Methods for altitude changes

[Mxsmanic]

Suppose you're in your small aircraft and you want to climb from 4000 to 6000,
or descend from 6000 to 4000. What method do you use? I can think of
several, but I don't know which is best/recommended.

For example, to climb from 4000 to 6000, I can just ease the yoke back and
climb. When I get to 6000, I can adjust power and retrim. Another way is to
just add some nose-up trim, then retrim and adjust power when I'm at 6000.
Still another way is to increase power, and wait until I drift up to 6000,
then adjust power and retrim. Various other combinations are possible, such
as adjusting power and/or pitch and/or trim simultaneously, and so on.

Which method do you normally use? Is there a recommended method?

I make a distinction here between initial climbs/descents and extended
climbs/descents and small altitude changes. I presume it's not necessary to
worry too much about constant adjustment of mixture or things like that in a
change of only 2000 feet or so--it can always be adjusted after the target
altitude is reached. Similarly, although power must ultimately be adjusted
for any new altitude, it doesn't seem that it's really necessary during the
altitude change; a slight change in airspeed isn't that big a deal. This
would seem to leave a lot of room for personal preferences, which is why I ask
which methods are the most popular, and why.

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

[Bertie the Bunyip[_2_]]

Mxsmanic > wrote in
:

> Suppose you're in your small aircraft and you want to climb from 4000
> to 6000, or descend from 6000 to 4000. What method do you use?

Good grief, and you're presuming to tell anyone here anythign?

Bweawhahwhahwhahwhahwhahhwhahwhahhw!


Berti e

[Maxwell]

"Mxsmanic" > wrote in message
...
> Suppose you're in your small aircraft and you want to climb from 4000 to
> 6000,
> or descend from 6000 to 4000. What method do you use? I can think of
> several, but I don't know which is best/recommended.
>
> For example, to climb from 4000 to 6000, I can just ease the yoke back and
> climb. When I get to 6000, I can adjust power and retrim. Another way is
> to
> just add some nose-up trim, then retrim and adjust power when I'm at 6000.
> Still another way is to increase power, and wait until I drift up to 6000,
> then adjust power and retrim. Various other combinations are possible,
> such
> as adjusting power and/or pitch and/or trim simultaneously, and so on.
>
> Which method do you normally use? Is there a recommended method?
>
> I make a distinction here between initial climbs/descents and extended
> climbs/descents and small altitude changes. I presume it's not necessary
> to
> worry too much about constant adjustment of mixture or things like that in
> a
> change of only 2000 feet or so--it can always be adjusted after the target
> altitude is reached. Similarly, although power must ultimately be
> adjusted
> for any new altitude, it doesn't seem that it's really necessary during
> the
> altitude change; a slight change in airspeed isn't that big a deal. This
> would seem to leave a lot of room for personal preferences, which is why I
> ask
> which methods are the most popular, and why.
>

Relax, not matter which procedure you use, your desk will always remain
level, and at the same altitude.

[[email protected]]

In rec.aviation.piloting Mxsmanic > wrote:
> Suppose you're in your small aircraft and you want to climb from 4000 to 6000,
> or descend from 6000 to 4000. What method do you use? I can think of
> several, but I don't know which is best/recommended.

> For example, to climb from 4000 to 6000, I can just ease the yoke back and
> climb. When I get to 6000, I can adjust power and retrim. Another way is to
> just add some nose-up trim, then retrim and adjust power when I'm at 6000.
> Still another way is to increase power, and wait until I drift up to 6000,
> then adjust power and retrim. Various other combinations are possible, such
> as adjusting power and/or pitch and/or trim simultaneously, and so on.

> Which method do you normally use? Is there a recommended method?

> I make a distinction here between initial climbs/descents and extended
> climbs/descents and small altitude changes. I presume it's not necessary to
> worry too much about constant adjustment of mixture or things like that in a
> change of only 2000 feet or so--it can always be adjusted after the target
> altitude is reached. Similarly, although power must ultimately be adjusted
> for any new altitude, it doesn't seem that it's really necessary during the
> altitude change; a slight change in airspeed isn't that big a deal. This
> would seem to leave a lot of room for personal preferences, which is why I ask
> which methods are the most popular, and why.

It doesn't matter in Flight Simulator.

Why bother telling you what to do in a real airplane as you will just
argue about it and discard the information since you will never be in
a real airplane.

--
Jim Pennino

Remove .spam.sux to reply.

[flypaper]

Mxsmanic wrote:
> Suppose you're in your small aircraft and you want to climb from 4000
> to 6000

hit Y, then Q couple times, then Y again when alt reached... hth

[Maxwell]

"flypaper" > wrote in message
...
> Mxsmanic wrote:
>> Suppose you're in your small aircraft and you want to climb from 4000
>> to 6000
>
> hit Y, then Q couple times, then Y again when alt reached... hth
>

But smoothly, easy on the controls. Let the sim do the work.

[TheSmokingGnu]

Mxsmanic wrote:
> Suppose you're *simulating your small aircraft and you want to *simulate a climb from 4000 to 6000,
> or descent from 6000 to 4000. What method do you *simulate? I can think of
> several, but I don't know which is best/recommended to *simulate.

Funny that.

>
> For example, to *simulate a climb from 4000 to 6000, I can just *simulate easing the yoke back and
> climbing. When I get to a *simulated 6000, I can *simulate adjusting power and trim. Another way is to
> just add some *simulated nose-up trim, then re-trim and *simulate adjusting power when I'm at a *simulated 6000.
> Still another way is to *simulate an increase in power, and wait until I drift up to a *simulated 6000,
> then *simulate adjusting power and trim. Various other combinations are possible, such
> as *simulating adjusting power and/or pitch and/or trim simultaneously, and so on.

Only one of these is correct, and none of the situations you explicitly
described are correct.

>
> Which method do you normally use when *simulating? Is there a recommended method?

Yes.

>
> I make a distinction here between initial *simulated climbs/descents and *simulated extended
> climbs/descents and small altitude changes. I presume it's not necessary to
> worry too much about *simulated constant adjustment of mixture or things like that in a *simulated
> change of only 2000 *simulated feet or so--it can always be *simulated after the *simulated target
> altitude is reached.

You presume incorrectly.

> Similarly, although *simulated power must ultimately be adjusted
> for any new altitude, it doesn't seem that it's really necessary during the
> altitude change; a slight change in airspeed isn't that big a deal.

It's a big deal. It needs adjustment.

I have corrected some of the errors in enunciation, prose and grammar
where necessary. (denoted by *)

TheSmokingGnu

[Mxsmanic]

TheSmokingGnu writes:

> Only one of these is correct, and none of the situations you explicitly
> described are correct.

Which one is correct, and why?

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

[Maxwell]

"Mxsmanic" > wrote in message
...
> TheSmokingGnu writes:
>
>> Only one of these is correct, and none of the situations you explicitly
>> described are correct.
>
> Which one is correct, and why?
>

All of the above, because it's free country and just a simulated event.

[d.g.s.]

On 4/7/2007 1:20 PM Maxwell jumped down, turned around, and wrote:

> "Mxsmanic" > wrote in message
> ...
>> TheSmokingGnu writes:
>>
>>> Only one of these is correct, and none of the situations you explicitly
>>> described are correct.
>> Which one is correct, and why?
>>
>
> All of the above, because it's free country and just a simulated event.

Correct, and not only that, remember: you're just a name on a screen.
Anthony sez so!
--
dgs

[george]

On Apr 8, 8:20 am, "Maxwell" > wrote:
> "Mxsmanic" > wrote in message
>
> ...
>
> > TheSmokingGnu writes:
>
> >> Only one of these is correct, and none of the situations you explicitly
> >> described are correct.
>
> > Which one is correct, and why?
>
> All of the above, because it's free country and just a simulated event.


He -could- always fiddle with QFE to get from 4000 to 6000 :-)

[[email protected]]

On Apr 7, 9:11 am, Mxsmanic > wrote:
> Suppose you're in your small aircraft and you want to climb from 4000 to 6000,
> or descend from 6000 to 4000. What method do you use? I can think of
> several, but I don't know which is best/recommended.
>
> For example, to climb from 4000 to 6000, I can just ease the yoke back and
> climb. When I get to 6000, I can adjust power and retrim. Another way is to
> just add some nose-up trim, then retrim and adjust power when I'm at 6000.
> Still another way is to increase power, and wait until I drift up to 6000,
> then adjust power and retrim. Various other combinations are possible, such
> as adjusting power and/or pitch and/or trim simultaneously, and so on.
>
> Which method do you normally use? Is there a recommended method?
>
> I make a distinction here between initial climbs/descents and extended
> climbs/descents and small altitude changes. I presume it's not necessary to
> worry too much about constant adjustment of mixture or things like that in a
> change of only 2000 feet or so--it can always be adjusted after the target
> altitude is reached. Similarly, although power must ultimately be adjusted
> for any new altitude, it doesn't seem that it's really necessary during the
> altitude change; a slight change in airspeed isn't that big a deal. This
> would seem to leave a lot of room for personal preferences, which is why I ask
> which methods are the most popular, and why.
>
> --
> Transpose mxsmanic and gmail to reach me by e-mail.

It depends on the situation, but for your specific example, of a 4 to
6 kft climb, I would increase power to max, then pitch (and trim) for
about 90 kts. If I had the mixture leaned, I would go to full rich
first (above 75% power, full rich is required for proper engine
cooling). 90 kts is faster than Vy for my Cherokee (about 72-74 kts),
but is recommended for cruise climb since it results in a lower nose
and better forward visibility, and also better engine cooling.

Normally, for a 6 to 4 kft descent, I slightly reduce power and
slightly trim nose down to achieve about a 500 fpm descent at a
slightly higher airspeed. I don't reduce power substantially to
prevent too much engine cooling, and I don't trim nose down too much
to keep airspeed in the green. If the mixture was leaned, I would
enrichen before descending (otherwise mixture could become too lean
for proper engine operation as air density increases during the
descent)

It would be better to not think of altitude changes as "drifting"
around; it's more formal. A climb or descent is a specific maneuver
that follows a defined procedure involving the flight controls and
engine controls. That procedure will be specific to the airplane and
the circumstances.

However, for small altitude corrections (e.g. 100 ft or so), I just
move the yoke, and then nudge the trim a bit to correct for the
altitude drift rate.

[TheSmokingGnu]

Mxsmanic wrote:
> Which one is correct, and why?

The hypothetical, because it lists the required combination of commands.

TheSmokingGnu

Edit: crossposted, corrected.

[BT]

> It depends on the situation, but for your specific example, of a 4 to
> 6 kft climb, I would increase power to max, then pitch (and trim) for
> about 90 kts. If I had the mixture leaned, I would go to full rich
> first (above 75% power, full rich is required for proper engine
> cooling). 90 kts is faster than Vy for my Cherokee (about 72-74 kts),
> but is recommended for cruise climb since it results in a lower nose
> and better forward visibility, and also better engine cooling.
>

For Mr Fly Cherokee.

A full rich climb at those altitudes can result in lower performance. If
your POH engine manual dictates full rich above 75% power.. then I cannot
recommend against following that procedure.

However, At 5Kft MSL, on a hot day at full throttle are you really getting
75% power? The Density Altitude.. ohh.. that bugger we live with in the
west.. could be well above 8Kft MSL. 5K Pressure Altitude, 30C, = 7779
Density Altitude

If you find that climbing through 5Kft MSL your RPMs are dropping off, then
lean to max RPM for max performance of the engine and then bump it rich just
a tad.

BT

[Mxsmanic]

writes:

> It depends on the situation, but for your specific example, of a 4 to
> 6 kft climb, I would increase power to max, then pitch (and trim) for
> about 90 kts. If I had the mixture leaned, I would go to full rich
> first (above 75% power, full rich is required for proper engine
> cooling). 90 kts is faster than Vy for my Cherokee (about 72-74 kts),
> but is recommended for cruise climb since it results in a lower nose
> and better forward visibility, and also better engine cooling.
>
> Normally, for a 6 to 4 kft descent, I slightly reduce power and
> slightly trim nose down to achieve about a 500 fpm descent at a
> slightly higher airspeed. I don't reduce power substantially to
> prevent too much engine cooling, and I don't trim nose down too much
> to keep airspeed in the green. If the mixture was leaned, I would
> enrichen before descending (otherwise mixture could become too lean
> for proper engine operation as air density increases during the
> descent)
>
> It would be better to not think of altitude changes as "drifting"
> around; it's more formal. A climb or descent is a specific maneuver
> that follows a defined procedure involving the flight controls and
> engine controls. That procedure will be specific to the airplane and
> the circumstances.
>
> However, for small altitude corrections (e.g. 100 ft or so), I just
> move the yoke, and then nudge the trim a bit to correct for the
> altitude drift rate.

Thanks for the detailed reply.

I mentioned "drifting" because I was thinking of VFR flight, during which you
might want to move a little higher or lower, for example, while sightseeing.
In that case it wouldn't necessarily be a formal procedure (as far as I know).
If you are under ATC control, of course, you might want to do things a bit
more formally in order to match ATC's expectations.

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

[[email protected]]

> It depends on the situation, but for your specific example...

As a real student pilot (real as in, my feet leave the ground) I would
like to thank FlyCherokee and BT for their informative posts.

Guys, I do appreciate the frustration with Mxsmaniac, but I sometimes
think (having lurked in this group for a while) that you are all a
little too quick to show-off your razor-sharp wit in response to his/
her posts. If you are going to respond, why not do it productively?
Believe me, there are some of us here that do appreciate your
experience and insight. It is even interesting to see how the
experience of real flight conflicts with a simulated experience (the
obvious, of course, being the severity of a 'crash' :o))

I am certain that anyone with the brain power to safely operate an
aircraft, has the ability to keep on topic without being drawn into a
flamewar.... despite Mxsmaniacs 'crosswind' effect.

Thanks.

[Dave[_3_]]

Well stated!

Of all the above, 2 knew the answer and posted proper replies....

Others could not wait to trumpet their attitude... (sigh)

...a lot of noise on this NG, and it is not from MX...

Dave





On 8 Apr 2007 06:16:12 -0700, wrote:

>
>> It depends on the situation, but for your specific example...
>
>As a real student pilot (real as in, my feet leave the ground) I would
>like to thank FlyCherokee and BT for their informative posts.
>
>Guys, I do appreciate the frustration with Mxsmaniac, but I sometimes
>think (having lurked in this group for a while) that you are all a
>little too quick to show-off your razor-sharp wit in response to his/
>her posts. If you are going to respond, why not do it productively?
>Believe me, there are some of us here that do appreciate your
>experience and insight. It is even interesting to see how the
>experience of real flight conflicts with a simulated experience (the
>obvious, of course, being the severity of a 'crash' :o))
>
>I am certain that anyone with the brain power to safely operate an
>aircraft, has the ability to keep on topic without being drawn into a
>flamewar.... despite Mxsmaniacs 'crosswind' effect.
>
>Thanks.

[[email protected]]

On Apr 8, 8:36 am, Mxsmanic > wrote:
>
> I mentioned "drifting" because I was thinking of VFR flight, during which you
> might want to move a little higher or lower, for example, while sightseeing.
> In that case it wouldn't necessarily be a formal procedure (as far as I know).
> If you are under ATC control, of course, you might want to do things a bit
> more formally in order to match ATC's expectations.
>
Ok, I see. "Formal" was probably not a good word choice by me, I
didn't mean formal in the regulatory, or ATC sense, but rather in the
sense of the somewhat abstract concept of "good airmanship".
Changing altitude during cruise is a deliberate maneuver with a
defined procedure and checklist. Exercising good airmanship means you
would follow that procedure.

Even when VFR sightseeing, or otherwise just noodling around in the
local area, following the POH procedure for extended climbs is
important for the health of the engine.

[BT]

I merely wanted to speak about full rich full power climbs mentioned by Mr
Cherokee... many POH suggest leaning for max power take offs at high DA
airports... why should the DA airport make any difference than climbing at
high DA altitudes... you still want performance from the engine.. while
keeping the engine safe from overheating

I did not intend to answer MX

BT

> wrote in message
oups.com...
>
>> It depends on the situation, but for your specific example...
>
> As a real student pilot (real as in, my feet leave the ground) I would
> like to thank FlyCherokee and BT for their informative posts.
>
> Guys, I do appreciate the frustration with Mxsmaniac, but I sometimes
> think (having lurked in this group for a while) that you are all a
> little too quick to show-off your razor-sharp wit in response to his/
> her posts. If you are going to respond, why not do it productively?
> Believe me, there are some of us here that do appreciate your
> experience and insight. It is even interesting to see how the
> experience of real flight conflicts with a simulated experience (the
> obvious, of course, being the severity of a 'crash' :o))
>
> I am certain that anyone with the brain power to safely operate an
> aircraft, has the ability to keep on topic without being drawn into a
> flamewar.... despite Mxsmaniacs 'crosswind' effect.
>
> Thanks.
>

[BT]

Thanx Dave... now we wait for MXs inevitable counter replies.. I made the
error and got into many debates, if he does not get "his" answer.. he keeps
pushing and not accepting the advice of many with 30+yrs experience. I will
comment on other inputs.. but I will not answer MX.

