A dumb doubt on stalls

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

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


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

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

"Jim Macklin" wrote in message
news:zZTmg.49464$ZW3.45524@dukeread04...
Maybe, I'm going to take a poll and see what I should do.

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

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

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

--Gary

James H. Macklin
ATP,CFI,A&P

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

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

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

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

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

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

Is Buffy the Vampire Slayer based on fact?



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

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

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

--Gary

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

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

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

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

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

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

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

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

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

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

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

OK, you all can beat me up now.

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

1) Stall warning buzzer goes off.

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

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

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

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

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

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

--Gary

Roy Smith wrote:

In article ,
Gary Drescher wrote:

"Jim Macklin" wrote in message
news:q2Ymg.49475$ZW3.39824@dukeread04...

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

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


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

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

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

Matt

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

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



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

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

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

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

However:

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

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

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

In other words, when you write:

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

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

Pete

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

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

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

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

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

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

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

1) Stall warning buzzer goes off.

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

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

LOL

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