Problems in a commercial flight

[megaMAX]

Hello everybody,
I want to tell you what's happened during a Finnair flight from
Helsinki to Milan, I'm not an expert of flight.

During the entire flight, I noticed that the aircraft was continuosly
rolling to right, and the pilot was correcting every 10-20 seconds the
attitude. I noticed this, because I was looking to the right wing and
the wing was continuosly going down of few centimeters, and after few
seconds there was a slight correction.

During landing, the aircraft was definitively rolling clockwise, in
fact when we touched the ground, it was really yawing and sliding, and
the pilot had to take a decise correction in order to align the
aircraft to the track.

I'm really not an expert, but I was wondering:

- what could have been the problem? The right engine?
- the pilot behaved correctly, completing the flight until destination
and trying this landing? An intermediate step could have been better?
- we have been in some danger, during the flight or at the moment of
landing?
- this episodes are made pubblic in some register, or the companies
try to hide them as much as possible?

Thanks!
Max

[B A R R Y]

On Wed, 14 Mar 2007 00:08:34 +0100, megaMAX
> wrote:

>Hello everybody,
>I want to tell you what's happened during a Finnair flight from
>Helsinki to Milan, I'm not an expert of flight.

Obviously...

[megaMAX]

On Tue, 13 Mar 2007 23:45:10 GMT, B A R R Y
> wrote:

>>Hello everybody,
>>I want to tell you what's happened during a Finnair flight from
>>Helsinki to Milan, I'm not an expert of flight.
>
>Obviously...

And so what? I'm just asking since I don't know if it's normal or
what...


Max

[Bob Noel]

In article >,
megaMAX > wrote:

> During the entire flight, I noticed that the aircraft was continuosly
> rolling to right, and the pilot was correcting every 10-20 seconds the
> attitude. I noticed this, because I was looking to the right wing and
> the wing was continuosly going down of few centimeters, and after few
> seconds there was a slight correction.

a wing movement of a few centimeters is nothing.

don't worry about it.

--
Bob Noel
(gave up lookingn for a particular sig the lawyer will)

[Mxsmanic]

megaMAX writes:

> During the entire flight, I noticed that the aircraft was continuosly
> rolling to right, and the pilot was correcting every 10-20 seconds the
> attitude. I noticed this, because I was looking to the right wing and
> the wing was continuosly going down of few centimeters, and after few
> seconds there was a slight correction.

A few centimeters? What type of aircraft was it?

Most commercial flights are flown on autopilot for the vast majority of the
trip. Thus you would have seen autopilot corrections, not pilot corrections.

> - what could have been the problem? The right engine?

A crosswind is the most likely cause. Possible causes that are orders of
magnitude less likely include asymmetric thrust (including one engine shut
down, depending on the aircraft). Asymmetry in control surfaces. Bad trim.

> - the pilot behaved correctly, completing the flight until destination
> and trying this landing? An intermediate step could have been better?

Most likely there was nothing wrong, so there was nothing that needed to be
done. Constant small corrections are normal in flight. If there are
substantial winds aloft (and there usually are), the corrections are likely to
be mostly in one direction.

> - we have been in some danger, during the flight or at the moment of
> landing?

From your description, there is no reason to believe that the flight was in
any danger, and the corrections sound like nothing more than what is normal
for any flight.

> - this episodes are made pubblic in some register, or the companies
> try to hide them as much as possible?

There's nothing to hide or record for a normal flight.

--
Transpose mxsmanic and gmail to reach me by e-mail.

[megaMAX]

On Wed, 14 Mar 2007 01:18:33 +0100, Mxsmanic >
wrote:

>Most commercial flights are flown on autopilot for the vast majority of the
>trip. Thus you would have seen autopilot corrections, not pilot corrections.

Yes, this is really probable, since it was a very regular and periodic
correction, every few seconds.

>Most likely there was nothing wrong, so there was nothing that needed to be
>done. Constant small corrections are normal in flight. If there are
>substantial winds aloft (and there usually are), the corrections are likely to
>be mostly in one direction.

Ok, but what about landing? The landing runway wasn't in the same
direction of the rest of the flight, so the wind probably was blowing
in a different direction.

My sensation was that, at the moment of landing, the pilot was really
not able to have a good trim due to a decise clockwise roll, that he
was really not able to correct with the normal actions, despite of
various tentatives. The impression was like that the right engine was
not enough "powerful", or the airplane was heavier on the right side.
Of course, impressions of a not-expert people.

But since I had a large number of flights in my life and I know what
happens in case of lateral wind, also during landing, I repeat that my
sensation was not of lateral wind.

>From your description, there is no reason to believe that the flight was in
>any danger, and the corrections sound like nothing more than what is normal
>for any flight.

Ok, thank you: I was really calm during the flight, only after landing
I was wondering about what has happened and I was curious about that.

Massimo

[Mxsmanic]

megaMAX writes:

> Ok, but what about landing?

There is often wind at the surface during landing as well. If the wind is
significant, the pilot must adjust for it as he lands the aircraft (most
landings are done manually by the pilot, although many modern airliners can
land themselves if the pilot configures them to do so). If the wind is
steady, the pilot applies a constant correction to keep the aircraft aligned
with the runway. If it is gusting, he may have to constantly adjust the
controls to maintain alignment. You would see this as continual changes in
attitude, with slight rolling to one side or the other (the aircraft must roll
in order to turn).

> The landing runway wasn't in the same
> direction of the rest of the flight, so the wind probably was blowing
> in a different direction.

Winds often blow in different directions at different altitudes, including at
the surface, so the correction applied must change as the altitude changes.

> My sensation was that, at the moment of landing, the pilot was really
> not able to have a good trim due to a decise clockwise roll, that he
> was really not able to correct with the normal actions, despite of
> various tentatives.

The sensations are often stronger than the actual corrections applied. Most
airliners are flown in an exceedingly docile way, which gives no hint of the
maneuvers that they can safely undertake. If the pilot had to make greater
than usual corrections, this could easily give the impression that the
aircraft is moving dramatically, even though it is not. It's moving more than
it normally does, but it is not moving in any unsafe way. It's just that
normal flight is so gentle (deliberately so, since this helps ensure the
comfort of passengers) that any departure from this seems extreme in
comparison.

> The impression was like that the right engine was
> not enough "powerful", or the airplane was heavier on the right side.
> Of course, impressions of a not-expert people.

The engines are more than powerful enough to ensure safe flight. Pilots are
able to land a twin-engine aircraft with just one engine, and aircraft with
more than two engines are even easier to land with an engine out. However,
engines almost never fail (most airline pilots will go through their entire
careers without experiencing an engine failure), so it's unlikely that an
engine problem occurred in this case.

> But since I had a large number of flights in my life and I know what
> happens in case of lateral wind, also during landing, I repeat that my
> sensation was not of lateral wind.

You can't feel a lateral wind. You can only feel corrections made for it, and
sometimes not even that. Without being in the cockpit and seeing the
instruments, it can be difficult to determine just how the aircraft is moving,
from the viewpoint of a passenger with only a small window on one side of the
plane.

> Ok, thank you: I was really calm during the flight, only after landing
> I was wondering about what has happened and I was curious about that.

Do you have a fear of flying? People who become concerned about a few
centimeters of movement in a wingtip or who interpret unusual experiences as
possible engine failures often do.

--
Transpose mxsmanic and gmail to reach me by e-mail.

[Matt Whiting]

megaMAX wrote:
> Hello everybody,
> I want to tell you what's happened during a Finnair flight from
> Helsinki to Milan, I'm not an expert of flight.
>
> During the entire flight, I noticed that the aircraft was continuosly
> rolling to right, and the pilot was correcting every 10-20 seconds the
> attitude. I noticed this, because I was looking to the right wing and
> the wing was continuosly going down of few centimeters, and after few
> seconds there was a slight correction.
>
> During landing, the aircraft was definitively rolling clockwise, in
> fact when we touched the ground, it was really yawing and sliding, and
> the pilot had to take a decise correction in order to align the
> aircraft to the track.
>
> I'm really not an expert, but I was wondering:
>
> - what could have been the problem? The right engine?
> - the pilot behaved correctly, completing the flight until destination
> and trying this landing? An intermediate step could have been better?
> - we have been in some danger, during the flight or at the moment of
> landing?
> - this episodes are made pubblic in some register, or the companies
> try to hide them as much as possible?
>
> Thanks!
> Max

That is normal. Most airplanes will "wander" just a little when on
autopilot.

Matt

[C J Campbell[_1_]]

On 2007-03-13 17:43:50 -0700, megaMAX
> said:

> On Wed, 14 Mar 2007 01:18:33 +0100, Mxsmanic >
> wrote:
>
>> Most commercial flights are flown on autopilot for the vast majority of the
>> trip. Thus you would have seen autopilot corrections, not pilot corrections.

Just so you know, Msxmanic does not know any more about flight than you
do. He is not a pilot. He is just some nut who hangs out here and
pretends to know what he is talking about.

--
Waddling Eagle
World Famous Flight Instructor

[C J Campbell[_1_]]

On 2007-03-13 16:08:34 -0700, megaMAX
> said:

> Hello everybody,
> I want to tell you what's happened during a Finnair flight from
> Helsinki to Milan, I'm not an expert of flight.
>
> During the entire flight, I noticed that the aircraft was continuosly
> rolling to right, and the pilot was correcting every 10-20 seconds the
> attitude. I noticed this, because I was looking to the right wing and
> the wing was continuosly going down of few centimeters, and after few
> seconds there was a slight correction.

Not unusual at all. It could just be normal cycling of the autopilot.

>
> During landing, the aircraft was definitively rolling clockwise, in
> fact when we touched the ground, it was really yawing and sliding, and
> the pilot had to take a decise correction in order to align the
> aircraft to the track.

This is also normal in a crosswind landing. The wind is blowing from
the direction that the wing is down. Since the pilot does not want to
land too much sideways, he will kick the plane around so it points
straight down the runway just before touchdown.

>
> I'm really not an expert, but I was wondering:
>
> - what could have been the problem? The right engine?
> - the pilot behaved correctly, completing the flight until destination
> and trying this landing? An intermediate step could have been better?
> - we have been in some danger, during the flight or at the moment of
> landing?
> - this episodes are made pubblic in some register, or the companies
> try to hide them as much as possible?

Minor problems with the airplane are recorded in the airplane's
logbooks. In the US, accidents are recorded in the NTSB database. Not
all countries maintain such a database, however.

>
> Thanks!
> Max


--
Waddling Eagle
World Famous Flight Instructor

[Mxsmanic]

C J Campbell writes:

> Just so you know, Msxmanic does not know any more about flight than you
> do. He is not a pilot.

Correction: Actually, Mxsmanic knows a great deal, _despite_ not being a
pilot. This is particularly true with respect to large aircraft, since most
of the pilots here are familiar only with the tiny aircraft they fly, whereas
he has studied both small and large aircraft.

More to the point: If you see an error in anything I've said, feel free to
point it out.

> He is just some nut who hangs out here and pretends to know what
> he is talking about.

He doesn't have to pretend. Nor is he so insecure that he must engage in
personal attacks if someone else seems to know more.

--
Transpose mxsmanic and gmail to reach me by e-mail.

[Nils Rostedt]

A movement of a few centimetres at the wingtip is nothing to worry about.
Aircraft in flight may show various oscillating motions. See
http://en.wikipedia.org/wiki/Aircraft_dynamic_modes.

During landing, crosswind gusts may sometimes require significant corrective
input from the pilot. In some rare cases even a go-around is necessary if
the wind blows hard.

If there would be some technical problem, the pilots have a large set of
checklists, diagnostic procedures and automatic diagnostic systems available
which can pinpoint the problem and give instructions how to continue the
flight.


"megaMAX" wrote
> Hello everybody,
> I want to tell you what's happened during a Finnair flight from
> Helsinki to Milan, I'm not an expert of flight.
>
> During the entire flight, I noticed that the aircraft was continuosly
> rolling to right, and the pilot was correcting every 10-20 seconds the
> attitude. I noticed this, because I was looking to the right wing and
> the wing was continuosly going down of few centimeters, and after few
> seconds there was a slight correction.
>
> During landing, the aircraft was definitively rolling clockwise, in
> fact when we touched the ground, it was really yawing and sliding, and
> the pilot had to take a decise correction in order to align the
> aircraft to the track.
>
> I'm really not an expert, but I was wondering:
>
> - what could have been the problem? The right engine?
> - the pilot behaved correctly, completing the flight until destination
> and trying this landing? An intermediate step could have been better?
> - we have been in some danger, during the flight or at the moment of
> landing?
> - this episodes are made pubblic in some register, or the companies
> try to hide them as much as possible?
>
> Thanks!
> Max

[Dave[_3_]]

Soooo..

How come he (MX) was able to give a rather complete and correct
answer to the poster's question?

Care to give it a try?

Dave



On Tue, 13 Mar 2007 22:44:15 -0700, C J Campbell
> wrote:

>On 2007-03-13 17:43:50 -0700, megaMAX
> said:
>
>> On Wed, 14 Mar 2007 01:18:33 +0100, Mxsmanic >
>> wrote:
>>
>>> Most commercial flights are flown on autopilot for the vast majority of the
>>> trip. Thus you would have seen autopilot corrections, not pilot corrections.
>
>Just so you know, Msxmanic does not know any more about flight than you
>do. He is not a pilot. He is just some nut who hangs out here and
>pretends to know what he is talking about.

[**THE-RFI-EMI-GUY**]

I was flying in an Air Jamaica jet many years ago and while cruising
noticed large reddish flames from the exhaust of the Rolls Royce engine.
How "normal" would that be?

--
Joe Leikhim K4SAT
"The RFI-EMI-GUY"©

"Treason doth never prosper: what's the reason?
For if it prosper, none dare call it treason."