It seems he is a walking... wait.. sitting wikepedia... on so many topics...
remember that wikepedia is written by less than average people with
something to say... yes there is knowledge there... not to discount
wikepedia.. but it is un moderated.

BT

"Dave" > wrote in message
...
> Well stated!
>
> Of all the above, 2 knew the answer and posted proper replies....
>
> Others could not wait to trumpet their attitude... (sigh)
>
> ..a lot of noise on this NG, and it is not from MX...
>
> Dave
>
>
>
>
>
> On 8 Apr 2007 06:16:12 -0700, wrote:
>
>>
>>> It depends on the situation, but for your specific example...
>>
>>As a real student pilot (real as in, my feet leave the ground) I would
>>like to thank FlyCherokee and BT for their informative posts.
>>
>>Guys, I do appreciate the frustration with Mxsmaniac, but I sometimes
>>think (having lurked in this group for a while) that you are all a
>>little too quick to show-off your razor-sharp wit in response to his/
>>her posts. If you are going to respond, why not do it productively?
>>Believe me, there are some of us here that do appreciate your
>>experience and insight. It is even interesting to see how the
>>experience of real flight conflicts with a simulated experience (the
>>obvious, of course, being the severity of a 'crash' :o))
>>
>>I am certain that anyone with the brain power to safely operate an
>>aircraft, has the ability to keep on topic without being drawn into a
>>flamewar.... despite Mxsmaniacs 'crosswind' effect.
>>
>>Thanks.
>

[[email protected]]

On Apr 7, 11:00 pm, "BT" > wrote:
> > It depends on the situation, but for your specific example, of a 4 to
> > 6 kft climb, I would increase power to max, then pitch (and trim) for
> > about 90 kts. If I had the mixture leaned, I would go to full rich
> > first (above 75% power, full rich is required for proper engine
> > cooling). 90 kts is faster than Vy for my Cherokee (about 72-74 kts),
> > but is recommended for cruise climb since it results in a lower nose
> > and better forward visibility, and also better engine cooling.
>
> For Mr Fly Cherokee.
>
> A full rich climb at those altitudes can result in lower performance. If
> your POH engine manual dictates full rich above 75% power.. then I cannot
> recommend against following that procedure.
>
> However, At 5Kft MSL, on a hot day at full throttle are you really getting
> 75% power? The Density Altitude.. ohh.. that bugger we live with in the
> west.. could be well above 8Kft MSL. 5K Pressure Altitude, 30C, = 7779
> Density Altitude
>
> If you find that climbing through 5Kft MSL your RPMs are dropping off, then
> lean to max RPM for max performance of the engine and then bump it rich just
> a tad.
>
> BT

Yes, you are quite right, density altitude is the key parameter. I
have one of those ancient Cherokees with the pamphlet-style POH.
There's not a lot in there, but they do say full rich over 75% power,
which as I recall, is about 8 kft density altitude at full throttle.

In any event, I've always been a bit conservative when it comes to
leaning, I tend to err on the too-rich side, thinking that I'm helping
the engine.

[BT]

>> If you find that climbing through 5Kft MSL your RPMs are dropping off,
>> then
>> lean to max RPM for max performance of the engine and then bump it rich
>> just
>> a tad.
>>
>> BT
>
> Yes, you are quite right, density altitude is the key parameter. I
> have one of those ancient Cherokees with the pamphlet-style POH.
> There's not a lot in there, but they do say full rich over 75% power,
> which as I recall, is about 8 kft density altitude at full throttle.
>
> In any event, I've always been a bit conservative when it comes to
> leaning, I tend to err on the too-rich side, thinking that I'm helping
> the engine.
>

Mr Cherokee, I understand the problems with 1960-70s style POHs.
There have been some excellent articles in recent aviation magazines on
engine leaning, granted those procedures are best accomplished with added
engine monitoring instruments.

We fly a 1965 Piper Pawnee with 250HP (Lyc O-540) carbureted fixed pitch
configuration in glider towing operations. The airport is 2833MSL. Winter,
not many problems.. summer.. we are leaning as soon as we break ground for
max RPM. The mixture naturally gets richer as we climb after leaning due to
the climb, so we most always end up rich of peak and constantly monitor for
rpm drop with the richer mixture and then lean some more.

The mixture setting reached at altitude is left alone all the way back to
the ground.. lower power settings.. and is also used for ground idle if the
engine will idle without stumbling at that setting. Mixture is enriched for
go around or take off, until the engine gets up to speed and we are climbing
again. Oil temps are monitored, we do not have CHT or EGT gauges. Oil temp
in winter avgs about 180-190F, summer about 210F. We have two oil coolers
and change oil every 50hrs. We average about 250hrs per year on the engine
with weekend only operations.

BT

[Peter Dohm]

"BT" > wrote in message
...
> I merely wanted to speak about full rich full power climbs mentioned by Mr
> Cherokee... many POH suggest leaning for max power take offs at high DA
> airports... why should the DA airport make any difference than climbing at
> high DA altitudes... you still want performance from the engine.. while
> keeping the engine safe from overheating
>
---------remainder snipped-------

At the moment, I can't seem to lay hands on my meager collection of POHs,
but my recollection is that the issue of climbing at high density altitude
was covered indirectly. The aircraft for which I had/have a POH all had
fixed pitch props and, IIRC, all mentioned some density altitude above which
the engine should be leaned to peak rpm when cruising at full throttle.

Inasmuch as the rpm might decrease in a full throttle climbe at best rate of
climb airspeed, it is possible that the recommended minimum altitude for
leaning to peak rpm might be different, and this *may* have been addressed
as well. Basically, it is usually based on 75% power; but I just don't know
enough to assert that both both altitudes are really one and the same.

A call to customer support at the airframe and/or engine manufacturer might
yeild some excellent insight. Of course, if they provide references to
where the information is readily available, please post the reference--I am
sure that I am not the only reader of this NG who's research could use some
help from time to time.

Peter

[Maxwell]

"Nomen Nescio" > wrote in message
...
> -----BEGIN PGP SIGNED MESSAGE-----
>
> From:
>
>>It depends on the situation, but for your specific example, of a 4 to
>>6 kft climb, I would increase power to max, then pitch (and trim) for
>>about 90 kts.
>
> DAMMIT!!
> Just when it was starting to look like everyone had wised up and
> wouldn't waste time on giving the idiot, simmer, arrogant loser,
> douchebag, an answer. You just gotta show up and post this.
> I guess Mxsmoron will be here for another month.
>
> DAMN YOU!
> WHY?
> WHY?
> WHY?
>

I think everyone has wised up a good bit. At least those with any brains.
What we might be seeing here is either sock puppet time, or just MX talking
to himself. There sure seems to be no shortage of gmail accounts in there.

Probably would hurt if more of us, me included, watched more closely for
MX's attempts to cross post his trolls over to .student and .sim and alike
to draw in non pilots for seasoning and sock puppeting.

Just a suggestion to the 95% of the people here I have come to seriously
respect. But I would be happy to hear anyone's thoughts, either here or on
direct.

[Maxwell]

"Dave" > wrote in message
...
> Well stated!
>
> Of all the above, 2 knew the answer and posted proper replies....
>
> Others could not wait to trumpet their attitude... (sigh)
>
> ..a lot of noise on this NG, and it is not from MX...
>
> Dave
>

I'd have to disagree. ANY student pilot that didn't know the answer to that
question needs to be looking for a new flight instructor. No one was posting
answers, because they didn't want to feed the troll.

[Maxwell]

"BT" > wrote in message
...
>I merely wanted to speak about full rich full power climbs mentioned by Mr
>Cherokee... many POH suggest leaning for max power take offs at high DA
>airports... why should the DA airport make any difference than climbing at
>high DA altitudes... you still want performance from the engine.. while
>keeping the engine safe from overheating
>
> I did not intend to answer MX


No problem. Just reframe your question and start a new post.

[[email protected]]

I have a memory of taking off from Grand Canyon Airport in a Mooney
201 in the summer and the density altitude had to be 9000 feet. I had
to lean at full throttle to get reasonable power in that circumstance.
I was getting pulled around the sky by an IO 360.

I don't remember the POH instructions for those conditions but sure
know how read RPMs and CHTs and treat engines with TLC.





On Apr 8, 7:23 pm, "Maxwell" > wrote:
> "BT" > wrote in message
>
> ...
>
> >I merely wanted to speak about full rich full power climbs mentioned by Mr
> >Cherokee... many POH suggest leaning for max power take offs at high DA
> >airports... why should the DA airport make any difference than climbing at
> >high DA altitudes... you still want performance from the engine.. while
> >keeping the engine safe from overheating
>
> > I did not intend to answer MX
>
> No problem. Just reframe your question and start a new post.

[ManhattanMan]

Maxwell wrote:
>
> I think everyone has wised up a good bit. At least those with any
> brains. What we might be seeing here is either sock puppet time, or
> just MX talking to himself. There sure seems to be no shortage of
> gmail accounts in there.
> Probably would hurt if more of us, me included, watched more closely
> for MX's attempts to cross post his trolls over to .student and .sim
> and alike to draw in non pilots for seasoning and sock puppeting.
>
> Just a suggestion to the 95% of the people here I have come to
> seriously respect. But I would be happy to hear anyone's thoughts,
> either here or on direct.

Not sure WHY, but it does seem the troll seems to attract the same "serious"
respondents a majority of the time - which only "innocently" starts the fire
that turns into a out of control blaze. Just an observation...

[BDS]

> Maxwell wrote:

> > Just a suggestion to the 95% of the people here I have come to
> > seriously respect. But I would be happy to hear anyone's thoughts,
> > either here or on direct.

My thoughts are simply this - stop reading the guy if he bothers you that
much.

Seems like the loudest complainers are the ones anxiously awaiting his next
post in hopes that there will be some minor glitch they can jump on and
point out. Then the ridiculous back and forth ensues where something like
the definition of the word "is" is debated ad nauseum.

Why is that any worse than reading a week's worth of "tower induced go
around" arguments?

BDS

[Maxwell]

"BDS" > wrote in message
...
>> Maxwell wrote:
>
>> > Just a suggestion to the 95% of the people here I have come to
>> > seriously respect. But I would be happy to hear anyone's thoughts,
>> > either here or on direct.
>
> My thoughts are simply this - stop reading the guy if he bothers you that
> much.
>
> Seems like the loudest complainers are the ones anxiously awaiting his
> next
> post in hopes that there will be some minor glitch they can jump on and
> point out. Then the ridiculous back and forth ensues where something like
> the definition of the word "is" is debated ad nauseum.
>
> Why is that any worse than reading a week's worth of "tower induced go
> around" arguments?
>
> BDS
>
>

The difference in a topic you might not be personally interested in - and a
jackass dedicated to nothing more than discouraging valuable and experienced
contributors, while ****ing out potentally fatal advice to those who may
actually not know the difference.

[Morgans[_2_]]

"BDS" > wrote

> Why is that any worse than reading a week's worth of "tower induced go
> around" arguments?

I quit reading that one, after just a few days.

IMHO, Stephen reached a new low of pointless argument. Enough so, that I
won't be participating in any of his arguments, for a good long while to
come.

As for the other argument making insulting troll, I fail to see any point in
anyone participating with his threads, but yet they do.

Go figure.
--
Jim in NC

[BDS]

"Maxwell" > wrote
>
> The difference in a topic you might not be personally interested in - and
a
> jackass dedicated to nothing more than discouraging valuable and
experienced
> contributors, while ****ing out potentally fatal advice to those who may
> actually not know the difference.

I understand where you're coming from and I can only offer this: as to the
first part, anyone who has spent any time here at all knows exactly what to
expect from the guy, and where it comes from as far as background goes.

As to the potentially fatal advice, I wouldn't worry about that too much for
reasons I mentioned above, and also because I think that people are
generally smart enough to know how much weight to put on advice they get on
the internet.

I guess I'm just surprised that so many people appear to feel so threatened
by him. So much so that in some cases they just up and leave. Weird.

BDS

[tony roberts]

In article >,
MXMORON > wrote:

> From what you've shown here, your attitude cannot be changed.


You all think that you are funny - God knows why :(
Can we please, please, please give it a rest,
You are most definitely not funny or entertaining - or even original!
Mxsmanic is actually more interesting than your pathetic responses.
Can't you see that?

Can we please have a rest from this absolute crap?

Thanks in advance.

Tony
--

Tony Roberts
PP-ASEL
VFR OTT
Night
Cessna 172H C-GICE

[Maxwell]

"BDS" > wrote in message
...
> "Maxwell" > wrote
>>
>> The difference in a topic you might not be personally interested in - and
> a
>> jackass dedicated to nothing more than discouraging valuable and
> experienced
>> contributors, while ****ing out potentally fatal advice to those who may
>> actually not know the difference.
>
> I understand where you're coming from and I can only offer this: as to the
> first part, anyone who has spent any time here at all knows exactly what
> to
> expect from the guy, and where it comes from as far as background goes.

No, sorry, but from my perspective you don't understand his impact on this
group at all.

>
> As to the potentially fatal advice, I wouldn't worry about that too much
> for
> reasons I mentioned above, and also because I think that people are
> generally smart enough to know how much weight to put on advice they get
> on
> the internet.

That's seldom if ever a problem on the Usenet, until the trolls have
eliminated the participation of experienced contributors. Then you have
nothing left but a useless message board for children.

>
> I guess I'm just surprised that so many people appear to feel so
> threatened
> by him. So much so that in some cases they just up and leave. Weird.
>

That is exactly the point. We hold in our hands a forum, truly an
encyclopedia, that will answer typed questions with expert conclusions.
These threads as they are called, are crossed check for accuracy by dozens
of not hundreds of EXPERTS daily, something that is as reliable as anything
you will find for precise and accurate advice. And these experts will go to
great lengths to explain very intricate concepts to you, until even the
layman can understand them. Now what is the value of that forum? And where
can you find anything better, at any price?

So the problem is, the forum is useless without those experts. And after a
few months or years, those experts will leave. Simply because they are tired
of trying in vain to explain their contribution to someone that just repays
them by arguing with the reality they choose not to believe, because it
interferes with their personal wishes and fantasy.

Although I don't know you, and certainly don't want to argue with you, I can
only suggest based on the comments in your post, that you have no idea of
the many years of experience and wealth of knowledge of the people that
surround you. And this group will suffer every time each and every one of
them tire and leave.

So if simulator only folks wish to ask questions here, super. No one here
cares about the qualifications of someone posing a question. But when
someone starts handing out advice, it's going to be checked. The is nature
and power of the forum. Don't give advice unless you are willing to have it
questioned. And don't argue with the experienced people that offer
corrections. Without them, it's just another AOL chat room for kids.

[Blanche]

As a rule, I respond only once to MX, never to other obvious trolls.
Why? Because the initial question from MX is often reasonable. So he
gets a reasonable answer - when I think I'm qualified to answer it.
I do not respond to him again.

This way, I think I offer legitimate information to others with
the same question without having to participate in the troll-bashing.

(ref. Jeppesen discussion - I offered explanation of the internal
workings of Jepp, then quit, merely watching the ensuing stupidity)

[Morgans[_2_]]

"Blanche" > wrote in message
...
> As a rule, I respond only once to MX, never to other obvious trolls.
> Why? Because the initial question from MX is often reasonable. So he
> gets a reasonable answer - when I think I'm qualified to answer it.
> I do not respond to him again.
>
> This way, I think I offer legitimate information to others with
> the same question without having to participate in the troll-bashing.
>
> (ref. Jeppesen discussion - I offered explanation of the internal
> workings of Jepp, then quit, merely watching the ensuing stupidity)

Problem is, if there are 50 people like you who feel he can get a reasonable
answer from you, you get 50 posts, to someone who will (with out a doubt,
proven time after time) turn the discussion to stupidity.

IF nobody were to answer, reasonable answer or not, after a time he would
leave, and take his stupidity with him.

By the way, you cast your pearls among swine, when you give him an answer.
He really does not want to know.

