Mechanics of Elevator Trim. In Detail.

On Jun 8, 3:08*pm, Le Chaud Lapin wrote:
Hi All,

This post is primarily directed toward student pilots like myself.

First, I am not asking because I want to know the answer (I already
know), but do a little experiment. *I have maybe 7 or 8 different
sources of flight information that I rely on for ground school
(Jeppesen, FAA Handbooks, etc), and none of them said _how_ it worked
in sufficient detail, they only said what one must do to make the
plane pitch up or downard.

So for you students, please do not cheat and do what I did, which is
watch the airfoils move as you move the trim control. *Also, it would
help if you did not think about the correct answer too much, which
would lead you to the correct answer, thereby defeating the purpose of
my experiment.

So, without cheating, and without asking an experienced pilot or
mechanic,...

What exactly happens when the trim is adjusted to point the nose
upward?

The more specific your answer about the mechanics on airfoil outside
the plane, the better.

And remember, no cheating!

Also, for experienced pilots that know the answer, please do not ruin
it by telling everyone before any answers have been given, though if
you are not certain of the answer and would like to speculate, that's
fine.

Are you sure you are not Mxsmanic? You are asking a question and you
dont want anybody who knows the answer to reply. In other words you
want people to answer incorrectly so you can correct them, correct?
Only difference between that and Mxsmanic is that he will correct you
whether you are right or wrong.
I trust you will only correct those that are really incorrect,
correct?
So Le Chaud, have you actually started your flying training yet?
congratulations if you have and I look forward to hearing how it is
going.
Terry
PPL Downunder

On Jun 8, 5:40 pm, terry wrote:
On Jun 8, 3:08 pm, Le Chaud Lapin wrote:



Hi All,

This post is primarily directed toward student pilots like myself.

First, I am not asking because I want to know the answer (I already
know), but do a little experiment. I have maybe 7 or 8 different
sources of flight information that I rely on for ground school
(Jeppesen, FAA Handbooks, etc), and none of them said _how_ it worked
in sufficient detail, they only said what one must do to make the
plane pitch up or downard.

So for you students, please do not cheat and do what I did, which is
watch the airfoils move as you move the trim control. Also, it would
help if you did not think about the correct answer too much, which
would lead you to the correct answer, thereby defeating the purpose of
my experiment.

So, without cheating, and without asking an experienced pilot or
mechanic,...

What exactly happens when the trim is adjusted to point the nose
upward?

The more specific your answer about the mechanics on airfoil outside
the plane, the better.

And remember, no cheating!

Also, for experienced pilots that know the answer, please do not ruin
it by telling everyone before any answers have been given, though if
you are not certain of the answer and would like to speculate, that's
fine.

Are you sure you are not Mxsmanic? You are asking a question and you
dont want anybody who knows the answer to reply. In other words you
want people to answer incorrectly so you can correct them, correct?
Only difference between that and Mxsmanic is that he will correct you
whether you are right or wrong.
I trust you will only correct those that are really incorrect,
correct?
So Le Chaud, have you actually started your flying training yet?
congratulations if you have and I look forward to hearing how it is
going.
Terry
PPL Downunder

Terry, it might have been a few months ago that someone using this
username was going to use his engineering degree to design a superior
g a airplane. He did promise progress reports.

I am afraid he may be a fraud.

All who are surprised please raise their hands.

No hands? I'd say that makes him an unsuccessful fraud.

on 6/8/2008 4:39 PM More_Flaps said the following:
On Jun 9, 9:24 am, Bertie the Bunyip wrote:
More_Flaps wrote :





On Jun 9, 9:06 am, Bertie the Bunyip wrote:
More_Flaps wrote
innews:64b157a9-99f5-4429-9125-d1e2
:
On Jun 9, 7:29 am, "Capt. Geoffrey Thorpe" The Sea Hawk At Wow Way
D0t C0m wrote:
"Le Chaud Lapin" wrote in
messagenews:5c4deac0-2b92
...
On Jun 8, 11:07 am, "Robert M. Gary" wrote:
On Jun 7, 10:08 pm, Le Chaud Lapin wrote:
What exactly happens when the trim is adjusted to point the
nose upward?
What type of plane is this for? I have a Mooney and also fly a
182. Both trim system are very, very different.
For sake of those of us who only own MSFS, let's say a C172.
Does MSFS emulate the servo tab on the elevator? What does it do
when you change the trim in the air?
Trying to emulate real life trim on a simulation system that uses
spring centered control sticks isn't going to work like real life
as you may already know.
Should I post the spoiler on how a couple other mechanisims work
(besides servo tabs)?
I'll raise you one to make three additional trim systems. Any more?
I can think of four for a total of five, depending on whether you'd
consider hydraulic centering to be the same as a bungee trim system.
theothersa re of course, a tab system which is th emost common light
aircraft system. the trimmable stab, a'la Cub and most airliners and
the vane, like some early T-carts had.. There're probably some
others, but i can't think of any.
I'd count that as the same -the acutuating system doesn't count, just
the aerodynamic priciples. So, if you have four I'll raise you again
one to make five... Any raise on five basic methods?
Yeah, they;re essentially the same.

