Standby Vacuum?

Maule Driver wrote:
: As a recreational pilot of a simple IFR aircraft, I've recently
: discovered a great role for the T&B; staying on heading. After a few
: years of struggling to keep my non-AP equipped flivver on a MH, I've
: re-discovered what many must know. The T&B is the best instrument to go
: straight with. The AI gives you good info, and the heading gyro does
: too, but the best way to keep it all centered in my Maule is definitely
: the T&B. Especially in calm conditions.

I don't know if I'll agree with that. Once you dial in your wind correction
angle, the DG is the primary instrument for bank in straight-level flying.

When I was working on the instrument written, I tried to find easy ways to
remember primary vs supporting instruments for different stages of flight. One of my
conclusions was that for long-term accuracy, the instruments that provide the integral
of the chosen parameter are the most accurate, and thus "primary." For instance,
the result of a pitch change integrated gives you altitude, so it's primary for
straight-level. The result of a bank change integrated yields a heading, so the DG is
primary.

The trouble with direct-read indications is that they are not accurate enough
for long-term useage. The AI is good for radical attitude changes, but you cannot see
a 1/10 stdrad turn on either it or the T&B/TC. You *will* see it on the DG as the
numbers slows roll by.

Of course, to each their own. Just so long as you keep the shiny-side up!...


-Cory

************************************************** ***********************
* Cory Papenfuss *
* Electrical Engineering candidate Ph.D. graduate student *
* Virginia Polytechnic Institute and State University *
************************************************** ***********************

On 8/18/2005 10:49, wrote:

Maule Driver wrote:
: As a recreational pilot of a simple IFR aircraft, I've recently
: discovered a great role for the T&B; staying on heading. After a few
: years of struggling to keep my non-AP equipped flivver on a MH, I've
: re-discovered what many must know. The T&B is the best instrument to go
: straight with. The AI gives you good info, and the heading gyro does
: too, but the best way to keep it all centered in my Maule is definitely
: the T&B. Especially in calm conditions.

I don't know if I'll agree with that. Once you dial in your wind correction
angle, the DG is the primary instrument for bank in straight-level flying.

Here's another way to think about this.

I've done what Maule Driver is talking about, and think of it rather
like using the VSI to assist in maintaining altitude. I use the VSI
to give me an indication that an altitude change is coming, and I need
to anticipate it and correct (the VSI doesn't react all that quickly,
but still...)

If I do this right, I never see the altitude change. Of course,
this doesn't change the fact that the altimeter is the primary pitch
instrument - it's just not the only pitch instrument.

So ... I do the same with the T&B giving me an indication that a turn
is coming, and I can anticipate it and react. The DG is still the final
authority as to whether or not you're heading in the right direction, but
I think it's better to keep it on the heading, rather than notice it's
not and having to correct (when the turbulence allows, of course ;-) )



When I was working on the instrument written, I tried to find easy ways to
remember primary vs supporting instruments for different stages of flight. One of my
conclusions was that for long-term accuracy, the instruments that provide the integral
of the chosen parameter are the most accurate, and thus "primary." For instance,
the result of a pitch change integrated gives you altitude, so it's primary for
straight-level. The result of a bank change integrated yields a heading, so the DG is
primary.

The trouble with direct-read indications is that they are not accurate enough
for long-term useage. The AI is good for radical attitude changes, but you cannot see
a 1/10 stdrad turn on either it or the T&B/TC. You *will* see it on the DG as the
numbers slows roll by.

Of course, to each their own. Just so long as you keep the shiny-side up!...


-Cory

************************************************** ***********************
* Cory Papenfuss *
* Electrical Engineering candidate Ph.D. graduate student *
* Virginia Polytechnic Institute and State University *
************************************************** ***********************



--
Mark Hansen, PP-ASEL, Instrument Student
Sacramento, CA

Mark Hansen wrote:
: I've done what Maule Driver is talking about, and think of it rather
: like using the VSI to assist in maintaining altitude. I use the VSI
: to give me an indication that an altitude change is coming, and I need
: to anticipate it and correct (the VSI doesn't react all that quickly,
: but still...)

: If I do this right, I never see the altitude change. Of course,
: this doesn't change the fact that the altimeter is the primary pitch
: instrument - it's just not the only pitch instrument.

