A dumb doubt on stalls

[[email protected]]

Is it possible for an aircraft to stall and sink nose-up tail-down
instead of pitching nose-down? Or does aircraft design inherently
preclude that? :)

Thanks in advance,

Ramapriya

[Dylan Smith]

On 2006-06-20, > wrote:
> Is it possible for an aircraft to stall and sink nose-up tail-down
> instead of pitching nose-down? Or does aircraft design inherently
> preclude that? :)

Conventional light planes should not do that (i.e. certified, non-canard
designs). However, some rear engined T-tailed airliner designs WILL do
that. It is called a deep stall, and is irrecoverable.

http://en.wikipedia.org/wiki/Deep_stall

has a diagram. Note that in a rear engined T tailed plane, the wash from
the wing will prevent appreciable thrust being made by the engines, so
you can't just 'power' out of it either.

--
Yes, the Reply-To email address is valid.
Oolite-Linux: an Elite tribute: http://oolite-linux.berlios.de

[Ron Rosenfeld]

On 20 Jun 2006 03:30:46 -0700, wrote:

>Is it possible for an aircraft to stall and sink nose-up tail-down
>instead of pitching nose-down? Or does aircraft design inherently
>preclude that? :)
>
>Thanks in advance,
>
>Ramapriya

Thinking about it simply, if the airplane is not generating lift, it should
fall with the heaviest end down. For most light GA a/c, the engine is up
front, so that end goes down first.


Ron (EPM) (N5843Q, Mooney M20E) (CP, ASEL, ASES, IA)

[Bob Moore]

Dylan Smith wrote

> On 2006-06-20, > wrote:
>> Is it possible for an aircraft to stall and sink nose-up tail-down
>> instead of pitching nose-down? Or does aircraft design inherently
>> preclude that? :)

YES

> Conventional light planes should not do that (i.e. certified, non-canard
> designs). However, some rear engined T-tailed airliner designs WILL do
> that. It is called a deep stall, and is irrecoverable.>
> http://en.wikipedia.org/wiki/Deep_stall

This Wikipedia article leaves a lot to be desired. Stick Shakers are not
related to the deep stall. Stall Warning devices which include stick
shakers are required because of a lack of sufficient natural stall warning
buffet in any airplane. The cure for the Deep Stall was the "Stick Pusher"
which prevented the aircraft from reaching the stalling AOA in the first
place.

> has a diagram. Note that in a rear engined T tailed plane, the wash from
> the wing will prevent appreciable thrust being made by the engines, so
> you can't just 'power' out of it either.

Wing wash had nothing to do with engine power available, the extreamly high
AOA for the deep stall also put the engine cowls at an extream angle from
the relative wind resulting in compressor stalls.

Bob Moore

[[email protected]]

Dylan Smith wrote:
> Conventional light planes should not do that (i.e. certified, non-canard
> designs).

A Morane Saulnier Rallye is a conventional certified light plane and it
just drops with its nose up and tail down when stalled.
But I suppose it is an exception to the rule.

-Kees.

[[email protected]]

Ron Rosenfeld wrote:
> Thinking about it simply, if the airplane is not generating lift, it should
> fall with the heaviest end down. For most light GA a/c, the engine is up
> front, so that end goes down first.


The wing's center of pressure moves forward as the stall is
approached, as the laminar flow over the top of the wing breaks up
toward the trailing edge and lift is lost over the aft area of the
wing. At the stall, the center of pressure moves aft as the whole
laminar flow goes turbulent, and the CP shift lifts the tail.
The loss of effective downforce on the stabilizer as speed
decreases contributes to the nose drop. That's the "heavy end down"
effect you speak of.

Dan

[Jose]

> This Wikipedia article leaves a lot to be desired.

Why not edit it? That's how a wiki works. :)

Jose
--
The monkey turns the crank and thinks he's making the music.
for Email, make the obvious change in the address.

[Jim Macklin]

The location of the center of gravity directly relates to an
aircraft's dynamic and static stability. Stall behavior
with a CG aft of the center of pressure on a wing will cause
the stalled aircraft to pitch deeper into the stall. The
stall buffet comes from disturbance of the air flow over the
wing root, but the actual stall comes from the tail.


--
James H. Macklin
ATP,CFI,A&P

--
The people think the Constitution protects their rights;
But government sees it as an obstacle to be overcome.
some support
http://www.usdoj.gov/olc/secondamendment2.htm
See http://www.fija.org/ more about your rights and duties.


> wrote in message
oups.com...
| Is it possible for an aircraft to stall and sink nose-up
tail-down
| instead of pitching nose-down? Or does aircraft design
inherently
| preclude that? :)
|
| Thanks in advance,
|
| Ramapriya
|

[Larry Dighera]

On Tue, 20 Jun 2006 07:36:13 -0400, Ron Rosenfeld
> wrote in
>::

>On 20 Jun 2006 03:30:46 -0700, wrote:
>
>>Is it possible for an aircraft to stall and sink nose-up tail-down
>>instead of pitching nose-down? Or does aircraft design inherently
>>preclude that? :)
>>
>>Thanks in advance,
>>
>>Ramapriya
>
>Thinking about it simply, if the airplane is not generating lift, it should
>fall with the heaviest end down. For most light GA a/c, the engine is up
>front, so that end goes down first.

You may recall, that Galileo Galilei (1564-1642) performed experiments
to verify that heavier bodies do not fall faster than lighter ones,
rather that they fall at the same rate, therefore your analysis is
incorrect.

While it is true, that an airplane in a vacuum will fall in any
orientation, in the atmosphere, it is practically impossible to
prevent the falling airplane's wings from providing some lift. Given
an airplane correctly loaded within its weight and balance envelope,
when the wing is generating lift, the center of lift is located behind
the aircraft's center of gravity. The center of gravity acts as a
fulcrum, and the lifting force aft of the CG is acting in the
direction roughly upward, while the gradational force acts uniformly
on the entire airplane in a downward direction resulting in the nose
dropping as the aircraft was designed.

[Kingfish]

Bob Moore wrote:

>>> Stick Shakers are not related to the deep stall. Stall Warning devices which include stick shakers are required because of a lack of sufficient natural stall warning
> buffet in any airplane. The cure for the Deep Stall was the "Stick Pusher"
> which prevented the aircraft from reaching the stalling AOA in the first place<<<

I just started flying p/t as SIC in a Pilatus PC12. Never had any
exposure to a stick shaker or pusher, but the PC12 has both. Stall
training in that plane was *interesting* although I did't realize those
systems were driven by the AOA sensor and not airspeed.

[B A R R Y]

Kingfish wrote:
>
> I just started flying p/t as SIC in a Pilatus PC12.

Neat plane!

I saw one a few weeks back @ MMK. I was amazed at the landing and
takeoff performance.

[B A R R Y]

Kingfish wrote:
> We're based at OXC (Oxford CT)
>


Going to the Rinker Buck thing tonight?

[[email protected]]

Jim Macklin wrote:
> The stall buffet comes from disturbance of the air flow over the wing root, but the
> actual stall comes from the tail.


Actual stall comes from the tail?? Meaning?? This is more arcane than
I'd bargained for :(

Ramapriya

[Roy Smith]

Kingfish > wrote:
> I just started flying p/t as SIC in a Pilatus PC12. Never had any
> exposure to a stick shaker or pusher, but the PC12 has both. Stall
> training in that plane was *interesting* although I did't realize those
> systems were driven by the AOA sensor and not airspeed.

I've never flown anything with a real AOA sensor, but it seems obvious
that on any aircraft equipped with one, anything having anything to do
with stall detection would be driven by it. What else would be the
point of having the sensor in the first place?

[Kingfish]

B A R R Y wrote:
> Kingfish wrote:
> > We're based at OXC (Oxford CT)
> >

> Going to the Rinker Buck thing tonight?

Don't know anything about it. I'll be there for training though. Is he
making an appearance?

[B A R R Y]

Kingfish wrote:
> B A R R Y wrote:
>> Kingfish wrote:
>>> We're based at OXC (Oxford CT)
>>>
>
>> Going to the Rinker Buck thing tonight?
>
> Don't know anything about it. I'll be there for training though. Is he
> making an appearance?
>

Check your hotmail.

[Marty Shapiro]

wrote in
oups.com:

>
> Dylan Smith wrote:
>> Conventional light planes should not do that (i.e. certified, non-canard
>> designs).
>
> A Morane Saulnier Rallye is a conventional certified light plane and it
> just drops with its nose up and tail down when stalled.
> But I suppose it is an exception to the rule.
>
> -Kees.
>
>

In the Rallye 235E, power off, as you reach full back on the yoke, you will
encounter mild buffet and descend in a level flight attitude at slightly
over 1,000 fpm with an IAS of about 40 MPH. Aerilons are still effective
and you can easily turn in this configuration without using your rudder.
(You will get a very nice adverse yaw demonstration doing this). Just relax
slightly from full back on the yoke and the nose drops immediately. For
more fun, keep the yoke back and slowly add power and watch your VSI jump
past +500 fpm while you are still encountering mild buffet.

--
Marty Shapiro
Silicon Rallye Inc.

(remove SPAMNOT to email me)

[Orval Fairbairn]

In article . com>,
wrote:

> Is it possible for an aircraft to stall and sink nose-up tail-down
> instead of pitching nose-down? Or does aircraft design inherently
> preclude that? :)
>
> Thanks in advance,
>
> Ramapriya

The short answer is, "yes, it is possible, under unusual conditions."

Airplane certification requires nose-down pitch upon stall; however,
stalling with aft CG (usually well beyond the approved envelope) or deep
stall may result in an unrecoverable, nose-high sink.

Some examples:

Twin Comanche in deep stall

Beech Baron in deep stall

Velocity in deep stall.

The baron and TC have nacelles that have flat undersides that cause
major pitch-up moment in a deep stall.

The Velocity has a very large forward underside that does the same
thing. In fact, the designer rode one all the way into a swamp doing
deep stall tests. He was about to bail out when he noticed that the sink
rate was on the order of 1000 fpm, so he rode it down and emerged unhurt.
In fact, the airplane was repaired and flew again.

I heard of a pair of engineers from SRI who took a TC up high and tried
the deep stall. They tried everything to recover and ended up unbuckling
their seatbelts and getting under the panel. The plane finally recovered
into a high speed dive and bent the structure on recovery.

[Bob Moore]

> Jim Macklin wrote:
>> The stall buffet comes from disturbance of the air flow over the wing
>> root, but the actual stall comes from the tail.

> Ramapriya wrote:
> Actual stall comes from the tail?? Meaning?? This is more arcane than
> I'd bargained for :(

I think that Jim got it bassackwards. Approaching the stall, airflow at
the wing root separates and strikes the horizontal stabilizer, shaking
it and providing the stall warning required by FAR 23.207.

From Wikipedia:
In aerodynamics, a stall occurs when the critical angle of attack is
exceeded, causing loss of lift and a large increase in drag due to
disruption of airflow.


> Section 23.207: Stall warning.
> (a) There must be a clear and distinctive stall warning, with the
flaps and landing gear in any normal position, in straight and turning
flight.
>
> (b) The stall warning may be furnished either through the inherent
aerodynamic qualities of the airplane or by a device that will give
clearly distinguishable indications under expected conditions of flight.
However, a visual stall warning device that requires the attention of
the crew within the cockpit is not acceptable by itself.
>
> (c) During the stall tests required by §23.201(b) and §23.203(a)(1),
the stall warning must begin at a speed exceeding the stalling speed by
a margin of not less than 5 knots and must continue until the stall
occurs.

> (e) During the stall tests required by §23.203(a)(2), the stall
warning must begin sufficiently in advance of the stall for the stall to
be averted by pilot action taken after the stall warning first occurs.

Bob Moore

[Kingfish]

Roy Smith wrote:
> I've never flown anything with a real AOA sensor, but it seems obvious
> that on any aircraft equipped with one, anything having anything to do
> with stall detection would be driven by it. What else would be the
> point of having the sensor in the first place?

Obvious to you, maybe. The Pilatypus was a big step up from a Lance for
me, with exposure to systems I've never flown with before.

[Kingfish]

Orval Fairbairn wrote:
> The Velocity has a very large forward underside that does the same
> thing. In fact, the designer rode one all the way into a swamp doing
> deep stall tests. He was about to bail out when he noticed that the sink
> rate was on the order of 1000 fpm, so he rode it down and emerged unhurt.
> In fact, the airplane was repaired and flew again.

Interesting. I can just imagine the thought process in that scenario.
"Oh s**t I've lost it! Oh God!... uh... hey, it's only falling at
1000fpm - this should be survivable!! I'll stay with it then!! <G>


> I heard of a pair of engineers from SRI who took a TC up high and tried
> the deep stall. They tried everything to recover and ended up unbuckling
> their seatbelts and getting under the panel. The plane finally recovered
> into a high speed dive and bent the structure on recovery.

I would like to see two humans fit under the panel in a Twinkie. Were
these guys circus freaks??

[Jim Macklin]

The tail is more heavily loaded and at a higher angle of
attack than the wing. The tail lift is actually a tail down
force. You can look up a textbook on stability, control and
weight and balance to see that with a conventional tail, the
wing lift is located on the center of pressure, while the CG
is located some small distance forward of that point. The
tail provides a downward forced on the tail that creates a
moment around the CG to balance the moment arm between the
center of pressure and the CG.

When the pilot feels a stall buffet, it is caused by air
flow separation that impacts the tail or some other part of
the structure. But the stall break happens when the tail
stalls and the CG moment is no longer countered by the tail
down force.

On a canard aircraft such as Burt Rutan designs, the forward
wing is heavily loaded and lifts up and the main wing is
more lightly loaded and at a lower angle of attack. When
the plane approaches the stall, the forward wing stalls
first and the nose drops.
see http://www.faa.gov/pilots/training/handbook/
this is the link to the chapters you
need
http://www.faa.gov/library/manuals/aviation/pilot_handbook/media/faa-h-8083-25-1of4.pdf


--
James H. Macklin
ATP,CFI,A&P

> wrote in message
oups.com...
| Jim Macklin wrote:
| > The stall buffet comes from disturbance of the air flow
over the wing root, but the
| > actual stall comes from the tail.
|
|
| Actual stall comes from the tail?? Meaning?? This is more
arcane than
| I'd bargained for :(
|
| Ramapriya
|

[Jim Macklin]

No, I said the buffet comes from the wing root, but the
actual stall is when the tail stalls and looses lift (down
force) and then the nose pitches down because the still
flying wing CP is behind the CG.

http://www.faa.gov/library/manuals/aviation/pilot_handbook/media/faa-h-8083-25-1of4.pdf



--
James H. Macklin
ATP,CFI,A&P

"Bob Moore" > wrote in message
. 122...
|> Jim Macklin wrote:
| >> The stall buffet comes from disturbance of the air flow
over the wing
| >> root, but the actual stall comes from the tail.
|
| > Ramapriya wrote:
| > Actual stall comes from the tail?? Meaning?? This is
more arcane than
| > I'd bargained for :(
|
| I think that Jim got it bassackwards. Approaching the
stall, airflow at
| the wing root separates and strikes the horizontal
stabilizer, shaking
| it and providing the stall warning required by FAR 23.207.
|
| From Wikipedia:
| In aerodynamics, a stall occurs when the critical angle of
attack is
| exceeded, causing loss of lift and a large increase in
drag due to
| disruption of airflow.
|
|
| > Section 23.207: Stall warning.
| > (a) There must be a clear and distinctive stall warning,
with the
| flaps and landing gear in any normal position, in straight
and turning
| flight.
| >
| > (b) The stall warning may be furnished either through
the inherent
| aerodynamic qualities of the airplane or by a device that
will give
| clearly distinguishable indications under expected
conditions of flight.
| However, a visual stall warning device that requires the
attention of
| the crew within the cockpit is not acceptable by itself.
| >
| > (c) During the stall tests required by §23.201(b) and
§23.203(a)(1),
| the stall warning must begin at a speed exceeding the
stalling speed by
| a margin of not less than 5 knots and must continue until
the stall
| occurs.
|
| > (e) During the stall tests required by §23.203(a)(2),
the stall
| warning must begin sufficiently in advance of the stall
for the stall to
| be averted by pilot action taken after the stall warning
first occurs.
|
| Bob Moore

[Gary Drescher]

"Jim Macklin" > wrote in message
news:J4Wlg.49291$ZW3.49195@dukeread04...
> No, I said the buffet comes from the wing root, but the
> actual stall is when the tail stalls and looses lift (down
> force) and then the nose pitches down because the still
> flying wing CP is behind the CG.

