Newbie Qs on stalls and spins

[Ramapriya]

I've seen that John Denker in his article advocating pilots to keep
practicing recoveries from stalls and spins at a safe altitude...
which prompts me to ask the following:

1. Since I don't think I've experienced a stall or spin before, is it
a nice sensation to experience as a passenger, or wouldn't one be able
to tell?

2. Is it ok for pilots to practice stalls and spins on commercial
passenger aircraft in mid-flight? I ask, since I don't think it's
happened on any flight I've flown so far - unless some pilot did it
without informing the passengers :\

Ramapriya

[Bushy]

"Ramapriya" > wrote in message
m...
> I've seen that John Denker in his article advocating pilots to keep
> practicing recoveries from stalls and spins at a safe altitude...
> which prompts me to ask the following:
>
> 1. Since I don't think I've experienced a stall or spin before, is it
> a nice sensation to experience as a passenger, or wouldn't one be able
> to tell?

You know why they put those bags in the seat pocket of EVERY seat? It's for
the spins!

A stall can be gentle or a rough ride. It can also be the start of a spin.

> 2. Is it ok for pilots to practice stalls and spins on commercial
> passenger aircraft in mid-flight? I ask, since I don't think it's
> happened on any flight I've flown so far - unless some pilot did it
> without informing the passengers :\

Now I know what all that screaming and yelling coming from the back seats
the last time I went flying was! And why none of the hostees came forward
for a quickie!

> Ramapriya
>

;<)
Peter

[Bob Gardner]

Transport category aircraft (what you call commercial) are stalled during
manufacturer's certification tests and that is about it. Jet aircraft are
equipped with warning "stick shakers" that activate when the airplane is
even close to stalling, and "stick pullers" that take the decision out of
the pilot's hands by physically reducing the angle of attack whether the
pilot likes it or not. You will never experience a stall in a "commercial"
aircraft.

Bob Gardner
"Ramapriya" > wrote in message
m...
> I've seen that John Denker in his article advocating pilots to keep
> practicing recoveries from stalls and spins at a safe altitude...
> which prompts me to ask the following:
>
> 1. Since I don't think I've experienced a stall or spin before, is it
> a nice sensation to experience as a passenger, or wouldn't one be able
> to tell?
>
> 2. Is it ok for pilots to practice stalls and spins on commercial
> passenger aircraft in mid-flight? I ask, since I don't think it's
> happened on any flight I've flown so far - unless some pilot did it
> without informing the passengers :\
>
> Ramapriya
>

[Bob Gardner]

Sorry...the stick PUSHER reduces the angle of attack...the stick PULLER is
for overspeeds.

Bob Gardner

"Ramapriya" > wrote in message
m...
> I've seen that John Denker in his article advocating pilots to keep
> practicing recoveries from stalls and spins at a safe altitude...
> which prompts me to ask the following:
>
> 1. Since I don't think I've experienced a stall or spin before, is it
> a nice sensation to experience as a passenger, or wouldn't one be able
> to tell?
>
> 2. Is it ok for pilots to practice stalls and spins on commercial
> passenger aircraft in mid-flight? I ask, since I don't think it's
> happened on any flight I've flown so far - unless some pilot did it
> without informing the passengers :\
>
> Ramapriya
>

[Andrew Sarangan]

Bob, Is that true for landing also? Do they do full stall landings or do
they fly the airplane into the ground?



"Bob Gardner" > wrote in
:

> Transport category aircraft (what you call commercial) are stalled
> during manufacturer's certification tests and that is about it. Jet
> aircraft are equipped with warning "stick shakers" that activate when
> the airplane is even close to stalling, and "stick pullers" that take
> the decision out of the pilot's hands by physically reducing the angle
> of attack whether the pilot likes it or not. You will never experience
> a stall in a "commercial" aircraft.
>
> Bob Gardner
> "Ramapriya" > wrote in message
> m...
>> I've seen that John Denker in his article advocating pilots to keep
>> practicing recoveries from stalls and spins at a safe altitude...
>> which prompts me to ask the following:
>>
>> 1. Since I don't think I've experienced a stall or spin before, is it
>> a nice sensation to experience as a passenger, or wouldn't one be
>> able to tell?
>>
>> 2. Is it ok for pilots to practice stalls and spins on commercial
>> passenger aircraft in mid-flight? I ask, since I don't think it's
>> happened on any flight I've flown so far - unless some pilot did it
>> without informing the passengers :\
>>
>> Ramapriya
>>
>
>


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[Andrew Sarangan]

Every landing involves a stall. But that is not the same as a stall during
flight because you don't fall more than a few inches. You would not want to
do stalls with passengers in midflight unless you have talked about this
with your passenger. Spins are more dramatic, and I don't think it would be
wise to do them even if you have talked about it with your passenger.
Besides, spins are aerobatic maneuvers and you are required to have
parachutes unless you are doing it as part of a certificate or rating.


(Ramapriya) wrote in news:30a8759c.0411160734.89e24d5
@posting.google.com:

> I've seen that John Denker in his article advocating pilots to keep
> practicing recoveries from stalls and spins at a safe altitude...
> which prompts me to ask the following:
>
> 1. Since I don't think I've experienced a stall or spin before, is it
> a nice sensation to experience as a passenger, or wouldn't one be able
> to tell?
>
> 2. Is it ok for pilots to practice stalls and spins on commercial
> passenger aircraft in mid-flight? I ask, since I don't think it's
> happened on any flight I've flown so far - unless some pilot did it
> without informing the passengers :\
>
> Ramapriya
>


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[Peter Duniho]

"Andrew Sarangan" > wrote in message
7...
> Every landing involves a stall.

No, not every landing does. In fact, preferably few do.

> But that is not the same as a stall during
> flight because you don't fall more than a few inches.

IMHO, it is generally poor technique to "fall" at all during a landing. One
exception is a short field landing where minimum airspeed is the highest
priority, even if it means a "firm" landing. There may be other exceptions,
but otherwise the landing should be a smooth, controlled descent with the
airplane still flying when the tires touch the pavement and vertical speed
as close to zero as possible.

Pete

[Morgans]

"Ramapriya" > wrote

> 1. Since I don't think I've experienced a stall or spin before, is it
> a nice sensation to experience as a passenger, or wouldn't one be able
> to tell?

A stall might be felt as very unusual for a passenger, but unless the
passenger knew about flying, he/she might not know *what* happened.

Definitly would know *something* just happened. <g>
>
> 2. Is it ok for pilots to practice stalls and spins on commercial
> passenger aircraft in mid-flight?

Commercial flights are in the buisness of getting their customers where they
are going, as comfortably as possible. They do low bank angles, low G's,
and gentle climbs/descents. (except on initial departure, to get high enoug
for reasons of getting the noise away from the people on the ground) Stalls
and spins are not gentle.

I ask, since I don't think it's
> happened on any flight I've flown so far - unless some pilot did it
> without informing the passengers :\
>
> Ramapriya

Airline pilots do their training for such things, and emergency trainings
(engine out, unusual attitudes, and more) in simulators, and some (or most)
in full motion simulators, that tilt around to give the sensation of these
thing really happening. One reason they do this, is that it is too
expensive to do it in a plane that is empty, and not earning money, plus the
fact that the plane crashing, because the event was not dealt with very
well, would be, well, very bad. :-)
--
Jim in NC


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[Bob Moore]

"Bob Gardner" wrote

> Transport category aircraft (what you call commercial) are stalled
> during manufacturer's certification tests and that is about it.

Bob, in order to demonstrate my ability as an airline B-707 flight
instructor, the FAA required me to demonstrate instruction in full
stalls. Done lots of them. A little more exciting than a C-172,
but not much. :-) Instruction in "Dutch Roll" recovery with the
yaw damper turned off was much more exciting.

Bob Moore

[Ramapriya]

"Bob Gardner" > wrote in message >...
> Transport category aircraft (what you call commercial) are stalled during manufacturer's certification tests and that is about it. You will never experience a stall in a "commercial" aircraft.
>
> Bob Gardner

Oh, so the ones that become transport aircraft pilots don't ever get
to practice stall and spin recoveries, then? That'd make me more
jittery before going on a plane the next time...

I do remember reading (on planecrashinfo.com) CVR transcripts of the
final moments of a few plane crashes and recall that a couple of them
stalled prior to crashing. It's quite possible that the stall
condition was reached because of some other earlier error/malfunction
during the crash phase, but could it also be that the stall wasn't
recovered due to a lack of practice??

Ramapriya

[G.R. Patterson III]

Andrew Sarangan wrote:
>
> Every landing involves a stall.

Almost all of my landings do not involve a stall. The aircraft is flown onto the
ground in a three-point attitude just above the stall. That's if I do it right.

In the last couple of years I owned my 150, none of my landings in that plane
involved a stall.

George Patterson
If a man gets into a fight 3,000 miles away from home, he *had* to have
been looking for it.

[Andrew Sarangan]

I have to respectfully disagree. A short field landing is where you
plonk the airplane on the runway while it still has some flying speed.
If the airplane is slow enough, the landing impact will absorb enough
energy to prevent a bounce back into the air. On a normal landing, it is
quite possible to squeeze out every bit of excess airspeed in the flare.
When the airplane starts to descend despite the pilot's attempts is what
we normally consider as the onset of stall. Perhaps the word 'fall' is a
bit too strong for this situation because you are not falling more than
a few inches. If you are only inches above the runway, the vertical
speed will be virtually zero, and the touchdown should be smooth.
However, it is quite possible to land an airplane in flying speed as you
described as long as it is not too fast. I believe in this case you are
using the energy dissipation due to the touchdown to prevent the
airplane from bouncing back.




"Peter Duniho" > wrote in
:

> "Andrew Sarangan" > wrote in message
> 7...
>> Every landing involves a stall.
>
> No, not every landing does. In fact, preferably few do.
>
>> But that is not the same as a stall during
>> flight because you don't fall more than a few inches.
>
> IMHO, it is generally poor technique to "fall" at all during a
> landing. One exception is a short field landing where minimum
> airspeed is the highest priority, even if it means a "firm" landing.
> There may be other exceptions, but otherwise the landing should be a
> smooth, controlled descent with the airplane still flying when the
> tires touch the pavement and vertical speed as close to zero as
> possible.
>
> Pete
>
>
>


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[G.R. Patterson III]

Peter Duniho wrote:
>
> IMHO, it is generally poor technique to "fall" at all during a landing. One
> exception is a short field landing where minimum airspeed is the highest
> priority, even if it means a "firm" landing.

And, even with a short field landing, my aircraft is not stalled when flown
properly. I am likely to have a high enough descent rate for it to be a "firm"
landing; however, if I time the last burst of throttle correctly, even that
won't be the case.

George Patterson
If a man gets into a fight 3,000 miles away from home, he *had* to have
been looking for it.

