vancouver, British Columbia
<http://gallery.me.com/alangbaker/100008/DSCF0162/web.jpg>

[Brian Whatcott]

Alan Baker wrote:
> No one understands "suction" to actually mean a pulling force.


Remember folks: no more talk of sucking soda through a straw!
Just suck it up!

Brian W :-)

[et]

On Nov 30, 8:53*am, Alan Baker > wrote:
> In article
> >,
>
>
>
>
>
> *et > wrote:
> > On Nov 29, 11:19*pm, Alan Baker > wrote:
> > > In article >,
>
> > > *cavelamb > wrote:
> > > > Alan Baker wrote:
> > > > > In article >,
> > > > > *"Morgans" > wrote:
>
> > > > >> "Alan Baker" > wrote
> > > > >>> Anyone who thinks that the pressure of a fluid on a surface can act
> > > > >>> in
> > > > >>> any direction but towards the surface is simply wrong.
> > > > >> I see. *You are not lookng at the wing as a system, but taking an
> > > > >> observation at one point only, without reguard to what is happening
> > > > >> around
> > > > >> it.
>
> > > > >> Point made.
>
> > > > > Nope.
>
> > > > > I'm making the point that the upper surface contributes absolutely *no*
> > > > > lifting force.
>
> > > > > None.
>
> > > > > Zero.
>
> > > > > In fact, it provides a downward force. Every time.
>
> > > > Sorry, Alan, old boy, I find must disagree.
>
> > > Disagree all you want, it won't make the upper surface of the wing
> > > experience anything but a downward force.
>
> > > > In actuality, BOTH surfaces are below ambient pressure.
> > > > ('splain why?)
>
> > > Bernoulli.
>
> > > > But without that reduction of the pressure across the top curve of the
> > > > wing,
> > > > the pressure below it can't do much at all, can it?
>
> > > Which I never disagreed with.
>
> > > But anyone who thinks the upper surface of the wing is experiencing
> > > anything but a downward force is just sadly misinformed.
>
> > > --
> > > Alan Baker
> > > Vancouver, British Columbia
> > > <http://gallery.me.com/alangbaker/100008/DSCF0162/web.jpg>- Hide quoted
> > > text -
>
> > > - Show quoted text -
>
> > When I fly my Cheerokee I can detect a slight bulge in the upper
> > skin. * For what it's worth.
>
> > Ed
>
> Great. Do you think that is caused by the air above the skin pulling on
> it?
>
> --
> Alan Baker
> Vancouver, British Columbia
> <http://gallery.me.com/alangbaker/100008/DSCF0162/web.jpg>- Hide quoted text -
>
> - Show quoted text -

Has to be a pressure differental I would think.

Ed

[Alan Baker]

In article
>,
et > wrote:

> On Nov 30, 8:53*am, Alan Baker > wrote:
> > In article
> > >,
> >
> >
> >
> >
> >
> > *et > wrote:
> > > On Nov 29, 11:19*pm, Alan Baker > wrote:
> > > > In article >,
> >
> > > > *cavelamb > wrote:
> > > > > Alan Baker wrote:
> > > > > > In article >,
> > > > > > *"Morgans" > wrote:
> >
> > > > > >> "Alan Baker" > wrote
> > > > > >>> Anyone who thinks that the pressure of a fluid on a surface can
> > > > > >>> act
> > > > > >>> in
> > > > > >>> any direction but towards the surface is simply wrong.
> > > > > >> I see. *You are not lookng at the wing as a system, but taking an
> > > > > >> observation at one point only, without reguard to what is
> > > > > >> happening
> > > > > >> around
> > > > > >> it.
> >
> > > > > >> Point made.
> >
> > > > > > Nope.
> >
> > > > > > I'm making the point that the upper surface contributes absolutely
> > > > > > *no*
> > > > > > lifting force.
> >
> > > > > > None.
> >
> > > > > > Zero.
> >
> > > > > > In fact, it provides a downward force. Every time.
> >
> > > > > Sorry, Alan, old boy, I find must disagree.
> >
> > > > Disagree all you want, it won't make the upper surface of the wing
> > > > experience anything but a downward force.
> >
> > > > > In actuality, BOTH surfaces are below ambient pressure.
> > > > > ('splain why?)
> >
> > > > Bernoulli.
> >
> > > > > But without that reduction of the pressure across the top curve of
> > > > > the
> > > > > wing,
> > > > > the pressure below it can't do much at all, can it?
> >
> > > > Which I never disagreed with.
> >
> > > > But anyone who thinks the upper surface of the wing is experiencing
> > > > anything but a downward force is just sadly misinformed.
> >
> > > > --
> > > > Alan Baker
> > > > Vancouver, British Columbia
> > > > <http://gallery.me.com/alangbaker/100008/DSCF0162/web.jpg>- Hide quoted
> > > > text -
> >
> > > > - Show quoted text -
> >
> > > When I fly my Cheerokee I can detect a slight bulge in the upper
> > > skin. * For what it's worth.
> >
> > > Ed
> >
> > Great. Do you think that is caused by the air above the skin pulling on
> > it?
> >
> > --
> > Alan Baker
> > Vancouver, British Columbia
> > <http://gallery.me.com/alangbaker/100008/DSCF0162/web.jpg>- Hide quoted
> > text -
> >
> > - Show quoted text -
>
> Has to be a pressure differental I would think.
>
> Ed

Then you understand reality.

:-)

--
Alan Baker
Vancouver, British Columbia
<http://gallery.me.com/alangbaker/100008/DSCF0162/web.jpg>

[Alan Baker]

In article >,
brian whatcott > wrote:

> Alan Baker wrote:
> > No one understands "suction" to actually mean a pulling force.
>
>
> Remember folks: no more talk of sucking soda through a straw!
> Just suck it up!
>
> Brian W :-)

Talk about it all you want...

....just don't pretend that there is a force acting upward on the surface
of the liquid inside the straw...

....because you'll be wrong.

:-)

--
Alan Baker
Vancouver, British Columbia
<http://gallery.me.com/alangbaker/100008/DSCF0162/web.jpg>

[Brian Whatcott]

Alan Baker wrote:
>
>>> No one understands "suction" to actually mean a pulling force.
>>
>> Remember folks: no more talk of sucking soda through a straw!
>> Just suck it up!
>
>... don't pretend that there is a force acting upward on the surface
> of the liquid inside the straw...
>
> ...because you'll be wrong.
>
>
You still don't get it Alan. This level of attention to minutiae is
impressive in Junior High science classes, and paradoxically is quite
correct but trivial. Get over it.

Just so you can savor the general idea - let me phrase the general
concept so it won't trip your OC reaction:
In the general case, two thirds of the lift provided by a wing is due to
the depression over the upper surface - (actually towards the front...)
and a third due to the air flow over the lower surface.

THERE. Are you happy now?

Brian W

[[email protected]]

On Nov 30, 12:19 am, Alan Baker > wrote:

> > > Nope.
>
> > > I'm making the point that the upper surface contributes absolutely *no*
> > > lifting force.
>
> > > None.
>
> > > Zero.
>
> > > In fact, it provides a downward force. Every time.
>
> > Sorry, Alan, old boy, I find must disagree.
>
> Disagree all you want, it won't make the upper surface of the wing
> experience anything but a downward force.
>
>
>
> > In actuality, BOTH surfaces are below ambient pressure.
> > ('splain why?)
>
> Bernoulli.
>
>
>
> > But without that reduction of the pressure across the top curve of the wing,
> > the pressure below it can't do much at all, can it?
>
> Which I never disagreed with.
>
> But anyone who thinks the upper surface of the wing is experiencing
> anything but a downward force is just sadly misinformed.
>
> --
> Alan Baker
> Vancouver, British Columbia
> <http://gallery.me.com/alangbaker/100008/DSCF0162/web.jpg>

Unfortunately for you, Alan, I have some actual observations of a
fabric-covered wing in flight. My Jodel, being a fabric-covered low-
wing aircraft, has a top surface easily observed during flight. The
fabric actually pulls up between the ribs in flight. It actually does.
And near the trailing edge, it's pushed down just a little between the
ribs. Which agrees perfectly with the distribution of lift on airfoil
diagrams.

And don't give me any baloney about pressure inside the wing bulging
the fabric.If that was the case, it would all bulge, not just the 90%
aft of the leading edge.

http://www.cartage.org.lb/en/themes/sciences/physics/FluidDynamics/FlyingDynamics/Aerodynamics/SelectedTopics/Velocity/Velocity/Velocity.htm

I have a picture here of a biplane that had a poor fabric job. The
fabric hadn't been tensioned properly during application, and the view
from above of the wing in flight showed the fabric bulging upward
between the ribs quite amazingly. Positive pressure on the top surface
sure isn't going to do that.

There really isn't much substitute for actual observation. Flights of
imagination are usually way out to lunch. We have a few guys of in
homebuiltairplanes.com who are similarly convinced that all the
experts are wrong and have been for 150 years.

Dan

[Alan Baker]

In article >,
brian whatcott > wrote:

> Alan Baker wrote:
> >
> >>> No one understands "suction" to actually mean a pulling force.
> >>
> >> Remember folks: no more talk of sucking soda through a straw!
> >> Just suck it up!
> >
> >... don't pretend that there is a force acting upward on the surface
> > of the liquid inside the straw...
> >
> > ...because you'll be wrong.
> >
> >
> You still don't get it Alan. This level of attention to minutiae is
> impressive in Junior High science classes, and paradoxically is quite
> correct but trivial. Get over it.
>
> Just so you can savor the general idea - let me phrase the general
> concept so it won't trip your OC reaction:
> In the general case, two thirds of the lift provided by a wing is due to
> the depression over the upper surface - (actually towards the front...)
> and a third due to the air flow over the lower surface.
>
> THERE. Are you happy now?
>
> Brian W

I was happy to begin with. Read my initial reply:

"Ummmm...

It sort of depends what you mean.

If you mean that suction is actually providing an upward force, you're
quite mistaken.

If you mean that the difference in pressure between upper and lower
surfaces is 2/3 the result of lower pressure on the upper surface, then
you might be right. I don't know."

You see, I never had any problem sorting out the "minutiae" from the
important. But a whole bunch of people (well, *some* people) jumped in
and certainly made statements that they actually believe the air was
pulling up on the wing.

--
Alan Baker
Vancouver, British Columbia
<http://gallery.me.com/alangbaker/100008/DSCF0162/web.jpg>

[Alan Baker]

In article
>,
wrote:

> On Nov 30, 12:19 am, Alan Baker > wrote:
>
> > > > Nope.
> >
> > > > I'm making the point that the upper surface contributes absolutely *no*
> > > > lifting force.
> >
> > > > None.
> >
> > > > Zero.
> >
> > > > In fact, it provides a downward force. Every time.
> >
> > > Sorry, Alan, old boy, I find must disagree.
> >
> > Disagree all you want, it won't make the upper surface of the wing
> > experience anything but a downward force.
> >
> >
> >
> > > In actuality, BOTH surfaces are below ambient pressure.
> > > ('splain why?)
> >
> > Bernoulli.
> >
> >
> >
> > > But without that reduction of the pressure across the top curve of the
> > > wing,
> > > the pressure below it can't do much at all, can it?
> >
> > Which I never disagreed with.
> >
> > But anyone who thinks the upper surface of the wing is experiencing
> > anything but a downward force is just sadly misinformed.
> >
> > --
> > Alan Baker
> > Vancouver, British Columbia
> > <http://gallery.me.com/alangbaker/100008/DSCF0162/web.jpg>
>
> Unfortunately for you, Alan, I have some actual observations of a
> fabric-covered wing in flight. My Jodel, being a fabric-covered low-
> wing aircraft, has a top surface easily observed during flight. The
> fabric actually pulls up between the ribs in flight. It actually does.
> And near the trailing edge, it's pushed down just a little between the
> ribs. Which agrees perfectly with the distribution of lift on airfoil
> diagrams.

And it is only deflected upward by the fact that the air *pushing* on
the bottom of the fabric's surface is doing so with greater force than
the air *pushing* down from above.

>
> And don't give me any baloney about pressure inside the wing bulging
> the fabric.If that was the case, it would all bulge, not just the 90%
> aft of the leading edge.

I would only bulge where the air is at lower pressure than the air
inside the wing.

>
> http://www.cartage.org.lb/en/themes/sciences/physics/FluidDynamics/FlyingDynam
> ics/Aerodynamics/SelectedTopics/Velocity/Velocity/Velocity.htm
>
> I have a picture here of a biplane that had a poor fabric job. The
> fabric hadn't been tensioned properly during application, and the view
> from above of the wing in flight showed the fabric bulging upward
> between the ribs quite amazingly. Positive pressure on the top surface
> sure isn't going to do that.

Not on it's own, no. But greater positive pressure on the bottom surface
than on the top surface sure is and does.

>
> There really isn't much substitute for actual observation. Flights of
> imagination are usually way out to lunch. We have a few guys of in
> homebuiltairplanes.com who are similarly convinced that all the
> experts are wrong and have been for 150 years.

Observation can lead you astray: and that is clearly the case here if
you actually think that air can *pull* on a surface.

--
Alan Baker
Vancouver, British Columbia
<http://gallery.me.com/alangbaker/100008/DSCF0162/web.jpg>

[Alan Baker]

In article >,
Alan Baker > wrote:

> > > > But without that reduction of the pressure across the top curve of the
> > > > wing,
> > > > the pressure below it can't do much at all, can it?
> > >
> > > Which I never disagreed with.
> > >
> > > But anyone who thinks the upper surface of the wing is experiencing
> > > anything but a downward force is just sadly misinformed.
> > >
> >
> > Unfortunately for you, Alan, I have some actual observations of a
> > fabric-covered wing in flight. My Jodel, being a fabric-covered low-
> > wing aircraft, has a top surface easily observed during flight. The
> > fabric actually pulls up between the ribs in flight. It actually does.
> > And near the trailing edge, it's pushed down just a little between the
> > ribs. Which agrees perfectly with the distribution of lift on airfoil
> > diagrams.
>
> And it is only deflected upward by the fact that the air *pushing* on
> the bottom of the fabric's surface is doing so with greater force than
> the air *pushing* down from above.
>
> >
> > And don't give me any baloney about pressure inside the wing bulging
> > the fabric.If that was the case, it would all bulge, not just the 90%
> > aft of the leading edge.
>
> I would only bulge where the air is at lower pressure than the air
> inside the wing.
>
> >
> > http://www.cartage.org.lb/en/themes/sciences/physics/FluidDynamics/FlyingDyn
> > am
> > ics/Aerodynamics/SelectedTopics/Velocity/Velocity/Velocity.htm
> >
> > I have a picture here of a biplane that had a poor fabric job. The
> > fabric hadn't been tensioned properly during application, and the view
> > from above of the wing in flight showed the fabric bulging upward
> > between the ribs quite amazingly. Positive pressure on the top surface
> > sure isn't going to do that.
>
> Not on it's own, no. But greater positive pressure on the bottom surface
> than on the top surface sure is and does.
>
> >
> > There really isn't much substitute for actual observation. Flights of
> > imagination are usually way out to lunch. We have a few guys of in
> > homebuiltairplanes.com who are similarly convinced that all the
> > experts are wrong and have been for 150 years.
>
> Observation can lead you astray: and that is clearly the case here if
> you actually think that air can *pull* on a surface.

BTW, Brian:

This is precisely why I bother with "minutiae". The PP clearly believes
that the air is actually pulling...

--
Alan Baker
Vancouver, British Columbia
<http://gallery.me.com/alangbaker/100008/DSCF0162/web.jpg>

[Scott[_7_]]

Alan Baker wrote:

>
> This is precisely why I bother with "minutiae". The PP clearly believes
> that the air is actually pulling...


>

I'm with Einstein. It's relative. If I'm floating above a wing in
flight and the wing is "climbing" it looks like it's being sucked toward
me. If I'm floating below a wing in flight and the wing is "climbing"
it looks like it's being pushed away from me.

In all reality, as an airplane USER, I don't really care what is really
happening. I know how to manipulate the controls I have to make it do
what I want it to do.

[Scott[_7_]]

Alan Baker wrote:

>
> Observation can lead you astray: and that is clearly the case here if
> you actually think that air can *pull* on a surface.
>

Why can't air PULL on a surface? Air is made up of molecules.
Molecules have mass. Anything with mass can attract anything else with
mass, can't it?

[Alan Baker]

In article >,
Scott > wrote:

> Alan Baker wrote:
>
> >
> > Observation can lead you astray: and that is clearly the case here if
> > you actually think that air can *pull* on a surface.
> >
>
> Why can't air PULL on a surface? Air is made up of molecules.
> Molecules have mass. Anything with mass can attract anything else with
> mass, can't it?

Gravity?

You're not serious.

--
Alan Baker
Vancouver, British Columbia
<http://gallery.me.com/alangbaker/100008/DSCF0162/web.jpg>

[Ed]

On Sat, 28 Nov 2009 19:07:16 -0600, brian whatcott
> wrote:

>Stealth Pilot wrote:
>> /snip/ it is the air below pushing
>> you up that lifts the wing.
>> Stealth Pilot
>
>In most circumstances, suction on the upper surface contributes about
>2/3 rds of the lift, and pressure on the lower surface contributes about
>1/3 rd.
>That's one reason which rib stitching for rag wings is a biggy.
>
>Brian W

I have never noticed the fabric lifting on my wings, however I have
seen the fuel siphon out of a wing tank due to an improperly applied
fuel cap.

[Alan Baker]

In article >,
Ed > wrote:

> On Sat, 28 Nov 2009 19:07:16 -0600, brian whatcott
> > wrote:
>
> >Stealth Pilot wrote:
> >> /snip/ it is the air below pushing
> >> you up that lifts the wing.
> >> Stealth Pilot
> >
> >In most circumstances, suction on the upper surface contributes about
> >2/3 rds of the lift, and pressure on the lower surface contributes about
> >1/3 rd.
> >That's one reason which rib stitching for rag wings is a biggy.
> >
> >Brian W
>
> I have never noticed the fabric lifting on my wings, however I have
> seen the fuel siphon out of a wing tank due to an improperly applied
> fuel cap.

And greater pressure in the tank than outside of it...

--
Alan Baker
Vancouver, British Columbia
<http://gallery.me.com/alangbaker/100008/DSCF0162/web.jpg>

[Scott[_7_]]

Alan Baker wrote:
> In article >,
> Scott > wrote:
>
>> Alan Baker wrote:
>>
>>> Observation can lead you astray: and that is clearly the case here if
>>> you actually think that air can *pull* on a surface.
>>>
>> Why can't air PULL on a surface? Air is made up of molecules.
>> Molecules have mass. Anything with mass can attract anything else with
>> mass, can't it?
>
> Gravity?
>
> You're not serious.
>
Anti-gravity in this case. If air can push something, why can't it pull
something?

[Scott[_7_]]

Alan Baker wrote:
> In article >,
> Ed > wrote:
>
>> On Sat, 28 Nov 2009 19:07:16 -0600, brian whatcott
>> > wrote:
>>
>>> Stealth Pilot wrote:
>>>> /snip/ it is the air below pushing
>>>> you up that lifts the wing.
>>>> Stealth Pilot
>>> In most circumstances, suction on the upper surface contributes about
>>> 2/3 rds of the lift, and pressure on the lower surface contributes about
>>> 1/3 rd.
>>> That's one reason which rib stitching for rag wings is a biggy.
>>>
>>> Brian W
>> I have never noticed the fabric lifting on my wings, however I have
>> seen the fuel siphon out of a wing tank due to an improperly applied
>> fuel cap.
>
> And greater pressure in the tank than outside of it...
>
Right, but in a sealed metal tank, is all that other fuel PUSHING the
fuel out of the vent since air can't PULL it out?

[Alan Baker]

In article >,
Scott > wrote:

> Alan Baker wrote:
> > In article >,
> > Scott > wrote:
> >
> >> Alan Baker wrote:
> >>
> >>> Observation can lead you astray: and that is clearly the case here if
> >>> you actually think that air can *pull* on a surface.
> >>>
> >> Why can't air PULL on a surface? Air is made up of molecules.
> >> Molecules have mass. Anything with mass can attract anything else with
> >> mass, can't it?
> >
> > Gravity?
> >
> > You're not serious.
> >
> Anti-gravity in this case. If air can push something, why can't it pull
> something?

Because the push is caused by the impact of countless air molecules with
the surface of wing. If those collisions fall to zero (i.e. in a perfect
vacuum) then there is zero push.

But there is no set of circumstances that can make the number of
collisions be negative.

--
Alan Baker
Vancouver, British Columbia
<http://gallery.me.com/alangbaker/100008/DSCF0162/web.jpg>

[Jim Logajan]

Scott > wrote:
> Alan Baker wrote:
>> In article >,
>> Scott > wrote:
>>
>>> Alan Baker wrote:
>>>
>>>> Observation can lead you astray: and that is clearly the case here
>>>> if you actually think that air can *pull* on a surface.
>>>>
>>> Why can't air PULL on a surface? Air is made up of molecules.
>>> Molecules have mass. Anything with mass can attract anything else
>>> with mass, can't it?
>>
>> Gravity?
>>
>> You're not serious.
>>
> Anti-gravity in this case. If air can push something, why can't it
> pull something?

No need to postulate anti-gravity to find a case where air can "pull" on a
surface - just invoke van der Waals force! :-)

[Alan Baker]

In article >,
Scott > wrote:

> Alan Baker wrote:
> > In article >,
> > Ed > wrote:
> >
> >> On Sat, 28 Nov 2009 19:07:16 -0600, brian whatcott
> >> > wrote:
> >>
> >>> Stealth Pilot wrote:
> >>>> /snip/ it is the air below pushing
> >>>> you up that lifts the wing.
> >>>> Stealth Pilot
> >>> In most circumstances, suction on the upper surface contributes about
> >>> 2/3 rds of the lift, and pressure on the lower surface contributes about
> >>> 1/3 rd.
> >>> That's one reason which rib stitching for rag wings is a biggy.
> >>>
> >>> Brian W
> >> I have never noticed the fabric lifting on my wings, however I have
> >> seen the fuel siphon out of a wing tank due to an improperly applied
> >> fuel cap.
> >
> > And greater pressure in the tank than outside of it...
> >
> Right, but in a sealed metal tank, is all that other fuel PUSHING the
> fuel out of the vent since air can't PULL it out?

First of all, the tank is not completely sealed. If it were, the fuel
pumps would soon have difficult pumping the fuel out of the tank.

So, yes, the greater pressure inside the tank is pushing the fuel out.

--
Alan Baker
Vancouver, British Columbia
<http://gallery.me.com/alangbaker/100008/DSCF0162/web.jpg>

[Alan Baker]

In article >,
Jim Logajan > wrote:

> Scott > wrote:
> > Alan Baker wrote:
> >> In article >,
> >> Scott > wrote:
> >>
> >>> Alan Baker wrote:
> >>>
> >>>> Observation can lead you astray: and that is clearly the case here
> >>>> if you actually think that air can *pull* on a surface.
> >>>>
> >>> Why can't air PULL on a surface? Air is made up of molecules.
> >>> Molecules have mass. Anything with mass can attract anything else
> >>> with mass, can't it?
> >>
> >> Gravity?
> >>
> >> You're not serious.
> >>
> > Anti-gravity in this case. If air can push something, why can't it
> > pull something?
>
> No need to postulate anti-gravity to find a case where air can "pull" on a
> surface - just invoke van der Waals force! :-)

Please, don't!

--
Alan Baker
Vancouver, British Columbia
<http://gallery.me.com/alangbaker/100008/DSCF0162/web.jpg>

[Jim Logajan]

Alan Baker > wrote:
> Because the push is caused by the impact of countless air molecules
> with the surface of wing. If those collisions fall to zero (i.e. in a
> perfect vacuum) then there is zero push.
>
> But there is no set of circumstances that can make the number of
> collisions be negative.

Pedantically speaking, outgassing would occur for a while that would create
a force on your wing surface when it is exposed to a vacuum. Pedantically
speaking, I don't see why those couldn't be called negative collisions.

(Last worked on a fancy high-vaccum system back in college, wherein my lab
mate and I attempted to replicate the Lamb-Retherford experiment.)

[Alan Baker]

In article >,
Jim Logajan > wrote:

> Alan Baker > wrote:
> > Because the push is caused by the impact of countless air molecules
> > with the surface of wing. If those collisions fall to zero (i.e. in a
> > perfect vacuum) then there is zero push.
> >
> > But there is no set of circumstances that can make the number of
> > collisions be negative.
>
> Pedantically speaking, outgassing would occur for a while that would create
> a force on your wing surface when it is exposed to a vacuum. Pedantically
> speaking, I don't see why those couldn't be called negative collisions.

The force they'd create would be in the same direction as the force of
regular collisions: toward the surface. If the outgassing molecules have
momentum away from the surface then the surface must experience a change
in momentum in the opposite direction.

--
Alan Baker
Vancouver, British Columbia
<http://gallery.me.com/alangbaker/100008/DSCF0162/web.jpg>

[[email protected]]

On Dec 1, 6:05*pm, Jim Logajan > wrote:
> Scott > wrote:
> > Alan Baker wrote:
> >> In article >,
> >> *Scott > wrote:
>
> >>> Alan Baker wrote:
>
> >>>> Observation can lead you astray: and that is clearly the case here
> >>>> if you actually think that air can *pull* on a surface.
>
> >>> Why can't air PULL on a surface? *Air is made up of molecules.
> >>> Molecules have mass. *Anything with mass can attract anything else
> >>> with mass, can't it?
>
> >> Gravity?
>
> >> You're not serious.
>
> > Anti-gravity in this case. *If air can push something, why can't it
> > pull something?
>
> No need to postulate anti-gravity to find a case where air can "pull" on a
> surface - just invoke van der Waals force! :-)

I think I see what Alan is getting at: While there is low pressure
on the top of the wing, there is still pressure. There isn't an
absolute vacuum, so some pressure is there. But its a lot less than
that below the wing, so the wing moves upward. As he says, air can't
suck the wing upward, but its pressure can be reduced enough that the
pressure below displaces the wing upward.

Semantics. We argue about downwash (Newton) and pressure
differential (Bernoulli) but they're just two symbiotic approaches to
the same phenomenon. Shoot, the air flowing off the top of the wing is
accelerated and moving downward with respect to the flight path, so
downwash is to be expected.

But there's no downwash when a balloon rises. Just displacement.

Dan

[Jim Logajan]

Alan Baker > wrote:
> Because the push is caused by the impact of countless air molecules
> with the surface of wing. If those collisions fall to zero (i.e. in a
> perfect vacuum) then there is zero push.

I don't see what a change in air density (such as taking the extreme case
of a vacuum) has to do with lift. Unless you are claiming density change as
a requirement?

I believe lift can be reasonably computed using inviscid _incompressible_
flow theory (e.g. as far back as Kutta's 1902 dissertation,) so I don't see
why any change in _density_ - much less the vacuum edge case - needs to be
invoked.

[Beryl[_3_]]

Jim Logajan wrote:
> Alan Baker > wrote:
>> Because the push is caused by the impact of countless air molecules
>> with the surface of wing. If those collisions fall to zero (i.e. in a
>> perfect vacuum) then there is zero push.
>
> I don't see what a change in air density (such as taking the extreme case
> of a vacuum) has to do with lift.

I'm going to build a thick wing, real thick! About 10,000 feet thick.
While the bottom surface of the wing sits at 29.92" sea level
atmospheric pressure, the upper surface will be *way* up there, in a
lower-pressure area. This airplane is gonna to lift off the ground at
zero airspeed with no power.

[Steve Hix[_2_]]

In article >,
Scott > wrote:

> Alan Baker wrote:
> > In article >,
> > Scott > wrote:
> >
> >> Alan Baker wrote:
> >>
> >>> Observation can lead you astray: and that is clearly the case here if
> >>> you actually think that air can *pull* on a surface.
> >>>
> >> Why can't air PULL on a surface? Air is made up of molecules.
> >> Molecules have mass. Anything with mass can attract anything else with
> >> mass, can't it?
> >
> > Gravity?
> >
> > You're not serious.
> >
> Anti-gravity in this case. If air can push something, why can't it pull
> something?

It does, but the tiny resulting forces are completely swamped by things
like van der Waals force, static electric charges, magnetic fields, and
any number of things that are usually quite happily ignored by us in
normal life.

[Steve Hix[_2_]]

In article >,
Beryl > wrote:

> Jim Logajan wrote:
> > Alan Baker > wrote:
> >> Because the push is caused by the impact of countless air molecules
> >> with the surface of wing. If those collisions fall to zero (i.e. in a
> >> perfect vacuum) then there is zero push.
> >
> > I don't see what a change in air density (such as taking the extreme case
> > of a vacuum) has to do with lift.
>
> I'm going to build a thick wing, real thick! About 10,000 feet thick.
> While the bottom surface of the wing sits at 29.92" sea level
> atmospheric pressure, the upper surface will be *way* up there, in a
> lower-pressure area. This airplane is gonna to lift off the ground at
> zero airspeed with no power.

Only if you make it from monatomic Unobtanium. Only thing light enough
for the job.