If that were true, then it wouldn't be possible to sustain a stall (in, say,
a C172) by maintaining back pressure on the yoke. But in fact, such a stall
can be sustained: the plane is stalled because the wings are past the
critical angle of attack; and the tail, which is *not* stalled and does
*not* lose lift, can hold that angle of attack if up-elevator pressure is
continued.

It is possible to stall the tail if the CG is too far forward. This is
especially likely during a landing flare, resulting in a sudden drop of the
nose. But that's not how a normal stall occurs.

> http://www.faa.gov/library/manuals/aviation/pilot_handbook/media/faa-h-8083-25-1of4.pdf

Are you referring to the paragraph about stalls on p. 3-21? First, the
information there is partly incorrect--there is no reason to think that the
tail's (downward) lift ceases during a normal stall, and (as I mentioned
above) the sustainability of such a stall (by continued back pressure) shows
that the tail's lift does not cease. Second, the paragraph does not state
that the tail's alleged loss of lift begins the plane's stall, but rather
that it contributes to a stall *recovery*.

--Gary

[[email protected]]

Jim Macklin wrote:
> No, I said the buffet comes from the wing root, but the
> actual stall is when the tail stalls and looses lift (down
> force) and then the nose pitches down because the still
> flying wing CP is behind the CG.


That applies to canards. Tuft-testing of conventional layouts proves
that the pitch-down comes from the wing's airflow breaking up, and when
that happens the CP moves well aft of the CG and pitches the nose down.
Stalling stabilizers/elevators are dangerous and are not
designed into the conventional airplane. The early Cardinal had that
problem, and would drop the nosewheel hard on the runway during the
flare, sometimes breaking it. Cessna had to put slots in the stabilator
to keep it from stalling. Ice on the stab can also cause stabilizer
stall and control reversal (pull back, nose goes down). Not desireable
at all.
The aircraft service manual will have control surface travels,
as do the Type Certificate Data Sheets. Those travels are intended, in
part, to prevent stalling and control reversal.

Dan

[Gary Drescher]

"T o d d P a t t i s t" > wrote in message
...
> "Gary Drescher" > wrote:
>
>>"Jim Macklin" the
>>> actual stall is when the tail stalls and looses lift (down
>>> force) and then the nose pitches down because the still
>>> flying wing CP is behind the CG.
>>
>>If that were true, then it wouldn't be possible to sustain a stall (in,
>>say,
>>a C172) by maintaining back pressure on the yoke.
>
> It depends on what you mean by "sustain a stall." I agree
> with you that Jim's explanation of a normal stall is wrong,
> but it *is* possible (but bad) to design an aircraft such
> that the tail stalls before the wing.

Agreed. My point is just that a typical GA plane (such as the 172 I
mentioned) doesn't stall that way, contrary to Jim's claim. And one
consequence of interest to pilots is that you can remain stalled if you keep
pulling back on the yoke (instead of pushing forward as you're supposed to
when you want to recover from a stall).

--Gary

[karl gruber]

No. The wing stalls first, usually.

There have been tail stalls due to ice formtion.

karl
ATP CFI ETC


"Jim Macklin" > wrote in message
news:I0Wlg.49289$ZW3.19338@dukeread04...
> The tail is more heavily loaded and at a higher angle of
> attack than the wing. The tail lift is actually a tail down
> force. You can look up a textbook on stability, control and
> weight and balance to see that with a conventional tail, the
> wing lift is located on the center of pressure, while the CG
> is located some small distance forward of that point. The
> tail provides a downward forced on the tail that creates a
> moment around the CG to balance the moment arm between the
> center of pressure and the CG.
>
> When the pilot feels a stall buffet, it is caused by air
> flow separation that impacts the tail or some other part of
> the structure. But the stall break happens when the tail
> stalls and the CG moment is no longer countered by the tail
> down force.
>
> On a canard aircraft such as Burt Rutan designs, the forward
> wing is heavily loaded and lifts up and the main wing is
> more lightly loaded and at a lower angle of attack. When
> the plane approaches the stall, the forward wing stalls
> first and the nose drops.
> see http://www.faa.gov/pilots/training/handbook/
> this is the link to the chapters you
> need
> http://www.faa.gov/library/manuals/aviation/pilot_handbook/media/faa-h-8083-25-1of4.pdf
>
>
> --
> James H. Macklin
> ATP,CFI,A&P
>
> > wrote in message
> oups.com...
> | Jim Macklin wrote:
> | > The stall buffet comes from disturbance of the air flow
> over the wing root, but the
> | > actual stall comes from the tail.
> |
> |
> | Actual stall comes from the tail?? Meaning?? This is more
> arcane than
> | I'd bargained for :(
> |
> | Ramapriya
> |
>
>

[Skywise]

Bob Moore > wrote in
. 122:

> Dylan Smith wrote
<Snipola>

>> http://en.wikipedia.org/wiki/Deep_stall
>
> This Wikipedia article leaves a lot to be desired.
<Snipola>

The beauty of Wikipedia is that YOU can change it.

Brian
--
http://www.skywise711.com - Lasers, Seismology, Astronomy, Skepticism
Seismic FAQ: http://www.skywise711.com/SeismicFAQ/SeismicFAQ.html
Quake "predictions": http://www.skywise711.com/quakes/EQDB/index.html
Sed quis custodiet ipsos Custodes?

[Matt Whiting]

Jim Macklin wrote:

> The tail is more heavily loaded and at a higher angle of
> attack than the wing. The tail lift is actually a tail down
> force. You can look up a textbook on stability, control and
> weight and balance to see that with a conventional tail, the
> wing lift is located on the center of pressure, while the CG
> is located some small distance forward of that point. The
> tail provides a downward forced on the tail that creates a
> moment around the CG to balance the moment arm between the
> center of pressure and the CG.
>
> When the pilot feels a stall buffet, it is caused by air
> flow separation that impacts the tail or some other part of
> the structure. But the stall break happens when the tail
> stalls and the CG moment is no longer countered by the tail
> down force.
>
> On a canard aircraft such as Burt Rutan designs, the forward
> wing is heavily loaded and lifts up and the main wing is
> more lightly loaded and at a lower angle of attack. When
> the plane approaches the stall, the forward wing stalls
> first and the nose drops.
> see http://www.faa.gov/pilots/training/handbook/
> this is the link to the chapters you
> need
> http://www.faa.gov/library/manuals/aviation/pilot_handbook/media/faa-h-8083-25-1of4.pdf
>
>

I did a quick search and find nothing about the tail stalling before the
wing under normal conditions. On which page did you see this?

Personally, I don't believe this. If this were the case, then during a
full stall landing, the airplane would rise upward when the tail stalled
as the net force in the vertical direction would be greater upward than
downward. Yes the airplane would rotate about the center of lift and
the nose would fall, but the wing would be rising at the same time.
This isn't the way any airplane I've ever flown behaved.

Matt

[Matt Whiting]

Jim Macklin wrote:

> No, I said the buffet comes from the wing root, but the
> actual stall is when the tail stalls and looses lift (down
> force) and then the nose pitches down because the still
> flying wing CP is behind the CG.
>
> http://www.faa.gov/library/manuals/aviation/pilot_handbook/media/faa-h-8083-25-1of4.pdf

You keep referencing this 111 page document, but you don't reference
where in it you found what you mention above. What page?


Matt

[Matt Whiting]

Skywise wrote:

> Bob Moore > wrote in
> . 122:
>
>
>>Dylan Smith wrote
>
> <Snipola>
>
>>>http://en.wikipedia.org/wiki/Deep_stall
>>
>>This Wikipedia article leaves a lot to be desired.
>
> <Snipola>
>
> The beauty of Wikipedia is that YOU can change it.
>
> Brian

Which is why it leaves a lot to be desired.

Matt

[Gary Drescher]

"Matt Whiting" > wrote in message
...
> Jim Macklin wrote:
>> The tail is more heavily loaded and at a higher angle of attack than the
>> wing. The tail lift is actually a tail down force. You can look up a
>> textbook on stability, control and weight and balance to see that with a
>> conventional tail, the wing lift is located on the center of pressure,
>> while the CG is located some small distance forward of that point. The
>> tail provides a downward forced on the tail that creates a moment around
>> the CG to balance the moment arm between the center of pressure and the
>> CG.
>>
>> When the pilot feels a stall buffet, it is caused by air flow separation
>> that impacts the tail or some other part of the structure. But the stall
>> break happens when the tail stalls and the CG moment is no longer
>> countered by the tail down force.
>
> Personally, I don't believe this. If this were the case, then during a
> full stall landing, the airplane would rise upward when the tail stalled
> as the net force in the vertical direction would be greater upward than
> downward. Yes the airplane would rotate about the center of lift and the
> nose would fall, but the wing would be rising at the same time. This isn't
> the way any airplane I've ever flown behaved.
>
>> http://www.faa.gov/library/manuals/aviation/pilot_handbook/media/faa-h-8083-25-1of4.pdf
>
> I did a quick search and find nothing about the tail stalling before the
> wing under normal conditions. On which page did you see this?

There's a paragraph on p. 3-21 that makes part (but not most) of the
erroneous claim that Jim attributes to the publication. In particular, the
paragraph does say (in a discussion of a typical GA plane's normal stall)
that the tail loses lift (along with the wings). But it does not attribute
the plane's stall to the tail's supposed loss of lift; on the contrary, it
credits the supposed loss of lift with helping to recover from the stall.
(Additionally, the paragraph claims that the wings' lift *ceases* during a
stall, which is not the case.)

--Gary

[Matt Whiting]

Gary Drescher wrote:

> "Matt Whiting" > wrote in message
> ...
>
>>Jim Macklin wrote:
>>
>>>The tail is more heavily loaded and at a higher angle of attack than the
>>>wing. The tail lift is actually a tail down force. You can look up a
>>>textbook on stability, control and weight and balance to see that with a
>>>conventional tail, the wing lift is located on the center of pressure,
>>>while the CG is located some small distance forward of that point. The
>>>tail provides a downward forced on the tail that creates a moment around
>>>the CG to balance the moment arm between the center of pressure and the
>>>CG.
>>>
>>>When the pilot feels a stall buffet, it is caused by air flow separation
>>>that impacts the tail or some other part of the structure. But the stall
>>>break happens when the tail stalls and the CG moment is no longer
>>>countered by the tail down force.
>>
>>Personally, I don't believe this. If this were the case, then during a
>>full stall landing, the airplane would rise upward when the tail stalled
>>as the net force in the vertical direction would be greater upward than
>>downward. Yes the airplane would rotate about the center of lift and the
>>nose would fall, but the wing would be rising at the same time. This isn't
>>the way any airplane I've ever flown behaved.
>>
>>
>>>http://www.faa.gov/library/manuals/aviation/pilot_handbook/media/faa-h-8083-25-1of4.pdf
>>
>>I did a quick search and find nothing about the tail stalling before the
>>wing under normal conditions. On which page did you see this?
>
>
> There's a paragraph on p. 3-21 that makes part (but not most) of the
> erroneous claim that Jim attributes to the publication. In particular, the
> paragraph does say (in a discussion of a typical GA plane's normal stall)
> that the tail loses lift (along with the wings). But it does not attribute
> the plane's stall to the tail's supposed loss of lift; on the contrary, it
> credits the supposed loss of lift with helping to recover from the stall.
> (Additionally, the paragraph claims that the wings' lift *ceases* during a
> stall, which is not the case.)

Yes, that was a lot of missinformation in one post!

Matt

[Jim Macklin]

I did not reference or even read the FAA Handbook when I
posted my answer. If the wing stalled, the center of
pressure would not be creating a moment arm to drop the
nose, the tail must loose lift (stall) to cause the stall
break which causes the recovery from the approaching stall.

I referenced the "book" only to allow those who asked the
question to find a reference.

BTW, stall behavior changes drastically with the center of
gravity and to a lesser amount with weight.


--
James H. Macklin
ATP,CFI,A&P

"Matt Whiting" > wrote in message
...
| Jim Macklin wrote:
|
| > No, I said the buffet comes from the wing root, but the
| > actual stall is when the tail stalls and looses lift
(down
| > force) and then the nose pitches down because the still
| > flying wing CP is behind the CG.
| >
| >
http://www.faa.gov/library/manuals/aviation/pilot_handbook/media/faa-h-8083-25-1of4.pdf
|
| You keep referencing this 111 page document, but you don't
reference
| where in it you found what you mention above. What page?
|
|
| Matt

[Skywise]

Matt Whiting > wrote in news:Sf_lg.9891$lb.874408
@news1.epix.net:

> Skywise wrote:
>
>> Bob Moore > wrote in
>> . 122:
>>
>>
>>>Dylan Smith wrote
>>
>> <Snipola>
>>
>>>>http://en.wikipedia.org/wiki/Deep_stall
>>>
>>>This Wikipedia article leaves a lot to be desired.
>>
>> <Snipola>
>>
>> The beauty of Wikipedia is that YOU can change it.
>>
>> Brian
>
> Which is why it leaves a lot to be desired.
>
> Matt

I have heard more than once that a collection of average
people is smarter than a few experts. If no one corrects
the data then it will continue to be wrong. I've been
seriously thinking of getting an account so I can make
changes as I see the need. Mostly minuscule stuff, but
every bit would help. The only concern I have is time.

I find it fascinating, the human capacity to bitch about
something, yet not have the willingness to actually DO
soemthing to fix the problem. I'll admit up front I've
done that myself, and it's something I should change.

Brian
--
http://www.skywise711.com - Lasers, Seismology, Astronomy, Skepticism
Seismic FAQ: http://www.skywise711.com/SeismicFAQ/SeismicFAQ.html
Quake "predictions": http://www.skywise711.com/quakes/EQDB/index.html
Sed quis custodiet ipsos Custodes?

[[email protected]]

Hi Marty,

Rallyes are really fun, I miss mine from time to time. :-(

-Kees (D-EHNE)

[Peter Duniho]

"Skywise" > wrote in message
...
>>> The beauty of Wikipedia is that YOU can change it.
>>>
>>
>> Which is why it leaves a lot to be desired.
>
> I have heard more than once that a collection of average
> people is smarter than a few experts.

Nice saying, but I'm not willing to believe it. I've seen plenty of
evidence that a handful of experts can have very good, detailed, accurate
information even as the general population fails to have even a marginal
understanding of the same issue. This happens even in run-of-the-mill
educational situations, but is even worse when dealing with an issue that
has a political side, and thus numerous people who wish the science wasn't
correct making false statements about the science. It is *much* easier to
fool a collection of average people than a few experts.

There are probably situations in which the collective arrives at better
conclusions than a few experts, but I would be surprised if that's the usual
outcome.

That said, most articles in Wikipedia are not authored by a collection of
average people. The information within is generally being provided by a
small number of experts in each narrow field to which the article applies.