"Follow The Money" ;-P

[george]

On Mar 14, 1:06 pm, megaMAX
> wrote:
> On Tue, 13 Mar 2007 23:45:10 GMT, B A R R Y
>
> > wrote:
> >>Hello everybody,
> >>I want to tell you what's happened during a Finnair flight from
> >>Helsinki to Milan, I'm not an expert of flight.
>
> >Obviously...
>
> And so what? I'm just asking since I don't know if it's normal or
> what...

Middle ear infection?

[george]

On Mar 15, 11:59 am, Dave > wrote:
> Soooo..
>
> How come he (MX) was able to give a rather complete and correct
> answer to the poster's question?
>
> Care to give it a try?

More than possible that the poster had a middle ear infection.
Not having instruments and the training to use them while back among
the self loading cargo how could any-one tell what the aircraft was
doing?

[Mxsmanic]

**THE-RFI-EMI-GUY** writes:

> I was flying in an Air Jamaica jet many years ago and while cruising
> noticed large reddish flames from the exhaust of the Rolls Royce engine.
> How "normal" would that be?

It depends on the exact conditions. Were you cruising? Climbing?
Descending? What altitude? How did the engine sound? How long did the
flames last, and what did they look like, exactly?

Normally visible flames don't extend beyond the engine, although if you look
directly into the exhaust of a jet engine you may well be able to see glowing
internal parts. High-performance engines may glow externally as well. And of
course afterburners can produce long flames that extend well beyond the
engine. And so on.

There is jet fuel burning inside a running jet engine all the time, so a
visible flame isn't necessarily a cause for panic or concern.

--
Transpose mxsmanic and gmail to reach me by e-mail.

[Mxsmanic]

george writes:

> More than possible that the poster had a middle ear infection.

I don't see the connection between a middle-ear infection and what he saw or
believed.

> Not having instruments and the training to use them while back among
> the self loading cargo how could any-one tell what the aircraft was
> doing?

One can estimate visually, but with limited visibility this is difficult.
Even pilots cannot depend on visual cues alone, which is why they have
instruments.

--
Transpose mxsmanic and gmail to reach me by e-mail.

[[email protected]]

> Even pilots cannot depend on visual cues alone, which is why they have
> instruments.
>

Yes, they can.
But what do I know, I only fly tiny planes.

-Kees

[Mxsmanic]

Google Plex writes:

> Under which of these conditions, exactly, would large reddish flames from the
> exhaust of a Rolls Royce engine be 'normal'?

I don't know. Ask Rolls-Royce.

> Does Air Jamaica use afterburners?

It's a question of the aircraft and engines, not the airline. Air France and
British Airways have, in the past.

--
Transpose mxsmanic and gmail to reach me by e-mail.

[Mxsmanic]

writes:

> Yes, they can.

No, they cannot, except under ideal conditions, and sometimes not even then.

> But what do I know, I only fly tiny planes.

My thoughts exactly.

--
Transpose mxsmanic and gmail to reach me by e-mail.

[**THE-RFI-EMI-GUY**]

I am the original poster, not MXSMANIC and since I have blocked his posts, some of the thread might be as well.

We were cruising and the flames were well behind the engine, sort of like a small afterburner effect. We flew on without incident. I always wondered what the difference between "running rich" and ENGINE FIRE! might be.

On another AJ flight, the passenger beside me left his seat about the same time the FA was giving her speil about the life vest under the seat. I felt under my seat and found only an empty pocket. I rang the FA and told her that I had no life vest. She said "No problem" and pulled the one out from the temporarily vacant seat next to mine and put it under my seat!





Google Plex wrote:

>MXSMANIC wrote:
>
>
>
>>>I was flying in an Air Jamaica jet many years ago and while cruising
>>>noticed large reddish flames from the exhaust of the Rolls Royce engine.
>>>How "normal" would that be?
>>>
>>>
>>It depends on the exact conditions. Were you cruising? Climbing?
>>Descending? What altitude? How did the engine sound? How long did the
>>flames last, and what did they look like, exactly?
>>
>>
>
>Under which of these conditions, exactly, would large reddish flames from the
>exhaust of a Rolls Royce engine be 'normal'?
>
>
>
>
>>Normally visible flames don't extend beyond the engine, although if you look
>>directly into the exhaust of a jet engine you may well be able to see glowing
>>internal parts.
>>
>>
>
>That's rather difficult to do from inside the plane.
>
>
>
>
>>High-performance engines may glow externally as well. And of
>>course afterburners can produce long flames that extend well beyond the
>>engine. And so on.
>>
>>
>
>Does Air Jamaica use afterburners?
>
>
>

--
Joe Leikhim K4SAT
"The RFI-EMI-GUY"©

"Treason doth never prosper: what's the reason?
For if it prosper, none dare call it treason."

"Follow The Money" ;-P

[EridanMan]

On Mar 14, 3:59 pm, Dave > wrote:
> Soooo..
>
> How come he (MX) was able to give a rather complete and correct
> answer to the poster's question?
>
> Care to give it a try?
>
> Dave
>
> On Tue, 13 Mar 2007 22:44:15 -0700, C J Campbell
>
> > wrote:
> >On 2007-03-13 17:43:50 -0700, megaMAX
> > said:
>
> >> On Wed, 14 Mar 2007 01:18:33 +0100, Mxsmanic >
> >> wrote:
>
> >>> Most commercial flights are flown on autopilot for the vast majority of the
> >>> trip. Thus you would have seen autopilot corrections, not pilot corrections.
>
> >Just so you know, Msxmanic does not know any more about flight than you
> >do. He is not a pilot. He is just some nut who hangs out here and
> >pretends to know what he is talking about.

MX's knowledge is very sophomoric, and heavily stilted towards biases
introduced by inaccuracies in his simulations.

As in this case.

Minor Harmonic oscillations in flights are a natural byproduct of the
dynamic stability of modern aircraft. The Autopilot has no part in
it.

When the oscillations are on the Longitudinal axis, they are called
phugoid oscillations, I'm not sure if there is a similar term for the
roll equivolents, but it is the same deal- Essentially what is
happening is a battle between the aircraft's substantial momentum, and
the aerodynamic forces which keep it pointed into the wind... Large
out-of-trim deflections (both roll and pitch) are damped quickly, but
there is a threshold at which the amplitude of the oscillations falls
below the aerodynamics ability to produce large enough forces to damp
the behavior...

The period and amplitude of these harmonic functions are directly
related to the configuration and chord of the aerodynamic surfaces vs.
The aircraft's distribution of mass. In general, thinner aerodynamic
surfaces create stronger off-center aerodynamic forces and hence
better damping, and lighter aircraft produce weaker momentum forces
and again, fewer oscillations. Granted, 'fewer' in this case is a
matter of perception... the oscillations you were seeing were really
very minor (less than a degree), its just that the solid horizon
combined with the long arm of the wing made them more obvious than the
same fraction of a degree roll oscillation would be in a smaller
aircraft.

No MX... it has nothing to do with the autopilot...

FWIW, I remember reading somewhere that the 747 prototype actually had
a problem on its first few flights - the engineers had designed the
aerodynamic surfaces to damp the phugoid (longitudinal) harmonics
based on a theoretical perfectly rigid aircraft, however, in reality,
it turned out that the fuselage had a natural bending resonance
frequency which matched the aerodynamic harmonic frequency, and they
amplified eachother to produce an in flight longitudinal harmonic that
was actually quite substantial... the result, IIRC, was a very sick
planeload of journalists on the aircraft's first publicity flight.

For more information, read up on both Phugoid oscillations and Roll
stability via using wing dihedral.

[EridanMan]

On Mar 15, 12:14 pm, Mxsmanic > wrote:
> writes:
> > Yes, they can.
>
> No, they cannot, except under ideal conditions, and sometimes not even then.

They do not have too. They only need to get the aircraft close enough
for wing dihedral to do the rest. Its called a dynamically stable
aircraft design, and its been a cornerstone of aviation almost since
its inception.

> > But what do I know, I only fly tiny planes.
>
> My thoughts exactly.

That's funny, by your theory, stable flight was impossible until the
mid-80s...

[EridanMan]

> Correction: Actually, Mxsmanic knows a great deal, _despite_ not being a
> pilot.

I cannot disagree with this.

The problem is that you do not know what you do not know, and lack of
practical experience has left your knowledge with a great number of
holes that you refuse to acknowledge.

It is a typically sophomoric attitude (hence my initial impression
that you were an adolescent).

> This is particularly true with respect to large aircraft, since most
> of the pilots here are familiar only with the tiny aircraft they fly, whereas
> he has studied both small and large aircraft.

That is a GROSS generalization.

Yes, some pilot's only care about the planes that they fly... I would
say that is actually the exception rather than the rule, however.

The rest of us have just as much a passion for aviation as yourself
AND we fly. When we're not spending our spare time in a cockpit, we
spend it learning about aircraft and aircraft systems... Aircraft
design (A particular favorite topic of mine) and other aviation
related topics... and hell, even flying sims...

> More to the point: If you see an error in anything I've said, feel free to
> point it out.

Your explanation of the cause of the roll oscillations was utterly
wrong, and your desire to attribute ultimate aircraft stability to
autopilot design is also largly incorrect (Except in a few isolated
(almost always military) cases of relaxed stability aircraft.

> He doesn't have to pretend.

This might be a low blow but...

Isn't that the fundamental definition of Simulation?;)

> Nor is he so insecure that he must engage in personal attacks if someone else seems to know more.

I actually agree that the personal attacks against you have grown more
disruptive than your actual sophomoric nature.

One of the aggravations I have had, however - is you do not seem to
respond to anything BUT the personal attacks - I have seen MANY
knowledgeable, polite corrections and responses to your assertions go
un-heeded while you chose only to argue with those who attacked you.
It gives the impression that you seek the negative attention over
actual helpfulness.

I still wish you'd take some time to get your information from sources
OTHER than public forums however... So many of your questions could be
answered so much easier and faster via a quick Google search.

And It would also be nice if you added an occasional "my understanding
is" disclaimer to some of your more authoritative-toned posts...

[C J Campbell[_1_]]

On 2007-03-14 15:59:45 -0700, Dave > said:

> Soooo..
>
> How come he (MX) was able to give a rather complete and correct
> answer to the poster's question?
>
> Care to give it a try?
>
> Dave

The fact that he is right once in awhile is no indication that he knows
what he is talking about. He is not a pilot. He is a flight-sim guy.
Even Mxs should be able to learn something. But what he says should in
no way be considered reliable.

--
Waddling Eagle
World Famous Flight Instructor

[Dave[_3_]]

Understood, and we agree...

But he is right some of the time, along with many others here..

There are also a couple of other guys I know of who could answer
this question, probably better than anyone here....

One is a designer of autopilots, the other is an aeronautical
engineer....

.....neither is a pilot, nor has any interest in becoming one...

So, I guess many here would chastise them if they posted their
opinions here, because they are not "pilots"...

But, I guess that all works out, because Bombardier PAYS THEM BOTH
VERY WELL for their thoughts/opinions/ideas.

But, alas, like MX, they are not pilots.. :(

D



On Thu, 15 Mar 2007 18:43:25 -0700, C J Campbell
> wrote:

>On 2007-03-14 15:59:45 -0700, Dave > said:
>
>> Soooo..
>>
>> How come he (MX) was able to give a rather complete and correct
>> answer to the poster's question?
>>
>> Care to give it a try?
>>
>> Dave
>
>The fact that he is right once in awhile is no indication that he knows
>what he is talking about. He is not a pilot. He is a flight-sim guy.
>Even Mxs should be able to learn something. But what he says should in
>no way be considered reliable.

[Mxsmanic]

EridanMan writes:

> The problem is that you do not know what you do not know ...

A greater problem is that a lot of pilots here don't know, either, although
many think that they know it all once they have a license (and that,
conversely, anyone without one knows nothing). The truth is considerably less
extreme.

> ... and lack of
> practical experience has left your knowledge with a great number of
> holes that you refuse to acknowledge.

The "holes" pointed out to me consist almost exclusively of physical
sensations of flying. The mistake made by pilots here is to think that these
sensations are 99% of flying, when in fact their importance varies with the
type of flying under consideration.

This is a consequence of many pilots here being tin-can, seat-of-the-pants
pilots, with little or no experience or knowledge of other types of aircraft.
They see everything from the cockpit of a Cessna, and they think that's all
there is.

> That is a GROSS generalization.

It's also a very accurate one. It's painfully obvious that many of the pilots
here are low-time, small-aircraft pilots. Everything they say reflects this
viewpoint.

> Yes, some pilot's only care about the planes that they fly... I would
> say that is actually the exception rather than the rule, however.

Most of them only _know_ about the plane(s) they fly. They don't know about
other planes, so they don't care about them.

They think that knowing the fine details of control pressures in a Cessna is
vitally important, but when I point out that many large aircraft don't work
this way at all, they dismiss that as unimportant. But it's not unimportant
to an Airbus pilot.

> The rest of us have just as much a passion for aviation as yourself
> AND we fly.

Some people have resources, and others don't.

> When we're not spending our spare time in a cockpit, we
> spend it learning about aircraft and aircraft systems... Aircraft
> design (A particular favorite topic of mine) and other aviation
> related topics... and hell, even flying sims...

Some do, some don't. Some stop half-way and then pretend about the rest.

> Your explanation of the cause of the roll oscillations was utterly
> wrong ...

Provide the correct explanation, then.

> ... and your desire to attribute ultimate aircraft stability to
> autopilot design is also largly incorrect (Except in a few isolated
> (almost always military) cases of relaxed stability aircraft.

See above.

> This might be a low blow but...
>
> Isn't that the fundamental definition of Simulation?;)

Not really. Pretending depends on imagination alone. Simulation removes part
of the need for imagination, so simulation is much less pretending than
non-simulation.

> One of the aggravations I have had, however - is you do not seem to
> respond to anything BUT the personal attacks ...

Many posts contain nothing else, and in fact I let most personal attacks drop,
as they are unrelated to the discussion at hand. It's hard to get people to
discuss the topic, rather than me.