: So ... I do the same with the T&B giving me an indication that a turn
: is coming, and I can anticipate it and react. The DG is still the final
: authority as to whether or not you're heading in the right direction, but
: I think it's better to keep it on the heading, rather than notice it's
: not and having to correct (when the turbulence allows, of course ;-) )


Sure... they're all related of course. I guess the point I was trying to make
is that (barring turbulence), I don't *see* a change in VSI/AI/T&B in straight/level
cruise. A certain amount of pressure on the controls will fix small errors in DG/ALT.
Those are typical in non-turbulent flight, and there will be no perceptible indication
from the VSI/AI/T&B. For anything other than a minute change (e.g. turbulence) the
other indicators are better and then line up on the "primaries" (DG/ALT).

Like I said... to each their own. Probably saying the same thing anyway...

-Cory
--

************************************************** ***********************
* Cory Papenfuss *
* Electrical Engineering candidate Ph.D. graduate student *
* Virginia Polytechnic Institute and State University *
************************************************** ***********************

I never did get that whole primary secondary stuff to stick in my brain.
Let alone integration...

Obviously, we all have to scan to keep it all on track. No one has ever
figured out a universally applicable optimal procedure for scanning.
And I guess only eyeball scanning will ever tell us what one actually does.

Anyway, after reading several anecdotal references to increased use of
the T&B, I tried it. It worked. Specifically when hand flying the
trimmed out Maule.

Next time you droning along, trimmed out, with Ralph or Bob or whatever
his name is turned off, replace your use of the AI with the TC. Of
course the DG tells you how you are doing and which way to correct, but
try flying with the TC only for longer than you would normally. The
experience changed my scan.

I think Collins wrote something recently where someone was hand flying
on instruments from the right seat. They couldn't see the AI well so
they used the TC instead. Collins had to comment that they were
smoother and straighter than usual and the reason given was use of the TC.

wrote:
...the AI gives you good info, and the heading gyro does
: too, but the best way to keep it all centered in my Maule is definitely
: the T&B. Especially in calm conditions.

I don't know if I'll agree with that. Once you dial in your wind correction
angle, the DG is the primary instrument for bank in straight-level flying.

When I was working on the instrument written, I tried to find easy ways to
remember primary vs supporting instruments for different stages of flight. One of my
conclusions was that for long-term accuracy, the instruments that provide the integral
of the chosen parameter are the most accurate, and thus "primary." For instance,
the result of a pitch change integrated gives you altitude, so it's primary for
straight-level. The result of a bank change integrated yields a heading, so the DG is
primary.

The trouble with direct-read indications is that they are not accurate enough
for long-term useage. The AI is good for radical attitude changes, but you cannot see
a 1/10 stdrad turn on either it or the T&B/TC. You *will* see it on the DG as the
numbers slows roll by.

Of course, to each their own. Just so long as you keep the shiny-side up!...


-Cory

************************************************** ***********************
* Cory Papenfuss *
* Electrical Engineering candidate Ph.D. graduate student *
* Virginia Polytechnic Institute and State University *
************************************************** ***********************

Next time you droning along, trimmed out, with Ralph or Bob or whatever his name is turned off, replace your use of the AI with the TC. Of course the DG tells you how you are doing and which way to correct, but try flying with the TC only for longer than you would normally. The experience changed my scan.

I don't know why, but I never did use the AI much. I rely on the TC,
altimiter, DG, and airspeed to give me my picture, and leave the AI sort
of in the background. As a result, when the AI is covered, I fly
equally well. One CFI commented that I fly better on partial panel then
on the full panel.

Jose
--
Quantum Mechanics is like this: God =does= play dice with the universe,
except there's no God, and there's no dice. And maybe there's no universe.
for Email, make the obvious change in the address.

Jose wrote:
Next time you droning along, trimmed out, with Ralph or Bob or
whatever his name is turned off, replace your use of the AI with the TC.
Of course the DG tells you how you are doing and which way to correct,
but try flying with the TC only for longer than you would normally. The
experience changed my scan.