[Bob Moore]

(Ramapriya) wrote
> but could it also be that the stall wasn't
> recovered due to a lack of practice??

No...airline pilots practice stall recovery in the
simulators at least twice-a-year.

Bob Moore, CFI
ATP B-707 B-727
PanAm (retired)

[Newps]

G.R. Patterson III wrote:

>
> Peter Duniho wrote:
>
>>IMHO, it is generally poor technique to "fall" at all during a landing. One
>>exception is a short field landing where minimum airspeed is the highest
>>priority, even if it means a "firm" landing.
>
>
> And, even with a short field landing, my aircraft is not stalled when flown
> properly. I am likely to have a high enough descent rate for it to be a "firm"
> landing; however, if I time the last burst of throttle correctly, even that
> won't be the case.

When I want to wedge my 182 into a short space I fly the plane at about
45 mph indicated on very short final and land like a Navy pilot. No
real flare, just hold attitude and smash into the ground. Not enough
energy to bounce back in the air. Brakes semi-locked, pull the power,
stopped in 400 feet.

[Rich Lemert]

Bob Gardner wrote:

> You will never experience a stall in a "commercial"
> aircraft.

I wouldn't be too complacent about this. There were some articles
about the American crash in New York shortly after 9/11 that were
discussing why the rudder had apparently torn off of the aircraft.
At least one of those articles discussed another incident involving
the same type of plane, in which the stress of the incident _almost_
tore off it's rudder. No one paid much attention to the fact at the
time, though, because they were more concerned with figuring out why
the pilots had allowed the plane to stall.

Rich Lemert

[Jay Beckman]

"Newps" > wrote in message
...
>
>
> G.R. Patterson III wrote:
>
>>
>> Peter Duniho wrote:
>>
>>>IMHO, it is generally poor technique to "fall" at all during a landing.
>>>One
>>>exception is a short field landing where minimum airspeed is the highest
>>>priority, even if it means a "firm" landing.
>>
>>
>> And, even with a short field landing, my aircraft is not stalled when
>> flown
>> properly. I am likely to have a high enough descent rate for it to be a
>> "firm"
>> landing; however, if I time the last burst of throttle correctly, even
>> that
>> won't be the case.
>
> When I want to wedge my 182 into a short space I fly the plane at about 45
> mph indicated on very short final and land like a Navy pilot. No real
> flare, just hold attitude and smash into the ground. Not enough energy to
> bounce back in the air. Brakes semi-locked, pull the power, stopped in
> 400 feet.

When I got my first taste of short field landings, I was too fast and too
flat which left me floating beyond the target.

I finally turned to my CFI and said..."Should I just be trying to catch a
"three wire?""

"EUREEKA!!!"

I pictured what an F/A18 looks like on short final and saw myself trapping
aboard the "USS Coolidge Muni" and nailed the next three just past the
runway end lights.

Used the same mental imagery on my checkride and planted that F-172 right on
the second runway centerline stripe...right where the DPE wanted it!

Jay Beckman
KCHD
PP-ASEL
Still nowhere to go but up!

[Hilton]

Andrew Sarangan wrote:
> Every landing involves a stall.

Nope.


> Besides, spins are aerobatic maneuvers and you are required to have
> parachutes unless you are doing it as part of a certificate or rating.

Nope - you don't need to be "doing it as part of a certificate or rating".

Hilton

[Morgans]

Besides, spins are aerobatic maneuvers and you are required to have
> > parachutes unless you are doing it as part of a certificate or rating.
>
> Nope - you don't need to be "doing it as part of a certificate or rating".
>
> Hilton
>
Cites please?
--
Jim in NC


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[Peter Duniho]

"Andrew Sarangan" > wrote in message
7...
>
> I have to respectfully disagree. A short field landing is where you
> plonk the airplane on the runway while it still has some flying speed.

Sorry...weren't you the guy who just today posted "every landing involves a
stall"?

Usenet's going to be just that much less fun if you picking apart your *own*
posts. :)

Anyway, to each their own regarding technique. However, with a nice steep
approach and low airspeed, you can have both minimum flying speed (or even a
stall), and still have a rapid flare with no float. It's all about keeping
your approach speed sufficiently slow.

Yes, if you fly your approach at 1.3 Vs0, a full stall landing will mean a
nice long float. But that's not the correct airspeed for a short field
landing.

Anyway, I take it you now agree with what was my main point: that it's NOT
true that "every landing involves a stall". Thank you for your cooperation.
:)

Pete

[Stefan]

Ramapriya wrote:

> Oh, so the ones that become transport aircraft pilots don't ever get
> to practice stall and spin recoveries, then? That'd make me more
> jittery before going on a plane the next time...

I think most of them train stalls in the simulator on a regular basis.
Spins however... I might be wrong, but to my knowledge, most transport
category airplanes would break on spin recovery.

Stefan

[John Galban]

"Morgans" > wrote in message >...
> Besides, spins are aerobatic maneuvers and you are required to have
> > > parachutes unless you are doing it as part of a certificate or rating.
> >
> > Nope - you don't need to be "doing it as part of a certificate or rating".
> >
> > Hilton
> >
> Cites please?

I believe he's referring to 91.307(c). It says :

(c) Unless each occupant of the aircraft is wearing an approved
parachute, no pilot of a civil aircraft carrying any person (other
than a crewmember) may execute any intentional maneuver that exceeds—

(1) A bank of 60 degrees relative to the horizon; or

(2) A nose-up or nose-down attitude of 30 degrees relative to the
horizon.

"C" basically restricts the rule to pilots of aircraft that are
carrying persons other than crewmembers. So, I can go out and spin my
Cherokee solo, but if I'm carrying a passenger, we both require
chutes. Then there is another exception :

(d) Paragraph (c) of this section does not apply to—

(1) Flight tests for pilot certification or rating; or

(2) Spins and other flight maneuvers required by the regulations for
any certificate or rating when given by—

(i) A certificated flight instructor; or

(ii) An airline transport pilot instructing in accordance with §61.67
of this chapter.

So, the parachute rule also does not apply if I'm doing a flight
test, or if I'm performing spins or other maneuvers required for any
certificate or rating, as long as there's an instructor. It doesn't
say that I have to be in training for a particular rating. The (2)
part of the rule excepts the type of manuevers, it doesn't require
that you be training for a specific rating.

This rule allows an instructor to demonstrate a spin to a PPL
student without requiring that they wear parachutes. Even though
there is no spin training required in the PPL, the maneuver itself is
allowed because it is "required by the regulations for any certificate
or rating".

To me (not being a CFI), this means that I can spin my Cherokee
without chutes either solo, or with an instructor, but if the person
in the next seat is not an instructor or ATP, chutes are required.

John Galban=====>N4BQ (PA28-180)

[Gary Drescher]

"John Galban" > wrote in message
m...
> To me (not being a CFI), this means that I can spin my Cherokee
> without chutes either solo, or with an instructor,

Are there Cherokees that permit intentional spins? The Arrow and Warrior
POHs prohibit them.

--Gary

[David CL Francis]

On Tue, 16 Nov 2004 at 09:43:22 in message
>, Bob Gardner >
wrote:

>You will never experience a stall in a "commercial"
>aircraft.

If you do you may not survive it.

Ref: Air Disaster Volume 3 by Macarthur Job
April 26. 1994 A300 Airbus flying from Yaipei to Nagoya in Japan.

On approach to land in clear conditions at night and fully configured
for landing it passed the outer marker. But 3nm from touch down it
briefly levelled off. Descent continued but at decreasing speed and nose
up pitch increased. At 1nm and 500ft to go engine power was increased,
then after a brief interval cut again.

Several seconds later power was increased again and it nosed up into a
steep climb. The crew called 'Going around' but the climb increase
sharply. It climber steeper and steeper with the speed falling and after
gaining 1500ft it stalled. The nose came up a bit after the stall but it
struck the ground very hard. Only 7 passengers survived out of 256.

It is easy to write the above bare facts, what happened required a lot
of pages to explain. It depended on not recognising what was happening,
misunderstanding whether or not the autopilot was engaged and a
misunderstanding of how the aircraft would respond with the autopilot
engaged. Except in Land and Go Around mode the auto pilot disconnects
when force is applied to the control column. In those modes the
autopilot reacts by changing the tail plane trim to cancel the crew
input. It seems the Go Around Lever may have been accidentally engaged.


--
David CL Francis

[Andrew Sarangan]

OK OK... What I meant was, every normal landing (other than short field
techniques) would involve a stall. I guess I have to be more careful in
my choice of words :-)



"Peter Duniho" > wrote in
:

> "Andrew Sarangan" > wrote in message
> 7...
>>
>> I have to respectfully disagree. A short field landing is where you
>> plonk the airplane on the runway while it still has some flying
>> speed.
>
> Sorry...weren't you the guy who just today posted "every landing
> involves a stall"?
>
> Usenet's going to be just that much less fun if you picking apart your
> *own* posts. :)
>
> Anyway, to each their own regarding technique. However, with a nice
> steep approach and low airspeed, you can have both minimum flying
> speed (or even a stall), and still have a rapid flare with no float.
> It's all about keeping your approach speed sufficiently slow.
>
> Yes, if you fly your approach at 1.3 Vs0, a full stall landing will
> mean a nice long float. But that's not the correct airspeed for a
> short field landing.
>
> Anyway, I take it you now agree with what was my main point: that it's
> NOT true that "every landing involves a stall". Thank you for your
> cooperation.
>:)
>
> Pete
>
>

[Morgans]

"John Galban" > wrote

> To me (not being a CFI), this means that I can spin my Cherokee
> without chutes either solo, or with an instructor, but if the person
> in the next seat is not an instructor or ATP, chutes are required.
>
> John Galban=====>N4BQ (PA28-180)

So CFI's get to do stuff that we can not do without them. With no chutes,
CFI's and students, and others all splat the same. Just a comment.
--
Jim in NC


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[G.R. Patterson III]

Andrew Sarangan wrote:
>
> OK OK... What I meant was, every normal landing (other than short field
> techniques) would involve a stall. I guess I have to be more careful in
> my choice of words :-)

No, you have to take another look at it. NO normal landing involves a stall.

George Patterson
If a man gets into a fight 3,000 miles away from home, he *had* to have
been looking for it.

[Peter Duniho]

"Andrew Sarangan" > wrote in message
1...
> OK OK... What I meant was, every normal landing (other than short field
> techniques) would involve a stall.

See George's post. Your modified statement is still incorrect.

[Bill Denton]

Well, from what I understand, the generally accepted aviation definition of
a "stall" is when a lifting portion of the aircraft is no longer lifting.

Given that, if the lifting parts never stalled the aircraft would never stop
flying.




"G.R. Patterson III" > wrote in message
...
>
>
> Andrew Sarangan wrote:
> >
> > OK OK... What I meant was, every normal landing (other than short field
> > techniques) would involve a stall. I guess I have to be more careful in
> > my choice of words :-)
>
> No, you have to take another look at it. NO normal landing involves a
stall.
>
> George Patterson
> If a man gets into a fight 3,000 miles away from home, he *had* to
have
> been looking for it.