Nature did a comparison between Wikipedia and Encyclopedia Britannica, and
the two came about basically the same. Out of 50 randomly selected science
articles, each had only 4 serious errors, but both also had over a hundred
"minor" errors (with Wikipedia having slightly more than Britannica):
http://www.nature.com/news/2005/051212/full/438900a.html
http://news.bbc.co.uk/1/hi/technology/4530930.stm
http://news.com.com/2100-1038_3-5997332.html

Britannica, of course, questions the validity of the comparison:
http://news.bbc.co.uk/2/hi/technology/4840340.stm

There is every reason to trust Wikipedia as a reasonable resource, at least
as reasonable as any other single repository of information. Beyond that,
anyone who trusts only a single source of information to answer a question
deserves whatever faulty information they get. No single source of
information, not even the Encyclopedia Britannica or similar
well-established reference, can be considered reliable enough to stake any
serious debate on it.

The real problem comes when a person blindly trusts any source of
information, as if they can just throw out their own responsibility to know
and understand the basis for that source of information and the
characteristics that affect its reliability.

Pete

[Matt Whiting]

Jim Macklin wrote:

> I did not reference or even read the FAA Handbook when I
> posted my answer. If the wing stalled, the center of
> pressure would not be creating a moment arm to drop the
> nose, the tail must loose lift (stall) to cause the stall
> break which causes the recovery from the approaching stall.

What?? The weight of the airplane is what creates the rotation once the
lift from the wing is greatly reduced after the wing stalls.


> I referenced the "book" only to allow those who asked the
> question to find a reference.

To find a reference that is wrong.


> BTW, stall behavior changes drastically with the center of
> gravity and to a lesser amount with weight.

Sure does.

Matt

[Matt Whiting]

Skywise wrote:

> Matt Whiting > wrote in news:Sf_lg.9891$lb.874408
> @news1.epix.net:
>
>
>>Skywise wrote:
>>
>>
>>>Bob Moore > wrote in
. 122:
>>>
>>>
>>>
>>>>Dylan Smith wrote
>>>
>>><Snipola>
>>>
>>>>>http://en.wikipedia.org/wiki/Deep_stall
>>>>
>>>>This Wikipedia article leaves a lot to be desired.
>>>
>>><Snipola>
>>>
>>>The beauty of Wikipedia is that YOU can change it.
>>>
>>>Brian
>>
>>Which is why it leaves a lot to be desired.
>>
>>Matt
>
>
> I have heard more than once that a collection of average
> people is smarter than a few experts. If no one corrects
> the data then it will continue to be wrong. I've been
> seriously thinking of getting an account so I can make
> changes as I see the need. Mostly minuscule stuff, but
> every bit would help. The only concern I have is time.

If I was average, I'd say this also.

Matt

[Roy Smith]

Skywise > wrote:

> I've been seriously thinking of getting an account [on Wikipedia] so I
> can make changes as I see the need.

In about the same amount of time it took you to write that sentence, you
could have made your account. Just got to http://tinyurl.com/6fvtg, type
in a user name and a password, and you're done.

Wikipedia and usenet are similar in many ways. On both, there are experts
and idiots and everything in between. The difference is that on Wikipedia,
articles have a decent chance of evolving towards containing better and
more correct information. On usenet, the same crap just gets recycled.

[Gary Drescher]

"Jim Macklin" > wrote
> [...] If the wing stalled, the center of
> pressure would not be creating a moment arm to drop the
> nose, the tail must loose lift (stall) to cause the stall
> break which causes the recovery from the approaching stall.

The stall break occurs when the wings have already stalled, not when merely
approaching a stall. When the wings stall and then abruptly produce less
lift, the plane's flight path abruptly turns downward. The plane then
weathervanes into the relative wind, thus pitching downward.

It's true that the weathervaning itself can be explained in terms of a
reduction of (downward) lift from the elevator. However, contrary to your
explanation, the reduction of lift is not due to the tail stalling, but
rather just the opposite: the change in relative wind moves the tail's angle
of attack *away from* the (negative) critical angle (rather than toward it,
as would be necessary to stall). And also contrary to your explanation, it's
the stall (of the wings) that causes the tail to lose some lift
(because the relative wind changes), rather than vice versa.

> http://www.faa.gov/library/manuals/aviation/pilot_handbook/media/faa-h-8083-25-1of4.pdf
>
>> You keep referencing this 111 page document, but you don't
>> reference where in it you found what you mention above.
>
> I did not reference or even read the FAA Handbook when I
> posted my answer. [...]
> I referenced the [FAA Handbook] only to allow those who
> asked the question to find a reference.

Ok, but if you'd read the book that you referenced but didn't reference,
you'd have seen that it doesn't say what you thought it said. :)

--Gary

[Gary Drescher]

"Matt Whiting" > wrote in message
...
> Jim Macklin wrote:
>> If the wing stalled, the center of pressure would not be creating a
>> moment arm to drop the nose, the tail must loose lift (stall) to cause
>> the stall break which causes the recovery from the approaching stall.
>
> What?? The weight of the airplane is what creates the rotation once the
> lift from the wing is greatly reduced after the wing stalls.

Jim's right that if the CP is aft of the CG, then the wings' lift applies a
nose-down moment, and a reduction in that lift rotates the nose upward,
other things being equal. But other things are not equal (in particular, the
reduction of lift changes the flight path and the relative wind), so the
rest of Jim's explanation is wrong.

--Gary

[Jim Macklin]

Unless the wing is producing lift, there is no rotation to
reduce the angle of attack. If the wing was really stalled,
the airplane would fall flat, if it was spinning it would be
a flat spin, but if was fully stalled, it would be a deep
stall and would not rotate the nose down and it would stay
in the stall.

Under normal conditions, neither the wing or the tail fully
stalls. Stall strips, wing twist or air foil changes along
the span keep the wing from reaching the critical angle of
attack at one moment in time. Also the tailplane is usually
a different airfoil and more heavily loaded and is designed
to begin shedding lift [down-force] before the wing. The CG
range is set so that a certified airplane will have that
stable pattern.

The weight of the airplane does not cause the stall break
rotation, it is the lift moment. If it was not for the wing
lift, the airplane's mass as concentrated on the CG would
simply fall as a unit in the same attitude as it was in at
the moment.


If the center of pressure was located at the same location
as the CG, there would be no moment or force to cause
rotation.



--
James H. Macklin
ATP,CFI,A&P

--
The people think the Constitution protects their rights;
But government sees it as an obstacle to be overcome.
some support
http://www.usdoj.gov/olc/secondamendment2.htm
See http://www.fija.org/ more about your rights and duties.


"Matt Whiting" > wrote in message
...
| Jim Macklin wrote:
|
| > I did not reference or even read the FAA Handbook when I
| > posted my answer. If the wing stalled, the center of
| > pressure would not be creating a moment arm to drop the
| > nose, the tail must loose lift (stall) to cause the
stall
| > break which causes the recovery from the approaching
stall.
|
| What?? The weight of the airplane is what creates the
rotation once the
| lift from the wing is greatly reduced after the wing
stalls.
|
|
| > I referenced the "book" only to allow those who asked
the
| > question to find a reference.
|
| To find a reference that is wrong.
|
|
| > BTW, stall behavior changes drastically with the center
of
| > gravity and to a lesser amount with weight.
|
| Sure does.
|
| Matt

[Gary Drescher]

"Jim Macklin" > wrote in message
news:jvdmg.49354$ZW3.19866@dukeread04...
> Unless the wing is producing lift, there is no rotation to
> reduce the angle of attack. If the wing was really stalled,
> the airplane would fall flat,

A "really stalled" wing (that is, one that is past the critical angle of
attack) still produces lift. But even if it didn't, the tail could still
weathervane the plane nose-down into the relative wind.

> if it was spinning it would be
> a flat spin, but if was fully stalled, it would be a deep
> stall and would not rotate the nose down and it would stay
> in the stall.
>
> Under normal conditions, neither the wing or the tail fully
> stalls.

When you execute a normal stall in many typical GA planes, the wing can
certainly stall fully (that is, it reaches and exceeds the critical angle of
attack). That's why you lose altitude rapidly in a stall, even in a plane
that is maintaining level flight when just slightly above stall speed. The
tail, however, does not stall when you execute a normal stall.

> If the center of pressure was located at the same location
> as the CG, there would be no moment or force to cause
> rotation.

That's true if you're referring to the CP of the whole plane (not just to
the CP of the wings). But when the wings stall and the plane descends,
shifting the relative wind, the tail's (upward) lift increases, shifting the
plane's CP backward and pitching the nose downward. (See John Denker's
excellent explanation of decalage and angle-of-attack stability:
http://www.av8n.com/how/htm/aoastab.html#sec-teeter)

--Gary

[Roy Smith]

Gary Drescher > wrote:
> When you execute a normal stall in many typical GA planes, the wing can
> certainly stall fully (that is, it reaches and exceeds the critical angle of
> attack). That's why you lose altitude rapidly in a stall, even in a plane
> that is maintaining level flight when just slightly above stall speed. The
> tail, however, does not stall when you execute a normal stall.

Note also that once you start to descend, the relative wind is now
coming from below the airplane, further increasing the AOA and driving
the wing further into stall (assuming you continue to hold the same
pitch attitude).

[Skywise]

Roy Smith > wrote in news:roy-650C74.07172621062006
@reader2.panix.com:

> Skywise > wrote:
>
>> I've been seriously thinking of getting an account [on Wikipedia] so I
>> can make changes as I see the need.
>
> In about the same amount of time it took you to write that sentence, you
> could have made your account. Just got to http://tinyurl.com/6fvtg, type
> in a user name and a password, and you're done.

Making the account may not take much time, but editing articles
does take time and that time adds up, over time. As it is, I'm
having difficulty keeping up with what I do now. To put it
another way, my plate is full, and I'm concerned about piling
on another helping of potatoes.

Brian
--
http://www.skywise711.com - Lasers, Seismology, Astronomy, Skepticism
Seismic FAQ: http://www.skywise711.com/SeismicFAQ/SeismicFAQ.html
Quake "predictions": http://www.skywise711.com/quakes/EQDB/index.html
Sed quis custodiet ipsos Custodes?

[Skywise]

"Peter Duniho" > wrote in news:129hnvrn4upe5e8
@corp.supernews.com:

<Snipola>
> The real problem comes when a person blindly trusts any source of
> information, as if they can just throw out their own responsibility to know
> and understand the basis for that source of information and the
> characteristics that affect its reliability.

Absolutely. No one source is error free. I have found wikipedia to
be a good "reference" to remind me of something I already know but
jsut can't remember. When accuracy of details are important, I cross
reference multiple sources, both online and written.

Brian
--
http://www.skywise711.com - Lasers, Seismology, Astronomy, Skepticism
Seismic FAQ: http://www.skywise711.com/SeismicFAQ/SeismicFAQ.html
Quake "predictions": http://www.skywise711.com/quakes/EQDB/index.html
Sed quis custodiet ipsos Custodes?

[Gary Drescher]

"T o d d P a t t i s t" > wrote in message
...
> (Roy Smith) wrote:
>
>>Note also that once you start to descend, the relative wind is now
>>coming from below the airplane, further increasing the AOA and driving
>>the wing further into stall (assuming you continue to hold the same
>>pitch attitude).
>
> True. This reduces the wing lift even more, accelerating
> the path of the aircraft towards the ground.

Yup. In fact, it's that positive feedback that defines a stall in the first
place. Short of the critical angle of attack, you get negative feedback: if
the plane accelerates downward a bit, the increased angle of attack
increases the coefficient of lift, counteracting the acceleration. But past
the critical angle of attack, the increased angle of attack *decreases* the
coefficient of lift, which amplifies the acceleration instead of
counteracting it.

> The tail,
> however, is going from a negative AOA towards a positive AOA
> at which point it begins producing upward lift.. As the
> flight path angles down, the tail and wing are both lifting
> up, and that lift acts entirely on one side of the CG
> forcing the plane to rotate nose down.

Yup. Jim is focusing exclusively on the wings' CP being aft of the plane's
CG (typically). If that were the only factor in play, he'd be right that a
stall of the wings couldn't result in the nose-down rotation that occurs (in
typical GA planes) at the stall onset. But he persists in ignoring the
stall's effect on the relative wind and the AOA, even though that's been
explained by several people in this thread.

--Gary

[[email protected]]

Jim Macklin wrote:
> I did not reference or even read the FAA Handbook when I
> posted my answer. If the wing stalled, the center of
> pressure would not be creating a moment arm to drop the
> nose, the tail must loose lift (stall) to cause the stall
> break which causes the recovery from the approaching stall.

Two mistakes: An assumption that there is no center of
pressure if the wing stalls, and that the tail must lose lift (note the
spelling of "lose") to drop the nose.
Even a stalled wing generates lift, since there is still air
impacting its lower surface. The center of pressure moves forward
toward the CG as the wing's angle of attack increases, and with the
stall beginning to form it moves forward some more, but never ahead of
the CG. That's because the decreasing lift over the aft portion of the
wing, caused by the boundary layer breakup, leaves the forward part of
the wing to do much of the lifting. As the stall becomes complete the
center of pressure moves aft again, as the lift being generated comes
pretty much all from the lower surface, and that CP movement causes a
pitch-down force. Look at any good textbook and see it. Our Canadian
texts show it well (Aeroplane Flight Training Manual, 4th Edition, page
6). I couldn't find a good diagram on the 'net. There are plenty of
airfoil performance graphs that show CP movement with AOA.
The tail has only so much authority to raise the nose. As speed
decreases, it loses some of that authority and the pilot must either
pull back more, if he can, or watch the nose drop if he has no more
travel. It's not dropping because the tail is stalling; it just doesn't
have any more down-force to give, because it's too slow and because its
AOA is getting too negative.
In some airplanes, the elevator travel was limited to
prevent having enough authority to achieve a stall, in the hope of
avoiding the deadly stall/spin that killed so many pilots in the past.
The Ercoupe comes to mind as one of those "safe" airplanes. You could
try to hold the nose up but as speed decreased it would fall before the
wing stalled. Those airplanes killed people by getting them into rapid
sink situations instead.

Dan

[Doug]

Any treatise on aircraft stalls is going to be complicated if it gets
into detail. I just teach that the wind stops generating lift and
therefore the aircraft descends. Complicating it with (possible)
simultaneous tail stalls unecessarily confuses things. A stall is all
about angle of attack to the relative wind. When an airfoil reaches the
critical angle of attack to the relative wind, the airfoil stalls.

Now as to why the nose drops, that IS complicated. But the student
should know that a forward center of gravity is a good thing to have in
stall recovery. It is rear cg that invites the plane to be difficult to
recover from a stall.

Also, a stall is not necessarily followed by a nose drop. Take for
instance an aerobatic plane recovering from a steep dive with excessive
pull back on the stick. It stalls, but does not have a nose drop. The
plane just mushes down in a stall (or near stall). It is not nose high
to the horizon either.

[Matt Whiting]

Roy Smith wrote:

> Skywise > wrote:
>
>
>>I've been seriously thinking of getting an account [on Wikipedia] so I
>>can make changes as I see the need.
>
>
> In about the same amount of time it took you to write that sentence, you
> could have made your account. Just got to http://tinyurl.com/6fvtg, type
> in a user name and a password, and you're done.
>
> Wikipedia and usenet are similar in many ways. On both, there are experts
> and idiots and everything in between. The difference is that on Wikipedia,
> articles have a decent chance of evolving towards containing better and
> more correct information. On usenet, the same crap just gets recycled.

What causes it to evolve towards more accuracy? I haven't used it, but
I thought most anyone could add to or change the definitions contained
therein. Is this not how it works? Is there some sort of review and
approval process?