I don't know why, but I never did use the AI much. I rely on the TC,
altimiter, DG, and airspeed to give me my picture, and leave the AI sort
of in the background. As a result, when the AI is covered, I fly
equally well. One CFI commented that I fly better on partial panel then
on the full panel.

I have much the same experience. My instrument instructor was a nut
for partial panel practice, so I got really good at it. I miss the DG
when it's covered up, but for the most part, I fly the TC for bank and
the ASI for pitch.

After all these years, I honestly can't tell you how many bars up it
takes to get Vy or what bank angle it takes for a standard rate turn.

Roy Smith wrote:
: I don't know why, but I never did use the AI much. I rely on the TC,
: altimiter, DG, and airspeed to give me my picture, and leave the AI sort
: of in the background. As a result, when the AI is covered, I fly
: equally well. One CFI commented that I fly better on partial panel then
: on the full panel.

: I have much the same experience. My instrument instructor was a nut
: for partial panel practice, so I got really good at it. I miss the DG
: when it's covered up, but for the most part, I fly the TC for bank and
: the ASI for pitch.

: After all these years, I honestly can't tell you how many bars up it
: takes to get Vy or what bank angle it takes for a standard rate turn.

Whew... I thought I was the only one! In straight/level, I rarely look at the
AI except once in awhile to cross-check. For straight/level it's useless, just as the
T&B/TC is for bank. It's really only good for setting up an attitude (whether it be
intentional transition or an "Oh crap... I busted my altitute/heading!")

-Cory

--

************************************************** ***********************
* Cory Papenfuss *
* Electrical Engineering candidate Ph.D. graduate student *
* Virginia Polytechnic Institute and State University *
************************************************** ***********************

Jose wrote:
I don't know why, but I never did use the AI much. I rely on the TC,
altimiter, DG, and airspeed to give me my picture, and leave the AI sort
of in the background.

When I mostly flew an Archer, I did the same. Somehow in the transition to the
Mooney, I've becomre more fixated on the AI. Not sure why. I think my scan now
looks like that classic diagram in the training manuals where you look at the
AI, then some other instrument, then back to the AI, then some other instrument,
etc.

I've wondered whether the change is a function of performance / stability of the
airplane. The Archer was so stable it was easy to follow along just using the
result-based instruments. In the Mooney, it became necesary to be more aware of
slight changes in attitude that would affect the performance instruments in a
few seconds.

It also could be a better-quality AI in the Mooney that's easier to read.

The Mooney is the highest-performing airplane I've flown, but I've noticed that
people that fly jets seem to talk / write more about the importance of the AI.

....but I think you are experienced in higher-performance airplanes, right, Jose?

Dave

When I mostly flew an Archer, I did the same. Somehow in the transition to the
Mooney, I've becomre more fixated on the AI. Not sure why.

Because the Mooney demands more precision in your attitude control.
The cleaner the airplane, the more true that is. Once you reach the
ultimate clean airplane (a transport jet), there is no way to fly
partial panel. No jet crew that lost all attitude indicators in IMC
has ever survived. That's why the airlines have given up on teaching
partial panel. On the other hand, an old, slow, draggy ragwing can be
flown with no gyros at all, using just airspeed (or sound) for pitch
and compass for roll. I know someone who has over an hour of IMC time
in a ragwing with no gyros at all, doing it exactly that way. I've
done it at night under the hood in the TriPacer.

The Archer was so stable it was easy to follow along just using the
result-based instruments. In the Mooney, it became necesary to be more aware of
slight changes in attitude that would affect the performance instruments in a
few seconds.

Exactly correct.

This is why I teach the control-performance model of the scan - my
students are generally either flying slippery airplanes or are planning
to move up to them. For someone who will fly his entire career in an
Archer or Skyhawk, the FAA primary-secondary model works fine, and then
the AI is just a way to crosscheck.

Michael

...but I think you are experienced in higher-performance airplanes, right, Jose?

I've flown in transport category jets, but in the back seat. Way back.

I do have a little experience in high performance singles, but not very
much. And you are probably right about the AI being more critical in
high performance aircraft. Things happen faster.

Jose
--
Quantum Mechanics is like this: God =does= play dice with the universe,
except there's no God, and there's no dice. And maybe there's no universe.
for Email, make the obvious change in the address.