Go on. I'll call.

Should'nt we wait to see if there's any other raise?

Weight shift?

On Jun 9, 8:31*am, Tina wrote:
On Jun 8, 5:40 pm, terry wrote:





On Jun 8, 3:08 pm, Le Chaud Lapin wrote:

Hi All,

This post is primarily directed toward student pilots like myself.

First, I am not asking because I want to know the answer (I already
know), but do a little experiment. *I have maybe 7 or 8 different
sources of flight information that I rely on for ground school
(Jeppesen, FAA Handbooks, etc), and none of them said _how_ it worked
in sufficient detail, they only said what one must do to make the
plane pitch up or downard.

So for you students, please do not cheat and do what I did, which is
watch the airfoils move as you move the trim control. *Also, it would
help if you did not think about the correct answer too much, which
would lead you to the correct answer, thereby defeating the purpose of
my experiment.

So, without cheating, and without asking an experienced pilot or
mechanic,...

What exactly happens when the trim is adjusted to point the nose
upward?

The more specific your answer about the mechanics on airfoil outside
the plane, the better.

And remember, no cheating!

Also, for experienced pilots that know the answer, please do not ruin
it by telling everyone before any answers have been given, though if
you are not certain of the answer and would like to speculate, that's
fine.

Are you sure you are not Mxsmanic? *You are asking a question and you
dont want anybody who knows the answer to reply. *In other words you
want people to answer incorrectly so you can correct them, correct?
Only difference between that and *Mxsmanic is that he will correct you
whether you are right or wrong.
I trust you will only correct those that are really incorrect,
correct?
So Le Chaud, have you actually started your flying training yet?
congratulations if you have and I look forward to hearing how it is
going.
Terry
PPL Downunder

Terry, it might have been a few months ago that someone using this
username was going to use his engineering degree to design a superior
g a airplane. He did promise progress reports.

I am afraid he may be a fraud.

That would be a Le Fraud, but I am prepared to give him the benefit
of the doubt.
Tina, are you joining the mass exodus to pilots of america? they seem
to be a pretty friendly bunch, even welcoming an alien like me.
Terry
PPL Downunder

Tina, are you joining the mass exodus to pilots of america? they seem
to be a pretty friendly bunch, even welcoming an alien like me.
Terry
PPL Downunder

I have joined there with the unimaginative user name tina201, but have
not found my way around the site yet. I have yet to find the room that
has the same wide range of topics as this site does, but absent what
we shrinks call '****ing contests' (sorry for the technical language).
I fully admit I have not yet done more than join the site.

On Jun 8, 3:39 pm, More_Flaps wrote:
On Jun 9, 9:24 am, Bertie the Bunyip wrote:



More_Flaps wrote :

On Jun 9, 9:06 am, Bertie the Bunyip wrote:
More_Flaps wrote
innews:64b157a9-99f5-4429-9125-d1e2
:

On Jun 9, 7:29 am, "Capt. Geoffrey Thorpe" The Sea Hawk At Wow Way
D0t C0m wrote:
"Le Chaud Lapin" wrote in
messagenews:5c4deac0-2b92
...
On Jun 8, 11:07 am, "Robert M. Gary" wrote:

On Jun 7, 10:08 pm, Le Chaud Lapin wrote:

What exactly happens when the trim is adjusted to point the
nose upward?

What type of plane is this for? I have a Mooney and also fly a
182. Both trim system are very, very different.

For sake of those of us who only own MSFS, let's say a C172.

Does MSFS emulate the servo tab on the elevator? What does it do
when you change the trim in the air?