This post is a case in point. You say I was wrong, but you provide no further
information and no corrections, which I find odd. You spend the rest of the
post talking about me, rather than the topic at hand.

> I have seen MANY knowledgeable, polite corrections and responses to
> your assertions go un-heeded while you chose only to argue with those
> who attacked you.

The fact that I do not reply to a post doesn't mean that I haven't read it or
understood it. It usually just means that I have no quarrel with it and no
further questions about it.

Those who engage in personal attacks also tend to be those who give wrong
answers or incomplete answers or no answers, and so I press them for answers.
People who are aggressive in this way are often being defensive because they
know that their opinions were adopted wholesale from someone else and are
fundamentally baseless. I press them for answers in order to compel them to
look at their opinions and decide whether they are really worth clinging to
when they cannot be substantiated. I consider this a public service.

> It gives the impression that you seek the negative attention over
> actual helpfulness.

I'm not worried about the impression I create. I've found that people have an
enormous tendency to believe what they want to believe, and it's an exercise
in futility to try to make them think more critically. But I try to err on
the side of optimism and so I still do the above.

> I still wish you'd take some time to get your information from sources
> OTHER than public forums however ...

Most of my information comes from other sources, since it is hard to find
people here who actually know what they are talking about. USENET is just one
of many sources.

> So many of your questions could be
> answered so much easier and faster via a quick Google search.

I do Google searches regularly, although I don't have as much faith in them as
you might.

> And It would also be nice if you added an occasional "my understanding
> is" disclaimer to some of your more authoritative-toned posts...

Why? To spare the overinflated egos of a minority? Why would I say something
that is _not_ my understanding? How could anything I say (or anything anyone
else says) be anything _other_ than an understanding?

--
Transpose mxsmanic and gmail to reach me by e-mail.

[Mxsmanic]

EridanMan writes:

> They do not have too. They only need to get the aircraft close enough
> for wing dihedral to do the rest. Its called a dynamically stable
> aircraft design, and its been a cornerstone of aviation almost since
> its inception.

Until Airbus came along.

--
Transpose mxsmanic and gmail to reach me by e-mail.

[Mxsmanic]

EridanMan writes:

> Minor Harmonic oscillations in flights are a natural byproduct of the
> dynamic stability of modern aircraft. The Autopilot has no part in
> it.

Do these oscillations cause control surfaces to move by themselves? Are they
asymmetrical?

> When the oscillations are on the Longitudinal axis, they are called
> phugoid oscillations, I'm not sure if there is a similar term for the
> roll equivolents ...

Dutch roll and spiral come to mind, although they are not limited exclusively
to the roll axis.

> No MX... it has nothing to do with the autopilot...

If the control surfaces are moving, either the pilot or the autopilot is
acting upon them. If the corrections are asymmetrical, this would tend to
exclude the hypothesis of harmonic oscillations. Also, roll harmonics often
extend over periods of minutes in large aircraft and would not be obvious just
by watching the wing outside the window.

--
Transpose mxsmanic and gmail to reach me by e-mail.

[Mxsmanic]

C J Campbell writes:

> The fact that he is right once in awhile is no indication that he knows
> what he is talking about.

He is right more than just once in a while, and it is self-evident that if he
is right, he knows what he is talking about, since the chance of a random
answer being correct is exceedingly small.

> He is not a pilot. He is a flight-sim guy.

That's the part that irritates you. Unfortunately, it has almost nothing to
do with knowing what one is talking about, despite a widespread misconception
to the contrary. Another example of credentialism. People who cannot depend
on an unambiguous distinction between knowledge and ignorance resort to
credentialism to maintain artificial separations.

> Even Mxs should be able to learn something. But what he says should in
> no way be considered reliable.

Exactly the same can be said of pilots.

--
Transpose mxsmanic and gmail to reach me by e-mail.

[Mxsmanic]

Dave writes:

> There are also a couple of other guys I know of who could answer
> this question, probably better than anyone here....
>
> One is a designer of autopilots, the other is an aeronautical
> engineer....
>
> ....neither is a pilot, nor has any interest in becoming one...
>
> So, I guess many here would chastise them if they posted their
> opinions here, because they are not "pilots"...

No doubt. There are many specialties in aviation, but I note that pilots seem
unusually prone to believe that they know _everything_ about aviation, even
though that is manifestly impossible, and even though, in fact, pilots only
learn what they need to know to fly (which is only a tiny part of aviation
knowledge).

On some occasions, I've had a terrible time convincing pilots that 90-degree
banks are impossible in coordinated turns, or that all turns involve
continuous lateral accelerations.

Many people learn what they know by rote, since this is much easier than
learning theory and inductively reasoning forward to specific knowledge.
Those who learn by rote don't realize that their learning is only one
interpretation of an underlying theory, and other interpretations are just as
valid.

Examples I've seen here are arguments about neutral trim and the way trim
works, or stall speeds.

I try to learn the theory when I can (except when it gets heavy into math--I
hate math). Theory leaves you better equipped to handle the unexpected than
rote learning does.

> But, I guess that all works out, because Bombardier PAYS THEM BOTH
> VERY WELL for their thoughts/opinions/ideas.
>
> But, alas, like MX, they are not pilots..

So they are rich, but they can't climb into the treehouse. I daresay that
does not upset them.

--
Transpose mxsmanic and gmail to reach me by e-mail.

[TheSmokingGnu]

A rarity! My killfile must have bitten the dust with last reformat. Alas.

Mxsmanic wrote:
> The mistake made by pilots here is to think that these
> sensations are 99% of flying, when in fact their importance varies with the
> type of flying under consideration.

The counter-example being, of course, that even high-time regular
heavy-iron pilots find the loss of feeling in the control column in
modern fly-by-wire aircraft so disruptive and unnerving that the
engineers had to design systems to emulate them, leading someone more
prone to contemplation to perhaps consider kinesthetics more important
than not.

> They see everything from the cockpit of a Cessna...

Whereas, one points out, you have not even seen that.


> It's painfully obvious that many of the pilots
> here are low-time, small-aircraft pilots. Everything they say reflects this
> viewpoint.

Why say that? Provide some examples, lest you fall into your own trap of
incompleteness in objective.

> Most of them only _know_ about the plane(s) they fly. They don't know about
> other planes, so they don't care about them.

Perhaps, again, that other pilots in the group actually do know little
of the specific aircraft, and choose to refrain from making
pronouncements and edicts of procedure and performance, based on the
knowledge of their ignorance, instead of barging into threads where they
would only succeed in mucking things up with incorrect information and
speculation.

> They think that knowing the fine details of control pressures in a Cessna is
> vitally important, but when I point out that many large aircraft don't work
> this way at all, they dismiss that as unimportant. But it's not unimportant
> to an Airbus pilot.

See the first above.

> Some people have resources, and others don't.

Some understand how to live within their means while enjoying their
passion, and others simply look in from the outside and stir the pot in
the hopes of becoming a part of the community.

> Some do, some don't. Some stop half-way and then pretend about the rest.

And yet others pretend about it all.

> Provide the correct explanation, then.

Provided by other posters, which that hypothetical contemplatieur would
note you have not chosen to respond to, and that is: positive stability
brought on by wing dihedral (which, one also notes, is a feature of BOTH
Boeing and Airbus wings: why make an active system to compensate for
what can be designed out with passive engineering?).

> Simulation removes part
> of the need for imagination, so simulation is much less pretending than
> non-simulation.

Simulation allows for the so-called "suspension of disbelief", which
necessarily denotes that the participant recognizes and properly
attributes the qualities and failings of such "simulation" in the first
place.

---

Here we part with the third person (which, noted, you enjoy referring to
yourself with).

>> I have seen MANY knowledgeable, polite corrections and responses to
>> your assertions go un-heeded while you chose only to argue with those
>> who attacked you.
>
> The fact that I do not reply to a post doesn't mean that I haven't read it or
> understood it. It usually just means that I have no quarrel with it and no
> further questions about it.

Netiquette demands at least a thank-you or acknowledgment of receipt.

>
> Those who engage in personal attacks also tend to be those who give wrong
> answers or incomplete answers or no answers, and so I press them for answers.
> I press them for answers in order to compel them to
> look at their opinions and decide whether they are really worth clinging to
> when they cannot be substantiated. I consider this a public service.

Translation: I assault posters with incessant questions, even about
objective, immutable topics, in order to frustrate further conversation
or to provide some tangible ethical or moral response to which I can
cling and make incorrect, hurtful, baseless assertions. I consider
myself superior over all others, even those with a clearly higher
understand or better experience.

> I've found that people have an
> enormous tendency to believe what they want to believe, and it's an exercise
> in futility to try to make them think more critically.

Found a mirror again?

> Most of my information comes from other sources...

Of which you refuse to enumerate when issued questions or inquiry (which
inevitably leads to doubt of veracity).

> Why? To spare the overinflated egos of a minority? Why would I say something
> that is _not_ my understanding? How could anything I say (or anything anyone
> else says) be anything _other_ than an understanding?

No, to spare the uninitiated of misplaced trust.

You fail to understand the difference between understanding and
knowledge (used in this vernacular). There is a fundamental dichotomy
between third-party repetition of information, and a statement of fact.
Even you must recognize that much of your writing comes off as though
you have real, first-party knowledge of a topic, when in truth you are
either re-stating another's or your own interpretation of subjective fact.

Thus, again casting doubt on your actual capability, which is not
assisted by your utter rigidity (or, colloquially, Ferrous Cranus).

http://redwing.hutman.net/~mreed/warriorshtm/ferouscranus.htm

TheSmokingGnu

[Mxsmanic]

TheSmokingGnu writes:

> The counter-example being, of course, that even high-time regular
> heavy-iron pilots find the loss of feeling in the control column in
> modern fly-by-wire aircraft so disruptive and unnerving that the
> engineers had to design systems to emulate them, leading someone more
> prone to contemplation to perhaps consider kinesthetics more important
> than not.

Except that this isn't true. Feel and feedback are not hugely important and
one can easily become used to their absence. Simulating them in a large
aircraft is mostly a matter of convenience for pilots--not necessity. Indeed,
since the "feel" varies greatly from one aircraft to another, irrespective of
whether or not it is real or simulated, the habituation to control feel isn't
very transferable.

> Whereas, one points out, you have not even seen that.

It's only a tiny dot on the aviation landscape, and I don't consider it
important. Most pilots have never seen anything from most cockpits. That
isn't much of a handicap.

> Why say that?

Because it's true.

> Provide some examples, lest you fall into your own trap of
> incompleteness in objective.

The obsessions with sensation and control feel, issues that are highly
specific to certain types of aviation (such as small aircraft). The
preoccupation with VFR and VMC over IFR and IMC. The cluelessness with
respect to complex avionics and navigation systems. The acceptance of engine
failures as an unavoidable fact of life (most airline pilots go through their
entire careers without ever seeing an engine failure). And so on.

> Perhaps, again, that other pilots in the group actually do know little
> of the specific aircraft, and choose to refrain from making
> pronouncements and edicts of procedure and performance, based on the
> knowledge of their ignorance, instead of barging into threads where they
> would only succeed in mucking things up with incorrect information and
> speculation.

Nothing prevents them from studying to reduce their ignorance.

> See the first above.

See an Airbus.

> Some understand how to live within their means while enjoying their
> passion, and others simply look in from the outside and stir the pot in
> the hopes of becoming a part of the community.

Some people have resources, and some don't. And enjoying a passion doesn't
necessarily have anything to do with joining a "community" (boys' club).

> And yet others pretend about it all.

So I've noticed, but that is their prerogative.

> Provided by other posters, which that hypothetical contemplatieur would
> note you have not chosen to respond to, and that is: positive stability
> brought on by wing dihedral (which, one also notes, is a feature of BOTH
> Boeing and Airbus wings: why make an active system to compensate for
> what can be designed out with passive engineering?).

The reason for using an active system is that it improves maneuverability.
The drawback is that the aircraft has a tendency to depart from controlled
flight if the computers fail. That's Airbus. It's not Boeing (as far as I
know, with respect to civilian aircraft).

> Here we part with the third person (which, noted, you enjoy referring to
> yourself with).

No, I was simply continuing the style of the posts to which I responded, to
reduce ambiguity.

> Netiquette demands at least a thank-you or acknowledgment of receipt.

Netiquette is an illusion. And in any case, I'm not interested in courtesy
rituals. Those who require the ego boost of some expression of gratitude need
not reply. Sharing knowledge should be its own reward.

> Translation: I assault posters with incessant questions, even about
> objective, immutable topics, in order to frustrate further conversation
> or to provide some tangible ethical or moral response to which I can
> cling and make incorrect, hurtful, baseless assertions. I consider
> myself superior over all others, even those with a clearly higher
> understand or better experience.

No. That is the perception that some have of it, but they allow their
emotions to rule, which is a bad thing in itself. People who are slaves to
their emotions are highly vulnerable and easy to manipulate. It's not good to
have large segments of the population with this handicap.

> Of which you refuse to enumerate when issued questions or inquiry (which
> inevitably leads to doubt of veracity).

There is no need to enumerate them. Others can do their own research and
learn for themselves whether or not I'm right. It's surprising how rarely
they do this.

> No, to spare the uninitiated of misplaced trust.

Why would anyone trust a name on a screen?

> You fail to understand the difference between understanding and
> knowledge (used in this vernacular).

Which vernacular?

> There is a fundamental dichotomy between third-party repetition
> of information, and a statement of fact.

No, they are independent.

> Even you must recognize that much of your writing comes off as though
> you have real, first-party knowledge of a topic, when in truth you are
> either re-stating another's or your own interpretation of subjective fact.

I leave verification as an exercise for the reader. And if I seem to have
real, first-party knowledge of a topic, that may well be correlated with the
fact that I am often right.

--
Transpose mxsmanic and gmail to reach me by e-mail.

[TheSmokingGnu]

Mxsmanic wrote:
> Except that this isn't true.

Do deny that airliners are fitted with artificial feel systems?

> Because it's true.

Why?

