Who does flight plans?

None of the a/c flown by most of us can be 'flown' while stalled no matter how much engine power is applied.

Then what am I doing when I practice stalls at altitude, holding the
aircraft at the stall buffet? I suppose that's not fully stalled yet,
and when it does fully stall I would lose altitude, but ok, fly it juat
above this speed (unstalled) six inches above the runway, and reduce power.

I don't reccomend this, but put it out since it would not be impossible
to do, and would result in a full stall greaser if all conditions were
right.

Jose
--
"Never trust anything that can think for itself, if you can't see where
it keeps its brain."
(chapter 10 of book 3 - Harry Potter).
for Email, make the obvious change in the address.

Recently, Jose posted:

None of the a/c flown by most of us can be 'flown' while stalled no
matter how much engine power is applied.

Then what am I doing when I practice stalls at altitude, holding the
aircraft at the stall buffet?

You're holding the aircraft at just above the stall speed. When you're
stalled, you're falling, not flying.

What I thought you were describing in your earlier post was there is
adequate power to remain in flight strictly on the engine alone. Think
F-18, not C-172. ;-)

I don't reccomend this, but put it out since it would not be
impossible to do, and would result in a full stall greaser if
all conditions were right.

What you seem to describing now is one where you reach stall speed at
exactly the point where your wheels touch down. What's the point in that,
when you can grease it on at 2-3 kts above stall without the risk of being
wrong and dropping, or hitting a gust and being lifted a few feet and
*then* dropping because you don't have the airspeed to fly?

Neil

What you seem to describing now is one where you reach stall speed at
exactly the point where your wheels touch down. What's the point in that,
when you can grease it on at 2-3 kts above stall without the risk of being
wrong and dropping, or hitting a gust and being lifted a few feet and
*then* dropping because you don't have the airspeed to fly?

I was taking issue with the idea that a greaser full stall landing is
self-contradictory.

Jose
--
"Never trust anything that can think for itself, if you can't see where
it keeps its brain."
(chapter 10 of book 3 - Harry Potter).
for Email, make the obvious change in the address.

Jose wrote:
I was taking issue with the idea that a greaser full stall landing is
self-contradictory.

Well, lot's of semantic problems in this whole discussion. I would say
that what people commonly *call* a full stall is not a good way to
grease it on. I would also say that what is called a full stall landing
is actually a landing where power is off, and the plane is at an
attitude and speed where you run out of elevator authority just as you
touch the ground - perhaps the wing is stalled but what I think is
that the nose is simply dropping to continue flying as you run out of
elevator. The only way out of this is to add power or let the nose drop
until more airspeed is gained.

I can do this in the Maule when I make a minimum speed approach, flare
at the right moment, and touch the ground just as the wheel is pulled
all the way back. Not a good way to grease it on but it is wonderful
thing when it happens.

Normally, I come in at a normal approach speed, flare to the 3 point
attitude and touch down. If I pull back too far or too fast, I can and
will touch the tailwheel first.

So I agree that what we think of as a full stall landing, can be greased
on. It's just not the best way. I also suggest that the idea of
holding it off with power at a high angle of attack (dragging it in) is
neither a 'full stall landing' nor a good way to grease it.

Perhaps just a different perspective.

Recently, T o d d P a t t i s t posted:

There are a couple of points I'd like to make in this
thread.

"Neil Gould" wrote:

None of the a/c flown by most of us can be 'flown' while stalled no
matter how much engine power is applied.

Then what am I doing when I practice stalls at altitude, holding the
aircraft at the stall buffet?

You're holding the aircraft at just above the stall speed.

That is indeed what he's doing.

When you're stalled, you're falling, not flying.

This is a matter of semantics. I consider myself to be
flying even when practicing spins with both wings stalled.

I thought one could only maintain a spin where *one* wing is stalled, and
the other not? If both wings stall, the spin should stop and the plane
should fall.

First point:
I also consider aerobatics pilots to be flying when using a
powerful engine to supplement reduced lift and fly with both
wings stalled.