Trying to emulate real life trim on a simulation system that uses
spring centered control sticks isn't going to work like real life
as you may already know.

Should I post the spoiler on how a couple other mechanisims work
(besides servo tabs)?

I'll raise you one to make three additional trim systems. Any more?

I can think of four for a total of five, depending on whether you'd
consider hydraulic centering to be the same as a bungee trim system.
theothersa re of course, a tab system which is th emost common light
aircraft system. the trimmable stab, a'la Cub and most airliners and
the vane, like some early T-carts had.. There're probably some
others, but i can't think of any.

I'd count that as the same -the acutuating system doesn't count, just
the aerodynamic priciples. So, if you have four I'll raise you again
one to make five... Any raise on five basic methods?

Yeah, they;re essentially the same.

Go on. I'll call.

Should'nt we wait to see if there's any other raise?

Cheers

Some sailplanes, some ultralights and a few other light
aircraft use bungees or springs in the elevator control system.
Adjusting the tension of the bungee or spring will apply appropriate
force to the elevator system to achieve trim.

Tabs are most common. Some ultralights have a ground-adjustable
tab. Others use a chain-and-cable arrangement that work a small
jackscrew inside the stab that pushes and pulls a rod attached to the
tab. Cessna likes that one. Taylorcraft used a crank that drove a
cable loop that worked a pulley that had a thread through it, and ran
a screw back and forth to work a shorter push-pull cable to the tab,
IIRC. Some just use a long push-pull Bowden cable directly from a
lever to the tab. Champs/Citabrias use a lever that works two 1/16"
cables directly to the tab, via pulleys. Some homebuilts use an
electric jackscrew to work the tab. Electrical failure means no trim.

Adjustable stabilizers are not uncommon. The Supercub and Tri-
Pacer use them but also have a bungee affair that applies tension to
the elevator cables. Two systems in one airplane. The Cessna 180/185
adjusts the stab via two jackscrews at the leading edge, operated in
unison by sprockets and a chain diven by a cable loop.

I once saw somewhere a light aircraft (homebuilt ultralight, I
think) that had its battery on a sliding device that moved fore-and-
aft to change the CG and therefore trim. This sort of thing adds
unacceptable weight.

Stabilators use adjustable antiservo tabs. That tab has a lever
on it whose forward end is hinged at a point behind the stab hinge to
get the desired antiservo action, and that hinge point is on a nut
moved fore and aft by a jackscrew to get the trim action.

Mooneys used to move the WHOLE TAIL, fin and stab and all, to
change the angle of the stab. Do they still make them that way?

The Spratt Controlwing moved the wings for all control
including trim. The tail did nothing but keep the nose pointed into
the wind. See http://www.flyingflea.org/docs/SprattControlwing.htm

Didn't the Wren 260 use a small canard for low-speed trim?
http://en.wikipedia.org/wiki/Peterson_260SE

Dan

More_Flaps wrote in
:

On Jun 9, 9:24*am, Bertie the Bunyip wrote:
More_Flaps wrote
innews:d998f060-3e6a-4b62-8179-88af
:





On Jun 9, 9:06*am, Bertie the Bunyip wrote:
More_Flaps wrote
innews:64b157a9-99f5-4429-9125-d1e2
:

On Jun 9, 7:29*am, "Capt. Geoffrey Thorpe" The Sea Hawk At Wow
Way

D0t C0m wrote:
"Le Chaud Lapin" wrote in
messagenews:5c4deac0-2b92
...
On Jun 8, 11:07 am, "Robert M. Gary" wrote:

On Jun 7, 10:08 pm, Le Chaud Lapin
wrote:

What exactly happens when the trim is adjusted to point the
nose upward?

What type of plane is this for? I have a Mooney and also fly
a 182. Both trim system are very, very different.

For sake of those of us who only own MSFS, let's say a C172.

Does MSFS emulate the servo tab on the elevator? What does it
do when you change the trim in the air?

Trying to emulate real life trim on a simulation system that
uses spring centered control sticks isn't going to work like
real life as you may already know.

Should I post the spoiler on how a couple other mechanisims
work (besides servo tabs)?

I'll raise you one to make three additional trim systems. Any
more?

I can think of four for a total of five, depending on whether
you'd consider hydraulic centering to be the same as a bungee trim
system. theothersa re of course, a tab system which is th emost
common light aircraft system. the trimmable stab, a'la Cub and
most airliners and the vane, like some early T-carts had..
There're probably some others, but i can't think of any.