> The obsessions with sensation and control feel, issues that are highly
> specific to certain types of aviation (such as small aircraft). The
> preoccupation with VFR and VMC over IFR and IMC. The cluelessness with
> respect to complex avionics and navigation systems. The acceptance of engine
> failures as an unavoidable fact of life (most airline pilots go through their
> entire careers without ever seeing an engine failure). And so on.

I still fail to see the specific examples I requested, but rather your
opinions and interpretations instead.

Also, do you feel that engine failures are such a rare occurrence that
they should be deprioritized in training and emergency procedure
(keeping in mind that vast number of reasons that an engine might fail)?

> Nothing prevents them from studying to reduce their ignorance.

Ah, but even then they would have to say that they have merely studied
the surface issues, and still yet have no direct experience.

> See an Airbus.

Seen, noted, observed wing dihedral, question remains unanswered.

> So I've noticed, but that is their prerogative.

Ah, so you DO re-read your posts?

> The reason for using an active system is that it improves maneuverability.
> The drawback is that the aircraft has a tendency to depart from controlled
> flight if the computers fail. That's Airbus. It's not Boeing (as far as I
> know, with respect to civilian aircraft).

What maneuverability would be required? Certain posters here would have
us believe that civilian jets are hardly capable of the turns they make,
let alone any kind of extreme evasion; more to the point, why design
systems that fail catastrophically? Why not use a passive design that
cannot fail in any kind of practical sense, and which always returns to
center?

> Sharing knowledge should be its own reward.

Can we list the antithesis, that suffering speculation is its own torture?

> There is no need to enumerate them. Others can do their own research and
> learn for themselves whether or not I'm right.

You could at least do the courtesy of leading them in the right
direction, since you consider this a service to the public. The listing
of sources is a time-honored tradition in any kind of academic or
educational capacity (to wit: theses, or indeed any kind of research
paper); I don't expect formal formatting, but even an informal list,
perhaps?

> Why would anyone trust a name on a screen?

Why would anyone trust words on a page?

> Which vernacular?

The one to which I was referring, within the present context, with
accompanying explanation and dissertation.

> No, they are independent.

You /ARE/ familiar with the term "dichotomy", correct?

> I leave verification as an exercise for the reader. And if I seem to have
> real, first-party knowledge of a topic, that may well be correlated with the
> fact that I am often right.

See the above RE: sources. If you have practical first-hand experience,
by all means validate your evocations with a qualifier, so that people
(again, your deserving public) may more readily distinguish between
research and anecdote.

TheSmokingGnu

[Ron Natalie]

Mxsmanic wrote:
> EridanMan writes:
>
>> They do not have too. They only need to get the aircraft close enough
>> for wing dihedral to do the rest. Its called a dynamically stable
>> aircraft design, and its been a cornerstone of aviation almost since
>> its inception.
>
> Until Airbus came along.
>
Your pathetic ignorance continues to show. This one isn't even
related to your continual fantasy land.

Despite all the flight control systems in the fly-by-wire airbuses,
they still have positive stability. Now Boeing on the other hand
thought the 767 at first wasn't going to have positive pitch stability.
They spent a lot of time working with GE to develop active components
to control that. Fortunately as the design progressed it turned out
to not be necessary.

Further, it's not just fly by wire aircraft that have artificial
feel built in to them. Yes, in the case of FBW it's 100% artificial
but don't believe that a lot of time isn't spent on many aircraft to
get the control forces to feel right.

[Ron Natalie]

Mxsmanic wrote:
> EridanMan writes:
>
>> Minor Harmonic oscillations in flights are a natural byproduct of the
>> dynamic stability of modern aircraft. The Autopilot has no part in
>> it.
>
> Do these oscillations cause control surfaces to move by themselves? Are they
> asymmetrical?

Sometimes, and yes.

> Dutch roll and spiral come to mind, although they are not limited exclusively
> to the roll axis.

Spiral is not an oscillation. Spiral is a departure from positive
stability when you push things too far.

If you get behind the yoke of a real aircraft, get it all trimmed up and
take your hands off (NO AUTOPILOT) and then shove hard on the yoke and
let go, you'll see either one of two things. It will either oscillate
back and forth through the trimmed flight eventually settling down or
it will very slowly return to trimmed flight by just bringing the nose
up.

>
>> No MX... it has nothing to do with the autopilot...
>
> If the control surfaces are moving, either the pilot or the autopilot is
> acting upon them.

Absolutely and totally incorrect. You should go read a introductory
pilots book section on flight aerodynamics.

> If the corrections are asymmetrical, this would tend to
> exclude the hypothesis of harmonic oscillations. Also, roll harmonics often
> extend over periods of minutes in large aircraft and would not be obvious just
> by watching the wing outside the window.

Now your an aerodynamics expert?

[Ron Natalie]

Mxsmanic wrote:

> No doubt. There are many specialties in aviation, but I note that pilots seem
> unusually prone to believe that they know _everything_ about aviation, even
> though that is manifestly impossible, and even though, in fact, pilots only
> learn what they need to know to fly (which is only a tiny part of aviation
> knowledge).

And you profess to know everything even though you fly nothing.

> On some occasions, I've had a terrible time convincing pilots that 90-degree
> banks are impossible in coordinated turns, or that all turns involve
> continuous lateral accelerations.

Of course you'll have a terrible time convincing people of that.

All coordinated flight involves is that the tail of the aircraft follow
the front in the flight path (this is confusing to most people primarily
because of the FAA's stupid pseudo-physics definition of it). There
is nothing that prevents coordinated 90 degree banks. In most aircraft
however, you're not going to be able to sustain that. Since you've
lost your primary lift source (the wings) because they now have their
lift vector perpendicular to vertical, to maintain altitude, you need
to get a little lift form unconventional places. This is usually done
by canting the fuselage a little bit. This almost always involves
a bit of non-coordination.

The secret of turning is not just that there is a lateral acceleration
(if that is all there was, you'd just start translating towards the
banked side rather than turning) but that the direction of that
acceleration is continuously changed .

> I try to learn the theory when I can (except when it gets heavy into math--I
> hate math). Theory leaves you better equipped to handle the unexpected than
> rote learning does.

Then why do you fail to understand it very well/>?

[[email protected]]

On Mar 15, 8:14 pm, Mxsmanic > wrote:
> writes:
> > Yes, they can.
>
> No, they cannot, except under ideal conditions, and sometimes not even then.
>
> > But what do I know, I only fly tiny planes.
>
> My thoughts exactly.
>
> --
> Transpose mxsmanic and gmail to reach me by e-mail.

Well, this tiny-plane-pilot can and have done so, and there are many
others.
Not that I liked it though.

-Kees

[Mxsmanic]

TheSmokingGnu writes:

> Do deny that airliners are fitted with artificial feel systems?

Some are. But feel varies significantly from one aircraft to another.
Sometimes it is simulated just because pilots expect it.

> Why?

I don't know why it's true.

> Also, do you feel that engine failures are such a rare occurrence that
> they should be deprioritized in training and emergency procedure
> (keeping in mind that vast number of reasons that an engine might fail)?

I think they should be kept in perspective. Engine failures in certain phases
of flight are serious emergencies, and since they are so easy to practice in
simulation, there's not much reason not to do so. But at the same time, they
are extremely rare in large commercial airliners, so practicing them in excess
(to the detriment of practice in other, more likely emergency scnearios) is
probably not a good idea.

In small aircraft, the engines are so unreliable that engine failures must be
practiced. Ironically, there's no really good way to practice them, since
full-motion simulators for small aircraft are rare, and it's too dangerous to
practice true engine failures in a real aircraft (setting an engine to idle
doesn't count).

> Ah, but even then they would have to say that they have merely studied
> the surface issues, and still yet have no direct experience.

There isn't any specific limit to the depth of study one can undertake. Both
study and experience are legitimate ways to learn; both can lead one to attain
the same goals.

> Seen, noted, observed wing dihedral, question remains unanswered.

Some Airbus aircraft are designed to be unstable, under the assumption that
computers will keep them flying straight and level.

> What maneuverability would be required?

That's a good question. You'd have to ask Airbus. I can't think of any high
maneuverability requirements for airliners.

> Certain posters here would have
> us believe that civilian jets are hardly capable of the turns they make,
> let alone any kind of extreme evasion ...

They are capable of much more than is usually requested of them. This being
so, going beyond that seems illogical. But I've never seen much logic in
Airbus--after all, it's a political organization.

> ... why design systems that fail catastrophically?

Systems fail catastrophically when they are _not_ designed. Catastrophic
failure modes are characteristic of unanticipated exceptions in digital
systems.

> Why not use a passive design that cannot fail in any kind of practical
> sense, and which always returns to center?

That cannot be done with digital systems. They only fail safe in modes that
are anticipated in the design; in other modes, catastrophic failure is more
likely.

> You could at least do the courtesy of leading them in the right
> direction, since you consider this a service to the public.

That would not be verification.

> The listing of sources is a time-honored tradition in any kind of academic or
> educational capacity

Yes, and it is vastly overrated in consequence. Many incorrectly assume that
the mere presence of references somehow validates whatever uses them.

> Why would anyone trust words on a page?

Exactly.

> You /ARE/ familiar with the term "dichotomy", correct?

Yes. And I don't even need to look it up. Your use of the term puzzled me,
but it was part of a pattern I noticed in the entire post, so I let it slide.

> See the above RE: sources. If you have practical first-hand experience,
> by all means validate your evocations with a qualifier, so that people
> (again, your deserving public) may more readily distinguish between
> research and anecdote.

They need to do their own research.

--
Transpose mxsmanic and gmail to reach me by e-mail.

[Mxsmanic]

Ron Natalie writes:

> Sometimes, and yes.

What makes them asymmetrical?

> Spiral is not an oscillation. Spiral is a departure from positive
> stability when you push things too far.

Spiral instability.

> Absolutely and totally incorrect.

It depends on the aircraft, but my generalization is mostly valid.

> You should go read a introductory
> pilots book section on flight aerodynamics.

That's the problem with pilots' books: they never go past the introduction to
these complex topics.

> Now your an aerodynamics expert?

I've never claimed to be an expert. But I do know something about it.
Asserting or sharing knowledge is not a claim of expertise.

--
Transpose mxsmanic and gmail to reach me by e-mail.

[Mxsmanic]

Ron Natalie writes:

> And you profess to know everything even though you fly nothing.

I have never claimed to know everything. I don't need to fly to know things.

> Of course you'll have a terrible time convincing people of that.

Not if they understand the theory, which many pilots do not.

> All coordinated flight involves is that the tail of the aircraft follow
> the front in the flight path (this is confusing to most people primarily
> because of the FAA's stupid pseudo-physics definition of it).

Coordinated turns maintain an acceleration vector parallel to the yaw axis.
It is impossible to do this in a 90-degree bank. There is always a vertical
component produced by gravity, and this means the acceleration vector can
never be completely horizontal, and yet it would have to be in a 90-degree
bank for a coordinated turn. The horizontal component would have to be of
infinite magnitude, which is not possible.

> There
> is nothing that prevents coordinated 90 degree banks. In most aircraft
> however, you're not going to be able to sustain that.

You cannot achieve it in any aircraft, much less sustain it.

--
Transpose mxsmanic and gmail to reach me by e-mail.

[Jim Stewart]

> In small aircraft, the engines are so unreliable that engine failures must be
> practiced. Ironically, there's no really good way to practice them, since
> full-motion simulators for small aircraft are rare, and it's too dangerous to
> practice true engine failures in a real aircraft (setting an engine to idle
> doesn't count).

Loon mallet please....

[TheSmokingGnu]

Mxsmanic wrote:
> Sometimes it is simulated just because pilots expect it.

So you admit that in expecting it, the pilots must necessarily feel it
(or rather, expect to feel it; want to feel it; know that they should
feel it; know that it should exist).

> I don't know why it's true.

Then how can you say that it is not false?

> But at the same time, they
> are extremely rare in large commercial airliners, so practicing them in excess
> (to the detriment of practice in other, more likely emergency scnearios) is
> probably not a good idea.
>
> In small aircraft, the engines are so unreliable that engine failures must be
> practiced.

Surface analysis of the NTSB database would seem to mete this out; last
year there were just 2 incidents in jets, while general aviation racked
up 25. However, without a more detailed report of accidents per flight
or per mile (or per capita), I would be hesitant to make such claims
with authority.

Ironically, more of the GA accidents with fatalities occurred in large
turbine/heavy twin aircraft, while small "tin-cans" were generally
non-fatal if not merely incidental.


>(setting an engine to idle
> doesn't count).

Why not, if the purpose of the practice is to experience a loss of
meaningful power and to execute the proper diagnostics to the engine as
well as the correct emergency procedures? Idling the engine would seem
to be a perfect solution.

> Some Airbus aircraft are designed to be unstable, under the assumption that
> computers will keep them flying straight and level.

Which?

>> ... why design systems that fail catastrophically?
>
> Systems fail catastrophically when they are _not_ designed. Catastrophic
> failure modes are characteristic of unanticipated exceptions in digital
> systems.

Surely an engineer would anticipate the failure of a computer system.
Heck, that's why we have triple-redundancy hydraulic systems (with
backup electrics, no less).

That same engineer would also surely see that using an active control
system (with a failure potential) is inferior to using plain old physics
(which has already been demonstrated on many other designs; why try to
fix what isn't broken)?

> That cannot be done with digital systems. They only fail safe in modes that
> are anticipated in the design; in other modes, catastrophic failure is more
> likely.

But the system in question here is not digital, nor is it controlled as
such by the fly-by-wire systems. Dihedral in a wing uses physics (and a
helping hand from Mr. Daniel Bernoulli) to roll an aircraft level (or
more towards level), sans control inputs. Why would an engineer ignore
this time-tested approach to wing design in favor of an active (and
potentially failure-prone) system?

> That would not be verification.

But it would start the process.

> Yes, and it is vastly overrated in consequence. Many incorrectly assume that
> the mere presence of references somehow validates whatever uses them.