[Alan Baker]

In article >,
Jim Logajan > wrote:

> Alan Baker > wrote:
> > Because the push is caused by the impact of countless air molecules
> > with the surface of wing. If those collisions fall to zero (i.e. in a
> > perfect vacuum) then there is zero push.
>
> I don't see what a change in air density (such as taking the extreme case
> of a vacuum) has to do with lift. Unless you are claiming density change as
> a requirement?
>
> I believe lift can be reasonably computed using inviscid _incompressible_
> flow theory (e.g. as far back as Kutta's 1902 dissertation,) so I don't see
> why any change in _density_ - much less the vacuum edge case - needs to be
> invoked.

Any change in pressure is *by definition* a change in the number of
particles in the fluid that are impacting the surface.

I never mentioned density.

--
Alan Baker
Vancouver, British Columbia
<http://gallery.me.com/alangbaker/100008/DSCF0162/web.jpg>

[Brian Whatcott]

Alan Baker wrote:
/snip/
>>>> I have never noticed the fabric lifting on my wings, however I have
>>>> seen the fuel siphon out of a wing tank due to an improperly applied
>>>> fuel cap.
>>> And greater pressure in the tank than outside of it...
>>>
>> Right, but in a sealed metal tank, is all that other fuel PUSHING the
>> fuel out of the vent since air can't PULL it out?
>
> First of all, the tank is not completely sealed. If it were, the fuel
> pumps would soon have difficult pumping the fuel out of the tank.
>
> So, yes, the greater pressure inside the tank is pushing the fuel out.
>

Hmmm...it probably goes more like this: there's a 100 mph? wind past an
open port, with some venturi effect certainly, but plenty of
turbulence. If you beat up the surface with a gusty blow, it gets
wavelets which can lap the filler and blow out the fuel.

Which reminds me of that trick that suction pumps use for high lift.

As you probably know, if you pump down even to a vacuum above a tall
3water pipe, the water will not rise more than about 30 ft - (if it were
mercury, it would not rise more than 29.92 inches on a standard day,
remember?)

Anyway, the mine engineers who want to pump up water MORE than 30 ft,
say 40 ft without placing a force pump at the foot of the head, blow air
into the water column which has the effect of reducing the density of
the mix. If the relative density goes down from 1.0 to 0.5 they COULD
pump up to nearer 60 ft. How bout that!

Brian W

[Scott[_7_]]

Steve Hix wrote:

> any number of things that are usually quite happily ignored by us in
> normal life.


EXACTLY!! ;) I don't have to know if air pushes or sucks (although I'm
quite sure it SUCKS in L.A.) to control the airplane to do what I want
it to do.

[Jim Logajan]

Alan Baker > wrote:
> In article >,
> Jim Logajan > wrote:
>
>> Alan Baker > wrote:
>> > Because the push is caused by the impact of countless air molecules
>> > with the surface of wing. If those collisions fall to zero (i.e. in
>> > a perfect vacuum) then there is zero push.
>>
>> I don't see what a change in air density (such as taking the extreme
>> case of a vacuum) has to do with lift. Unless you are claiming
>> density change as a requirement?
>>
>> I believe lift can be reasonably computed using inviscid
>> _incompressible_ flow theory (e.g. as far back as Kutta's 1902
>> dissertation,) so I don't see why any change in _density_ - much less
>> the vacuum edge case - needs to be invoked.
>
> Any change in pressure is *by definition* a change in the number of
> particles in the fluid that are impacting the surface.

That assertion is incorrect. You are no dummy so I'm sure you'll correct it
when you realize the errors.

> I never mentioned density.

Sorry, but you used the word "vacuum." The notable characteristic of a
vacuum is that its density is zero.

[Robert Bonomi]

In article >,
Scott > wrote:
>Alan Baker wrote:
>> In article >,
>> Scott > wrote:
>>
>>> Alan Baker wrote:
>>>
>>>> Observation can lead you astray: and that is clearly the case here if
>>>> you actually think that air can *pull* on a surface.
>>>>
>>> Why can't air PULL on a surface? Air is made up of molecules.
>>> Molecules have mass. Anything with mass can attract anything else with
>>> mass, can't it?
>>
>> Gravity?
>>
>> You're not serious.
>>
>Anti-gravity in this case. If air can push something, why can't it pull
>something?

Quote: "There are two things you need to know to be an engineer:
1) F = M x A
2) you can't push on a rope."

Your question involves a violation of rule #2.

[Brian Whatcott]

Robert Bonomi wrote:

>
> Quote: "There are two things you need to know to be an engineer:
> 1) F = M x A
> 2) you can't push on a rope."
>
> Your question involves a violation of rule #2.
>
>

Hehe... If you push downwards on a tight rope carefully enough,
you can qualify as a tightrope walker?? :-)

Brian W

[Alan Baker]

In article >,
Jim Logajan > wrote:

> Alan Baker > wrote:
> > In article >,
> > Jim Logajan > wrote:
> >
> >> Alan Baker > wrote:
> >> > Because the push is caused by the impact of countless air molecules
> >> > with the surface of wing. If those collisions fall to zero (i.e. in
> >> > a perfect vacuum) then there is zero push.
> >>
> >> I don't see what a change in air density (such as taking the extreme
> >> case of a vacuum) has to do with lift. Unless you are claiming
> >> density change as a requirement?
> >>
> >> I believe lift can be reasonably computed using inviscid
> >> _incompressible_ flow theory (e.g. as far back as Kutta's 1902
> >> dissertation,) so I don't see why any change in _density_ - much less
> >> the vacuum edge case - needs to be invoked.
> >
> > Any change in pressure is *by definition* a change in the number of
> > particles in the fluid that are impacting the surface.
>
> That assertion is incorrect. You are no dummy so I'm sure you'll correct it
> when you realize the errors.

Sorry, but it's not. Pressure is created by particle collisions.

>
> > I never mentioned density.
>
> Sorry, but you used the word "vacuum." The notable characteristic of a
> vacuum is that its density is zero.

That is *a* notable characteristic.

--
Alan Baker
Vancouver, British Columbia
<http://gallery.me.com/alangbaker/100008/DSCF0162/web.jpg>

[Alan Baker]

In article >,
brian whatcott > wrote:

> Alan Baker wrote:
> /snip/
> >>>> I have never noticed the fabric lifting on my wings, however I have
> >>>> seen the fuel siphon out of a wing tank due to an improperly applied
> >>>> fuel cap.
> >>> And greater pressure in the tank than outside of it...
> >>>
> >> Right, but in a sealed metal tank, is all that other fuel PUSHING the
> >> fuel out of the vent since air can't PULL it out?
> >
> > First of all, the tank is not completely sealed. If it were, the fuel
> > pumps would soon have difficult pumping the fuel out of the tank.
> >
> > So, yes, the greater pressure inside the tank is pushing the fuel out.
> >
>
> Hmmm...it probably goes more like this: there's a 100 mph? wind past an
> open port, with some venturi effect certainly, but plenty of
> turbulence. If you beat up the surface with a gusty blow, it gets
> wavelets which can lap the filler and blow out the fuel.
>
> Which reminds me of that trick that suction pumps use for high lift.
>
> As you probably know, if you pump down even to a vacuum above a tall
> 3water pipe, the water will not rise more than about 30 ft - (if it were
> mercury, it would not rise more than 29.92 inches on a standard day,
> remember?)
>
> Anyway, the mine engineers who want to pump up water MORE than 30 ft,
> say 40 ft without placing a force pump at the foot of the head, blow air
> into the water column which has the effect of reducing the density of
> the mix. If the relative density goes down from 1.0 to 0.5 they COULD
> pump up to nearer 60 ft. How bout that!
>
> Brian W

How about it? It still doesn't change the physical reality that air
doesn't *pull* on the wings.

--
Alan Baker
Vancouver, British Columbia
<http://gallery.me.com/alangbaker/100008/DSCF0162/web.jpg>

[Brian Whatcott]

Alan Baker wrote:
> In article >,
> Jim Logajan > wrote:

>>> Any change in pressure is *by definition* a change in the number of
>>> particles in the fluid that are impacting the surface.

>> That assertion is incorrect. You are no dummy so I'm sure you'll correct it
>> when you realize the errors.
>
> Sorry, but it's not. Pressure is created by particle collisions.

Hmmm...looks like Jim expected too much from you: the kinetic theory of
gases has it that pressure may be computed from the temperature AND the
density of gases... that is to say, by retaining the SAME molar quantity
of gas, and raising its temperature (which translates to a higher
velocity), the pressure is increased P.V = R.t and all that....

Put it another way: each "hotter" molecule reverses direction at a
surface with greater force.

Brian W

[Brian Whatcott]

Alan Baker wrote:

>>>>>> I have never noticed the fabric lifting on my wings, however I have
>>>>>> seen the fuel siphon out of a wing tank due to an improperly applied
>>>>>> fuel cap.
>>>>> And greater pressure in the tank than outside of it...

/snip/
>>> So, yes, the greater pressure inside the tank is pushing the fuel out.
>>>
>> Hmmm...it probably goes more like this: there's a 100 mph? wind past an
>> open port, with some venturi effect certainly, but plenty of
>> turbulence. If you beat up the surface with a gusty blow, it gets
>> wavelets which can lap the filler and blow out the fuel.

> How about it? It still doesn't change the physical reality that air
> doesn't *pull* on the wings.
>


You're still singing the last hymn, Alan.

We are now discussing how an open tank, with a 100 mph wind blowing over
its top, can lose its fuel over the top. Do you think the tank has
GREATER pressure due to the venturi effect of the airflow?

Brian W

[Alan Baker]

In article >,
brian whatcott > wrote:

> Alan Baker wrote:
> > In article >,
> > Jim Logajan > wrote:
>
> >>> Any change in pressure is *by definition* a change in the number of
> >>> particles in the fluid that are impacting the surface.
>
> >> That assertion is incorrect. You are no dummy so I'm sure you'll correct
> >> it
> >> when you realize the errors.
> >
> > Sorry, but it's not. Pressure is created by particle collisions.
>
> Hmmm...looks like Jim expected too much from you: the kinetic theory of
> gases has it that pressure may be computed from the temperature AND the
> density of gases... that is to say, by retaining the SAME molar quantity
> of gas, and raising its temperature (which translates to a higher
> velocity), the pressure is increased P.V = R.t and all that....
>
> Put it another way: each "hotter" molecule reverses direction at a
> surface with greater force.
>
> Brian W

I'm perfectly aware of that, but that hardly matters for the scope of
our discussion of the effect of pressure on a wing. The point I'm making
is that all else being equal, more collisions means higher pressure and
fewer means lower pressure, but that pressure is therefore always a
positive value that acts toward the surface to which it is applied.

It is *never* acting away from that surface; i.e. "pulling".

That is the only reason I mentioned a vacuum, because it is a situation
in which there is *by definition* zero absolute pressure.

--
Alan Baker
Vancouver, British Columbia
<http://gallery.me.com/alangbaker/100008/DSCF0162/web.jpg>

[Alan Baker]

In article >,
brian whatcott > wrote:

> Alan Baker wrote:
>
> >>>>>> I have never noticed the fabric lifting on my wings, however I have
> >>>>>> seen the fuel siphon out of a wing tank due to an improperly applied
> >>>>>> fuel cap.
> >>>>> And greater pressure in the tank than outside of it...
>
> /snip/
> >>> So, yes, the greater pressure inside the tank is pushing the fuel out.
> >>>
> >> Hmmm...it probably goes more like this: there's a 100 mph? wind past an
> >> open port, with some venturi effect certainly, but plenty of
> >> turbulence. If you beat up the surface with a gusty blow, it gets
> >> wavelets which can lap the filler and blow out the fuel.
>
> > How about it? It still doesn't change the physical reality that air
> > doesn't *pull* on the wings.
> >
>
>
> You're still singing the last hymn, Alan.
>
> We are now discussing how an open tank, with a 100 mph wind blowing over
> its top, can lose its fuel over the top. Do you think the tank has
> GREATER pressure due to the venturi effect of the airflow?

No. I think that the venturi effect lowers the pressure below the
pressure that already exists in the tank. Contrary to what the PP wrote,
a tank cannot be sealed if you are to pump fuel out of it. If it were
the pump would have to work against a rising pressure difference as it
removed fuel from the tank. Hence we know the tanks pressure must be
allowed to equalize.

If the pressure over an open filler is less than that in the tank -- and
assuming the filler is not simply pulling from the air/fuel vapor
mixture, then it will pull fuel from the tank if the pressure difference
is sufficient to lift the fuel the from its level in the tank to the
level of the open filler.

But it is being *pushed* out by higher pressure inside, not pulled.

--
Alan Baker
Vancouver, British Columbia
<http://gallery.me.com/alangbaker/100008/DSCF0162/web.jpg>

[Brian Whatcott]

Alan Baker wrote:
/snip/
>>>>> Any change in pressure is *by definition* a change in the number of
>>>>> particles in the fluid that are impacting the surface.

>>>> That assertion is incorrect. You are no dummy so I'm sure you'll correct
>>>> it when you realize the errors.

>>> Sorry, but it's not. Pressure is created by particle collisions.

>> Hmmm...looks like Jim expected too much from you: the kinetic theory of
>> gases has it that pressure may be computed from the temperature AND the
>> density of gases... that is to say, by retaining the SAME molar quantity
>> of gas, and raising its temperature (which translates to a higher
>> velocity), the pressure is increased P.V = R.t and all that....
>>
>> Put it another way: each "hotter" molecule reverses direction at a
>> surface with greater force.
>>
>> Brian W
>
> I'm perfectly aware of that...

It took me too long to realise the problem: you have a problem with
saying: "Oh yes, I got it worng."

People who WON'T do that in technical discussions qualify as people who
are just happy to stir up heated debate.

I am going to leave this thread now: wrasslin' with pigs gets the
hands jest too soiled...

Brian W

[Alan Baker]

In article >,
brian whatcott > wrote:

> Alan Baker wrote:
> /snip/
> >>>>> Any change in pressure is *by definition* a change in the number of
> >>>>> particles in the fluid that are impacting the surface.
>
> >>>> That assertion is incorrect. You are no dummy so I'm sure you'll correct
> >>>> it when you realize the errors.
>
> >>> Sorry, but it's not. Pressure is created by particle collisions.
>
> >> Hmmm...looks like Jim expected too much from you: the kinetic theory of
> >> gases has it that pressure may be computed from the temperature AND the
> >> density of gases... that is to say, by retaining the SAME molar quantity
> >> of gas, and raising its temperature (which translates to a higher
> >> velocity), the pressure is increased P.V = R.t and all that....
> >>
> >> Put it another way: each "hotter" molecule reverses direction at a
> >> surface with greater force.
> >>
> >> Brian W
> >
> > I'm perfectly aware of that...
>
> It took me too long to realise the problem: you have a problem with
> saying: "Oh yes, I got it worng."

I didn't get anything wrong.

I am and was perfectly aware of the fact that the temperature of a gas
indicates a different average speed for the gas molecules and thus a
different momentum when the strike a surface.

>
> People who WON'T do that in technical discussions qualify as people who
> are just happy to stir up heated debate.

I agree. What of it.

>
> I am going to leave this thread now: wrasslin' with pigs gets the
> hands jest too soiled...

You can go.

--
Alan Baker
Vancouver, British Columbia
<http://gallery.me.com/alangbaker/100008/DSCF0162/web.jpg>

[cavelamb[_2_]]

Alan Baker wrote:
> In article >,
> brian whatcott > wrote:
>
>> Alan Baker wrote:
>> /snip/
>>>>>>> Any change in pressure is *by definition* a change in the number of
>>>>>>> particles in the fluid that are impacting the surface.
>>>>>> That assertion is incorrect. You are no dummy so I'm sure you'll correct
>>>>>> it when you realize the errors.
>>>>> Sorry, but it's not. Pressure is created by particle collisions.
>>>> Hmmm...looks like Jim expected too much from you: the kinetic theory of
>>>> gases has it that pressure may be computed from the temperature AND the
>>>> density of gases... that is to say, by retaining the SAME molar quantity
>>>> of gas, and raising its temperature (which translates to a higher
>>>> velocity), the pressure is increased P.V = R.t and all that....
>>>>
>>>> Put it another way: each "hotter" molecule reverses direction at a
>>>> surface with greater force.
>>>>
>>>> Brian W
>>> I'm perfectly aware of that...
>> It took me too long to realise the problem: you have a problem with
>> saying: "Oh yes, I got it worng."
>
> I didn't get anything wrong.
>
> I am and was perfectly aware of the fact that the temperature of a gas
> indicates a different average speed for the gas molecules and thus a
> different momentum when the strike a surface.
>
>> People who WON'T do that in technical discussions qualify as people who
>> are just happy to stir up heated debate.
>
> I agree. What of it.
>
>> I am going to leave this thread now: wrasslin' with pigs gets the
>> hands jest too soiled...
>
> You can go.
>

I feel the same as Brian.
This had not been a discussion as much as a troll.

OF BLOODY COURSE, the high pressure area under the wing pushes up.
So what.

It couldn't possibly do that without the reduction of pressure on the top.
That's where all the magic is.

And you, sir, are a bloody bore.

So now, please also dismiss me.

[Alan Baker]

In article >,
cavelamb > wrote:

> Alan Baker wrote:
> > In article >,
> > brian whatcott > wrote:
> >
> >> Alan Baker wrote:
> >> /snip/
> >>>>>>> Any change in pressure is *by definition* a change in the number of
> >>>>>>> particles in the fluid that are impacting the surface.
> >>>>>> That assertion is incorrect. You are no dummy so I'm sure you'll
> >>>>>> correct
> >>>>>> it when you realize the errors.
> >>>>> Sorry, but it's not. Pressure is created by particle collisions.
> >>>> Hmmm...looks like Jim expected too much from you: the kinetic theory of
> >>>> gases has it that pressure may be computed from the temperature AND the
> >>>> density of gases... that is to say, by retaining the SAME molar quantity
> >>>> of gas, and raising its temperature (which translates to a higher
> >>>> velocity), the pressure is increased P.V = R.t and all that....
> >>>>
> >>>> Put it another way: each "hotter" molecule reverses direction at a
> >>>> surface with greater force.
> >>>>
> >>>> Brian W
> >>> I'm perfectly aware of that...
> >> It took me too long to realise the problem: you have a problem with
> >> saying: "Oh yes, I got it worng."
> >
> > I didn't get anything wrong.
> >
> > I am and was perfectly aware of the fact that the temperature of a gas
> > indicates a different average speed for the gas molecules and thus a
> > different momentum when the strike a surface.
> >
> >> People who WON'T do that in technical discussions qualify as people who
> >> are just happy to stir up heated debate.
> >
> > I agree. What of it.
> >
> >> I am going to leave this thread now: wrasslin' with pigs gets the
> >> hands jest too soiled...
> >
> > You can go.
> >
>
> I feel the same as Brian.
> This had not been a discussion as much as a troll.
>
> OF BLOODY COURSE, the high pressure area under the wing pushes up.
> So what.
>
> It couldn't possibly do that without the reduction of pressure on the top.
> That's where all the magic is.
>
> And you, sir, are a bloody bore.
>
> So now, please also dismiss me.

Look, I started out to clarify the point for those who have the wrong
perception of the situation...

....and it turned that there were such people.

I explicitly stated that if the OP meant that the low pressure above the
wing is responsible for two thirds of the pressure *difference* then he
was on solid ground (while allowing as how I didn't know what the
precise figures actually were).

Ever since then, types like you have been coming in and saying "IT
DOESN'T MATTER", when very clearly (because there are people who don't
understand the situation) it does.

It's like the downwash argument. You can say "IT DOESN'T MATTER", when
people argue that the air behind an aircraft is not deflected downward,
but it *does* matter. Having an accurate understanding of the physical
processes of flight matters.

--
Alan Baker
Vancouver, British Columbia
<http://gallery.me.com/alangbaker/100008/DSCF0162/web.jpg>

[Beryl[_3_]]

Alan Baker wrote:
>
> It's like the downwash argument. You can say "IT DOESN'T MATTER", when
> people argue that the air behind an aircraft is not deflected downward,
> but it *does* matter. Having an accurate understanding of the physical
> processes of flight matters.

It isn't really deflected downward, not for long anyway. It's churning
in a torus. Like a smoke ring.

[Alan Baker]

In article >,
Beryl > wrote:

> Alan Baker wrote:
> >
> > It's like the downwash argument. You can say "IT DOESN'T MATTER", when
> > people argue that the air behind an aircraft is not deflected downward,
> > but it *does* matter. Having an accurate understanding of the physical
> > processes of flight matters.
>
> It isn't really deflected downward, not for long anyway. It's churning
> in a torus. Like a smoke ring.

No.

It really *is* deflected downward.


The edges of the deflected area churn, and the air that is deflected
ends up getting diffused among all the other air below *it*, but it
really is deflected downward.

And eventually, that downward deflection makes it way until it -- very
diffusely -- impacts upon the surface of the earth. That is the only
thing that finally stops it.

--
Alan Baker
Vancouver, British Columbia
<http://gallery.me.com/alangbaker/100008/DSCF0162/web.jpg>

[jan olieslagers[_2_]]

Alan Baker schreef:

> No.

Yawn.

[Beryl[_3_]]

Alan Baker wrote:
> In article >,
> Beryl > wrote:
>
>> Alan Baker wrote:
>>> It's like the downwash argument. You can say "IT DOESN'T MATTER", when
>>> people argue that the air behind an aircraft is not deflected downward,
>>> but it *does* matter. Having an accurate understanding of the physical
>>> processes of flight matters.
>> It isn't really deflected downward, not for long anyway. It's churning
>> in a torus. Like a smoke ring.
>
> No.
>
> It really *is* deflected downward.
>
>
> The edges of the deflected area churn, and the air that is deflected
> ends up getting diffused among all the other air below *it*, but it
> really is deflected downward.
>
> And eventually, that downward deflection makes it way until it -- very
> diffusely -- impacts upon the surface of the earth. That is the only
> thing that finally stops it.

After more than 100 years of flight, the atmosphere still hasn't been
pushed down to the earth's surface.

[cavelamb[_2_]]

Ok, so there is a low pressure field above the wing,
and the wing is pressed up from underneath.

So, just out of curiosity, what happens to the air
that was in the low pressure field above the wing -
after the wing passes?

Does it just magically co back to it's old ways
(and places)?

And the air that was in the high pressure field under
the wing?

After the wing passes, is it unaffected as well?

[Beryl[_3_]]

cavelamb wrote:
> Ok, so there is a low pressure field above the wing,
> and the wing is pressed up from underneath.
>
> So, just out of curiosity, what happens to the air
> that was in the low pressure field above the wing -
> after the wing passes?
>
> Does it just magically co back to it's old ways
> (and places)?
>
> And the air that was in the high pressure field under
> the wing?
>
> After the wing passes, is it unaffected as well?

It's all a slowly descending smoke ring. If the earth was "the only
thing that finally stops it" as Alan says, none of the ring's energy
would be lost as it pushes through the surrounding air to reach the earth.

<http://www.av8n.com/how/htm/airfoils.html#sec-circulation-vortices>
Figure 3.27 ties the wingtip vortices in with the rest of the
circulation pattern, showing the whole smoke ring in red.

Also look up at section Section 3.11,
<http://www.av8n.com/how/htm/airfoils.html#sec-spinners>
Add the Fluttering Card circulation, Figure 3.25, to familiar tip
vortices, and you get the whole ring.

Other articles do a nice job explaining tip vortices or downwash behind
the wing as isolated subjects, but that's where they end their stories.

[Jim Logajan]

Alan Baker > wrote:
> Jim Logajan > wrote:
>> Alan Baker > wrote:
>> > Any change in pressure is *by definition* a change in the number of
>> > particles in the fluid that are impacting the surface.
>>
>> That assertion is incorrect. You are no dummy so I'm sure you'll
>> correct it when you realize the errors.
>
> Sorry, but it's not. Pressure is created by particle collisions.

Brian Whatcott already addressed one of the errors I had in mind. The other
I had in mind was your incorrect assertion "*by definition*". You should
have asserted "*by derivation*". College level texts on statistical and
thermal physics *derive* the gas laws from statistical mechanics; they do
not present them as true "by definition." (Though that would make for short
textbooks!)

[Jim Logajan]

Alan Baker > wrote:
> In article >,
> Beryl > wrote:
>
>> Alan Baker wrote:
>> >
>> > It's like the downwash argument. You can say "IT DOESN'T MATTER",
>> > when people argue that the air behind an aircraft is not deflected
>> > downward, but it *does* matter. Having an accurate understanding of
>> > the physical processes of flight matters.
>>
>> It isn't really deflected downward, not for long anyway. It's
>> churning in a torus. Like a smoke ring.
>
> No.
>
> It really *is* deflected downward.

It's also deflected upward. ;-)

Here's why:
Because the airplane and the Earth have zero relative vertical velocity
during straight and level flight, conservation of momentum requires the
net vertical flow of air to also be zero.

Therefore in subsonic flows where the fluid is assumed incompressible, to
the extent any fluid is moving downward, conservation of mass requires an
equal amount of mass must be moving upward (the continuity requirement.)

Hence airplanes must cause air to move in circles.

> The edges of the deflected area churn, and the air that is deflected
> ends up getting diffused among all the other air below *it*, but it
> really is deflected downward.

Yes some deflection downward occurs. But I don't know that it could be
said to "diffuse" in any sense due to conservation of mass and momentum
requirements.

> And eventually, that downward deflection makes it way until it -- very
> diffusely -- impacts upon the surface of the earth. That is the only
> thing that finally stops it.

That assertion is not true in general. What appears to happen instead is
that any downward deflection is quickly reversed, leading to what is
known as a shed vortex. Here are some links on the subject:

http://www.grc.nasa.gov/WWW/K-12/airplane/shed.html
http://www.grc.nasa.gov/WWW/K-12/airplane/downwash.html

While the deflected flow doesn't need to reach the surface of the earth
for the airplane to stay aloft, an increase in air _pressure_ would
eventually make its way to the surface.

[cavelamb[_2_]]

Beryl wrote:
> cavelamb wrote:
>> Ok, so there is a low pressure field above the wing,
>> and the wing is pressed up from underneath.
>>
>> So, just out of curiosity, what happens to the air
>> that was in the low pressure field above the wing -
>> after the wing passes?
>>
>> Does it just magically co back to it's old ways
>> (and places)?
>>
>> And the air that was in the high pressure field under
>> the wing?
>>
>> After the wing passes, is it unaffected as well?
>
> It's all a slowly descending smoke ring. If the earth was "the only
> thing that finally stops it" as Alan says, none of the ring's energy
> would be lost as it pushes through the surrounding air to reach the earth.
>
> <http://www.av8n.com/how/htm/airfoils.html#sec-circulation-vortices>
> Figure 3.27 ties the wingtip vortices in with the rest of the
> circulation pattern, showing the whole smoke ring in red.
>
> Also look up at section Section 3.11,
> <http://www.av8n.com/how/htm/airfoils.html#sec-spinners>
> Add the Fluttering Card circulation, Figure 3.25, to familiar tip
> vortices, and you get the whole ring.
>
> Other articles do a nice job explaining tip vortices or downwash behind
> the wing as isolated subjects, but that's where they end their stories.


I've seen the results first hand.

Flying along just above a smooth cloud surface at high subsonic,
the "wake" behind the leader makes a shallow trough in the cloud,
then the edges swirl back up into the tip vortices.

The high pressure air underneath rebounds up, and the low pressure
field above the wing rebounds back down.

Net result = zero.

[Alan Baker]

In article >,
Beryl > wrote:

> Alan Baker wrote:
> > In article >,
> > Beryl > wrote:
> >
> >> Alan Baker wrote:
> >>> It's like the downwash argument. You can say "IT DOESN'T MATTER", when
> >>> people argue that the air behind an aircraft is not deflected downward,
> >>> but it *does* matter. Having an accurate understanding of the physical
> >>> processes of flight matters.
> >> It isn't really deflected downward, not for long anyway. It's churning
> >> in a torus. Like a smoke ring.
> >
> > No.
> >
> > It really *is* deflected downward.
> >
> >
> > The edges of the deflected area churn, and the air that is deflected
> > ends up getting diffused among all the other air below *it*, but it
> > really is deflected downward.
> >
> > And eventually, that downward deflection makes it way until it -- very
> > diffusely -- impacts upon the surface of the earth. That is the only
> > thing that finally stops it.
>
> After more than 100 years of flight, the atmosphere still hasn't been
> pushed down to the earth's surface.

Sorry, Beryl, but you're just wrong.