I'd count that as the same -the acutuating system doesn't count,
just the aerodynamic priciples. So, if you have four I'll raise you
again one to make five... Any raise on five basic methods?

Yeah, they;re essentially the same.

Go on. I'll call.


Should'nt we wait to see if there's any other raise?

Cheers

Would a 100% computer controlled system like the B2 count as yet another
way? Do they even have to trim it or does the computer automatically
adjust for whatever flight regime they set?

--
Marty Shapiro
Silicon Rallye Inc.

(remove SPAMNOT to email me)

On Jun 8, 7:06 pm, wrote:
On Jun 8, 3:39 pm, More_Flaps wrote:



On Jun 9, 9:24 am, Bertie the Bunyip wrote:

More_Flaps wrote :

On Jun 9, 9:06 am, Bertie the Bunyip wrote:
More_Flaps wrote
innews:64b157a9-99f5-4429-9125-d1e2
:

On Jun 9, 7:29 am, "Capt. Geoffrey Thorpe" The Sea Hawk At Wow Way
D0t C0m wrote:
"Le Chaud Lapin" wrote in
messagenews:5c4deac0-2b92
...
On Jun 8, 11:07 am, "Robert M. Gary" wrote:

On Jun 7, 10:08 pm, Le Chaud Lapin wrote:

What exactly happens when the trim is adjusted to point the
nose upward?

What type of plane is this for? I have a Mooney and also fly a
182. Both trim system are very, very different.

moved fore and aft by a jackscrew to get the trim action.

Mooneys used to move the WHOLE TAIL, fin and stab and all, to
change the angle of the stab. Do they still make them that way?


You're right, Dan -- through at least the Mooney 201 (M20J) there are
no trim tabs, the entire tail pivots to change the trim.

Capt. Geoffrey Thorpe wrote:

I assume you are most familiar with the use of a servo tab. Can you name
at least two other ways that it is commonly done in light aircraft?

The J-3 Cub has a moving stabilizer. Although you specifically said
"light aircraft" it's interesting to note that many airliners also us a
moving stabilizer.

This and another method are mentioned in this article:

http://flighttraining.aopa.org/learn...rticle_pf.html

On Jun 8, 5:31*pm, Tina wrote:
On Jun 8, 5:40 pm, terry wrote:





On Jun 8, 3:08 pm, Le Chaud Lapin wrote:

Hi All,

This post is primarily directed toward student pilots like myself.

First, I am not asking because I want to know the answer (I already
know), but do a little experiment. *I have maybe 7 or 8 different
sources of flight information that I rely on for ground school
(Jeppesen, FAA Handbooks, etc), and none of them said _how_ it worked
in sufficient detail, they only said what one must do to make the
plane pitch up or downard.

So for you students, please do not cheat and do what I did, which is
watch the airfoils move as you move the trim control. *Also, it would
help if you did not think about the correct answer too much, which
would lead you to the correct answer, thereby defeating the purpose of
my experiment.

So, without cheating, and without asking an experienced pilot or
mechanic,...

What exactly happens when the trim is adjusted to point the nose
upward?

The more specific your answer about the mechanics on airfoil outside
the plane, the better.

And remember, no cheating!

Also, for experienced pilots that know the answer, please do not ruin
it by telling everyone before any answers have been given, though if
you are not certain of the answer and would like to speculate, that's
fine.

Are you sure you are not Mxsmanic? *You are asking a question and you
dont want anybody who knows the answer to reply. *In other words you
want people to answer incorrectly so you can correct them, correct?
Only difference between that and *Mxsmanic is that he will correct you
whether you are right or wrong.
I trust you will only correct those that are really incorrect,
correct?
So Le Chaud, have you actually started your flying training yet?
congratulations if you have and I look forward to hearing how it is
going.
Terry
PPL Downunder

Terry, it might have been a few months ago that someone using this
username was going to use his engineering degree to design a superior
g a airplane. He did promise progress reports.

I am afraid he may be a fraud.

All who are surprised please raise their hands.

No hands? I'd say that makes him an unsuccessful fraud.- Hide quoted text -

Spent 30 minutes at pool yesterday discussing with professional
metalworkers best way to weld a complex joint for important element of
prototype of what would be considered a wing.

Such things take time, and still, I do not know if it will work.

-Le Chaud Lapin-