Well, they're "flying" by power lift, in the same sense that a Harrier is
"flying" when hovering. The wings are irrelevant in those situations. So,
in the context of "greasing on" a full-stall landing in a typical SEL,
those scenarios are irrelevant to the OP.

[...]
The
point I'm making here is that a stalled wing still produces
lots of lift. In fact, near stall, it's producing nearly
the maximum lift that the wing is capable of producing.

Is that like saying, "Even those that don't have an income can purchase
the most expensive plane they can afford"? ;-)

Second Point:
It is exceptionally difficult to actually get to a full
stall attitude for landing. What is often called a "full
stall landing" or "3 point landing" does not actually have
the wing at stall AOA. Many aircraft would hit their tail
if they were low enough to safely land and the wing was at
stall AOA.

I completely disagree with this notion. The AOA is a vector of the
relative direction of travel through air. There is no requirement that
there be a nose-high attitude in a stall, only that the wind traveling
over the wing is lower than what is required to produce lift. It isn't
difficult to hold a typical SEL aircraft in a nose-down stall, and in
fact, a descending turning stall is a required manouvre in the private
PTS.

Neil

"Neil Gould" wrote in message
. ..
Recently, T o d d P a t t i s t posted:

This is a matter of semantics. I consider myself to be
flying even when practicing spins with both wings stalled.

I thought one could only maintain a spin where *one* wing is stalled, and
the other not? If both wings stall, the spin should stop and the plane
should fall.

Anyone trying to describe spin aerodynamics in one or two sentences is
doomed to failure. That said, to think of it as a "one wing stalled,
one wing flying" scenario is insufficient, IMHO. Each wing is creating
different amounts of lift, true...and a stall has occurred, also true. But
both wings can still be generating lift, while still both remaining stalled.
It's the asymmetric lift that causes the spin, regardless of whether both
wings are stalled or not.

First point:
I also consider aerobatics pilots to be flying when using a
powerful engine to supplement reduced lift and fly with both
wings stalled.

Well, they're "flying" by power lift, in the same sense that a Harrier is
"flying" when hovering. The wings are irrelevant in those situations. So,
in the context of "greasing on" a full-stall landing in a typical SEL,
those scenarios are irrelevant to the OP.

If the wing has non-zero motion relative to the air, it has a defined
angle-of-attack, and thus can be determined to be stalled or not stalled.
Whether the wing is providing any significant lift contribution to helping
the airplane maintain altitude is irrelevant to the question of whether the
airplane is flying with both wings stalled or not.

In particular, Todd's comment simply corrects the statement that "when
you're stalled, you're falling, not flying". Using power to keep oneself
aloft is still "flying", even if the wings are stalled. Thus, it is not
always true that "when you're stalled, you're...not flying", even if it IS
true in most situations.

The
point I'm making here is that a stalled wing still produces
lots of lift. In fact, near stall, it's producing nearly
the maximum lift that the wing is capable of producing.

Is that like saying, "Even those that don't have an income can purchase
the most expensive plane they can afford"? ;-)

That depends on what you mean by "don't have an income". It's more like
saying that "even those whose income has peaked and is now going back down
can purchase an airplane almost as expensive as one they could have afforded
at their peak income".

In other words, what Todd is saying is that lift doesn't just quit in a
discontinuous way at the stall. If you look at the graph of lift versus
angle of attack, the peak of that graph occurs right at the stalling angle
of attack, and then starts to drop off from there. It does drop quite a bit
more rapidly than the other side of the graph where lift is increasing, but
it doesn't just jump to zero.

Assuming you could maintain control of the airplane in a fashion to ensure
that you exceeded the stalling angle of attack only by a tiny fraction of a
degree, you would wind up getting almost as much lift as you were getting
right at the instant you stalled.

There are, of course, other issues. The graph I'm talking about is actually
the lift coefficient graph; actual lift depends on the lift coefficient
(angle of attack) and airspeed. Drag increases dramatically at stall, and
it would require a lot of extra power to maintain an airspeed sufficient to
produce lift equal to the airplane's weight, flying just past the stalling
angle of attack. But it certainly is theoretically possibly.