[John Galban]

"Gary Drescher" > wrote in message >...
>
> Are there Cherokees that permit intentional spins? The Arrow and Warrior
> POHs prohibit them.
>

Yes. It depends on the year and equipment configuration. Most
-140s are approved for intentional spins in the Utility category.
Many early body (pre '73) Cherokee -180s were also approved for
intentional spins in the Utility category. In '73 the -180 fuselage
was stretched 5 inches, which moved the C.G. back and intentional
spins were no longer approved. The Archer and Warrior both use the
longer fuselage and are not approved.

Note : There are some exceptions for -140 and -180 models equipped
with the large fresh air blower in the tail. You should check the
paperwork and placards on an individual airplane to determine if it is
approved. Also, the PA28 is very sensitive to C.G. in a spin. W&B
MUST be in the Utility category.

John Galban=====>N4BQ (PA28-180)

[Terry Bolands]

"Peter Duniho" > wrote in message >...

> See George's post. Your modified statement is still incorrect.

Wow, thanks for adding so much to the conversation.

[G.R. Patterson III]

Bill Denton wrote:
>
> Well, from what I understand, the generally accepted aviation definition of
> a "stall" is when a lifting portion of the aircraft is no longer lifting.

No, the definition of an aerodynamic stall is when the airflow passing over the
upper surface of the wing separates from it and produces a burble. Lift is
certainly reduced when this occurs, but the absence of lift by itself is not the
definition of a stall.

George Patterson
If a man gets into a fight 3,000 miles away from home, he *had* to have
been looking for it.

[Peter Duniho]

"Terry Bolands" > wrote in message
om...
> Wow, thanks for adding so much to the conversation.

You're welcome, and thank YOU very much for the same.

At least I have *some* posts in this thread with actual content. Too bad
you can't say the same.

[Michael]

"Morgans" > wrote
> So CFI's get to do stuff that we can not do without them. With no chutes,
> CFI's and students, and others all splat the same. Just a comment.

And a valid one. CFI's are presumed to have a high level of skill and
judgment, and thus it is assumed that an adequate level of safety will
be maintained even without parachutes.

The presumption is wrong. Holding a CFI ticket only proves an ability
to jump through some FAA hoops. Because of this, spin training
accidents killed more people than inadvertent spins back when spin
training was required for all pilots. The solution SHOULD have been a
higher level of spin qualification for CFI's, both so the accidents in
training would not happen and so the people teaching spins actually
knew what they were teaching. The solution WAS to stop requiring spin
training.

Michael

[Rutger]

(John Galban) wrote in message >...
> "Gary Drescher" > wrote in message >...
> >
> > Are there Cherokees that permit intentional spins? The Arrow and Warrior
> > POHs prohibit them.
> >
>
> Yes. It depends on the year and equipment configuration. Most
> -140s are approved for intentional spins in the Utility category.

Please have a look at what the FAA officially says about spinning a
Cherokee. Specifically the 140 model.

http://www.faa.gov/certification/aircraft/av-info/ad/saibs/ACE-97-02.htm

I took my spin training in a Cherokee 140 and we had a difficult time
keeping it held in a spin, simply letting up a little on the rudder
pedal would exit the spin. We were probably a little too low on the
weight and forward on the CG to get a clearly defined spin going, and
neither I nor my instructor had the balls to want to try "aggravating"
the spin with ailerons or added power. Simply letting go of all the
controls and the little plane would straighten up and begin flying
again, but the airspeed does climb quite disturbingly briskly when the
nose is pointed straight down and the wing starts flying again.
Recovering out of the dive frightened me more than the spin itself.
Reading the FAA's SAIB at the URL above, seems to suggest that a 140
can wrap up in a really tight and scary rapid spin, but we were only
able to to get a really mushy, slow spin going. And before anyone
flames me about it, yes we both were wearing chutes and we looked and
felt really dorky wearing the "acro chutes" in a Cherokee. In
retrospect, if something had gone so badly wrong that we would have
needed the chutes, we probably both could not have been able to egress
a tumbling, plummeting Cherokee thru it's single door anyway.

[Cub Driver]

>OK OK... What I meant was, every normal landing (other than short field
>techniques) would involve a stall. I guess I have to be more careful in
>my choice of words :-)

I was really astonished, the first time I landed as a passenger in a
small plane, to be told by the pilot that the horn that blared just
before touchdown was a stall warning. I assumed the pilot had made a
mistake (in his landing technique, not in his explanation for the
horn)!

all the best -- Dan Ford
email: (put Cubdriver in subject line)

Warbird's Forum www.warbirdforum.com
Piper Cub Forum www.pipercubforum.com
the blog www.danford.net

[Cub Driver]

On 17 Nov 2004 12:12:55 -0800, (John Galban)
wrote:

>(2) Spins and other flight maneuvers required by the regulations for
>any certificate or rating when given by—
>
>(i) A certificated flight instructor; or

So ... the instructor who spun the Cub with me in the back was in
violation of the FARs? The maneuver was required for my certificate!

all the best -- Dan Ford
email: (put Cubdriver in subject line)

Warbird's Forum www.warbirdforum.com
Piper Cub Forum www.pipercubforum.com
the blog www.danford.net

[Morgans]

"Cub Driver" > wrote

> I was really astonished, the first time I landed as a passenger in a
> small plane, to be told by the pilot that the horn that blared just
> before touchdown was a stall warning. I assumed the pilot had made a
> mistake (in his landing technique, not in his explanation for the
> horn)!
>
> all the best -- Dan Ford
> email: (put Cubdriver in subject line)

But remember, stall horns are usually 8 mph before stall.
--
Jim in NC


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[David CL Francis]

On Thu, 18 Nov 2004 at 09:26:27 in message
>, Bill Denton >
wrote:

>Given that, if the lifting parts never stalled the aircraft would never stop
>flying.

Airliners do not land like that. They fly gently on to the runway and
then the lift is killed by lowering the nose. The lift is reduced but
the angle of attack for a stall is not reached.
--
David CL Francis

[Andrew Sarangan]

You guys are challenging my understanding of landings :-)

The landing technique, as taught by many before us, is to
progressively increase elevator deflection to maintain zero vertical
speed. I suppose it is possible that you can reach max elevator
without reaching critical AOA. But I think that is unlikely, because
that would mean you will never be able to perform power-off stalls in
level unaccelerated flight.



"Peter Duniho" > wrote in message >...
> "Andrew Sarangan" > wrote in message
> 1...
> > OK OK... What I meant was, every normal landing (other than short field
> > techniques) would involve a stall.
>
> See George's post. Your modified statement is still incorrect.

[Newps]

Andrew Sarangan wrote:

> You guys are challenging my understanding of landings :-)
>
> The landing technique, as taught by many before us, is to
> progressively increase elevator deflection to maintain zero vertical
> speed. I suppose it is possible that you can reach max elevator
> without reaching critical AOA.

Ah, yeah. See Cessna 177A. They had to add slots to the stab so the
tail wouldn't stall before the wing.

[ShawnD2112]

"Morgans" > wrote in message
...
>
> "Cub Driver" > wrote
>
>> I was really astonished, the first time I landed as a passenger in a
>> small plane, to be told by the pilot that the horn that blared just
>> before touchdown was a stall warning. I assumed the pilot had made a
>> mistake (in his landing technique, not in his explanation for the
>> horn)!
>>
>> all the best -- Dan Ford
>> email: (put Cubdriver in subject line)
>
> But remember, stall horns are usually 8 mph before stall.
> --
> Jim in NC
>
Careful, Jim. Depends on your flight regime. The stall horn is actually
set a couple of DEGREES above stall angle of attack. In the landing
configuration that may equate to about 8 mph, but that's not how it's set.

Shawn
> Outgoing mail is certified Virus Free.
> Checked by AVG anti-virus system (http://www.grisoft.com).
> Version: 6.0.797 / Virus Database: 541 - Release Date: 11/16/2004
>
>

[Peter Duniho]

"Andrew Sarangan" > wrote in message
om...
> You guys are challenging my understanding of landings :-)

Challenge is good for the soul. :)

> The landing technique, as taught by many before us, is to
> progressively increase elevator deflection to maintain zero vertical
> speed.

That's the ideal. In practice, it's nearly impossible to obtain exactly
zero vertical speed, and it's bad form for your vertical speed to go
positive (i.e. start to climb). In a properly executed landing, vertical
speed is always negative (i.e. a descent), and one typically reaches the
runway before reaching the critical AOA.

> I suppose it is possible that you can reach max elevator
> without reaching critical AOA.

Certainly once the main gear is on the ground, it is. I commonly continue
to increase elevator back pressure after touchdown, so as to allow the
nosewheel to touchdown gently, and may well reach max elevator travel before
allowing the nosewheel to touch. But this is a red herring in any case, as
there is no requirement nor even a recommendation to reach max elevator
travel during a landing.

> But I think that is unlikely, because
> that would mean you will never be able to perform power-off stalls in
> level unaccelerated flight.

At least one plane does have this characteristic (Ercoupe). Landings in
that airplane, one in which it is impossible to stall (in level
unaccelerated flight, anyway, such as one would experience during a
landing), are pretty much just like landings in any other airplane.

A typical "normal" landing involves flying a slightly fast approach speed
(1.2 to 1.3 Vs0), and then flaring and touching down while still above Vs0.
One hopes that during the flare, airspeed is reduced to as close to Vs0 as
possible so as to minimize touchdown speed. In optimal conditions, a
well-executed landing will even be done with the stall warning going off.
But touchdown itself should still occur prior to the stall occurring (which,
of course, prevents the stall from occurring at all).

Bottom line: just as George said, "no normal landing involves a stall".

Pete

[Bill Denton]

But if an airfoil has two states, stalled or flying, how can you land
without a stall?