I think many assume that the presence of references provides a trail of
fact-checking and verification which is important when trying to assert
the validity of analysis and claims made in such academia.

> Your use of the term puzzled me,

I'm not sure why; I used it to indicate two separate concepts, which you
promptly corrected me by saying that they were.... independent.

It would have seemed to the outside viewer that perhaps you had not
understood the usage.

> They need to do their own research.

Hard to do without a platform to stand on from which to begin, eh? It
would hardly be fair if you wanted to verify my claims of why the sky
was blue, but you had to discover the atom first (and then molecules,
dipole bonding forces, light refraction, fusion, astronomy, and various
other sundry basal sciences), right?

Public services usually aim to provide helpful and useful information,
as well as a stepping stone for learning more about the topic, not
commands from on-high from an individual who holds himself in higher
standing than his peers.

TheSmokingGnu

[EridanMan]

> Until Airbus came along.

No... wrong again.

Airbii are statically stable for efficiencies sake, their control
mechanism is irrelevant.

[Mxsmanic]

TheSmokingGnu writes:

> So you admit that in expecting it, the pilots must necessarily feel it
> (or rather, expect to feel it; want to feel it; know that they should
> feel it; know that it should exist).

They want to feel it. They don't need it. It makes pilots comfortable,
especially those who dislike change. It makes them feel as if they are still
in control, even when they are not.

> Then how can you say that it is not false?

I don't have to know why something is true just to know that it's true. I
know that some flowers are blue and others are red--it's definitely true--but
I don't know why.

> Surface analysis of the NTSB database would seem to mete this out; last
> year there were just 2 incidents in jets, while general aviation racked
> up 25. However, without a more detailed report of accidents per flight
> or per mile (or per capita), I would be hesitant to make such claims
> with authority.

The NTSB database is pretty reliable.

> Why not, if the purpose of the practice is to experience a loss of
> meaningful power and to execute the proper diagnostics to the engine as
> well as the correct emergency procedures?

Because an idle engine is not a stopped engine, as anyone who has experienced
an actual failure can attest.

> Idling the engine would seem to be a perfect solution.

No, it just creates a false sense of security.

> Which?

I've forgotten which models; presumably the more recent ones.

> Surely an engineer would anticipate the failure of a computer system.

There are too many possible failure scenarios. Nobody, not even an engineer,
can anticpate them all. The ones that are not anticipated in the design will
generally produce catastrophic failures (in digital systems).

> Heck, that's why we have triple-redundancy hydraulic systems (with
> backup electrics, no less).

Mechanical systems are not digital. The catastrophic failures come from
software.

> That same engineer would also surely see that using an active control
> system (with a failure potential) is inferior to using plain old physics
> (which has already been demonstrated on many other designs; why try to
> fix what isn't broken)?

Sometimes engineers are seduced by the promise of better performance, to the
detriment of safety.

> But the system in question here is not digital, nor is it controlled as
> such by the fly-by-wire systems.

All modern fly-by-wire systems are digitally controlled, because they depend
on digital computers and software.

> Dihedral in a wing uses physics (and a
> helping hand from Mr. Daniel Bernoulli) to roll an aircraft level (or
> more towards level), sans control inputs. Why would an engineer ignore
> this time-tested approach to wing design in favor of an active (and
> potentially failure-prone) system?

To improve performance. The usual reasoning is that prudent design for
default behavior is unnecessary because the computers can fix it all. This is
a very common error in engineering these days, and not just in aviation.

It's a bit like people who never learn to brake properly in wet conditions
because they expect the ABS to do it for them. The day the ABS fails comes as
a big surprise.

> I think many assume that the presence of references provides a trail of
> fact-checking and verification which is important when trying to assert
> the validity of analysis and claims made in such academia.

That trail is useless if nobody follows it, and most people just assume that
the presence of references makes them valid, without checking. In reality,
there is no improvement in reliability just because there are references.

> I'm not sure why; I used it to indicate two separate concepts ...

That's not what dichotomy means.

> It would have seemed to the outside viewer that perhaps you had not
> understood the usage.

That depends on the education of the outside viewer.

> Hard to do without a platform to stand on from which to begin, eh?

Not at all. All research begins that way. That's why people do research.

> It would hardly be fair if you wanted to verify my claims of why the sky
> was blue, but you had to discover the atom first (and then molecules,
> dipole bonding forces, light refraction, fusion, astronomy, and various
> other sundry basal sciences), right?

Why does it have to be "fair"?

> Public services usually aim to provide helpful and useful information,
> as well as a stepping stone for learning more about the topic, not
> commands from on-high from an individual who holds himself in higher
> standing than his peers.

My public service is in forcing people to think, an activity that will benefit
them over the long term.

--
Transpose mxsmanic and gmail to reach me by e-mail.

[TheSmokingGnu]

Mxsmanic wrote:
> TheSmokingGnu writes:
>
>> So you admit that in expecting it, the pilots must necessarily feel it
>> (or rather, expect to feel it; want to feel it; know that they should
>> feel it; know that it should exist).
>
> They want to feel it. They don't need it. It makes pilots comfortable,
> especially those who dislike change. It makes them feel as if they are still
> in control, even when they are not.

So you admit that the feeling does exist, that it has existed in the
past, that the pilots HAVE felt it, and that they have used it as a
kinesthetic aid to understanding their control (or lack thereof) of the
aircraft.

If they spend all their time ignoring feel, why should they need to add
it back when it's removed from the equation? Shouldn't this have made
their jobs easier?

>
>> Then how can you say that it is not false?
>
> I don't have to know why something is true just to know that it's true. I
> know that some flowers are blue and others are red--it's definitely true--but
> I don't know why.

Your example is intrinsic observation, while the topic under discussion
is analytic, which requires evidence and reasoning. Thus, you cannot
intrinsically say that it is true just because you feel or think that it
should be, but must reinforce your hypothesis (as indeed, that is all
that it is, less a law).

> The NTSB database is pretty reliable.

Indeed, but the argument was over taking statistics derived from such
out of context of actual accident rates (and then trying to draw
conclusions).

> Because an idle engine is not a stopped engine, as anyone who has experienced
> an actual failure can attest.

This does nothing, however, to prevent you from performing the correct
emergency procedures, which is the point of the exercise. Besides, an
idle engine is often worse for performance than a properly stopped one
(vis a vis, a feathered prop), so if you practice with and plan for
reduced glide capability, a real emergency should be a piece of cake.

> No, it just creates a false sense of security.

Security in what?

>> Which?
>
> I've forgotten which models; presumably the more recent ones.

Then how can you make this claim?

A380:
http://www.airliners.net/open.file/1174138/M/

A340-600:
http://www.airliners.net/open.file/1186466/M/

A320-211:
http://www.airliners.net/open.file/1189003/M/

Which of these relatively recent models does not use dihedral in its wing?

>
>> Surely an engineer would anticipate the failure of a computer system.
>
> There are too many possible failure scenarios. Nobody, not even an engineer,
> can anticpate them all. The ones that are not anticipated in the design will
> generally produce catastrophic failures (in digital systems).

I think you'll find (or will soon find out) that engineers spend the
VAST amount of their time coming up with failure scenarios and building
programming to mitigate them. The normal operating code is dead simple.

Most computer systems have fail-safe modes (by most I mean any system
which is critical to keep plane A from falling out of sky B), which at
the very least rescind their automatic functions back to the pilots, or
in the case of fly-by-wire computers, carry triple redundancy (AND still
have a "dumb" mode where they operate the control surfaces directly from
stick input, without translation or interpretation).

So, I reiterate, why would an engineer, whom specifically works on
projects such as failure states, fail to design a system that will fail
in an acceptable manner, especially where lives are concerned?

> Mechanical systems are not digital. The catastrophic failures come from
> software.

Catastrophic failure comes from wherever Murphy decides, regardless of
digital or mechanical systems. A 1 may accidentally be a 0 and try to
fly the plane backwards just as surely as a 10 cent cotter pin comes
loose in a hydraulic pump and disables the ailerons. The quest is and
has always been to design systems that will tolerate that kind of
failure (if only to abdicate control to another), and to use as few
moving and/or thinking parts as possible.

Why then, is it feasible that Airbus (and curiously, Airbus alone)
designed a system perfectly counter to this philosophy?

> Sometimes engineers are seduced by the promise of better performance, to the
> detriment of safety.

Would you care to cite any specific examples?

> All modern fly-by-wire systems are digitally controlled, because they depend
> on digital computers and software.

As I said, we're discussing a specific wing design, not the fly-by-wire
system (although the topic has veered). The fly-by-wire doesn't keep the
wings level (although you seem to assert so), but the in-built dihedral
of the wings does.

> To improve performance. The usual reasoning is that prudent design for
> default behavior is unnecessary because the computers can fix it all. This is
> a very common error in engineering these days, and not just in aviation.

Again, I would ask for a more specific example. I think you'll find that
engineers always, ALWAYS use a prudent, proven design over a new one
(that's why airliners are almost exclusively swept-wing, long straight
fuselage, twin under-wing engined, traditional tailed craft; because the
engineers know the design works and that it has favorable flight
characteristics). Computer systems are only used as an aid or
convenience to alleviate the humans operating the system of some tedium
or micromanagement, never as the crutch of normal operation, and they
are certainly not allowed to be the progenitor of catastrophic failures.

> It's a bit like people who never learn to brake properly in wet conditions
> because they expect the ABS to do it for them. The day the ABS fails comes as
> a big surprise.

If the ABS failed prior to the stop, it would be indicated on the
dashboard, and so should be taken in for maintenance (this is not a
failure caused by the computer then, but human negligence or error).

If the ABS fails mid-stop, there isn't much you could do, anyway,
technique or no. Your brain isn't fast enough to react to the change in
brake action, recognize the situation, decide on the proper course of
action, and send signals to your foot in the split-seconds you have
before impact.

In any case, this example does not provide a situation where the
computer system is the crutch of the operation, nor one where the
failure is catastrophic, nor one where the failure is the fault of the
computer system. The brakes are still connected hydraulically to the
pads (and always will be, regardless of the ABS' actions), the failure
did not disable the brake system (and cannot, short of simultaneously
bursting all of the brake hard-lines; an impossibility). The computer
system did not command the stop, nor did it begin the stop, nor has it
disabled any functionality that the driver possessed, before or after
the failure.

Thus, I submit that the example is not applicable.

> That trail is useless if nobody follows it, and most people just assume that
> the presence of references makes them valid, without checking.

That trail is even more useless when it isn't iterated in the first
place. Even if only one person uses it, you have helped that one person
to greater understanding. Even if only one actually checks the
references, doubts what is said, and learns more by it, that number is
still much, much larger than zero, which is the number possible by NOT
providing references.

> That's not what dichotomy means.

http://dictionary.reference.com/search?q=dichotomy

especially:

2. division into two mutually exclusive, opposed, or contradictory
groups: a dichotomy between thought and action.

>> Hard to do without a platform to stand on from which to begin, eh?
>
> Not at all. All research begins that way. That's why people do research.

People wishing to explore the quantum state (for example) don't need to
reperform all research and analysis which led to that point from the
discovery of the electron, and yet that is what you're forcing people to
do when they have no references. They cannot even look at the specific
texts from which you draw your own conclusion, much less discover the
topic and learn more from it. They must either accept your word at its
face or be forced to strike out some lucky Google search. Hardly an
equitable solution.

> Why does it have to be "fair"?

It's a figure of speech, I mean that it is incorrect to provide no basis
for your claims, to refuse to issue reference texts, and then to deride
and belittle others for not doing the research which, if not impossible,
you make very improbable in the first place. It is proper to provide
those you wish to respect you academically (if at all) with a grounding
in your understanding and analysis.

> My public service is in forcing people to think, an activity that will benefit
> them over the long term.

You cannot contemplate facts into being, even Aristotle recognized this
2,000 years ago in the Nicomachean Ethics. Research is done to provide
factual, objective basis from which original analysis and conclusions
can be drawn (which is admittedly what you are trying to do). Academic
peers seek this basis, from which to debate or criticize your viewpoint,
to draw their own conclusions, or to learn more about the topic at hand.
You are denying them this basic academic freedom and obscuring it under
the guise of a service.

TheSmokingGnu

[Mxsmanic]

MXMORON writes:

> Since you haven't tried, how can you know this?

Research.

--
Transpose mxsmanic and gmail to reach me by e-mail.

[Ron Natalie]

Mxsmanic wrote:

>
> Coordinated turns maintain an acceleration vector parallel to the yaw axis.

Not true. In a normal coordinated turn (lets do 45 degrees of bank),
the acceleration vector points towards the inside of the turn. The
yaw axis itself is canted at a 45 degree angle.

> It is impossible to do this in a 90-degree bank. There is always a vertical
> component produced by gravity, and this means the acceleration vector can
> never be completely horizontal, and yet it would have to be in a 90-degree
> bank for a coordinated turn. The horizontal component would have to be of
> infinite magnitude, which is not possible.

Sorry, that's untrue. The acceleration is always horizontal in a level
turn regardless of bank.
>
>> There
>> is nothing that prevents coordinated 90 degree banks. In most aircraft
>> however, you're not going to be able to sustain that.
>
> You cannot achieve it in any aircraft, much less sustain it.
>
That would be news to a lot of acro pilots. The fallacy (in addition
to your other mistakes of physics and aerodynamics) is that the wings
are the only aerodynamic surface in play.

[Ron Natalie]

Mxsmanic wrote:
> Ron Natalie writes:
>
>> Sometimes, and yes.
>
> What makes them asymmetrical?
>
>> Spiral is not an oscillation. Spiral is a departure from positive
>> stability when you push things too far.
>
> Spiral instability.

Instability is not necessarily an oscillation. You said oscillation.
You are wrong

>
>> Absolutely and totally incorrect.
>
> It depends on the aircraft, but my generalization is mostly valid.