Second Point:
It is exceptionally difficult to actually get to a full
stall attitude for landing. What is often called a "full
stall landing" or "3 point landing" does not actually have
the wing at stall AOA. Many aircraft would hit their tail
if they were low enough to safely land and the wing was at
stall AOA.

I completely disagree with this notion. The AOA is a vector of the
relative direction of travel through air.

The AOA is the "angle-of-attack". It's not a vector at all, never mind the
one you describe. It is true that the AOA is relative to direction of
travel through air (ie the "relative wind").

There is no requirement that
there be a nose-high attitude in a stall, only that the wind traveling
over the wing is lower than what is required to produce lift. It isn't
difficult to hold a typical SEL aircraft in a nose-down stall, and in
fact, a descending turning stall is a required manouvre in the private
PTS.

Read Todd's statement again. He is clearly talking only about the situation
during a landing. The motion of the aircraft through the air just prior to
touchdown is necessarily nearly or precisely parallel to the ground. And it
is true that with most airplanes, the stalling angle-of-attack produces a
pitch angle so nose-high that the tail will hit the ground before the main
gear does.

Which was the entire point of the phrase Todd uses: "if they were low enough
to safely land and the wing was at stall AOA". If they are low enough to
land and are at a nose-down stalling AOA, they are milliseconds from
crashing. Which is clearly not the scenario we're talking about here.

You are certainly correct that an airplane can be stalled in any attitude.
But that in no way provides a basis for disagreement with Todd's statements.

Pete

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

If you want to get closer to a true stall at landing, you'd
probably want to come in about a foot or two higher and
really get the nose up before touching the tail. Of course
your Maule probably wouldn't be so happy with that technique

Maules are not happy with that technique. When a Maule is in three-point
attitude, it is not stalled. Power-off stall in no-wind conditions occurs when
the mains are about 6" higher than the tailwheel.

George Patterson
Why do men's hearts beat faster, knees get weak, throats become dry,
and they think irrationally when a woman wears leather clothing?
Because she smells like a new truck.

Recently, Peter Duniho posted:

In particular, Todd's comment simply corrects the statement that "when
you're stalled, you're falling, not flying". Using power to keep
oneself aloft is still "flying", even if the wings are stalled.
Thus, it is not always true that "when you're stalled, you're...not
flying", even if it IS true in most situations.

Then, the issue is one trying to make an absolute statement out of one
intended only in the context of the discussion, specifically, "full stall
greasers" in the typical SEL aircraft. Any discussion about other forms of
flying, whether it be in hovering Harriers or personal batwings are
irrelevant to that context.

In other words, what Todd is saying is that lift doesn't just quit in
a discontinuous way at the stall. If you look at the graph of lift
versus angle of attack, the peak of that graph occurs right at the
stalling angle of attack, and then starts to drop off from there. It
does drop quite a bit more rapidly than the other side of the graph
where lift is increasing, but it doesn't just jump to zero.

I wasn't claiming that it does. It's just that the amount of lift after
stall isn't sufficient to be relevant.

There are, of course, other issues. The graph I'm talking about is
actually the lift coefficient graph; actual lift depends on the lift
coefficient (angle of attack) and airspeed. Drag increases
dramatically at stall, and it would require a lot of extra power to
maintain an airspeed sufficient to produce lift equal to the
airplane's weight, flying just past the stalling angle of attack.
But it certainly is theoretically possibly.

Of course, if you have enough power. That's why my original reply stated,
"Think F-18..." This theoretical possibility isn't very relevant to the
context of the post to which I originally replied, e.g., "full-stall
greased landings" in a typical SEL.

Second Point:
It is exceptionally difficult to actually get to a full
stall attitude for landing. What is often called a "full
stall landing" or "3 point landing" does not actually have
the wing at stall AOA. Many aircraft would hit their tail
if they were low enough to safely land and the wing was at
stall AOA.

I completely disagree with this notion. The AOA is a vector of the
relative direction of travel through air.

The AOA is the "angle-of-attack". It's not a vector at all, never
mind the one you describe. It is true that the AOA is relative to
direction of travel through air (ie the "relative wind").