"Todd Pattist" > wrote in message
...
> Peter's comments on this are right on.
>
> I'll add a bit to the difference between a landing and a
> "level" stall in flight. As you may recall, the total drag
> on an aircraft is the sum of induced drag and parasitic
> drag. The induced drag is high at low speeds and parasitic
> is high at high speeds.
>
> Anyway, as you slow in your attempt to produce a level
> stall, induced drag rises very quickly (by a factor
> proportional to one over the airspeed squared.) This rapid
> drag rise causes a descent that quickly increases the angle
> of attack of the wing to above the critical angle and thus
> you quickly get to the stall and beyond it., producing a
> loss of lift and the continuation of the descent.
>
> During landing, the increased induced drag tries to cause
> the same descent you experienced aloft, but fortunately your
> wheels are there to catch you, and you never get the rapid
> AOA increase that you got aloft, so you never get a true
> stall.
>
> >"Andrew Sarangan" > wrote in message
> om...
> >> You guys are challenging my understanding of landings :-)
> >
> >Challenge is good for the soul. :)
> >
> >> The landing technique, as taught by many before us, is to
> >> progressively increase elevator deflection to maintain zero vertical
> >> speed.
> >
> >That's the ideal. In practice, it's nearly impossible to obtain exactly
> >zero vertical speed, and it's bad form for your vertical speed to go
> >positive (i.e. start to climb). In a properly executed landing, vertical
> >speed is always negative (i.e. a descent), and one typically reaches the
> >runway before reaching the critical AOA.
> >
> >> I suppose it is possible that you can reach max elevator
> >> without reaching critical AOA.
> >
> >Certainly once the main gear is on the ground, it is. I commonly
continue
> >to increase elevator back pressure after touchdown, so as to allow the
> >nosewheel to touchdown gently, and may well reach max elevator travel
before
> >allowing the nosewheel to touch. But this is a red herring in any case,
as
> >there is no requirement nor even a recommendation to reach max elevator
> >travel during a landing.
> >
> >> But I think that is unlikely, because
> >> that would mean you will never be able to perform power-off stalls in
> >> level unaccelerated flight.
> >
> >At least one plane does have this characteristic (Ercoupe). Landings in
> >that airplane, one in which it is impossible to stall (in level
> >unaccelerated flight, anyway, such as one would experience during a
> >landing), are pretty much just like landings in any other airplane.
> >
> >A typical "normal" landing involves flying a slightly fast approach speed
> >(1.2 to 1.3 Vs0), and then flaring and touching down while still above
Vs0.
> >One hopes that during the flare, airspeed is reduced to as close to Vs0
as
> >possible so as to minimize touchdown speed. In optimal conditions, a
> >well-executed landing will even be done with the stall warning going off.
> >But touchdown itself should still occur prior to the stall occurring
(which,
> >of course, prevents the stall from occurring at all).
> >
> >Bottom line: just as George said, "no normal landing involves a stall".
> >
> >Pete
> >
>
> "It is possible to fly without motors, but not without knowledge and
skill."
> Wilbur Wright

[John Galban]

Cub Driver > wrote in message >...
> On 17 Nov 2004 12:12:55 -0800, (John Galban)
> wrote:
>
> >(2) Spins and other flight maneuvers required by the regulations for
> >any certificate or rating when given by?
> >
> >(i) A certificated flight instructor; or
>
> So ... the instructor who spun the Cub with me in the back was in
> violation of the FARs? The maneuver was required for my certificate!
>

I don't see how. What I posted above is an exception to the
parachute requirement. If he was a CFI, I don't see how he could have
been in violation of the regs, regardless of whether or not you were
wearing chutes.

John Galban=====>N4BQ (PA28-180)

[Morgans]

"ShawnD2112" > wrote > >
> Careful, Jim. Depends on your flight regime. The stall horn is actually
> set a couple of DEGREES above stall angle of attack. In the landing
> configuration that may equate to about 8 mph, but that's not how it's set.
>
> Shawn

True, but you can NEVER make a statement that does not have any exceptions.
:-)
--
Jim in NC


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[Bill Denton]

No, not a trick question...

You CAN'T take off without a stall, if an airfoil only has two states:
flying or stalled.

If the airfoil is flying you cannot take off, and if it's not flying it's
stalled.

(There's a whole bunch of physics involved here that I don't yet know, so
anyone, please feel free to correct whatever I get wrong.)

You stated: "It's flying as soon as you start moving on the runway". That is
not correct. It doesn't begin to fly until you develop enough relative wind
to create enough lift to overcome drag. If an airplane is only moving at 1
kt. down a runway, it is probably not flying.

Forward motion of the aircraft is not required. Given a strong enough
headwind, an airplane will readily fly backward; just ask some J3 drivers.

And an aircraft will not land until it has reached a "stalled" state.




"Todd Pattist" > wrote in message
...
> "Bill Denton" > wrote:
>
> >But if an airfoil has two states, stalled or flying, how can you land
> >without a stall?
>
> Is this a trick question? For the same reason you can take
> off without a stall. It's flying as soon as you start
> moving on the runway and it's flying while you're in the air
> and it does the same thing in reverse on landing.
> "It is possible to fly without motors, but not without knowledge and
skill."
> Wilbur Wright

[Bob Moore]

"Morgans" wrote
> But remember, stall horns are usually 8 mph before stall.

Section 23.207: Stall warning.

(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.

[Peter Duniho]

"Bill Denton" > wrote in message
...
> You CAN'T take off without a stall, if an airfoil only has two states:
> flying or stalled.

First of all, there is a continuous regime of "flight" between stalled and
not stalled. It's not binary. But secondly, even if you assume the airfoil
has just the two states, the rest of your conclusion regarding that is
incorrect...

> If the airfoil is flying you cannot take off, and if it's not flying it's
> stalled.

"If the airfoil is flying you cannot take off". Care to rephrase that? At
best, I can assume you meant to write "if the airfoil is not flying you
cannot take off". Which would be true (inasumuch as I might assume what you
mean by "flying"), but not particularly germane. Your second clause, "if
it's not flying it's stalled" seems to get to the heart of your
misunderstanding however.

"Flying" is not a technical aerodynamic term, and in particular you cannot
say that "flying" is the opposite of "stalled". The opposite of "stalled"
is "not stalled".

As has already been pointed out, "stall" simply means that the airfoil's
angle of attack is greater than the critical angle of attack. An airfoil
that has no relative wind has NO angle of attack, and the term "stall" is
meaningless in that context. Once the airfoil has relative wind (e.g. you
start your takeoff roll), you can then look at the angle of attack and
compare it to the critical angle of attack. Looking at the example of a
takeoff roll, the wing's angle of attack remains below (and generally, WELL
below) the critical angle of attack at all times.

No stall at any point in time during the takeoff roll.

Same thing applies to most landings. As the airplane slows after touching
down, the amount of lift being generated is reduced, but this is compensated
for by the wheels providing the balance of the required support. At no
point does the wing wind up with a higher angle of attack than the critical
angle of attack, and thus there is no stall.

> (There's a whole bunch of physics involved here that I don't yet know, so
> anyone, please feel free to correct whatever I get wrong.)

We're trying. :)

> You stated: "It's flying as soon as you start moving on the runway". That
> is
> not correct.

It IS correct. Well, inasmuch as you've failed to define "flying" for us,
and inasmuch as "flying" has no predefined aerodynamic definition. The
instant there is ANY relative wind, the wing is creating lift (since its
angle of attack is below the critical AOA). That's my definition of
"flying": "creating lift". What's your definition?

> It doesn't begin to fly until you develop enough relative wind
> to create enough lift to overcome drag.

Lift overcomes gravity. Thrust overcomes drag. In order to lift off from
the ground, you do need enough relative wind to allow the wing to generate
enough lift to overcome the force of gravity. But if by "flying" you simply
mean "to have lifted off from the ground", then it's especially true that
"flying" is in no way the opposite of "stalled".

> If an airplane is only moving at 1
> kt. down a runway, it is probably not flying.

Again, you'll have to define "flying". But the wing certainly is developing
lift, and certainly is NOT stalled.

> Forward motion of the aircraft is not required. Given a strong enough
> headwind, an airplane will readily fly backward; just ask some J3 drivers.

Forward motion through the air mass IS required. Given a strong enough
headwind, an airplane may well depart from the ground, but as soon as it's
no longer tied to the ground, it will slow relative to the airmass and fall
back to the ground. Probably in a stalled state, even.

> And an aircraft will not land until it has reached a "stalled" state.

Simply untrue. Virtually all of my landings involve touching down and
coming to a stop without ever exceeding the wing's critical AOA. I hesitate
to claim that I've *never* stalled the wing during a landing, but I sure
don't do it intentionally.

Pete

[Andrew Sarangan]

Todd Pattist > wrote in
:

> "Bill Denton" > wrote:
>
>>But if an airfoil has two states, stalled or flying, how can you land
>>without a stall?
>
> Is this a trick question? For the same reason you can take
> off without a stall. It's flying as soon as you start
> moving on the runway and it's flying while you're in the air
> and it does the same thing in reverse on landing.
> "It is possible to fly without motors, but not without knowledge and
> skill." Wilbur Wright


That is the best explanation I have seen. Thanks!

[Blanche]

Reference: "Flight Theory for Pilots", Charles Dole, 4th ed.

stall -- airflow separation of the boundary layer from a lifting surface.
characterized by a loss of life and an increase in drag. two types of
stall of interest tot he non-jet pilot: slow speed and accelerated.

[jls]

"Blanche" > wrote in message
...
> Reference: "Flight Theory for Pilots", Charles Dole, 4th ed.
>
> stall -- airflow separation of the boundary layer from a lifting surface.
> characterized by a loss of life and an increase in drag. two types of
> stall of interest tot he non-jet pilot: slow speed and accelerated.
>

Proofread you work or you might scare hell out of somebody.

[Bill Denton]

Thank you for your response. A lot of this has to do with semantics and
poorly defined terms on both sides...my comments are in the text:


"Peter Duniho" > wrote in message
...
> "Bill Denton" > wrote in message
> ...
> > You CAN'T take off without a stall, if an airfoil only has two states:
> > flying or stalled.
>
> First of all, there is a continuous regime of "flight" between stalled and
> not stalled. It's not binary. But secondly, even if you assume the
airfoil
> has just the two states, the rest of your conclusion regarding that is
> incorrect...

You are both right and wrong on this one. Obviously, different parts of an
aircraft stall at different speeds. This is why a stall in most light
aircraft is generally benign: the stabilizer continues to fly long after the
wing has stalled, resulting in the pitch-down generally required for stall
recovery. So, as you approach the stall speed for an AIRCRAFT, differrent
parts of the airplane will be stalled, or not flying; other parts will still
be flying.

Obviously, there is a range between the point where an element is producing
zero lift, where it is producing enough lift to "fly" the unit itself at a
consistent altitude, and where it is produing enough lift to fly the
required load at a consistent altitude.

Assume a perfect set of conditons, primarily containing an absolutely
"level" portion of the earth, and consider the following scenarios.

You take an airplane to 1,000 ft AGL, and trim it so it is flying perfectly
straight and level. You then close the throttle slightly, resulting in a
slight descent. Even thought you are still flying straight and level,
eventually you will impact the earth, even though the airplane as a whole
(and probably all of it's component parts) are still "flying".

You then take an airplane to 1,000 ft AGL, and trim it so it is flying
perfectly straight and level, but this time you completely close the
throttle. In a short time, the wings will stop producing enough lift to keep
the airplane in flight, it will pitch down and impact the earth, even though
some of the airplane's component parts may still be flying.

It is this second condition that most people consider to be a stall.