--
Alan Baker
Vancouver, British Columbia
<http://gallery.me.com/alangbaker/100008/DSCF0162/web.jpg>

[Alan Baker]

In article >,
cavelamb > wrote:

> Beryl wrote:
> > cavelamb wrote:
> >> Ok, so there is a low pressure field above the wing,
> >> and the wing is pressed up from underneath.
> >>
> >> So, just out of curiosity, what happens to the air
> >> that was in the low pressure field above the wing -
> >> after the wing passes?
> >>
> >> Does it just magically co back to it's old ways
> >> (and places)?
> >>
> >> And the air that was in the high pressure field under
> >> the wing?
> >>
> >> After the wing passes, is it unaffected as well?
> >
> > It's all a slowly descending smoke ring. If the earth was "the only
> > thing that finally stops it" as Alan says, none of the ring's energy
> > would be lost as it pushes through the surrounding air to reach the earth.
> >
> > <http://www.av8n.com/how/htm/airfoils.html#sec-circulation-vortices>
> > Figure 3.27 ties the wingtip vortices in with the rest of the
> > circulation pattern, showing the whole smoke ring in red.
> >
> > Also look up at section Section 3.11,
> > <http://www.av8n.com/how/htm/airfoils.html#sec-spinners>
> > Add the Fluttering Card circulation, Figure 3.25, to familiar tip
> > vortices, and you get the whole ring.
> >
> > Other articles do a nice job explaining tip vortices or downwash behind
> > the wing as isolated subjects, but that's where they end their stories.
>
>
> I've seen the results first hand.
>
> Flying along just above a smooth cloud surface at high subsonic,
> the "wake" behind the leader makes a shallow trough in the cloud,
> then the edges swirl back up into the tip vortices.
>
> The high pressure air underneath rebounds up, and the low pressure
> field above the wing rebounds back down.
>
> Net result = zero.

Sorry, but wrong.

--
Alan Baker
Vancouver, British Columbia
<http://gallery.me.com/alangbaker/100008/DSCF0162/web.jpg>

[Alan Baker]

In article >,
Jim Logajan > wrote:

> Alan Baker > wrote:
> > In article >,
> > Beryl > wrote:
> >
> >> Alan Baker wrote:
> >> >
> >> > It's like the downwash argument. You can say "IT DOESN'T MATTER",
> >> > when people argue that the air behind an aircraft is not deflected
> >> > downward, but it *does* matter. Having an accurate understanding of
> >> > the physical processes of flight matters.
> >>
> >> It isn't really deflected downward, not for long anyway. It's
> >> churning in a torus. Like a smoke ring.
> >
> > No.
> >
> > It really *is* deflected downward.
>
> It's also deflected upward. ;-)
>
> Here's why:
> Because the airplane and the Earth have zero relative vertical velocity
> during straight and level flight, conservation of momentum requires the
> net vertical flow of air to also be zero.
>
> Therefore in subsonic flows where the fluid is assumed incompressible, to
> the extent any fluid is moving downward, conservation of mass requires an
> equal amount of mass must be moving upward (the continuity requirement.)
>
> Hence airplanes must cause air to move in circles.

Nope. Wrong.

The aircraft is experience an force upward the entire time it is in
flight. That force means there must be an equal force acting on the air,
and since the air was not moving vertically (in our idealized case for
this discussion) before the aircraft arrived, the force exerted on it
must mean that it is moving downward afterward it has passed.

>
> > The edges of the deflected area churn, and the air that is deflected
> > ends up getting diffused among all the other air below *it*, but it
> > really is deflected downward.
>
> Yes some deflection downward occurs. But I don't know that it could be
> said to "diffuse" in any sense due to conservation of mass and momentum
> requirements.

As the air the plane has forced downward encounters more air, the
momentum is diffused so that a greater and greater mass of air moves
downward at smaller and smaller velocities (net)...

....until it encounters the ground.

>
> > And eventually, that downward deflection makes it way until it -- very
> > diffusely -- impacts upon the surface of the earth. That is the only
> > thing that finally stops it.
>
> That assertion is not true in general. What appears to happen instead is
> that any downward deflection is quickly reversed, leading to what is
> known as a shed vortex. Here are some links on the subject:
>
> http://www.grc.nasa.gov/WWW/K-12/airplane/shed.html

Sorry, but the vortex is an edge effect. The net flow is downward.

> http://www.grc.nasa.gov/WWW/K-12/airplane/downwash.html
>
> While the deflected flow doesn't need to reach the surface of the earth
> for the airplane to stay aloft, an increase in air _pressure_ would
> eventually make its way to the surface.

--
Alan Baker
Vancouver, British Columbia
<http://gallery.me.com/alangbaker/100008/DSCF0162/web.jpg>

[Beryl[_3_]]

Alan Baker wrote:
> In article >,
> Beryl > wrote:
>
>> Alan Baker wrote:
>>> In article >,
>>> Beryl > wrote:
>>>
>>>> Alan Baker wrote:
>>>>> It's like the downwash argument. You can say "IT DOESN'T MATTER", when
>>>>> people argue that the air behind an aircraft is not deflected downward,
>>>>> but it *does* matter. Having an accurate understanding of the physical
>>>>> processes of flight matters.
>>>> It isn't really deflected downward, not for long anyway. It's churning
>>>> in a torus. Like a smoke ring.
>>> No.
>>>
>>> It really *is* deflected downward.
>>>
>>>
>>> The edges of the deflected area churn, and the air that is deflected
>>> ends up getting diffused among all the other air below *it*, but it
>>> really is deflected downward.
>>>
>>> And eventually, that downward deflection makes it way until it -- very
>>> diffusely -- impacts upon the surface of the earth. That is the only
>>> thing that finally stops it.
>> After more than 100 years of flight, the atmosphere still hasn't been
>> pushed down to the earth's surface.
>
> Sorry, Beryl, but you're just wrong.

As I said, the atmosphere isn't getting any shorter. Do you disagree
with that?
Repeating that "the net flow is downward" isn't making progress.

[Beryl[_3_]]

Alan Baker wrote:
...

> As the air the plane has forced downward encounters more air, the
> momentum is diffused so that a greater and greater mass of air moves
> downward at smaller and smaller velocities (net)...
>
> ...until it encounters the ground.

Yikes! Eventually, ALL of the air will be on the ground!

>>> And eventually, that downward deflection makes it way until it -- very
>>> diffusely -- impacts upon the surface of the earth. That is the only
>>> thing that finally stops it.
>> That assertion is not true in general. What appears to happen instead is
>> that any downward deflection is quickly reversed, leading to what is
>> known as a shed vortex. Here are some links on the subject:
>>
>> http://www.grc.nasa.gov/WWW/K-12/airplane/shed.html
>
> Sorry, but the vortex is an edge effect. The net flow is downward.

Mankind needs to set up fans IMMEDIATELY to move air back up into the sky!

[Alan Baker]

In article >,
Beryl > wrote:

> Alan Baker wrote:
> > In article >,
> > Beryl > wrote:
> >
> >> Alan Baker wrote:
> >>> In article >,
> >>> Beryl > wrote:
> >>>
> >>>> Alan Baker wrote:
> >>>>> It's like the downwash argument. You can say "IT DOESN'T MATTER", when
> >>>>> people argue that the air behind an aircraft is not deflected downward,
> >>>>> but it *does* matter. Having an accurate understanding of the physical
> >>>>> processes of flight matters.
> >>>> It isn't really deflected downward, not for long anyway. It's churning
> >>>> in a torus. Like a smoke ring.
> >>> No.
> >>>
> >>> It really *is* deflected downward.
> >>>
> >>>
> >>> The edges of the deflected area churn, and the air that is deflected
> >>> ends up getting diffused among all the other air below *it*, but it
> >>> really is deflected downward.
> >>>
> >>> And eventually, that downward deflection makes it way until it -- very
> >>> diffusely -- impacts upon the surface of the earth. That is the only
> >>> thing that finally stops it.
> >> After more than 100 years of flight, the atmosphere still hasn't been
> >> pushed down to the earth's surface.
> >
> > Sorry, Beryl, but you're just wrong.
>
> As I said, the atmosphere isn't getting any shorter. Do you disagree
> with that?
> Repeating that "the net flow is downward" isn't making progress.

The net flow is downward until it hits the ground and the momentum is
transfer to the earth.

--
Alan Baker
Vancouver, British Columbia
<http://gallery.me.com/alangbaker/100008/DSCF0162/web.jpg>

[Beryl[_3_]]

Alan Baker wrote:
> Beryl > wrote:
>> Alan Baker wrote:
>>> Beryl > wrote:
>>>> Alan Baker wrote:
>>>>> Beryl > wrote:
>>>>>> Alan Baker wrote:
>
>>>>>>> It's like the downwash argument. You can say "IT DOESN'T
>>>>>>> MATTER", when people argue that the air behind an
>>>>>>> aircraft is not deflected downward, but it *does* matter.
>>>>>>> Having an accurate understanding of the physical
>>>>>>> processes of flight matters.
>>>>>> It isn't really deflected downward, not for long anyway.
>>>>>> It's churning in a torus. Like a smoke ring.
>>>>>
>>>>> No.
>>>>>
>>>>> It really *is* deflected downward.
>>>>>
>>>>> The edges of the deflected area churn, and the air that is
>>>>> deflected ends up getting diffused among all the other air
>>>>> below *it*, but it really is deflected downward.
>>>>>
>>>>> And eventually, that downward deflection makes it way until
>>>>> it -- very diffusely -- impacts upon the surface of the
>>>>> earth. That is the only thing that finally stops it.
>>>>>
>>>> After more than 100 years of flight, the atmosphere still
>>>> hasn't been pushed down to the earth's surface.
>>>>
>>> Sorry, Beryl, but you're just wrong.
>>>
>> As I said, the atmosphere isn't getting any shorter. Do you
>> disagree with that? Repeating that "the net flow is downward" isn't
>> making progress.
>
> The net flow is downward until it hits the ground and the momentum is
> transfer to the earth.

Has to be an equal upward flow. Somewhere. Where?

Imagine riding in a C-130 Hercules. You're flying an RC model airplane
in the cabin! (That's why I picked a C-130)
The model's weight is applied to the cabin floor, of course, but the
"downwash" from the model's wing doesn't pile up on the floor.

http://www.efluids.com/efluids/gallery/gallery_pages/Morris_4.jsp
The column of downward flow in the center doesn't really flow down so
far, does it?

[Alan Baker]

In article >,
Beryl > wrote:

> Alan Baker wrote:
> > Beryl > wrote:
> >> Alan Baker wrote:
> >>> Beryl > wrote:
> >>>> Alan Baker wrote:
> >>>>> Beryl > wrote:
> >>>>>> Alan Baker wrote:
> >
> >>>>>>> It's like the downwash argument. You can say "IT DOESN'T
> >>>>>>> MATTER", when people argue that the air behind an
> >>>>>>> aircraft is not deflected downward, but it *does* matter.
> >>>>>>> Having an accurate understanding of the physical
> >>>>>>> processes of flight matters.
> >>>>>> It isn't really deflected downward, not for long anyway.
> >>>>>> It's churning in a torus. Like a smoke ring.
> >>>>>
> >>>>> No.
> >>>>>
> >>>>> It really *is* deflected downward.
> >>>>>
> >>>>> The edges of the deflected area churn, and the air that is
> >>>>> deflected ends up getting diffused among all the other air
> >>>>> below *it*, but it really is deflected downward.
> >>>>>
> >>>>> And eventually, that downward deflection makes it way until
> >>>>> it -- very diffusely -- impacts upon the surface of the
> >>>>> earth. That is the only thing that finally stops it.
> >>>>>
> >>>> After more than 100 years of flight, the atmosphere still
> >>>> hasn't been pushed down to the earth's surface.
> >>>>
> >>> Sorry, Beryl, but you're just wrong.
> >>>
> >> As I said, the atmosphere isn't getting any shorter. Do you
> >> disagree with that? Repeating that "the net flow is downward" isn't
> >> making progress.
> >
> > The net flow is downward until it hits the ground and the momentum is
> > transfer to the earth.
>
> Has to be an equal upward flow. Somewhere. Where?
>
> Imagine riding in a C-130 Hercules. You're flying an RC model airplane
> in the cabin! (That's why I picked a C-130)
> The model's weight is applied to the cabin floor, of course, but the
> "downwash" from the model's wing doesn't pile up on the floor.
>
> http://www.efluids.com/efluids/gallery/gallery_pages/Morris_4.jsp
> The column of downward flow in the center doesn't really flow down so
> far, does it?

Yes, it does.

All the way to the ground.

Spread out among lots and lots of air, but that's where the momentum
*has* to go.

--
Alan Baker
Vancouver, British Columbia
<http://gallery.me.com/alangbaker/100008/DSCF0162/web.jpg>

[Beryl[_3_]]

Alan Baker wrote:
> In article >,
> Beryl > wrote:
>
>> Alan Baker wrote:
>>> Beryl > wrote:
>>>> Alan Baker wrote:
>>>>> Beryl > wrote:
>>>>>> Alan Baker wrote:
>>>>>>> Beryl > wrote:
>>>>>>>> Alan Baker wrote:
>>>>>>>>> It's like the downwash argument. You can say "IT DOESN'T
>>>>>>>>> MATTER", when people argue that the air behind an
>>>>>>>>> aircraft is not deflected downward, but it *does* matter.
>>>>>>>>> Having an accurate understanding of the physical
>>>>>>>>> processes of flight matters.
>>>>>>>> It isn't really deflected downward, not for long anyway.
>>>>>>>> It's churning in a torus. Like a smoke ring.
>>>>>>> No.
>>>>>>>
>>>>>>> It really *is* deflected downward.
>>>>>>>
>>>>>>> The edges of the deflected area churn, and the air that is
>>>>>>> deflected ends up getting diffused among all the other air
>>>>>>> below *it*, but it really is deflected downward.
>>>>>>>
>>>>>>> And eventually, that downward deflection makes it way until
>>>>>>> it -- very diffusely -- impacts upon the surface of the
>>>>>>> earth. That is the only thing that finally stops it.
>>>>>>>
>>>>>> After more than 100 years of flight, the atmosphere still
>>>>>> hasn't been pushed down to the earth's surface.
>>>>>>
>>>>> Sorry, Beryl, but you're just wrong.
>>>>>
>>>> As I said, the atmosphere isn't getting any shorter. Do you
>>>> disagree with that? Repeating that "the net flow is downward" isn't
>>>> making progress.
>>> The net flow is downward until it hits the ground and the momentum is
>>> transfer to the earth.
>> Has to be an equal upward flow. Somewhere. Where?
>>
>> Imagine riding in a C-130 Hercules. You're flying an RC model airplane
>> in the cabin! (That's why I picked a C-130)
>> The model's weight is applied to the cabin floor, of course, but the
>> "downwash" from the model's wing doesn't pile up on the floor.
>>
>> http://www.efluids.com/efluids/gallery/gallery_pages/Morris_4.jsp
>> The column of downward flow in the center doesn't really flow down so
>> far, does it?
>
> Yes, it does.
>
> All the way to the ground.
>
> Spread out among lots and lots of air, but that's where the momentum
> *has* to go.

Say where the _air_ has to go.

[cavelamb[_2_]]

Beryl wrote:
> Alan Baker wrote:
>> In article >,
>> Beryl > wrote:
>>
>>> Alan Baker wrote:
>>>> Beryl > wrote:
>>>>> Alan Baker wrote:
>>>>>> Beryl > wrote:
>>>>>>> Alan Baker wrote:
>>>>>>>> Beryl > wrote:
>>>>>>>>> Alan Baker wrote:
>>>>>>>>>> It's like the downwash argument. You can say "IT DOESN'T
>>>>>>>>>> MATTER", when people argue that the air behind an
>>>>>>>>>> aircraft is not deflected downward, but it *does* matter.
>>>>>>>>>> Having an accurate understanding of the physical processes of
>>>>>>>>>> flight matters.
>>>>>>>>> It isn't really deflected downward, not for long anyway.
>>>>>>>>> It's churning in a torus. Like a smoke ring.
>>>>>>>> No.
>>>>>>>>
>>>>>>>> It really *is* deflected downward.
>>>>>>>>
>>>>>>>> The edges of the deflected area churn, and the air that is
>>>>>>>> deflected ends up getting diffused among all the other air
>>>>>>>> below *it*, but it really is deflected downward.
>>>>>>>>
>>>>>>>> And eventually, that downward deflection makes it way until
>>>>>>>> it -- very diffusely -- impacts upon the surface of the
>>>>>>>> earth. That is the only thing that finally stops it.
>>>>>>>>
>>>>>>> After more than 100 years of flight, the atmosphere still
>>>>>>> hasn't been pushed down to the earth's surface.
>>>>>>>
>>>>>> Sorry, Beryl, but you're just wrong.
>>>>>>
>>>>> As I said, the atmosphere isn't getting any shorter. Do you
>>>>> disagree with that? Repeating that "the net flow is downward" isn't
>>>>> making progress.
>>>> The net flow is downward until it hits the ground and the momentum is
>>>> transfer to the earth.
>>> Has to be an equal upward flow. Somewhere. Where?
>>>
>>> Imagine riding in a C-130 Hercules. You're flying an RC model
>>> airplane in the cabin! (That's why I picked a C-130)
>>> The model's weight is applied to the cabin floor, of course, but the
>>> "downwash" from the model's wing doesn't pile up on the floor.
>>>
>>> http://www.efluids.com/efluids/gallery/gallery_pages/Morris_4.jsp
>>> The column of downward flow in the center doesn't really flow down so
>>> far, does it?
>>
>> Yes, it does.
>>
>> All the way to the ground.
>> Spread out among lots and lots of air, but that's where the momentum
>> *has* to go.
>
> Say where the _air_ has to go.


Please!

I think maybe we are talking about very different things.

I'm talking flow.

[Alan Baker]

In article >,
Beryl > wrote:

> Alan Baker wrote:
> > In article >,
> > Beryl > wrote:
> >
> >> Alan Baker wrote:
> >>> Beryl > wrote:
> >>>> Alan Baker wrote:
> >>>>> Beryl > wrote:
> >>>>>> Alan Baker wrote:
> >>>>>>> Beryl > wrote:
> >>>>>>>> Alan Baker wrote:
> >>>>>>>>> It's like the downwash argument. You can say "IT DOESN'T
> >>>>>>>>> MATTER", when people argue that the air behind an
> >>>>>>>>> aircraft is not deflected downward, but it *does* matter.
> >>>>>>>>> Having an accurate understanding of the physical
> >>>>>>>>> processes of flight matters.
> >>>>>>>> It isn't really deflected downward, not for long anyway.
> >>>>>>>> It's churning in a torus. Like a smoke ring.
> >>>>>>> No.
> >>>>>>>
> >>>>>>> It really *is* deflected downward.
> >>>>>>>
> >>>>>>> The edges of the deflected area churn, and the air that is
> >>>>>>> deflected ends up getting diffused among all the other air
> >>>>>>> below *it*, but it really is deflected downward.
> >>>>>>>
> >>>>>>> And eventually, that downward deflection makes it way until
> >>>>>>> it -- very diffusely -- impacts upon the surface of the
> >>>>>>> earth. That is the only thing that finally stops it.
> >>>>>>>
> >>>>>> After more than 100 years of flight, the atmosphere still
> >>>>>> hasn't been pushed down to the earth's surface.
> >>>>>>
> >>>>> Sorry, Beryl, but you're just wrong.
> >>>>>
> >>>> As I said, the atmosphere isn't getting any shorter. Do you
> >>>> disagree with that? Repeating that "the net flow is downward" isn't
> >>>> making progress.
> >>> The net flow is downward until it hits the ground and the momentum is
> >>> transfer to the earth.
> >> Has to be an equal upward flow. Somewhere. Where?
> >>
> >> Imagine riding in a C-130 Hercules. You're flying an RC model airplane
> >> in the cabin! (That's why I picked a C-130)
> >> The model's weight is applied to the cabin floor, of course, but the
> >> "downwash" from the model's wing doesn't pile up on the floor.
> >>
> >> http://www.efluids.com/efluids/gallery/gallery_pages/Morris_4.jsp
> >> The column of downward flow in the center doesn't really flow down so
> >> far, does it?
> >
> > Yes, it does.
> >
> > All the way to the ground.
> >
> > Spread out among lots and lots of air, but that's where the momentum
> > *has* to go.
>
> Say where the _air_ has to go.

The aircraft starts the air moving downward. Net downward momentum.

The ground stops that net downward motion.

--
Alan Baker
Vancouver, British Columbia
<http://gallery.me.com/alangbaker/100008/DSCF0162/web.jpg>

[cavelamb[_2_]]

On second thought, no, I don't want to get sucked back into this troll.

[Beryl[_3_]]

Alan Baker wrote:
> In article >,
> Beryl > wrote:
>
>> Alan Baker wrote:
>>> In article >,
>>> Beryl > wrote:
>>>
>>>> Alan Baker wrote:
>>>>> Beryl > wrote:
>>>>>> Alan Baker wrote:
>>>>>>> Beryl > wrote:
>>>>>>>> Alan Baker wrote:
>>>>>>>>> Beryl > wrote:
>>>>>>>>>> Alan Baker wrote:
>>>>>>>>>>> It's like the downwash argument. You can say "IT DOESN'T
>>>>>>>>>>> MATTER", when people argue that the air behind an
>>>>>>>>>>> aircraft is not deflected downward, but it *does* matter.
>>>>>>>>>>> Having an accurate understanding of the physical
>>>>>>>>>>> processes of flight matters.
>>>>>>>>>> It isn't really deflected downward, not for long anyway.
>>>>>>>>>> It's churning in a torus. Like a smoke ring.
>>>>>>>>> No.
>>>>>>>>>
>>>>>>>>> It really *is* deflected downward.
>>>>>>>>>
>>>>>>>>> The edges of the deflected area churn, and the air that is
>>>>>>>>> deflected ends up getting diffused among all the other air
>>>>>>>>> below *it*, but it really is deflected downward.
>>>>>>>>>
>>>>>>>>> And eventually, that downward deflection makes it way until
>>>>>>>>> it -- very diffusely -- impacts upon the surface of the
>>>>>>>>> earth. That is the only thing that finally stops it.
>>>>>>>>>
>>>>>>>> After more than 100 years of flight, the atmosphere still
>>>>>>>> hasn't been pushed down to the earth's surface.
>>>>>>>>
>>>>>>> Sorry, Beryl, but you're just wrong.
>>>>>>>
>>>>>> As I said, the atmosphere isn't getting any shorter. Do you
>>>>>> disagree with that? Repeating that "the net flow is downward" isn't
>>>>>> making progress.
>>>>> The net flow is downward until it hits the ground and the momentum is
>>>>> transfer to the earth.
>>>> Has to be an equal upward flow. Somewhere. Where?
>>>>
>>>> Imagine riding in a C-130 Hercules. You're flying an RC model airplane
>>>> in the cabin! (That's why I picked a C-130)
>>>> The model's weight is applied to the cabin floor, of course, but the
>>>> "downwash" from the model's wing doesn't pile up on the floor.
>>>>
>>>> http://www.efluids.com/efluids/gallery/gallery_pages/Morris_4.jsp
>>>> The column of downward flow in the center doesn't really flow down so
>>>> far, does it?
>>> Yes, it does.
>>>
>>> All the way to the ground.
>>>
>>> Spread out among lots and lots of air, but that's where the momentum
>>> *has* to go.
>> Say where the _air_ has to go.
>
> The aircraft starts the air moving downward. Net downward momentum.
>
> The ground stops that net downward motion.

What if there were no ground? Jupiter has atmosphere, gravity, and I
don't see why a solid surface below is required for flight.

[Alan Baker]

In article >,
Beryl > wrote:

> Alan Baker wrote:
> > In article >,
> > Beryl > wrote:
> >
> >> Alan Baker wrote:
> >>> In article >,
> >>> Beryl > wrote:
> >>>
> >>>> Alan Baker wrote:
> >>>>> Beryl > wrote:
> >>>>>> Alan Baker wrote:
> >>>>>>> Beryl > wrote:
> >>>>>>>> Alan Baker wrote:
> >>>>>>>>> Beryl > wrote:
> >>>>>>>>>> Alan Baker wrote:
> >>>>>>>>>>> It's like the downwash argument. You can say "IT DOESN'T
> >>>>>>>>>>> MATTER", when people argue that the air behind an
> >>>>>>>>>>> aircraft is not deflected downward, but it *does* matter.
> >>>>>>>>>>> Having an accurate understanding of the physical
> >>>>>>>>>>> processes of flight matters.
> >>>>>>>>>> It isn't really deflected downward, not for long anyway.
> >>>>>>>>>> It's churning in a torus. Like a smoke ring.
> >>>>>>>>> No.
> >>>>>>>>>
> >>>>>>>>> It really *is* deflected downward.
> >>>>>>>>>
> >>>>>>>>> The edges of the deflected area churn, and the air that is
> >>>>>>>>> deflected ends up getting diffused among all the other air
> >>>>>>>>> below *it*, but it really is deflected downward.
> >>>>>>>>>
> >>>>>>>>> And eventually, that downward deflection makes it way until
> >>>>>>>>> it -- very diffusely -- impacts upon the surface of the
> >>>>>>>>> earth. That is the only thing that finally stops it.
> >>>>>>>>>
> >>>>>>>> After more than 100 years of flight, the atmosphere still
> >>>>>>>> hasn't been pushed down to the earth's surface.
> >>>>>>>>
> >>>>>>> Sorry, Beryl, but you're just wrong.
> >>>>>>>
> >>>>>> As I said, the atmosphere isn't getting any shorter. Do you
> >>>>>> disagree with that? Repeating that "the net flow is downward" isn't
> >>>>>> making progress.
> >>>>> The net flow is downward until it hits the ground and the momentum is
> >>>>> transfer to the earth.
> >>>> Has to be an equal upward flow. Somewhere. Where?
> >>>>
> >>>> Imagine riding in a C-130 Hercules. You're flying an RC model airplane
> >>>> in the cabin! (That's why I picked a C-130)
> >>>> The model's weight is applied to the cabin floor, of course, but the
> >>>> "downwash" from the model's wing doesn't pile up on the floor.
> >>>>
> >>>> http://www.efluids.com/efluids/gallery/gallery_pages/Morris_4.jsp
> >>>> The column of downward flow in the center doesn't really flow down so
> >>>> far, does it?
> >>> Yes, it does.
> >>>
> >>> All the way to the ground.
> >>>
> >>> Spread out among lots and lots of air, but that's where the momentum
> >>> *has* to go.
> >> Say where the _air_ has to go.
> >
> > The aircraft starts the air moving downward. Net downward momentum.
> >
> > The ground stops that net downward motion.
>
> What if there were no ground? Jupiter has atmosphere, gravity, and I
> don't see why a solid surface below is required for flight.

Look, the aircraft imparts downward momentum to the air. If only air is
encountered by that air, the momentum cannot be go away, so it keeps
moving downward. As more air shares the momentum, it moves more slowly,
but it still moves until eventually, the air encounters the Earth.

There, the momentum it imparts downward to the earth is match by the
momentum imparted upward by the force of gravity that the aircraft
exerts on the earth; balancing out the system.

On Earth, the gravity of the planet far outweighs the gravity of our
atmosphere and thus essentially all the momentum of the moving
atmosphere must reach the ground to react out, but on Jupiter it's all
atmosphere and so eventually gravity acting on that atmosphere reacts
out the momentum.

--
Alan Baker
Vancouver, British Columbia
<http://gallery.me.com/alangbaker/100008/DSCF0162/web.jpg>

[Beryl[_3_]]

Alan Baker wrote:
> In article >,
> Beryl > wrote:
>
>> Alan Baker wrote:
>>> In article >,
>>> Beryl > wrote:
>>>
>>>> Alan Baker wrote:
>>>>> In article >,
>>>>> Beryl > wrote:
>>>>>
>>>>>> Alan Baker wrote:
>>>>>>> Beryl > wrote:
>>>>>>>> Alan Baker wrote:
>>>>>>>>> Beryl > wrote:
>>>>>>>>>> Alan Baker wrote:
>>>>>>>>>>> Beryl > wrote:
>>>>>>>>>>>> Alan Baker wrote:
>>>>>>>>>>>>> It's like the downwash argument. You can say "IT DOESN'T
>>>>>>>>>>>>> MATTER", when people argue that the air behind an
>>>>>>>>>>>>> aircraft is not deflected downward, but it *does* matter.
>>>>>>>>>>>>> Having an accurate understanding of the physical
>>>>>>>>>>>>> processes of flight matters.
>>>>>>>>>>>> It isn't really deflected downward, not for long anyway.
>>>>>>>>>>>> It's churning in a torus. Like a smoke ring.
>>>>>>>>>>> No.
>>>>>>>>>>>
>>>>>>>>>>> It really *is* deflected downward.
>>>>>>>>>>>
>>>>>>>>>>> The edges of the deflected area churn, and the air that is
>>>>>>>>>>> deflected ends up getting diffused among all the other air
>>>>>>>>>>> below *it*, but it really is deflected downward.
>>>>>>>>>>>
>>>>>>>>>>> And eventually, that downward deflection makes it way until
>>>>>>>>>>> it -- very diffusely -- impacts upon the surface of the
>>>>>>>>>>> earth. That is the only thing that finally stops it.
>>>>>>>>>>>
>>>>>>>>>> After more than 100 years of flight, the atmosphere still
>>>>>>>>>> hasn't been pushed down to the earth's surface.
>>>>>>>>>>
>>>>>>>>> Sorry, Beryl, but you're just wrong.
>>>>>>>>>
>>>>>>>> As I said, the atmosphere isn't getting any shorter. Do you
>>>>>>>> disagree with that? Repeating that "the net flow is downward" isn't
>>>>>>>> making progress.
>>>>>>> The net flow is downward until it hits the ground and the momentum is
>>>>>>> transfer to the earth.
>>>>>> Has to be an equal upward flow. Somewhere. Where?
>>>>>>
>>>>>> Imagine riding in a C-130 Hercules. You're flying an RC model airplane
>>>>>> in the cabin! (That's why I picked a C-130)
>>>>>> The model's weight is applied to the cabin floor, of course, but the
>>>>>> "downwash" from the model's wing doesn't pile up on the floor.
>>>>>>
>>>>>> http://www.efluids.com/efluids/gallery/gallery_pages/Morris_4.jsp
>>>>>> The column of downward flow in the center doesn't really flow down so
>>>>>> far, does it?
>>>>> Yes, it does.
>>>>>
>>>>> All the way to the ground.
>>>>>
>>>>> Spread out among lots and lots of air, but that's where the momentum
>>>>> *has* to go.
>>>> Say where the _air_ has to go.
>>> The aircraft starts the air moving downward. Net downward momentum.
>>>
>>> The ground stops that net downward motion.
>> What if there were no ground? Jupiter has atmosphere, gravity, and I
>> don't see why a solid surface below is required for flight.
>
> Look, the aircraft imparts downward momentum to the air. If only air is
> encountered by that air, the momentum cannot be go away, so it keeps
> moving downward. As more air shares the momentum, it moves more slowly,
> but it still moves until eventually, the air encounters the Earth.
>
> There, the momentum it imparts downward to the earth is match by the
> momentum imparted upward by the force of gravity that the aircraft
> exerts on the earth; balancing out the system.
>
> On Earth, the gravity of the planet far outweighs the gravity of our
> atmosphere and thus essentially all the momentum of the moving
> atmosphere must reach the ground to react out, but on Jupiter it's all
> atmosphere and so eventually gravity acting on that atmosphere reacts
> out the momentum.