One doesn't have directional motion *without* a vector. ;-)

"Vector...Etymology: New Latin, from Latin, carrier, from vehere to
carry -- more at WAY
1 a : a quantity that has magnitude and direction and that is commonly
represented by a directed line segment whose length represents the
magnitude and whose orientation in space represents the direction..."

When one refers to the "angle of attack" (and, yes, I know that "AOA" is
the acronym), one is definitely referring to motion having both direction
and magnitude. "Relative wind" is just a non-technical way to state this.
However, it would have been better stated if I had said "... relative
direction of _the wing's_ travel...", even though the typical SEL's wing
pitch isn't drastically different from the rest of the aircraft. ;-)

There is no requirement that
there be a nose-high attitude in a stall, only that the wind
traveling over the wing is lower than what is required to produce
lift. It isn't difficult to hold a typical SEL aircraft in a
nose-down stall, and in fact, a descending turning stall is a
required manouvre in the private PTS.

Read Todd's statement again. He is clearly talking only about the
situation during a landing. The motion of the aircraft through the
air just prior to touchdown is necessarily nearly or precisely
parallel to the ground.

My reply specifically separates the AOA from any ground reference.

And it is true that with most airplanes, the
stalling angle-of-attack produces a pitch angle so nose-high that the
tail will hit the ground before the main gear does.

I responded to that. In the context of landing, if one flies slowly enough
to stall, one can stall "flat" relative to the ground because the decrease
in forward "relative wind" increases the AOA. That is what my remark
addresses.

You are certainly correct that an airplane can be stalled in any
attitude. But that in no way provides a basis for disagreement with
Todd's statements.

I think it does with regard to necessarily hitting the tail before
stalling.

Neil

"Neil Gould" wrote in message
...
[...] Any discussion about other forms of
flying, whether it be in hovering Harriers or personal batwings are
irrelevant to that context.

Then perhaps you should take that up with the person who brought up such
examples. Todd was not that person. Oh, wait...it was YOU that mentioned
the F-18.

(Minor nitpick: I don't recall for sure whether the F-18 actually has more
thrust than weight; I believe that the F-16 does, and it's the only airplane
I understood to have that characteristic. I will continue saying "F-18" in
this post, with the assumption that you know for a fact it also has more
thrust than weight...perhaps it's just one of the later models, like the
Super Hornet, that does).

I wasn't claiming that it does. It's just that the amount of lift after
stall isn't sufficient to be relevant.

That's a false claim. As the lift drops off in a continuous manner, there
is a region "after stall" where the lift coefficient is just as high as
usable regions "before stall".

You may equivocate on whether a pilot can maintain the airplane at the
angle-of-attack required to obtain that "after stall" coefficient of lift.
But the fact remains that the lift is theoretically obtainable. As long as
you don't want a lift coefficient very close to the maximum lift coefficient
for the wing, it may not even be that hard to obtain the desired
coefficient.

There are, of course, other issues. The graph I'm talking about is
actually the lift coefficient graph; actual lift depends on the lift
coefficient (angle of attack) and airspeed. Drag increases
dramatically at stall, and it would require a lot of extra power to
maintain an airspeed sufficient to produce lift equal to the
airplane's weight, flying just past the stalling angle of attack.
But it certainly is theoretically possibly.

Of course, if you have enough power. That's why my original reply stated,
"Think F-18..."

I fear we're back to square one. The F-18 has more power than is necessary.
You only need enough power to overcome the drag. You don't need enough
power to overcome weight, which is what you seem to be saying.

This theoretical possibility isn't very relevant to the
context of the post to which I originally replied, e.g., "full-stall
greased landings" in a typical SEL.

Sure it is. It discusses the actual aerodynamics, allowing someone to
consider what would be required to make a "full-stall greaser". Physical
characteristics of most airplanes preclude actually stalling the wing when
in a safe landable position (mainly the issue of the tail winding up too low
for a safe landing), but otherwise there's no obvious reason one could not
only make a "full-stall greaser", but could actually *fly* the airplane onto
the runway in the stalled condition.