Let someone else ask the question.
--
Jim in NC

[Maxwell]

"Morgans" > wrote in message
...
>
> "Blanche" > wrote in message
> ...
>> As a rule, I respond only once to MX, never to other obvious trolls.
>> Why? Because the initial question from MX is often reasonable. So he
>> gets a reasonable answer - when I think I'm qualified to answer it.
>> I do not respond to him again.
>>
>> This way, I think I offer legitimate information to others with
>> the same question without having to participate in the troll-bashing.
>>
>> (ref. Jeppesen discussion - I offered explanation of the internal
>> workings of Jepp, then quit, merely watching the ensuing stupidity)
>
> Problem is, if there are 50 people like you who feel he can get a
> reasonable answer from you, you get 50 posts, to someone who will (with
> out a doubt, proven time after time) turn the discussion to stupidity.
>
> IF nobody were to answer, reasonable answer or not, after a time he would
> leave, and take his stupidity with him.
>
> By the way, you cast your pearls among swine, when you give him an answer.
> He really does not want to know.
>
> Let someone else ask the question.
> --
> Jim in NC
>

I pretty much agree with all above, but I don't think you will ever get
people to stop posting. With new people arriving daily (which is very good)
and old contributors checking in from time to time, MX will always have a
source of victims that don't know him. And his MO is to exploit peoples
natural tendency to be helpful.

I personally think the only possible solution is to not give him straight
answers. He's not asking straight questions. Most all are broadly
structured in a way to create endless chaos. He even delights in confusing
the discussions by addressing issues in a different branches of a thread as
it naturally parts in to sub interests. Simply to avoid the usual
conclusion, the he himself has given bad advice or misquoted himself.

As long as he can con anyone in to feeding his thread with any related
information, or fool us with sock puppets, answering his own questions under
a different moniker, and cross posting to encourage unrelated (and
unsuspecting) visitors from other forums, he will create discontent. I
firmly believe it is his only purpose. He is merely a troll.

So if you can't refrain from answering, fine - just don't offer information
that will help feed his thread. If a legitimate question comes to anyone's
mind, simply reframe the question and start a new post under your own name.

But this is just a suggestion, I'm not trying to insist I'm right or control
anyone's input to the Usenet. But it is the only solution I can see.

[EridanMan]

I suggest you read through:
www.av8n.com

a very good discussion of energy management in aircraft.

http://www.av8n.com/how/htm/energy.html#sec-controls-energy

This section discusses the effect of various controls on an aircraft
(power/pitch, etc). The entire website is a worthwhile read, however.

The short answer to your question is that pitch climbing is fast,
imprecise, and tends to throw the aircraft way out of trim. Power
adjustments on the other hand are rather slow, tremendously precise,
and allow the aircraft to remain stabilized in the same configuration.

[Peter Dohm]

> I suggest you read through:
> www.av8n.com
>
> a very good discussion of energy management in aircraft.
>
> http://www.av8n.com/how/htm/energy.html#sec-controls-energy
>
> This section discusses the effect of various controls on an aircraft
> (power/pitch, etc). The entire website is a worthwhile read, however.
>
> The short answer to your question is that pitch climbing is fast,
> imprecise, and tends to throw the aircraft way out of trim. Power
> adjustments on the other hand are rather slow, tremendously precise,
> and allow the aircraft to remain stabilized in the same configuration.
>
>
At a glance, that looks like an excellent discussion of the subject.

Peter

[Mxsmanic]

EridanMan writes:

> I suggest you read through:
> www.av8n.com
>
> a very good discussion of energy management in aircraft.
>
> http://www.av8n.com/how/htm/energy.html#sec-controls-energy

Thanks. I've visited that site before; the author becomes very abstract at
times, but it is useful information.

> The short answer to your question is that pitch climbing is fast,
> imprecise, and tends to throw the aircraft way out of trim.

By pitch climbing do you mean with the yoke, or with trim adjustments?

> Power adjustments on the other hand are rather slow, tremendously precise,
> and allow the aircraft to remain stabilized in the same configuration.

If I have nose-down trim applied to go fast at my low altitude, it seems I
should be able to trim slightly upwards and change altitude easily, then trim
back for level flight at the new altitude. If I already have nose-up trim
applied, this may not work, and eventually I'll have to add power.

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

[mike regish]

The really ironic thing here is that the people complaining about Mx are the
ones that are actually guilty of what they are accusing Mx of. And they're
too freakin' stupid to realize it.

Do a message count and see just where the noise is coming from.

mike

"tony roberts" > wrote in message
news:indiacharlieecho-0E36E4.20490808042007@shawnews...
> In article >,
> MXMORON > wrote:
>
>> From what you've shown here, your attitude cannot be changed.
>
>
> You all think that you are funny - God knows why :(
> Can we please, please, please give it a rest,
> You are most definitely not funny or entertaining - or even original!
> Mxsmanic is actually more interesting than your pathetic responses.
> Can't you see that?
>
> Can we please have a rest from this absolute crap?
>
> Thanks in advance.
>
> Tony
> --
>
> Tony Roberts
> PP-ASEL
> VFR OTT
> Night
> Cessna 172H C-GICE

[JGalban via AviationKB.com]

Peter Dohm wrote:
>
>Inasmuch as the rpm might decrease in a full throttle climbe at best rate of
>climb airspeed, it is possible that the recommended minimum altitude for
>leaning to peak rpm might be different, and this *may* have been addressed
>as well. Basically, it is usually based on 75% power; but I just don't know
>enough to assert that both both altitudes are really one and the same.
>

You hit the nail on the head. Leaning at wide open throttle will be done
at a lower altitude for a climb than for cruise. That's due to the lower rpm
you'll get while climbing. In level flight, the engine (assuming normally
aspirated, fixed pitch) will produce 75% up to 7.5K - 8K ft. In a climb, you
can lean at a lower DA because the prop load will keep the engine from
turning as fast as it would in a level cruise altitude.

The manual for my '68 Cherokee includes the recommendation to lean for max
rpm on a climbout from 5K ft. DA or higher. The Power vs. Density altitude
chart provides guidance for cruise settings at altitude.

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

--
Message posted via AviationKB.com
http://www.aviationkb.com/Uwe/Forums.aspx/aviation/200704/1

[Morgans[_2_]]

"Danny Deger" > wrote

> Good policy. Respond once and only once. And don't participate in the
> massive MX flaming that is the real source of this group getting plugged
> up with garbage. To you MX flammers out there -- please stop.

Once is once too much.

With the number of active posters in this group, if only half of them post,
that is too much ammunition to give him to argue with. Why answer at all,
when you know eventually, he will twist it and discount it _and_ the poster
is some manner. You KNOW he will. It is his constant.
--
Jim in NC

[Danny Deger]

"Mxsmanic" > wrote in message
...
> Suppose you're in your small aircraft and you want to climb from 4000 to
> 6000,
> or descend from 6000 to 4000. What method do you use? I can think of
> several, but I don't know which is best/recommended.
>
> For example, to climb from 4000 to 6000, I can just ease the yoke back and
> climb. When I get to 6000, I can adjust power and retrim. Another way is
> to
> just add some nose-up trim, then retrim and adjust power when I'm at 6000.
> Still another way is to increase power, and wait until I drift up to 6000,
> then adjust power and retrim. Various other combinations are possible,
> such
> as adjusting power and/or pitch and/or trim simultaneously, and so on.
>
> Which method do you normally use? Is there a recommended method?
>
> I make a distinction here between initial climbs/descents and extended
> climbs/descents and small altitude changes. I presume it's not necessary
> to
> worry too much about constant adjustment of mixture or things like that in
> a
> change of only 2000 feet or so--it can always be adjusted after the target
> altitude is reached. Similarly, although power must ultimately be
> adjusted
> for any new altitude, it doesn't seem that it's really necessary during
> the
> altitude change; a slight change in airspeed isn't that big a deal. This
> would seem to leave a lot of room for personal preferences, which is why I
> ask
> which methods are the most popular, and why.
>
> --
> Transpose mxsmanic and gmail to reach me by e-mail.

For small climbs, I usually add power and trim to a slightly lower airspeed.
For small decents, I usually just reduce power and leave the trim/airspeed
alone.

Danny Deger

[Danny Deger]

"Dave" > wrote in message
...
> Well stated!
>
> Of all the above, 2 knew the answer and posted proper replies....
>
> Others could not wait to trumpet their attitude... (sigh)
>
> ..a lot of noise on this NG, and it is not from MX...
>
> Dave
>
>
>
>
>
> On 8 Apr 2007 06:16:12 -0700, wrote:
>
>>
>>> It depends on the situation, but for your specific example...
>>
>>As a real student pilot (real as in, my feet leave the ground) I would
>>like to thank FlyCherokee and BT for their informative posts.
>>
>>Guys, I do appreciate the frustration with Mxsmaniac, but I sometimes
>>think (having lurked in this group for a while) that you are all a
>>little too quick to show-off your razor-sharp wit in response to his/
>>her posts. If you are going to respond, why not do it productively?
>>Believe me, there are some of us here that do appreciate your
>>experience and insight. It is even interesting to see how the
>>experience of real flight conflicts with a simulated experience (the
>>obvious, of course, being the severity of a 'crash' :o))
>>
>>I am certain that anyone with the brain power to safely operate an
>>aircraft, has the ability to keep on topic without being drawn into a
>>flamewar.... despite Mxsmaniacs 'crosswind' effect.
>>
>>Thanks.
>

I agree 100%. I have no problems reading his posts or ligit responses. It
is the contant flaming of MX that is clogging up this newsgroup. Let me
repeat this. It is the flaming of MX that is the problem here!!!

Danny Deger

[Danny Deger]

"BT" > wrote in message
...
>I merely wanted to speak about full rich full power climbs mentioned by Mr
>Cherokee... many POH suggest leaning for max power take offs at high DA
>airports... why should the DA airport make any difference than climbing at
>high DA altitudes... you still want performance from the engine.. while
>keeping the engine safe from overheating

snip

If you are confused by when to lean, do what I did -- buy a 40's plane that
has no mixture control :-)

Danny Deger
>
>

[Danny Deger]

"Blanche" > wrote in message
...
> As a rule, I respond only once to MX, never to other obvious trolls.
> Why? Because the initial question from MX is often reasonable. So he
> gets a reasonable answer - when I think I'm qualified to answer it.
> I do not respond to him again.
>
> This way, I think I offer legitimate information to others with
> the same question without having to participate in the troll-bashing.
>

Good policy. Respond once and only once. And don't participate in the
massive MX flaming that is the real source of this group getting plugged up
with garbage. To you MX flammers out there -- please stop.

Danny Deger

[Danny Deger]

"Morgans" > wrote in message
...
>
> "Blanche" > wrote in message
> ...
>> As a rule, I respond only once to MX, never to other obvious trolls.
>> Why? Because the initial question from MX is often reasonable. So he
>> gets a reasonable answer - when I think I'm qualified to answer it.
>> I do not respond to him again.
>>
>> This way, I think I offer legitimate information to others with
>> the same question without having to participate in the troll-bashing.
>>
>> (ref. Jeppesen discussion - I offered explanation of the internal
>> workings of Jepp, then quit, merely watching the ensuing stupidity)
>
> Problem is, if there are 50 people like you who feel he can get a
> reasonable answer from you, you get 50 posts, to someone who will (with
> out a doubt, proven time after time) turn the discussion to stupidity.
>
> IF nobody were to answer, reasonable answer or not, after a time he would
> leave, and take his stupidity with him.
>
> By the way, you cast your pearls among swine, when you give him an answer.
> He really does not want to know.
>

I disagree. I find his questions very reasonable and I believe he wants to
know. I also believe many that read his posts and the replies will learn
something about flying.

I do agree that I don't like the fact he will argue with a senior pilot of a
747 about how to fly a 747 and recommend not arguing online with him. But I
also have NEVER read a post from him where he insults the poster. I must
say I am amazed he has not considering the nature of insults we have thrown
at him.

One thing I am certain of thing, flaming him will not make him go away. I
suspect he has visited the warez groups (i.e. competer hackers) where
flaming is an art form. Where ever he gets it, he is like I am -- flaming
does not bother us in the least.

Danny Deger

[Danny Deger]

"mike regish" > wrote in message
. ..
> The really ironic thing here is that the people complaining about Mx are
> the ones that are actually guilty of what they are accusing Mx of. And
> they're too freakin' stupid to realize it.
>
> Do a message count and see just where the noise is coming from.
>
> mike
>
> "tony roberts" > wrote in message
> news:indiacharlieecho-0E36E4.20490808042007@shawnews...
>> In article >,
>> MXMORON > wrote:
>>
>>> From what you've shown here, your attitude cannot be changed.
>>
>>
>> You all think that you are funny - God knows why :(
>> Can we please, please, please give it a rest,
>> You are most definitely not funny or entertaining - or even original!
>> Mxsmanic is actually more interesting than your pathetic responses.
>> Can't you see that?
>>
>> Can we please have a rest from this absolute crap?
>>
>> Thanks in advance.
>>
>> Tony
>> --
>>
>> Tony Roberts
>> PP-ASEL
>> VFR OTT
>> Night
>> Cessna 172H C-GICE
>
>

I agree with Tony and Mike. I don't mind MX. I do mind the countless
emails written to flame him. I have NEVER read an email from MX flaming
anyone. Yes, I have read where he tells a senior 747 pilot how to fly a
747, but never an insult to a person.

Danny Deger

[Bertie the Bunyip]

On 9 Apr, 23:10, Mxsmanic > wrote:
> EridanMan writes:
> > I suggest you read through:
> >www.av8n.com
>
> > a very good discussion of energy management in aircraft.
>
> >http://www.av8n.com/how/htm/energy.html#sec-controls-energy
>
> Thanks. I've visited that site before; the author becomes very abstract at
> times, but it is useful information.
>
> > The short answer to your question is that pitch climbing is fast,
> > imprecise, and tends to throw the aircraft way out of trim.
>
> By pitch climbing do you mean with the yoke, or with trim adjustments?
>
> > Power adjustments on the other hand are rather slow, tremendously precise,
> > and allow the aircraft to remain stabilized in the same configuration.
>
> If I have nose-down trim applied to go fast at my low altitude,

You don't have "altitude" you don't fly, fjukkwit.



Bertie

[EridanMan]

> Thanks. I've visited that site before; the author becomes very abstract at
> times, but it is useful information.

Personally, as an engineer and generally 'theoretical' guy, I enjoy
the abstraction... but I understand what you're saying.

> By pitch climbing do you mean with the yoke, or with trim adjustments?

Yoke. Changing pitch attitude almost always induces phugoid
oscillations, with the yoke, those oscillations are trivial (almost
subconscious) to damp. Trim provides no such mechanism (without
grabbing the yoke anyways), so its generally a bad idea to fly with
it.

For any pitch attitude change, the general rule of thumb is pitch,
power, trim off pressure as necessary, in that order.

> If I have nose-down trim applied to go fast at my low altitude, it seems I
> should be able to trim slightly upwards and change altitude easily, then trim
> back for level flight at the new altitude. If I already have nose-up trim
> applied, this may not work, and eventually I'll have to add power.

It sounds like you're trying to fight the simulated phugoid
oscillation by using trim to make very low amplitude adjustments...
This just increases the period of the oscillations, it in no way
prevents them from occurring.

Power is a good, 'side effect free' mechanism of doing fine trimming
of your aircraft's altitude. In fact, I know instructors who advocate
only ever using the power to make the final 'lock' onto a new cruise
altitude, no matter what.

For example, the mechanism you would use to level off from a cruise
climb would be as follows:

500 feet below target altitude, push the nose forward gently to bring
airspeed up to cruise airspeed. Once you've reached cruise airspeed,
go ahead and trim to hold the attitude, but allow your power surplus
to continue pulling you up the last hundred feet or so to your target
altitude, only backing off the power the moment you reach it.

The descend-to-altitude is the same procedure, only with reduced power
instead (set up the aircraft in cruise attitude before you hit your
target altitude at a reduced descent power setting, and allow the
aircraft to settle onto target altitude before increasing power back
to cruise power)

I can see the theoretical advantages to this approach, but I would be
lying if I said I used to religiously (I still don't keep that far
ahead of the aircraft).

[Paul kgyy]

On Apr 7, 8:11 am, Mxsmanic > wrote:
> Suppose you're in your small aircraft and you want to climb from 4000 to 6000,

As with all things aviation, it depends.

Under IFR, they like you to climb quickly, at least 500 fpm. That
often requires mixture rich, maybe rpm increase, plus more manifold
pressure via throttle (unless you're already maxed out above 5000 ft).

On the other hand, if you've been yakking with a passenger and
suddenly realize you're 200 ft low, just pull the yoke.

For serious climbing, use power and rich mixture, then reduce MP,
prop, and mixture as needed at desired altitude.