Matt

[Matt Whiting]

Jim Macklin wrote:

> Unless the wing is producing lift, there is no rotation to
> reduce the angle of attack. If the wing was really stalled,
> the airplane would fall flat, if it was spinning it would be
> a flat spin, but if was fully stalled, it would be a deep
> stall and would not rotate the nose down and it would stay
> in the stall.

The lift from the wing doesn't go to zero during a stall.


> Under normal conditions, neither the wing or the tail fully
> stalls. Stall strips, wing twist or air foil changes along
> the span keep the wing from reaching the critical angle of
> attack at one moment in time. Also the tailplane is usually
> a different airfoil and more heavily loaded and is designed
> to begin shedding lift [down-force] before the wing. The CG
> range is set so that a certified airplane will have that
> stable pattern.

I'm now really curious to hear your definition of what stall means.


> The weight of the airplane does not cause the stall break
> rotation, it is the lift moment. If it was not for the wing
> lift, the airplane's mass as concentrated on the CG would
> simply fall as a unit in the same attitude as it was in at
> the moment.

No it won't because there is still some lift from the wing, however, it
is now less than the weight of the airplane so the imbalance in forces
causes the airplane to both descend and rotate. It would only fall
downward in a flat attitude of the lift (and drag) of the wing and tail
and fuselage went either completely to zero or remained perfectly equal
forward and rearward of the CG.



> If the center of pressure was located at the same location
> as the CG, there would be no moment or force to cause
> rotation.

Sure, there is still the force from the tail.

Are you really a CFI and ATP as your .sig advertises?

Matt

[Matt Whiting]

T o d d P a t t i s t wrote:

> "Jim Macklin" > wrote:
>
>
>>Unless the wing is producing lift, there is no rotation to
>>reduce the angle of attack.
>
>
> If you simply drop an aircraft flat, it will rotate nose
> down. The wing is fully stalled (AOA=90) and the CP is well
> behind the CG producing the rotation. When the main wing
> stalls, lift is reduced and the same thing happens.
>
>
>>If the wing was really stalled, the airplane would fall flat,
>
>
> Why do you think so? A stalled wing is still producing
> lift, and unless the CP and CG are aligned the plane will
> rotate. Planes are designed to rotate nose down in this
> situation.

And it still produces drag in any event. It doesn't matter if the force
applied is due to lift or drag, it will still cause a rotation about the
CG if the forces are unbalanced.


Matt

[george]

wrote:
> Hi Marty,
>
> Rallyes are really fun, I miss mine from time to time. :-(
>
Great short field performance especially the 885

[Gary Drescher]

"Matt Whiting" > wrote in message
...
> Jim Macklin wrote:
>
>> If the center of pressure was located at the same location as the CG,
>> there would be no moment or force to cause rotation.
>
> Sure, there is still the force from the tail.

No, Jim is right if he's referring here to the plane's CP (not just the
wings' CP).

--Gary

[Gary Drescher]

"Matt Whiting" > wrote in message
...
>T o d d P a t t i s t wrote:
>> A stalled wing is still producing
>> lift, and unless the CP and CG are aligned the plane will
>> rotate. Planes are designed to rotate nose down in this
>> situation.
>
> And it still produces drag in any event. It doesn't matter if the force
> applied is due to lift or drag, it will still cause a rotation about the
> CG if the forces are unbalanced.

No, not necessarily. Even if the forces are unbalanced (which just means
there's nonzero acceleration), there's still no rotation if the plane's CP
coincides with its CG (as Jim pointed out).

Moreover, at least for a high-wing plane, rotation caused by drag upon the
wing would be nose-up rotation, not nose-down, and thus would not account
for the nose-down pitch at the stall onset, which is what's under
discussion.

--Gary

[Matt Whiting]

Gary Drescher wrote:
> "Matt Whiting" > wrote in message
> ...
>
>>Jim Macklin wrote:
>>
>>
>>>If the center of pressure was located at the same location as the CG,
>>>there would be no moment or force to cause rotation.
>>
>>Sure, there is still the force from the tail.
>
>
> No, Jim is right if he's referring here to the plane's CP (not just the
> wings' CP).

True, and the odds of that happening are infinitesimal.

Matt

[Gary Drescher]

"Matt Whiting" > wrote in message
...
> Gary Drescher wrote:
>> "Matt Whiting" > wrote in message
>> ...
>>
>>>Jim Macklin wrote:
>>>>If the center of pressure was located at the same location as the CG,
>>>>there would be no moment or force to cause rotation.
>>>
>>>Sure, there is still the force from the tail.
>>
>> No, Jim is right if he's referring here to the plane's CP (not just the
>> wings' CP).
>
> True, and the odds of that happening are infinitesimal.

You're referring to the odds of the plane's CP and CG coinciding? There's
nothing unlikely about that--it's what happens whenever the plane is *not*
changing pitch.

--Gary

[Matt Whiting]

Gary Drescher wrote:
> "Matt Whiting" > wrote in message
> ...
>
>>Gary Drescher wrote:
>>
>>>"Matt Whiting" > wrote in message
...
>>>
>>>
>>>>Jim Macklin wrote:
>>>>
>>>>>If the center of pressure was located at the same location as the CG,
>>>>>there would be no moment or force to cause rotation.
>>>>
>>>>Sure, there is still the force from the tail.
>>>
>>>No, Jim is right if he's referring here to the plane's CP (not just the
>>>wings' CP).
>>
>>True, and the odds of that happening are infinitesimal.
>
>
> You're referring to the odds of the plane's CP and CG coinciding? There's
> nothing unlikely about that--it's what happens whenever the plane is *not*
> changing pitch.

The topic is stalling the airplane. That isn't a steady-state situation
as is straight and level and unaccelerated flight.

Matt

[Jim Macklin]

Feel free to look me up on the FAA web. Certificated
airplanes are designed to not fully stall the wing or the
tail for that matter. But within the limits of what does
happen, and without discussing wash-in, wash-out, twist,
airfoil section changes, control stops, stick shaker and
pullers, gust loading, accelerated stalls, mushing, getting
a useable idea of what happens when the controls are applied
smoothly, violently or the airplane breaks apart in flight.

If the nose would always go down from a stall, spin chutes
would not be required. If the airplane is abused in flight,
it will do some pretty remarkable things. I know a Beech
test pilot who wondered about what would happen in an E90 at
cruise if you put the props into reverse. The airplane did
not break, but they were reported to have changed their
clothes after the flight. Same pilot tried the same thing
in an F90 with the T-tail and nothing really uncontrollable
happened.

It is possible to design a wing that will stall, 100% across
the entire span, but it won't be certified for civil use.

If the tail surface reaches max lift (down-force) and you
try to go slower, it will begin the stall as air flow
reaches the critical angle of attack on the tail
PROGRESSIVELY and the nose will drop because the moment
between the CP and CG will not be countered by the tail
forces. Do it slowly and the nose pitches down slowly.
Pull a few Gs and the reaction is faster and the degree to
which the stall progresses on the tail and wing is much
faster because inertia will carry the aircraft past the
critical angles at a higher kinetic energy level.


--
James H. Macklin
ATP,CFI,A&P

"Matt Whiting" > wrote in message
...
| Jim Macklin wrote:
|
| > Unless the wing is producing lift, there is no rotation
to
| > reduce the angle of attack. If the wing was really
stalled,
| > the airplane would fall flat, if it was spinning it
would be
| > a flat spin, but if was fully stalled, it would be a
deep
| > stall and would not rotate the nose down and it would
stay
| > in the stall.
|
| The lift from the wing doesn't go to zero during a stall.
|
|
| > Under normal conditions, neither the wing or the tail
fully
| > stalls. Stall strips, wing twist or air foil changes
along
| > the span keep the wing from reaching the critical angle
of
| > attack at one moment in time. Also the tailplane is
usually
| > a different airfoil and more heavily loaded and is
designed
| > to begin shedding lift [down-force] before the wing.
The CG
| > range is set so that a certified airplane will have that
| > stable pattern.
|
| I'm now really curious to hear your definition of what
stall means.
|
|
| > The weight of the airplane does not cause the stall
break
| > rotation, it is the lift moment. If it was not for the
wing
| > lift, the airplane's mass as concentrated on the CG
would
| > simply fall as a unit in the same attitude as it was in
at
| > the moment.
|
| No it won't because there is still some lift from the
wing, however, it
| is now less than the weight of the airplane so the
imbalance in forces
| causes the airplane to both descend and rotate. It would
only fall
| downward in a flat attitude of the lift (and drag) of the
wing and tail
| and fuselage went either completely to zero or remained
perfectly equal
| forward and rearward of the CG.
|
|
|
| > If the center of pressure was located at the same
location
| > as the CG, there would be no moment or force to cause
| > rotation.
|
| Sure, there is still the force from the tail.
|
| Are you really a CFI and ATP as your .sig advertises?
|
| Matt

[Jim Macklin]

Thanks. Now tell them why they use spin chutes.



"Gary Drescher" > wrote in message
. ..
| "Matt Whiting" > wrote in message
| ...
| > Jim Macklin wrote:
| >
| >> If the center of pressure was located at the same
location as the CG,
| >> there would be no moment or force to cause rotation.
| >
| > Sure, there is still the force from the tail.
|
| No, Jim is right if he's referring here to the plane's CP
(not just the
| wings' CP).
|
| --Gary
|
|

[Gary Drescher]

"Jim Macklin" > wrote in message
news:P3mmg.49385$ZW3.25845@dukeread04...
> Thanks. Now tell them why they use spin chutes.

Spin chutes are used for reasons that have nothing to do with what's in
dispute here.

> If the nose would always go down from a stall, spin chutes
> would not be required.

No one has been saying that the nose *always* goes down from a stall. What
we're all saying is that when the nose does go down (in a normally executed
stall on a typical GA plane), it's because the wing stalls, and not
(contrary to your claim) because the tail stalls.

The tail doesn't even come close to stalling; in fact, the decrease in
(downward) tail lift that helps pitch the nose down occurs because the tail
was moved *away* from its (negative) critical angle, not towards it. And
that change occurs because the plane accelerates downward due to the reduced
lift of the stalled wings, thus changing the direction of the relative wind.

--Gary

[Matt Whiting]

Jim Macklin wrote:
> Feel free to look me up on the FAA web. Certificated
> airplanes are designed to not fully stall the wing or the
> tail for that matter. But within the limits of what does
> happen, and without discussing wash-in, wash-out, twist,
> airfoil section changes, control stops, stick shaker and
> pullers, gust loading, accelerated stalls, mushing, getting
> a useable idea of what happens when the controls are applied
> smoothly, violently or the airplane breaks apart in flight.
>
> If the nose would always go down from a stall, spin chutes
> would not be required. If the airplane is abused in flight,
> it will do some pretty remarkable things. I know a Beech
> test pilot who wondered about what would happen in an E90 at
> cruise if you put the props into reverse. The airplane did
> not break, but they were reported to have changed their
> clothes after the flight. Same pilot tried the same thing
> in an F90 with the T-tail and nothing really uncontrollable
> happened.
>
> It is possible to design a wing that will stall, 100% across
> the entire span, but it won't be certified for civil use.
>
> If the tail surface reaches max lift (down-force) and you
> try to go slower, it will begin the stall as air flow
> reaches the critical angle of attack on the tail
> PROGRESSIVELY and the nose will drop because the moment
> between the CP and CG will not be countered by the tail
> forces. Do it slowly and the nose pitches down slowly.
> Pull a few Gs and the reaction is faster and the degree to
> which the stall progresses on the tail and wing is much
> faster because inertia will carry the aircraft past the
> critical angles at a higher kinetic energy level.

I've never seen this discussed in any book on aerodynamics that I've
ever read. Do you have even one credible reference to support your claims?

Matt

[Jim Macklin]

No, do I need a credible reference?



--
James H. Macklin
ATP,CFI,A&P

"Matt Whiting" > wrote in message
...
| Jim Macklin wrote:
| > Feel free to look me up on the FAA web. Certificated
| > airplanes are designed to not fully stall the wing or
the
| > tail for that matter. But within the limits of what
does
| > happen, and without discussing wash-in, wash-out, twist,
| > airfoil section changes, control stops, stick shaker and
| > pullers, gust loading, accelerated stalls, mushing,
getting
| > a useable idea of what happens when the controls are
applied
| > smoothly, violently or the airplane breaks apart in
flight.
| >
| > If the nose would always go down from a stall, spin
chutes
| > would not be required. If the airplane is abused in
flight,
| > it will do some pretty remarkable things. I know a
Beech
| > test pilot who wondered about what would happen in an
E90 at
| > cruise if you put the props into reverse. The airplane
did
| > not break, but they were reported to have changed their
| > clothes after the flight. Same pilot tried the same
thing
| > in an F90 with the T-tail and nothing really
uncontrollable
| > happened.
| >
| > It is possible to design a wing that will stall, 100%
across
| > the entire span, but it won't be certified for civil
use.
| >
| > If the tail surface reaches max lift (down-force) and
you
| > try to go slower, it will begin the stall as air flow
| > reaches the critical angle of attack on the tail
| > PROGRESSIVELY and the nose will drop because the moment
| > between the CP and CG will not be countered by the tail
| > forces. Do it slowly and the nose pitches down slowly.
| > Pull a few Gs and the reaction is faster and the degree
to
| > which the stall progresses on the tail and wing is much
| > faster because inertia will carry the aircraft past the
| > critical angles at a higher kinetic energy level.
|
| I've never seen this discussed in any book on aerodynamics
that I've
| ever read. Do you have even one credible reference to
support your claims?
|
| Matt

[Matt Whiting]

Jim Macklin wrote:
> No, do I need a credible reference?

Only if you want us to believe you as what you are saying goes against
everything most of us have seen published in the literature.

Matt

[Gary Drescher]

"Jim Macklin" > wrote in message
news:qcnmg.49388$ZW3.37903@dukeread04...
> "Matt Whiting" > wrote in message
> ...
>> I've never seen this discussed in any book on aerodynamics
>> that I've ever read. Do you have even one credible reference
>> to support your claims?
>
> No, do I need a credible reference?

Either that or a credible argument.

You keep insisting that a stalled wing (without a stalled tail) could not
produce a nose-down pitch at the stall onset, even though several of us have
explained how it could do so (by changing the direction of the relative
wind) and even though you haven't pointed out any flaw in that explanation.

And you keep insisting that a normally executed stall on a typical GA plane
can stall the tail before stalling the wing, even though Todd explained that
a stalled tail would produce an outside loop (if you were to keep the yoke
pulled back), and even though you haven't pointed out any flaw in that
explanation. (In fact, what happens in, say, a 172 with the yoke kept back
is just that the stall persists, because the tail sustains the wings' high
angle of attack--which couldn't happen if the tail were stalled as you
claim.)

--Gary

[Ron Rosenfeld]

On Tue, 20 Jun 2006 14:00:39 GMT, Larry Dighera > wrote:

>On Tue, 20 Jun 2006 07:36:13 -0400, Ron Rosenfeld
> wrote in
>::
>
>>On 20 Jun 2006 03:30:46 -0700, wrote:
>>
>>>Is it possible for an aircraft to stall and sink nose-up tail-down
>>>instead of pitching nose-down? Or does aircraft design inherently
>>>preclude that? :)
>>>
>>>Thanks in advance,
>>>
>>>Ramapriya
>>
>>Thinking about it simply, if the airplane is not generating lift, it should
>>fall with the heaviest end down. For most light GA a/c, the engine is up
>>front, so that end goes down first.
>
>You may recall, that Galileo Galilei (1564-1642) performed experiments
>to verify that heavier bodies do not fall faster than lighter ones,
>rather that they fall at the same rate, therefore your analysis is
>incorrect.
>
>While it is true, that an airplane in a vacuum will fall in any
>orientation, in the atmosphere, it is practically impossible to
>prevent the falling airplane's wings from providing some lift. Given
>an airplane correctly loaded within its weight and balance envelope,
>when the wing is generating lift, the center of lift is located behind
>the aircraft's center of gravity. The center of gravity acts as a
>fulcrum, and the lifting force aft of the CG is acting in the
>direction roughly upward, while the gradational force acts uniformly
>on the entire airplane in a downward direction resulting in the nose
>dropping as the aircraft was designed.

