Mechanics of Elevator Trim. In Detail.

On Jun 8, 6:06*pm, wrote:
On Jun 8, 3:39 pm, More_Flaps wrote:

A very detailed responsed mostly snipped...

Since you response is very detailed, more than I was expecting, I
should say that I was primarily interested answers about why it is
that setting trim relieves pressure that pilot has to exert on yoke.

I mentioned in response to Geoffrey's post that aircraft under
question could be consider C172, whose trim mechanism is obvious, but
if one were to talk too much about that part which is obvious, then
one might inadvertently give the answer away.

Again, this isn't rocket science, but I suspect that other students,
like I, had misconception of how it might work, even though it is
written in the book how it should work.

-Le Chaud Lapin-

Le Chaud Lapin wrote in
:

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 woul
d
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.

If there's anyone williing to take a bet....


Bertie

On Jun 8, 9:17*pm, Michael Henry
wrote:
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.../articles/0209...

Yikes - that's it. The answer is in that link.

Since no other students responded...

...when I first started used/read about trim tab, I figured it was
"more of the same", meaning that there was some complex mechanism in
the aircraft where trim tab simply did more of whatever the elevator
was doing, but some how figured out how to release pressure on the
yoke.

Well that's true, but a more correct interpretation is that the trim
tab does not participate in elevating the aircraft really, but serves
to aerodynamically set the angle of the elevator, at which point the
elevator does its job. I learn this in MSFS by trying various
movements and watching outside the aircraft how control surfaces
responded. The trim tab was moving in opposite direction that I
thought it would. I also saw that on C172, there is an asymmetric,
with only one tab.

All obvious to pilots, but interesting for students, for me at least.

-Le Chaud Lapin-

Le Chaud Lapin wrote wrote:


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-

to which I would point out that in 2008 most engineers when
considering structures operating at general aviation speeds and
stresses would be thinking of composites and molding complex shapes,
not in terms of bending metal and welded joining.

It happens that Le Chaud Lapin formulated :
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-

hahhahahaha

ploink

Hi.

In article ,
Le Chaud wrote:
Again, this isn't rocket science, but I suspect that other students,
like I, had misconception of how it might work, even though it is
written in the book how it should work.

A student who's actually sat in an aircraft and carried out the pre-flight
should have little doubt as to what moving the trim wheel actually does.

In the Warrior I fly, we're taught to put in full back elevator, then wind
the trim through the limits of its travel, watching the trim tab to ensure
it moves as it should.

Similarly, in the 'Aircraft General and Principles of Flight' exam we have
to sit in the UK, the operation of trim is expected to be understood.

Andy

On Sun, 8 Jun 2008 22:24:07 -0700 (PDT), Le Chaud Lapin
wrote:

On Jun 8, 9:17*pm, Michael Henry
wrote:
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.../articles/0209...

Yikes - that's it. The answer is in that link.

Since no other students responded...

...when I first started used/read about trim tab, I figured it was
"more of the same", meaning that there was some complex mechanism in
the aircraft where trim tab simply did more of whatever the elevator
was doing, but some how figured out how to release pressure on the
yoke.

Well that's true, but a more correct interpretation is that the trim
tab does not participate in elevating the aircraft really, but serves
to aerodynamically set the angle of the elevator, at which point the
elevator does its job. I learn this in MSFS by trying various
movements and watching outside the aircraft how control surfaces
responded. The trim tab was moving in opposite direction that I
thought it would. I also saw that on C172, there is an asymmetric,
with only one tab.

All obvious to pilots, but interesting for students, for me at least.

-Le Chaud Lapin-

if you ever read 'Stick and Rudder' by wolfgang langeweische you will
find that he refers to flippers for the majority of the book.
this is to prevent the mistake you make above where you thought the
elevator elevated the aircraft.

amazing, I never thought anyone actually made that mistake.
Stealth Pilot

Stealth Pilot wrote in
:

On Sun, 8 Jun 2008 22:24:07 -0700 (PDT), Le Chaud Lapin
wrote:

On Jun 8, 9:17*pm, Michael Henry
wrote:
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.../articles/0209
...

Yikes - that's it. The answer is in that link.

Since no other students responded...

...when I first started used/read about trim tab, I figured it was
"more of the same", meaning that there was some complex mechanism in
the aircraft where trim tab simply did more of whatever the elevator
was doing, but some how figured out how to release pressure on the
yoke.

Well that's true, but a more correct interpretation is that the trim
tab does not participate in elevating the aircraft really, but serves
to aerodynamically set the angle of the elevator, at which point the
elevator does its job. I learn this in MSFS by trying various
movements and watching outside the aircraft how control surfaces
responded. The trim tab was moving in opposite direction that I
thought it would. I also saw that on C172, there is an asymmetric,
with only one tab.

All obvious to pilots, but interesting for students, for me at least.

-Le Chaud Lapin-

if you ever read 'Stick and Rudder' by wolfgang langeweische you will
find that he refers to flippers for the majority of the book.
this is to prevent the mistake you make above where you thought the
elevator elevated the aircraft.

amazing, I never thought anyone actually made that mistake.

First hour students do sometimes. I've also seen one guy actually tilt
his head back when IO told him to raise the nose on a first flight.

Flippers is an archaic term that predates Langeweisch by a couple of
decades! It was pretty much dropped mainstream during WW2, I suppose
because it didn't sound techie enough.


Bertie

On Jun 9, 12:34*am, Tina wrote:
Le Chaud Lapin wrote wrote:



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-

to which I would point out that in 2008 most engineers when
considering structures operating at general aviation speeds and
stresses would be thinking of composites and molding complex shapes,
not in terms of bending metal and welded joining.

This presumes that you know what the welds are for, which would be
difficult, as the welders themselves do not even know at this point.

-Le Chaud Lapin-

On Jun 8, 10:20*am, Le Chaud Lapin wrote:
On Jun 8, 11:07*am, "Robert M. Gary" wrote:

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

What does MSFS have to do with anything. This is a pilot news group,
not sim. There are sim groups out there that would be more appropriate
for your question.

-Robert,CFII