[Danny Deger]

"EridanMan" > wrote in message
ups.com...
snip

> Yoke. Changing pitch attitude almost always induces phugoid
> oscillations, with the yoke, those oscillations are trivial (almost
> subconscious) to damp. Trim provides no such mechanism (without
> grabbing the yoke anyways), so its generally a bad idea to fly with
> it.
>

You bring up a good point on phugoids. I have flown everything from J-3
cubs to F-4E (but no heavy time) and the difference in phugoid tendancy is
HUGE. On the Air Force jets, the trim in on the stick, so I didn't fly just
trim. I am currently flying a Taylorcraft which must have a highly damped
phugoid. I find I can fly it with only trim to make gradual changes in
altitude. In other planes, this can't be done as you mention.

Danny Deger

> For any pitch attitude change, the general rule of thumb is pitch,
> power, trim off pressure as necessary, in that order.
>
>> If I have nose-down trim applied to go fast at my low altitude, it seems
>> I
>> should be able to trim slightly upwards and change altitude easily, then
>> trim
>> back for level flight at the new altitude. If I already have nose-up
>> trim
>> applied, this may not work, and eventually I'll have to add power.
>
> It sounds like you're trying to fight the simulated phugoid
> oscillation by using trim to make very low amplitude adjustments...
> This just increases the period of the oscillations, it in no way
> prevents them from occurring.
>
> Power is a good, 'side effect free' mechanism of doing fine trimming
> of your aircraft's altitude. In fact, I know instructors who advocate
> only ever using the power to make the final 'lock' onto a new cruise
> altitude, no matter what.
>
> For example, the mechanism you would use to level off from a cruise
> climb would be as follows:
>
> 500 feet below target altitude, push the nose forward gently to bring
> airspeed up to cruise airspeed. Once you've reached cruise airspeed,
> go ahead and trim to hold the attitude, but allow your power surplus
> to continue pulling you up the last hundred feet or so to your target
> altitude, only backing off the power the moment you reach it.
>
> The descend-to-altitude is the same procedure, only with reduced power
> instead (set up the aircraft in cruise attitude before you hit your
> target altitude at a reduced descent power setting, and allow the
> aircraft to settle onto target altitude before increasing power back
> to cruise power)
>
> I can see the theoretical advantages to this approach, but I would be
> lying if I said I used to religiously (I still don't keep that far
> ahead of the aircraft).
>

[Mxsmanic]

EridanMan writes:

> It sounds like you're trying to fight the simulated phugoid
> oscillation by using trim to make very low amplitude adjustments...

I try it sometimes, on the theory that the more precise changes possible with
tiny bits of trim might prevent me from overcorrecting, whereas gross movement
of the yoke seems more likely to take me past the correct adjustment.

> This just increases the period of the oscillations, it in no way
> prevents them from occurring.

If the period becomes long enough, the oscillation is gone for all effective
purposes.

Sometimes I cheat and turn on the autopilot to trim out the oscillations. I
also sometimes use the autopilot to trim and then adjust power until the AP is
giving me neutral trim (which gives me more trim authority and hopefully
reduces drag, although it also means that I can't necessarily fly at high
speeds).

> Power is a good, 'side effect free' mechanism of doing fine trimming
> of your aircraft's altitude. In fact, I know instructors who advocate
> only ever using the power to make the final 'lock' onto a new cruise
> altitude, no matter what.

See above. I've also tried setting neutral trim (in steps or in one
adjustment) and then using power to find a setting that will keep me at the
desired altitude with that trim. It seems to be more difficult but the
aircraft is very stable once in that configuration.

> 500 feet below target altitude, push the nose forward gently to bring
> airspeed up to cruise airspeed. Once you've reached cruise airspeed,
> go ahead and trim to hold the attitude, but allow your power surplus
> to continue pulling you up the last hundred feet or so to your target
> altitude, only backing off the power the moment you reach it.

That sounds like a plan. I don't know if I've tried it (I may have done so
unconsciously, but I'll have to try it explicitly).

> I can see the theoretical advantages to this approach, but I would be
> lying if I said I used to religiously (I still don't keep that far
> ahead of the aircraft).

I suppose it depends to some extent on how much time you have on your hands.
If you're going to be in cruise for a long while, it's more practical than if
you know you're going to have to change altitude regularly (as over terrain of
widely varying elevations at lower altitudes).

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[Mxsmanic]

Paul kgyy writes:

> For serious climbing, use power and rich mixture, then reduce MP,
> prop, and mixture as needed at desired altitude.

_Always_ rich for a climb? At altitudes above a few thousand feet MSL, it
seems that a rich mixture just slows me down.

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[Maxwell]

"Mxsmanic" > wrote in message
...
> Paul kgyy writes:
>
>> For serious climbing, use power and rich mixture, then reduce MP,
>> prop, and mixture as needed at desired altitude.
>
> _Always_ rich for a climb? At altitudes above a few thousand feet MSL, it
> seems that a rich mixture just slows me down.
>

When was the last time you cleaned the plugs in your DESK?

[[email protected]]

In rec.aviation.piloting Mxsmanic > wrote:
> EridanMan writes:

> > It sounds like you're trying to fight the simulated phugoid
> > oscillation by using trim to make very low amplitude adjustments...

> I try it sometimes, on the theory that the more precise changes possible with
> tiny bits of trim might prevent me from overcorrecting, whereas gross movement
> of the yoke seems more likely to take me past the correct adjustment.

Pilots in real airplanes learn to fly using the yoke to control the
airplane and the trim to remove yoke pressure.

Since simulators that simulate yoke pressure cost as much as real
airplanes, you will never be able to do it.

> > This just increases the period of the oscillations, it in no way
> > prevents them from occurring.

> If the period becomes long enough, the oscillation is gone for all effective
> purposes.

> Sometimes I cheat and turn on the autopilot to trim out the oscillations. I
> also sometimes use the autopilot to trim and then adjust power until the AP is
> giving me neutral trim (which gives me more trim authority and hopefully
> reduces drag, although it also means that I can't necessarily fly at high
> speeds).

> > Power is a good, 'side effect free' mechanism of doing fine trimming
> > of your aircraft's altitude. In fact, I know instructors who advocate
> > only ever using the power to make the final 'lock' onto a new cruise
> > altitude, no matter what.

> See above. I've also tried setting neutral trim (in steps or in one
> adjustment) and then using power to find a setting that will keep me at the
> desired altitude with that trim. It seems to be more difficult but the
> aircraft is very stable once in that configuration.

In real aircraft you set the power to an appropriate value, adjust the
attitude for level flight, and trim off the pressure.

> > 500 feet below target altitude, push the nose forward gently to bring
> > airspeed up to cruise airspeed. Once you've reached cruise airspeed,
> > go ahead and trim to hold the attitude, but allow your power surplus
> > to continue pulling you up the last hundred feet or so to your target
> > altitude, only backing off the power the moment you reach it.

> That sounds like a plan. I don't know if I've tried it (I may have done so
> unconsciously, but I'll have to try it explicitly).

> > I can see the theoretical advantages to this approach, but I would be
> > lying if I said I used to religiously (I still don't keep that far
> > ahead of the aircraft).

> I suppose it depends to some extent on how much time you have on your hands.
> If you're going to be in cruise for a long while, it's more practical than if
> you know you're going to have to change altitude regularly (as over terrain of
> widely varying elevations at lower altitudes).

In a real airplane that burns real gas that costs real money, you climb
to a cruise altitude that allows for all the terrain and stay there.

--
Jim Pennino

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[[email protected]]

In rec.aviation.piloting Mxsmanic > wrote:
> Paul kgyy writes:

> > For serious climbing, use power and rich mixture, then reduce MP,
> > prop, and mixture as needed at desired altitude.

> _Always_ rich for a climb? At altitudes above a few thousand feet MSL, it
> seems that a rich mixture just slows me down.

In a real airplane with a real engine that generates real heat and
costs real money to overhaul there are conciderations beyond how
fast you go.

--
Jim Pennino

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[EridanMan]

> In a real airplane that burns real gas that costs real money, you climb
> to a cruise altitude that allows for all the terrain and stay there.

Hell, I dunno, I think in a real plane that burns real gas, his
inadvertent decision to toddle along at Vy would actually give him
pretty good gas milage;)

But yeah, I missed that bit.

[Mxsmanic]

writes:

> Pilots in real airplanes learn to fly using the yoke to control the
> airplane and the trim to remove yoke pressure.

That is only one of several ways to trim.

> Since simulators that simulate yoke pressure cost as much as real
> airplanes, you will never be able to do it.

See above. It's important to be flexible.

> In a real airplane that burns real gas that costs real money, you climb
> to a cruise altitude that allows for all the terrain and stay there.

That does not seem to be the consensus here.

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[Mxsmanic]

writes:

> In a real airplane with a real engine that generates real heat and
> costs real money to overhaul there are conciderations beyond how
> fast you go.

I guess that's a problem for real pilots. It's not a problem for me.

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[Bertie the Bunyip[_2_]]

Mxsmanic > wrote in
:

> writes:
>
>> In a real airplane with a real engine that generates real heat and
>> costs real money to overhaul there are conciderations beyond how
>> fast you go.
>
> I guess that's a problem for real pilots. It's not a problem for me.
>

you're not even an unreal, pilot, djikkhedd.


Bertie

[Paul kgyy]

>
> _Always_ rich for a climb? At altitudes above a few thousand feet MSL, it
> seems that a rich mixture just slows me down.
>
When you're climbing, airspeed is less and engine power is higher,
generating more heat in the air cooled cylinders. A rich mixture
helps keep cylinder temps under control because more fuel is
evaporated than is burned. Nothing is automatic with these old
engines, though Teledyne has developed a single lever Fadec system
that supposedly takes care of this with electronic monitoring. Still,
even Fadec should enrich the mixture in climb. Pilots with engine
monitors (JPI, EI) may not go to full rich when climbing since they
can monitor cylinder temps in real time.

If you want a good education on piston engine management, read through
John Deakin's articles in Avweb.

[[email protected]]

In rec.aviation.piloting Mxsmanic > wrote:
> writes:

> > Pilots in real airplanes learn to fly using the yoke to control the
> > airplane and the trim to remove yoke pressure.

> That is only one of several ways to trim.

In real airplanes making "gross" maneuvers, that is the way you trim.

For example, if you transition from climb to cruise, you use the yoke
to lower the nose, establish and maintain the altitude, stabilize the
airspeed, make any power adjustments, and once everything is stable,
trim off the yoke pressure. You may be making some trim adjustments
in the middle of it all to trim off pressure, but you are always
trimming off pressure.

In a stabilized mode, you may make minor trim adjustments if required.

> > Since simulators that simulate yoke pressure cost as much as real
> > airplanes, you will never be able to do it.

> See above. It's important to be flexible.

See above; it is how real airplanes are flown.

> > In a real airplane that burns real gas that costs real money, you climb
> > to a cruise altitude that allows for all the terrain and stay there.

> That does not seem to be the consensus here.

What makes you think that?

Unless you are in an ultralight chasing jackrabbits over sand dunes,
or something like pipe line patrol, you climb to a cruise altitude
and stay there in VFR flight.

--
Jim Pennino

Remove .spam.sux to reply.

[[email protected]]

In rec.aviation.piloting Mxsmanic > wrote:
> writes:

> > In a real airplane with a real engine that generates real heat and
> > costs real money to overhaul there are conciderations beyond how
> > fast you go.

> I guess that's a problem for real pilots. It's not a problem for me.

Then why bother asking how real airplanes fly?

Just go play with your simulator and do what you want.

Flying a real airplane requires concidering a pile of factors such
as aircraft performance, equipment and condition, weather, temperature,
density altitude, center of gravity, airspace types, pilot health and
general disposition, maneuvering speed, fuel burn, costs, engine
health, etc.


--
Jim Pennino

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[B A R R Y[_2_]]

Paul kgyy wrote:
> Nothing is automatic with these old
> engines,

Many carbs actually go beyond the mixture lever's full rich at wide open
throttle.

[Mxsmanic]

writes:

> In real airplanes making "gross" maneuvers, that is the way you trim.

In many; not in all.

> See above; it is how real airplanes are flown.

Some airplanes, not all.

> What makes you think that?

Because I'm getting lots of different answers. Obviously not everyone has the
same opinion.

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[Mxsmanic]

writes:

> Then why bother asking how real airplanes fly?

I know how real airplanes fly. The question in this case was which methods
pilots prefer for changes in altitude, since there are several ways to change
altitude.

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[Mxsmanic]

Paul kgyy writes:

> When you're climbing, airspeed is less and engine power is higher,
> generating more heat in the air cooled cylinders. A rich mixture
> helps keep cylinder temps under control because more fuel is
> evaporated than is burned.

But if you are, say, at 9000 or 10000 feet, don't you risk losing a lot of
power just when you need it most if you set a rich mixture?

The POH for the Baron I fly in the sim says "full rich or as required for
altitude," IIRC. Unfortunately it's not very specific about exactly how to
determine the correct mixture at higher altitudes.

> If you want a good education on piston engine management, read through
> John Deakin's articles in Avweb.

I think I have; I recall it being quite good, albeit complicated.

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[EridanMan]

> I try it sometimes, on the theory that the more precise changes possible with
> tiny bits of trim might prevent me from overcorrecting, whereas gross movement
> of the yoke seems more likely to take me past the correct adjustment.

I'm guessing this is a simulation artifact... The level of precision
control offered by the yoke is equal to that of trim in most
aircraft... But barring that, I can see how you might need to use a
simulated trim mechanism to 'fill in' and provide that precision.

> If the period becomes long enough, the oscillation is gone for all effective
> purposes.

Can I take back what I said? the period of the oscillations is totally
airframe dependent. Like any damped function, however, the
oscillations, even at low amplitude, can and will persist for a
surprisingly long time unless pro-damping actions are taken by the
pilot. Again, these are fairly minute, subconscious control inputs
that depend highly on precision - so there might be an input
constraint with your simulator.

> Sometimes I cheat and turn on the autopilot to trim out the oscillations.

Yes, this is cheating... but again probably a simulation work-around.

> I also sometimes use the autopilot to trim and then adjust power until the AP is
> giving me neutral trim (which gives me more trim authority and hopefully
> reduces drag, although it also means that I can't necessarily fly at high
> speeds).

Wow... that's actually kinda funny... You must get great simulated gas
mileage;)

'Neutral trim' is a false concept (an would be akin to saying that
there is a 'neutral airspeed' or more correctly 'neutral AOA'. The
only pre-defined Trim location on any aircraft is takeoff trim, which
is usually somewhere around Vy (not exactly because of variations in
atmospheric conditions and takeoff weight). The SOLE purpose of
takeoff trim is to make sure the pilot feels relatively consistent
forces on rotation/climbout.

What you are saying then is that you're getting to cruise altitude,
and then backing off until your flying near Vy airspeed... definitely
an efficient way of doing things, but generally not preferred by those
of us who lack time compression;)

There is no drag penalty for flying with forward trim, in general, the
aircraft will fly with forward trim whenever you are flying faster
than Vy, and back trim (nose up trip) whenever the aircraft is slower
than Vy, or 'behind the power curve'. In reality, you simply set the
aircraft up with your yoke for whatever configuration you want, trim
off the yoke pressure, and never pay attention to the actual.

> See above. I've also tried setting neutral trim (in steps or in one
> adjustment) and then using power to find a setting that will keep me at the
> desired altitude with that trim. It seems to be more difficult but the
> aircraft is very stable once in that configuration.

Again with the neutral trim... get away from that mindset.

As for holding an altitude... Its a rate-based control, so control
actions need to be very precise, but its really not that hard once you
get used to it - I suggest this would be a very good practice. I
would go ahead and try it at a range of speeds from Vy on up.

Again, the advantage is that you have a wide leeway to control the
aircraft's altitude while not inducing any harmonic instabilities...

> That sounds like a plan. I don't know if I've tried it (I may have done so
> unconsciously, but I'll have to try it explicitly).

Its fun to practice, I just don't remember enough when I'm up there.

Refined to perfection, the general idea is that you arrive at cruise
speed between 0-50 feet below target altitude, so that its all one
fluid motion.

I've ridden with several experience pilots who make this practice
second nature, and it really is the smoothest transition to level
flight I've ever experienced. Beats the hell out of my previous
practice of pushing the yoke forward to arrest ascent, letting the
ship accellerate, then fiddling for a minute to get everything in
order.

> I suppose it depends to some extent on how much time you have on your hands.

The goal would be to make it second nature such that it doesn't
distract you from your other cockpit duties.

> If you're going to be in cruise for a long while, it's more practical than if
> you know you're going to have to change altitude regularly

Again, the goal is to make it so that every time you transition from
climb/descending flight to cruise, you trim out and stabilize on
altitude automatically as a matter of second nature...

> (as over terrain of widely varying elevations at lower altitudes).