But since my terminology may not be correct, it is obvious that I am neither
an aeronautical engineer, a physisist, or as yet a pilot (none of which I
claim to be), I think it is also evident that I do understand at least the
basic principles involved in the discussion.


>
> > If the airfoil is flying you cannot take off, and if it's not flying
it's
> > stalled.
>
> "If the airfoil is flying you cannot take off". Care to rephrase that?
At
> best, I can assume you meant to write "if the airfoil is not flying you
> cannot take off". Which would be true (inasumuch as I might assume what
you
> mean by "flying"), but not particularly germane. Your second clause, "if
> it's not flying it's stalled" seems to get to the heart of your
> misunderstanding however.

This is a matter of the original poster's lack of precision, and my own
desire to have a little fun. From the rest of the post, it is obvious that
the poster is referring to a larger element than an airfoil, perhaps a wing
or an entire airplane. Had I written the original post I would have used
airplane.

But please assume an airplane, accept my terminology, and consider the
following:

If a wheel is rolling, you cannot start it rolling.

My statement was: " If the airfoil is flying you cannot take off, and if
it's not flying it's stalled", which would translate as follows: "If the
airplane IS flying it cannot START flying"' the rest reflects the
flying/stalled paradyme, which I readly admit is not absolutely correct.


>
> "Flying" is not a technical aerodynamic term, and in particular you cannot
> say that "flying" is the opposite of "stalled". The opposite of "stalled"
> is "not stalled".
>
> As has already been pointed out, "stall" simply means that the airfoil's
> angle of attack is greater than the critical angle of attack. An airfoil
> that has no relative wind has NO angle of attack, and the term "stall" is
> meaningless in that context. Once the airfoil has relative wind (e.g. you
> start your takeoff roll), you can then look at the angle of attack and
> compare it to the critical angle of attack. Looking at the example of a
> takeoff roll, the wing's angle of attack remains below (and generally,
WELL
> below) the critical angle of attack at all times.
>
> No stall at any point in time during the takeoff roll.
>
> Same thing applies to most landings. As the airplane slows after touching
> down, the amount of lift being generated is reduced, but this is
compensated
> for by the wheels providing the balance of the required support. At no
> point does the wing wind up with a higher angle of attack than the
critical
> angle of attack, and thus there is no stall.
>
> > (There's a whole bunch of physics involved here that I don't yet know,
so
> > anyone, please feel free to correct whatever I get wrong.)
>
> We're trying. :)
>
> > You stated: "It's flying as soon as you start moving on the runway".
That
> > is
> > not correct.
>
> It IS correct. Well, inasmuch as you've failed to define "flying" for us,
> and inasmuch as "flying" has no predefined aerodynamic definition. The
> instant there is ANY relative wind, the wing is creating lift (since its
> angle of attack is below the critical AOA). That's my definition of
> "flying": "creating lift". What's your definition?

Actually, it was the original poster who failed to define "flying" and
specify what was flying. As noted above, I am looking at this in the context
of an entire airplane, which seems to have been the original poster's
intent. In fact, the airplane doesn't need to move on the runway at all;
given a sufficient releative wind, parts of the airplane would begin to fly
without the airplane moving forward at all. And given a relative wind even
slightly higher than the stall speed of the aircraft, it could theoretically
take off and continue to ascend with no forward movement.

I agree with your definition, but it has to be consiered in light of whether
we are discussing a single element or an entire airplane.


>
> > It doesn't begin to fly until you develop enough relative wind
> > to create enough lift to overcome drag.
>
> Lift overcomes gravity. Thrust overcomes drag. In order to lift off from
> the ground, you do need enough relative wind to allow the wing to generate
> enough lift to overcome the force of gravity. But if by "flying" you
simply
> mean "to have lifted off from the ground", then it's especially true that
> "flying" is in no way the opposite of "stalled".

You are correct on the lift/thrust thing; please understand that it's been
25 years since I read the Jepp private pilot manual ;-)


>
> > If an airplane is only moving at 1
> > kt. down a runway, it is probably not flying.
>
> Again, you'll have to define "flying". But the wing certainly is
developing
> lift, and certainly is NOT stalled.

How 'bout if I throw in a 10 kt tailwind? <g>


>
> > Forward motion of the aircraft is not required. Given a strong enough
> > headwind, an airplane will readily fly backward; just ask some J3
drivers.
>
> Forward motion through the air mass IS required. Given a strong enough
> headwind, an airplane may well depart from the ground, but as soon as it's
> no longer tied to the ground, it will slow relative to the airmass and
fall
> back to the ground. Probably in a stalled state, even.

I proabably should have qualified that, but remember I'm not writing a
textbook, I think all of us here frequently accept some unstated
assumptions.


>
> > And an aircraft will not land until it has reached a "stalled" state.
>
> Simply untrue. Virtually all of my landings involve touching down and
> coming to a stop without ever exceeding the wing's critical AOA. I
hesitate
> to claim that I've *never* stalled the wing during a landing, but I sure
> don't do it intentionally.

And this comes back to the flying/stalled paradym.


BTW: I generally pick up a "nugget" or two from your posts, so your work is
not in vain. I appreaciate it.

>
> Pete
>
>

[G.R. Patterson III]

Bill Denton wrote:
>
> But if an airfoil has two states, stalled or flying, how can you land
> without a stall?

It doesn't have just two states. It can be moving too slowly to be flying
without being stalled. As has been posted several times, it is not stalled
unless the airflow over the upper surface of the wing has separated from it. As
has also been posted, that will not happen without an excessive angle of attack.

George Patterson
If a man gets into a fight 3,000 miles away from home, he *had* to have
been looking for it.

[Bob Moore]

"Bill Denton" wrote
> You take an airplane to 1,000 ft AGL, and trim it so it is flying
> perfectly straight and level. You then close the throttle slightly,
> resulting in a slight descent. Even thought you are still flying
> straight and level, eventually you will impact the earth, even though
> the airplane as a whole (and probably all of it's component parts) are
> still "flying".

No Bill..."straight and level" means maintaining heading and altitude

> You then take an airplane to 1,000 ft AGL, and trim it so it is flying
> perfectly straight and level, but this time you completely close the
> throttle. In a short time, the wings will stop producing enough lift
> to keep the airplane in flight, it will pitch down and impact the
> earth, even though some of the airplane's component parts may still be
> flying.

No Bill...in this case, the aircraft will pitch down to maintain the
trimmed airspeed and the airplane WILL NOT stall. Yes, it will descend
until it impacts the ground, but at no time will the aircraft stall.

> It is this second condition that most people consider to be a stall.

No Bill...it is called a glide

> But since my terminology may not be correct,

Boy...you hit that nail on the head

> it is obvious that I am neither an aeronautical engineer, a physisist,
> or as yet a pilot

Yes Bill...that is absolutely obvious

> I think it is also evident that I do understand at least the basic
> principles involved in the discussion.

No Bill... you do not.

Bob Moore
ATP B-707 B-727 L-188
Flight Instructor Airplanes and Instruments (since 1970)
Naval Aviator S-2F P-2V P-3B !958-1967
PanAm (retired)

[G.R. Patterson III]

Bill Denton wrote:
>
> You are both right and wrong on this one. Obviously, different parts of an
> aircraft stall at different speeds. This is why a stall in most light
> aircraft is generally benign: the stabilizer continues to fly long after the
> wing has stalled, resulting in the pitch-down generally required for stall
> recovery.

You're correct that the stabilizer may stall at a different point than the wing,
but the stabilizer on a traditional (ie. non-canard) aircraft pushes down on the
tail, not up. If it stalls before the wing, the nose falls because there's
nothing hold the tail down. If the wing stalls first, the nose falls because
there's nothing holding the nose up.

George Patterson
If a man gets into a fight 3,000 miles away from home, he *had* to have
been looking for it.

[Peter Duniho]

"Bill Denton" > wrote in message
...
> You are both right and wrong on this one.

No. I am entirely right, not wrong at all.

> Obviously, different parts of an aircraft stall at different speeds.

This is true, but completely irrelevant to my statement.

> [...]
> You then take an airplane to 1,000 ft AGL, and trim it so it is flying
> perfectly straight and level, but this time you completely close the
> throttle. In a short time, the wings will stop producing enough lift to
> keep
> the airplane in flight, it will pitch down and impact the earth, even
> though
> some of the airplane's component parts may still be flying.

First, your scenario is completely incorrect as to what would happen if you
brought the throttle to idle. The airplane would NOT stall. It would
simply pitch down enough to maintain the trimmed airspeed, and glide to
whatever final destination it was aimed at.

But more importantly, your understanding of a stall is flawed. Even simply
looking at just the wing, and even ignoring such design features as washout,
upon reaching the critical angle of attack lift does not go straight from
maximum available lift to 0. There is a very narrow range of angle of
attack where the lift drops off rapidly, and within this range, there is
just as much lift as was available at angles of attack just below the
critical angle of attack.

For a variety of reasons, it's unlikely that a pilot would ever successfully
negotiate this very narrow range. But it does exist, and a person who
claims that a wing is strictly "not stalled" or "stalled" is simply
demonstrated lack of completely knowledge of what happens during a stall. A
stall is more like a dimmer light switch (with a very short throw) than it
is like a regular "on/off" light switch.

> [...] I think it is also evident that I do understand at least the
> basic principles involved in the discussion.

Very basic principles. But you still have quite a ways to go. You might do
well to stop telling people they are wrong, at least until you've actually
*mastered* the subject.

> But please assume an airplane, accept my terminology, and consider the
> following:
>
> If a wheel is rolling, you cannot start it rolling.
>
> My statement was: " If the airfoil is flying you cannot take off, and if
> it's not flying it's stalled", which would translate as follows: "If the
> airplane IS flying it cannot START flying"' the rest reflects the
> flying/stalled paradyme, which I readly admit is not absolutely correct.

So you really did mean to write "if the airfoil is flying you cannot take
off". I've got to say, that's got to be one of the most intentionally
obtuse ways of saying something I've seen in a long time.

In any case, you are simply incorrect to say "if it's not flying it's
stalled". That is a patently false proposition. I have an airplane sitting
in my hangar right now that is not flying (at least, it had better not be!),
but it is not stalled either.

> Actually, it was the original poster who failed to define "flying" and
> specify what was flying. As noted above, I am looking at this in the
> context
> of an entire airplane, which seems to have been the original poster's
> intent.

Another red herring. It really doesn't matter whether you are talking about
the entire airplane or the wing. But for the record, when one refers to a
"stall", they are generally referring to a stall of the main wing (and by
implication, the entire airplane).

> In fact, the airplane doesn't need to move on the runway at all;
> given a sufficient releative wind, parts of the airplane would begin to
> fly
> without the airplane moving forward at all.

I thought your claim was that an airplane that was flying (and thus
presumably parts of an airplane that are flying) cannot take off. Now you
are saying parts of the airplane can fly while still on the ground. Your
statements are inconsistent with each other.