You're both getting into a more complicated, thoughtful (and accurate)
analysis than I.
Ron (EPM) (N5843Q, Mooney M20E) (CP, ASEL, ASES, IA)

[[email protected]]

george wrote:
> wrote:
> > Hi Marty,
> >
> > Rallyes are really fun, I miss mine from time to time. :-(
> >
> Great short field performance especially the 885

I had an 880, good performance for just 100hp(not talking speed)
Was thinking about buying an 885 but with avgas prices about $11.5/ us
gallon and not much faster than an 880......nah, not a good idea.

-Kees (D-EHNE)

[Marty Shapiro]

wrote in
oups.com:

>
> george wrote:
>> wrote:
>> > Hi Marty,
>> >
>> > Rallyes are really fun, I miss mine from time to time. :-(
>> >
>> Great short field performance especially the 885
>
> I had an 880, good performance for just 100hp(not talking speed)
> Was thinking about buying an 885 but with avgas prices about $11.5/ us
> gallon and not much faster than an 880......nah, not a good idea.
>
> -Kees (D-EHNE)
>
>

What is the speed of the 880? Was your 100hp engine the Rolls-Royce engine
that some of the early Rallye's had? The 885 (aka 235E) has the Lycoming
O540. I get 151 MPH (131 knots) at full throttle, but it burns almost 14
gph at that speed. I like the bigger engine for when I go to places like
Lake Tahoe in the summer as the density altitude at KTVL (6,264 MSL)can
exceed 11,000'. (Just for fun, I pulled a weather briefing for KTVL. The
DA at 12:53 AM PDT (07:53 Z) was 7,706' with an temperature of 11 C. The
forecast for tomorrow shows DA will be 10,000' with a temperature of 30 C.)

Of all the GA planes I've ever been in, either as pilot or passenger, the
Rallye is by far the most fun. My instrument instructor rated it second
best of all the aircraft he had ever piloted from both "fun to fly" and
outside visibility standpoints. Second place isn't too bad when the
aircraft he put in first place for these two factors was the F/A 18 Hornet
he flew when he was in the Navy.

--
Marty Shapiro
Silicon Rallye Inc.

(remove SPAMNOT to email me)

[[email protected]]

Hi Marty,

I think we are talking different 885s here.
As far as I remember the 885 is the light airframe with the 145 hp
O-300.
The 235 has the heavy airframe, I believe.
Well, does not matter really.

My 880 had the RR O-200, max speed about 90kts.

The only disadvantage of the Rallye I can think of is the difficulty to
get spare parts(never mind the costs, yikkes).

We used the 880 as a two-seater with a lot of luggage room.
The both of us plus full fuel and then we had 100# left for baggage,
and thats a lot if you have to carry it from and to the plane over
several 100 yards.

Having a sore back from hauling baggage is no more, I have a C150 now.

Cheers,
Kees.

[Jim Macklin]

I don't care what you believe. Maybe I just wanted a heated
discussion to start, or maybe there is another reason.
Factors to consider...
CG range approved
Actual operational CG
condition of the airfoils
pilot technique


Let see what this logic shows...
aircraft is slowed to near stalling speed by the application
of back pressure on the elevator which increases the down
force on the aircraft tail cone which levers the nose upward
by dynamically shifting the CG to a point behind the CP
which is the moment arm of the tail times the force produced
by the tail in an algebraic balance with the arm of the CG
and CP.

If the tail does not stall, to some degree, what tail down
force ceases to exist to maintain the nose up attitude? If
the wing is stalled does the lift not decrease and thus the
CP force decrease? Would that not reduce the moment needed
to rotate the nose downward to regain flying speed reduce
the angle of attack)?

FAR 23 has design limits for control degradation, the rudder
must be able to yaw the aircraft at a speed less than
lift-off speed, the elevator must be able to apply forces
and even the ailerons have limits. But when the aircraft is
stalled, out of ground effect, what force or forces change
that cause the nose to pitch downward? The wing is
producing less lift which means that the moment produced by
wing lift also decreases, reducing the nose down force. The
tail was supplying the force needed to establish the
attitude and what would cause THAT forced to be reduced if
it is not at least a stall (partial or complete) of the
elevator?

If the aircraft is held in a stalled condition, with the
elevator full back and the aircraft has a stall break, the
nose drops and then the nose pitches back up and the stall
break happens again and again in a cycle, the pilot keeping
the elevator full back and the wings level with rudder and
some aileron if the ailerons still function, what change in
forces on the aircraft is causing the cycle? Did the wing
regain lift or did the tail regain down-force?


--
James H. Macklin
ATP,CFI,A&P




"Matt Whiting" > wrote in message
...
| Jim Macklin wrote:
| > No, do I need a credible reference?
|
| Only if you want us to believe you as what you are saying
goes against
| everything most of us have seen published in the
literature.
|
| Matt

[Matt Whiting]

Jim Macklin wrote:

> I don't care what you believe.

Confirms my suspicion. You don't care about being correct either so no
need for further discussion. Ignorance is bliss.


Matt

[Gary Drescher]

"Jim Macklin" > wrote in message
news:Z6vmg.49402$ZW3.30156@dukeread04...
>"Matt Whiting" > wrote:
>> Jim Macklin wrote:
>>> No, do I need a credible reference?
>>
>> Only if you want us to believe you as what you are saying goes against
>> everything most of us have seen published in the literature.
>
> I don't care what you believe.

You're a CFI, so we care what your students are led to believe.

> Maybe I just wanted a heated discussion to start,

Uh, sure Jim. But there's been little heated discussion. Several of us have
just been patiently explaining to you an elementary aspect of aviation.

> If the tail does not stall, to some degree, what tail down
> force ceases to exist to maintain the nose up attitude?

That's a perfectly reasonable question, and it's been answered for you at
least five times in this thread. (Hint: search for "relative wind".) Each
time, you've simply *ignored* the answer without even *trying* to point out
any flaw in it.

Your approach to discussing aviation is the same as your approach to
discussing politics. In both domains, you're willing to engage in debate *as
long as it just rehashes material that's already familiar to you*. But as
soon as anyone raises an objection that you hadn't previously considered,
you just ignore it and retreat to familiar ground, repeating the claims that
the objection already defeated, making no attempt to refute the objection.

Unfortunately, that approach completely defeats the purpose of rational
discourse, because it renders your beliefs incorrigible. Perversely, you're
left with the illusion that you've sustained your position; but the reality
is that you merely went through the motions of rational discourse until just
before the point where a meaningful exchange of ideas would begin.

--Gary

[Matt Whiting]

Gary Drescher wrote:

> That's a perfectly reasonable question, and it's been answered for you at
> least five times in this thread. (Hint: search for "relative wind".) Each
> time, you've simply *ignored* the answer without even *trying* to point out
> any flaw in it.

It is pretty clear that he doesn't want to know the correct answer.
Yes, it is sad that he's a CFI and propogating these OWTs to his
students. It is even scarier than the system let him get to the ATP
level with this erroneous thinking.

Maybe I'll try to get a note to Barnaby Wainfan and see if he'll address
it in one of his future columns. I know he's dicussed stalls before,
but I'm not sure from this perspective of level of detail.

Matt

[Roy Smith]

"Jim Macklin" > wrote:
> I don't care what you believe. Maybe I just wanted a heated
> discussion to start

This is called being a troll, and is generally not something which most
people appreciate.

> aircraft is slowed to near stalling speed by the application
> of back pressure on the elevator which increases the down
> force on the aircraft tail cone which levers the nose upward
> by dynamically shifting the CG to a point behind the CP
> which is the moment arm of the tail times the force produced
> by the tail in an algebraic balance with the arm of the CG
> and CP.

This is gibberish. The CG doesn't shift unless stuff moves around in the
airplane. A study of shifting loads (such as fuel sloshing around in
half-full tanks) would be a fascinating but very complicated endeavor, and
not particularly germane to this discussion.

> If the tail does not stall, to some degree, what tail down
> force ceases to exist to maintain the nose up attitude?

OK, I explained this once, but I'll do it again, slowly, and more carefully.

Let's invent a hypothetical airplane where the main wing stalls at an alpha
(angle of attack, AOA) of 18 degrees, which happens to be a fairly typical
number for the kinds of wings most of us fly. Let's also imagine that it's
got a symmetric one-piece stabilator (such as found on an Archer), which
also stalls at 18 degrees (positive or negative). Vso for this plane is 60
kts (that's a pretty high value, but it makes the math easier

Now, let's put the plane at the edge of stall in a typical power-off stall
demonstration. The main wing AOA is 17.9 degrees. The yoke is almost all
the way back, and the stabilator is set at an AOA of -15 degrees. Power is
at idle, true airspeed is 50 kts, and you're maintaining altitude.

Now, pull back on the yoke just a bit more. The AOA increases to 18.1
degrees, and the main wing is now stalled. The wing is now producing less
lift than the airplane weighs, so it starts to accelerate downward. After
a short time, it's in a 100 fpm descent, but we're still holding the same
pitch attitude.

If you work the math, 60 KTAS and 100 fpm down works out to a glide slope
of just about -1 degree, which means the relative wind is now coming from 1
degree below the horizontal. Since the pitch angle hasn't changed, the AOA
of both the main wing and the tail will change by this same 1 degree. For
the main wing, that means the AOA has been driven from 18.1 degrees to 19.1
degrees; further into stall, and further reducing the amount of lift being
generated (increasing drag too, but that's a secondary issue).

Now, here's the interesting part. The tail has gone from -15 to -14. It's
moved further away from stall. But, it too, is producing less (downward)
lift because the AOA is reduced. Less downforce from the tail means the
nose will start to drop. No tail stall, just reduced downwards lift from
the tail due to decreased tail AOA caused by the downward motion of the
aircraft.

That's it, I'm done. If you really want to be a troll, enjoy yourself.





If
> the wing is stalled does the lift not decrease and thus the
> CP force decrease? Would that not reduce the moment needed
> to rotate the nose downward to regain flying speed reduce
> the angle of attack)?
>
> FAR 23 has design limits for control degradation, the rudder
> must be able to yaw the aircraft at a speed less than
> lift-off speed, the elevator must be able to apply forces
> and even the ailerons have limits. But when the aircraft is
> stalled, out of ground effect, what force or forces change
> that cause the nose to pitch downward? The wing is
> producing less lift which means that the moment produced by
> wing lift also decreases, reducing the nose down force. The
> tail was supplying the force needed to establish the
> attitude and what would cause THAT forced to be reduced if
> it is not at least a stall (partial or complete) of the
> elevator?
>
> If the aircraft is held in a stalled condition, with the
> elevator full back and the aircraft has a stall break, the
> nose drops and then the nose pitches back up and the stall
> break happens again and again in a cycle, the pilot keeping
> the elevator full back and the wings level with rudder and
> some aileron if the ailerons still function, what change in
> forces on the aircraft is causing the cycle? Did the wing
> regain lift or did the tail regain down-force?

[Roy Smith]

In article >,
Roy Smith > wrote:

> Power is
> at idle, true airspeed is 50 kts, and you're maintaining altitude.

Typo there, I meant to write "60".

[Roy Smith]

In article >,
Matt Whiting > wrote:

>
> It is pretty clear that he doesn't want to know the correct answer.
> Yes, it is sad that he's a CFI and propogating these OWTs to his
> students. It is even scarier than the system let him get to the ATP
> level with this erroneous thinking.

Getting your ATP only requires a few things:

1) Logging 1500 PIC hours. Anybody with enough time, money, and tenacity
can do that.

2) Passing a written test. Same comment as above.

3) Passing a flight test. This is a little harder, because it actually
requires some skill as a pilot, but I've known some very scary pilots who
have ATPs, so I gotta asuume it's not that tough.

I'm not impressed by people with ATPs, since having a clue is neither a
necessary nor sufficient condition for getting one.

[[email protected]]

Marty Shapiro wrote:
> wrote in
> oups.com:
>
> >
> > george wrote:
> >> wrote:
> >> > Hi Marty,
> >> >
> >> > Rallyes are really fun, I miss mine from time to time. :-(
> >> >
> >> Great short field performance especially the 885
> >
> > I had an 880, good performance for just 100hp(not talking speed)
> > Was thinking about buying an 885 but with avgas prices about $11.5/ us
> > gallon and not much faster than an 880......nah, not a good idea.
> >
> > -Kees (D-EHNE)
> >
> >
>
> What is the speed of the 880? Was your 100hp engine the Rolls-Royce engine
> that some of the early Rallye's had? The 885 (aka 235E) has the Lycoming
> O540. I get 151 MPH (131 knots) at full throttle, but it burns almost 14
> gph at that speed. I like the bigger engine for when I go to places like
> Lake Tahoe in the summer as the density altitude at KTVL (6,264 MSL)can
> exceed 11,000'. (Just for fun, I pulled a weather briefing for KTVL. The
> DA at 12:53 AM PDT (07:53 Z) was 7,706' with an temperature of 11 C. The
> forecast for tomorrow shows DA will be 10,000' with a temperature of 30 C.)
>
> Of all the GA planes I've ever been in, either as pilot or passenger, the
> Rallye is by far the most fun. My instrument instructor rated it second
> best of all the aircraft he had ever piloted from both "fun to fly" and
> outside visibility standpoints. Second place isn't too bad when the
> aircraft he put in first place for these two factors was the F/A 18 Hornet
> he flew when he was in the Navy.
>
> --
> Marty Shapiro
> Silicon Rallye Inc.
>
> (remove SPAMNOT to email me)
Hi Marty,

Max. cruising speed of my 880 was 90kts with indeed the RR O-200.
If I remember well the 885 is a Rallye with the light airframe and a
145hp O-300.
The 235 has the heavy airframe and 235hp.

We used the 880 as a two-seater with a large baggage compartment.
The two of us plus full fuel(100 liter) left 100# for baggage.
And that is a lot, especially when you have to carry it up and down an
airfield.
The last problem is solved, since last Friday I have a C150.

We fly in north west Europe, the highest field elevation I have landed
on so far was about 2000ft AMSL, normally I just plod along at 5000ft
or lower. So no need for a big engine(yet).

Happy and short landings,
Kees.

P.S. Bets are placed, at my flying club, how long it will take before I
get bored with that C150.

[Gary Drescher]

"T o d d P a t t i s t" > wrote in message
...
> Even for the wing, if the CP is behind the CG, and if the aircraft
> has any downward motion (which it will have as the wing
> loses lift), then drag pushes up at the CP which rotates the
> aircraft around the CG towards a nose down attitude.

Oops, that's right. Thanks for the correction.

--Gary

[Marty Shapiro]

wrote in
oups.com:

> Hi Marty,
>
> I think we are talking different 885s here.
> As far as I remember the 885 is the light airframe with the 145 hp
> O-300.
> The 235 has the heavy airframe, I believe.
> Well, does not matter really.
>
> My 880 had the RR O-200, max speed about 90kts.
>
> The only disadvantage of the Rallye I can think of is the difficulty to
> get spare parts(never mind the costs, yikkes).
>
> We used the 880 as a two-seater with a lot of luggage room.
> The both of us plus full fuel and then we had 100# left for baggage,
> and thats a lot if you have to carry it from and to the plane over
> several 100 yards.
>
> Having a sore back from hauling baggage is no more, I have a C150 now.
>
> Cheers,
> Kees.
>
>

Hi Kees -

Oooops. My mistake. I misread your model number as 895 and equated that
to the Rallye 235E, as the previous model, the MS-894 (aka Minerva) was the
Franklin 220hp powered Rallye. Sometimes I think MS & SOCATA had more
model numbers & names than they had aircraft.