If you're changing your cruise altitude to account for variations in
elevation, you're not flight planning very well.

[[email protected]]

In rec.aviation.piloting Mxsmanic > wrote:
> writes:

> > In real airplanes making "gross" maneuvers, that is the way you trim.

> In many; not in all.

Yeah, I am sure a SR-71 is flown quite differently than a Cessna
152/172/182 or Piper Warrior/Archer, but you asked a general question
and I gave you a general answer for the majority of GA.

> > See above; it is how real airplanes are flown.

> Some airplanes, not all.

See above.

> > What makes you think that?

> Because I'm getting lots of different answers. Obviously not everyone has the
> same opinion.

No, you aren't, you just don't understand the answers because you have
no context.


--
Jim Pennino

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[[email protected]]

In rec.aviation.piloting Mxsmanic > wrote:
> writes:

> > Then why bother asking how real airplanes fly?

> I know how real airplanes fly. The question in this case was which methods
> pilots prefer for changes in altitude, since there are several ways to change
> altitude.

Once again you have no context to understand an answer.

How pilots of real airplanes change altitude has very little to do
with what a pilot prefers and a whole lot to do with the POH for
the airplane and general conciderations for the realities of airplanes
and engines.

--
Jim Pennino

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[[email protected]]

In rec.aviation.piloting Mxsmanic > wrote:
> Paul kgyy writes:

> > When you're climbing, airspeed is less and engine power is higher,
> > generating more heat in the air cooled cylinders. A rich mixture
> > helps keep cylinder temps under control because more fuel is
> > evaporated than is burned.

> But if you are, say, at 9000 or 10000 feet, don't you risk losing a lot of
> power just when you need it most if you set a rich mixture?

> The POH for the Baron I fly in the sim says "full rich or as required for
> altitude," IIRC. Unfortunately it's not very specific about exactly how to
> determine the correct mixture at higher altitudes.

That's because it is one of the things all real pilots have to learn
early in their training to fly real airplanes.

Real pilots are also trained to know that "as required for altitude"
means density altitude performance.

> > If you want a good education on piston engine management, read through
> > John Deakin's articles in Avweb.

> I think I have; I recall it being quite good, albeit complicated.

And yet another difference between simulated by Microsoft and real
flying...

--
Jim Pennino

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[Mxsmanic]

EridanMan writes:

> I'm guessing this is a simulation artifact... The level of precision
> control offered by the yoke is equal to that of trim in most
> aircraft... But barring that, I can see how you might need to use a
> simulated trim mechanism to 'fill in' and provide that precision.

The simulation of the actual effects of control and trim movements is most
likely completely accurate, but obviously there is no control pressure to
assist in setting trim. Essentially you have to trim and watch the reaction.
It's true that the controls are spring-loaded, and as you approach proper trim
you need push them less and less from their neutral position, but that's not
quite the same as control pressure (although it does closely approximate the
way it is done on a few aircraft).

> Can I take back what I said? the period of the oscillations is totally
> airframe dependent. Like any damped function, however, the
> oscillations, even at low amplitude, can and will persist for a
> surprisingly long time unless pro-damping actions are taken by the
> pilot. Again, these are fairly minute, subconscious control inputs
> that depend highly on precision - so there might be an input
> constraint with your simulator.

The precision of the sim is in the thousandths of a degree for trim (on
AP--hand adjustment is unfortunately much more coarse). I do occasionally see
the AP dealing with phugoid oscillations as well, but it handles them much
better than I do.

One thing I noticed that I found interesting was that at high power and low
altitude, when the AP is holding altitude and has a lot of nose-down trim
applied, I can see small, fairly rapid phugoid oscillations that the AP seems
to be battling with. I suppose the high power and low altitude conspire to
magnify this type of oscillation, so much so that the AP has a hard time ever
damping it out completely. This was not in the Baron, it was in the 747-400
at about 2000 feet and 355 KIAS (just below redline). The autothrottle was
engaged and that probably played a part, too. I don't know how much was the
fault of the autothrottle and how much was the fault of the airframe.

> Yes, this is cheating... but again probably a simulation work-around.

I'm sure it works in real life, too, but I don't know how many real pilots use
it.

> 'Neutral trim' is a false concept (an would be akin to saying that
> there is a 'neutral airspeed' or more correctly 'neutral AOA'.

Neutral--or zero--trim, on an aircraft that uses discrete trim tabs, is the
trim position in which the tabs are flush with the control surface that they
are designed to move. In this position, the control surface behaves exactly
as it would if there were no trim tabs at all. Thus, trim is neutral, or
zero.

In aircraft that move the entire stabilizer for trim adjustments, there isn't
any uniquely neutral position, although the manufacturer might still choose to
define one.

> The only pre-defined Trim location on any aircraft is takeoff trim, which
> is usually somewhere around Vy (not exactly because of variations in
> atmospheric conditions and takeoff weight). The SOLE purpose of
> takeoff trim is to make sure the pilot feels relatively consistent
> forces on rotation/climbout.

I have noted that a smooth rotation seems easier with trim applied per the
manufacturer's recommendation. If I take off with zero trim the aircraft
seems to want to abruptly jump off the runway.

> What you are saying then is that you're getting to cruise altitude,
> and then backing off until your flying near Vy airspeed... definitely
> an efficient way of doing things, but generally not preferred by those
> of us who lack time compression;)

Surprisingly, I haven't noticed that much of a decrease in speed, but it
depends a lot on altitude. At higher altitudes the impact on speed is small,
at lower altitudes you have to back off the throttle so much to get neutral
trim that you slow down noticeably.

> There is no drag penalty for flying with forward trim, in general, the
> aircraft will fly with forward trim whenever you are flying faster
> than Vy, and back trim (nose up trip) whenever the aircraft is slower
> than Vy, or 'behind the power curve'.

I suppose the nose-down trim is actually setting the AOA to nearly zero
degrees, so perhaps it imparts the least drag (?).

> In reality, you simply set the
> aircraft up with your yoke for whatever configuration you want, trim
> off the yoke pressure, and never pay attention to the actual.

Seems a bit risky, but I suppose it works well enough.

> Again with the neutral trim... get away from that mindset.

Why? If it has trim tabs, it has a neutral trim position. And presumably if
it has neutral trim, the control surface is roughly midway between its
extremes of movement, which gives maximum control authority in both
directions.

> As for holding an altitude... Its a rate-based control, so control
> actions need to be very precise, but its really not that hard once you
> get used to it - I suggest this would be a very good practice. I
> would go ahead and try it at a range of speeds from Vy on up.

I still need to practice hand-trimming the aircraft a lot more.

> Again, the goal is to make it so that every time you transition from
> climb/descending flight to cruise, you trim out and stabilize on
> altitude automatically as a matter of second nature...

I see the advantage for long periods with a given attitude to maintain, but
what would be the advantage if you know you're going to be changing the
aircraft attitude again within a few seconds or minutes?

> If you're changing your cruise altitude to account for variations in
> elevation, you're not flight planning very well.

If almost all the terrain along my route is at 1500 feet MSL except for one
small mountain range that extends up to 9000 feet, I'm not sure that I want to
fly the entire route at 11500 feet just because I'll need to clear that one
mountain. This is especially true since I'm going to need oxygen at higher
altitudes.

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[EridanMan]

> The simulation of the actual effects of control and trim movements is most
> likely completely accurate, but obviously there is no control pressure to
> assist in setting trim. Essentially you have to trim and watch the reaction.

Yeah, this is a fairly major input constraint in my mind - in a real
aircraft, you know you are in correct trim very quickly and easily
based simply on the amount of force your applying to the yoke.

FWIW, Trim was the single largest aspect of aircraft piloting that my
simulation experience simply did not prepare me for... I mean, the
concept is there, but how often you need it and why simply never came
across clearly.

> It's true that the controls are spring-loaded, and as you approach proper trim
> you need push them less and less from their neutral position, but that's not
> quite the same as control pressure (although it does closely approximate the
> way it is done on a few aircraft).

I've never experienced a simulated aircraft control that didn't have a
substantial dead spot in the middle and feel extremely artificial.

Also, I'm reasonably sure that yoke forces are exponential, rather
than linear, and that this plays a large roll in the 'feel issue'...
Something to consider.

> The precision of the sim is in the thousandths of a degree for trim (on
> AP--hand adjustment is unfortunately much more coarse).

In an aircraft, yoke adjustments are based on pressure applied to the
yoke... if the aircraft is properly trimmed out, even VERY fine
pressures will affect the aircraft's attitude.

I think this actually a good lay-mans definition of the fundamental
point of trim... It is very difficult for a human to judge the
difference between 5lbs and 5 lbs 1 oz of force, it is very easy for
us to judge the difference between 0 pressure and 1 oz (simply
physiology). By allowing the pilot to trim off excessive, constant
yoke pressure, the pilot is then able to judge and apply very fine
correctional forces on the yoke.

> I do occasionally see the AP dealing with phugoid oscillations as well, but it handles them much
> better than I do.

I wouldn't fret about that... the main mechanism the pilot's use to
handle phugoid oscillations isn't available to you (yoke pressure), so
your operating at an understandable disadvantage there.

> One thing I noticed that I found interesting was that at high power and low
> altitude, when the AP is holding altitude and has a lot of nose-down trim
> applied, I can see small, fairly rapid phugoid oscillations that the AP seems
> to be battling with.

My guess is that this actually has more to do with the FS 747 model
loosing accuracy at the limit's of the aircraft's envelope. The
models are abstractions of aircraft performance, and as such, while
they do a good job, there are necessary compromises that must be
made. I would imagine most simulation makers would choose to optimize
the model to provide the most realistic behavior for the portions of
the aircraft envelope that sim pilots will spend most of their time
in, but this will come at a cost of poorer simulation of the extremes.

> I suppose the high power and low altitude conspire to
> magnify this type of oscillation, so much so that the AP has a hard time ever
> damping it out completely. This was not in the Baron, it was in the 747-400
> at about 2000 feet and 355 KIAS (just below redline). The autothrottle was
> engaged and that probably played a part, too. I don't know how much was the
> fault of the autothrottle and how much was the fault of the airframe.

I think you're probably thinking too much into this. Not being a 747
pilot, I can't say for sure (nor do I think that would matter, as 355
KIAS below 10K ft would very quickly loose a pilot his ticket). But
understand that you are not only dealing with the engineering
limitations of the aircraft, but also the engineering limitations of
the simulation model...

> I'm sure it works in real life, too, but I don't know how many real pilots use
> it.

Raises an interesting question as to how AP's deal with phugoid
oscillations, I have no idea.

In practice, with a hand on a yoke though, I can't see why a pilot
would ever bother.

> Neutral--or zero--trim, on an aircraft that uses discrete trim tabs, is the
> trim position in which the tabs are flush with the control surface that they
> are designed to move. In this position, the control surface behaves exactly
> as it would if there were no trim tabs at all. Thus, trim is neutral, or
> zero.

Ok, I see what your saying, but its still utterly irrelevant.

Trim exists for one reason - to allow the aircraft to fly with no yoke
pressure throughout its AOA envelope.

Drag effects from the trim tab are consequences of the engineering
decision to use a discreet trim tab for the aircraft, and as such, are
the domain of the aircraft designers who engineered the system. My
suspicion is that neutral trim is drag optimized again for Vy flight,
where it will have the most 'utility' in terms of greater climb rates,
but I can't say that for certain.

> In aircraft that move the entire stabilizer for trim adjustments, there isn't
> any uniquely neutral position, although the manufacturer might still choose to
> define one.

Such as my Piper.

I'll say it again though - there is no more 'neutral trim' than there
is a 'neutral AOA' as far as the pilot is concerned, by simple,
fundamental definition. The mechanisms behind the trim are not our
concern, what matters to us is that the aircraft provides a mechanism
to remove yoke pressure throughout the aircraft's operating range.
Period.

> I have noted that a smooth rotation seems easier with trim applied per the
> manufacturer's recommendation. If I take off with zero trim the aircraft
> seems to want to abruptly jump off the runway.

This actually suggests to me that the 'neutral trim' position your
aircraft provides is actually a bit behind Vy (closer to Vx?)

> Surprisingly, I haven't noticed that much of a decrease in speed, but it
> depends a lot on altitude. At higher altitudes the impact on speed is small,
> at lower altitudes you have to back off the throttle so much to get neutral
> trim that you slow down noticeably.

At higher altitudes, you spend more time near your indicated Vy
airspeed anyways (even though your TAS is usually higher), so this
makes sense.

> I suppose the nose-down trim is actually setting the AOA to nearly zero
> degrees, so perhaps it imparts the least drag (?).

Lowest Induced drag at the least... Flying at the airspeed required to
attain sufficient lift to maintain altitude at this airspeed will of
course replace that Induced drag with even more profile drag... part
of the compromise of aircraft design.

> Seems a bit risky, but I suppose it works well enough.

This is one of those, 'do it once and you'll understand' deals... its
really not that hard.

> Why? If it has trim tabs, it has a neutral trim position. And presumably if
> it has neutral trim, the control surface is roughly midway between its
> extremes of movement, which gives maximum control authority in both
> directions.

That's like saying you should always fly in the middle of the
aircrafts airspeed envelope because it gives you the most options to
speed up or slow down... its somewhat irrelevant to the point of
having an aircraft that can operate in a wide envelope.

If the aircraft is well designed, you should have full control
authority at any trimmed AOA.

> I still need to practice hand-trimming the aircraft a lot more.

Without the necessary tactile inputs, this may be somewhat futile.

> I see the advantage for long periods with a given attitude to maintain, but
> what would be the advantage if you know you're going to be changing the
> aircraft attitude again within a few seconds or minutes?

Once it becomes second nature, it doesn't matter how long you'll be at
a particular altitude... set it up in the first five seconds and be
done with it.

Your only other option is to distract yourself making corrections
every 30 seconds until you move on to another flight level... Might as
well learn to do it right every time and not worry about it.

> If almost all the terrain along my route is at 1500 feet MSL except for one
> small mountain range that extends up to 9000 feet, I'm not sure that I want to
> fly the entire route at 11500 feet just because I'll need to clear that one
> mountain. This is especially true since I'm going to need oxygen at higher
> altitudes.

You made it sound like you were spending just a few minutes at each
altitude... Yes, I'll have legs where I climb and descend, but
understand that on a typical cross country flight, your way points are
20-40 minutes apart... so of course your going to stabilize on each
leg.

[[email protected]]

In rec.aviation.piloting EridanMan > wrote:
> I think I get the credit for confusing MX here, as the procedure I
> listed differs from yours.

> What you describe is what I 'normally' do - arrest the altitude change
> with the yoke, accelerate to Vy in straight and level flight, then
> trim out and use power to 'tweak' my altitude.

> Flying with _much_ more experienced pilots, I've seen (and been told)
> that the procedure I mentioned (accelerating to Vy while in the last
> stage of the ascent, trim off pressure, then allow your power surplus
> to pull you up the past few feet to altitude and stop precisely at it)
> leads to a smoother, more 'natural' process- you get in the habit of
> _always_ controlling your specific altitude precisely with the
> throttle, and you end up in a pure, stabilized, oscillation free
> cruise.

> Downsides are that the engine stays at climb power for longer
> (although I'd argue this is negligible), and in order to execute the
> maneuver properly, you need to be enough ahead of the aircraft
> initiate it early enough.

> I'll be the first to admit I'm a sub 100 hour pilot with lots of
> second hand knowledge but a shortage of in-cockpit experience, so if
> disagree with this procedure, PLEASE, by all means let me know why;)

Well, since all airplanes are a little different, one can expect
differences in the fine points of technique.

Until I bought my Tiger, most of my time was in 172's and they are
different in how they react when you level off for cruise from a
climb. The difference in airspeed between climb and cruise is
bigger than in the 172 as is the throttle setting and takes a little
longer to stabilize.

The technique I've found that is the smoothest in the Tiger is at
about 50 feet short of altitude to start bringing the nose down
to a centered position of the AI while keeping one eye on the
altitude. Once at altitude, use increasing pressure on the yoke
to keep the altitude constant and trim off pressure as it gets
higher. I don't change the throttle setting until it starts to
get close to red line and then back it off to the desired cruise
RPM. After a while things stabilize and I tweek the throttle again
to the desired cruise RPM, wait a bit and tweek off all the remaining
pressure and sit back.

I did have to do a bunch of practice transitions to get it down
to a smooth procedure.

As to why look at the AI, the view in the Tiger is so different
that if you are used to the view in a 172, you will swear you
are in a dive when you are actually level.

For me, in a 172 the nose when level is just below the horizon and
it's easy to see if I'm level. In the Tiger, the nose is WAY below
the horizon when level.