After an airplane lands, and the weight is on its wheels, a bunch of
compressed air jumps off the ground back up to the altitude where it
came from. Ready for re-use.

Let's talk about helicopters. We can replace that rotor with a squirrel
cage fan. Air is drawn down into the fan as before, and most of the
pressure differential is due to lowering pressure above the fan. As
before... except that now the air is exhausted out the periphery of the
centrifugal-flow squirrel cage fan, not down as it was with the old
axial-flow rotor. Will it fly? Where's the downwash?

[Alan Baker]

In article >,
Beryl > wrote:

> Alan Baker wrote:
> > In article >,
> > Beryl > wrote:
> >
> >> Alan Baker wrote:
> >>> In article >,
> >>> Beryl > wrote:
> >>>
> >>>> Alan Baker wrote:
> >>>>> In article >,
> >>>>> Beryl > wrote:
> >>>>>
> >>>>>> Alan Baker wrote:
> >>>>>>> Beryl > wrote:
> >>>>>>>> Alan Baker wrote:
> >>>>>>>>> Beryl > wrote:
> >>>>>>>>>> Alan Baker wrote:
> >>>>>>>>>>> Beryl > wrote:
> >>>>>>>>>>>> Alan Baker wrote:
> >>>>>>>>>>>>> It's like the downwash argument. You can say "IT DOESN'T
> >>>>>>>>>>>>> MATTER", when people argue that the air behind an
> >>>>>>>>>>>>> aircraft is not deflected downward, but it *does* matter.
> >>>>>>>>>>>>> Having an accurate understanding of the physical
> >>>>>>>>>>>>> processes of flight matters.
> >>>>>>>>>>>> It isn't really deflected downward, not for long anyway.
> >>>>>>>>>>>> It's churning in a torus. Like a smoke ring.
> >>>>>>>>>>> No.
> >>>>>>>>>>>
> >>>>>>>>>>> It really *is* deflected downward.
> >>>>>>>>>>>
> >>>>>>>>>>> The edges of the deflected area churn, and the air that is
> >>>>>>>>>>> deflected ends up getting diffused among all the other air
> >>>>>>>>>>> below *it*, but it really is deflected downward.
> >>>>>>>>>>>
> >>>>>>>>>>> And eventually, that downward deflection makes it way until
> >>>>>>>>>>> it -- very diffusely -- impacts upon the surface of the
> >>>>>>>>>>> earth. That is the only thing that finally stops it.
> >>>>>>>>>>>
> >>>>>>>>>> After more than 100 years of flight, the atmosphere still
> >>>>>>>>>> hasn't been pushed down to the earth's surface.
> >>>>>>>>>>
> >>>>>>>>> Sorry, Beryl, but you're just wrong.
> >>>>>>>>>
> >>>>>>>> As I said, the atmosphere isn't getting any shorter. Do you
> >>>>>>>> disagree with that? Repeating that "the net flow is downward" isn't
> >>>>>>>> making progress.
> >>>>>>> The net flow is downward until it hits the ground and the momentum is
> >>>>>>> transfer to the earth.
> >>>>>> Has to be an equal upward flow. Somewhere. Where?
> >>>>>>
> >>>>>> Imagine riding in a C-130 Hercules. You're flying an RC model airplane
> >>>>>> in the cabin! (That's why I picked a C-130)
> >>>>>> The model's weight is applied to the cabin floor, of course, but the
> >>>>>> "downwash" from the model's wing doesn't pile up on the floor.
> >>>>>>
> >>>>>> http://www.efluids.com/efluids/gallery/gallery_pages/Morris_4.jsp
> >>>>>> The column of downward flow in the center doesn't really flow down so
> >>>>>> far, does it?
> >>>>> Yes, it does.
> >>>>>
> >>>>> All the way to the ground.
> >>>>>
> >>>>> Spread out among lots and lots of air, but that's where the momentum
> >>>>> *has* to go.
> >>>> Say where the _air_ has to go.
> >>> The aircraft starts the air moving downward. Net downward momentum.
> >>>
> >>> The ground stops that net downward motion.
> >> What if there were no ground? Jupiter has atmosphere, gravity, and I
> >> don't see why a solid surface below is required for flight.
> >
> > Look, the aircraft imparts downward momentum to the air. If only air is
> > encountered by that air, the momentum cannot be go away, so it keeps
> > moving downward. As more air shares the momentum, it moves more slowly,
> > but it still moves until eventually, the air encounters the Earth.
> >
> > There, the momentum it imparts downward to the earth is match by the
> > momentum imparted upward by the force of gravity that the aircraft
> > exerts on the earth; balancing out the system.
> >
> > On Earth, the gravity of the planet far outweighs the gravity of our
> > atmosphere and thus essentially all the momentum of the moving
> > atmosphere must reach the ground to react out, but on Jupiter it's all
> > atmosphere and so eventually gravity acting on that atmosphere reacts
> > out the momentum.
>
> After an airplane lands, and the weight is on its wheels, a bunch of
> compressed air jumps off the ground back up to the altitude where it
> came from. Ready for re-use.

Nope.

>
> Let's talk about helicopters. We can replace that rotor with a squirrel
> cage fan. Air is drawn down into the fan as before, and most of the
> pressure differential is due to lowering pressure above the fan. As
> before... except that now the air is exhausted out the periphery of the
> centrifugal-flow squirrel cage fan, not down as it was with the old
> axial-flow rotor. Will it fly? Where's the downwash?

If there is no downwash, it will not fly. No.

See everyone: this is why understanding of the actual facts is required.

The for the aircraft to experience an upward force from the air (the
only thing in contact with it), it must exert a downward force on the
air. Because the air is not a rigid body in contact with the earth (the
source of the downward force of gravity on the aircraft), a force
applied to the air must -- M-U-S-T-! -- cause it to move downward. That
downward momentum must eventually be transferred to the source of the
downward force on the plane for the system to remain in equilibrium.

--
Alan Baker
Vancouver, British Columbia
<http://gallery.me.com/alangbaker/100008/DSCF0162/web.jpg>

[Jim Logajan]

Alan Baker > wrote:
> If there is no downwash, it will not fly. No.

You are arguing a point not under contention (at least with respect to
heavier-than-air aircraft.)

> See everyone: this is why understanding of the actual facts is
> required.

You simply haven't really read anyone else's posts to understand what they
are stating.

[Alan Baker]

In article >,
Jim Logajan > wrote:

> Alan Baker > wrote:
> > If there is no downwash, it will not fly. No.
>
> You are arguing a point not under contention (at least with respect to
> heavier-than-air aircraft.)
>
> > See everyone: this is why understanding of the actual facts is
> > required.
>
> You simply haven't really read anyone else's posts to understand what they
> are stating.

The previous poster just said:

"Let's talk about helicopters. We can replace that rotor with a squirrel
cage fan. Air is drawn down into the fan as before, and most of the
pressure differential is due to lowering pressure above the fan. As
before... except that now the air is exhausted out the periphery of the
centrifugal-flow squirrel cage fan, not down as it was with the old
axial-flow rotor. Will it fly? Where's the downwash?"

She ("Beryl"?) is clearly implying that such an hypothetical craft could
remain airborne without downwash.

How else can it be read?

--
Alan Baker
Vancouver, British Columbia
<http://gallery.me.com/alangbaker/100008/DSCF0162/web.jpg>

[Beryl[_3_]]

Alan Baker wrote:
> In article >,
> Jim Logajan > wrote:
>
>> Alan Baker > wrote:
>>> If there is no downwash, it will not fly. No.
>> You are arguing a point not under contention (at least with respect to
>> heavier-than-air aircraft.)
>>
>>> See everyone: this is why understanding of the actual facts is
>>> required.

The ground isn't required. Air has inertia, and it's just as much a part
of the earth as dirt and rocks are. So why are you fixated on the
earth's solid surface? It compresses too, you know. You could argue that
the downforce travels through the whole planet and back into the
atmosphere in China.

>> You simply haven't really read anyone else's posts to understand what they
>> are stating.
>
> The previous poster just said:
>
> "Let's talk about helicopters. We can replace that rotor with a squirrel
> cage fan. Air is drawn down into the fan as before, and most of the
> pressure differential is due to lowering pressure above the fan. As
> before... except that now the air is exhausted out the periphery of the
> centrifugal-flow squirrel cage fan, not down as it was with the old
> axial-flow rotor. Will it fly? Where's the downwash?"
>
> She ("Beryl"?)

A mineral

> is clearly implying that such an hypothetical craft could remain airborne without downwash.

No, I only asked.

> How else can it be read?

Read it as a question.

[Alan Baker]

In article >,
Beryl > wrote:

> Alan Baker wrote:
> > In article >,
> > Jim Logajan > wrote:
> >
> >> Alan Baker > wrote:
> >>> If there is no downwash, it will not fly. No.
> >> You are arguing a point not under contention (at least with respect to
> >> heavier-than-air aircraft.)
> >>
> >>> See everyone: this is why understanding of the actual facts is
> >>> required.
>
> The ground isn't required. Air has inertia, and it's just as much a part
> of the earth as dirt and rocks are. So why are you fixated on the
> earth's solid surface? It compresses too, you know. You could argue that
> the downforce travels through the whole planet and back into the
> atmosphere in China.
>
> >> You simply haven't really read anyone else's posts to understand what they
> >> are stating.
> >
> > The previous poster just said:
> >
> > "Let's talk about helicopters. We can replace that rotor with a squirrel
> > cage fan. Air is drawn down into the fan as before, and most of the
> > pressure differential is due to lowering pressure above the fan. As
> > before... except that now the air is exhausted out the periphery of the
> > centrifugal-flow squirrel cage fan, not down as it was with the old
> > axial-flow rotor. Will it fly? Where's the downwash?"
> >
> > She ("Beryl"?)
>
> A mineral
>
> > is clearly implying that such an hypothetical craft could remain airborne
> > without downwash.
>
> No, I only asked.
>
> > How else can it be read?
>
> Read it as a question.

So what is your answer? Can the postulated craft fly if there is no
downdraft?

I'm betting you'll find a way to avoid answering...

--
Alan Baker
Vancouver, British Columbia
<http://gallery.me.com/alangbaker/100008/DSCF0162/web.jpg>

[Beryl[_3_]]

Alan Baker wrote:
> In article >,
> Beryl > wrote:
>
>> Alan Baker wrote:
>>> In article >,
>>> Jim Logajan > wrote:
>>>
>>>> Alan Baker > wrote:
>>>>> If there is no downwash, it will not fly. No.
>>>> You are arguing a point not under contention (at least with respect to
>>>> heavier-than-air aircraft.)
>>>>
>>>>> See everyone: this is why understanding of the actual facts is
>>>>> required.
>> The ground isn't required. Air has inertia, and it's just as much a part
>> of the earth as dirt and rocks are. So why are you fixated on the
>> earth's solid surface? It compresses too, you know. You could argue that
>> the downforce travels through the whole planet and back into the
>> atmosphere in China.
>>
>>>> You simply haven't really read anyone else's posts to understand what they
>>>> are stating.
>>> The previous poster just said:
>>>
>>> "Let's talk about helicopters. We can replace that rotor with a squirrel
>>> cage fan. Air is drawn down into the fan as before, and most of the
>>> pressure differential is due to lowering pressure above the fan. As
>>> before... except that now the air is exhausted out the periphery of the
>>> centrifugal-flow squirrel cage fan, not down as it was with the old
>>> axial-flow rotor. Will it fly? Where's the downwash?"
>>>
>>> She ("Beryl"?)
>> A mineral
>>
>>> is clearly implying that such an hypothetical craft could remain airborne
>>> without downwash.
>> No, I only asked.
>>
>>> How else can it be read?
>> Read it as a question.
>
> So what is your answer? Can the postulated craft fly if there is no
> downdraft?

The inflow strikes the underside of the conventional rotor disk, but
strikes the topside of the centrifugal fan disk. That's all!

> I'm betting you'll find a way to avoid answering...

I did.

So where are we? Your downward accelerated air might continue traveling
until it's stopped by the earth's surface, which is the only thing that
can stop it. But it isn't simply thrown down. Much of the finite energy
put into to the air is "wasted" in spinning it. Kinetic energy becomes heat.

[Alan Baker]

In article >,
Beryl > wrote:

> Alan Baker wrote:
> > In article >,
> > Beryl > wrote:
> >
> >> Alan Baker wrote:
> >>> In article >,
> >>> Jim Logajan > wrote:
> >>>
> >>>> Alan Baker > wrote:
> >>>>> If there is no downwash, it will not fly. No.
> >>>> You are arguing a point not under contention (at least with respect to
> >>>> heavier-than-air aircraft.)
> >>>>
> >>>>> See everyone: this is why understanding of the actual facts is
> >>>>> required.
> >> The ground isn't required. Air has inertia, and it's just as much a part
> >> of the earth as dirt and rocks are. So why are you fixated on the
> >> earth's solid surface? It compresses too, you know. You could argue that
> >> the downforce travels through the whole planet and back into the
> >> atmosphere in China.
> >>
> >>>> You simply haven't really read anyone else's posts to understand what
> >>>> they
> >>>> are stating.
> >>> The previous poster just said:
> >>>
> >>> "Let's talk about helicopters. We can replace that rotor with a squirrel
> >>> cage fan. Air is drawn down into the fan as before, and most of the
> >>> pressure differential is due to lowering pressure above the fan. As
> >>> before... except that now the air is exhausted out the periphery of the
> >>> centrifugal-flow squirrel cage fan, not down as it was with the old
> >>> axial-flow rotor. Will it fly? Where's the downwash?"
> >>>
> >>> She ("Beryl"?)
> >> A mineral
> >>
> >>> is clearly implying that such an hypothetical craft could remain airborne
> >>> without downwash.
> >> No, I only asked.
> >>
> >>> How else can it be read?
> >> Read it as a question.
> >
> > So what is your answer? Can the postulated craft fly if there is no
> > downdraft?
>
> The inflow strikes the underside of the conventional rotor disk, but
> strikes the topside of the centrifugal fan disk. That's all!
>
> > I'm betting you'll find a way to avoid answering...
>
> I did.
>

No surprise there.

> So where are we? Your downward accelerated air might continue traveling
> until it's stopped by the earth's surface, which is the only thing that
> can stop it. But it isn't simply thrown down. Much of the finite energy
> put into to the air is "wasted" in spinning it. Kinetic energy becomes heat.

And now you're just ducking.

--
Alan Baker
Vancouver, British Columbia
<http://gallery.me.com/alangbaker/100008/DSCF0162/web.jpg>

[Beryl[_3_]]

Alan Baker wrote:
> In article >,
> Beryl > wrote:
>
>> Alan Baker wrote:
>>> In article >,
>>> Beryl > wrote:
>>>
>>>> Alan Baker wrote:
>>>>> In article >,
>>>>> Jim Logajan > wrote:
>>>>>
>>>>>> Alan Baker > wrote:
>>>>>>> If there is no downwash, it will not fly. No.
>>>>>> You are arguing a point not under contention (at least with respect to
>>>>>> heavier-than-air aircraft.)
>>>>>>
>>>>>>> See everyone: this is why understanding of the actual facts is
>>>>>>> required.
>>>> The ground isn't required. Air has inertia, and it's just as much a part
>>>> of the earth as dirt and rocks are. So why are you fixated on the
>>>> earth's solid surface? It compresses too, you know. You could argue that
>>>> the downforce travels through the whole planet and back into the
>>>> atmosphere in China.
>>>>
>>>>>> You simply haven't really read anyone else's posts to understand what
>>>>>> they
>>>>>> are stating.
>>>>> The previous poster just said:
>>>>>
>>>>> "Let's talk about helicopters. We can replace that rotor with a squirrel
>>>>> cage fan. Air is drawn down into the fan as before, and most of the
>>>>> pressure differential is due to lowering pressure above the fan. As
>>>>> before... except that now the air is exhausted out the periphery of the
>>>>> centrifugal-flow squirrel cage fan, not down as it was with the old
>>>>> axial-flow rotor. Will it fly? Where's the downwash?"
>>>>>
>>>>> She ("Beryl"?)
>>>> A mineral
>>>>
>>>>> is clearly implying that such an hypothetical craft could remain airborne
>>>>> without downwash.
>>>> No, I only asked.
>>>>
>>>>> How else can it be read?
>>>> Read it as a question.
>>> So what is your answer? Can the postulated craft fly if there is no
>>> downdraft?
>> The inflow strikes the underside of the conventional rotor disk, but
>> strikes the topside of the centrifugal fan disk. That's all!
>>
>>> I'm betting you'll find a way to avoid answering...
>> I did.
>>
>
> No surprise there.
>
>> So where are we? Your downward accelerated air might continue traveling
>> until it's stopped by the earth's surface, which is the only thing that
>> can stop it. But it isn't simply thrown down. Much of the finite energy
>> put into to the air is "wasted" in spinning it. Kinetic energy becomes heat.
>
> And now you're just ducking.

Like you do, every time it's pointed out that when air is pushed down,
an equal volume of air must go UP? You then avoid saying "air flow" and
start grasping for other terms.

So how far down do you think air can flow before the ground is out of
reach? Forever?

[Alan Baker]

In article >,
Beryl > wrote:

> Alan Baker wrote:
> > In article >,
> > Beryl > wrote:
> >
> >> Alan Baker wrote:
> >>> In article >,
> >>> Beryl > wrote:
> >>>
> >>>> Alan Baker wrote:
> >>>>> In article >,
> >>>>> Jim Logajan > wrote:
> >>>>>
> >>>>>> Alan Baker > wrote:
> >>>>>>> If there is no downwash, it will not fly. No.
> >>>>>> You are arguing a point not under contention (at least with respect to
> >>>>>> heavier-than-air aircraft.)
> >>>>>>
> >>>>>>> See everyone: this is why understanding of the actual facts is
> >>>>>>> required.
> >>>> The ground isn't required. Air has inertia, and it's just as much a part
> >>>> of the earth as dirt and rocks are. So why are you fixated on the
> >>>> earth's solid surface? It compresses too, you know. You could argue that
> >>>> the downforce travels through the whole planet and back into the
> >>>> atmosphere in China.
> >>>>
> >>>>>> You simply haven't really read anyone else's posts to understand what
> >>>>>> they
> >>>>>> are stating.
> >>>>> The previous poster just said:
> >>>>>
> >>>>> "Let's talk about helicopters. We can replace that rotor with a
> >>>>> squirrel
> >>>>> cage fan. Air is drawn down into the fan as before, and most of the
> >>>>> pressure differential is due to lowering pressure above the fan. As
> >>>>> before... except that now the air is exhausted out the periphery of the
> >>>>> centrifugal-flow squirrel cage fan, not down as it was with the old
> >>>>> axial-flow rotor. Will it fly? Where's the downwash?"
> >>>>>
> >>>>> She ("Beryl"?)
> >>>> A mineral
> >>>>
> >>>>> is clearly implying that such an hypothetical craft could remain
> >>>>> airborne
> >>>>> without downwash.
> >>>> No, I only asked.
> >>>>
> >>>>> How else can it be read?
> >>>> Read it as a question.
> >>> So what is your answer? Can the postulated craft fly if there is no
> >>> downdraft?
> >> The inflow strikes the underside of the conventional rotor disk, but
> >> strikes the topside of the centrifugal fan disk. That's all!
> >>
> >>> I'm betting you'll find a way to avoid answering...
> >> I did.
> >>
> >
> > No surprise there.
> >
> >> So where are we? Your downward accelerated air might continue traveling
> >> until it's stopped by the earth's surface, which is the only thing that
> >> can stop it. But it isn't simply thrown down. Much of the finite energy
> >> put into to the air is "wasted" in spinning it. Kinetic energy becomes
> >> heat.
> >
> > And now you're just ducking.
>
> Like you do, every time it's pointed out that when air is pushed down,
> an equal volume of air must go UP? You then avoid saying "air flow" and
> start grasping for other terms.

Eventually it must go up. After it has transferred its momentum to the
earth.

I'm sorry, but that is the reality of the situation.

>
> So how far down do you think air can flow before the ground is out of
> reach? Forever?

Essentially, yes. The fact is that if the aircraft and the Earth are to
remain the same distance apart, the plane must "push" against the Earth
with a force equal to the force of gravity. The air is the medium by
which the aircraft can transmit that push.

And to explain to you why your hypothetical craft with the radial
exhaust of air from a centrifugal fan won't work. The air that enters
downward gets turned to go sideways. That 90 degree turn can only be
accomplished by the a push upward from the aircraft and thus the air
must push down on the system with an equal but opposite force.

--
Alan Baker
Vancouver, British Columbia
<http://gallery.me.com/alangbaker/100008/DSCF0162/web.jpg>

[Jim Logajan]

Alan Baker > wrote:
> Jim Logajan > wrote:
>> Because the airplane and the Earth have zero relative vertical
>> velocity during straight and level flight, conservation of momentum
>> requires the net vertical flow of air to also be zero.
>>
>> Therefore in subsonic flows where the fluid is assumed
>> incompressible, to the extent any fluid is moving downward,
>> conservation of mass requires an equal amount of mass must be moving
>> upward (the continuity requirement.)
>>
>> Hence airplanes must cause air to move in circles.
>
> Nope. Wrong.
>
> The aircraft is experience an force upward the entire time it is in
> flight. That force means there must be an equal force acting on the
> air, and since the air was not moving vertically (in our idealized
> case for this discussion) before the aircraft arrived, the force
> exerted on it must mean that it is moving downward afterward it has
> passed.

Nothing you wrote in your paragraph contradicts anything in my
paragraphs. So I'm at a loss therefore as to what specific statements you
claim are wrong. So how about I break it down into smaller claims and you
tell me which of these statements you agree with and which you disagree
with:

1) Conservation of momentum requires that at all times during flight that
net vertical momentum of the total system must be zero. Agree or
disagree?

2) We can treat air as incompressible, so conservation of mass means the
net vertical mass flow of the system during level flight must be zero.
Agree or disagree?

3) Therefore if, say, the downwash is 1 kg/s at any given instant due to
the wing, somewhere else in the fluid there must be an upwash at that
same instant of 1 kg/s. Agree or disagree?

4) Because upwash mass rate equals downwash mass rate, at some point the
downward flow reverses direction and becomes the upwash. Agree or
disagree?

>> Yes some deflection downward occurs. But I don't know that it could
>> be said to "diffuse" in any sense due to conservation of mass and
>> momentum requirements.
>
> As the air the plane has forced downward encounters more air, the
> momentum is diffused so that a greater and greater mass of air moves
> downward at smaller and smaller velocities (net)...
>
> ...until it encounters the ground.

Keep in mind that balloons need no downwash to stay aloft. Yet we know
from conservation laws that the *static* pressure on the surface of the
earth must be increase due to their presence. Nothing you've written
rules out the possibility that the *dynamic* pressure of the downwash
translates into a *static* pressure increase well before the downwash
reaches the surface of the earth. The physics of the situation do not
seem to rule out that a priori.

[Alan Baker]

In article >,
Jim Logajan > wrote:

> Alan Baker > wrote:
> > Jim Logajan > wrote:
> >> Because the airplane and the Earth have zero relative vertical
> >> velocity during straight and level flight, conservation of momentum
> >> requires the net vertical flow of air to also be zero.
> >>
> >> Therefore in subsonic flows where the fluid is assumed
> >> incompressible, to the extent any fluid is moving downward,
> >> conservation of mass requires an equal amount of mass must be moving
> >> upward (the continuity requirement.)
> >>
> >> Hence airplanes must cause air to move in circles.
> >
> > Nope. Wrong.
> >
> > The aircraft is experience an force upward the entire time it is in
> > flight. That force means there must be an equal force acting on the
> > air, and since the air was not moving vertically (in our idealized
> > case for this discussion) before the aircraft arrived, the force
> > exerted on it must mean that it is moving downward afterward it has
> > passed.
>
> Nothing you wrote in your paragraph contradicts anything in my
> paragraphs. So I'm at a loss therefore as to what specific statements you
> claim are wrong. So how about I break it down into smaller claims and you
> tell me which of these statements you agree with and which you disagree
> with:
>
> 1) Conservation of momentum requires that at all times during flight that
> net vertical momentum of the total system must be zero. Agree or
> disagree?
>
> 2) We can treat air as incompressible, so conservation of mass means the
> net vertical mass flow of the system during level flight must be zero.
> Agree or disagree?

Agree, but that system needs to include the Earth itself, doesn't it?

>
> 3) Therefore if, say, the downwash is 1 kg/s at any given instant due to
> the wing, somewhere else in the fluid there must be an upwash at that
> same instant of 1 kg/s. Agree or disagree?

Agree. At the surface of the Earth.
>
> 4) Because upwash mass rate equals downwash mass rate, at some point the
> downward flow reverses direction and becomes the upwash. Agree or
> disagree?

Agree. At the surface of the Earth.

>
> >> Yes some deflection downward occurs. But I don't know that it could
> >> be said to "diffuse" in any sense due to conservation of mass and
> >> momentum requirements.
> >
> > As the air the plane has forced downward encounters more air, the
> > momentum is diffused so that a greater and greater mass of air moves
> > downward at smaller and smaller velocities (net)...
> >
> > ...until it encounters the ground.
>
> Keep in mind that balloons need no downwash to stay aloft. Yet we know
> from conservation laws that the *static* pressure on the surface of the
> earth must be increase due to their presence. Nothing you've written
> rules out the possibility that the *dynamic* pressure of the downwash
> translates into a *static* pressure increase well before the downwash
> reaches the surface of the earth. The physics of the situation do not
> seem to rule out that a priori.

Conservation of momentum does.

--
Alan Baker
Vancouver, British Columbia
<http://gallery.me.com/alangbaker/100008/DSCF0162/web.jpg>

[Beryl[_3_]]

Alan Baker wrote:
> In article >,
> Beryl > wrote:
>
>> Alan Baker wrote:
>>> In article >,
>>> Beryl > wrote:
>>>
>>>> Alan Baker wrote:
>>>>> In article >,
>>>>> Beryl > wrote:
>>>>>
>>>>>> Alan Baker wrote:
>>>>>>> In article >,
>>>>>>> Jim Logajan > wrote:
>>>>>>>
>>>>>>>> Alan Baker > wrote:
>>>>>>>>> If there is no downwash, it will not fly. No.
>>>>>>>> You are arguing a point not under contention (at least with respect to
>>>>>>>> heavier-than-air aircraft.)
>>>>>>>>
>>>>>>>>> See everyone: this is why understanding of the actual facts is
>>>>>>>>> required.
>>>>>> The ground isn't required. Air has inertia, and it's just as much a part
>>>>>> of the earth as dirt and rocks are. So why are you fixated on the
>>>>>> earth's solid surface? It compresses too, you know. You could argue that
>>>>>> the downforce travels through the whole planet and back into the
>>>>>> atmosphere in China.
>>>>>>
>>>>>>>> You simply haven't really read anyone else's posts to understand what
>>>>>>>> they
>>>>>>>> are stating.
>>>>>>> The previous poster just said:
>>>>>>>
>>>>>>> "Let's talk about helicopters. We can replace that rotor with a
>>>>>>> squirrel
>>>>>>> cage fan. Air is drawn down into the fan as before, and most of the
>>>>>>> pressure differential is due to lowering pressure above the fan. As
>>>>>>> before... except that now the air is exhausted out the periphery of the
>>>>>>> centrifugal-flow squirrel cage fan, not down as it was with the old
>>>>>>> axial-flow rotor. Will it fly? Where's the downwash?"
>>>>>>>
>>>>>>> She ("Beryl"?)
>>>>>> A mineral
>>>>>>
>>>>>>> is clearly implying that such an hypothetical craft could remain
>>>>>>> airborne
>>>>>>> without downwash.
>>>>>> No, I only asked.
>>>>>>
>>>>>>> How else can it be read?
>>>>>> Read it as a question.
>>>>> So what is your answer? Can the postulated craft fly if there is no
>>>>> downdraft?
>>>> The inflow strikes the underside of the conventional rotor disk, but
>>>> strikes the topside of the centrifugal fan disk. That's all!
>>>>
>>>>> I'm betting you'll find a way to avoid answering...
>>>> I did.
>>>>
>>> No surprise there.
>>>
>>>> So where are we? Your downward accelerated air might continue traveling
>>>> until it's stopped by the earth's surface, which is the only thing that
>>>> can stop it. But it isn't simply thrown down. Much of the finite energy
>>>> put into to the air is "wasted" in spinning it. Kinetic energy becomes
>>>> heat.
>>> And now you're just ducking.
>> Like you do, every time it's pointed out that when air is pushed down,
>> an equal volume of air must go UP? You then avoid saying "air flow" and
>> start grasping for other terms.
>
> Eventually it must go up. After it has transferred its momentum to the
> earth.