> And given a relative wind even
> slightly higher than the stall speed of the aircraft, it could
> theoretically
> take off and continue to ascend with no forward movement.

No, it could not. With a strong enough wind, the airplane might lift off
the ground, but it would immediately begin to slow within the airmass
(accelerating backwards relative to the ground) and descend back to the
ground. There would be no "continue to ascend" about it.

> I agree with your definition, but it has to be consiered in light of
> whether
> we are discussing a single element or an entire airplane.

We are discussing the wing, which is the only thing of interest in this
case. If you want to call that "the entire airplane", that's fine too, but
make no mistake: it's still just the wing.

>> > If an airplane is only moving at 1
>> > kt. down a runway, it is probably not flying.
>>
>> Again, you'll have to define "flying". But the wing certainly is
> developing
>> lift, and certainly is NOT stalled.
>
> How 'bout if I throw in a 10 kt tailwind? <g>

If you want to change the discussion in an attempt to make your comments
make sense, feel free. I probably won't have the patience to bother though,
and will simply feel justified in assuming that you aren't really interested
in learning what the facts are.

I recommend you stick with the original ideas, and where you've clearly
meant "1 knot of relative wind" by saying "if an airplane is only moving at
1 knot down a runway", you should avoid complicating things by trying to
reinterpret what you've written.

>> Simply untrue. Virtually all of my landings involve touching down and
>> coming to a stop without ever exceeding the wing's critical AOA. I
> hesitate
>> to claim that I've *never* stalled the wing during a landing, but I sure
>> don't do it intentionally.
>
> And this comes back to the flying/stalled paradym.

The word is "paradigm". And frankly, I have no idea what you mean by "this
comes back to". This thread *should* have stayed with the question of a
stall all along. Only your digressions have prevented that.

The bottom line here is that your statements that "you can't take off
without a stall" and that "an aircraft will not land until it has reached a
stalled state" are both patently false. You can very much both take off and
land without ever stalling the airplane.

Pete

[Bill Denton]

Let's assume that I am completely wrong. Wouldn't we all have been better
served had you provided correct information as opposed to simply pointing
out my error. I can't learn anything from that.

Given your credentials, could you not have provided me, and many others,
some useful information?


"Bob Moore" > wrote in message
. 121...
> "Bill Denton" wrote
> > You take an airplane to 1,000 ft AGL, and trim it so it is flying
> > perfectly straight and level. You then close the throttle slightly,
> > resulting in a slight descent. Even thought you are still flying
> > straight and level, eventually you will impact the earth, even though
> > the airplane as a whole (and probably all of it's component parts) are
> > still "flying".
>
> No Bill..."straight and level" means maintaining heading and altitude
>
> > You then take an airplane to 1,000 ft AGL, and trim it so it is flying
> > perfectly straight and level, but this time you completely close the
> > throttle. In a short time, the wings will stop producing enough lift
> > to keep the airplane in flight, it will pitch down and impact the
> > earth, even though some of the airplane's component parts may still be
> > flying.
>
> No Bill...in this case, the aircraft will pitch down to maintain the
> trimmed airspeed and the airplane WILL NOT stall. Yes, it will descend
> until it impacts the ground, but at no time will the aircraft stall.
>
> > It is this second condition that most people consider to be a stall.
>
> No Bill...it is called a glide
>
> > But since my terminology may not be correct,
>
> Boy...you hit that nail on the head
>
> > it is obvious that I am neither an aeronautical engineer, a physisist,
> > or as yet a pilot
>
> Yes Bill...that is absolutely obvious
>
> > I think it is also evident that I do understand at least the basic
> > principles involved in the discussion.
>
> No Bill... you do not.
>
> Bob Moore
> ATP B-707 B-727 L-188
> Flight Instructor Airplanes and Instruments (since 1970)
> Naval Aviator S-2F P-2V P-3B !958-1967
> PanAm (retired)

[David CL Francis]

On Fri, 19 Nov 2004 at 16:21:11 in message
>, Bill Denton >
wrote:
>No, not a trick question...
>
>You CAN'T take off without a stall, if an airfoil only has two states:
>flying or stalled.
>
If you admit you have only a limited knowledge why start off with a
categorical statement? This indicates that you do not yet understand
what an airfoil stall is. A stall occurs when the angle of attack of an
airfoil exceeds a limit beyond which lift falls rather than increases.
This angle would not normally ever be exceed in a take off. [1]

>If the airfoil is flying you cannot take off, and if it's not flying it's
>stalled.
>
I suppose you mean above that if an aircraft is already flying it must
have already taken off! Certain amount of truth in that but your second
phrase is definitely wrong. See [1]

>(There's a whole bunch of physics involved here that I don't yet know, so
>anyone, please feel free to correct whatever I get wrong.)
>
Fine but the purchase of an elementary book on aerodynamics would be a
good start. You cannot expect a complete course on elementary
aerodynamics by asking questions which to me, sound as if you are not
really seeking elucidation.

>You stated: "It's flying as soon as you start moving on the runway". That is
>not correct. It doesn't begin to fly until you develop enough relative wind
>to create enough lift to overcome drag. If an airplane is only moving at 1
>kt. down a runway, it is probably not flying.
>

While 'it's flying as soon as you start moving on the runway' is not an
ideal way of putting it the rest of your paragraph suggests that you do
not yet understand the difference between lift and drag. Your third
sentence is another categorical statement which is also wrong.

Lift is a force generated at right angles to the airflow and drag is a
force along the direction of the airflow. Since they act at right angles
to each other lift is not a force that 'overcomes drag'. Your fourth
sentence is correct when you talk about the whole aircraft but not if
you are just talking about an airfoil..
>
>And an aircraft will not land until it has reached a "stalled" state.

Thus misconception of either or both of 'landing and stall' has already
been dealt with in this thread.
--
David CL Francis

[Bill Denton]

Follow on...

My examples failed because I didn't properly think them through, and
consequently did not account for pitch. Here is what I should have written,
with my corrections in all caps...

You take an airplane to 1,000 ft AGL, and trim it so it is flying perfectly
straight and level. You then close the throttle slightly, resulting in a
slight descent. IF PITCH TRIM IS NOT CHANGED, eventually you will impact the
earth, even though the airplane as a whole (and probably all of it's
component parts) are still "flying".

You then take an airplane to 1,000 ft AGL, and trim it so it is flying
perfectly straight and level, but this time you completely close the
throttle WHILE ATTEMPTING TO MAINTAIN THE ORIGINAL PITCH. In a short time,
the wings will stop producing enough lift to keep the airplane in flight, it
will pitch down and impact the earth, even though some of the airplane's
component parts may still be flying.

I believe these scenarios are correct, and I promise to do better next time!
<g>

[Bill Denton]

My comments in text...




"Peter Duniho" > wrote in message
...
> "Bill Denton" > wrote in message
> ...
> > You are both right and wrong on this one.
>
> No. I am entirely right, not wrong at all.
>
> > Obviously, different parts of an aircraft stall at different speeds.
>
> This is true, but completely irrelevant to my statement.
>
> > [...]
> > You then take an airplane to 1,000 ft AGL, and trim it so it is flying
> > perfectly straight and level, but this time you completely close the
> > throttle. In a short time, the wings will stop producing enough lift to
> > keep
> > the airplane in flight, it will pitch down and impact the earth, even
> > though
> > some of the airplane's component parts may still be flying.
>
> First, your scenario is completely incorrect as to what would happen if
you
> brought the throttle to idle. The airplane would NOT stall. It would
> simply pitch down enough to maintain the trimmed airspeed, and glide to
> whatever final destination it was aimed at.

Both scenarios are incorrect as originally posted. Please see my second
respone to Bob Moore (just above) for my corrections.


>
> But more importantly, your understanding of a stall is flawed. Even
simply
> looking at just the wing, and even ignoring such design features as
washout,
> upon reaching the critical angle of attack lift does not go straight from
> maximum available lift to 0. There is a very narrow range of angle of
> attack where the lift drops off rapidly, and within this range, there is
> just as much lift as was available at angles of attack just below the
> critical angle of attack.
>
> For a variety of reasons, it's unlikely that a pilot would ever
successfully
> negotiate this very narrow range. But it does exist, and a person who
> claims that a wing is strictly "not stalled" or "stalled" is simply
> demonstrated lack of completely knowledge of what happens during a stall.
A
> stall is more like a dimmer light switch (with a very short throw) than it
> is like a regular "on/off" light switch.

From my previous post: "Obviously, there is a range between the point where
an element is producing zero lift, where it is producing enough lift to
"fly" the unit itself at a consistent altitude, and where it is produing
enough lift to fly the required load at a consistent altitude."

The inverse would also be true.

Generally, I am using the term "stall" to indicate a state where the object
is producing zero lift, and "flying" to indicate that some lift is being
produced. However, I sometimes use flying to indicate that the object is
generating enough lift to raise itself and it's load above the earth. I will
try to be more consistent and clear in the future.

I don't claim that this is absolutely, or in any way correct, but this is
how I am using the terms.


>
> > [...] I think it is also evident that I do understand at least the
> > basic principles involved in the discussion.
>
> Very basic principles. But you still have quite a ways to go. You might
do
> well to stop telling people they are wrong, at least until you've actually
> *mastered* the subject.
>
> > But please assume an airplane, accept my terminology, and consider the
> > following:
> >
> > If a wheel is rolling, you cannot start it rolling.
> >
> > My statement was: " If the airfoil is flying you cannot take off, and if
> > it's not flying it's stalled", which would translate as follows: "If the
> > airplane IS flying it cannot START flying"' the rest reflects the
> > flying/stalled paradyme, which I readly admit is not absolutely correct.
>
> So you really did mean to write "if the airfoil is flying you cannot take
> off". I've got to say, that's got to be one of the most intentionally
> obtuse ways of saying something I've seen in a long time.

That is what I mean to write, but again I was not writing from scratch; I
was picking up on the orignal poster.


>
> In any case, you are simply incorrect to say "if it's not flying it's
> stalled". That is a patently false proposition. I have an airplane
sitting
> in my hangar right now that is not flying (at least, it had better not
be!),
> but it is not stalled either.

No argument that I am probably using the terms incorrectly; please see my
previous note.

>
> > Actually, it was the original poster who failed to define "flying" and
> > specify what was flying. As noted above, I am looking at this in the
> > context
> > of an entire airplane, which seems to have been the original poster's
> > intent.
>
> Another red herring. It really doesn't matter whether you are talking
about
> the entire airplane or the wing. But for the record, when one refers to a
> "stall", they are generally referring to a stall of the main wing (and by
> implication, the entire airplane).

Which is the way I am generally using the term, unless I am specifically
referring to a stall affecting only a specific portion of an airplane.