When I first tried to fly the Tiger the same way I flew the 172
my altitude was all over the place and I was constantly fiddling
with one thing or the other.

You milage may vary.

--
Jim Pennino

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[[email protected]]

In rec.aviation.piloting Gary > wrote:
> On Apr 12, 2:52 pm, Mxsmanic > wrote:
> > The simulation of the actual effects of control and trim movements is most
> > likely completely accurate, but obviously there is no control pressure to
> > assist in setting trim. Essentially you have to trim and watch the reaction.

> What you have stated here is that the control and trim simulation is
> NOT completely accurate. Without control pressure, it's not even
> close.

In the early development of fly-by-wire systems it was discovered that
most, if not all, pilots can not precisely control an airplane without
the feedback provided by yoke pressure.

Typically, they would get behind the airplane.

--
Jim Pennino

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[Mxsmanic]

Gary writes:

> What you have stated here is that the control and trim simulation is
> NOT completely accurate. Without control pressure, it's not even
> close.

The only thing missing is the control pressure.

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[Mxsmanic]

EridanMan writes:

> FWIW, Trim was the single largest aspect of aircraft piloting that my
> simulation experience simply did not prepare me for... I mean, the
> concept is there, but how often you need it and why simply never came
> across clearly.

I suppose so ... but how long did it take you to learn to adjust trim by
relieving pressure on the yoke? Thirty seconds? Three minutes?

> I've never experienced a simulated aircraft control that didn't have a
> substantial dead spot in the middle and feel extremely artificial.

Well, you have to look at it a different way. On a (PC) sim, the "dead spot"
actually corresponds to "zero control pressure," or at least that's how it
usually seems to work (I think it depends on how the aircraft is modeled, but
good add-ons work this way). In other words, you can trim by holding the yoke
or joystick away from its neutral position and then trimming until you can
leave the joystick in the neutral position. This is very similar to relieving
control pressure. The joystick of the sim does not use absolute positioning.

> Also, I'm reasonably sure that yoke forces are exponential, rather
> than linear, and that this plays a large roll in the 'feel issue'...
> Something to consider.

I don't know. It would be interesting to see the curves of spring resistance
plotted against the forces exerted on the yoke when out of trim.

> I wouldn't fret about that... the main mechanism the pilot's use to
> handle phugoid oscillations isn't available to you (yoke pressure), so
> your operating at an understandable disadvantage there.

Better for it to be harder than easier. It means that flying the real thing
would be easy compared to flying the sim.

> My guess is that this actually has more to do with the FS 747 model
> loosing accuracy at the limit's of the aircraft's envelope.

I'm not so sure. The 747-400 has a custom-written model that is independent
of MSFS. They supposedly spent years working on it. But nobody flies 747s at
2000 feet and 355 knots in real life (I think), so it doesn't matter that
much. The oscillation was very small, but you can "feel" that the aircraft is
oscillating a bit in watching the instruments.

> I would imagine most simulation makers would choose to optimize
> the model to provide the most realistic behavior for the portions of
> the aircraft envelope that sim pilots will spend most of their time
> in, but this will come at a cost of poorer simulation of the extremes.

But is low altitude and high speed really an extreme, or just different?

> Raises an interesting question as to how AP's deal with phugoid
> oscillations, I have no idea.

I presume they work predictively, by calculation how much correction to apply
ahead of the aircraft. Pilots can't do this as well.

It's like having a weight swinging on a chain: If you try to compensate for
the swinging reactively, it takes forever to get it to stop. But if you
anticipate the movement of the weight and compensate for it as it happens, you
can get the weight to stop swinging entirely in one or two swings.

> I'll say it again though - there is no more 'neutral trim' than there
> is a 'neutral AOA' as far as the pilot is concerned, by simple,
> fundamental definition. The mechanisms behind the trim are not our
> concern, what matters to us is that the aircraft provides a mechanism
> to remove yoke pressure throughout the aircraft's operating range.
> Period.

I can't agree. If you pull the yoke way back and then trim to eliminate yoke
pressure, you're not at all in the same state you'd be in if you had the yoke
pretty much in a middle position and then trimmed to that. In the former
case, you're close to the end of travel for the control surface; in the latter
case, you have plenty of margin for movement in both directions.

If you've trimmed for a lot of nose-up pitch and you suddenly decide you need
more, you may find that none is left. If you trim for a more neutral pitch,
there's plenty there when you need it. Trimming for extreme pitch attitudes
could lull you into thinking that you are further from the extremes of pitch
than you actually are.

This is why I'm hesitant to trim for extreme pitch attitudes. I want to be
reminded that the pitch is still fairly extreme. If I just trim the yoke
pressure away, I might forget.

> This actually suggests to me that the 'neutral trim' position your
> aircraft provides is actually a bit behind Vy (closer to Vx?)

I don't know. What I do know is that zero on the trim indicator corresponds
to neutral trim in that the trim tabs are flush with the elevator.

> That's like saying you should always fly in the middle of the
> aircrafts airspeed envelope because it gives you the most options to
> speed up or slow down... its somewhat irrelevant to the point of
> having an aircraft that can operate in a wide envelope.
>
> If the aircraft is well designed, you should have full control
> authority at any trimmed AOA.

That isn't possible if you are using trim tabs; it's possible if the entire
stabilizer moves. If you have tabs, the tabs move the control surface, but
the range of movement of that surface does not change. So if you trim such
that the surface moves towards one of its extremes, the remaining authority at
that extreme is reduced.

I suppose that in small aircraft the position of the yoke after trimming gives
you a visual indication of the actual position of the control surfaces. My
concern, though, is that you might apply a lot of trim and then forget that
you have done so, and when you then try to push or pull the yoke you find that
you've already trimmed out most of the movement of the control surface,
leaving you with very little margin. But perhaps if you can see the yoke
move, this is less of a problem.

> Without the necessary tactile inputs, this may be somewhat futile.

Why? If it works on the sim, it willl work in real life, even though real
life may also offer a simpler method.

> You made it sound like you were spending just a few minutes at each
> altitude... Yes, I'll have legs where I climb and descend, but
> understand that on a typical cross country flight, your way points are
> 20-40 minutes apart... so of course your going to stabilize on each
> leg.

In my sim flights I go over the Rockies and their cousins a lot, and since
some of them are quite high, I don't like to stay at high altitudes all the
time with a virtual oxygen mask or canula. So I might try to fly at 7500, but
periodically I need to climb several thousand feet and/or make a detour when
high mountains loom. There are a few areas where this does involve changing
altitude a lot.

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[Mxsmanic]

writes:

> That's because it is one of the things all real pilots have to learn
> early in their training to fly real airplanes.

So, where do I set it in the Baron for, say, 9000 feet? You must have learned
how do determine this in your training to fly real airplanes, so you should be
able to tell me where to set the lever.

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[[email protected]]

In rec.aviation.piloting Mxsmanic > wrote:
> writes:

> > That's because it is one of the things all real pilots have to learn
> > early in their training to fly real airplanes.

> So, where do I set it in the Baron for, say, 9000 feet? You must have learned
> how do determine this in your training to fly real airplanes, so you should be
> able to tell me where to set the lever.

In lieu of any instrumentation or a POH with a procedure, lean slowly
until maximum RPM and back off a couple of turns.


--
Jim Pennino

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[Mxsmanic]

writes:

> In lieu of any instrumentation or a POH with a procedure, lean slowly
> until maximum RPM and back off a couple of turns.

What's the maximum RPM, and how many turns is "a couple"? You said all real
pilots learn that, so they don't need to look anything up.

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[Maxwell]

"Mxsmanic" > wrote in message
...
> writes:
>
>> In lieu of any instrumentation or a POH with a procedure, lean slowly
>> until maximum RPM and back off a couple of turns.
>
> What's the maximum RPM, and how many turns is "a couple"? You said all
> real
> pilots learn that, so they don't need to look anything up.
>

It's all about control pressure and the sound of the engine.

Even in the sim, you trim to maintian your pitch attitude hands off, that's
all that it's there for, control pressure varys a lot in actual flight,
nothing like the sim. If you change speed, pitch or power setting and 90% of
the time you will have to retrim at least a little. So no matter what you
are doing, proper use of the trim just allows you to fly hands off.

Leaning is something most of us do by the sound of the engine unless we have
instruments to assist.

Both are easy to demonstrate in an actual flight, and would make a much
better topic for rec.aviation.student. To a certificated pilot even with the
least experience, it's much like saying teach me how to set the heater in my
car.

[Maxwell]

"Mxsmanic" > wrote in message
...
> Gary writes:
>
>> What you have stated here is that the control and trim simulation is
>> NOT completely accurate. Without control pressure, it's not even
>> close.
>
> The only thing missing is the control pressure.

Exactly. And trim is only used for eliminating control pressure.

[[email protected]]

In rec.aviation.piloting Mxsmanic > wrote:
> writes:

> > In lieu of any instrumentation or a POH with a procedure, lean slowly
> > until maximum RPM and back off a couple of turns.

> What's the maximum RPM, and how many turns is "a couple"? You said all real
> pilots learn that, so they don't need to look anything up.

maximum
adj.
1. Having or being the greatest quantity or the highest degree that
has been or can be attained: maximum temperature.
2. Of, relating to, or making up a maximum: a maximum number in a series.

couple
adj.
Two or few

If your engine has a propensity to run hot, you might want to back off
three turns.

--
Jim Pennino

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[Mxsmanic]

Maxwell writes:

> Exactly. And trim is only used for eliminating control pressure.

Trim is also used by many autopilots.

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[Mxsmanic]

writes:

> If your engine has a propensity to run hot, you might want to back off
> three turns.

The mixture lever does not turn.

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[Gig 601XL Builder]

Mxsmanic wrote:
> Maxwell writes:
>
>> Exactly. And trim is only used for eliminating control pressure.
>
> Trim is also used by many autopilots.

Trim is used by many autopilots to eliminate, say it with me.... control
pressure. That server doesn't want to fight an out of trim condition anymore
than a pilot does.

[Mxsmanic]

Gig 601XL Builder writes:

> Trim is used by many autopilots to eliminate, say it with me.... control
> pressure.

No, trim is used by many autopilots to maintain the selected altitude,
heading, or track. Autopilots don't care about control pressure.

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[[email protected]]

In rec.aviation.piloting Mxsmanic > wrote:
> writes:

> > If your engine has a propensity to run hot, you might want to back off
> > three turns.

> The mixture lever does not turn.

Then back off the appropriate number of notches.

--
Jim Pennino

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[Snowbird]

"Mxsmanic" wrote ..

>
> No, trim is used by many autopilots to maintain the selected altitude,
> heading, or track. Autopilots don't care about control pressure.
>

Please refrain from posting assertions you have no clue about.

Autopilots certainly want to trim out control pressure. Think about what
would otherwise happen when you disconnect the autopilot. Duh.

[Just go look it up!]

On Fri, 13 Apr 2007 22:39:47 +0300, "Snowbird"
> wrote:

>
>"Mxsmanic" wrote ..
>
>>
>> No, trim is used by many autopilots to maintain the selected altitude,
>> heading, or track. Autopilots don't care about control pressure.
>>
>
>Please refrain from posting assertions you have no clue about.
>
>Autopilots certainly want to trim out control pressure. Think about what
>would otherwise happen when you disconnect the autopilot. Duh.

Even more basically, if the servo didn't care about pressure then why
would it have a feedback generator to tell the trim servo just how
much adjustments it needs?

[Gig 601XL Builder]

Mxsmanic wrote:
> Gig 601XL Builder writes:
>
>> Trim is used by many autopilots to eliminate, say it with me....
>> control pressure.
>
> No, trim is used by many autopilots to maintain the selected altitude,
> heading, or track. Autopilots don't care about control pressure.

They don't because they don't have emotions. But the owners of the A/P do
care because if the A/P servo is having to fight the control pressure it is
also going to wear out sooner.

There is also the safety factor. If the A/P is flying the aircraft in an
untrimed state and then the A/P fails the aircraft is going to go into
either a dive or a climb.

P.S. My new policy is to attempt to answer Anthony once. With only a single
follow up only if he asks a question or states a position that a non-pilot
pilot might not know. I do this because he does ask some interesting
questions that others might read someday.

Hence, this is my last post on this subject.

[george]

On Apr 13, 9:41 am, "EridanMan" > wrote:
> > The simulation of the actual effects of control and trim movements is most
> > likely completely accurate, but obviously there is no control pressure to
> > assist in setting trim. Essentially you have to trim and watch the reaction.
>
> Yeah, this is a fairly major input constraint in my mind - in a real
> aircraft, you know you are in correct trim very quickly and easily
> based simply on the amount of force your applying to the yoke.
>
> FWIW, Trim was the single largest aspect of aircraft piloting that my
> simulation experience simply did not prepare me for... I mean, the
> concept is there, but how often you need it and why simply never came
> across clearly.
>
> > It's true that the controls are spring-loaded, and as you approach proper trim
> > you need push them less and less from their neutral position, but that's not
> > quite the same as control pressure (although it does closely approximate the
> > way it is done on a few aircraft).
>
> I've never experienced a simulated aircraft control that didn't have a
> substantial dead spot in the middle and feel extremely artificial.
>
> Also, I'm reasonably sure that yoke forces are exponential, rather
> than linear, and that this plays a large roll in the 'feel issue'...
> Something to consider.
>
> > The precision of the sim is in the thousandths of a degree for trim (on
> > AP--hand adjustment is unfortunately much more coarse).
>
> In an aircraft, yoke adjustments are based on pressure applied to the
> yoke... if the aircraft is properly trimmed out, even VERY fine
> pressures will affect the aircraft's attitude.
>
> I think this actually a good lay-mans definition of the fundamental
> point of trim... It is very difficult for a human to judge the
> difference between 5lbs and 5 lbs 1 oz of force, it is very easy for
> us to judge the difference between 0 pressure and 1 oz (simply
> physiology). By allowing the pilot to trim off excessive, constant
> yoke pressure, the pilot is then able to judge and apply very fine
> correctional forces on the yoke.
>
> > I do occasionally see the AP dealing with phugoid oscillations as well, but it handles them much
> > better than I do.
>
> I wouldn't fret about that... the main mechanism the pilot's use to
> handle phugoid oscillations isn't available to you (yoke pressure), so
> your operating at an understandable disadvantage there.
>
> > One thing I noticed that I found interesting was that at high power and low
> > altitude, when the AP is holding altitude and has a lot of nose-down trim
> > applied, I can see small, fairly rapid phugoid oscillations that the AP seems
> > to be battling with.
>
> My guess is that this actually has more to do with the FS 747 model
> loosing accuracy at the limit's of the aircraft's envelope. The
> models are abstractions of aircraft performance, and as such, while
> they do a good job, there are necessary compromises that must be
> made. I would imagine most simulation makers would choose to optimize
> the model to provide the most realistic behavior for the portions of
> the aircraft envelope that sim pilots will spend most of their time
> in, but this will come at a cost of poorer simulation of the extremes.
>
> > I suppose the high power and low altitude conspire to
> > magnify this type of oscillation, so much so that the AP has a hard time ever
> > damping it out completely. This was not in the Baron, it was in the 747-400
> > at about 2000 feet and 355 KIAS (just below redline). The autothrottle was
> > engaged and that probably played a part, too. I don't know how much was the
> > fault of the autothrottle and how much was the fault of the airframe.
>
> I think you're probably thinking too much into this. Not being a 747
> pilot, I can't say for sure (nor do I think that would matter, as 355
> KIAS below 10K ft would very quickly loose a pilot his ticket). But
> understand that you are not only dealing with the engineering
> limitations of the aircraft, but also the engineering limitations of
> the simulation model...
>
> > I'm sure it works in real life, too, but I don't know how many real pilots use
> > it.
>
> Raises an interesting question as to how AP's deal with phugoid
> oscillations, I have no idea.
>
> In practice, with a hand on a yoke though, I can't see why a pilot
> would ever bother.
>
> > Neutral--or zero--trim, on an aircraft that uses discrete trim tabs, is the
> > trim position in which the tabs are flush with the control surface that they
> > are designed to move. In this position, the control surface behaves exactly
> > as it would if there were no trim tabs at all. Thus, trim is neutral, or
> > zero.
>
> Ok, I see what your saying, but its still utterly irrelevant.
>
> Trim exists for one reason - to allow the aircraft to fly with no yoke
> pressure throughout its AOA envelope.
>
> Drag effects from the trim tab are consequences of the engineering
> decision to use a discreet trim tab for the aircraft, and as such, are
> the domain of the aircraft designers who engineered the system. My
> suspicion is that neutral trim is drag optimized again for Vy flight,
> where it will have the most 'utility' in terms of greater climb rates,
> but I can't say that for certain.
>
> > In aircraft that move the entire stabilizer for trim adjustments, there isn't
> > any uniquely neutral position, although the manufacturer might still choose to
> > define one.
>
> Such as my Piper.
>
> I'll say it again though - there is no more 'neutral trim' than there
> is a 'neutral AOA' as far as the pilot is concerned, by simple,
> fundamental definition. The mechanisms behind the trim are not our
> concern, what matters to us is that the aircraft provides a mechanism
> to remove yoke pressure throughout the aircraft's operating range.
> Period.
>
> > I have noted that a smooth rotation seems easier with trim applied per the
> > manufacturer's recommendation. If I take off with zero trim the aircraft
> > seems to want to abruptly jump off the runway.
>
> This actually suggests to me that the 'neutral trim' position your
> aircraft provides is actually a bit behind Vy (closer to Vx?)
>
> > Surprisingly, I haven't noticed that much of a decrease in speed, but it
> > depends a lot on altitude. At higher altitudes the impact on speed is small,
> > at lower altitudes you have to back off the throttle so much to get neutral
> > trim that you slow down noticeably.
>
> At higher altitudes, you spend more time near your indicated Vy
> airspeed anyways (even though your TAS is usually higher), so this
> makes sense.
>
> > I suppose the nose-down trim is actually setting the AOA to nearly zero
> > degrees, so perhaps it imparts the least drag (?).
>
> Lowest Induced drag at the least... Flying at the airspeed required to
> attain sufficient lift to maintain altitude at this airspeed will of
> course replace that Induced drag with even more profile drag... part
> of the compromise of aircraft design.
>
> > Seems a bit risky, but I suppose it works well enough.
>
> This is one of those, 'do it once and you'll understand' deals... its
> really not that hard.