You've seen pics of it curling right back up.
<http://www.efluids.com/efluids/gallery/gallery_pages/Morris_4.jsp>
It hasn't bounced off the ground.

> I'm sorry, but that is the reality of the situation.

Pressure waves can reach the ground, without the air in the column
descending to the ground.

>> So how far down do you think air can flow before the ground is out of
>> reach? Forever?
>
> Essentially, yes.

How? A wing doesn't keep pushing down on a parcel of air forever. It
gives that air a shove, then it moves on. That downward-shoved air
pushes the air below it out of the way, not just down, but sideways.
Then the sideways-moving air shoves its neighboring air out of the way,
not just sideways, but down and up. Add all the "downs" and subtract all
the "ups" until there's nothing left.

> The fact is that if the aircraft and the Earth are to remain the same distance apart, the plane must "push" against the Earth
> with a force equal to the force of gravity. The air is the medium by
> which the aircraft can transmit that push.

Right. And I can push against the hill across the road with my voice.
Not much, but enough to move the diaphragm in a microphone over there,
in a split second. The air expelled from lungs is never going to make it
across the road.

> And to explain to you why your hypothetical craft with the radial
> exhaust of air from a centrifugal fan won't work. The air that enters
> downward gets turned to go sideways. That 90 degree turn can only be
> accomplished by the a push upward from the aircraft and thus the air
> must push down on the system with an equal but opposite force.

But is that 90 degree turn *exactly* the same as a 180 degree turn that
directs incoming air back in the opposite direction? No, so I'll just
turn my squirrel cage upside down with 180 degree flow redirection, and
get lift with no net downwash.

[Alan Baker]

In article >,
Beryl > wrote:

> Alan Baker wrote:
> > In article >,
> > Beryl > wrote:
> >
> >> Alan Baker wrote:
> >>> In article >,
> >>> Beryl > wrote:
> >>>
> >>>> Alan Baker wrote:
> >>>>> In article >,
> >>>>> Beryl > wrote:
> >>>>>
> >>>>>> Alan Baker wrote:
> >>>>>>> In article >,
> >>>>>>> Jim Logajan > wrote:
> >>>>>>>
> >>>>>>>> Alan Baker > wrote:
> >>>>>>>>> If there is no downwash, it will not fly. No.
> >>>>>>>> You are arguing a point not under contention (at least with respect
> >>>>>>>> to
> >>>>>>>> heavier-than-air aircraft.)
> >>>>>>>>
> >>>>>>>>> See everyone: this is why understanding of the actual facts is
> >>>>>>>>> required.
> >>>>>> The ground isn't required. Air has inertia, and it's just as much a
> >>>>>> part
> >>>>>> of the earth as dirt and rocks are. So why are you fixated on the
> >>>>>> earth's solid surface? It compresses too, you know. You could argue
> >>>>>> that
> >>>>>> the downforce travels through the whole planet and back into the
> >>>>>> atmosphere in China.
> >>>>>>
> >>>>>>>> You simply haven't really read anyone else's posts to understand
> >>>>>>>> what
> >>>>>>>> they
> >>>>>>>> are stating.
> >>>>>>> The previous poster just said:
> >>>>>>>
> >>>>>>> "Let's talk about helicopters. We can replace that rotor with a
> >>>>>>> squirrel
> >>>>>>> cage fan. Air is drawn down into the fan as before, and most of the
> >>>>>>> pressure differential is due to lowering pressure above the fan. As
> >>>>>>> before... except that now the air is exhausted out the periphery of
> >>>>>>> the
> >>>>>>> centrifugal-flow squirrel cage fan, not down as it was with the old
> >>>>>>> axial-flow rotor. Will it fly? Where's the downwash?"
> >>>>>>>
> >>>>>>> She ("Beryl"?)
> >>>>>> A mineral
> >>>>>>
> >>>>>>> is clearly implying that such an hypothetical craft could remain
> >>>>>>> airborne
> >>>>>>> without downwash.
> >>>>>> No, I only asked.
> >>>>>>
> >>>>>>> How else can it be read?
> >>>>>> Read it as a question.
> >>>>> So what is your answer? Can the postulated craft fly if there is no
> >>>>> downdraft?
> >>>> The inflow strikes the underside of the conventional rotor disk, but
> >>>> strikes the topside of the centrifugal fan disk. That's all!
> >>>>
> >>>>> I'm betting you'll find a way to avoid answering...
> >>>> I did.
> >>>>
> >>> No surprise there.
> >>>
> >>>> So where are we? Your downward accelerated air might continue traveling
> >>>> until it's stopped by the earth's surface, which is the only thing that
> >>>> can stop it. But it isn't simply thrown down. Much of the finite energy
> >>>> put into to the air is "wasted" in spinning it. Kinetic energy becomes
> >>>> heat.
> >>> And now you're just ducking.
> >> Like you do, every time it's pointed out that when air is pushed down,
> >> an equal volume of air must go UP? You then avoid saying "air flow" and
> >> start grasping for other terms.
> >
> > Eventually it must go up. After it has transferred its momentum to the
> > earth.
>
> You've seen pics of it curling right back up.
> <http://www.efluids.com/efluids/gallery/gallery_pages/Morris_4.jsp>
> It hasn't bounced off the ground.

You've seen the edges curling back up. For anything with downward
momentum to start moving upward, something else has to start moving
downward.

Have you heard of "Conservation of Momentum"?

>
> > I'm sorry, but that is the reality of the situation.
>
> Pressure waves can reach the ground, without the air in the column
> descending to the ground.

I never said that the particular molecules that the aircraft touches are
the ones that have to reach the ground.

>
> >> So how far down do you think air can flow before the ground is out of
> >> reach? Forever?
> >
> > Essentially, yes.
>
> How? A wing doesn't keep pushing down on a parcel of air forever. It
> gives that air a shove, then it moves on. That downward-shoved air
> pushes the air below it out of the way, not just down, but sideways.
> Then the sideways-moving air shoves its neighboring air out of the way,
> not just sideways, but down and up. Add all the "downs" and subtract all
> the "ups" until there's nothing left.

Look up "Conservation of Momentum" and get back to me.

>
> > The fact is that if the aircraft and the Earth are to remain the same
> > distance apart, the plane must "push" against the Earth
> > with a force equal to the force of gravity. The air is the medium by
> > which the aircraft can transmit that push.
>
> Right. And I can push against the hill across the road with my voice.
> Not much, but enough to move the diaphragm in a microphone over there,
> in a split second. The air expelled from lungs is never going to make it
> across the road.

No, sorry. You don't push the hill with your voice. The pressure waves
contain both positive and negative phases.

>
> > And to explain to you why your hypothetical craft with the radial
> > exhaust of air from a centrifugal fan won't work. The air that enters
> > downward gets turned to go sideways. That 90 degree turn can only be
> > accomplished by the a push upward from the aircraft and thus the air
> > must push down on the system with an equal but opposite force.
>
> But is that 90 degree turn *exactly* the same as a 180 degree turn that
> directs incoming air back in the opposite direction? No, so I'll just
> turn my squirrel cage upside down with 180 degree flow redirection, and
> get lift with no net downwash.

No, you won't.

No downwash, no lift. No go learn something.

--
Alan Baker
Vancouver, British Columbia
<http://gallery.me.com/alangbaker/100008/DSCF0162/web.jpg>

[Beryl[_3_]]

Alan Baker wrote:
> In article >, Beryl
> > wrote:
...

>> You've seen pics of it curling right back up.
>> <http://www.efluids.com/efluids/gallery/gallery_pages/Morris_4.jsp>
>> It hasn't bounced off the ground.
>
> You've seen the edges curling back up.

That photo shows ALL of the flow curling back up. The bottom of the
vortex couldn't be any clearer, and there's nothing extending further
down underneath it.

>> Pressure waves can reach the ground, without the air in the column
>> descending to the ground.
>
> I never said that the particular molecules that the aircraft touches
> are the ones that have to reach the ground.

You said "The net flow is downward until it hits the ground and the
momentum is transfer to the earth."

The molecules that "reach" the ground are the ones that
were *already there* at ground level.

>>> The fact is that if the aircraft and the Earth are to remain the
>>> same distance apart, the plane must "push" against the Earth
>>> with a force equal to the force of gravity. The air is the medium
>>> by which the aircraft can transmit that push.
>>
>> Right. And I can push against the hill across the road with my
>> voice. Not much, but enough to move the diaphragm in a microphone
>> over there, in a split second. The air expelled from lungs is never
>> going to make it across the road.
>
> No, sorry. You don't push the hill with your voice.

Of course I do.

> The pressure waves contain both positive and negative phases.

So you think that a positive won't push because a negative will be
coming along shortly?

>>> And to explain to you why your hypothetical craft with the radial
>>> exhaust of air from a centrifugal fan won't work. The air that
>>> enters downward gets turned to go sideways. That 90 degree turn
>>> can only be accomplished by the a push upward from the aircraft
>>> and thus the air must push down on the system with an equal but
>>> opposite force.
>> But is that 90 degree turn *exactly* the same as a 180 degree turn
>> that directs incoming air back in the opposite direction? No, so
>> I'll just turn my squirrel cage upside down with 180 degree flow
>> redirection, and get lift with no net downwash.
>
> No, you won't.
>
> No downwash, no lift. No go learn something.

Let's learn here. From you. Is that 90 degree turn *exactly* the same as
a 180 degree turn that directs incoming air back in the opposite direction?

[Alan Baker]

In article >,
Beryl > wrote:

> Alan Baker wrote:
> > In article >, Beryl
> > > wrote:
> ...
>
> >> You've seen pics of it curling right back up.
> >> <http://www.efluids.com/efluids/gallery/gallery_pages/Morris_4.jsp>
> >> It hasn't bounced off the ground.
> >
> > You've seen the edges curling back up.
>
> That photo shows ALL of the flow curling back up. The bottom of the
> vortex couldn't be any clearer, and there's nothing extending further
> down underneath it.

Sorry, but you're wrong.

First of all, the downward motion of the vortex clearly carries right
out the bottom of the frame. Second, I've stated all along that as time
passes the momentum is diffused among more and more air.


>
> >> Pressure waves can reach the ground, without the air in the column
> >> descending to the ground.
> >
> > I never said that the particular molecules that the aircraft touches
> > are the ones that have to reach the ground.
>
> You said "The net flow is downward until it hits the ground and the
> momentum is transfer to the earth."

And it is: the *net* flow.

>
> The molecules that "reach" the ground are the ones that
> were *already there* at ground level.

I never implied that the same molecules are the ones that eventually
strike the ground.

>
> >>> The fact is that if the aircraft and the Earth are to remain the
> >>> same distance apart, the plane must "push" against the Earth
> >>> with a force equal to the force of gravity. The air is the medium
> >>> by which the aircraft can transmit that push.
> >>
> >> Right. And I can push against the hill across the road with my
> >> voice. Not much, but enough to move the diaphragm in a microphone
> >> over there, in a split second. The air expelled from lungs is never
> >> going to make it across the road.
> >
> > No, sorry. You don't push the hill with your voice.
>
> Of course I do.
>
> > The pressure waves contain both positive and negative phases.
>
> So you think that a positive won't push because a negative will be
> coming along shortly?

I think their will be no net push, yes.

See the difference: sound waves, no net flow: no net push.

>
> >>> And to explain to you why your hypothetical craft with the radial
> >>> exhaust of air from a centrifugal fan won't work. The air that
> >>> enters downward gets turned to go sideways. That 90 degree turn
> >>> can only be accomplished by the a push upward from the aircraft
> >>> and thus the air must push down on the system with an equal but
> >>> opposite force.
> >> But is that 90 degree turn *exactly* the same as a 180 degree turn
> >> that directs incoming air back in the opposite direction? No, so
> >> I'll just turn my squirrel cage upside down with 180 degree flow
> >> redirection, and get lift with no net downwash.
> >
> > No, you won't.
> >
> > No downwash, no lift. No go learn something.
>
> Let's learn here. From you. Is that 90 degree turn *exactly* the same as
> a 180 degree turn that directs incoming air back in the opposite direction?

Read this:

"To determine [the angle represented by a greek letter in the original
text], we observe that no downwash is generated when the wing generates
no lift."

<http://www.aoe.vt.edu/~cwoolsey/Courses/AOE3134/Supplemental/Aerodynamic
Properties.pdf>

Read it over and over again until you get it.

--
Alan Baker
Vancouver, British Columbia
<http://gallery.me.com/alangbaker/100008/DSCF0162/web.jpg>

[Beryl[_3_]]

Alan Baker wrote:
> In article >,
> Beryl > wrote:
>
>> Alan Baker wrote:
>>> In article >, Beryl
>>> > wrote:
>> ...
>>
>>>> You've seen pics of it curling right back up.
>>>> <http://www.efluids.com/efluids/gallery/gallery_pages/Morris_4.jsp>
>>>> It hasn't bounced off the ground.
>>> You've seen the edges curling back up.
>> That photo shows ALL of the flow curling back up. The bottom of the
>> vortex couldn't be any clearer, and there's nothing extending further
>> down underneath it.
>
> Sorry, but you're wrong.
>
> First of all, the downward motion of the vortex clearly carries right
> out the bottom of the frame.

Are you impaired? The airplane is approaching the camera. The camera is
looking up at the airplane. The bottom of the frame contains the distant
background. Objects farther than the airplane appear lower in the frame.
If the camera was above the approaching airplane and looking down at
it, distant objects would appear higher in the frame than the airplane.

> Second, I've stated all along that as time passes the momentum is diffused among more and more air.

Yes, you don't explain much, but you do stick to whatever you've said.

>>>> Pressure waves can reach the ground, without the air in the column
>>>> descending to the ground.
>>> I never said that the particular molecules that the aircraft touches
>>> are the ones that have to reach the ground.
>> You said "The net flow is downward until it hits the ground and the
>> momentum is transfer to the earth."
>
> And it is: the *net* flow.

The "net" flow is circulating air. Circulation circulates. It doesn't go
somewhere and stay there. The "net" displacement is zero.

>> The molecules that "reach" the ground are the ones that
>> were *already there* at ground level.
>
> I never implied that the same molecules are the ones that eventually
> strike the ground.

So then, the net flow stops when "it" hits the ground.
"It" isn't the molecules that the wing touches.
Would "it" be the molecules at the bottom of the air column? (they're
already on the ground)
Identify "it" and maybe we'll know when the flow stops.

>>>>> The fact is that if the aircraft and the Earth are to remain the
>>>>> same distance apart, the plane must "push" against the Earth
>>>>> with a force equal to the force of gravity. The air is the medium
>>>>> by which the aircraft can transmit that push.
>>>> Right. And I can push against the hill across the road with my
>>>> voice. Not much, but enough to move the diaphragm in a microphone
>>>> over there, in a split second. The air expelled from lungs is never
>>>> going to make it across the road.
>>> No, sorry. You don't push the hill with your voice.
>> Of course I do.
>>
>>> The pressure waves contain both positive and negative phases.
>> So you think that a positive won't push because a negative will be
>> coming along shortly?
>
> I think their will be no net push, yes.

There will be two pushes. There will be no net displacement.

> See the difference: sound waves, no net flow: no net push.

"No net push" doesn't make much sense here. There are opposing pushes,
but at _different_ times. That's the difference. By your reasoning,
microphones wouldn't work because the diaphragms inside won't move.

>>>>> And to explain to you why your hypothetical craft with the radial
>>>>> exhaust of air from a centrifugal fan won't work. The air that
>>>>> enters downward gets turned to go sideways. That 90 degree turn
>>>>> can only be accomplished by the a push upward from the aircraft
>>>>> and thus the air must push down on the system with an equal but
>>>>> opposite force.
>>>> But is that 90 degree turn *exactly* the same as a 180 degree turn
>>>> that directs incoming air back in the opposite direction? No, so
>>>> I'll just turn my squirrel cage upside down with 180 degree flow
>>>> redirection, and get lift with no net downwash.
>>> No, you won't.
>>>
>>> No downwash, no lift. No go learn something.
>> Let's learn here. From you. Is that 90 degree turn *exactly* the same as
>> a 180 degree turn that directs incoming air back in the opposite direction?
>
> Read this:
>
> "To determine [the angle represented by a greek letter in the original
> text], we observe that no downwash is generated when the wing generates
> no lift."

I'm not disagreeing with that. I'll rephrase it, and say no circulation
is generated. It is not even relevant.

> <http://www.aoe.vt.edu/~cwoolsey/Courses/AOE3134/Supplemental/Aerodynamic
> Properties.pdf>
>
> Read it over and over again until you get it.

Get what? It's about wings and geometry. Find something about air moving
through air.

[Alan Baker]

In article >,
Beryl > wrote:

> Alan Baker wrote:
> > In article >,
> > Beryl > wrote:
> >
> >> Alan Baker wrote:
> >>> In article >, Beryl
> >>> > wrote:
> >> ...
> >>
> >>>> You've seen pics of it curling right back up.
> >>>> <http://www.efluids.com/efluids/gallery/gallery_pages/Morris_4.jsp>
> >>>> It hasn't bounced off the ground.
> >>> You've seen the edges curling back up.
> >> That photo shows ALL of the flow curling back up. The bottom of the
> >> vortex couldn't be any clearer, and there's nothing extending further
> >> down underneath it.
> >
> > Sorry, but you're wrong.
> >
> > First of all, the downward motion of the vortex clearly carries right
> > out the bottom of the frame.
>
> Are you impaired? The airplane is approaching the camera. The camera is
> looking up at the airplane. The bottom of the frame contains the distant
> background. Objects farther than the airplane appear lower in the frame.
> If the camera was above the approaching airplane and looking down at
> it, distant objects would appear higher in the frame than the airplane.

None of which refutes what I said.

>
> > Second, I've stated all along that as time passes the momentum is diffused
> > among more and more air.
>
> Yes, you don't explain much, but you do stick to whatever you've said.

Because it's the truth.

Look up "conservation of momentum".

>
> >>>> Pressure waves can reach the ground, without the air in the column
> >>>> descending to the ground.
> >>> I never said that the particular molecules that the aircraft touches
> >>> are the ones that have to reach the ground.
> >> You said "The net flow is downward until it hits the ground and the
> >> momentum is transfer to the earth."
> >
> > And it is: the *net* flow.
>
> The "net" flow is circulating air. Circulation circulates. It doesn't go
> somewhere and stay there. The "net" displacement is zero.

No. If there were no net displacement, there would be no net change in
momentum. No net change in momentum means no force down on the air by
the aircraft. No force down on the air means no force up on the aircraft.

>
> >> The molecules that "reach" the ground are the ones that
> >> were *already there* at ground level.
> >
> > I never implied that the same molecules are the ones that eventually
> > strike the ground.
>
> So then, the net flow stops when "it" hits the ground.
> "It" isn't the molecules that the wing touches.

Correct.

> Would "it" be the molecules at the bottom of the air column? (they're
> already on the ground)
> Identify "it" and maybe we'll know when the flow stops.

The movement of air downward is "it".

>
> >>>>> The fact is that if the aircraft and the Earth are to remain the
> >>>>> same distance apart, the plane must "push" against the Earth
> >>>>> with a force equal to the force of gravity. The air is the medium
> >>>>> by which the aircraft can transmit that push.
> >>>> Right. And I can push against the hill across the road with my
> >>>> voice. Not much, but enough to move the diaphragm in a microphone
> >>>> over there, in a split second. The air expelled from lungs is never
> >>>> going to make it across the road.
> >>> No, sorry. You don't push the hill with your voice.
> >> Of course I do.
> >>
> >>> The pressure waves contain both positive and negative phases.
> >> So you think that a positive won't push because a negative will be
> >> coming along shortly?
> >
> > I think their will be no net push, yes.
>
> There will be two pushes. There will be no net displacement.
>
> > See the difference: sound waves, no net flow: no net push.
>
> "No net push" doesn't make much sense here. There are opposing pushes,
> but at _different_ times. That's the difference. By your reasoning,
> microphones wouldn't work because the diaphragms inside won't move.
>
> >>>>> And to explain to you why your hypothetical craft with the radial
> >>>>> exhaust of air from a centrifugal fan won't work. The air that
> >>>>> enters downward gets turned to go sideways. That 90 degree turn
> >>>>> can only be accomplished by the a push upward from the aircraft
> >>>>> and thus the air must push down on the system with an equal but
> >>>>> opposite force.
> >>>> But is that 90 degree turn *exactly* the same as a 180 degree turn
> >>>> that directs incoming air back in the opposite direction? No, so
> >>>> I'll just turn my squirrel cage upside down with 180 degree flow
> >>>> redirection, and get lift with no net downwash.
> >>> No, you won't.
> >>>
> >>> No downwash, no lift. No go learn something.
> >> Let's learn here. From you. Is that 90 degree turn *exactly* the same as
> >> a 180 degree turn that directs incoming air back in the opposite
> >> direction?
> >
> > Read this:
> >
> > "To determine [the angle represented by a greek letter in the original
> > text], we observe that no downwash is generated when the wing generates
> > no lift."
>
> I'm not disagreeing with that. I'll rephrase it, and say no circulation
> is generated. It is not even relevant.
>
> > <http://www.aoe.vt.edu/~cwoolsey/Courses/AOE3134/Supplemental/Aerodynamic
> > Properties.pdf>
> >
> > Read it over and over again until you get it.
>
> Get what? It's about wings and geometry. Find something about air moving
> through air.

"To determine [the angle represented by a greek letter in the original
text], we observe that no downwash is generated when the wing generates
no lift." isn't about air moving?

--
Alan Baker
Vancouver, British Columbia
<http://gallery.me.com/alangbaker/100008/DSCF0162/web.jpg>

[Alan Baker]

In article >,
Beryl > wrote:

<snip>

> >>> No downwash, no lift. No go learn something.
> >> Let's learn here. From you. Is that 90 degree turn *exactly* the same as
> >> a 180 degree turn that directs incoming air back in the opposite
> >> direction?
> >
> > Read this:
> >
> > "To determine [the angle represented by a greek letter in the original
> > text], we observe that no downwash is generated when the wing generates
> > no lift."
>
> I'm not disagreeing with that. I'll rephrase it, and say no circulation
> is generated. It is not even relevant.
>
> > <http://www.aoe.vt.edu/~cwoolsey/Courses/AOE3134/Supplemental/Aerodynamic
> > Properties.pdf>
> >
> > Read it over and over again until you get it.
>
> Get what? It's about wings and geometry. Find something about air moving
> through air.

<http://www.onemetre.net/Design/Downwash/Downwash.htm>

"The theory of downwash starts by noting that you only get downwash when
you have lift.* No lift, no downwash."

<http://amasci.com/wing/airfoil.html>

' The "Newton" explanation is wrong because downwash occurs BEHIND the
wing, where it can have no effects? Downwash can't generate a lifting
force? INCORRECT.

Wrong, and silly as well! The above statement caught fire on the
sci.physics newsgroup. Think for a moment: the exhaust from a rocket
or a jet engine occurs BEHIND the engine. Does this mean that
action/reaction does not apply to jets and rockets? Of course not.
It's true that the exhaust stream doesn't directly push on the inner
surface of a rocket engine. The lifting force in rockets is caused
by acceleration of mass, and within the exhaust plume the mass
is no longer accelerating. In rocket engines, the lifting force
appears in the same place that the exhaust is given high velocity:
where gases interact inside the engine.

And with aircraft, the lifting force appears in the same place that
the exhaust (the downwash) is given high downwards velocity. If a
wing encounters some unmoving air, and the wing then throws the air
downwards, the velocity of the air has been changed, and the wing
will experience an upwards reaction force. At the same time, a
downwash- flow is created. To calculate the lifting force of a
rocket engine, we can look exclusively at the exhaust velocity and
mass, but this doesn't mean that the rocket exhaust creates lift.
It just means that the rocket exhaust is directly proportional to
lift (since the exhaust velocity and the lifting force have a
common origin.) The same is true with airplane wings and downwash.
To have lift at high altitudes, we MUST have downwash, and if we
double the downwash, we double the lifting force. But downwash
doesn't cause lift, instead the wing's interaction with the air
both creates a lifting force and gives the air a downwards velocity
(by F=MA, don't you know!)'

--
Alan Baker
Vancouver, British Columbia
<http://gallery.me.com/alangbaker/100008/DSCF0162/web.jpg>

[Brian Whatcott]

Alan Baker wrote:

>>>> Pressure waves can reach the ground, without the air in the column
>>>> descending to the ground.
>>> I never said that the particular molecules that the aircraft touches
>>> are the ones that have to reach the ground.
>> You said "The net flow is downward until it hits the ground and the
>> momentum is transfer to the earth."
>
> And it is: the *net* flow.
>
>> The molecules that "reach" the ground are the ones that
>> were *already there* at ground level.

Hmmmm...It's not too out of line to think of air particles
at ambient temps as moving at the speed of sound.
Its those air "molecules" that carry sound waves longitudinally.
Air particles don't stay anywhere, in a manner of speaking...

Brian W

[Alan Baker]

In article >,
brian whatcott > wrote:

> Alan Baker wrote:
>
> >>>> Pressure waves can reach the ground, without the air in the column
> >>>> descending to the ground.
> >>> I never said that the particular molecules that the aircraft touches
> >>> are the ones that have to reach the ground.
> >> You said "The net flow is downward until it hits the ground and the
> >> momentum is transfer to the earth."
> >
> > And it is: the *net* flow.
> >
> >> The molecules that "reach" the ground are the ones that
> >> were *already there* at ground level.
>
> Hmmmm...It's not too out of line to think of air particles
> at ambient temps as moving at the speed of sound.

Actually, they move at considerably faster than the speed of sound...

> Its those air "molecules" that carry sound waves longitudinally.
> Air particles don't stay anywhere, in a manner of speaking...

--
Alan Baker
Vancouver, British Columbia
<http://gallery.me.com/alangbaker/100008/DSCF0162/web.jpg>

[Jim Logajan]

Alan Baker > wrote:
> Jim Logajan > wrote:
>> 3) Therefore if, say, the downwash is 1 kg/s at any given instant due
>> to the wing, somewhere else in the fluid there must be an upwash at
>> that same instant of 1 kg/s. Agree or disagree?
>
> Agree. At the surface of the Earth.

The qualifier indicates to me that you don't agree with the statement as
written.

Unfortunately, I consider conservation of mass at all points in time in an
incompressible fluid an essential element to understanding the behavior of
downwash. If you don't, then I think any further debate between us is
ended.

(Just FYI, imagine a ~957 kg (Fg ~= 9379 N) helicopter dropped from a
balloon from 3,000 m altitude (rho ~= 0.83 kg/m^3) and it's engine
immediately started. After a small drop it levels out and maintains a
downwash of air moving through its 6 m diameter disk (A ~= 28 m^2) at, say,
20 m/s. (So m_dot ~= 469 kg/s and hence Fe = Fg.)

It would take ~150 s for that downwash to reach the ground if it maintained
that speed. In the mean time, once the helicopter stopped descending,
conservation of mass in an incompressible fluid seems to require an equal
volume of air to have an upward vector of 20 m/s. So the surface of earth
appears to be irrelevant for over two minutes.)

[Beryl[_3_]]

Alan Baker wrote:
...
>>> First of all, the downward motion of the vortex clearly carries right
>>> out the bottom of the frame.
>> Are you impaired? The airplane is approaching the camera. The camera is
>> looking up at the airplane. The bottom of the frame contains the distant
>> background. Objects farther than the airplane appear lower in the frame.
>> If the camera was above the approaching airplane and looking down at
>> it, distant objects would appear higher in the frame than the airplane.
>
> None of which refutes what I said.

Oh, it was simply interesting to you that the vortex goes off into the
distance, right out the bottom of the picture.