No it isn't. If you think the control surfaces can't move without
either the pilot or the autopilot acting on them, you're daft. It's
true in EVERY SINGLE AIRPLANE IN THE WORLD. Have you ever heard of
the concept of trim? This is a little aerodynamic device that moves
the control surface dynamically to obtain given stable position.

Further some airliners don't even have a direct connection between
the yoke/autopilot and the control surface. Instead, these are
connected to a servo tab that moves the surface by aerodynamic means.
>
>> You should go read a introductory
>> pilots book section on flight aerodynamics.
>
> That's the problem with pilots' books: they never go past the introduction to
> these complex topics.

Yes, but they explain the simple topics you don't seem to begin to
understand.

[EridanMan]

> I have never claimed to know everything. I don't need to fly to know things.

You tone and stubborn refusal to offer any form of disclaimer on your
statements makes it appear to a great majority of the people on this
board that you do claim to authoritatively "Know" what is merely your
limited understanding.

> Coordinated turns maintain an acceleration vector parallel to the yaw axis.
> It is impossible to do this in a 90-degree bank. There is always a vertical
> component produced by gravity, and this means the acceleration vector can
> never be completely horizontal, and yet it would have to be in a 90-degree
> bank for a coordinated turn. The horizontal component would have to be of
> infinite magnitude, which is not possible.

A barrel roll is a coordinated maneuver through 90 degrees of bank.
Once again you are incorrect.

[TheSmokingGnu]

Nomen Nescio wrote:
> In a 45 deg turn there are 2 acceleration vectors in play.

There's a critical flaw in your theory, see if you can spot it.

There are always, always, always 4 vectors in play when examining
aircraft flight. Lift, weight, thrust and drag.

> Nope. MX is right again.

Here's where the both of you are incorrect. You fail to account for the
thrust vector (discount the drag vector, since it's inception (and thus
its balance) results from the lift vector).

While in flight, two "positive" vectors (namely, lift and thrust) act
against their negatives (namely, weight and drag). In order to maintain
altitude, the sum of the positive vectors must equal the sum of the
negatives, in any combination thereof.

In a 90 deg turn, your lift vector is turned fully sideways, and so for
all practical purposes does nothing to counteract weight. But what of
your (independent) thrust vector? If your thrust vector is directed such
that it's total direction counteracts weight, you can maintain any bank
angle you like while maintaining altitude.

Thus, you can maintain altitude in a 90 deg bank by properly maneuvering
the aircraft into a steep climb first (to tilt the lift vector into a
horizontal and vertical component), and then rolling over into the bank.
Coordination is possible without even touching the rudder pedals
(assuming that the pedals are trimmed when in level flight), since you
aren't turning so much as trying to climb sideways.

Fallacy, from hell's heart, I stab at thee!

TheSmokingGnu

[TheSmokingGnu]

TheSmokingGnu wrote:
> Fallacy, from hell's heart, I stab at thee!

Here, I've created visual aids to more properly illustrate the point:

Page 1:

http://img241.imageshack.us/my.php?image=page1xd7.jpg

Page 2:

http://img157.imageshack.us/my.php?image=page2tj4.jpg

TheSmokingGnu

[Mxsmanic]

Ron Natalie writes:

> Not true. In a normal coordinated turn (lets do 45 degrees of bank),
> the acceleration vector points towards the inside of the turn. The
> yaw axis itself is canted at a 45 degree angle.

And so is the acceleration vector, which will match the bank angle in a
coordinated turn. It is thus parallel to the yaw axis, which is also
congruent with the bank angle.

> Sorry, that's untrue. The acceleration is always horizontal in a level
> turn regardless of bank.

The acceleration due to gravity is always present and cannot be overcome. As
a result, the pilot is always being accelerated upward in an aircraft, in a
coordinated turn or in level flight. The only way to negate this from the
pilot's frame of reference is to accelerate the aircraft downward at one
gravity.

> That would be news to a lot of acro pilots.

Maybe, depending on how much theory they've learned. Careful measurement
would prove it, though.

--
Transpose mxsmanic and gmail to reach me by e-mail.

[Mxsmanic]

Nomen Nescio writes:

> If you're holding a 90 deg bank with no loss of altitude, then you're
> not coordinated.

Yes. In fact, you cannot hold a 90-degree bank in a coordinated turn unless
you are accelerating downward at 1 G. If you start at 10,000 feet and respect
this condition, you'll hit the ground in 25 seconds, with a descent rate of
48,000 feet per second. In practice, though, your small aircraft will break
up within 15 seconds or so, so you'll never get that far.

There are many factors at work here and calculating it all out is complicated.
For all practical purposes, you cannot maintain a coordinated turn in a
90-degree bank, period, and you absolutely cannot do it while maintaining your
altitude, ever.

--
Transpose mxsmanic and gmail to reach me by e-mail.

[Mxsmanic]

TheSmokingGnu writes:

> There's a critical flaw in your theory, see if you can spot it.
>
> There are always, always, always 4 vectors in play when examining
> aircraft flight. Lift, weight, thrust and drag.

Those are not accelerations.

In all phases of flight, you are subject to the acceleration due to gravity.
In turns, you are also subject to acceleration towards the center of your
turn. The net acceleration to which you are subject in turns is a composite
of these individual accelerations. In a turn at constant altitude, you cannot
negate the acceleration due to gravity, and so you cannot ever achieve a
90-degree bank, which would require a zero vertical component to your
acceleration. And you cannot accelerate downward fast enough and long enough
to negate that vertical component in any turn.

This discussion illustrates the extent to which many pilots don't understand
(or don't know) the theory behind their flying. It's a consequence of rote
learning. Rote learning is easier but it prevents any thinking outside the
box that it creates.

> Here's where the both of you are incorrect. You fail to account for the
> thrust vector (discount the drag vector, since it's inception (and thus
> its balance) results from the lift vector).

There aren't any such vectors. There are a horizontal acceleration and a
vertical acceleration. Thrust, lift, and drag are irrelevant.

The vertical acceleration is induced by gravity; it cannot be eliminated. The
horizontal acceleration is a consequence of the curving trajectory of the
aircraft in a turn. The net acceleration vector must be horizontal to produce
a 90-degree bank in a coordinated turn, but it can never be horizontal,
because its vertical component can never be eliminated. Thus 90-degree banks
in coordinated turns are impossible.

Thrust, lift, and drag have nothing to do with any of this.

> While in flight, two "positive" vectors (namely, lift and thrust) act
> against their negatives (namely, weight and drag). In order to maintain
> altitude, the sum of the positive vectors must equal the sum of the
> negatives, in any combination thereof.

You're reciting what you've learned by rote, and it's not applicable here.

> In a 90 deg turn, your lift vector is turned fully sideways, and so for
> all practical purposes does nothing to counteract weight. But what of
> your (independent) thrust vector? If your thrust vector is directed such
> that it's total direction counteracts weight, you can maintain any bank
> angle you like while maintaining altitude.

You can, but it won't be a coordinated turn. In a coordinated turn with a
90-degree bank, the net acceleration of the pilot must be entirely horizontal,
and that is impossible, because of gravity, which constantly accelerates the
pilot vertically.

> Thus, you can maintain altitude in a 90 deg bank by properly maneuvering
> the aircraft into a steep climb first (to tilt the lift vector into a
> horizontal and vertical component), and then rolling over into the bank.
> Coordination is possible without even touching the rudder pedals
> (assuming that the pedals are trimmed when in level flight), since you
> aren't turning so much as trying to climb sideways.

No, you're incorrect.

Switch from rote learning to theory. It takes longer but it works in all
contexts, not just the ones in which it is first illustrated.

--
Transpose mxsmanic and gmail to reach me by e-mail.

[Mxsmanic]

EridanMan writes:

> You tone and stubborn refusal to offer any form of disclaimer on your
> statements makes it appear to a great majority of the people on this
> board that you do claim to authoritatively "Know" what is merely your
> limited understanding.

Their errors in interpretation are not under my control and are not my
responsibility.

> A barrel roll is a coordinated maneuver through 90 degrees of bank.

Instantaneously passing through 90 degrees is not the same as a coordinated
turn with a bank angle of 90 degrees. The first is possible; the second is
not.

> Once again you are incorrect.

I purposely mentioned this because so many pilots don't understand it and get
it wrong. You're in good company, though, as even some very good pilots get
completely lost on this. And that's simply because pilot training is normally
rote learning, rather than theory. Rote learning is fine, as long as you
limit yourself to situations in which the rote learning applies. In other
situations, though, you need theory (or different rote learning), or you get
into trouble.

--
Transpose mxsmanic and gmail to reach me by e-mail.

[TheSmokingGnu]

Mxsmanic wrote:
> Those are not accelerations.

They don't have to be accelerations, VECTORS AREN'T ACCELERATIONS.
They're VELOCITIES.

That's why your plan fails on it's face, because you think they're
accelerations (which are _NOT_ measures of speed, but measures of CHANGE
in speed).

Take a first year calculus course.

>
> In all phases of flight, you are subject to the acceleration due to gravity.

Which we in the real world term "weight". Next.

> In turns, you are also subject to acceleration towards the center of your
> turn.

Again, we call this the "horizontal component of lift". It is really a
velocity vector with arbitrary resultant acceleration. Next.

> The net acceleration to which you are subject in turns is a composite
> of these individual accelerations.

The acceleration to which you are subject in turns is the sum of the
derivatives of vectors in the turn (namely, the acceleration). However,
that's an arbitrary figure, since it DOESN'T MATTER to the hypothetical.
The SUM OF THE VELOCITY VECTORS is the SUM VELOCITY to which you are
subject, and the force which the pilot must balance in a turn.

> This discussion illustrates the extent to which many pilots don't understand
> (or don't know) the theory behind their flying. It's a consequence of rote
> learning. Rote learning is easier but it prevents any thinking outside the
> box that it creates.

I'll take your veiled attack and raise you another. Answer my other
post, you ninny.

> There aren't any such vectors. There are a horizontal acceleration and a
> vertical acceleration. Thrust, lift, and drag are irrelevant.

What in the hell do you think acceleration comes from? From velocity.
Acceleration is the rate of change of velocity, so in order for your
accelerations to exist, there must be some velocity. The velocities of
the forces (represented by vectors) acting on an aircraft are what is
important here, not the arbitrary acceleration.

> The vertical acceleration is induced by gravity; it cannot be eliminated.

Then I submit that level (and climbing) flight should be impossible.

Here's where that grounding in basic vector math would have helped.

Gravity always pulls on us at some acceleration (32 ft/sec^2), and so
always engenders some velocity because of it (without additional
forces). An aircraft wing produces lift opposing gravity, and if it's
level flight, then must also be producing enough lift such that the net
acceleration vector of the aircraft is zero (The vertical velocity
vector of lift being equal to the velocity engendered by gravity's
acceleration). But wait, you say, doesn't that mean level aircraft
eliminate the vertical acceleration induced by gravity?. An aircraft in
climb must induce enough lift such that it's positive velocity vector is
GREATER than the velocity engendered by gravity's acceleration.

Next.

> You can, but it won't be a coordinated turn. In a coordinated turn with a
> 90-degree bank, the net acceleration of the pilot must be entirely horizontal,
> and that is impossible, because of gravity, which constantly accelerates the
> pilot vertically.
>

Here again, you fail to account for the velocity (or even the
acceleration) of the thrust vector. What keeps the plane moving forward
and generating lift? You're thinking of an aircraft as a stone trying to
move sideways across gravity, not as a dynamic mechanical instrument.

All my model requires is an aircraft with perfect neutral stability and
a well-placed CG, and that's it. You don't use rudder pressure to hold
the nose up, it stays there as a consequence of being hypothetically
balanced.

> No, you're incorrect.

Once again, acceleration is the rate of change of velocity, and so isn't
applicable to this situation; I could care less how the velocities are
changing. What I care about is the sum total of those velocity vectors,
since velocity is how and where the aircraft is moving. Make the
velocities equal, and you can maintain level flight.

Take an aircraft in level flight again. All velocities are equal (and so
unchanging), and so net acceleration (in ALL AXES) is zero.

Now, bank the aircraft. Your lift vector "splits" into a remaining
vertical component and a new horizontal component. Now, your vertical
lift component is less than your weight vector, and so to counter-act
this, you raise the nose slightly, splitting your thrust vector into a
vertical and horizontal component (and now, you increase thrust so that
your remaining horizontal. component of thrust is still equal to your
drag, and you maintain airspeed; discount for this discussion).

The SUM TOTAL of the vertical vectors (remaining lift and new thrust)
are EQUAL to the weight vector, and so the aircraft maintains it's altitude.

Take the example to the logical extreme, and move your lift vector
completely to the horizontal. You must now move the nose such that your
thrust vector can balance your weight solely on it's new vertical
component in order to maintain altitude. Obviously, this _IS_ impossible
for most aircraft, but we are speaking in hypothetical.

Level flight requires that the vertical accelerations necessarily BE
zero, such that you relationship to Earth does not change. You do this
by balancing forces, which we may represent en individuo as velocities.

Quod Erat Demonstrandum.

> Switch from rote learning to theory. It takes longer but it works in all
> contexts, not just the ones in which it is first illustrated.

Switch from contemplation to mathematical theory. It is painfully
obvious to anyone with even a small background in higher math that you
have absolutely no idea what you're putting down on the page, and you're
trying to obfuscate your lack of understanding with big words, which is
never a good way to bull****.

TheSmokingGnu

[Ron Natalie]

Mxsmanic wrote:
> Ron Natalie writes:
>
>> Not true. In a normal coordinated turn (lets do 45 degrees of bank),
>> the acceleration vector points towards the inside of the turn. The
>> yaw axis itself is canted at a 45 degree angle.
>
> And so is the acceleration vector, which will match the bank angle in a
> coordinated turn. It is thus parallel to the yaw axis, which is also
> congruent with the bank angle.

No it's not. You should first learn something about physics and the
definition of acceleration.
>
>> Sorry, that's untrue. The acceleration is always horizontal in a level
>> turn regardless of bank.
>
> The acceleration due to gravity is always present and cannot be overcome.