Anything more force on the wheel than thumb and forefinger supply I
reach for the trim

[[email protected]]

On Apr 12, 8:01 pm, Mxsmanic > wrote:
> I can't agree. If you pull the yoke way back and then trim to eliminate yoke
> pressure, you're not at all in the same state you'd be in if you had the yoke
> pretty much in a middle position and then trimmed to that. In the former
> case, you're close to the end of travel for the control surface; in the latter
> case, you have plenty of margin for movement in both directions.
>
> If you've trimmed for a lot of nose-up pitch and you suddenly decide you need
> more, you may find that none is left. If you trim for a more neutral pitch,
> there's plenty there when you need it. Trimming for extreme pitch attitudes
> could lull you into thinking that you are further from the extremes of pitch
> than you actually are.
>
> This is why I'm hesitant to trim for extreme pitch attitudes. I want to be
> reminded that the pitch is still fairly extreme. If I just trim the yoke
> pressure away, I might forget.
>
> ....
>
> I suppose that in small aircraft the position of the yoke after trimming gives
> you a visual indication of the actual position of the control surfaces. My
> concern, though, is that you might apply a lot of trim and then forget that
> you have done so, and when you then try to push or pull the yoke you find that
> you've already trimmed out most of the movement of the control surface,
> leaving you with very little margin. But perhaps if you can see the yoke
> move, this is less of a problem.

You're demonstrating that you've never been in a real
plane, nor even in a good simulator ("good" meaning
one that simulates control pressure).

You don't trim for pitch. You trim to remove
control pressure at a given AoA, which is
fairly intimately tied to airspeed. It's an
oversimplification to say that the elevator is
your plane's speed control while the throttle is
your altitude control, but that oversimplification
is much closer to the truth than the other
oversimplification which says that the throttle
is your speed control and the elevator is your
altitude control.

Pick up a copy of Langewiesche's "Stick and
Rudder" for a good explanation of how all this
works. It's the classic text by the master.

Anyway, if you're trimmed for a very slow
airspeed, (high AoA, nose-up pitch) you'll
absolutely know it. You'll know it by the sloppy
feel of the controls, the sound the plane makes,
and your airspeed indicator. Likewise, if you're
trimmed for a very high airspeed, you'll know
it by the stiff controls, the sound, and the
airspeed indicator.

If your weight and balance is well outside
the operating envelope of the aircraft, you
might run out of elevator authority, but that
would happen regardless of how you handle
trimming.

[[email protected]]

On Apr 12, 7:25 pm, Mxsmanic > wrote:
> Gary writes:
> > What you have stated here is that the control and trim simulation is
> > NOT completely accurate. Without control pressure, it's not even
> > close.
>
> The only thing missing is the control pressure.

Missing control pressure is obviously enough to
give you very wrong ideas about how planes fly,
but note that it's not the only thing missing.
Your control displacement is not
simulated accurately, either.

Assuming you're in straight and level flight,
with constant power setting: when you change
trim, do you adjust the yoke (or joystick)
position to keep things straight and level?
I thought so. Do you see the problem?

[Mxsmanic]

Snowbird writes:

> Autopilots certainly want to trim out control pressure. Think about what
> would otherwise happen when you disconnect the autopilot. Duh.

It actually _does_ happen when you disconnect the autopilot, in some aircraft.
The purpose of the autopilot is not to relieve control pressure, it is to fly
the aircraft. In aircraft that use trim for the autopilot, the aircraft may
be stable when you turn the autopilot off. However, in aircraft that directly
manipulate the controls with the autopilot, the aircraft may suddenly change
attitude when the AP is shut off, if the AP has been compensating for
something (such as an engine failure) while it has been operating. This has
caused accidents.

--
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[Mxsmanic]

Just go look it up! writes:

> Even more basically, if the servo didn't care about pressure then why
> would it have a feedback generator to tell the trim servo just how
> much adjustments it needs?

Different autopilots work in different ways. The autopilot maintains altitude,
or heading; it does not relieve control pressure. If the aircraft is
perfectly trimmed at 5000 feet and you set the autopilot for 4000 feet, the
autopilot will adjust trim (in APs that work this way) despite the absence of
any control pressure. An autopilot looks at instrument readings, not control
pressures--some aircraft don't even have control pressures.

--
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[Mxsmanic]

Gig 601XL Builder writes:

> They don't because they don't have emotions. But the owners of the A/P do
> care because if the A/P servo is having to fight the control pressure it is
> also going to wear out sooner.

If the servo actuates the control column.

> There is also the safety factor. If the A/P is flying the aircraft in an
> untrimed state and then the A/P fails the aircraft is going to go into
> either a dive or a climb.

Yes, and sometimes that actually happens, with unfortunate results.

--
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[Mxsmanic]

writes:

> You're demonstrating that you've never been in a real
> plane, nor even in a good simulator ("good" meaning
> one that simulates control pressure).

Some people here have only been in one type of aircraft, and mistakenly
believe that all aircraft are the same.

> Anyway, if you're trimmed for a very slow
> airspeed, (high AoA, nose-up pitch) you'll
> absolutely know it. You'll know it by the sloppy
> feel of the controls, the sound the plane makes,
> and your airspeed indicator. Likewise, if you're
> trimmed for a very high airspeed, you'll know
> it by the stiff controls, the sound, and the
> airspeed indicator.

In some aircraft, yes. But I wouldn't trust that in all aircraft.

--
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[Mxsmanic]

writes:

> Then back off the appropriate number of notches.

How many notches?

--
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[Mxsmanic]

writes:

> Assuming you're in straight and level flight,
> with constant power setting: when you change
> trim, do you adjust the yoke (or joystick)
> position to keep things straight and level?

Only if the trim adjustment puts me out of trim. Then I have to hold the yoke
continuously. If I gradually trim correctly, I can apply less and less
pressure to the yoke.

> I thought so. Do you see the problem?

Not really. It's a bit like saying the simulation isn't realistic because it
uses a stick instead of a yoke. The difference between a stick and yoke is
trivial.

--
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[[email protected]]

In rec.aviation.piloting Mxsmanic > wrote:
> Just go look it up! writes:

> > Even more basically, if the servo didn't care about pressure then why
> > would it have a feedback generator to tell the trim servo just how
> > much adjustments it needs?

> Different autopilots work in different ways. The autopilot maintains altitude,
> or heading; it does not relieve control pressure. If the aircraft is
> perfectly trimmed at 5000 feet and you set the autopilot for 4000 feet, the
> autopilot will adjust trim (in APs that work this way) despite the absence of
> any control pressure. An autopilot looks at instrument readings, not control
> pressures--some aircraft don't even have control pressures.

Your understanding of real autopilots is extremely simplistic and
incorrect.

All real aircraft piloted by humans have control pressure, including
aircraft with fly-by-wire systems.

--
Jim Pennino

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[[email protected]]

In rec.aviation.piloting Mxsmanic > wrote:
> Gig 601XL Builder writes:

> > They don't because they don't have emotions. But the owners of the A/P do
> > care because if the A/P servo is having to fight the control pressure it is
> > also going to wear out sooner.

> If the servo actuates the control column.

If the servo is controlling the control surface, it is hooked into the
cable or hydraulics that the yoke controls.

All real aircraft have elevator trim.

<snip>

--
Jim Pennino

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[[email protected]]

In rec.aviation.piloting Mxsmanic > wrote:
> writes:

> > You're demonstrating that you've never been in a real
> > plane, nor even in a good simulator ("good" meaning
> > one that simulates control pressure).

> Some people here have only been in one type of aircraft, and mistakenly
> believe that all aircraft are the same.

> > Anyway, if you're trimmed for a very slow
> > airspeed, (high AoA, nose-up pitch) you'll
> > absolutely know it. You'll know it by the sloppy
> > feel of the controls, the sound the plane makes,
> > and your airspeed indicator. Likewise, if you're
> > trimmed for a very high airspeed, you'll know
> > it by the stiff controls, the sound, and the
> > airspeed indicator.

> In some aircraft, yes. But I wouldn't trust that in all aircraft.

That's because you have never been in a real airplane.

Other than maybe something exotic like a SR-71, they ALL do that.

--
Jim Pennino

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[[email protected]]

In rec.aviation.piloting Mxsmanic > wrote:
> writes:

> > Then back off the appropriate number of notches.

> How many notches?

A couple.

--
Jim Pennino

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[Mxsmanic]

writes:

> Your understanding of real autopilots is extremely simplistic and
> incorrect.

Explain the errors.

> All real aircraft piloted by humans have control pressure, including
> aircraft with fly-by-wire systems.

Most, rather than all. And in some aircraft the pressure is simulated, simply
because the pilot expects it. Obviously, it wouldn't make sense to simulate
control pressure and then use that to control an autopilot. Besides, as I've
said, autopilots don't exist for the purpose of relieving control pressures.

--
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[Mxsmanic]

writes:

> All real aircraft have elevator trim.

Not true. Some move the stabilizer instead. The difference is significant
because moving the stabilizer conserves the entire operating range of the
elevator, whereas moving the elevator with a trim tab does not.

--
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[Mxsmanic]

writes:

> That's because you have never been in a real airplane.

No, it's because I know that there are many different types of airplane, and
that such generalizations are not universally applicable in consequence.

> Other than maybe something exotic like a SR-71, they ALL do that.

I wonder if a pilot who had flown only SR-71s would insist that all aircraft
have unstarts.

--
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[Mxsmanic]

writes:

> A couple.

How many is that? Didn't you say that real pilots learn this during their
training?

--
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[[email protected]]

In rec.aviation.piloting Mxsmanic > wrote:
> writes:

> > Your understanding of real autopilots is extremely simplistic and
> > incorrect.

> Explain the errors.

Why, you'll just argue about it?

> > All real aircraft piloted by humans have control pressure, including
> > aircraft with fly-by-wire systems.

> Most, rather than all. And in some aircraft the pressure is simulated, simply
> because the pilot expects it. Obviously, it wouldn't make sense to simulate
> control pressure and then use that to control an autopilot. Besides, as I've
> said, autopilots don't exist for the purpose of relieving control pressures.

Read my above sentence slowly and carefully.

Nowhere in there did I say anything about where the control pressure
comes from.

While it is true that "autopilots don't exist for the purpose of
relieving control pressures", it is also true that ice cream has no
bones.

Neither statement has anything to do with how autopilots work.

--
Jim Pennino

Remove .spam.sux to reply.

[[email protected]]

In rec.aviation.piloting Mxsmanic > wrote:
> writes:

> > That's because you have never been in a real airplane.

> No, it's because I know that there are many different types of airplane, and
> that such generalizations are not universally applicable in consequence.
>
> > Other than maybe something exotic like a SR-71, they ALL do that.

> I wonder if a pilot who had flown only SR-71s would insist that all aircraft
> have unstarts.

Probably not, but he would agree with the previous poster's statements
you snipped out.

--
Jim Pennino

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[[email protected]]

In rec.aviation.piloting Mxsmanic > wrote:
> writes:

> > A couple.

> How many is that? Didn't you say that real pilots learn this during their
> training?

I already gave you the definition of "couple".

Have you forgotten it already?

Is your native lanuage something other than English?

--
Jim Pennino

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[Mxsmanic]

writes:

> Why, you'll just argue about it?

Only if your explanation is unsatisfactory.

--
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[Mxsmanic]

writes:

> I already gave you the definition of "couple".
>
> Have you forgotten it already?
>
> Is your native lanuage something other than English?

Put more simply, the amount by which the mixture must be adjusted in a
specific aircraft for specific conditions is _not_ a part of the training of
real pilots, contrary to the assertion made along those lines. QED.

--
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[Rip]

Mxsmanic wrote:

> writes:
>
>
>>I already gave you the definition of "couple".
>>
>>Have you forgotten it already?
>>
>>Is your native lanuage something other than English?
>
>
> Put more simply, the amount by which the mixture must be adjusted in a
> specific aircraft for specific conditions is _not_ a part of the training of
> real pilots, contrary to the assertion made along those lines. QED.
>
Incorrect. Nor are you qualified to gainsay me, as you have no aviation
experience. The end.

[[email protected]]

In rec.aviation.piloting Mxsmanic > wrote:
> writes:

> > Why, you'll just argue about it?

> Only if your explanation is unsatisfactory.

Now you are argueing about argueing...

--
Jim Pennino

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[Snowbird]

"Mxsmanic" wrote ...
>
>> Autopilots certainly want to trim out control pressure. Think about what
>> would otherwise happen when you disconnect the autopilot. Duh.
>
> It actually _does_ happen when you disconnect the autopilot, in some
> aircraft.
> The purpose of the autopilot is not to relieve control pressure, it is to
> fly
> the aircraft. In aircraft that use trim for the autopilot, the aircraft
> may
> be stable when you turn the autopilot off. However, in aircraft that
> directly
> manipulate the controls with the autopilot, the aircraft may suddenly
> change
> attitude when the AP is shut off, if the AP has been compensating for
> something (such as an engine failure)

.... which implies control pressure ...

> while it has been operating. This has
> caused accidents.
>
I can see you have actually begun to learn something about autopilots. There
is more to the story, though. Would you believe some autopilots act on both
the control surface and the trim device?

[Mxsmanic]

Snowbird writes:

> I can see you have actually begun to learn something about autopilots. There
> is more to the story, though. Would you believe some autopilots act on both
> the control surface and the trim device?

There are several ways to implement an autopilot. But no autopilot is
designed to relieve control pressures.

--
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[[email protected]]

In rec.aviation.piloting Mxsmanic > wrote:
> Snowbird writes:

> > I can see you have actually begun to learn something about autopilots. There
> > is more to the story, though. Would you believe some autopilots act on both
> > the control surface and the trim device?

> There are several ways to implement an autopilot. But no autopilot is
> designed to relieve control pressures.

Another true but worthless statement.

An autopilot is designed to control an airplane.

As a side effect of the design purpose, it will relieve control pressure.

--
Jim Pennino

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[Snowbird]

"Mxsmanic" wrote ...
>
> There are several ways to implement an autopilot. But no autopilot is
> designed to relieve control pressures.
>

What do you think this one does?

"The FCCs also operate together to provide the automatic pitch trim
function. The FCCs sense torque on the primary pitch servo and generate arm
and command signals to drive the pitch trim servo or external trim control
system."

Duh.

[Mxsmanic]

writes:

> As a side effect of the design purpose, it will relieve control pressure.

Not on all aircraft.

--
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[Mxsmanic]

Snowbird writes:

> What do you think this one does?
>
> "The FCCs also operate together to provide the automatic pitch trim
> function. The FCCs sense torque on the primary pitch servo and generate arm
> and command signals to drive the pitch trim servo or external trim control
> system."

It maintains altitude.

--
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[[email protected]]

In rec.aviation.piloting Mxsmanic > wrote:
> writes:

> > As a side effect of the design purpose, it will relieve control pressure.

> Not on all aircraft.

Another correct but worthless statement.

As a side effect of the design purpose, an autopilot will relieve control
pressure for the surfaces that have control trim tabs.