[Alan Baker]

In article >,
Jim Logajan > wrote:

> Alan Baker > wrote:
> > Jim Logajan > wrote:
> >> 3) Therefore if, say, the downwash is 1 kg/s at any given instant due
> >> to the wing, somewhere else in the fluid there must be an upwash at
> >> that same instant of 1 kg/s. Agree or disagree?
> >
> > Agree. At the surface of the Earth.
>
> The qualifier indicates to me that you don't agree with the statement as
> written.

You're right. I shouldn't have stated it that way.

>
> Unfortunately, I consider conservation of mass at all points in time in an
> incompressible fluid an essential element to understanding the behavior of
> downwash. If you don't, then I think any further debate between us is
> ended.

Look if you think that conservation of *mass* plays any role in this,
you're missing out from the start. It's conservation of *momentum*
that's in play here.

The aircraft has a force exerted on it equal to its weight. That means
that the aircraft must be exerting a force on the air in the opposite
direction.

That means that there is a constant change of momentum being done on the
air by the aircraft. That means air *must* be moving down (net) after
the aircraft has passed.

>
> (Just FYI, imagine a ~957 kg (Fg ~= 9379 N) helicopter dropped from a
> balloon from 3,000 m altitude (rho ~= 0.83 kg/m^3) and it's engine
> immediately started. After a small drop it levels out and maintains a
> downwash of air moving through its 6 m diameter disk (A ~= 28 m^2) at, say,
> 20 m/s. (So m_dot ~= 469 kg/s and hence Fe = Fg.)
>
> It would take ~150 s for that downwash to reach the ground if it maintained
> that speed. In the mean time, once the helicopter stopped descending,
> conservation of mass in an incompressible fluid seems to require an equal
> volume of air to have an upward vector of 20 m/s. So the surface of earth
> appears to be irrelevant for over two minutes.)

Nope.

The conservation of momentum says that there cannot be an equal amount
of air moving upward at an equal speed.

--
Alan Baker
Vancouver, British Columbia
<http://gallery.me.com/alangbaker/100008/DSCF0162/web.jpg>

[Alan Baker]

In article >,
Beryl > wrote:

> Alan Baker wrote:
> ...
> >>> First of all, the downward motion of the vortex clearly carries right
> >>> out the bottom of the frame.
> >> Are you impaired? The airplane is approaching the camera. The camera is
> >> looking up at the airplane. The bottom of the frame contains the distant
> >> background. Objects farther than the airplane appear lower in the frame.
> >> If the camera was above the approaching airplane and looking down at
> >> it, distant objects would appear higher in the frame than the airplane.
> >
> > None of which refutes what I said.
>
> Oh, it was simply interesting to you that the vortex goes off into the
> distance, right out the bottom of the picture.

No. That shows that the air continues to move downward far below the
small portion of the vortex which is moving up.

The net movement of the air after the plane's passing must be downward,
because the plane is exerting a force on the air.

Force is a change of momentum with respect to time.

--
Alan Baker
Vancouver, British Columbia
<http://gallery.me.com/alangbaker/100008/DSCF0162/web.jpg>

[Jim Logajan]

Alan Baker > wrote:
> Look if you think that conservation of *mass* plays any role in this,
> you're missing out from the start. It's conservation of *momentum*
> that's in play here.

It appears you have never studied fluid dynamics (maybe elementary fluid
statics?) and I doubt that you own any books on the subject.

> The aircraft has a force exerted on it equal to its weight. That means
> that the aircraft must be exerting a force on the air in the opposite
> direction.

In other news, 1 + 1 = 2.

> That means that there is a constant change of momentum being done on
> the air by the aircraft. That means air *must* be moving down (net)
> after the aircraft has passed.

You must have a devil of a time figuring out what keeps balloons afloat,
what with no handy downward moving air!

>> (Just FYI, imagine a ~957 kg (Fg ~= 9379 N) helicopter dropped from a
>> balloon from 3,000 m altitude (rho ~= 0.83 kg/m^3) and it's engine
>> immediately started. After a small drop it levels out and maintains a
>> downwash of air moving through its 6 m diameter disk (A ~= 28 m^2)
>> at, say, 20 m/s. (So m_dot ~= 469 kg/s and hence Fe = Fg.)
>>
>> It would take ~150 s for that downwash to reach the ground if it
>> maintained that speed. In the mean time, once the helicopter stopped
>> descending, conservation of mass in an incompressible fluid seems to
>> require an equal volume of air to have an upward vector of 20 m/s. So
>> the surface of earth appears to be irrelevant for over two minutes.)
>
> Nope.

Dang - I try to use real numbers to establish a baseline example, and you
manage to use a single word to demolish my attempts! Really helpful
mathematical counter-example you produced - not.

> The conservation of momentum says that there cannot be an equal amount
> of air moving upward at an equal speed.

I don't know what your problem is - maybe you are thinking this is a
rocket problem where no external fluids are involved and you can't get
your mind around the fact that THIS ISN'T A BLOODY ROCKET PROBLEM.
Whatever the case, you seem to be fixated on applying one conservation
law to one element in the entire system to the exclusion of everything
else.

Best of luck to you.

[cavelamb[_2_]]

Jim Logajan wrote:
> Alan Baker > wrote:
>> Look if you think that conservation of *mass* plays any role in this,
>> you're missing out from the start. It's conservation of *momentum*
>> that's in play here.
>
> It appears you have never studied fluid dynamics (maybe elementary fluid
> statics?) and I doubt that you own any books on the subject.
>
>> The aircraft has a force exerted on it equal to its weight. That means
>> that the aircraft must be exerting a force on the air in the opposite
>> direction.
>
> In other news, 1 + 1 = 2.
>
>> That means that there is a constant change of momentum being done on
>> the air by the aircraft. That means air *must* be moving down (net)
>> after the aircraft has passed.
>
> You must have a devil of a time figuring out what keeps balloons afloat,
> what with no handy downward moving air!
>
>>> (Just FYI, imagine a ~957 kg (Fg ~= 9379 N) helicopter dropped from a
>>> balloon from 3,000 m altitude (rho ~= 0.83 kg/m^3) and it's engine
>>> immediately started. After a small drop it levels out and maintains a
>>> downwash of air moving through its 6 m diameter disk (A ~= 28 m^2)
>>> at, say, 20 m/s. (So m_dot ~= 469 kg/s and hence Fe = Fg.)
>>>
>>> It would take ~150 s for that downwash to reach the ground if it
>>> maintained that speed. In the mean time, once the helicopter stopped
>>> descending, conservation of mass in an incompressible fluid seems to
>>> require an equal volume of air to have an upward vector of 20 m/s. So
>>> the surface of earth appears to be irrelevant for over two minutes.)
>> Nope.
>
> Dang - I try to use real numbers to establish a baseline example, and you
> manage to use a single word to demolish my attempts! Really helpful
> mathematical counter-example you produced - not.
>
>> The conservation of momentum says that there cannot be an equal amount
>> of air moving upward at an equal speed.
>
> I don't know what your problem is - maybe you are thinking this is a
> rocket problem where no external fluids are involved and you can't get
> your mind around the fact that THIS ISN'T A BLOODY ROCKET PROBLEM.
> Whatever the case, you seem to be fixated on applying one conservation
> law to one element in the entire system to the exclusion of everything
> else.
>
> Best of luck to you.



Two dimensional Newtonian thinking in a three dimensional non-Newtonian world.

[Alan Baker]

In article >,
Jim Logajan > wrote:

> Alan Baker > wrote:
> > Look if you think that conservation of *mass* plays any role in this,
> > you're missing out from the start. It's conservation of *momentum*
> > that's in play here.
>
> It appears you have never studied fluid dynamics (maybe elementary fluid
> statics?) and I doubt that you own any books on the subject.

Sorry, lad, but conservation of mass is a principle that comes up mostly
in *chemistry*.

>
> > The aircraft has a force exerted on it equal to its weight. That means
> > that the aircraft must be exerting a force on the air in the opposite
> > direction.
>
> In other news, 1 + 1 = 2.

What a pity then that you don't understand it.

>
> > That means that there is a constant change of momentum being done on
> > the air by the aircraft. That means air *must* be moving down (net)
> > after the aircraft has passed.
>
> You must have a devil of a time figuring out what keeps balloons afloat,
> what with no handy downward moving air!

I have no trouble figuring that out at all. A gas of a different density
within the balloon causes the net upward force on the balloon exerted by
the air outside the balloon to be greater than the net downward force on
it.

>
> >> (Just FYI, imagine a ~957 kg (Fg ~= 9379 N) helicopter dropped from a
> >> balloon from 3,000 m altitude (rho ~= 0.83 kg/m^3) and it's engine
> >> immediately started. After a small drop it levels out and maintains a
> >> downwash of air moving through its 6 m diameter disk (A ~= 28 m^2)
> >> at, say, 20 m/s. (So m_dot ~= 469 kg/s and hence Fe = Fg.)
> >>
> >> It would take ~150 s for that downwash to reach the ground if it
> >> maintained that speed. In the mean time, once the helicopter stopped
> >> descending, conservation of mass in an incompressible fluid seems to
> >> require an equal volume of air to have an upward vector of 20 m/s. So
> >> the surface of earth appears to be irrelevant for over two minutes.)
> >
> > Nope.
>
> Dang - I try to use real numbers to establish a baseline example, and you
> manage to use a single word to demolish my attempts! Really helpful
> mathematical counter-example you produced - not.

No math is necessary for this. Look up "qualitative analysis".



>
> > The conservation of momentum says that there cannot be an equal amount
> > of air moving upward at an equal speed.
>
> I don't know what your problem is - maybe you are thinking this is a
> rocket problem where no external fluids are involved and you can't get
> your mind around the fact that THIS ISN'T A BLOODY ROCKET PROBLEM.
> Whatever the case, you seem to be fixated on applying one conservation
> law to one element in the entire system to the exclusion of everything
> else.

The law I'm focussed on is the one that counts. It doesn't matter
whether the fluid is expelled from inside or whether it's an external
fluid diverted down by the surfaces of the craft.

In order for there to be a continuous force W equaling the weight of the
craft acting on it, the craft must exert a force -W on the fluid. That
-W means that there is a downward change of momentum in the fluid. Since
the fluid is no accelerated indefinitely, there must be a continuous
flow (mass per unit time M/t) of the fluid accelerated to a velocity V
where the equation looks like:

-W = M/t * V

The velocity of the fluid will be:

V = -W/(M/t)

That is inescapable. If the craft weighs 9800N (newtons), and it moves
100kg of air every second, then the air must be moving downward (net,
now!) at 98 m/s.

I'm sorry if you don't get this, but it is very simple and absolutely
irrefutable.

--
Alan Baker
Vancouver, British Columbia
<http://gallery.me.com/alangbaker/100008/DSCF0162/web.jpg>

[Alan Baker]

In article >,
cavelamb > wrote:

> Jim Logajan wrote:
> > Alan Baker > wrote:
> >> Look if you think that conservation of *mass* plays any role in this,
> >> you're missing out from the start. It's conservation of *momentum*
> >> that's in play here.
> >
> > It appears you have never studied fluid dynamics (maybe elementary fluid
> > statics?) and I doubt that you own any books on the subject.
> >
> >> The aircraft has a force exerted on it equal to its weight. That means
> >> that the aircraft must be exerting a force on the air in the opposite
> >> direction.
> >
> > In other news, 1 + 1 = 2.
> >
> >> That means that there is a constant change of momentum being done on
> >> the air by the aircraft. That means air *must* be moving down (net)
> >> after the aircraft has passed.
> >
> > You must have a devil of a time figuring out what keeps balloons afloat,
> > what with no handy downward moving air!
> >
> >>> (Just FYI, imagine a ~957 kg (Fg ~= 9379 N) helicopter dropped from a
> >>> balloon from 3,000 m altitude (rho ~= 0.83 kg/m^3) and it's engine
> >>> immediately started. After a small drop it levels out and maintains a
> >>> downwash of air moving through its 6 m diameter disk (A ~= 28 m^2)
> >>> at, say, 20 m/s. (So m_dot ~= 469 kg/s and hence Fe = Fg.)
> >>>
> >>> It would take ~150 s for that downwash to reach the ground if it
> >>> maintained that speed. In the mean time, once the helicopter stopped
> >>> descending, conservation of mass in an incompressible fluid seems to
> >>> require an equal volume of air to have an upward vector of 20 m/s. So
> >>> the surface of earth appears to be irrelevant for over two minutes.)
> >> Nope.
> >
> > Dang - I try to use real numbers to establish a baseline example, and you
> > manage to use a single word to demolish my attempts! Really helpful
> > mathematical counter-example you produced - not.
> >
> >> The conservation of momentum says that there cannot be an equal amount
> >> of air moving upward at an equal speed.
> >
> > I don't know what your problem is - maybe you are thinking this is a
> > rocket problem where no external fluids are involved and you can't get
> > your mind around the fact that THIS ISN'T A BLOODY ROCKET PROBLEM.
> > Whatever the case, you seem to be fixated on applying one conservation
> > law to one element in the entire system to the exclusion of everything
> > else.
> >
> > Best of luck to you.
>
>
>
> Two dimensional Newtonian thinking in a three dimensional non-Newtonian world.

LOL

Sorry, caveman....


But conservation of momentum works well enough at the speeds at which
aircraft operate.

And Newton's laws tell us all we need to know.

--
Alan Baker
Vancouver, British Columbia
<http://gallery.me.com/alangbaker/100008/DSCF0162/web.jpg>

[Beryl[_3_]]

Alan Baker wrote:
> In article >,
> Beryl > wrote:
>
>> Alan Baker wrote:
>> ...
>>>>> First of all, the downward motion of the vortex clearly carries right
>>>>> out the bottom of the frame.
>>>> Are you impaired? The airplane is approaching the camera. The camera is
>>>> looking up at the airplane. The bottom of the frame contains the distant
>>>> background. Objects farther than the airplane appear lower in the frame.
>>>> If the camera was above the approaching airplane and looking down at
>>>> it, distant objects would appear higher in the frame than the airplane.
>>> None of which refutes what I said.
>> Oh, it was simply interesting to you that the vortex goes off into the
>> distance, right out the bottom of the picture.
>
> No. That shows that the air continues to move downward far below the
> small portion of the vortex which is moving up.

No it doesn't. Perspective shows nothing. If the camera was above the
approaching airplane and looking down at it, the picture would show that
the air continues to move upward far above the small portion of the
vortex which is showing up.

[Beryl[_3_]]

Alan Baker wrote:

> It's true that the exhaust stream doesn't directly push on the inner
> surface of a rocket engine.

Yeah, I like that aerospike design, the inside-out nozzle thing.

> wing encounters some unmoving air, and the wing then throws the air
> downwards, the velocity of the air has been changed, and the wing
> will experience an upwards reaction force. At the same time, a
> downwash- flow is created.

The wing, remember, is moving forward. "Downwards" is one component of
circulation.

[Beryl[_3_]]

Alan Baker wrote:
> In article >,
> Jim Logajan > wrote:

>> You must have a devil of a time figuring out what keeps balloons afloat,
>> what with no handy downward moving air!
>
> I have no trouble figuring that out at all. A gas of a different density
> within the balloon causes the net upward force on the balloon exerted by
> the air outside the balloon to be greater than the net downward force on
> it.

Nope! The "gas of a different density" inside does not cause the
differential forces exerted by the air outside. Whether the balloon is
filled with phlogiston or concrete, the difference between upward and
downward forces exerted by the air outside depends on the height of the
balloon. That's what my goofy 10,000 foot thick wing was, that would
take off with no airspeed or power. A balloon.

[Alan Baker]

In article >,
Beryl > wrote:

> Alan Baker wrote:
> > In article >,
> > Beryl > wrote:
> >
> >> Alan Baker wrote:
> >> ...
> >>>>> First of all, the downward motion of the vortex clearly carries right
> >>>>> out the bottom of the frame.
> >>>> Are you impaired? The airplane is approaching the camera. The camera is
> >>>> looking up at the airplane. The bottom of the frame contains the distant
> >>>> background. Objects farther than the airplane appear lower in the frame.
> >>>> If the camera was above the approaching airplane and looking down at
> >>>> it, distant objects would appear higher in the frame than the airplane.
> >>> None of which refutes what I said.
> >> Oh, it was simply interesting to you that the vortex goes off into the
> >> distance, right out the bottom of the picture.
> >
> > No. That shows that the air continues to move downward far below the
> > small portion of the vortex which is moving up.
>
> No it doesn't. Perspective shows nothing. If the camera was above the
> approaching airplane and looking down at it, the picture would show that
> the air continues to move upward far above the small portion of the
> vortex which is showing up.

LOL

Perspective would show the same amount of movement at greater and
greater distances as less and less absolute distance on the picture.

But the downward flow goes right off the bottom of the page...

--
Alan Baker
Vancouver, British Columbia
<http://gallery.me.com/alangbaker/100008/DSCF0162/web.jpg>

[Alan Baker]

In article >,
Beryl > wrote:

> Alan Baker wrote:
>
> > It's true that the exhaust stream doesn't directly push on the inner
> > surface of a rocket engine.
>
> Yeah, I like that aerospike design, the inside-out nozzle thing.
>
> > wing encounters some unmoving air, and the wing then throws the air
> > downwards, the velocity of the air has been changed, and the wing
> > will experience an upwards reaction force. At the same time, a
> > downwash- flow is created.
>
> The wing, remember, is moving forward. "Downwards" is one component of
> circulation.

Those weren't my words.

Yes, but Newton's laws tell us that there is a net force down on the
air. No net force down on the air, no net force up on the plane.

Force is change of momentum with respect to time.

--
Alan Baker
Vancouver, British Columbia
<http://gallery.me.com/alangbaker/100008/DSCF0162/web.jpg>

[Alan Baker]

In article >,
Beryl > wrote:

> Alan Baker wrote:
> > In article >,
> > Jim Logajan > wrote:
>
> >> You must have a devil of a time figuring out what keeps balloons afloat,
> >> what with no handy downward moving air!
> >
> > I have no trouble figuring that out at all. A gas of a different density
> > within the balloon causes the net upward force on the balloon exerted by
> > the air outside the balloon to be greater than the net downward force on
> > it.
>
> Nope! The "gas of a different density" inside does not cause the
> differential forces exerted by the air outside. Whether the balloon is
> filled with phlogiston or concrete, the difference between upward and
> downward forces exerted by the air outside depends on the height of the
> balloon. That's what my goofy 10,000 foot thick wing was, that would
> take off with no airspeed or power. A balloon.

You're wrong.

The "net downward force" includes the force of gravity. Which is
lessened because a gas of lower density..

....I can't believe I have to explain things so basic.

--
Alan Baker
Vancouver, British Columbia
<http://gallery.me.com/alangbaker/100008/DSCF0162/web.jpg>

[Alan Baker]

In article >,
Alan Baker > wrote:

> In article >,
> Beryl > wrote:
>
> > Alan Baker wrote:
> >
> > > It's true that the exhaust stream doesn't directly push on the inner
> > > surface of a rocket engine.
> >
> > Yeah, I like that aerospike design, the inside-out nozzle thing.
> >
> > > wing encounters some unmoving air, and the wing then throws the air
> > > downwards, the velocity of the air has been changed, and the wing
> > > will experience an upwards reaction force. At the same time, a
> > > downwash- flow is created.
> >
> > The wing, remember, is moving forward. "Downwards" is one component of
> > circulation.
>
> Those weren't my words.
>
> Yes, but Newton's laws tell us that there is a net force down on the
> air. No net force down on the air, no net force up on the plane.
>
> Force is change of momentum with respect to time.

BTW, the man whom you are contradicting is Scott Eberhardt, Bachelors &
Masters Degrees in Aeronautics and Astronautics from MIT, Ph.D. in the
same field from Stanford, research scientist at the NASA Ames Research
Center, faculty of the University of Washington.

But... ...really...

<http://books.google.com/books?id=wmuPXQuZnGoC&pg=PT5&lpg=PT5&dq=Scott+Eb
erhardt+aeronautics+and+astronautics&source=bl&ots=skN-zbDvej&sig=msQ-_Im
p6t-P62ehNWIld7RRYWs&hl=en&ei=GgEeS4f4AYzStgPB5eiCCg&sa=X&oi=book_result&
ct=result&resnum=6&ved=0CBsQ6AEwBQ#v=onepage&q=downwash&f=false>

....what would *HE* know about it compared to you?

LOL

--
Alan Baker
Vancouver, British Columbia
<http://gallery.me.com/alangbaker/100008/DSCF0162/web.jpg>

[Beryl[_3_]]

Alan Baker wrote:
> In article >,
> Beryl > wrote:
>
>> Alan Baker wrote:
>>> In article >,
>>> Beryl > wrote:
>>>
>>>> Alan Baker wrote:
>>>> ...
>>>>>>> First of all, the downward motion of the vortex clearly carries right
>>>>>>> out the bottom of the frame.
>>>>>> Are you impaired? The airplane is approaching the camera. The camera is
>>>>>> looking up at the airplane. The bottom of the frame contains the distant
>>>>>> background. Objects farther than the airplane appear lower in the frame.
>>>>>> If the camera was above the approaching airplane and looking down at
>>>>>> it, distant objects would appear higher in the frame than the airplane.
>>>>> None of which refutes what I said.
>>>> Oh, it was simply interesting to you that the vortex goes off into the
>>>> distance, right out the bottom of the picture.
>>> No. That shows that the air continues to move downward far below the
>>> small portion of the vortex which is moving up.
>> No it doesn't. Perspective shows nothing. If the camera was above the
>> approaching airplane and looking down at it, the picture would show that
>> the air continues to move upward far above the small portion of the
>> vortex which is showing up.
>
> LOL
>
> Perspective would show the same amount of movement at greater and
> greater distances as less and less absolute distance on the picture.

You're talking about a vanishing point. Has nothing to do with this.

> But the downward flow goes right off the bottom of the page...

Because the viewer is looking up at it!

Look!!!
http://www.efluids.com/efluids/gallery/gallery_pages/cessnajet_1.htm
OMG the downward flow went up!!!

[Beryl[_3_]]

Alan Baker wrote:
> In article >,
> Beryl > wrote:
>
>> Alan Baker wrote:
>>
>>> It's true that the exhaust stream doesn't directly push on the inner
>>> surface of a rocket engine.
>> Yeah, I like that aerospike design, the inside-out nozzle thing.
>>
>>> wing encounters some unmoving air, and the wing then throws the air
>>> downwards, the velocity of the air has been changed, and the wing
>>> will experience an upwards reaction force. At the same time, a
>>> downwash- flow is created.
>> The wing, remember, is moving forward. "Downwards" is one component of
>> circulation.
>
> Those weren't my words.

What do you suppose happens to "downwash" when it goes up? Say, pulling
positive G force at the top of a loop? Now you lost the surface of the
earth, the only thing that, according to you, finally stops it.

[Alan Baker]

In article >,
Beryl > wrote:

> Alan Baker wrote:
> > In article >,
> > Beryl > wrote:
> >
> >> Alan Baker wrote:
> >>
> >>> It's true that the exhaust stream doesn't directly push on the inner
> >>> surface of a rocket engine.
> >> Yeah, I like that aerospike design, the inside-out nozzle thing.
> >>
> >>> wing encounters some unmoving air, and the wing then throws the air
> >>> downwards, the velocity of the air has been changed, and the wing
> >>> will experience an upwards reaction force. At the same time, a
> >>> downwash- flow is created.
> >> The wing, remember, is moving forward. "Downwards" is one component of
> >> circulation.
> >
> > Those weren't my words.
>
> What do you suppose happens to "downwash" when it goes up? Say, pulling
> positive G force at the top of a loop? Now you lost the surface of the
> earth, the only thing that, according to you, finally stops it.

The earth still stops it:

Gravity: perhaps you've heard of it?

--
Alan Baker
Vancouver, British Columbia
<http://gallery.me.com/alangbaker/100008/DSCF0162/web.jpg>

[Beryl[_3_]]

Alan Baker wrote:
> In article >,
> Beryl > wrote:
>
>> Alan Baker wrote:
>>> In article >,
>>> Jim Logajan > wrote:
>>>> You must have a devil of a time figuring out what keeps balloons afloat,
>>>> what with no handy downward moving air!
>>> I have no trouble figuring that out at all. A gas of a different density
>>> within the balloon causes the net upward force on the balloon exerted by
>>> the air outside the balloon to be greater than the net downward force on
>>> it.
>> Nope! The "gas of a different density" inside does not cause the
>> differential forces exerted by the air outside. Whether the balloon is
>> filled with phlogiston or concrete, the difference between upward and
>> downward forces exerted by the air outside depends on the height of the
>> balloon. That's what my goofy 10,000 foot thick wing was, that would
>> take off with no airspeed or power. A balloon.
>
> You're wrong.
>
> The "net downward force" includes the force of gravity. Which is
> lessened because a gas of lower density..
>
> ...I can't believe I have to explain things so basic.

I know, but you have to. Your first attempt didn't appear to include
unsaid gravity. Gas that you described as "within the balloon" is now
treated as "part of" the balloon.

[Alan Baker]

In article >,
Beryl > wrote:

> Alan Baker wrote:
> > In article >,
> > Beryl > wrote:
> >
> >> Alan Baker wrote:
> >>> In article >,
> >>> Jim Logajan > wrote:
> >>>> You must have a devil of a time figuring out what keeps balloons afloat,
> >>>> what with no handy downward moving air!
> >>> I have no trouble figuring that out at all. A gas of a different density
> >>> within the balloon causes the net upward force on the balloon exerted by
> >>> the air outside the balloon to be greater than the net downward force on
> >>> it.
> >> Nope! The "gas of a different density" inside does not cause the
> >> differential forces exerted by the air outside. Whether the balloon is
> >> filled with phlogiston or concrete, the difference between upward and
> >> downward forces exerted by the air outside depends on the height of the
> >> balloon. That's what my goofy 10,000 foot thick wing was, that would
> >> take off with no airspeed or power. A balloon.
> >
> > You're wrong.
> >
> > The "net downward force" includes the force of gravity. Which is
> > lessened because a gas of lower density..
> >
> > ...I can't believe I have to explain things so basic.
>
> I know, but you have to. Your first attempt didn't appear to include
> unsaid gravity. Gas that you described as "within the balloon" is now
> treated as "part of" the balloon.

Of course gas within the balloon is part of the ballon. Nothing I said
ever implied otherwise.

--
Alan Baker
Vancouver, British Columbia
<http://gallery.me.com/alangbaker/100008/DSCF0162/web.jpg>

[Beryl[_3_]]

Alan Baker wrote:
> In article >,
> Alan Baker > wrote:
>
>> In article >,
>> Beryl > wrote:
>>
>>> Alan Baker wrote:
>>>
>>>> It's true that the exhaust stream doesn't directly push on the inner
>>>> surface of a rocket engine.
>>> Yeah, I like that aerospike design, the inside-out nozzle thing.
>>>
>>>> wing encounters some unmoving air, and the wing then throws the air
>>>> downwards, the velocity of the air has been changed, and the wing
>>>> will experience an upwards reaction force. At the same time, a
>>>> downwash- flow is created.
>>> The wing, remember, is moving forward. "Downwards" is one component of
>>> circulation.
>> Those weren't my words.
>>
>> Yes, but Newton's laws tell us that there is a net force down on the
>> air. No net force down on the air, no net force up on the plane.
>>
>> Force is change of momentum with respect to time.
>
> BTW, the man whom you are contradicting

I don't think I contradicted anything there. Point it out.

> is Scott Eberhardt, Bachelors & Masters Degrees in Aeronautics and Astronautics from MIT, Ph.D. in the
> same field from Stanford, research scientist at the NASA Ames Research
> Center, faculty of the University of Washington.
>
> But... ...really...
>
> <http://books.google.com/books?id=wmuPXQuZnGoC&pg=PT5&lpg=PT5&dq=Scott+Eb
> erhardt+aeronautics+and+astronautics&source=bl&ots=skN-zbDvej&sig=msQ-_Im
> p6t-P62ehNWIld7RRYWs&hl=en&ei=GgEeS4f4AYzStgPB5eiCCg&sa=X&oi=book_result&
> ct=result&resnum=6&ved=0CBsQ6AEwBQ#v=onepage&q=downwash&f=false>
>
> ...what would *HE* know about it compared to you?

Likely a lot, and possibly nothing. I've encountered more than a couple
supposed "authorities" on specific subjects who don't know squat, but
they're masters at bull****ting their ways to lofty titles and
positions. Did you know that a gas cools as it's compressed? One layer
of the atmosphere is called the hemisphere? The stuff in grass that
makes it green is chloroform? A jet fighter cruising straight and level
at high speed experiences tremendous G forces due to the speed?