It is always present, but it's easy to overcome. Apply a force in the
opposite direction. Your analysis lacks two basic understandings.

1. To look at the resultant flight path (a turn) and whether there is
coordination or not, you must some all the forces (accelerations). In
a turn that does not have any resultant vertical acceleration (you are
not changing vertical speed) the total acceleration is towards the
inside of the turn. That is all that's required.

2. You seem to think that the only aerodynamic force acting on the
plane is a lift vector perpendicular to the wing. That's not true.

Aircraft can fly coordinated in knife edge flight for the same reasons
that they can fly inverted (which I assume you'll tell me is equally
impossible).

[Ron Natalie]

Mxsmanic wrote:
> TheSmokingGnu writes:
>
>> There's a critical flaw in your theory, see if you can spot it.
>>
>> There are always, always, always 4 vectors in play when examining
>> aircraft flight. Lift, weight, thrust and drag.
>
> Those are not accelerations.

Here's where your lack of understanding of simple physics come into
play. THEY ARE ACCELERATIONS. They are forces. Since F=ma and
the mass is the same for all of them, they result in corresponding
acellerations.

>
> In all phases of flight, you are subject to the acceleration due to gravity.

Which is called weight. There is also lift, thrust, and drag.

> In turns, you are also subject to acceleration towards the center of your
> turn. The net acceleration to which you are subject in turns is a composite
> of these individual accelerations.

Precisely. The vertical acceleration cancels out the weight (gravity)
acceleration. The resultant acceleration is horizontally to the inside
of the turn.

> In a turn at constant altitude, you cannot
> negate the acceleration due to gravity, and so you cannot ever achieve a
> 90-degree bank, which would require a zero vertical component to your
> acceleration.

You keep making the assumption that there is no upwards force on the
aircraft in a 90 degree bank. This assumes that the only force that
could possibly contribute to this is a force perpendicular to the wing.
This is just plainly not true. You can have lift generated from
other pieces of the aircraft. You can have a vertical component
from thrust.


>
> This discussion illustrates the extent to which many pilots don't understand
> (or don't know) the theory behind their flying. It's a consequence of rote
> learning. Rote learning is easier but it prevents any thinking outside the
> box that it creates.

No it indicates how much you don't know.
>

[Ron Natalie]

TheSmokingGnu wrote:
> Mxsmanic wrote:
>> Those are not accelerations.
>
> They don't have to be accelerations, VECTORS AREN'T ACCELERATIONS.
> They're VELOCITIES.
>
A vector is just a quantity with a magnitude and direction. Lift,
Thrust, Drag, and Weight are forces that can be represented by
vectors. Since Force is mass times acceleration, and since the
mass (the mass of the aircraft) is the same for all of these,
each of these terms also corresponds to an acceleration.

The sum of all the forces yields an net acceleration. This
acceleration affects the velocity over time. The velocity
over time affects the aircraft position.

In a level, constant airspeed turn (no vertical acceleration,
no longitudinal acceleration) the sum of these accelerations
is a vector pointing horizontally inward to the center of the
turn. This is what causes the resultant flight track to
curve.

[TheSmokingGnu]

Ron Natalie wrote:
> A vector is just a quantity with a magnitude and direction. Lift,
> Thrust, Drag, and Weight are forces that can be represented by
> vectors. Since Force is mass times acceleration, and since the
> mass (the mass of the aircraft) is the same for all of these,
> each of these terms also corresponds to an acceleration.

Right, when taken as individual components each carries an acceleration,
and what we're primarily concerned with is the resultant net
acceleration (which comes from the net velocity of the aircraft).

> The sum of all the forces yields an net acceleration. This
> acceleration affects the velocity over time. The velocity
> over time affects the aircraft position.

Right, I was just arguing for a single point in time, at which you'd
only have to consider the velocity vectors as applicable (makes the
argument much more simple).

>
> In a level, constant airspeed turn (no vertical acceleration,
> no longitudinal acceleration) the sum of these accelerations
> is a vector pointing horizontally inward to the center of the
> turn.

Also right (darn, you make this no fun! :D ). Since the horizontal
component of lift has no "balance" force, it's velocity vector naturally
accelerates the aircraft around the centroid of the turn (by "pulling"
it that-a-way).

TheSmokingGnu

[Ron Natalie]

TheSmokingGnu wrote:

>> In a level, constant airspeed turn (no vertical acceleration,
>> no longitudinal acceleration) the sum of these accelerations
>> is a vector pointing horizontally inward to the center of the
>> turn.
>
> Also right (darn, you make this no fun! :D ). Since the horizontal
> component of lift has no "balance" force, it's velocity vector naturally
> accelerates the aircraft around the centroid of the turn (by "pulling"
> it that-a-way).

Accelerations do not have "velocity" vectors. They will change an
existing velocity vector torwards themselves. That is the, inward
acceleration, moves the velocity vector which is pointing straight
ahead into a turn.

Of course, if this was the only aerodynamic force in play, then
the aircraft wouldn't in fact turn, but rather just translate
to the left. However, once the aircraft begins to slide to
the left, the vertical surfaces (the tail, rudder, and the
side of the fuselage) causes the aircraft to weathervane into
the wind (essentially what we mean by coordination, the ass-end
of the aircraft is now flying behind the front in the windstream).
Now with the horizontal acceleration vector is slightly turned
(still heading towards the center point of the turn.

[Ron Natalie]

Nomen Nescio wrote:
> -----BEGIN PGP SIGNED MESSAGE-----
>
> From: Mxsmanic >
>
>> Yes. In fact, you cannot hold a 90-degree bank in a coordinated turn unless
>> you are accelerating downward at 1 G. If you start at 10,000 feet and respect
>> this condition, you'll hit the ground in 25 seconds, with a descent rate of
>> 48,000 feet per second.
>
> You may want to check your math, again.
> Hint: 48k ft/sec is WAY off.
> And, of course, you're not flying in a vacuum.
>
>
Yes, at that velocity, about Mach 40, the aircraft would be in little
pieces long before it hit the ground.

[601XL Builder]

Ron, you might want to try this.

1. Find a brick wall.
2. Slam you head against it as hard as you can.

It will probably be less painful for you and certainly less painful for
us. Also, the brick wall will stand a better chance of learning from the
experience than Anthony.

[Mxsmanic]

TheSmokingGnu writes:

> Again, we call this the "horizontal component of lift". It is really a
> velocity vector with arbitrary resultant acceleration. Next.

You're repeating what you've learned by rote; you're even quoting it for
comfort. You have to learn the theory.

There are many errors in the rest of your post, so I shall not address it
further here.

--
Transpose mxsmanic and gmail to reach me by e-mail.

[Mxsmanic]

Nomen Nescio writes:

> You may want to check your math, again.

Sorry, I should have typed feet per minute, not feet per second. Your final
speed would be 800 feet per second, or 48,000 fpm.

> And, of course, you're not flying in a vacuum.

True. The aircraft would disintegrate from aerodynamic stresses long before
it reached that speed. I estimate about 10-15 seconds before it would break
up.

--
Transpose mxsmanic and gmail to reach me by e-mail.

[Mxsmanic]

Ron Natalie writes:

> Yes, at that velocity, about Mach 40, the aircraft would be in little
> pieces long before it hit the ground.

Even at 48,000 fpm, it would be in pieces long before it hit the ground.

The overall point is that it cannot be done.

--
Transpose mxsmanic and gmail to reach me by e-mail.

[Mxsmanic]

Ron Natalie writes:

> No it's not. You should first learn something about physics and the
> definition of acceleration.

Your posts also contain quite a few errors, and I shall not address them
individually. I've illustrated what I wanted to illustrated. I'll now let
you all bicker among yourselves, and I predict that those who didn't already
understand the theory will still not understand it after the bickering
subsides (and vice versa).

--
Transpose mxsmanic and gmail to reach me by e-mail.

[TheSmokingGnu]

Nomen Nescio wrote:
> Wrong. A "vector" is anything with both a magnitude and a direction.

Clarity is in order; I meant _my_ vectors (in the model). Sorry if that
was unclear.

>> In all phases of flight, you are subject to the acceleration due to gravity.
>
> Which we in the real world term "weight". Next.
>
> Nope. Weight is a "force".

Of course it's a force, resultant from the acceleration due to gravity.
Assume your mass doesn't change (and so is a constant), then F is
proportional to A, and we can conclude that without the acceleration due
to gravity, we have no weight.

Thus, we may postulate that the acceleration due to gravity is weight.

>> Again, we call this the "horizontal component of lift". It is really a
>> velocity vector with arbitrary resultant acceleration. Next.
>
> Nope. The "horizontal component of lift" is also a force and is
> equal to [mass(M)]x[acceleration(A)] .......also (M)x(dV/dT).

See the above. Also, acceleration prevails while time is arbitrary,
velocity prevails where time is fixed (as in my example).

> WTF does that mean?

It means I'm not concerned with acceleration since the model only
applies to a fixed moment in time, and only velocity known. In short, I
don't care how the plane got there, what it's trying to do, or where
it's going, I've simply broken down one single infinitessimal point of
time into it's factors.

> I don't like the term "eliminate". How about "balance"?

It is eliminating the acceleration, since the net is a difference of
gravity minus lift.

> A steady state climb is exactly the same as "straight and level" with
> one exception....the angle of the component vectors relative to the axis
> of the plane.

Incorrect, the angle of vectors relative to the aircraft have nothing to
do with climbing; I can climb in the same attitude I cruise at by
increasing thrust (and thereby increasing airspeed, increasing lift).
The lift and thrust vectors are still in the exact same angle (as is the
aircraft), but are now larger than their counterparts. The sum of the
vertical components of lift and thrust is greater than the vertical
components of weight (and thrusts horiz. component is met by drag)

> This is where the argument breaks down. Force cannot be represented
> as velocity. You MUST have a change in velocity (F=M (dA/dT))

Must? Hardly. Change in velocity only occurs where time prevails, we may
consider the vectors of velocity as the static results of forces acting
on the plane leading up to our example. Unequal acceleration causes
velocity, and within a fixed time reference, are the only numbers to be
concerned with; if the velocity vectors are equal across the forces,
then the plane is maintaining altitude. Simple as that.

TheSmokingGnu

[TheSmokingGnu]

Mxsmanic wrote:
> You're repeating what you've learned by rote; you're even quoting it for
> comfort.

It's not rote if it's the correct physical theory behind flight
dynamics, moron. You have to repeat the truth, it's hard to argue
fallacy (although you do seem to get along fine).

> There are many errors in the rest of your post, so I shall not address it
> further here.

Can't disprove what isn't wrong, eh?

You're avoiding the debate entirely. Such is the fate of the
intellectually defeated.

TheSmokingGnu

[EridanMan]

> Their errors in interpretation are not under my control and are not my
> responsibility.

By the simple, practical definition of communication, if the majority
of people reading your statements suffer 'errors in interpretation',
then it stands to simple reason that the fault lies with the initial
expression.

> Instantaneously passing through 90 degrees is not the same as a coordinated
> turn with a bank angle of 90 degrees. The first is possible; the second is
> not.

That was my point, you stated that it was impossible to _ATTAIN_ a
coordinated to 90 degrees of bank even for an instant, let alone
sustained. I was simply pointing out a case that shows you are
incorrect, as a barrel roll is does indeed allow a coordinated
aircraft to swing well past 90 degrees of bank by using vertical
momentum to offset the gravity vector.

I would not and did not argue that it is possible to _SUSTAIN_ a 90
degree bank in a coordinated turn... I simply called you on yet
another one of your over-generalizations.

> I purposely mentioned this because so many pilots don't understand it and get
> it wrong. You're in good company, though, as even some very good pilots get
> completely lost on this.

Please cite where I made the assertion which puts me "in good
company"...

> And that's simply because pilot training is normally
> rote learning, rather than theory.

You simply DO NOT KNOW THIS. (Pilot training varies wildly by
instructor and trainee, so this is also a ridiculously poor
generalization)

> Rote learning is fine, as long as you
> limit yourself to situations in which the rote learning applies. In other
> situations, though, you need theory (or different rote learning), or you get
> into trouble.

And all of the theory in the world is just numbers on a page until you
experience the real life situations in which the theoretical models
are valid. You know the models. I know the models _and_ what they
mean in the air.

And I'll say again, I have respect for the amount you've learned about
aviation DESPITE not being a pilot... however, you still suffer the
sophomoric tendency to over-generalize the theoretical models that you
do know to cover for that which you don't... Which in and of itself
wouldn't be a bad thing if, to resort to slang, "You weren't such a
dick about it".

And, again I need to come back to a simple practical question - if you
have so little respect for the knowledge of the people on this forum,
WHY DO YOU CONTINUE TO RETURN TO IT? You've stated repeatedly that we
do not provide you adequate answers to your queries... You cannot
carry on a discussion here that does not manifest puerile behavior...

Is your time really so value-less that you continue to consider this a
worthwhile use of it?

[Dave[_3_]]

Sorry... in knife edge flight, the "ball" is hard at the end of it's
travel....not "co-ordinated" as in the descriptive "co-ordinated
turn."

.......and your butt is definately NOT planted in the seat...

Can you "cordinately" use the controls to maintain knife edge
flight? Yes, with sufficient rudder , side area and power....

Dave



>
>Aircraft can fly coordinated in knife edge flight for the same reasons
>that they can fly inverted (which I assume you'll tell me is equally
>impossible).

[TheSmokingGnu]

Nomen Nescio wrote:
> You can be coordinated in any attitude for an infinitesimal interval
> of time. That's meaningless.

That's not the point I'm trying to make. Rather that at ANY point in
time (that point being any arbitrary but defined moment), the balance of
velocities must occur in order that altitude be maintained, not that I'm
measuring at just one point or holding the altitude for just one moment.
Think of the turn being composed of an infinite number of frames, each
one differentiable only by the difference in velocities; when you "play"
the turn through, you add the component of time (and acceleration), but
within each frame, you can only measure the velocity of each vector at
that precise moment.