>
> > In fact, the airplane doesn't need to move on the runway at all;
> > given a sufficient releative wind, parts of the airplane would begin to
> > fly
> > without the airplane moving forward at all.
>
> I thought your claim was that an airplane that was flying (and thus
> presumably parts of an airplane that are flying) cannot take off. Now you
> are saying parts of the airplane can fly while still on the ground. Your
> statements are inconsistent with each other.

That was what I stated, if the ENTIRE airplane is flying, i.e. with no parts
in contact with the earth, it cannot take off.

But with a tail dragger, doesn't the horizontal stabilizer begin to produce
enough lift to raise the tail, and raise the tailwheel above the earth,
before the wing produces enough lift to raise the entire airplane abouve the
earth?


>
> > And given a relative wind even
> > slightly higher than the stall speed of the aircraft, it could
> > theoretically
> > take off and continue to ascend with no forward movement.
>
> No, it could not. With a strong enough wind, the airplane might lift off
> the ground, but it would immediately begin to slow within the airmass
> (accelerating backwards relative to the ground) and descend back to the
> ground. There would be no "continue to ascend" about it.

"accelerating backwards relative to the ground" is not the same as "no
forward movement".

I was incorrect with "continue to ascend".

>
> > I agree with your definition, but it has to be consiered in light of
> > whether
> > we are discussing a single element or an entire airplane.
>
> We are discussing the wing, which is the only thing of interest in this
> case. If you want to call that "the entire airplane", that's fine too,
but
> make no mistake: it's still just the wing.

But just a wing in a wind tunnel behaves differently than the same wing when
attached to an airplane. And parts of an airplane other than the wing can
generate lift.


>
> >> > If an airplane is only moving at 1
> >> > kt. down a runway, it is probably not flying.
> >>
> >> Again, you'll have to define "flying". But the wing certainly is
> > developing
> >> lift, and certainly is NOT stalled.

I should have added "in a condition of zero wind". Given that, there are
probably wings out there that would not generate appreciable lift at 1 kt.


> >
> > How 'bout if I throw in a 10 kt tailwind? <g>
>
> If you want to change the discussion in an attempt to make your comments
> make sense, feel free. I probably won't have the patience to bother
though,
> and will simply feel justified in assuming that you aren't really
interested
> in learning what the facts are.
>
> I recommend you stick with the original ideas, and where you've clearly
> meant "1 knot of relative wind" by saying "if an airplane is only moving
at
> 1 knot down a runway", you should avoid complicating things by trying to
> reinterpret what you've written.

As I noted above, I failed to address relative wind and referred only to the
aircraft's speed.


>
> >> Simply untrue. Virtually all of my landings involve touching down and
> >> coming to a stop without ever exceeding the wing's critical AOA. I
> > hesitate
> >> to claim that I've *never* stalled the wing during a landing, but I
sure
> >> don't do it intentionally.
> >
> > And this comes back to the flying/stalled paradym.

Sometimes I rely too much on spell chekers.


>
> The word is "paradigm". And frankly, I have no idea what you mean by
"this
> comes back to". This thread *should* have stayed with the question of a
> stall all along. Only your digressions have prevented that.
>
> The bottom line here is that your statements that "you can't take off
> without a stall" and that "an aircraft will not land until it has reached
a
> stalled state" are both patently false. You can very much both take off
and
> land without ever stalling the airplane.

Again, that comes down to terminology; and I again state that I may well be
using it incorrectly.


>
> Pete
>
>

[Hilton]

Hi,

Hint to everyone involved in this thread: Don't use the word "flying" wrt
stalls etc - it is completely ambiguous. Use "exceeding the critical AOA",
"stalled", "producing lift", etc. It's hard enough discussing aerodynamics
on the NGs, why waste bandwidth trying to define ambiguous words?

Just my 5c.

Hilton

[G.R. Patterson III]

Bill Denton wrote:
>
> You then take an airplane to 1,000 ft AGL, and trim it so it is flying
> perfectly straight and level, but this time you completely close the
> throttle WHILE ATTEMPTING TO MAINTAIN THE ORIGINAL PITCH. In a short time,
> the wings will stop producing enough lift to keep the airplane in flight, it
> will pitch down and impact the earth, even though some of the airplane's
> component parts may still be flying.

Well, perhaps some might. If you maintain a level pitch attitude in my aircraft
with the throttle closed, the plane will simply descend. The airspeed will be
between 60 to 70 mph with 0 degrees of flaps (stall is about 55 in that
configuration). If you want mine to stall, you'll have to get the nose pretty
high.

Now, if I were to close the throttle and attempt to maintain *altitude* by
raising the nose, she'd stall. When that happens, the nose repeatedly drops a
bit and then goes back up, and the plane descends at a moderate rate of speed in
a nose high attitude.

George Patterson
If a man gets into a fight 3,000 miles away from home, he *had* to have
been looking for it.

[Peter Duniho]

"Bill Denton" > wrote in message
...
>
> [...]
> Generally, I am using the term "stall" to indicate a state where the
> object
> is producing zero lift,

As has been pointed out numerous times, this is not the correct definition
of "stall".

If you want to participate in discussions in this newsgroup on the topic of
a stall, you need to use the same definition the rest of us are using. It
is pointless to make up your own definition and then go around telling US
that WE are wrong, just because we're not using the same screwed up
definition of a word you're using.

> and "flying" to indicate that some lift is being
> produced.

No, that's not how you're using the term "flying". If it were, then you
would not claim that "If the airfoil is flying you cannot take off", because
by your NEW definition of "flying" (given above) the airfoil is indeed
flying long before takeoff.

It's bad enough you're making up your own non-standard definitions for words
that have reasonably well-accepted definitions in aviation (and in the case
of "stall", that has a very specific and well-understood definition). But
if you can't even be consistent about your OWN use of the made-up
definitions, it's basically impossible to carry on any sort of discussion.

> However, I sometimes use flying to indicate that the object is
> generating enough lift to raise itself and it's load above the earth. I
> will
> try to be more consistent and clear in the future.

Yes, please do. As I said, you simply compound your basic error (using the
wrong definition in the first place) with your error of inconsistency.

> I don't claim that this is absolutely, or in any way correct, but this is
> how I am using the terms.

It's good you don't claim the uses are correct, because they are not.

> [...]
>> I thought your claim was that an airplane that was flying (and thus
>> presumably parts of an airplane that are flying) cannot take off. Now
>> you
>> are saying parts of the airplane can fly while still on the ground. Your
>> statements are inconsistent with each other.
>
> That was what I stated, if the ENTIRE airplane is flying, i.e. with no
> parts
> in contact with the earth, it cannot take off.

Again, the main problem here appears to be your lack of any semblance of
consistency. By at least one definition of "flying" that you are using, it
would be impossible for just some of the components of the airplane to be
"flying". As I said, your statements are inconsistent with each other.

> But with a tail dragger, doesn't the horizontal stabilizer begin to
> produce
> enough lift to raise the tail, and raise the tailwheel above the earth,
> before the wing produces enough lift to raise the entire airplane abouve
> the
> earth?

Yes, generally. But so what?

>> > And given a relative wind even
>> > slightly higher than the stall speed of the aircraft, it could
>> > theoretically
>> > take off and continue to ascend with no forward movement.
>>
>> No, it could not. With a strong enough wind, the airplane might lift off
>> the ground, but it would immediately begin to slow within the airmass
>> (accelerating backwards relative to the ground) and descend back to the
>> ground. There would be no "continue to ascend" about it.
>
> "accelerating backwards relative to the ground" is not the same as "no
> forward movement".

No, it's not. So what?

> I was incorrect with "continue to ascend".

Yes, you were. That was the entire point of that part of my reply.

> But just a wing in a wind tunnel behaves differently than the same wing
> when
> attached to an airplane. And parts of an airplane other than the wing can
> generate lift.

So what? They don't contribute much, and in any case, they don't stall the
way the wing does. We are still only talking about the main wing stalling.
No matter how many times you try to redirect the conversation to some
mythical component-based analysis of the airplane, we are still just talking
about the wing, its angle of attack, and what happens if and when that angle
of attack exceeds the critical angle of attack for a stall.

>> >> > If an airplane is only moving at 1
>> >> > kt. down a runway, it is probably not flying.
>> >>
>> >> Again, you'll have to define "flying". But the wing certainly is
>> > developing
>> >> lift, and certainly is NOT stalled.
>
> I should have added "in a condition of zero wind". Given that, there are
> probably wings out there that would not generate appreciable lift at 1 kt.

Most wings would not generate very much lift at all at 1 knot of relative
wind. But they do generate lift (ALL of them), and they are NOT stalled.

> [...]
> Again, that comes down to terminology; and I again state that I may well
> be
> using it incorrectly.

Yes, you are. Utterly. This entire subthread is a direct result of that
incorrect use of the terminology, and your insistence on *correcting* those
of us who are using the CORRECT terminology.

Pete

[G.R. Patterson III]

Bill Denton wrote:
>
> Generally, I am using the term "stall" to indicate a state where the object
> is producing zero lift, and "flying" to indicate that some lift is being
> produced. However, I sometimes use flying to indicate that the object is
> generating enough lift to raise itself and it's load above the earth. I will
> try to be more consistent and clear in the future.
>
> I don't claim that this is absolutely, or in any way correct, but this is
> how I am using the terms.

That's certainly not the correct definition of a stall. See any good textbook (I
suggest Jeppesen-Sanderson's "Private Pilot Manual"). I agree with Hilton that
the term "flying" is ambiguous in the literature.

> But with a tail dragger, doesn't the horizontal stabilizer begin to produce
> enough lift to raise the tail, and raise the tailwheel above the earth,
> before the wing produces enough lift to raise the entire airplane abouve the
> earth?

Not really. The stabilizer on a conventional aircraft pushes down on the tail;
it produces reverse lift, if you like. The tail is usually raised on a
taildragger by forward elevator. There *is* a certain amount of lifting force
caused by the impact of air against the lower surface of the stabilizer, and
this *may* be sufficient to get the tail off the ground before the mains lift
off. If I'm trimmed for takeoff, however, and I simply neutralize the controls,
my taildragger will bring all three wheels off at about the same time. At an
uncomfortably low airspeed, I might add.

George Patterson
If a man gets into a fight 3,000 miles away from home, he *had* to have
been looking for it.

[Bill Denton]

I think it's time that I wake up on this beautiful Chicago day and realize
that I have once again spent more time talking than listening, with the
consequence that I have managed to talk my head completely up my ass. Which
generally leaves one talking out there ass! Unfortunately, I do that
sometimes.

I'm reasonably intelligent, logical, and creative, and often that allows me
to come up with some really good conclusions and solutions. But I sometimes
fail to remember that others may have gotten there and gotten it right long
before I even start down the road.

For those of you who have spent your time and energy trying to help me "get
right with God" on this subject, I truly appreciate your patience and help.
I will try to do more listening than talking in the future.

For those of you who long since gave up on me, I admit to sometimes being
the donkey in the parable about the donkey and the brick, and it sometimes
takes a few licks with a few bricks for me to get the picture.