Yes, the 235 has the heavy airframe, which includes 2 hardpoints on each
wing. I found some pictures on the web a few years ago showing 235's
outfitted as light fighters by a few Latin American countries. The only one
I could find today is about half-way down at
http://www.probertencyclopaedia.com/IRB.HTM

I am convinced SOCATA uses the aircraft's service ceiling as the floor for
parts prices.

---
Marty Shapiro
Silicon Rallye Inc.

(remove SPAMNOT to email me)

[Marty Shapiro]

wrote in
ups.com:

<snip>

>
> P.S. Bets are placed, at my flying club, how long it will take before
> I get bored with that C150.
>
>

You are flying! How can that be boring? As much fun as the Rallye? No,
but not boring.

--
Marty Shapiro
Silicon Rallye Inc.

(remove SPAMNOT to email me)

[Jim Macklin]

Sorry, I've been attempting to emulate the mental processes
of a Democrat.


"Gary Drescher" > wrote in message
. ..
| "Jim Macklin" > wrote
in message
| news:Z6vmg.49402$ZW3.30156@dukeread04...
| >"Matt Whiting" > wrote:
| >> Jim Macklin wrote:
| >>> No, do I need a credible reference?
| >>
| >> Only if you want us to believe you as what you are
saying goes against
| >> everything most of us have seen published in the
literature.
| >
| > I don't care what you believe.
|
| You're a CFI, so we care what your students are led to
believe.
|
| > Maybe I just wanted a heated discussion to start,
|
| Uh, sure Jim. But there's been little heated discussion.
Several of us have
| just been patiently explaining to you an elementary aspect
of aviation.
|
| > If the tail does not stall, to some degree, what tail
down
| > force ceases to exist to maintain the nose up attitude?
|
| That's a perfectly reasonable question, and it's been
answered for you at
| least five times in this thread. (Hint: search for
"relative wind".) Each
| time, you've simply *ignored* the answer without even
*trying* to point out
| any flaw in it.
|
| Your approach to discussing aviation is the same as your
approach to
| discussing politics. In both domains, you're willing to
engage in debate *as
| long as it just rehashes material that's already familiar
to you*. But as
| soon as anyone raises an objection that you hadn't
previously considered,
| you just ignore it and retreat to familiar ground,
repeating the claims that
| the objection already defeated, making no attempt to
refute the objection.
|
| Unfortunately, that approach completely defeats the
purpose of rational
| discourse, because it renders your beliefs incorrigible.
Perversely, you're
| left with the illusion that you've sustained your
position; but the reality
| is that you merely went through the motions of rational
discourse until just
| before the point where a meaningful exchange of ideas
would begin.
|
| --Gary
|
|

[george]

wrote:
> george wrote:
> > wrote:
> > > Hi Marty,
> > >
> > > Rallyes are really fun, I miss mine from time to time. :-(
> > >
> > Great short field performance especially the 885
>
> I had an 880, good performance for just 100hp(not talking speed)
> Was thinking about buying an 885 but with avgas prices about $11.5/ us
> gallon and not much faster than an 880......nah, not a good idea.
>
I soloed in a 880.
Main impression was those bloody slats on crosscountries keeping me
awake :-)
we had a 880 bore in with 4 sob while they were overloaded and playing
silly games

[[email protected]]

george wrote:
> wrote:
> > george wrote:
> > > wrote:
> > > > Hi Marty,
> > > >
> > > > Rallyes are really fun, I miss mine from time to time. :-(
> > > >
> > > Great short field performance especially the 885
> >
> > I had an 880, good performance for just 100hp(not talking speed)
> > Was thinking about buying an 885 but with avgas prices about $11.5/ us
> > gallon and not much faster than an 880......nah, not a good idea.
> >
> I soloed in a 880.
> Main impression was those bloody slats on crosscountries keeping me
> awake :-)
> we had a 880 bore in with 4 sob while they were overloaded and playing
> silly games

Now you mention the slats.
Last May I had my biannual and since I didn't have a plane I had to
rent one.
I can tell you that Rallye habbits do not work well in a Grob 115( a
German tupperware plane).
The instructor had enough remarks about my handling.
As on the first landing.
-He, pay attention, you are about to going to stall.
-Hmm, No I'm not.....Oh sh*t this stupid thing has no slats.

-Kees

[Gary Drescher]

"Jim Macklin" > wrote in message
news:BQBmg.49424$ZW3.24753@dukeread04...
> Sorry, I've been attempting to emulate the mental processes
> of a Democrat.

Putting aside the vacuous gibe, does that mean you now agree that your
account of stalls was incorrect? I'm genuinely concerned for the sake of
your students. If they were to believe you that an ordinary stall involves
stalling the tail, then they'd have reason to think that a tail stall isn't
a big deal. That would lead them to be less frightened than they should be
of circumstances that really can cause a tail stall (such as tail icing or a
too-forward CG).

--Gary

[Jim Macklin]

Maybe, I'm going to take a poll and see what I should do.

As far as my students go, they've been doing well for
decades. Many are or have been USAF, USN and some even hold
degrees as aeronautical engineers.


--
James H. Macklin
ATP,CFI,A&P

"Gary Drescher" > wrote in message
...
| "Jim Macklin" > wrote
in message
| news:BQBmg.49424$ZW3.24753@dukeread04...
| > Sorry, I've been attempting to emulate the mental
processes
| > of a Democrat.
|
| Putting aside the vacuous gibe, does that mean you now
agree that your
| account of stalls was incorrect? I'm genuinely concerned
for the sake of
| your students. If they were to believe you that an
ordinary stall involves
| stalling the tail, then they'd have reason to think that a
tail stall isn't
| a big deal. That would lead them to be less frightened
than they should be
| of circumstances that really can cause a tail stall (such
as tail icing or a
| too-forward CG).
|
| --Gary
|
|

[Jose]

> circumstances that really can cause a tail stall (such as [...] a
> too-forward CG).

Ding.

Obvious once I thought about it (duh!), but it had never occured to me
before, and nobody had ever mentioned it in my training. How far
further forward would the CG need to be to cause a tail stall in normal
flight attitudes?

Jose
--
The monkey turns the crank and thinks he's making the music.
for Email, make the obvious change in the address.

[Gary Drescher]

"Jose" > wrote in message
.net...
>> circumstances that really can cause a tail stall (such as [...] a
>> too-forward CG).
>
> Ding.
>
> Obvious once I thought about it (duh!), but it had never occured to me
> before, and nobody had ever mentioned it in my training. How far further
> forward would the CG need to be to cause a tail stall in normal flight
> attitudes?

Although I haven't done the calculation, I'd be surprised if a typical GA
plane could tail-stall at a normal in-flight angle of attack no matter how
far forward you had the CG (unless you were to tie some cinder blocks to the
nose gear or something). The danger would come during the landing flare, or
if you tried to do slow flight or stall practice, or if turbulence were to
abruptly increase the AoA.

--Gary

[Gary Drescher]

"Jim Macklin" > wrote in message
news:zZTmg.49464$ZW3.45524@dukeread04...
> Maybe, I'm going to take a poll and see what I should do.
>
> As far as my students go, they've been doing well for
> decades. Many are or have been USAF, USN and some even hold
> degrees as aeronautical engineers.

Yes, I'd expect most of your students to survive the confusion--either
because they know better than to accept your model (try asking the AEs about
it), or because they don't happen to consider the ramifications I mentioned.

Still, there's no reason to impose the small but real danger that comes from
teaching a false, confusing model of stalls when a correct model is readily
available instead.

--Gary

> James H. Macklin
> ATP,CFI,A&P
>
> "Gary Drescher" > wrote in message
> ...
> | "Jim Macklin" > wrote
> in message
> | news:BQBmg.49424$ZW3.24753@dukeread04...
> | > Sorry, I've been attempting to emulate the mental
> processes
> | > of a Democrat.
> |
> | Putting aside the vacuous gibe, does that mean you now
> agree that your
> | account of stalls was incorrect? I'm genuinely concerned
> for the sake of
> | your students. If they were to believe you that an
> ordinary stall involves
> | stalling the tail, then they'd have reason to think that a
> tail stall isn't
> | a big deal. That would lead them to be less frightened
> than they should be
> | of circumstances that really can cause a tail stall (such
> as tail icing or a
> | too-forward CG).
> |
> | --Gary
> |
> |
>
>

[Jim Macklin]

Did I ever say that I had taught any particular theory to
any student?

If an airplane was only a wing and there was no tail, would
a high speed computer monitoring angle of attack,
differential pressure and able to use spoilers, slats,
weight-shift, boundary layer control, etc be able to fly the
wing? Would it make a difference if the wing was straight
or swept?

If dimples make a golf ball fly further and stitches make a
baseball curve, why do airplanes have neither? Why do some
people think that space aliens built the pyramids or that
all the tall buildings were built with demolition charges so
the government could bring down the buildings in a phony
terrorist attack?

Lift varies with the square of the airspeed, at the same
angle of attack, double the speed and the lift increases by
four times. Assuming a linear change in lift with changes
in angle of attack, if the aircraft is slowed by 50% and the
angle of attack is increased to compensate, how much is
that? If a train leaves Boston at midnight headed for
Chicago and a Mexican crosses the border at the same time,
when will you hub caps be stolen in St. Louis?

If a student pilot departs an airport in Class B airspace
and flies 1,000 miles in Class A airspace before landing at
an airport in Class G airspace, is the student pilot in
violation of any regulation? Has any regulation been
violated? Did the flight leave Portland, OR and go to
Alaska? Was the student pilot just a passenger on an
airline?

Is Buffy the Vampire Slayer based on fact?



"Gary Drescher" > wrote in message
...
| "Jim Macklin" > wrote
in message
| news:zZTmg.49464$ZW3.45524@dukeread04...
| > Maybe, I'm going to take a poll and see what I should
do.
| >
| > As far as my students go, they've been doing well for
| > decades. Many are or have been USAF, USN and some even
hold
| > degrees as aeronautical engineers.
|
| Yes, I'd expect most of your students to survive the
confusion--either
| because they know better than to accept your model (try
asking the AEs about
| it), or because they don't happen to consider the
ramifications I mentioned.
|
| Still, there's no reason to impose the small but real
danger that comes from
| teaching a false, confusing model of stalls when a correct
model is readily
| available instead.
|
| --Gary
|
| > James H. Macklin
| > ATP,CFI,A&P
| >
| > "Gary Drescher" > wrote in
message
| > ...
| > | "Jim Macklin" >
wrote
| > in message
| > | news:BQBmg.49424$ZW3.24753@dukeread04...
| > | > Sorry, I've been attempting to emulate the mental
| > processes
| > | > of a Democrat.
| > |
| > | Putting aside the vacuous gibe, does that mean you now
| > agree that your
| > | account of stalls was incorrect? I'm genuinely
concerned
| > for the sake of
| > | your students. If they were to believe you that an
| > ordinary stall involves
| > | stalling the tail, then they'd have reason to think
that a
| > tail stall isn't
| > | a big deal. That would lead them to be less frightened
| > than they should be
| > | of circumstances that really can cause a tail stall
(such
| > as tail icing or a
| > | too-forward CG).
| > |
| > | --Gary
| > |
| > |
| >
| >
|
|

[Gary Drescher]

"Jim Macklin" > wrote in message
news:q2Ymg.49475$ZW3.39824@dukeread04...
> Did I ever say that I had taught any particular theory to
> any student?

Nope. You said that you're a CFI and that you believe stalls work in a
particular way. Most CFIs teach what they believe to be true about
fundamental aviation matters. Do you do otherwise?

--Gary

[Roy Smith]

In article >,
Gary Drescher > wrote:
>"Jim Macklin" > wrote in message
>news:q2Ymg.49475$ZW3.39824@dukeread04...
>> Did I ever say that I had taught any particular theory to
>> any student?
>
>Nope. You said that you're a CFI and that you believe stalls work in a
>particular way. Most CFIs teach what they believe to be true about
>fundamental aviation matters. Do you do otherwise?

I predict what I'm about to write will be unpopular, but what the heck.

I certainly agree that any CFI should have a good (and correct)
understanding of the aerodynamics of stalls. That being said, all
your typical pilot really has to know is:

1) Stalls happen when the wing exceeds the critial AOA.

2) This can happen at any airspeed and attitude, but for most people
who fly near 1G almost all the time, "don't get too slow and don't
point the nose up too high" is a pretty good rule of thumb.

3) You can recognize a stall by mushy controls, stall warner going
off, buffet, and/or inability to maintain altitude.

4) You break the stall by reducing the AOA. Again, for most people
who live near 1G and the dirty side down almost all the time, that
means "push the yoke forward".

If a student believes the tailplane stalls at the stall break, and
that's what causes the nose to pitch down, it's not going to kill
them. It's wrong, but it's an esoteric wrong and people don't get
killed by esoteric wrongs.

Not being able to figure out if you have enough fuel to get where
you're going will kill you. Not knowing how to obtain and understand
accurate weather information will kill you. Not understanding that
stomping on the inside rudder to fix a misjudged base-to-final turn
can cause a stall/spin will kill you.

Not understanding the subtle details of the aerodynamics of a stall
such as we've been discussing here may get you a lower score on a
written test, or even make you flunk a CFI oral exam, or get roasted
on usenet, but it won't kill you, and it won't kill your students
either.

OK, you all can beat me up now.

Anyway, everybody really knows that stall recovery works like this:

1) Stall warning buzzer goes off.

2) Pilot instinctively puts his hands to his ears to block out the
annoying noise.

3) As soon as his hands are removed from the yoke, the plane recovers
on its own.

[Gary Drescher]

"Roy Smith" > wrote in message
...
> In article >,
> If a student believes the tailplane stalls at the stall break, and
> that's what causes the nose to pitch down, it's not going to kill
> them. It's wrong, but it's an esoteric wrong and people don't get
> killed by esoteric wrongs.

Roy, I agree with your general point. Much of the detail about how lift and
stalls work is of interest to engineers and physicists, but not to pilots as
such. And I agree that it's useful to present student pilots with as simple
a model as possible that supports the right conclusions about how to fly.
(Students who happen to be curious can learn more complex, more accurate
models.)

Still, I think it's useful to include a bit more information than the points
you enumerated. In particular, some reference to the Bernoulli aspect of
lift, and the separation of the boundary layer during a stall, helps make
clear why the condition of the upper wing surface is important (and why a
thin layer of frost on the upper surface can make it dangerous to take off,
for example).

Similarly, Jim's false model of stalls has some ramifications that are of
interest to pilots. In particular, if Jim's model were correct, then pilots
would have no reason to consider tail stalls more worrisome than normal
stalls (because normal stalls would *be* tail stalls). But Jim's model is
wrong, and a student who took it seriously could get into trouble. That
probably wouldn't happen (because a student who could figure out that
ramification could probably also figure out what's wrong with Jim's
explanation), but it's still an unnecessary risk.

--Gary

[Jim Macklin]

All the time, on the Internet.