In fact, if anything (again, ignoring the geometry of the situation) the
landing scenario is the most likely scenario in which a pilot could maintain
the post-stall condition, since ground effect would dramatically reduce
induced drag, induced drag being a primary reason that maintaining the
airplane in a flying condition past the stall is so difficult.

Of course, as Todd correctly pointed out, the physical geometry of most
airplanes preclude stalling the airplane when in a position for a safe
landing (ie just above the runway). But you incorrectly attempt to dispute
that as well.

The AOA is the "angle-of-attack". It's not a vector at all, never
mind the one you describe. It is true that the AOA is relative to
direction of travel through air (ie the "relative wind").

One doesn't have directional motion *without* a vector. ;-)

I never said there were no vectors. I said the angle-of-attack is not a
vector.

"Vector...Etymology: New Latin, from Latin, carrier, from vehere to
carry -- more at WAY
1 a : a quantity that has magnitude and direction and that is commonly
represented by a directed line segment whose length represents the
magnitude and whose orientation in space represents the direction..."

When in doubt, post a definition? Seriously...what purpose was that
supposed to serve?

When one refers to the "angle of attack" (and, yes, I know that "AOA" is
the acronym), one is definitely referring to motion having both direction
and magnitude.

No, they are not. The angle-of-attack is a specific angle, measured between
the wing's chord and the relative wind. In fact, a motionless airplane can
still have an angle-of-attack, just as long as there is some wind.

"Relative wind" is just a non-technical way to state this.

Actually, "relative wind" is a *technical* way to state the apparent wind
relative to the chord of the wing. But angle-of-attack is something else
entirely. Relative wind is indeed a vector. Angle-of-attack is not.

However, it would have been better stated if I had said "... relative
direction of _the wing's_ travel...", even though the typical SEL's wing
pitch isn't drastically different from the rest of the aircraft. ;-)

The angle of incidence (which is what you appear to be talking about
now...that is, the angle between the wing chord and the longitudinal axis of
the airplane) is yet again something else entirely different from
angle-of-attack. The phrase you suggest as a replacement for
angle-of-attack (that is, "relative direction of _the wing's_ travel") would
not be a suitable replacement at all for "angle-of-attack", though it might
serve as an synonymous phrase for "relative wind".

The confusion here is not between the airplane's pitch angle and the wing's
angle-of-attack. It's your insistence on calling the angle-of-attack a
vector, when it's a scalar (and, it appears, your confusion between
"relative wind" and "angle-of-attack").

My reply specifically separates the AOA from any ground reference.

Actually, your reply implies that Todd doesn't understand that the
angle-of-attack isn't measure relative to the ground. He does understand
that, but the fact that angle-of-attack isn't measured relative to the
ground doesn't change the fact that you can't stall most planes while in a
position for a safe landing.

And it is true that with most airplanes, the
stalling angle-of-attack produces a pitch angle so nose-high that the
tail will hit the ground before the main gear does.

I responded to that. In the context of landing, if one flies slowly enough
to stall, one can stall "flat" relative to the ground because the decrease
in forward "relative wind" increases the AOA. That is what my remark
addresses.

Your claim is incorrect. As long as the airplane is flying just above the
ground, the relative wind is parallel to the ground. No change in the
angle-of-attack will occur from any decrease in speed, not directly.

It is simply impossible to do what you suggest one might do. If one "flies
slowly enough to stall", the angle-of-attack is at the stalling
angle-of-attack, period. Furthermore, if one flies at a constant altitude
(as one must do when landing an airplane, once over the runway), the
relative wind is parallel to the ground, and thus the airplane's pitch angle
is the same as the wing's angle-of-attack (ignoring the angle of incidence,
of course).

What WILL happen is that as the aircraft slows, the pitch angle of the
aircraft will need to be increased, so as to continually increase the
angle-of-attack of the wing. The increase in AOA increases the lift
coefficient, compensating for the reduction in airspeed to maintain a lift
force equal to the airplane's weight. If you do not increase the pitch
angle, the airplane will simply descend onto the runway.