For all of you who simply put up with my lack of knowledge; thank you.

For those of you who tried to help me and teach me something; thank you. I
will try to be more receptive in the future.

And to all of you, my sincerest apologies for being such a pain in the ass.




"Todd Pattist" > wrote in message
...
> Peter's comments on this are right on.
>
> I'll add a bit to the difference between a landing and a
> "level" stall in flight. As you may recall, the total drag
> on an aircraft is the sum of induced drag and parasitic
> drag. The induced drag is high at low speeds and parasitic
> is high at high speeds.
>
> Anyway, as you slow in your attempt to produce a level
> stall, induced drag rises very quickly (by a factor
> proportional to one over the airspeed squared.) This rapid
> drag rise causes a descent that quickly increases the angle
> of attack of the wing to above the critical angle and thus
> you quickly get to the stall and beyond it., producing a
> loss of lift and the continuation of the descent.
>
> During landing, the increased induced drag tries to cause
> the same descent you experienced aloft, but fortunately your
> wheels are there to catch you, and you never get the rapid
> AOA increase that you got aloft, so you never get a true
> stall.
>
> >"Andrew Sarangan" > wrote in message
> om...
> >> You guys are challenging my understanding of landings :-)
> >
> >Challenge is good for the soul. :)
> >
> >> The landing technique, as taught by many before us, is to
> >> progressively increase elevator deflection to maintain zero vertical
> >> speed.
> >
> >That's the ideal. In practice, it's nearly impossible to obtain exactly
> >zero vertical speed, and it's bad form for your vertical speed to go
> >positive (i.e. start to climb). In a properly executed landing, vertical
> >speed is always negative (i.e. a descent), and one typically reaches the
> >runway before reaching the critical AOA.
> >
> >> I suppose it is possible that you can reach max elevator
> >> without reaching critical AOA.
> >
> >Certainly once the main gear is on the ground, it is. I commonly
continue
> >to increase elevator back pressure after touchdown, so as to allow the
> >nosewheel to touchdown gently, and may well reach max elevator travel
before
> >allowing the nosewheel to touch. But this is a red herring in any case,
as
> >there is no requirement nor even a recommendation to reach max elevator
> >travel during a landing.
> >
> >> But I think that is unlikely, because
> >> that would mean you will never be able to perform power-off stalls in
> >> level unaccelerated flight.
> >
> >At least one plane does have this characteristic (Ercoupe). Landings in
> >that airplane, one in which it is impossible to stall (in level
> >unaccelerated flight, anyway, such as one would experience during a
> >landing), are pretty much just like landings in any other airplane.
> >
> >A typical "normal" landing involves flying a slightly fast approach speed
> >(1.2 to 1.3 Vs0), and then flaring and touching down while still above
Vs0.
> >One hopes that during the flare, airspeed is reduced to as close to Vs0
as
> >possible so as to minimize touchdown speed. In optimal conditions, a
> >well-executed landing will even be done with the stall warning going off.
> >But touchdown itself should still occur prior to the stall occurring
(which,
> >of course, prevents the stall from occurring at all).
> >
> >Bottom line: just as George said, "no normal landing involves a stall".
> >
> >Pete
> >
>
> "It is possible to fly without motors, but not without knowledge and
skill."
> Wilbur Wright

[[email protected]]

Bill,

You are so cool! Each of us should reflect upon our own participation
in rec.aviation.*, and once again become so humble as to thank your
mentors (and adversaries), and once again attempt to absorb the
incredible knowledge (often) portrayed here!

I, for one, am thankful for what I have learned here, and the little
that I am privileged to say about mountain flying.

Jer/ Eberhard

Bill Denton > wrote:
> For all of you who simply put up with my lack of knowledge; thank you.

> For those of you who tried to help me and teach me something; thank you. I
> will try to be more receptive in the future.

> And to all of you, my sincerest apologies for being such a pain in the ass.

Best regards,

Jer/ "Flight instruction and mountain flying are my vocation!" Eberhard

--
Jer/ (Slash) Eberhard, Mountain Flying Aviation, LTD, Ft Collins, CO
CELL 970 231-6325 EMAIL jer'at'frii.com WEB http://users.frii.com/jer/
C-206 N9513G, CFII Airplane&Glider, FAA-DEN Aviation Safety Counselor
CAP-CO Mission&Aircraft CheckPilot, BM218 HAM N0FZD, 221 Young Eagles!

[Rick Macklem]

Stefan > wrote in message >...
> Ramapriya wrote:
>
> > Oh, so the ones that become transport aircraft pilots don't ever get
> > to practice stall and spin recoveries, then? That'd make me more
> > jittery before going on a plane the next time...
>
> I think most of them train stalls in the simulator on a regular basis.
> Spins however... I might be wrong, but to my knowledge, most transport
> category airplanes would break on spin recovery.
>
> Stefan

There are now companies (www.fcitraining.com, www.stallion51.com to
name two
examples) that are trying
to market specialty training in unusual attitude recovery, using
aircraft capable of aerobatics. I don't know if any of the major
airlines have bought into this,
but I understand that some of the corporate flight departments have.

I will also note that just about any airline pilot has practiced stall
recovery
in light planes during their training and some have done spin training
in light
aircraft, as well.

Whether or not this is revelant to large aircraft operations
or not seems to be a "hot topic" these days and I, personally, have no
idea
what the answer is?

rick, who loves to loop and roll light aircraft but has no idea if
this
would be useful training for airline pilots

[mhquay]

Bill Denton wrote:
>
> Generally, I am using the term "stall" to indicate a state where the
object
> is producing zero lift, and "flying" to indicate that some lift is
being
> produced. However, I sometimes use flying to indicate that the object
is
> generating enough lift to raise itself and it's load above the earth.
I will
> try to be more consistent and clear in the future.
>
> I don't claim that this is absolutely, or in any way correct, but
this is
> how I am using the terms

Bill

Without getting too technical.

An aircraft is "flying" regardless of whether it is climbing, decending
or "flying" level.
By using the throttle and the attitude of the nose of the aircraft the
pilot controls the relative airflow over the wing and thus determines
the mode of flight he wants.

Climbing - Lift is Greater than weight
Level - Lift = weight
Descending (including landing) - Lift if less than weight

All the above are controlled "flying"

The stall is uncontrolled "flying" and the only time this should happen
whilst "flying" is in stall recovery practice, aerobatics and sometimes
a second prior to touchdown.

Phil


--
mhquay
------------------------------------------------------------------------
Posted via OziPilots Online [ http://www.OziPilotsOnline.com.au ]
- A website for Australian Pilots regardless of when, why, or what they fly -

[Peter Duniho]

"Bill Denton" > wrote in message
...
> And to all of you, my sincerest apologies for being such a pain in the
> ass.

Apology accepted. :) At least you didn't call anyone any names...which,
around here, is a shining compliment indeed. :)

[Marc J. Zeitlin]

Phil wrote:

> Climbing - Lift is Greater than weight
> Level - Lift = weight
> Descending (including landing) - Lift if less than weight

This is substantially incorrect. As long as there's no acceleration in
the vertical or horizontal direction, lift and weight are essentially
equal, whether climbing, descending, or flying at a level altitude.
F=ma, and all that. If a=1, then L=W. This is a common misconception,
and until the climb or descent angle gets large, so that thrust/drag
become a substantial portion of the vertical component of force, L=W.

You don't climb because you've got excess lift - you climb because you
had excess lift for a short period of time which accelerated you
vertically so that you have a upwardly vertical component of velocity.
Conversely, you descend because you had insufficient lift for a short
period of time which accelerated you vertically so that you have a
downwardly vertical component of velocity. The L<>W periods were short,
and are NOT the steady state conditions.

> The stall is uncontrolled "flying" and the only time this should
happen
> whilst "flying" is in stall recovery practice, aerobatics and
sometimes
> a second prior to touchdown.

Stalls can be completely "controlled" flying. I fly a COZY canard
aircraft, and I can fly all day with the canard stalled. I've done so
straight and level and in up to 60 degree banked turns. I've flown in
an acquaintance's Glastar (not a canard - looks a lot like a C-150), and
was able to do pretty much the same (although he only demonstrated 30
degree banked turns while stalled). In both aircraft, we maintained
full control at all times.

Just because your C-150, C-172 or Warrior (what I used to fly) can't do
it doesn't mean that that's the be-all and end-all of aerodynamics :-).

--
Marc J. Zeitlin
http://marc.zeitlin.home.comcast.net/
http://www.cozybuilders.org/
Copyright (c) 2004

[Andrew Sarangan]

At high pitch attitudes, due to the vertical component of thrust, the
lift could actually be LESS than the weight during a climb.


"Marc J. Zeitlin" > wrote in news:hAdod.374264
$wV.338235@attbi_s54:

> Phil wrote:
>
>> Climbing - Lift is Greater than weight
>> Level - Lift = weight
>> Descending (including landing) - Lift if less than weight
>
> This is substantially incorrect. As long as there's no acceleration
in
> the vertical or horizontal direction, lift and weight are essentially
> equal, whether climbing, descending, or flying at a level altitude.
> F=ma, and all that. If a=1, then L=W. This is a common
misconception,
> and until the climb or descent angle gets large, so that thrust/drag
> become a substantial portion of the vertical component of force, L=W.
>
> You don't climb because you've got excess lift - you climb because you
> had excess lift for a short period of time which accelerated you
> vertically so that you have a upwardly vertical component of velocity.
> Conversely, you descend because you had insufficient lift for a short
> period of time which accelerated you vertically so that you have a
> downwardly vertical component of velocity. The L<>W periods were
short,
> and are NOT the steady state conditions.
>
>> The stall is uncontrolled "flying" and the only time this should
> happen
>> whilst "flying" is in stall recovery practice, aerobatics and
> sometimes
>> a second prior to touchdown.
>
> Stalls can be completely "controlled" flying. I fly a COZY canard
> aircraft, and I can fly all day with the canard stalled. I've done so
> straight and level and in up to 60 degree banked turns. I've flown in
> an acquaintance's Glastar (not a canard - looks a lot like a C-150),
and
> was able to do pretty much the same (although he only demonstrated 30
> degree banked turns while stalled). In both aircraft, we maintained
> full control at all times.
>
> Just because your C-150, C-172 or Warrior (what I used to fly) can't
do
> it doesn't mean that that's the be-all and end-all of aerodynamics
:-).
>

[Greg Esres]

<<I suppose it is possible that you can reach max elevator
without reaching critical AOA. But I think that is unlikely, because
that would mean you will never be able to perform power-off stalls in
level unaccelerated flight.>>

The horizontal stabilizer and elevator are sized so that you can reach
max lift coefficient under the most extreme conditions, which will be
forward CG and in ground effect.

Since GE increases the stability of the aircraft, it is possible that
you could stall at altitude, but not close to the ground.