"Gary Drescher" > wrote in message
. ..
| "Jim Macklin" > wrote
in message
| news:q2Ymg.49475$ZW3.39824@dukeread04...
| > Did I ever say that I had taught any particular theory
to
| > any student?
|
| Nope. You said that you're a CFI and that you believe
stalls work in a
| particular way. Most CFIs teach what they believe to be
true about
| fundamental aviation matters. Do you do otherwise?
|
| --Gary
|
|

[Matt Whiting]

Roy Smith wrote:

> In article >,
> Matt Whiting > wrote:
>
>
>>It is pretty clear that he doesn't want to know the correct answer.
>>Yes, it is sad that he's a CFI and propogating these OWTs to his
>>students. It is even scarier than the system let him get to the ATP
>>level with this erroneous thinking.
>
>
> Getting your ATP only requires a few things:
>
> 1) Logging 1500 PIC hours. Anybody with enough time, money, and tenacity
> can do that.
>
> 2) Passing a written test. Same comment as above.

I'd have thought the written would have at least a few questions about
aerodynamics.


> 3) Passing a flight test. This is a little harder, because it actually
> requires some skill as a pilot, but I've known some very scary pilots who
> have ATPs, so I gotta asuume it's not that tough.
>
> I'm not impressed by people with ATPs, since having a clue is neither a
> necessary nor sufficient condition for getting one.

I'm less impressed than I was a few days ago that's for sure!


Matt

[Matt Whiting]

Roy Smith wrote:

> In article >,
> Gary Drescher > wrote:
>
>>"Jim Macklin" > wrote in message
>>news:q2Ymg.49475$ZW3.39824@dukeread04...
>>
>>>Did I ever say that I had taught any particular theory to
>>>any student?
>>
>>Nope. You said that you're a CFI and that you believe stalls work in a
>>particular way. Most CFIs teach what they believe to be true about
>>fundamental aviation matters. Do you do otherwise?
>
>
> I predict what I'm about to write will be unpopular, but what the heck.
>
> I certainly agree that any CFI should have a good (and correct)
> understanding of the aerodynamics of stalls. That being said, all
> your typical pilot really has to know is:

Roy, the topic of discussion has nothing to do with it. It is the
attitude that accepts being wrong and teaching wrong as not being wrong
that is wrong!
:-)

Matt

[Jim Macklin]

I have found that when I give a perfectly correct and
complete answer, there is nothing left to say and the thread
dries up. I just tried and succeeded in stimulating the
conversation.

BTW, does anybody know how to explain the left hand rule for
electricity or is it the right hand rule?



--
James H. Macklin
ATP,CFI,A&P

"Matt Whiting" > wrote in message
...
| Roy Smith wrote:
|
| > In article
>,
| > Gary Drescher > wrote:
| >
| >>"Jim Macklin" >
wrote in message
| >>news:q2Ymg.49475$ZW3.39824@dukeread04...
| >>
| >>>Did I ever say that I had taught any particular theory
to
| >>>any student?
| >>
| >>Nope. You said that you're a CFI and that you believe
stalls work in a
| >>particular way. Most CFIs teach what they believe to be
true about
| >>fundamental aviation matters. Do you do otherwise?
| >
| >
| > I predict what I'm about to write will be unpopular, but
what the heck.
| >
| > I certainly agree that any CFI should have a good (and
correct)
| > understanding of the aerodynamics of stalls. That being
said, all
| > your typical pilot really has to know is:
|
| Roy, the topic of discussion has nothing to do with it.
It is the
| attitude that accepts being wrong and teaching wrong as
not being wrong
| that is wrong!
| :-)
|
| Matt

[Matt Whiting]

Jim Macklin wrote:

> I have found that when I give a perfectly correct and
> complete answer, there is nothing left to say and the thread
> dries up. I just tried and succeeded in stimulating the
> conversation.
>
> BTW, does anybody know how to explain the left hand rule for
> electricity or is it the right hand rule?

Jim, your doctor prescribed those meds for a reason. Don't stop taking
them again.

Matt

[Roy Smith]

In article >,
Matt Whiting > wrote:

> > 2) Passing a written test. Same comment as above.
>
> I'd have thought the written would have at least a few questions about
> aerodynamics.

I'm sure it does, but you don't need to know anything about aerodynamics to
get the questions right. You just need to have memorized the right answers.

I took my instrument written over 10 years ago. I don't know squat about
MLS, but I can still tell you that for all the MLS questions on the test
(at the time), the correct answer is the one with the biggest number. Once
I spotted that pattern, I didn't waste any additional brain cells on MLS.

[Jim Macklin]

Actually, I found a bottle of antibiotic and it has cleared
up my sinuses. But other than that, I'm drug free.


Forty years ago, when I cut my leg in the horse barn, I did
use some of the horse medicine rather than go to a people
doctor to get a shot. I just gave myself a few ccs of
Combiotic (a mixture of two kinds of antibiotic also
approved for people as well as cats, dogs and horses). I
have also done a little surgery to remove things like nails
in my arms, hands and legs, farm work can be dangerous. But
all my original parts are still attached and fully
functional, so I must have done it well enough.

You'd probably criticize Wolfgang Langewiesche for calling
elevators "flippers" or wonder like me, whether General
McCauliffe really said "Nuts" or used some other common
word(s).


--
James H. Macklin
ATP,CFI,A&P





"Matt Whiting" > wrote in message
...
| Jim Macklin wrote:
|
| > I have found that when I give a perfectly correct and
| > complete answer, there is nothing left to say and the
thread
| > dries up. I just tried and succeeded in stimulating the
| > conversation.
| >
| > BTW, does anybody know how to explain the left hand rule
for
| > electricity or is it the right hand rule?
|
| Jim, your doctor prescribed those meds for a reason.
Don't stop taking
| them again.
|
| Matt

[Peter Duniho]

"Roy Smith" > wrote in message
...
> I predict what I'm about to write will be unpopular, but what the heck.
> [...]

I doubt it would be that unpopular. There's some good common sense in
there.

However:

There's a difference between saying "I don't care what happens when an
airplane stalls" and saying "I don't care that I have the wrong belief about
what happens when an airplane stalls". The former is not a serious problem,
as you say.

But a person who *believes* they actually understand the esoterics of a
stall, but who actually does not, and who refuses to listen to educated
people who DO actually understand those esoterics, that's a dangerous
person, especially as an instructor. Not only are they conveying the
*wrong* information (as opposed to not conveying information at all), they
are exhibiting a personal attitude that is extremely dangerous, to
themselves and to others. Aviation has no place for people who have no
ability to reflect on their own beliefs and correct them when they have been
demonstrated to be incorrect.

I will also mention that Gary's point about the connection between the
incorrect theory of stalling that Jim is presenting and the genuine hazard
of a tailplane stall is quite relevant. It's true that most pilots will
never get themselves into a situation where a tailplane stall is an issue,
but knowing the correct theory may help a pilot avoid those situations, or
correctly mitigate such situations if they wind up in one (whether
accidently or through poor judgment).

In other words, when you write:

> If a student believes the tailplane stalls at the stall break, and
> that's what causes the nose to pitch down, it's not going to kill
> them.

I'm not convinced I agree with that 100%. It's true that that belief has a
low likelihood of killing a pilot. But it could, in the right (wrong)
situation.

Pete

[Peter Duniho]

"Jose" > wrote in message
.net...
>> circumstances that really can cause a tail stall (such as [...] a
>> too-forward CG).
>
> Ding.
>
> Obvious once I thought about it (duh!), but it had never occured to me
> before, and nobody had ever mentioned it in my training. How far further
> forward would the CG need to be to cause a tail stall in normal flight
> attitudes?

That all depends on the airplane, whether it's also overloaded, and as Gary
points out, what maneuvering is going on.

A pilot should not be loading the airplane outside the certificated weight &
balance envelope anyway, but understanding that a tailplane stall is NOT a
"normal", recoverable event in the way that a wing stall is could make the
difference between a pilot not pushing those boundaries, and doing so and
winding up dead.

Pete

[Jose]

> but for most people
> who fly near 1G almost all the time, "don't get too slow and don't
> point the nose up too high" is a pretty good rule of thumb.

Most pilots do steep turns sometimes. At least they ought to. Relying
on that rule, and the "mushy" rule, will cause a surprise.

> If a student believes the tailplane stalls at the stall break, and
> that's what causes the nose to pitch down, it's not going to kill
> them. It's wrong, but it's an esoteric wrong and people don't get
> killed by esoteric wrongs.

It's not so esoteric for an instrument pilot in the Northeast.

> Not being able to figure out if you have enough fuel to get where
> you're going will kill you. Not knowing how to obtain and understand
> accurate weather information will kill you. Not understanding that
> stomping on the inside rudder to fix a misjudged base-to-final turn
> can cause a stall/spin will kill you.

Yes, yes, and just a moment. "Not understanding" and "not knowing" are
two different things. Understanding implies knowing -why-. We are
talking about knowing -why- (something else). What's the difference?

> Anyway, everybody really knows that stall recovery works like this:
>
> 1) Stall warning buzzer goes off.
>
> 2) Pilot instinctively puts his hands to his ears to block out the
> annoying noise.
>
> 3) As soon as his hands are removed from the yoke, the plane recovers
> on its own.

LOL :)

Jose
--
The monkey turns the crank and thinks he's making the music.
for Email, make the obvious change in the address.

[Jose]

> BTW, does anybody know how to explain the left hand rule for
> electricity or is it the right hand rule?

Yes. I do.

Electricity is made of two parts - electrons and French particles. They
are clearly opposites.

Electrons obey the lEft hand rule. That's because they are liberals -
(liberal begins with an L). They are lightweights compared to other
elementary particles (lightweight begins with an L) and pretty much go
wherever you push them. Protons on the other hand need a lot more push,
and neutrons don't give a damn - they go where they will.

The French do everything differently - they even have a different name
for current - they call it something like "Intensity". Alas, this
abberation survives in the equation V=IR, where I means "current" (or
"amount of French particles") French particles, being nationalistic,
follow the rIght hand rule.

Many people call them Revolutionary particles (revolutionary begins with
R), ostensibly because of the French Revolution. Actually, this makes a
little sense, since in a simple closed electrical circut the Rrench
particles are in fact revolving (around the circuit). But then so do
the electrons, but they go the other way.

This causes quite a commotion, having the French particles going
opposite the Electrons, and they do not get along with each other. They
give each other the finger as they go by, and you can tell which is
which by the kind of finger it gives you.

French particles, or "revolutionary particles", use their rIght hand and
give a very Intense finger - they stick out their thumb and let their
fingers curl showing their contempt of the whole situation. Since the
French (at least French women) have a very magnetic personality, this
creates a magnetic field which follows the way the other fingers curl
around the rIght hand.

Elecrons use their lEft hand, Liberating their thumb and whipping their
other fingers around like a fist. Since Liberals advocate free Lunches,
people are attracted to them, following where their fingers point.
Since it's the LEft hand, this goes opposite from the way the French (or
Revolutionary) particles point. Fortunately, the kind of people that
follow the French are different from the kind of people that follow the
Liberals, and it all works out. Only people get confused - the
particles all know where to go.

Jose
--
The monkey turns the crank and thinks he's making the music.
for Email, make the obvious change in the address.

[Don Tuite]

On Sat, 24 Jun 2006 03:59:00 GMT, Jose >
wrote:

>> BTW, does anybody know how to explain the left hand rule for
>> electricity or is it the right hand rule?
>
>Yes. I do.
>
>Electricity is made of two parts - electrons and French particles. They
>are clearly opposites.
>
>Electrons obey the lEft hand rule. That's because they are liberals -
>(liberal begins with an L). They are lightweights compared to other
>elementary particles (lightweight begins with an L) and pretty much go
>wherever you push them. Protons on the other hand need a lot more push,
>and neutrons don't give a damn - they go where they will.
>
>The French do everything differently - they even have a different name
>for current - they call it something like "Intensity". Alas, this
>abberation survives in the equation V=IR, where I means "current" (or
>"amount of French particles") French particles, being nationalistic,
>follow the rIght hand rule.
>
>Many people call them Revolutionary particles (revolutionary begins with
>R), ostensibly because of the French Revolution. Actually, this makes a
>little sense, since in a simple closed electrical circut the Rrench
>particles are in fact revolving (around the circuit). But then so do
>the electrons, but they go the other way.
>
>This causes quite a commotion, having the French particles going
>opposite the Electrons, and they do not get along with each other. They
>give each other the finger as they go by, and you can tell which is
>which by the kind of finger it gives you.
>
>French particles, or "revolutionary particles", use their rIght hand and
>give a very Intense finger - they stick out their thumb and let their
>fingers curl showing their contempt of the whole situation. Since the
>French (at least French women) have a very magnetic personality, this
>creates a magnetic field which follows the way the other fingers curl
>around the rIght hand.
>
>Elecrons use their lEft hand, Liberating their thumb and whipping their
>other fingers around like a fist. Since Liberals advocate free Lunches,
>people are attracted to them, following where their fingers point.
>Since it's the LEft hand, this goes opposite from the way the French (or
>Revolutionary) particles point. Fortunately, the kind of people that
>follow the French are different from the kind of people that follow the
>Liberals, and it all works out. Only people get confused - the
>particles all know where to go.
>
Somehow this can be extended to explain conventional current, I'm
sure.

And eagerly waiting.

Don

[Jim Macklin]

Perfectly clear to me. That French particle thing must be
why they count by coulombs.


--
James H. Macklin
ATP,CFI,A&P

"Jose" > wrote in message
. com...
|> BTW, does anybody know how to explain the left hand rule
for
| > electricity or is it the right hand rule?
|
| Yes. I do.
|
| Electricity is made of two parts - electrons and French
particles. They
| are clearly opposites.
|
| Electrons obey the lEft hand rule. That's because they
are liberals -
| (liberal begins with an L). They are lightweights
compared to other
| elementary particles (lightweight begins with an L) and
pretty much go
| wherever you push them. Protons on the other hand need a
lot more push,
| and neutrons don't give a damn - they go where they will.
|
| The French do everything differently - they even have a
different name
| for current - they call it something like "Intensity".
Alas, this
| abberation survives in the equation V=IR, where I means
"current" (or
| "amount of French particles") French particles, being
nationalistic,
| follow the rIght hand rule.
|
| Many people call them Revolutionary particles
(revolutionary begins with
| R), ostensibly because of the French Revolution.
Actually, this makes a
| little sense, since in a simple closed electrical circut
the Rrench
| particles are in fact revolving (around the circuit). But
then so do
| the electrons, but they go the other way.
|
| This causes quite a commotion, having the French particles
going
| opposite the Electrons, and they do not get along with
each other. They
| give each other the finger as they go by, and you can tell
which is
| which by the kind of finger it gives you.
|
| French particles, or "revolutionary particles", use their
rIght hand and
| give a very Intense finger - they stick out their thumb
and let their
| fingers curl showing their contempt of the whole
situation. Since the
| French (at least French women) have a very magnetic
personality, this
| creates a magnetic field which follows the way the other
fingers curl
| around the rIght hand.
|
| Elecrons use their lEft hand, Liberating their thumb and
whipping their
| other fingers around like a fist. Since Liberals advocate
free Lunches,
| people are attracted to them, following where their
fingers point.
| Since it's the LEft hand, this goes opposite from the way
the French (or
| Revolutionary) particles point. Fortunately, the kind of
people that
| follow the French are different from the kind of people
that follow the
| Liberals, and it all works out. Only people get
confused - the
| particles all know where to go.
|
| Jose
| --
| The monkey turns the crank and thinks he's making the
music.
| for Email, make the obvious change in the address.