--
Jim Pennino

Remove .spam.sux to reply.

[[email protected]]

In rec.aviation.piloting Mxsmanic > wrote:
> Snowbird writes:

> > What do you think this one does?
> >
> > "The FCCs also operate together to provide the automatic pitch trim
> > function. The FCCs sense torque on the primary pitch servo and generate arm
> > and command signals to drive the pitch trim servo or external trim control
> > system."

> It maintains altitude.

Or maintains a rate of climb, or maintains a rate of descent, and as
a side effect of that relieves control pressure.

--
Jim Pennino

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[Maxwell]

> wrote in message
...
> In rec.aviation.piloting Mxsmanic > wrote:
>> writes:
>
>> > As a side effect of the design purpose, it will relieve control
>> > pressure.
>
>> Not on all aircraft.
>
> Another correct but worthless statement.
>
> As a side effect of the design purpose, an autopilot will relieve control
> pressure for the surfaces that have control trim tabs.
>

He is beginning to sound a lot like a washed out tech from the Microsoft
help desk, isn't he.

[Bertie the Bunyip]

On Apr 14, 3:21 am, Mxsmanic > wrote:
> writes:
> > I already gave you the definition of "couple".
>
> > Have you forgotten it already?
>
> > Is your native lanuage something other than English?
>
> Put more simply, the amount by which the mixture must be adjusted in a
> specific aircraft for specific conditions is _not_ a part of the training of
> real pilots, contrary to the assertion made along those lines.


Yes, actually, it is, fjukktard.



Bertie

[Maxwell]

"Mxsmanic" > wrote in message
...
>
> Put more simply, the amount by which the mixture must be adjusted in a
> specific aircraft for specific conditions is _not_ a part of the training
> of
> real pilots, contrary to the assertion made along those lines. QED.
>

Priceless!

Yeah, you're right dip****, leaning is not covered until the ATP coarse.

[[email protected]]

In rec.aviation.piloting Maxwell > wrote:

> > wrote in message
> ...
> > In rec.aviation.piloting Mxsmanic > wrote:
> >> writes:
> >
> >> > As a side effect of the design purpose, it will relieve control
> >> > pressure.
> >
> >> Not on all aircraft.
> >
> > Another correct but worthless statement.
> >
> > As a side effect of the design purpose, an autopilot will relieve control
> > pressure for the surfaces that have control trim tabs.
> >

> He is beginning to sound a lot like a washed out tech from the Microsoft
> help desk, isn't he.

Yep; if it isn't in the script he's currently reading, he's lost.

--
Jim Pennino

Remove .spam.sux to reply.

[[email protected]]

In rec.aviation.piloting Mxsmanic > wrote:
> writes:

> > I already gave you the definition of "couple".
> >
> > Have you forgotten it already?
> >
> > Is your native lanuage something other than English?

> Put more simply, the amount by which the mixture must be adjusted in a
> specific aircraft for specific conditions is _not_ a part of the training of
> real pilots, contrary to the assertion made along those lines. QED.

You have been given the procedure to use when leaning an aircrft
engine in lieu of a POH procedure or engine instrumentation.

It is used.

It works.

Every real pilot learns it.

Your inability to understand common words and phrases such as "maximum",
"a couple", "may", and "must" is irrelevant to how real pilots lean
engines on real airplanes.

You are a blathering idiot. QED.


--
Jim Pennino

Remove .spam.sux to reply.

[Maxwell]

"Mxsmanic" > wrote in message
...
> writes:
>
>> You're demonstrating that you've never been in a real
>> plane, nor even in a good simulator ("good" meaning
>> one that simulates control pressure).
>
> Some people here have only been in one type of aircraft, and mistakenly
> believe that all aircraft are the same.
>
>> Anyway, if you're trimmed for a very slow
>> airspeed, (high AoA, nose-up pitch) you'll
>> absolutely know it. You'll know it by the sloppy
>> feel of the controls, the sound the plane makes,
>> and your airspeed indicator. Likewise, if you're
>> trimmed for a very high airspeed, you'll know
>> it by the stiff controls, the sound, and the
>> airspeed indicator.
>
> In some aircraft, yes. But I wouldn't trust that in all aircraft.
>

How would you know, you can find your fat ass with both hands just reading
the regs.

[Snowbird]

"Mxsmanic" wrote ...
>

Well, you really go to great lengths to demonstrate your stupidity. I wonder
why?

Let me recall the context of my question, which you cut out:

>>> There are several ways to implement an autopilot. But no autopilot is
>>> designed to relieve control pressures.
>
>> What do you think this one does?
>>
>> "The FCCs also operate together to provide the automatic pitch trim
>> function. The FCCs sense torque on the primary pitch servo and generate
>> arm
>> and command signals to drive the pitch trim servo or external trim
>> control
>> system."

Then you answer with:

>
> It maintains altitude.
>

Your answer is
a) out of context,
b) erroneous, being seriously incomplete,
c) demonstrates an attitude of trying to use convenient part-truths to
argument your viewpoint even when it has already lost. A not unknown
debating tactic, but useless nevertheless.

[Just go look it up!]

On Sat, 14 Apr 2007 16:25:02 GMT, wrote:

>In rec.aviation.piloting Mxsmanic > wrote:
>> Snowbird writes:
>
>> > I can see you have actually begun to learn something about autopilots. There
>> > is more to the story, though. Would you believe some autopilots act on both
>> > the control surface and the trim device?
>
>> There are several ways to implement an autopilot. But no autopilot is
>> designed to relieve control pressures.
>
>Another true but worthless statement.

Hmm... Is it a true statement though? The King autopilots (and the
S-Tec range AFAIK) both are designed such that they use pitch servos
to reposition the control surface (elevator or stabilator) to affect
a change (climb, descent) and have inbuilt feedback generators to tell
the trim servo to actuate such that it removes the load from the
surface at its new position. That seems to be at least two systems
who's basic design incorporates a methodology to actively relieve
control pressures.

[[email protected]]

In rec.aviation.piloting Just go look it up! > wrote:
> On Sat, 14 Apr 2007 16:25:02 GMT, wrote:

> >In rec.aviation.piloting Mxsmanic > wrote:
> >> Snowbird writes:
> >
> >> > I can see you have actually begun to learn something about autopilots. There
> >> > is more to the story, though. Would you believe some autopilots act on both
> >> > the control surface and the trim device?
> >
> >> There are several ways to implement an autopilot. But no autopilot is
> >> designed to relieve control pressures.
> >
> >Another true but worthless statement.

> Hmm... Is it a true statement though? The King autopilots (and the
> S-Tec range AFAIK) both are designed such that they use pitch servos
> to reposition the control surface (elevator or stabilator) to affect
> a change (climb, descent) and have inbuilt feedback generators to tell
> the trim servo to actuate such that it removes the load from the
> surface at its new position. That seems to be at least two systems
> who's basic design incorporates a methodology to actively relieve
> control pressures.

You are being realistic and practical in your interpretation.

He is being a pendantic, semantic game playing, asshole in he's interpretation.

Strictly, he is correct.

Autopilots are designed to control aircraft.

--
Jim Pennino

Remove .spam.sux to reply.

[Just go look it up!]

On Sat, 14 Apr 2007 23:25:04 GMT, wrote:

>In rec.aviation.piloting Just go look it up! > wrote:
>> On Sat, 14 Apr 2007 16:25:02 GMT, wrote:
>
>> >In rec.aviation.piloting Mxsmanic > wrote:

>> >> There are several ways to implement an autopilot. But no autopilot is
>> >> designed to relieve control pressures.
>> >
>> >Another true but worthless statement.
>
>> Hmm... Is it a true statement though? The King autopilots (and the
>> S-Tec range AFAIK) both are designed such that they use pitch servos
>> to reposition the control surface (elevator or stabilator) to affect
>> a change (climb, descent) and have inbuilt feedback generators to tell
>> the trim servo to actuate such that it removes the load from the
>> surface at its new position. That seems to be at least two systems
>> who's basic design incorporates a methodology to actively relieve
>> control pressures.
>
>You are being realistic and practical in your interpretation.
>
>He is being a pendantic, semantic game playing, asshole in he's interpretation.
>

Ah. Yes, he does have the propensity to do that doesn't he. And he
changes the pedantry context even within the thread he's ruining. Like
in this one, yea, autopilots control aircraft but his statement that
"no autopilot is designed to relieve control pressures" in the context
of the subthread could be parsed as "no autopilot is designed (with a
mechanism) to relieve control pressures", rather than the ultimate
design goal of an autopilot system, and he switches back and forth to
suit whichever asinine argument he's proffering at the moment.....

[ManhattanMan]

Just go look it up! wrote:
> design goal of an autopilot system, and he switches back and forth to
> suit whichever asinine argument he's proffering at the moment.....

And everybody sucks it up like a sponge, responding to the troll just like
he wants....

[Mxsmanic]

Just go look it up! writes:

> Hmm... Is it a true statement though? The King autopilots (and the
> S-Tec range AFAIK) both are designed such that they use pitch servos
> to reposition the control surface (elevator or stabilator) to affect
> a change (climb, descent) and have inbuilt feedback generators to tell
> the trim servo to actuate such that it removes the load from the
> surface at its new position. That seems to be at least two systems
> who's basic design incorporates a methodology to actively relieve
> control pressures.

Relieving control pressure is still not the purpose of the autopilot, though.
It merely uses that as a means to an end.

If autopilots were really intended to relieve control pressures, then they
would not hold altitude or heading. Instead, they would act to keep the
controls in whatever position you last put them in, irrespective of altitude
or heading. I don't know of any autopilot that does that. The closest
approach is the control-wheel steering feature of some AFDS systems on large
transport aircraft, but apparently pilots don't use those features very often,
and it's still based on maintaining something other than control pressures.

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

[Bertie the Bunyip[_2_]]

Mxsmanic > wrote in
:

> Snowbird writes:
>
>> Autopilots certainly want to trim out control pressure. Think about
>> what would otherwise happen when you disconnect the autopilot. Duh.
>
> It actually _does_ happen when you disconnect the autopilot, in some
> aircraft. The purpose of the autopilot is not to relieve control
> pressure, it is to fly the aircraft. In aircraft that use trim for
> the autopilot, the aircraft may be stable when you turn the autopilot
> off. However, in aircraft that directly manipulate the controls with
> the autopilot, the aircraft may suddenly change attitude when the AP
> is shut off, if the AP has been compensating for something (such as an
> engine failure) while it has been operating. This has caused
> accidents.

You have no idea what you're talking about, fjukktard.



Bertie

[Bertie the Bunyip[_2_]]

Mxsmanic > wrote in
:

> writes:
>
>> All real aircraft have elevator trim.
>
> Not true. Some move the stabilizer instead.

That's stil trim, you moron.


Berti e

[Bertie the Bunyip[_2_]]

Mxsmanic > wrote in
:

> writes:
>
>> Assuming you're in straight and level flight,
>> with constant power setting: when you change
>> trim, do you adjust the yoke (or joystick)
>> position to keep things straight and level?
>
> Only if the trim adjustment puts me out of trim. Then I have to hold
> the yoke continuously. If I gradually trim correctly, I can apply
> less and less pressure to the yoke.

You can't do any of the above.

You can't fly.


Bertie

[Bertie the Bunyip[_2_]]

Mxsmanic > wrote in
:

> EridanMan writes:
>
>> FWIW, Trim was the single largest aspect of aircraft piloting that my
>> simulation experience simply did not prepare me for... I mean, the
>> concept is there, but how often you need it and why simply never came
>> across clearly.
>
> I suppose so ... but how long did it take you to learn to adjust trim
> by relieving pressure on the yoke? Thirty seconds? Three minutes?
>
>> I've never experienced a simulated aircraft control that didn't have
>> a substantial dead spot in the middle and feel extremely artificial.
>
> Well, you have to look at it a different way. On a (PC) sim, the
> "dead spot" actually corresponds to "zero control pressure," or at
> least that's how it usually seems to work (I think it depends on how
> the aircraft is modeled, but good add-ons work this way). In other
> words, you can trim by holding the yoke or joystick away from its
> neutral position and then trimming until you can leave the joystick in
> the neutral position. This is very similar to relieving control
> pressure. The joystick of the sim does not use absolute positioning.
>
>> Also, I'm reasonably sure that yoke forces are exponential, rather
>> than linear, and that this plays a large roll in the 'feel issue'...
>> Something to consider.
>
> I don't know. It would be interesting to see the curves of spring
> resistance plotted against the forces exerted on the yoke when out of
> trim.
>
>> I wouldn't fret about that... the main mechanism the pilot's use to
>> handle phugoid oscillations isn't available to you (yoke pressure),
>> so your operating at an understandable disadvantage there.
>
> Better for it to be harder than easier. It means that flying the real
> thing would be easy compared to flying the sim.
>
>> My guess is that this actually has more to do with the FS 747 model
>> loosing accuracy at the limit's of the aircraft's envelope.
>
> I'm not so sure. The 747-400 has a custom-written model that is
> independent of MSFS. They supposedly spent years working on it. But
> nobody flies 747s at 2000 feet and 355 knots in real life (I think),
> so it doesn't matter that much. The oscillation was very small, but
> you can "feel" that the aircraft is oscillating a bit in watching the
> instruments.
>
>> I would imagine most simulation makers would choose to optimize
>> the model to provide the most realistic behavior for the portions of
>> the aircraft envelope that sim pilots will spend most of their time
>> in, but this will come at a cost of poorer simulation of the
>> extremes.
>
> But is low altitude and high speed really an extreme, or just
> different?
>
>> Raises an interesting question as to how AP's deal with phugoid
>> oscillations, I have no idea.
>
> I presume they work predictively, by calculation how much correction
> to apply ahead of the aircraft. Pilots can't do this as well.
>
> It's like having a weight swinging on a chain: If you try to
> compensate for the swinging reactively, it takes forever to get it to
> stop. But if you anticipate the movement of the weight and compensate
> for it as it happens, you can get the weight to stop swinging entirely
> in one or two swings.
>
>> I'll say it again though - there is no more 'neutral trim' than there
>> is a 'neutral AOA' as far as the pilot is concerned, by simple,
>> fundamental definition. The mechanisms behind the trim are not our
>> concern, what matters to us is that the aircraft provides a mechanism
>> to remove yoke pressure throughout the aircraft's operating range.
>> Period.
>
> I can't agree. If you pull the yoke way back and then trim to
> eliminate yoke pressure, you're not at all in the same state you'd be
> in if you had the yoke pretty much in a middle position and then
> trimmed to that. In the former case, you're close to the end of
> travel for the control surface; in the latter case, you have plenty of
> margin for movement in both directions.
>
> If you've trimmed for a lot of nose-up pitch and you suddenly decide
> you need more, you may find that none is left. If you trim for a more
> neutral pitch, there's plenty there when you need it. Trimming for
> extreme pitch attitudes could lull you into thinking that you are
> further from the extremes of pitch than you actually are.
>
> This is why I'm hesitant to trim for extreme pitch attitudes. I want
> to be reminded that the pitch is still fairly extreme. If I just trim
> the yoke pressure away, I might forget.
>
>> This actually suggests to me that the 'neutral trim' position your
>> aircraft provides is actually a bit behind Vy (closer to Vx?)
>
> I don't know. What I do know is that zero on the trim indicator
> corresponds to neutral trim in that the trim tabs are flush with the
> elevator.
>
>> That's like saying you should always fly in the middle of the
>> aircrafts airspeed envelope because it gives you the most options to
>> speed up or slow down... its somewhat irrelevant to the point of
>> having an aircraft that can operate in a wide envelope.
>>
>> If the aircraft is well designed, you should have full control
>> authority at any trimmed AOA.
>
> That isn't possible if you are using trim tabs; it's possible if the
> entire stabilizer moves. If you have tabs, the tabs move the control
> surface, but the range of movement of that surface does not change.
> So if you trim such that the surface moves towards one of its
> extremes, the remaining authority at that extreme is reduced.
>
> I suppose that in small aircraft the position of the yoke after
> trimming gives you a visual indication of the actual position of the
> control surfaces. My concern, though, is that you might apply a lot
> of trim and then forget that you have done so, and when you then try
> to push or pull the yoke you find that you've already trimmed out most
> of the movement of the control surface, leaving you with very little
> margin. But perhaps if you can see the yoke move, this is less of a
> problem.
>
>> Without the necessary tactile inputs, this may be somewhat futile.
>
> Why? If it works on the sim, it willl work in real life, even though
> real life may also offer a simpler method.

No it won't moron.

Bertie

[Bertie the Bunyip[_2_]]

Mxsmanic > wrote in
:

> writes:
>
>> Then why bother asking how real airplanes fly?
>
> I know how real airplanes fly.

No, you don't.


Bertie