You will not stall "flat" relative to the ground. Only one of two things
can happen in the scenario you describe. You will either prevent the
airplane from touching the runway by continually increase the
angle-of-attack (which means no stall "flat" relative to the ground) , or
the airplane will descend and touch the runway (again, no stall "flat"
relative to the ground). In *either* case, the airplane will touch the
runway before the wing stalls, assuming a safe landing.

You are certainly correct that an airplane can be stalled in any
attitude. But that in no way provides a basis for disagreement with
Todd's statements.

I think it does with regard to necessarily hitting the tail before
stalling.

You think wrong.

Pete

Recently, Peter Duniho posted:

"Neil Gould" wrote in message
I wasn't claiming that it does. It's just that the amount of lift
after stall isn't sufficient to be relevant.

That's a false claim. As the lift drops off in a continuous manner,
there is a region "after stall" where the lift coefficient is just as
high as usable regions "before stall".

You may equivocate on whether a pilot can maintain the airplane at the
angle-of-attack required to obtain that "after stall" coefficient of
lift. But the fact remains that the lift is theoretically obtainable.
As long as you don't want a lift coefficient very close to the
maximum lift coefficient for the wing, it may not even be that hard
to obtain the desired coefficient.

Again, the _context_ is a response to Matt & Jose's claim of controlling a
typical SEL to "greaser full-stall landings". I was agreeing with George
that this is probably not what they were experiencing, and Todd's
explanation regarding the high pitch angle typical of stall speeds is in
agreement with this, albeit for other reasons. So, in context, how is your
theoretically available lift relevant?

When one refers to the "angle of attack" (and, yes, I know that
"AOA" is the acronym), one is definitely referring to motion having
both direction and magnitude.

No, they are not. The angle-of-attack is a specific angle, measured
between the wing's chord and the relative wind. In fact, a
motionless airplane can still have an angle-of-attack, just as long
as there is some wind.

If there is wind, there is motion, direction and magnitude relative to the
wing, ergo, a vector. If there is no wind, there is no "attack", and that
angle then describes something entirely different.

[...]
However, it would have been better stated if I had said "...
relative direction of _the wing's_ travel...", even though the
typical SEL's wing pitch isn't drastically different from the rest
of the aircraft. ;-)

The angle of incidence (which is what you appear to be talking about
now...that is, the angle between the wing chord and the longitudinal
axis of the airplane) is yet again something else entirely different
from angle-of-attack.

Two different things are being described. In context (the direction of
travel), the difference between the AOA and the angle of incidence is not
"drastically different".

[...]
The confusion here is not between the airplane's pitch angle and the
wing's angle-of-attack. It's your insistence on calling the
angle-of-attack a vector, when it's a scalar (and, it appears, your
confusion between "relative wind" and "angle-of-attack").

To be a scalar, it would have to lack motion, ergo no "attack".

[...]
I responded to that. In the context of landing, if one flies slowly
enough to stall, one can stall "flat" relative to the ground because
the decrease in forward "relative wind" increases the AOA. That is
what my remark addresses.

Your claim is incorrect. As long as the airplane is flying just
above the ground, the relative wind is parallel to the ground. No
change in the angle-of-attack will occur from any decrease in speed,
not directly.

My claim is that if the aircraft is flying parallel to the ground just
before touch-down, it isn't stalled.

[...]
It is simply impossible to do what you suggest one might do. If one
"flies slowly enough to stall", the angle-of-attack is at the stalling
angle-of-attack, period.

And all I'm saying is that this is independent of the pitch angle relative
to the ground.

[...]
What WILL happen is that as the aircraft slows, the pitch angle of the
aircraft will need to be increased, so as to continually increase the
angle-of-attack of the wing.

We are describing the same phenomena from two perspectives. In the context
of my usage, if one maintains the pitch angle as the aircraft slows, the
AOA will continually increase (normally, the pitch angle changes as the
aircraft slows). But, again, the context of what happens during landing;
one is maintaining a safe pitch angle as the aircraft slows, not
necessarily increasing the pitch angle to insure a stall.

[...]
In *either* case, the
airplane will touch the runway before the wing stalls, assuming a
safe landing.

In fact, I stated that the risk is something quite different from a safe
landing.

Neil