[Jim Macklin]

It is actually all magic. The Earth rotates at 1,000 mph at
the equator and the core is a little slower and at the same
time the Earth is in orbit around the Sun. It is producing
eclectic currents in the core and crust and trying to
balance these with electrical discharges for the
entertainment of the gods. This is generated as an AC
current on a very slow cycle, which causes the Earth's
magnetic field to change over a periods of hundreds of
years. There is an exchange of French particles and
electrons between the Sun and the planets. The Sun is our
local power source but like all circuits is effected by the
other objects in the system. The Sun can increase the
output of energy and this will effect all the planets. For
instance, the Earth and other planets are a little warmer
and our Rovers on Mars have been getting more solar power
than was expected so they have continued to operate past
their designed life expectancy.
As long as the proper bribes are paid to the engineers,
chemists and IBEW the magic will continue to work. NASA has
experimented with collecting free electricity in space by
dragging a long wire in the Earth's magnetic field, but
their fishing reel jammed and the wire over-heated and
broke. Someday they will make a real long extension cord
and send the power from orbit to Las Vegas so the lights can
burn as long as the Earth turns.
If you look in the building codes, the left hand rule is
that the light switch is to be located on the left hand when
the door hinges are on the right as you leave the room and
the reverse if the door is swung from the other side.

No really, the left and right hand rules tell you how to use
a compass to determine positive and negative leads in a DC
circuit without a standard meter. Is it true that if an
electrician is well grounded in his trade, he won't last
long, but if he is insolated from the reality of electricity
he can last nearly forever?

I plan on becoming serious sometime in July when I win the
lottery.


"Don Tuite" > wrote in
message ...
| On Sat, 24 Jun 2006 03:59:00 GMT, Jose
>
| wrote:
|
| >> BTW, does anybody know how to explain the left hand
rule for
| >> electricity or is it the right hand rule?
| >
| >Yes. I do.
| >
| >Electricity is made of two parts - electrons and French
particles. They
| >are clearly opposites.
| >
| >Electrons obey the lEft hand rule. That's because they
are liberals -
| >(liberal begins with an L). They are lightweights
compared to other
| >elementary particles (lightweight begins with an L) and
pretty much go
| >wherever you push them. Protons on the other hand need a
lot more push,
| >and neutrons don't give a damn - they go where they will.
| >
| >The French do everything differently - they even have a
different name
| >for current - they call it something like "Intensity".
Alas, this
| >abberation survives in the equation V=IR, where I means
"current" (or
| >"amount of French particles") French particles, being
nationalistic,
| >follow the rIght hand rule.
| >
| >Many people call them Revolutionary particles
(revolutionary begins with
| >R), ostensibly because of the French Revolution.
Actually, this makes a
| >little sense, since in a simple closed electrical circut
the Rrench
| >particles are in fact revolving (around the circuit).
But then so do
| >the electrons, but they go the other way.
| >
| >This causes quite a commotion, having the French
particles going
| >opposite the Electrons, and they do not get along with
each other. They
| >give each other the finger as they go by, and you can
tell which is
| >which by the kind of finger it gives you.
| >
| >French particles, or "revolutionary particles", use their
rIght hand and
| >give a very Intense finger - they stick out their thumb
and let their
| >fingers curl showing their contempt of the whole
situation. Since the
| >French (at least French women) have a very magnetic
personality, this
| >creates a magnetic field which follows the way the other
fingers curl
| >around the rIght hand.
| >
| >Elecrons use their lEft hand, Liberating their thumb and
whipping their
| >other fingers around like a fist. Since Liberals
advocate free Lunches,
| >people are attracted to them, following where their
fingers point.
| >Since it's the LEft hand, this goes opposite from the way
the French (or
| >Revolutionary) particles point. Fortunately, the kind of
people that
| >follow the French are different from the kind of people
that follow the
| >Liberals, and it all works out. Only people get
confused - the
| >particles all know where to go.
| >
| Somehow this can be extended to explain conventional
current, I'm
| sure.
|
| And eagerly waiting.
|
| Don
|

[Jose]

> Somehow this can be extended to explain conventional current, I'm
> sure.
> And eagerly waiting.

The French particles take care of the Intensity of what Americans call
"current".

I don't know anything about "conventional current"; that would seem to
be an oxymoron. By the time a convention is convened, the news is no
longer current, and in terms of electricity, to get it at a convention
costs too much, so little research has been done there. The only
exception is sales conventions, where the electricity is palpable, and
nobody is grounded.

Interestingly, in semiconductor physics, French particles are called
"holes". I'll let you draw your own conclusions.

Jose
--
The monkey turns the crank and thinks he's making the music.
for Email, make the obvious change in the address.

[Dave Stadt]

"Don Tuite" > wrote in message
...
> On Sat, 24 Jun 2006 03:59:00 GMT, Jose >
> wrote:
>
>>> BTW, does anybody know how to explain the left hand rule for
>>> electricity or is it the right hand rule?
>>
>>Yes. I do.
>>
>>Electricity is made of two parts - electrons and French particles. They
>>are clearly opposites.
>>
>>Electrons obey the lEft hand rule. That's because they are liberals -
>>(liberal begins with an L). They are lightweights compared to other
>>elementary particles (lightweight begins with an L) and pretty much go
>>wherever you push them. Protons on the other hand need a lot more push,
>>and neutrons don't give a damn - they go where they will.
>>
>>The French do everything differently - they even have a different name
>>for current - they call it something like "Intensity". Alas, this
>>abberation survives in the equation V=IR, where I means "current" (or
>>"amount of French particles") French particles, being nationalistic,
>>follow the rIght hand rule.
>>
>>Many people call them Revolutionary particles (revolutionary begins with
>>R), ostensibly because of the French Revolution. Actually, this makes a
>>little sense, since in a simple closed electrical circut the Rrench
>>particles are in fact revolving (around the circuit). But then so do
>>the electrons, but they go the other way.
>>
>>This causes quite a commotion, having the French particles going
>>opposite the Electrons, and they do not get along with each other. They
>>give each other the finger as they go by, and you can tell which is
>>which by the kind of finger it gives you.
>>
>>French particles, or "revolutionary particles", use their rIght hand and
>>give a very Intense finger - they stick out their thumb and let their
>>fingers curl showing their contempt of the whole situation. Since the
>>French (at least French women) have a very magnetic personality, this
>>creates a magnetic field which follows the way the other fingers curl
>>around the rIght hand.
>>
>>Elecrons use their lEft hand, Liberating their thumb and whipping their
>>other fingers around like a fist. Since Liberals advocate free Lunches,
>>people are attracted to them, following where their fingers point.
>>Since it's the LEft hand, this goes opposite from the way the French (or
>>Revolutionary) particles point. Fortunately, the kind of people that
>>follow the French are different from the kind of people that follow the
>>Liberals, and it all works out. Only people get confused - the
>>particles all know where to go.
>>
> Somehow this can be extended to explain conventional current, I'm
> sure.
>
> And eagerly waiting.
>
> Don

He is actually very close to explaining conventional and electron current
flow.

[Morgans]

"Kingfish" > wrote

> I would like to see two humans fit under the panel in a Twinkie. Were
> these guys circus freaks??

I would say that if you thought you were about to die, but could be saved by
crawling into my back pocket, you would probably find a way to fit! <g>
--
Jim in NC

[Jim Macklin]

Are you talking about the Iraq war and the war on terror?



"T o d d P a t t i s t" > wrote
in message
...
| (Roy Smith) wrote:
|
| >I predict what I'm about to write will be unpopular, but
what the heck.
|
| It didn't turn out to be very unpopular :-) I don't have
| any problem with it either. Instructors *should* focus on
| teaching what the student needs to know to avoid getting
| killed. It's perfectly OK to say - that's an arcane bit
of
| knowledge that may be technically interesting, but it's
not
| fundamental to safety, and I don't know the answer.
|
| It's also OK to be wrong, particularly on the arcane bits.
| We all suffer from that to a greater or lesser degree.
|
| My problem comes from what looks like an attitude that
it's
| OK to teach something wrong in the face of everyone else
| saying it's wrong, and to stubbornly stick to the wrong
| answer without questioning why others are saying it's
wrong
| and, apparently, without being open to looking for the
right
| answer. All of the effort put into defending the wrong
| answer could have and should have been sufficient to get
the
| right answer. In this case, I completely agree it's not
that
| critical, but it does make you wonder whether the same
| approach might be used for critical issues.
|
|
|
|
|
| --
| Do not spin this aircraft. If the aircraft does enter a
spin it will return to earth without further attention on
the part of the aeronaut.
|
| (first handbook issued with the Curtis-Wright flyer)

[Al]

"Gary Drescher" > wrote in message
. ..
> "Jose" > wrote in message
> .net...
>>> circumstances that really can cause a tail stall (such as [...] a
>>> too-forward CG).
>>
>> Ding.
>>
>> Obvious once I thought about it (duh!), but it had never occured to me
>> before, and nobody had ever mentioned it in my training. How far further
>> forward would the CG need to be to cause a tail stall in normal flight
>> attitudes?
>
> Although I haven't done the calculation, I'd be surprised if a typical GA
> plane could tail-stall at a normal in-flight angle of attack no matter how
> far forward you had the CG (unless you were to tie some cinder blocks to
> the nose gear or something). The danger would come during the landing
> flare, or if you tried to do slow flight or stall practice, or if
> turbulence were to abruptly increase the AoA.
>
> --Gary
>
>

I think I've had a tail stall. It was in a Robertson STOL, TU206, landing
under calm conditions, alone in the a/c with less than half fuel. I was
going for the ultimate slow landing when the aircraft pitched smartly
forward. I was maybe 2 feet off the ground, and the nose gear stopped the
rotation. I've tried to duplicate this at altitude, but never succeeded. I
was very forward CG, and the elevator was on the stops.

Al G.

[Jim Macklin]

;-)


"Al" > wrote in message
...
|
| "Gary Drescher" > wrote in message
| . ..
| > "Jose" > wrote in message
| >
.net...
| >>> circumstances that really can cause a tail stall (such
as [...] a
| >>> too-forward CG).
| >>
| >> Ding.
| >>
| >> Obvious once I thought about it (duh!), but it had
never occured to me
| >> before, and nobody had ever mentioned it in my
training. How far further
| >> forward would the CG need to be to cause a tail stall
in normal flight
| >> attitudes?
| >
| > Although I haven't done the calculation, I'd be
surprised if a typical GA
| > plane could tail-stall at a normal in-flight angle of
attack no matter how
| > far forward you had the CG (unless you were to tie some
cinder blocks to
| > the nose gear or something). The danger would come
during the landing
| > flare, or if you tried to do slow flight or stall
practice, or if
| > turbulence were to abruptly increase the AoA.
| >
| > --Gary
| >
| >
|
| I think I've had a tail stall. It was in a Robertson STOL,
TU206, landing
| under calm conditions, alone in the a/c with less than
half fuel. I was
| going for the ultimate slow landing when the aircraft
pitched smartly
| forward. I was maybe 2 feet off the ground, and the nose
gear stopped the
| rotation. I've tried to duplicate this at altitude, but
never succeeded. I
| was very forward CG, and the elevator was on the stops.
|
| Al G.
|
|
|

[Jim Macklin]

That's fine. I just like to have fun with words and
politics is always fun.


"T o d d P a t t i s t" > wrote
in message
...
| "Jim Macklin" >
wrote:
|
| >Are you talking about the Iraq war and the war on terror?
|
| No, and I'm not trying to make a personal attack on you
| either.
| --
| Do not spin this aircraft. If the aircraft does enter a
spin it will return to earth without further attention on
the part of the aeronaut.
|
| (first handbook issued with the Curtis-Wright flyer)

[Roger]

On 20 Jun 2006 03:30:46 -0700, wrote:

>Is it possible for an aircraft to stall and sink nose-up tail-down
>instead of pitching nose-down?

I'm assuming you mean *either* power on or off in which case:
Yes and without going into a deep stall and staying within the CG
limits.

>Or does aircraft design inherently
>preclude that? :)

Typically the design makes it either easy to get out of such an
attitude ,or makes it difficult to achieve.


If you try, you can stall a Bonanza, a 150, 172, or a Cherokee 180
and keep the nose up. The nose will not necessiaril fall through
until you release or at least ease off on the back pressure.

I can put the Deb into a stall, nose high and end up with a rather
high sink rate (phenomenal compared to a 150). The hard part is not
keeping the nose high, tail low, but keeping it right side up.


Roger Halstead (K8RI & ARRL life member)
(N833R, S# CD-2 Worlds oldest Debonair)
www.rogerhalstead.com
>
>Thanks in advance,
>
>Ramapriya

[Roger]

On Tue, 20 Jun 2006 12:18:27 -0500, "Jim Macklin"
> wrote:

>No, I said the buffet comes from the wing root, but the
>actual stall is when the tail stalls and looses lift (down
>force) and then the nose pitches down because the still
>flying wing CP is behind the CG.
>
>http://www.faa.gov/library/manuals/aviation/pilot_handbook/media/faa-h-8083-25-1of4.pdf

If the tail stalls there will be no question that the tail stalled. It
is not the same as a normal stall we have all experienced. It is
abrupt and it had better either happen with enough altitude to recover
(hopefully with the capability to recover) from a very steep nose down
attitude, or close enough to the ground that you don't brake anything
when the nose gear drops.

Back in the 50's and 60's there were some T-tailed aircraft that were
noted for the tail stalling if you tried to do a full stall landing.
That was a situation easily handled by not doing full stall landings
in those planes.

Another point about tail stalls. Ever wonder why a plane loaded with
ice comes down final at near cruise? You might stall the wing from
weight, or ice changing the configuration or the tail due to
configuration. When you look out there and discover the boots have
created a void behind the ice and are doing nothing to that 3 or more
inches of horn shaped ice on the leading edge you are now a test pilot
flying an airplane with unknown characteristics.

Roger Halstead (K8RI & ARRL life member)
(N833R, S# CD-2 Worlds oldest Debonair)
www.rogerhalstead.com

[[email protected]]

There's also the "smoke theory" of electricity. In reality there's no such
thing as electricity. What's going through the wires is smoke. This can be
proved in that when smoke gets out, electric devices stop working. When a
whole lot of smoke gets out, a whole lot of electric devices will stop
working.
On an unrelated topic, there's also no such thing as a light bulb. In
reality, it's a "darkness sucker". This can be proved in that when it
quits working, if you look at the bulb it will be very dark inside. This
is because the bulb is completely full of dark and can't hold any more.
Scott Wilson

[Jim Macklin]

There is no gravity either, the world just sucks.



> wrote in message
...
| There's also the "smoke theory" of electricity. In
reality there's no such
| thing as electricity. What's going through the wires is
smoke. This can be
| proved in that when smoke gets out, electric devices stop
working. When a
| whole lot of smoke gets out, a whole lot of electric
devices will stop
| working.
| On an unrelated topic, there's also no such thing as a
light bulb. In
| reality, it's a "darkness sucker". This can be proved in
that when it
| quits working, if you look at the bulb it will be very
dark inside. This
| is because the bulb is completely full of dark and can't
hold any more.
| Scott Wilson

[Roy Smith]

In article <h1cpg.52394$ZW3.19956@dukeread04>,
"Jim Macklin" > wrote:

> There is no gravity either, the world just sucks.

I assume you're familiar with the theory of quantum bogodynamics?

[Jim Macklin]

I maybe, but not sure about the spelling and pronunciation.
Is that bow God ynamics? or is it something else?


"Roy Smith" > wrote in message
...
| In article <h1cpg.52394$ZW3.19956@dukeread04>,
| "Jim Macklin" >
wrote:
|
| > There is no gravity either, the world just sucks.
|
| I assume you're familiar with the theory of quantum
bogodynamics?

[Jose[_1_]]

> I maybe, but not sure about the spelling and pronunciation.
> Is that bow God ynamics?

Bo Go Dynamics

Jose
--
The monkey turns the crank and thinks he's making the music.
for Email, make the obvious change in the address.