> Try drawing that diagram and you'll see that the turn rate, and g force,
> must go to infinity to make that turn.

I did (it's about a dozen posts back).

The turn rate and G-forces do not go to infinity, because lift would
also have to be infinite. Place our hypothetical aircraft in a 90 degree
bank; thrust is now "split" between vertical and horizontal, the
horizontal being much, much less than it was in straight-and-level. Lift
is a function of the speed with which the wing is drawn through the
airstream, and so the lift vector is also reduced from it's level flight
magnitude. Coordination only dictates that the tail follow the fuselage,
and it can because the elevator now assumes the "yaw" function (from a
neutral outside observer), such that turn rate is infinitely
controllable without even touching the rudder pedals. The plane is as
eminently capable of static knife-edge flight as it is a coordinated
turn. For the purpose of keeping the tail following the fuselage, turn
rate is dictated by the control authority of the elevator, the rudder in
our hypothetical aircraft being unnecessary to keep the nose attitude
proper (that being handled by neutral stability and a conveniently
loaded CG).

> Only for a couple of seconds.

For all practical purposes, yes. This is a hypothetical aircraft with
lots of idealized characteristics. But it's not impossible from the
standpoint of the physics involved.

> In a steady state climb, the "lift" is exactly the same as it was during level
> flight. If it was greater, the rate of climb would continue to increase.
> All you've done by increasing the thrust in your case, or increasing
> the angle of attack in my case, is to temporarily increase the acceleration
> vector (vertical) for a very short (a few seconds) time.

And here's where what I've been arguing comes home to roost. Once the
steady state climb is established, the acceleration returns to zero, but
the VELOCITY is unequal. This is why you have to consider velocity in
the model, because it's the only unequal entity in the equation.

As long as the velocities are equal (which result from the acceleration
forces leading up to our frame of reference), then level flight is
maintained.

> I'm afraid that I don't have a clue as to what you're trying to say, here.

I believe my explanation was a bit more clear in this post, hopefully it
helps.

TheSmokingGnu

[Bertie the Bunyip[_2_]]

Mxsmanic > wrote in
:

> EridanMan writes:
>
>> You tone and stubborn refusal to offer any form of disclaimer on your
>> statements makes it appear to a great majority of the people on this
>> board that you do claim to authoritatively "Know" what is merely your
>> limited understanding.
>
> Their errors in interpretation are not under my control and are not my
> responsibility.
>
>> A barrel roll is a coordinated maneuver through 90 degrees of bank.
>
> Instantaneously passing through 90 degrees is not the same as a
> coordinated turn with a bank angle of 90 degrees. The first is
> possible; the second is not.
>

But that's not what you said, wannabe boi..


bertie

[Bertie the Bunyip[_2_]]

Mxsmanic > wrote in
:

> C J Campbell writes:
>
>> The fact that he is right once in awhile is no indication that he
>> knows what he is talking about.
>
> He is right more than just once in a while, and it is self-evident
> that if he is right, he knows what he is talking about, since the
> chance of a random answer being correct is exceedingly small.

As you prove daily.



Bertie

[Bertie the Bunyip[_2_]]

Mxsmanic > wrote in
:

> Nomen Nescio writes:
>
>> If you're holding a 90 deg bank with no loss of altitude, then you're
>> not coordinated.
>
> Yes. In fact, you cannot hold a 90-degree bank in a coordinated turn
> unless you are accelerating downward at 1 G. If you start at 10,000
> feet and respect this condition, you'll hit the ground in 25 seconds,
> with a descent rate of 48,000 feet per second. In practice, though,
> your small aircraft will break up within 15 seconds or so, so you'll
> never get that far.
>

Bwawhahwhahhwhahw!

where does one startt?



bertie

[Bertie the Bunyip[_2_]]

Mxsmanic > wrote in
:

> TheSmokingGnu writes:
>
>> There's a critical flaw in your theory, see if you can spot it.
>>
>> There are always, always, always 4 vectors in play when examining
>> aircraft flight. Lift, weight, thrust and drag.
>
> Those are not accelerations.
>
> In all phases of flight, you are subject to the acceleration due to
> gravity. In turns, you are also subject to acceleration towards the
> center of your turn. The net acceleration to which you are subject in
> turns is a composite of these individual accelerations. In a turn at
> constant altitude, you cannot negate the acceleration due to gravity,
> and so you cannot ever achieve a 90-degree bank, which would require a
> zero vertical component to your acceleration. And you cannot
> accelerate downward fast enough and long enough to negate that
> vertical component in any turn.
>
> This discussion illustrates the extent to which many pilots don't
> understand (or don't know) the theory behind their flying. It's a
> consequence of rote learning. Rote learning is easier but it prevents
> any thinking outside the box that it creates.
>
>> Here's where the both of you are incorrect. You fail to account for
>> the thrust vector (discount the drag vector, since it's inception
>> (and thus its balance) results from the lift vector).
>
> There aren't any such vectors.

Yes there is fjukktasrd


And I can assure you, I haven't learned this by rote..



Bertie

[Jim Logajan]

Mxsmanic > wrote:
> In all phases of flight, you are subject to the acceleration due to
> gravity.

That's conceptually incorrect. In this situation you would say the airplane
is subject to the _force_ of gravity, not the _acceleration_ of gravity. Or
you could say you are in a potential field of non-zero gradient. (The
latter has even more advantages for many computations and potential energy
is probably an even more fundamental concept than force.)

> The net acceleration to which you are subject in
> turns is a composite of these individual accelerations.

It is conceptually incorrect to add acceleration vectors. For example, what
acceleration are you adding to your computer monitor to counteract your
claimed gravitational acceleration? Are you claiming your table must
accelerate upward at 9.8 m/S^2 to keep your monitor from accelerating
downward at 9.8 m/S^2?

> This discussion illustrates the extent to which many pilots don't
> understand (or don't know) the theory behind their flying. It's a
> consequence of rote learning. Rote learning is easier but it prevents
> any thinking outside the box that it creates.

I've elided most of the rest of your post because it repeats the same
conceptual error. I am surprised you passed any of your physics exams.

It seems to me your understanding of physics was learned by rote (and
incorrectly) and you are being hypocritical in your assertions. If you
think you know physics well enough to defend your assertions then I can
propose some simple problems in statics and dynamics for you to solve to
demonstrate you actually understand the subject and have not simply learned
it by rote.

Jim Logajan, BSc in Physics, University of Minnesota

[Mxsmanic]

Jim Logajan writes:

> That's conceptually incorrect. In this situation you would say the airplane
> is subject to the _force_ of gravity, not the _acceleration_ of gravity. Or
> you could say you are in a potential field of non-zero gradient. (The
> latter has even more advantages for many computations and potential energy
> is probably an even more fundamental concept than force.)

Agreed, although in the fogginess of this discussion that distinction is
perhaps a trifle academic now.

> It is conceptually incorrect to add acceleration vectors.

That's why I said composite, and not sum.

--
Transpose mxsmanic and gmail to reach me by e-mail.

[Bertie the Bunyip[_2_]]

megaMAX > wrote in
:

> On Wed, 14 Mar 2007 01:18:33 +0100, Mxsmanic >
> wrote:
>
>>Most commercial flights are flown on autopilot for the vast majority
>>of the trip. Thus you would have seen autopilot corrections, not
>>pilot corrections.
>
> Yes, this is really probable, since it was a very regular and periodic
> correction, every few seconds.
>
>>Most likely there was nothing wrong, so there was nothing that needed
>>to be done. Constant small corrections are normal in flight. If
>>there are substantial winds aloft (and there usually are), the
>>corrections are likely to be mostly in one direction.
>
> Ok, but what about landing? The landing runway wasn't in the same
> direction of the rest of the flight, so the wind probably was blowing
> in a different direction.
>
> My sensation was that, at the moment of landing, the pilot was really
> not able to have a good trim due to a decise clockwise roll, that he
> was really not able to correct with the normal actions, despite of
> various tentatives. The impression was like that the right engine was
> not enough "powerful", or the airplane was heavier on the right side.
> Of course, impressions of a not-expert people.
>
> But since I had a large number of flights in my life and I know what
> happens in case of lateral wind, also during landing, I repeat that my
> sensation was not of lateral wind.
>
>>From your description, there is no reason to believe that the flight
>>was in any danger, and the corrections sound like nothing more than
>>what is normal for any flight.
>
> Ok, thank you: I was really calm during the flight, only after landing
> I was wondering about what has happened and I was curious about that.
>

you're an idiot


Bertie

[Bertie the Bunyip[_2_]]

Mxsmanic > wrote in
:

> C J Campbell writes:
>
>> Just so you know, Msxmanic does not know any more about flight than
>> you do. He is not a pilot.
>
> Correction: Actually, Mxsmanic knows a great deal,

No, you don't




bertie

[Bertie the Bunyip[_2_]]

Mxsmanic > wrote in
:

> EridanMan writes:
>
>> The problem is that you do not know what you do not know ...
>
> A greater problem is that a lot of pilots here don't know, either,

I do, and I know you are full of ****...



Bertie

[Bertie the Bunyip[_2_]]

Mxsmanic > wrote in
:

> TheSmokingGnu writes:
>
>> Do deny that airliners are fitted with artificial feel systems?
>
> Some are. But feel varies significantly from one aircraft to another.
> Sometimes it is simulated just because pilots expect it.

God you're clueless.



Bertei

[Bertie the Bunyip[_2_]]

Mxsmanic > wrote in
:

> TheSmokingGnu writes:
>
>> So you admit that in expecting it, the pilots must necessarily feel
>> it (or rather, expect to feel it; want to feel it; know that they
>> should feel it; know that it should exist).
>
> They want to feel it. They don't need it.


Yes, they do...



Bertie

[Bertie the Bunyip[_2_]]

Mxsmanic > wrote in
:

> MXMORON writes:
>
>> Since you haven't tried, how can you know this?
>
> Research.

Bwawhahhwhahwhahwhahwhahwhhahwhahwhahwhahhwhahwhah whahhwhahw!


You don't even know what they're for, fjukkkwit



bertie

[Bertie the Bunyip[_2_]]

Mxsmanic > wrote in
:

> george writes:
>
>> More than possible that the poster had a middle ear infection.
>
> I don't see the connection between a middle-ear infection and what he
> saw or believed.
>

of course you don't, but it's the first thing I thought of..

wonder why?


bertie

[Bertie the Bunyip[_2_]]

Mxsmanic > wrote in
:

> writes:
>
>> Yes, they can.
>
> No, they cannot, except under ideal conditions, and sometimes not even
> then.
>
>> But what do I know, I only fly tiny planes.
>
> My thoughts exactly.

Bwawhahhwhahwhahhwhahwhahhwha!

Fjukkwit


bertie

[Bertie the Bunyip[_2_]]

Mxsmanic > wrote in
:

> EridanMan writes:
>
>> They do not have too. They only need to get the aircraft close
enough
>> for wing dihedral to do the rest. Its called a dynamically stable
>> aircraft design, and its been a cornerstone of aviation almost since
>> its inception.
>
> Until Airbus came along.

Again, you know not of whence you speak....


Bertie

[Bertie the Bunyip[_2_]]

Mxsmanic > wrote in
:

> EridanMan writes:
>
>> Minor Harmonic oscillations in flights are a natural byproduct of the
>> dynamic stability of modern aircraft. The Autopilot has no part in
>> it.
>
> Do these oscillations cause control surfaces to move by themselves?
> Are they asymmetrical?
>
>> When the oscillations are on the Longitudinal axis, they are called
>> phugoid oscillations, I'm not sure if there is a similar term for the
>> roll equivolents ...
>
> Dutch roll and spiral come to mind, although they are not limited
> exclusively to the roll axis.
>

You don't even know what either of those are fjukkwit


Bertie

[Bertie the Bunyip[_2_]]

Mxsmanic > wrote in
:

> Ron Natalie writes:
>
>> And you profess to know everything even though you fly nothing.
>
> I have never claimed to know everything. I don't need to fly to know
> things.
>

Of course not. But you don't know **** anyway.

remarkable achievment!


Bertie

[Roger[_4_]]

On Tue, 13 Mar 2007 22:50:34 -0700, C J Campbell
> wrote:

>On 2007-03-13 16:08:34 -0700, megaMAX
> said:
>
>> Hello everybody,
>> I want to tell you what's happened during a Finnair flight from
>> Helsinki to Milan, I'm not an expert of flight.
>>
>> During the entire flight, I noticed that the aircraft was continuosly
>> rolling to right, and the pilot was correcting every 10-20 seconds the
>> attitude. I noticed this, because I was looking to the right wing and
>> the wing was continuosly going down of few centimeters, and after few
>> seconds there was a slight correction.
>
>Not unusual at all. It could just be normal cycling of the autopilot.

Or even normal flexing in turbulence. In the larger planes it's not
unusual to see a foot or so of movement.

I've been on a 737 where it was a pretty rough ride. You could watch
those wing tips going up and down and even the engine nacels shaking.
Of course there were only about 10 of us who weren't talking to RALPH
in a lunch bag.

Of course we didn't hit the rough air until they were picking up
*after* breakfast. I think a lot of Wheaties and milk curdled.
Riding in a plane with over a 100 puking passengers in definitely not
my idea of fun!
Roger Halstead (K8RI & ARRL life member)
(N833R, S# CD-2 Worlds oldest Debonair)
www.rogerhalstead.com

[Mortimer Schnerd, RN[_2_]]

Roger wrote:
> Of course we didn't hit the rough air until they were picking up
> *after* breakfast. I think a lot of Wheaties and milk curdled.
> Riding in a plane with over a 100 puking passengers in definitely not
> my idea of fun!



Pansy. I laugh at puke.... as long as you don't get any on me. It goes back to
my days running a dive shop. We'd go out on the water and somebody would
invariably get seasick: "Hey, you gonna eat that sandwich?"




--
Mortimer Schnerd, RN
mschnerdatcarolina.rr.com