[Beryl[_3_]]

Alan Baker wrote:
> In article >,
> Beryl > wrote:
>
>> Alan Baker wrote:
>>> In article >,
>>> Beryl > wrote:
>>>
>>>> Alan Baker wrote:
>>>>
>>>>> It's true that the exhaust stream doesn't directly push on the inner
>>>>> surface of a rocket engine.
>>>> Yeah, I like that aerospike design, the inside-out nozzle thing.
>>>>
>>>>> wing encounters some unmoving air, and the wing then throws the air
>>>>> downwards, the velocity of the air has been changed, and the wing
>>>>> will experience an upwards reaction force. At the same time, a
>>>>> downwash- flow is created.
>>>> The wing, remember, is moving forward. "Downwards" is one component of
>>>> circulation.
>>> Those weren't my words.
>> What do you suppose happens to "downwash" when it goes up? Say, pulling
>> positive G force at the top of a loop? Now you lost the surface of the
>> earth, the only thing that, according to you, finally stops it.
>
> The earth still stops it:
>
> Gravity: perhaps you've heard of it?

Gravity is not the earth.

[Beryl[_3_]]

Alan Baker wrote:
> In article >,
> Alan Baker > wrote:
>
>> In article >,
>> Beryl > wrote:
>>
>>> Alan Baker wrote:
>>>
>>>> It's true that the exhaust stream doesn't directly push on the inner
>>>> surface of a rocket engine.
>>> Yeah, I like that aerospike design, the inside-out nozzle thing.
>>>
>>>> wing encounters some unmoving air, and the wing then throws the air
>>>> downwards, the velocity of the air has been changed, and the wing
>>>> will experience an upwards reaction force. At the same time, a
>>>> downwash- flow is created.
>>> The wing, remember, is moving forward. "Downwards" is one component of
>>> circulation.
>> Those weren't my words.
>>
>> Yes, but Newton's laws tell us that there is a net force down on the
>> air. No net force down on the air, no net force up on the plane.
>>
>> Force is change of momentum with respect to time.
>
> BTW, the man whom you are contradicting is Scott Eberhardt, Bachelors &

I wasn't, but I will now.

"...the wing then throws the air downwards" is just plain wrong.
"Downwards" is not a direction that the air was *ever* thrown.

[Alan Baker]

In article >,
Beryl > wrote:

> Alan Baker wrote:
> > In article >,
> > Alan Baker > wrote:
> >
> >> In article >,
> >> Beryl > wrote:
> >>
> >>> Alan Baker wrote:
> >>>
> >>>> It's true that the exhaust stream doesn't directly push on the inner
> >>>> surface of a rocket engine.
> >>> Yeah, I like that aerospike design, the inside-out nozzle thing.
> >>>
> >>>> wing encounters some unmoving air, and the wing then throws the air
> >>>> downwards, the velocity of the air has been changed, and the wing
> >>>> will experience an upwards reaction force. At the same time, a
> >>>> downwash- flow is created.
> >>> The wing, remember, is moving forward. "Downwards" is one component of
> >>> circulation.
> >> Those weren't my words.
> >>
> >> Yes, but Newton's laws tell us that there is a net force down on the
> >> air. No net force down on the air, no net force up on the plane.
> >>
> >> Force is change of momentum with respect to time.
> >
> > BTW, the man whom you are contradicting
>
> I don't think I contradicted anything there. Point it out.
>
> > is Scott Eberhardt, Bachelors & Masters Degrees in Aeronautics and
> > Astronautics from MIT, Ph.D. in the
> > same field from Stanford, research scientist at the NASA Ames Research
> > Center, faculty of the University of Washington.
> >
> > But... ...really...
> >
> > <http://books.google.com/books?id=wmuPXQuZnGoC&pg=PT5&lpg=PT5&dq=Scott+Eb
> > erhardt+aeronautics+and+astronautics&source=bl&ots=skN-zbDvej&sig=msQ-_Im
> > p6t-P62ehNWIld7RRYWs&hl=en&ei=GgEeS4f4AYzStgPB5eiCCg&sa=X&oi=book_result&
> > ct=result&resnum=6&ved=0CBsQ6AEwBQ#v=onepage&q=downwash&f=false>
> >
> > ...what would *HE* know about it compared to you?
>
> Likely a lot, and possibly nothing. I've encountered more than a couple
> supposed "authorities" on specific subjects who don't know squat, but
> they're masters at bull****ting their ways to lofty titles and
> positions. Did you know that a gas cools as it's compressed? One layer
> of the atmosphere is called the hemisphere? The stuff in grass that
> makes it green is chloroform? A jet fighter cruising straight and level
> at high speed experiences tremendous G forces due to the speed?

Sorry, but if I have to trust what you understand versus what he
understands, it isn't even a contest.

And I'd like to see you show just *who* is supposed to have said those
things and whether they are actually educated in the appropriate fields.

--
Alan Baker
Vancouver, British Columbia
<http://gallery.me.com/alangbaker/100008/DSCF0162/web.jpg>

[Alan Baker]

In article >,
Beryl > wrote:

> Alan Baker wrote:
> > In article >,
> > Beryl > wrote:
> >
> >> Alan Baker wrote:
> >>> In article >,
> >>> Beryl > wrote:
> >>>
> >>>> Alan Baker wrote:
> >>>>
> >>>>> It's true that the exhaust stream doesn't directly push on the inner
> >>>>> surface of a rocket engine.
> >>>> Yeah, I like that aerospike design, the inside-out nozzle thing.
> >>>>
> >>>>> wing encounters some unmoving air, and the wing then throws the air
> >>>>> downwards, the velocity of the air has been changed, and the wing
> >>>>> will experience an upwards reaction force. At the same time, a
> >>>>> downwash- flow is created.
> >>>> The wing, remember, is moving forward. "Downwards" is one component of
> >>>> circulation.
> >>> Those weren't my words.
> >> What do you suppose happens to "downwash" when it goes up? Say, pulling
> >> positive G force at the top of a loop? Now you lost the surface of the
> >> earth, the only thing that, according to you, finally stops it.
> >
> > The earth still stops it:
> >
> > Gravity: perhaps you've heard of it?
>
> Gravity is not the earth.

LOL

--
Alan Baker
Vancouver, British Columbia
<http://gallery.me.com/alangbaker/100008/DSCF0162/web.jpg>

[Alan Baker]

In article >,
Beryl > wrote:

> Alan Baker wrote:
> > In article >,
> > Alan Baker > wrote:
> >
> >> In article >,
> >> Beryl > wrote:
> >>
> >>> Alan Baker wrote:
> >>>
> >>>> It's true that the exhaust stream doesn't directly push on the inner
> >>>> surface of a rocket engine.
> >>> Yeah, I like that aerospike design, the inside-out nozzle thing.
> >>>
> >>>> wing encounters some unmoving air, and the wing then throws the air
> >>>> downwards, the velocity of the air has been changed, and the wing
> >>>> will experience an upwards reaction force. At the same time, a
> >>>> downwash- flow is created.
> >>> The wing, remember, is moving forward. "Downwards" is one component of
> >>> circulation.
> >> Those weren't my words.
> >>
> >> Yes, but Newton's laws tell us that there is a net force down on the
> >> air. No net force down on the air, no net force up on the plane.
> >>
> >> Force is change of momentum with respect to time.
> >
> > BTW, the man whom you are contradicting is Scott Eberhardt, Bachelors &
>
> I wasn't, but I will now.
>
> "...the wing then throws the air downwards" is just plain wrong.
> "Downwards" is not a direction that the air was *ever* thrown.

You are incorrect.

The plane experiences a force upwards from the air, therefore (and this
is inescapable basic Newtonian physics) the air experiences a force
downward from the aircraft.

Bachelors and Masters from MIT, Ph.D. from Stanford, all in Aeronautics
and Astronautics, but you know better!

LOL

--
Alan Baker
Vancouver, British Columbia
<http://gallery.me.com/alangbaker/100008/DSCF0162/web.jpg>

[Jim Logajan]

Alan Baker > wrote:
> Jim Logajan > wrote:
>> Alan Baker > wrote:
>> > Look if you think that conservation of *mass* plays any role in
>> > this, you're missing out from the start. It's conservation of
>> > *momentum* that's in play here.
>>
>> It appears you have never studied fluid dynamics (maybe elementary
>> fluid statics?) and I doubt that you own any books on the subject.
>
> Sorry, lad, but conservation of mass is a principle that comes up
> mostly in *chemistry*.

Please don't patronize when you've never studied a subject. A moment's
research would have prevented you from posting something that incredibly
ignorant. You might want to look up the "axioms of fluid dynamics" before
you further add to your public embarrassment.

>> > The aircraft has a force exerted on it equal to its weight. That
>> > means that the aircraft must be exerting a force on the air in the
>> > opposite direction.
>>
>> In other news, 1 + 1 = 2.
>
> What a pity then that you don't understand it.

Shrug - your insults are lame and tiresome, but I will admit you're
patronization is irritating. I do make mistakes about things I was
taught, but I should point out to you that I did well enough in college
physics to earn an undergraduate degree in the subject. Unlike you, I
have had to solve a **** load of problems involving conservation of
momentum to prove I understood the basics - including conservation of
momentum in quantum mechanical systems. So far as I know, you HAVEN'T had
to prove your mastery of the subject with ANYONE.

>> >> (Just FYI, imagine a ~957 kg (Fg ~= 9379 N) helicopter dropped
>> >> from a balloon from 3,000 m altitude (rho ~= 0.83 kg/m^3) and it's
>> >> engine immediately started. After a small drop it levels out and
>> >> maintains a downwash of air moving through its 6 m diameter disk
>> >> (A ~= 28 m^2) at, say, 20 m/s. (So m_dot ~= 469 kg/s and hence Fe
>> >> = Fg.)
>> >>
>> >> It would take ~150 s for that downwash to reach the ground if it
>> >> maintained that speed. In the mean time, once the helicopter
>> >> stopped descending, conservation of mass in an incompressible
>> >> fluid seems to require an equal volume of air to have an upward
>> >> vector of 20 m/s. So the surface of earth appears to be irrelevant
>> >> for over two minutes.)
>> >
>> > Nope.
>>
>> Dang - I try to use real numbers to establish a baseline example, and
>> you manage to use a single word to demolish my attempts! Really
>> helpful mathematical counter-example you produced - not.
>
> No math is necessary for this. Look up "qualitative analysis".

Well that probably explains your problem - you don't know how to set up
the math properly, so you have no way to validate whether your
"qualitative analysis" is correct.

Ironically, all your posts contain the same violation of conservation of
momentum - and yet you keep pointing to that concept as vindication.

>> I don't know what your problem is - maybe you are thinking this is a
>> rocket problem where no external fluids are involved and you can't
>> get your mind around the fact that THIS ISN'T A BLOODY ROCKET
>> PROBLEM. Whatever the case, you seem to be fixated on applying one
>> conservation law to one element in the entire system to the exclusion
>> of everything else.
>
> The law I'm focussed on is the one that counts. It doesn't matter
> whether the fluid is expelled from inside or whether it's an external
> fluid diverted down by the surfaces of the craft.

You can't "focus" on one conservation law because the number of
constraining equations has to equal the number of variables. Doing so
simply leads to an infinite number of bogus results.

> In order for there to be a continuous force W equaling the weight of
> the craft acting on it, the craft must exert a force -W on the fluid.
> That -W means that there is a downward change of momentum in the
> fluid.

Sigh. This is a case where a little knowledge is a dangerous thing. It
would take a book to explain the problem with your conceptual view of
fluid dynamics. I don't have that sort of patience.

> Since the fluid is no accelerated indefinitely, there must be a
> continuous flow (mass per unit time M/t) of the fluid accelerated to a
> velocity V where the equation looks like:
>
> -W = M/t * V

Of course if you had read my earlier post you'd see I'd ALREADY USED THAT
EQUATION. But you obviously aren't familiar with the conventions used in
fluid dynamics, so you probably had no clue what my "m_dot" meant or how
I got the figures I did.

> The velocity of the fluid will be:
>
> V = -W/(M/t)
> That is inescapable. If the craft weighs 9800N (newtons), and it moves
> 100kg of air every second, then the air must be moving downward (net,
> now!) at 98 m/s.

You math is correct and no one has denied there is a downwash (why you
think otherwise continues to baffle me) yet your "net, now" comment
violates conservation of momentum.

Here's why:

If we choose a reference frame so that at T=0 everything in the system is
stationary with respect to that frame, we set the net momentum of the
system to 0. Then, so long as the system remains closed, at all other
times the conservation of momentum must yield 0.

But according to your "qualitative analysis" the net vertical momentum
P_net_z increases with time T, like so:

P_net_z(T) = (100 kg/s)*T*V

That's because the earth and the airplane maintain zero vertical
momentums (P_earth_z(T) = 0, P_plane_z(T) = 0,) and there appears to be
nothing in your conceptual view of the situation to correct that
violation of conservation of momentum.

> I'm sorry if you don't get this, but it is very simple and absolutely
> irrefutable.

It appears to salve your ego to ascribe assertions to me that I never
made and then tell the world that those falsehoods prove I don't "get
it." Probably because you've grown so much hubris and so little humility.

[Beryl[_3_]]

Alan Baker wrote:
> In article >,
> Beryl > wrote:
>
>> Alan Baker wrote:
>>> In article >,
>>> Alan Baker > wrote:
>>>
>>>> In article >,
>>>> Beryl > wrote:
>>>>
>>>>> Alan Baker wrote:
>>>>>
>>>>>> It's true that the exhaust stream doesn't directly push on the inner
>>>>>> surface of a rocket engine.
>>>>> Yeah, I like that aerospike design, the inside-out nozzle thing.
>>>>>
>>>>>> wing encounters some unmoving air, and the wing then throws the air
>>>>>> downwards, the velocity of the air has been changed, and the wing
>>>>>> will experience an upwards reaction force. At the same time, a
>>>>>> downwash- flow is created.
>>>>> The wing, remember, is moving forward. "Downwards" is one component of
>>>>> circulation.
>>>> Those weren't my words.
>>>>
>>>> Yes, but Newton's laws tell us that there is a net force down on the
>>>> air. No net force down on the air, no net force up on the plane.
>>>>
>>>> Force is change of momentum with respect to time.
>>> BTW, the man whom you are contradicting
>> I don't think I contradicted anything there. Point it out.
>>
>>> is Scott Eberhardt, Bachelors & Masters Degrees in Aeronautics and
>>> Astronautics from MIT, Ph.D. in the
>>> same field from Stanford, research scientist at the NASA Ames Research
>>> Center, faculty of the University of Washington.
>>>
>>> But... ...really...
>>>
>>> <http://books.google.com/books?id=wmuPXQuZnGoC&pg=PT5&lpg=PT5&dq=Scott+Eb
>>> erhardt+aeronautics+and+astronautics&source=bl&ots=skN-zbDvej&sig=msQ-_Im
>>> p6t-P62ehNWIld7RRYWs&hl=en&ei=GgEeS4f4AYzStgPB5eiCCg&sa=X&oi=book_result&
>>> ct=result&resnum=6&ved=0CBsQ6AEwBQ#v=onepage&q=downwash&f=false>
>>>
>>> ...what would *HE* know about it compared to you?
>> Likely a lot, and possibly nothing. I've encountered more than a couple
>> supposed "authorities" on specific subjects who don't know squat, but
>> they're masters at bull****ting their ways to lofty titles and
>> positions. Did you know that a gas cools as it's compressed? One layer
>> of the atmosphere is called the hemisphere? The stuff in grass that
>> makes it green is chloroform? A jet fighter cruising straight and level
>> at high speed experiences tremendous G forces due to the speed?
>
> Sorry, but if I have to trust what you understand versus what he
> understands, it isn't even a contest.

Of course.

> And I'd like to see you show just *who* is supposed to have said those
> things and whether they are actually educated in the appropriate fields.

Those examples are all from one of my A&P school's Master Instructors.
That's the title bestowed upon those at the top. Master Instructors
receive the highest pay, and are qualified to teach any and all of the
classes. He came from the U.S. Navy, where he was a maintenance instructor.

[Alan Baker]

In article >,
Beryl > wrote:

> Alan Baker wrote:
> > In article >,
> > Beryl > wrote:
> >
> >> Alan Baker wrote:
> >>> In article >,
> >>> Alan Baker > wrote:
> >>>
> >>>> In article >,
> >>>> Beryl > wrote:
> >>>>
> >>>>> Alan Baker wrote:
> >>>>>
> >>>>>> It's true that the exhaust stream doesn't directly push on the inner
> >>>>>> surface of a rocket engine.
> >>>>> Yeah, I like that aerospike design, the inside-out nozzle thing.
> >>>>>
> >>>>>> wing encounters some unmoving air, and the wing then throws the air
> >>>>>> downwards, the velocity of the air has been changed, and the wing
> >>>>>> will experience an upwards reaction force. At the same time, a
> >>>>>> downwash- flow is created.
> >>>>> The wing, remember, is moving forward. "Downwards" is one component of
> >>>>> circulation.
> >>>> Those weren't my words.
> >>>>
> >>>> Yes, but Newton's laws tell us that there is a net force down on the
> >>>> air. No net force down on the air, no net force up on the plane.
> >>>>
> >>>> Force is change of momentum with respect to time.
> >>> BTW, the man whom you are contradicting
> >> I don't think I contradicted anything there. Point it out.
> >>
> >>> is Scott Eberhardt, Bachelors & Masters Degrees in Aeronautics and
> >>> Astronautics from MIT, Ph.D. in the
> >>> same field from Stanford, research scientist at the NASA Ames Research
> >>> Center, faculty of the University of Washington.
> >>>
> >>> But... ...really...
> >>>
> >>> <http://books.google.com/books?id=wmuPXQuZnGoC&pg=PT5&lpg=PT5&dq=Scott+Eb
> >>> erhardt+aeronautics+and+astronautics&source=bl&ots=skN-zbDvej&sig=msQ-_Im
> >>> p6t-P62ehNWIld7RRYWs&hl=en&ei=GgEeS4f4AYzStgPB5eiCCg&sa=X&oi=book_result&
> >>> ct=result&resnum=6&ved=0CBsQ6AEwBQ#v=onepage&q=downwash&f=false>
> >>>
> >>> ...what would *HE* know about it compared to you?
> >> Likely a lot, and possibly nothing. I've encountered more than a couple
> >> supposed "authorities" on specific subjects who don't know squat, but
> >> they're masters at bull****ting their ways to lofty titles and
> >> positions. Did you know that a gas cools as it's compressed? One layer
> >> of the atmosphere is called the hemisphere? The stuff in grass that
> >> makes it green is chloroform? A jet fighter cruising straight and level
> >> at high speed experiences tremendous G forces due to the speed?
> >
> > Sorry, but if I have to trust what you understand versus what he
> > understands, it isn't even a contest.
>
> Of course.
>
> > And I'd like to see you show just *who* is supposed to have said those
> > things and whether they are actually educated in the appropriate fields.
>
> Those examples are all from one of my A&P school's Master Instructors.

And your comparing an Airframe & Power instructor to a Ph.D. in
Aeronautics...

LOL

BTW, there is nothing exceptional about the answers to questions that
aren't even in his field being wrong.

> That's the title bestowed upon those at the top. Master Instructors
> receive the highest pay, and are qualified to teach any and all of the
> classes. He came from the U.S. Navy, where he was a maintenance instructor.

Great. That doesn't mean he knows anything about physics and fluid
dynamics. Being a Ph.D. in Aeronautics, OTOH...

--
Alan Baker
Vancouver, British Columbia
<http://gallery.me.com/alangbaker/100008/DSCF0162/web.jpg>

[Alan Baker]

In article >,
Jim Logajan > wrote:

> Alan Baker > wrote:
> > Jim Logajan > wrote:
> >> Alan Baker > wrote:
> >> > Look if you think that conservation of *mass* plays any role in
> >> > this, you're missing out from the start. It's conservation of
> >> > *momentum* that's in play here.
> >>
> >> It appears you have never studied fluid dynamics (maybe elementary
> >> fluid statics?) and I doubt that you own any books on the subject.
> >
> > Sorry, lad, but conservation of mass is a principle that comes up
> > mostly in *chemistry*.
>
> Please don't patronize when you've never studied a subject. A moment's
> research would have prevented you from posting something that incredibly
> ignorant. You might want to look up the "axioms of fluid dynamics" before
> you further add to your public embarrassment.

I'm not the least embarrassed, because I know what "axiom" actually
means.

>
> >> > The aircraft has a force exerted on it equal to its weight. That
> >> > means that the aircraft must be exerting a force on the air in the
> >> > opposite direction.
> >>
> >> In other news, 1 + 1 = 2.
> >
> > What a pity then that you don't understand it.
>
> Shrug - your insults are lame and tiresome, but I will admit you're
> patronization is irritating. I do make mistakes about things I was
> taught, but I should point out to you that I did well enough in college
> physics to earn an undergraduate degree in the subject. Unlike you, I
> have had to solve a **** load of problems involving conservation of
> momentum to prove I understood the basics - including conservation of
> momentum in quantum mechanical systems. So far as I know, you HAVEN'T had
> to prove your mastery of the subject with ANYONE.

Conservation of linear momentum is another of the axioms of fluid
dynamics, lad.

>
> >> >> (Just FYI, imagine a ~957 kg (Fg ~= 9379 N) helicopter dropped
> >> >> from a balloon from 3,000 m altitude (rho ~= 0.83 kg/m^3) and it's
> >> >> engine immediately started. After a small drop it levels out and
> >> >> maintains a downwash of air moving through its 6 m diameter disk
> >> >> (A ~= 28 m^2) at, say, 20 m/s. (So m_dot ~= 469 kg/s and hence Fe
> >> >> = Fg.)
> >> >>
> >> >> It would take ~150 s for that downwash to reach the ground if it
> >> >> maintained that speed. In the mean time, once the helicopter
> >> >> stopped descending, conservation of mass in an incompressible
> >> >> fluid seems to require an equal volume of air to have an upward
> >> >> vector of 20 m/s. So the surface of earth appears to be irrelevant
> >> >> for over two minutes.)
> >> >
> >> > Nope.
> >>
> >> Dang - I try to use real numbers to establish a baseline example, and
> >> you manage to use a single word to demolish my attempts! Really
> >> helpful mathematical counter-example you produced - not.
> >
> > No math is necessary for this. Look up "qualitative analysis".
>
> Well that probably explains your problem - you don't know how to set up
> the math properly, so you have no way to validate whether your
> "qualitative analysis" is correct.

I do know how to set up the math properly. I've known since I was about
17.

>
> Ironically, all your posts contain the same violation of conservation of
> momentum - and yet you keep pointing to that concept as vindication.

Nope.

>
> >> I don't know what your problem is - maybe you are thinking this is a
> >> rocket problem where no external fluids are involved and you can't
> >> get your mind around the fact that THIS ISN'T A BLOODY ROCKET
> >> PROBLEM. Whatever the case, you seem to be fixated on applying one
> >> conservation law to one element in the entire system to the exclusion
> >> of everything else.
> >
> > The law I'm focussed on is the one that counts. It doesn't matter
> > whether the fluid is expelled from inside or whether it's an external
> > fluid diverted down by the surfaces of the craft.
>
> You can't "focus" on one conservation law because the number of
> constraining equations has to equal the number of variables. Doing so
> simply leads to an infinite number of bogus results.

Actually, you're wrong.

>
> > In order for there to be a continuous force W equaling the weight of
> > the craft acting on it, the craft must exert a force -W on the fluid.
> > That -W means that there is a downward change of momentum in the
> > fluid.
>
> Sigh. This is a case where a little knowledge is a dangerous thing. It
> would take a book to explain the problem with your conceptual view of
> fluid dynamics. I don't have that sort of patience.

Fluid dynamics isn't even an issue here. Force and momentum are.

The aircraft experiences a force from the air and therefore MUSR impart
a force on the air.

Force IS change of momentum with respect to time.

>
> > Since the fluid is no accelerated indefinitely, there must be a
> > continuous flow (mass per unit time M/t) of the fluid accelerated to a
> > velocity V where the equation looks like:
> >
> > -W = M/t * V
>
> Of course if you had read my earlier post you'd see I'd ALREADY USED THAT
> EQUATION. But you obviously aren't familiar with the conventions used in
> fluid dynamics, so you probably had no clue what my "m_dot" meant or how
> I got the figures I did.
>
> > The velocity of the fluid will be:
> >
> > V = -W/(M/t)
> > That is inescapable. If the craft weighs 9800N (newtons), and it moves
> > 100kg of air every second, then the air must be moving downward (net,
> > now!) at 98 m/s.
>
> You math is correct and no one has denied there is a downwash (why you
> think otherwise continues to baffle me) yet your "net, now" comment
> violates conservation of momentum.

It doesn't. You're simply wrong. The momentum of the system as a whole
remains constant, but the air gets some downward momentum, which is only
netted out when it finally gets transferred to the earth (which has some
upward momentum from the plane's gravity pulling up on it).

>
> Here's why:
>
> If we choose a reference frame so that at T=0 everything in the system is
> stationary with respect to that frame, we set the net momentum of the
> system to 0. Then, so long as the system remains closed, at all other
> times the conservation of momentum must yield 0.

We cannot choose a reference frame where everything is stationary with
respect to it. The aircraft is moving with respect to the air.

>
> But according to your "qualitative analysis" the net vertical momentum
> P_net_z increases with time T, like so:
>
> P_net_z(T) = (100 kg/s)*T*V

Only if you ignore the upward momentum of the earth. The earth is part
of the system, too.

>
> That's because the earth and the airplane maintain zero vertical
> momentums (P_earth_z(T) = 0, P_plane_z(T) = 0,) and there appears to be
> nothing in your conceptual view of the situation to correct that
> violation of conservation of momentum.

Only because you're ignoring the upward momentum of the earth.

>
> > I'm sorry if you don't get this, but it is very simple and absolutely
> > irrefutable.
>
> It appears to salve your ego to ascribe assertions to me that I never
> made and then tell the world that those falsehoods prove I don't "get
> it." Probably because you've grown so much hubris and so little humility.

LOL

--
Alan Baker
Vancouver, British Columbia
<http://gallery.me.com/alangbaker/100008/DSCF0162/web.jpg>

[Beryl[_3_]]

Alan Baker wrote:
> In article >,
> Beryl > wrote:
>
>> Alan Baker wrote:
>>> In article >,
>>> Alan Baker > wrote:
>>>
>>>> In article >,
>>>> Beryl > wrote:
>>>>
>>>>> Alan Baker wrote:
>>>>>
>>>>>> It's true that the exhaust stream doesn't directly push on the inner
>>>>>> surface of a rocket engine.
>>>>> Yeah, I like that aerospike design, the inside-out nozzle thing.
>>>>>
>>>>>> wing encounters some unmoving air, and the wing then throws the air
>>>>>> downwards, the velocity of the air has been changed, and the wing
>>>>>> will experience an upwards reaction force. At the same time, a
>>>>>> downwash- flow is created.
>>>>> The wing, remember, is moving forward. "Downwards" is one component of
>>>>> circulation.
>>>> Those weren't my words.
>>>>
>>>> Yes, but Newton's laws tell us that there is a net force down on the
>>>> air. No net force down on the air, no net force up on the plane.
>>>>
>>>> Force is change of momentum with respect to time.
>>> BTW, the man whom you are contradicting is Scott Eberhardt, Bachelors &
>> I wasn't, but I will now.
>>
>> "...the wing then throws the air downwards" is just plain wrong.
>> "Downwards" is not a direction that the air was *ever* thrown.
>
> You are incorrect.
>
> The plane experiences a force upwards from the air, therefore (and this
> is inescapable basic Newtonian physics) the air experiences a force
> downward from the aircraft.

Up, down, forward, backward.
Lift, weight, thrust, drag.
We always see those four simple arrows.
"If a wing encounters some unmoving air, and the wing then throws the
air downwards" is dumbed down. The air isn't thrown downwards.
Illustrations of the flow around a wing in a wind tunnel are misleading
too. You see all the air going from left to right, every time. No
circulation. Air is pushed the other way, from right to left, under the
wing. Did everyone forget that?

> Bachelors and Masters from MIT, Ph.D. from Stanford, all in Aeronautics
> and Astronautics, but you know better!

"Those weren't my words." You didn't have enough confidence in Mr.
Bachelors and Masters from MIT, Ph.D. from Stanford's words to defend them.

> LOL

Exactly. Eberhardt's credentials made up your mind for you.

[Beryl[_3_]]

Alan Baker wrote:
> In article >,
> Beryl > wrote:
>
>> Alan Baker wrote:
>>> In article >,
>>> Beryl > wrote:
>>>
>>>> Alan Baker wrote:
>>>>> In article >,
>>>>> Beryl > wrote:
>>>>>
>>>>>> Alan Baker wrote:
>>>>>>
>>>>>>> It's true that the exhaust stream doesn't directly push on the inner
>>>>>>> surface of a rocket engine.
>>>>>> Yeah, I like that aerospike design, the inside-out nozzle thing.
>>>>>>
>>>>>>> wing encounters some unmoving air, and the wing then throws the air
>>>>>>> downwards, the velocity of the air has been changed, and the wing
>>>>>>> will experience an upwards reaction force. At the same time, a
>>>>>>> downwash- flow is created.
>>>>>> The wing, remember, is moving forward. "Downwards" is one component of
>>>>>> circulation.
>>>>> Those weren't my words.
>>>> What do you suppose happens to "downwash" when it goes up? Say, pulling
>>>> positive G force at the top of a loop? Now you lost the surface of the
>>>> earth, the only thing that, according to you, finally stops it.
>>> The earth still stops it:
>>>
>>> Gravity: perhaps you've heard of it?
>> Gravity is not the earth.
>
> LOL

You're stuck in one dimension. Up, down. A line.

[Alan Baker]

In article >,
Beryl > wrote:
> >>>>>> It's true that the exhaust stream doesn't directly push on the inner
> >>>>>> surface of a rocket engine.
> >>>>> Yeah, I like that aerospike design, the inside-out nozzle thing.
> >>>>>
> >>>>>> wing encounters some unmoving air, and the wing then throws the air
> >>>>>> downwards, the velocity of the air has been changed, and the wing
> >>>>>> will experience an upwards reaction force. At the same time, a
> >>>>>> downwash- flow is created.
> >>>>> The wing, remember, is moving forward. "Downwards" is one component of
> >>>>> circulation.
> >>>> Those weren't my words.
> >>>>
> >>>> Yes, but Newton's laws tell us that there is a net force down on the
> >>>> air. No net force down on the air, no net force up on the plane.
> >>>>
> >>>> Force is change of momentum with respect to time.
> >>> BTW, the man whom you are contradicting is Scott Eberhardt, Bachelors &
> >> I wasn't, but I will now.
> >>
> >> "...the wing then throws the air downwards" is just plain wrong.
> >> "Downwards" is not a direction that the air was *ever* thrown.
> >
> > You are incorrect.
> >
> > The plane experiences a force upwards from the air, therefore (and this
> > is inescapable basic Newtonian physics) the air experiences a force
> > downward from the aircraft.
>
> Up, down, forward, backward.
> Lift, weight, thrust, drag.
> We always see those four simple arrows.
> "If a wing encounters some unmoving air, and the wing then throws the
> air downwards" is dumbed down. The air isn't thrown downwards.
> Illustrations of the flow around a wing in a wind tunnel are misleading
> too. You see all the air going from left to right, every time. No
> circulation. Air is pushed the other way, from right to left, under the
> wing. Did everyone forget that?

The air is thrown down. It has to be. For the aircraft to experience an
upward force from the air, the air must experience a downward force from
the plane. That downward force isn't balanced by any other force on the
air, so it must result in the air being moved (or "thrown") downward.

>
> > Bachelors and Masters from MIT, Ph.D. from Stanford, all in Aeronautics
> > and Astronautics, but you know better!
>
> "Those weren't my words." You didn't have enough confidence in Mr.
> Bachelors and Masters from MIT, Ph.D. from Stanford's words to defend them.

They don't need defense.

>
> > LOL
>
> Exactly. Eberhardt's credentials made up your mind for you.

Nope. I understood the situation long before I'd ever even read his
article.

--
Alan Baker
Vancouver, British Columbia
<http://gallery.me.com/alangbaker/100008/DSCF0162/web.jpg>

[Alan Baker]

In article >,
Beryl > wrote:

> Alan Baker wrote:
> > In article >,
> > Beryl > wrote:
> >
> >> Alan Baker wrote:
> >>> In article >,
> >>> Beryl > wrote:
> >>>
> >>>> Alan Baker wrote:
> >>>>> In article >,
> >>>>> Beryl > wrote:
> >>>>>
> >>>>>> Alan Baker wrote:
> >>>>>>
> >>>>>>> It's true that the exhaust stream doesn't directly push on the inner
> >>>>>>> surface of a rocket engine.
> >>>>>> Yeah, I like that aerospike design, the inside-out nozzle thing.
> >>>>>>
> >>>>>>> wing encounters some unmoving air, and the wing then throws the air
> >>>>>>> downwards, the velocity of the air has been changed, and the wing
> >>>>>>> will experience an upwards reaction force. At the same time, a
> >>>>>>> downwash- flow is created.
> >>>>>> The wing, remember, is moving forward. "Downwards" is one component of
> >>>>>> circulation.
> >>>>> Those weren't my words.
> >>>> What do you suppose happens to "downwash" when it goes up? Say, pulling
> >>>> positive G force at the top of a loop? Now you lost the surface of the
> >>>> earth, the only thing that, according to you, finally stops it.
> >>> The earth still stops it:
> >>>
> >>> Gravity: perhaps you've heard of it?
> >> Gravity is not the earth.
> >
> > LOL
>
> You're stuck in one dimension. Up, down. A line.

LOL

You're stuck in fantasy land if you believe that an unbalanced force can
do anything but cause the air around the plane to move down.

--
Alan Baker
Vancouver, British Columbia
<http://gallery.me.com/alangbaker/100008/DSCF0162/web.jpg>

[Morgans[_2_]]

"Alan Baker" > wrote >

> Look up "Conservation of Momentum" and get back to me.

I've been polite as long as I can stand it.

HEY DUMBASS ! Get out of the textbook, and into the real world.

You completely ignore the real world effects of friction. That is a hint,
to where the momentum eventually goes to.

You push a car on perfectly level ground. It does not roll forever. What
happened to conservation of momentum?

Same thing with your stupid downflow hits the earth argument. Friction
kills that wave off in relatively short order, dumbass. Get real.

Group, I am sorry for my tone, and for biting on this not too smart troll.
I'll be good now.
--
Jim in NC

[Alan Baker]

In article >,
"Morgans" > wrote:

> "Alan Baker" > wrote >
>
> > Look up "Conservation of Momentum" and get back to me.
>
> I've been polite as long as I can stand it.
>
> HEY DUMBASS ! Get out of the textbook, and into the real world.
>
> You completely ignore the real world effects of friction. That is a hint,
> to where the momentum eventually goes to.

No. That's not where momentum eventually goes to.

>
> You push a car on perfectly level ground. It does not roll forever. What
> happened to conservation of momentum?

It's momentum is transferred to the ground and air by friction.

But momentum is conserved.

>
> Same thing with your stupid downflow hits the earth argument. Friction
> kills that wave off in relatively short order, dumbass. Get real.

Nope. Friction just spreads it around.

>
> Group, I am sorry for my tone, and for biting on this not too smart troll.
> I'll be good now.

You'll be wrong, though.

--
Alan Baker
Vancouver, British Columbia
<http://gallery.me.com/alangbaker/100008/DSCF0162/web.jpg>

[Beryl[_3_]]

Alan Baker wrote:

> And your comparing an Airframe & Power instructor to a Ph.D. in
> Aeronautics...
>
> LOL

I didn't compare him to anyone.

> BTW, there is nothing exceptional about the answers to questions that
> aren't even in his field being wrong.

Most weren't answers, nobody asked.

>> That's the title bestowed upon those at the top. Master Instructors
>> receive the highest pay, and are qualified to teach any and all of the
>> classes. He came from the U.S. Navy, where he was a maintenance instructor.
>
> Great. That doesn't mean he knows anything about physics and fluid
> dynamics. Being a Ph.D. in Aeronautics, OTOH...

I didn't say he knew much about physics. He was assumed to, required to,
but didn't.

[Beryl[_3_]]

Alan Baker wrote:

>> "Those weren't my words." You didn't have enough confidence in Mr.
>> Bachelors and Masters from MIT, Ph.D. from Stanford's words to defend them.
>
> They don't need defense.

But you weren't sure yesterday, so you needed it?

I found your airplane! It's all about downwash.
http://www.amvaircraft.com/html/gallery_2.html

[Beryl[_3_]]

Alan Baker wrote:
> Beryl > wrote:
...
>>>> Right. And I can push against the hill across the road with my
>>>> voice. Not much, but enough to move the diaphragm in a
>>>> microphone over there, in a split second. The air expelled from
>>>> lungs is never going to make it across the road.
>>>
>>> No, sorry. You don't push the hill with your voice.
>>
>> Of course I do.
>>
>>> The pressure waves contain both positive and negative phases.
>>
>> So you think that a positive won't push because a negative will be
>> coming along shortly?
>
> I think their will be no net push, yes.
>
> See the difference: sound waves, no net flow: no net push.

Sound waves, no net flow: more push than I can apply to the hill across
the road.

http://www.tech-faq.com/acoustic-levitation.shtml
http://science.howstuffworks.com/acoustic-levitation2.htm
http://en.wikipedia.org/wiki/Acoustic_levitation

[Alan Baker]

In article >,
Beryl > wrote:

> Alan Baker wrote:
>
> > And your comparing an Airframe & Power instructor to a Ph.D. in
> > Aeronautics...
> >
> > LOL
>
> I didn't compare him to anyone.

Yes, you did. You suggest that since an A&P instructor could have some
misconceptions about physics that a Ph.D. in Aeronautics would as well.

>
> > BTW, there is nothing exceptional about the answers to questions that
> > aren't even in his field being wrong.
>
> Most weren't answers, nobody asked.

LOL

>
> >> That's the title bestowed upon those at the top. Master Instructors
> >> receive the highest pay, and are qualified to teach any and all of the
> >> classes. He came from the U.S. Navy, where he was a maintenance instructor.
> >
> > Great. That doesn't mean he knows anything about physics and fluid
> > dynamics. Being a Ph.D. in Aeronautics, OTOH...
>
> I didn't say he knew much about physics. He was assumed to, required to,
> but didn't.

And this affects the credibility of an actual Ph.D. in the field, how?

--
Alan Baker
Vancouver, British Columbia
<http://gallery.me.com/alangbaker/100008/DSCF0162/web.jpg>

[Beryl[_3_]]

Alan Baker wrote:
> In article >,
> Beryl > wrote:
>
>> Alan Baker wrote:
>>
>>> And your comparing an Airframe & Power instructor to a Ph.D. in
>>> Aeronautics...
>>>
>>> LOL
>> I didn't compare him to anyone.
>
> Yes, you did. You suggest that since an A&P instructor could

Would.

> have some misconceptions about physics that a Ph.D. in Aeronautics would as well.

Could as well.

You made "could" and "would" switch positions. Not by accident. You're
simply dishonest.

[Alan Baker]

In article >,
Beryl > wrote:

> Alan Baker wrote:
> > In article >,
> > Beryl > wrote:
> >
> >> Alan Baker wrote:
> >>
> >>> And your comparing an Airframe & Power instructor to a Ph.D. in
> >>> Aeronautics...
> >>>
> >>> LOL
> >> I didn't compare him to anyone.
> >
> > Yes, you did. You suggest that since an A&P instructor could
>
> Would.
>
> > have some misconceptions about physics that a Ph.D. in Aeronautics would as
> > well.
>
> Could as well.
>
> You made "could" and "would" switch positions. Not by accident. You're
> simply dishonest.

LOL

--
Alan Baker
Vancouver, British Columbia
<http://gallery.me.com/alangbaker/100008/DSCF0162/web.jpg>

[Beryl[_3_]]

Alan Baker wrote:
> In article >,
> Beryl > wrote:
>
>> Alan Baker wrote:
>>> In article >,
>>> Beryl > wrote:
>>>
>>>> Alan Baker wrote:
>>>>
>>>>> And your comparing an Airframe & Power instructor to a Ph.D. in
>>>>> Aeronautics...
>>>>>
>>>>> LOL
>>>> I didn't compare him to anyone.
>>> Yes, you did. You suggest that since an A&P instructor could
>> Would.
>>
>>> have some misconceptions about physics that a Ph.D. in Aeronautics would as
>>> well.
>> Could as well.
>>
>> You made "could" and "would" switch positions. Not by accident. You're
>> simply dishonest.
>
> LOL

Step-by-step now, just for Alan.

A = An A&P guy is a dummy
B = A PhD guy could be a dummy as well


A and B
That's it, my statement.


if A then B
A, therefore B
That's your understanding of it.

[Beryl[_3_]]

Beryl wrote:
> Alan Baker wrote:
>> In article >,
>> Beryl > wrote:
>>
>>> Alan Baker wrote:
>>>> In article >,
>>>> Beryl > wrote:
>>>>
>>>>> Alan Baker wrote:
>>>>>
>>>>>> And your comparing an Airframe & Power instructor to a
>>>>>> Ph.D. in Aeronautics...
>>>>>>
>>>>>> LOL
>>>>> I didn't compare him to anyone.
>>>> Yes, you did. You suggest that since an A&P instructor could
>>> Would.
>>>
>>>> have some misconceptions about physics that a Ph.D. in
>>>> Aeronautics would as well.
>>> Could as well.
>>>
>>> You made "could" and "would" switch positions. Not by accident.
>>> You're simply dishonest.
>>
>> LOL
>
> Step-by-step now, just for Alan.

No, it's worse than I thought.


> A = An A&P guy is a dummy
> B = A PhD guy could be a dummy as well
C = An A&P guy could be a dummy
D = A PhD guy is a dummy

> A and B That's it, my statement.


if C then D
C therefore D
> That's your understanding of it.

[Alan Baker]

In article >,
Beryl > wrote:

> Alan Baker wrote:
> > In article >,
> > Beryl > wrote:
> >
> >> Alan Baker wrote:
> >>> In article >,
> >>> Beryl > wrote:
> >>>
> >>>> Alan Baker wrote:
> >>>>
> >>>>> And your comparing an Airframe & Power instructor to a Ph.D. in
> >>>>> Aeronautics...
> >>>>>
> >>>>> LOL
> >>>> I didn't compare him to anyone.
> >>> Yes, you did. You suggest that since an A&P instructor could
> >> Would.
> >>
> >>> have some misconceptions about physics that a Ph.D. in Aeronautics would
> >>> as
> >>> well.
> >> Could as well.
> >>
> >> You made "could" and "would" switch positions. Not by accident. You're
> >> simply dishonest.
> >
> > LOL
>
> Step-by-step now, just for Alan.
>
> A = An A&P guy is a dummy

An A&P is uninformed in an area outside is area of training and
expertise.

> B = A PhD guy could be a dummy as well

But you think that a Ph.D. in aeronautics doesn't understand...

....aeronautics.

>
>
> A and B
> That's it, my statement.
>
>
> if A then B
> A, therefore B
> That's your understanding of it.

Nope.

--
Alan Baker
Vancouver, British Columbia
<http://gallery.me.com/alangbaker/100008/DSCF0162/web.jpg>

[Alan Baker]

In article >,
Beryl > wrote:

> Beryl wrote:
> > Alan Baker wrote:
> >> In article >,
> >> Beryl > wrote:
> >>
> >>> Alan Baker wrote:
> >>>> In article >,
> >>>> Beryl > wrote:
> >>>>
> >>>>> Alan Baker wrote:
> >>>>>
> >>>>>> And your comparing an Airframe & Power instructor to a
> >>>>>> Ph.D. in Aeronautics...
> >>>>>>
> >>>>>> LOL
> >>>>> I didn't compare him to anyone.
> >>>> Yes, you did. You suggest that since an A&P instructor could
> >>> Would.
> >>>
> >>>> have some misconceptions about physics that a Ph.D. in
> >>>> Aeronautics would as well.
> >>> Could as well.
> >>>
> >>> You made "could" and "would" switch positions. Not by accident.
> >>> You're simply dishonest.
> >>
> >> LOL
> >
> > Step-by-step now, just for Alan.
>
> No, it's worse than I thought.
>
>
> > A = An A&P guy is a dummy
> > B = A PhD guy could be a dummy as well
> C = An A&P guy could be a dummy
> D = A PhD guy is a dummy
>
> > A and B That's it, my statement.
>
>
> if C then D
> C therefore D
> > That's your understanding of it.

LOL

--
Alan Baker
Vancouver, British Columbia
<http://gallery.me.com/alangbaker/100008/DSCF0162/web.jpg>

[Alan Baker]

In article >,
Beryl > wrote:

> Alan Baker wrote:
>
> > An A&P is uninformed in an area outside is area of training and
> > expertise.
>
> The examples (other than chloroform in grass) were well inside his area
> of training. He holds an A&P Certificate. It's FAA test material. The
> stuff he goofs up on is the stuff that he's teaching A&P students. You
> want your airplane repaired by someone who narrowly squeaked by his
> exams with a 70% score?

You really are a ninny aren't you? Learning about chloroform as it
pertains to aircraft doesn't teach you a thing about plants and what
they actually contain.

>
> And the Navy didn't do any better with him.
>
> So, just like A&P Master Instructors, and their students, and their
> students on down the line, the Ph.D.s among us may be every bit as good
> as those they learned from.

This is about you suggesting that because you once knew an A&P
instructor who spouted off a lot of foolishness outside his areas of
training and expertise, that therefore a Ph.D. in aeronautics won't
(alright "might not") understand aeronautics.

And it's laughable.

--
Alan Baker
Vancouver, British Columbia
<http://gallery.me.com/alangbaker/100008/DSCF0162/web.jpg>

[Beryl[_3_]]

Alan Baker wrote:

> An A&P is uninformed in an area outside is area of training and
> expertise.

The examples (other than chloroform in grass) were well inside his area
of training. He holds an A&P Certificate. It's FAA test material. The
stuff he goofs up on is the stuff that he's teaching A&P students. You
want your airplane repaired by someone who narrowly squeaked by his
exams with a 70% score?

And the Navy didn't do any better with him.

So, just like A&P Master Instructors, and their students, and their
students on down the line, the Ph.D.s among us may be every bit as good
as those they learned from.

[Beryl[_3_]]

Alan Baker wrote:
> In article >, Beryl
> > wrote:
>
>> Alan Baker wrote:
>>
>>> An A&P is uninformed in an area outside is area of training and
>>> expertise.
>> The examples (other than chloroform in grass) were well inside
^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^

Dip**** focuses on chloroform:

> You really are a ninny aren't you? Learning about chloroform as it
> pertains to aircraft

[Alan Baker]

In article >,
Beryl > wrote:

> Alan Baker wrote:
> > In article >, Beryl
> > > wrote:
> >
> >> Alan Baker wrote:
> >>
> >>> An A&P is uninformed in an area outside is area of training and
> >>> expertise.
> >> The examples (other than chloroform in grass) were well inside
> ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^
>
> Dip**** focuses on chloroform:
>
> > You really are a ninny aren't you? Learning about chloroform as it
> > pertains to aircraft

Names for layers of the atmosphere is not something that one would need
to learn as an A&P, nor is it important to know what happens to a gas as
it is compressed.

None of your examples were of a person making basic mistakes *within*
his area of expertise.

--
Alan Baker
Vancouver, British Columbia
<http://gallery.me.com/alangbaker/100008/DSCF0162/web.jpg>

[Steve Hix[_2_]]

> Alan Baker wrote:
>
> > An A&P is uninformed in an area outside is area of training and
> > expertise.

That's a remarkably ignorant statement Alan; you can't possibly know
what areas of information any given individual might or might not have
studied and mastered in addition to earning an A&P rating.

Backpedalling and trying to save yourself by holding up "...is area of
training and expertise...", by the way, won't help you here. You're the
one who circumscribed your argument by limiting it to holders of an A&P
rating, and by implication that they understand nothing outside that
area.

You're not dealing here with sociopath trolls infesting a computer
advocacy newsgroup, you can't slide by with the same sort of
intellectually limp and limited argumentation.

[Beryl[_3_]]

Alan Baker wrote:
> In article >, Beryl
> > wrote:
>
>> Alan Baker wrote:
>>> In article >,
>>> Beryl > wrote:
>>>
>>>> Alan Baker wrote:
>>>>
>>>>> An A&P is uninformed in an area outside is area of training
>>>>> and expertise.
>>>> The examples (other than chloroform in grass) were well
>> ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^
>>
>> Dip**** focuses on chloroform:
>>
>>> You really are a ninny aren't you? Learning about chloroform as
>>> it pertains to aircraft
>
> Names for layers of the atmosphere is not something that one would
> need to learn as an A&P, nor is it important to know what happens to
> a gas as it is compressed.

LOL!
The FAA decides what material *will* be taught in approved A&P schools.
Nobody cares what part of it you think is unimportant.

> None of your examples were of a person making basic mistakes *within*
> his area of expertise.

The examples (other than CHLOROFORM in grass) were all within the
^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^
^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^
^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^
instructors area of expertise.

[Ed]

On Thu, 10 Dec 2009 12:00:14 -0800, Beryl > wrote:

>Alan Baker wrote:
>> In article >, Beryl
>> > wrote:
>>
>>> Alan Baker wrote:
>>>> In article >,
>>>> Beryl > wrote:
>>>>
>>>>> Alan Baker wrote:
>>>>>
>>>>>> An A&P is uninformed in an area outside is area of training
>>>>>> and expertise.
>>>>> The examples (other than chloroform in grass) were well
>>> ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^
>>>
>>> Dip**** focuses on chloroform:
>>>
>>>> You really are a ninny aren't you? Learning about chloroform as
>>>> it pertains to aircraft
>>
>> Names for layers of the atmosphere is not something that one would
>> need to learn as an A&P, nor is it important to know what happens to
>> a gas as it is compressed.
>
>LOL!
>The FAA decides what material *will* be taught in approved A&P schools.
>Nobody cares what part of it you think is unimportant.
>
>> None of your examples were of a person making basic mistakes *within*
>> his area of expertise.
>
>The examples (other than CHLOROFORM in grass) were all within the
> ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^
> ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^
> ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^
>instructors area of expertise.
Uh, guys, isn't the stuff in grass Chlorophyll?

[Steve Hix[_2_]]

In article >,
Ed > wrote:

> On Thu, 10 Dec 2009 12:00:14 -0800, Beryl > wrote:
>
> >Alan Baker wrote:
> >> In article >, Beryl
> >> > wrote:
> >>
> >>> Alan Baker wrote:
> >>>> In article >,
> >>>> Beryl > wrote:
> >>>>
> >>>>> Alan Baker wrote:
> >>>>>
> >>>>>> An A&P is uninformed in an area outside is area of training
> >>>>>> and expertise.
> >>>>> The examples (other than chloroform in grass) were well
> >>> ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^
> >>>
> >>> Dip**** focuses on chloroform:
> >>>
> >>>> You really are a ninny aren't you? Learning about chloroform as
> >>>> it pertains to aircraft
> >>
> >> Names for layers of the atmosphere is not something that one would
> >> need to learn as an A&P, nor is it important to know what happens to
> >> a gas as it is compressed.
> >
> >LOL!
> >The FAA decides what material *will* be taught in approved A&P schools.
> >Nobody cares what part of it you think is unimportant.
> >
> >> None of your examples were of a person making basic mistakes *within*
> >> his area of expertise.
> >
> >The examples (other than CHLOROFORM in grass) were all within the
> > ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^
> > ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^
> > ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^
> >instructors area of expertise.
> Uh, guys, isn't the stuff in grass Chlorophyll?

Usually, unless one of the lab assistants found the key to the stockroom.

[Beryl[_3_]]

Ed wrote:
> On Thu, 10 Dec 2009 12:00:14 -0800, Beryl > wrote:
>
>> Alan Baker wrote:
>>> In article >, Beryl
>>> > wrote:
>>>
>>>> Alan Baker wrote:
>>>>> In article >,
>>>>> Beryl > wrote:
>>>>>
>>>>>> Alan Baker wrote:
>>>>>>
>>>>>>> An A&P is uninformed in an area outside is area of training
>>>>>>> and expertise.
>>>>>> The examples (other than chloroform in grass) were well
>>>> ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^
>>>>
>>>> Dip**** focuses on chloroform:
>>>>
>>>>> You really are a ninny aren't you? Learning about chloroform as
>>>>> it pertains to aircraft
>>> Names for layers of the atmosphere is not something that one would
>>> need to learn as an A&P, nor is it important to know what happens to
>>> a gas as it is compressed.
>> LOL!
>> The FAA decides what material *will* be taught in approved A&P schools.
>> Nobody cares what part of it you think is unimportant.
>>
>>> None of your examples were of a person making basic mistakes *within*
>>> his area of expertise.
>> The examples (other than CHLOROFORM in grass) were all within the
>> ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^
>> ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^
>> ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^
>> instructors area of expertise.
> Uh, guys, isn't the stuff in grass Chlorophyll?

Ordinarily, but instructor took care of mom's lawn. Final minutes of
break time, waiting for class to resume, instructor was chatting with
adoring student about mom's lawn being greenest in the neighborhood.
Said student became agitated at me when I told him instructor was wrong
about tremendous G forces due to high speed. Student later spit on hood
of my truck in parking lot.

[Alan Baker]

In article >,
Beryl > wrote:

> Ed wrote:
> > On Thu, 10 Dec 2009 12:00:14 -0800, Beryl > wrote:
> >
> >> Alan Baker wrote:
> >>> In article >, Beryl
> >>> > wrote:
> >>>
> >>>> Alan Baker wrote:
> >>>>> In article >,
> >>>>> Beryl > wrote:
> >>>>>
> >>>>>> Alan Baker wrote:
> >>>>>>
> >>>>>>> An A&P is uninformed in an area outside is area of training
> >>>>>>> and expertise.
> >>>>>> The examples (other than chloroform in grass) were well
> >>>> ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^
> >>>>
> >>>> Dip**** focuses on chloroform:
> >>>>
> >>>>> You really are a ninny aren't you? Learning about chloroform as
> >>>>> it pertains to aircraft
> >>> Names for layers of the atmosphere is not something that one would
> >>> need to learn as an A&P, nor is it important to know what happens to
> >>> a gas as it is compressed.
> >> LOL!
> >> The FAA decides what material *will* be taught in approved A&P schools.
> >> Nobody cares what part of it you think is unimportant.
> >>
> >>> None of your examples were of a person making basic mistakes *within*
> >>> his area of expertise.
> >> The examples (other than CHLOROFORM in grass) were all within the
> >> ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^
> >> ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^
> >> ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^
> >> instructors area of expertise.
> > Uh, guys, isn't the stuff in grass Chlorophyll?
>
> Ordinarily, but instructor took care of mom's lawn. Final minutes of
> break time, waiting for class to resume, instructor was chatting with
> adoring student about mom's lawn being greenest in the neighborhood.
> Said student became agitated at me when I told him instructor was wrong
> about tremendous G forces due to high speed. Student later spit on hood
> of my truck in parking lot.

As I said, an instructor being wrong about things outside of his area of
expertise and training proves nothing.

--
Alan Baker
Vancouver, British Columbia
<http://gallery.me.com/alangbaker/100008/DSCF0162/web.jpg>

[Beryl[_3_]]

Alan Baker wrote:

> As I said,

"nor is it important to know what happens to a gas as
it is compressed."

[Alan Baker]

In article >,
Beryl > wrote:

> Alan Baker wrote:
>
> > As I said,
>
> "nor is it important to know what happens to a gas as
> it is compressed."

Yup. It is not important to an A&P instructor to know whether a gas gets
hotter or colder when compressed.

But excellent job of snip mangling!

--
Alan Baker
Vancouver, British Columbia
<http://gallery.me.com/alangbaker/100008/DSCF0162/web.jpg>

[Beryl[_3_]]

Alan Baker wrote:
> In article >,
> Beryl > wrote:
>
>> Alan Baker wrote:
>>
>>> As I said,
>> "nor is it important to know what happens to a gas as
>> it is compressed."
>
> Yup. It is not important to an A&P instructor to know whether a gas gets
> hotter or colder when compressed.

That's part of the entry level physics stuff, comes up in the first
class. It's in the "General" textbook. And 16 months later, it could
appear on your written or oral test. So it's sort of important for the
A&P instructor to know.

[Alan Baker]

In article >,
Beryl > wrote:

> Alan Baker wrote:
> > In article >,
> > Beryl > wrote:
> >
> >> Alan Baker wrote:
> >>
> >>> As I said,
> >> "nor is it important to know what happens to a gas as
> >> it is compressed."
> >
> > Yup. It is not important to an A&P instructor to know whether a gas gets
> > hotter or colder when compressed.
>
> That's part of the entry level physics stuff, comes up in the first
> class. It's in the "General" textbook. And 16 months later, it could
> appear on your written or oral test. So it's sort of important for the
> A&P instructor to know.

Is it? Care to actually support that statement?

--
Alan Baker
Vancouver, British Columbia
<http://gallery.me.com/alangbaker/100008/DSCF0162/web.jpg>

[Jim Logajan]

Ed > wrote:
> Guys, doesn't this entire thread sort of smack of wrestling with pigs?

I'm afraid I wouldn't know, having no basis for comparison.... ;-)

[Barnyard BOb]

"Morgans" wrote:

>
>I think his view of individual points of observations are splitting
>toadstools.



>
>But that is my opinion, and like everyone, we all have but-holes....

=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=

Too much information, Morgans. :-)

P.S.
YOU may indeed have a "but-hole, BUT....
expect the major to anatomically have
"buttholes, butt-holes or butt holes".

MERRY CHRISTMAS all.


Barnyard BOb - gone flying

[Morgans[_2_]]

"Barnyard BOb" > wrote >
> =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=
>
> Too much information, Morgans. :-)
>
> P.S.
> YOU may indeed have a "but-hole, BUT....
> expect the major to anatomically have
> "buttholes, butt-holes or butt holes".
>
> MERRY CHRISTMAS all.

So nice of you to stop it, butt is that all you have to contribute to
increase our collective wisdom? (I left an extra "t" back there for you to
use when you need one )

Speaking of butt-holes, where is one when you need one? <g>

Merry Christmas to you, and yours!
--
Jim in NC

P.S. Nice to be back like the old days, for a moment or two. ;-)