Mechanics of Elevator Trim. In Detail.

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, 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-

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 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.

-Robert

"Robert M. Gary" wrote in news:3a16db2f-b15a-4ae5-ab8c-
:

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.

-Robert



But Le Claud Chapin has already demonstated that with his limited reading
he knows all about aviation. Don't confuse him with mere facts such as
different trim mechanisms. It will destroy his illusion of superiority in
understanding how he, not yet a pilot, better understands the mechanics of
aviation that those of us who are pilots.

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.

-Le Chaud Lapin-

"Le Chaud Lapin" wrote in message
...
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)?

--
Geoff
The Sea Hawk at Wow Way d0t Com
remove spaces and make the obvious substitutions to reply by mail
When immigration is outlawed, only outlaws will immigrate.

On Jun 9, 7:29*am, "Capt. Geoffrey Thorpe" The Sea Hawk At Wow Way
D0t C0m wrote:
"Le Chaud Lapin" wrote in ...
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)?


Why not? It woul be ejucational.

Cheers

On Jun 9, 7:29*am, "Capt. Geoffrey Thorpe" The Sea Hawk At Wow Way
D0t C0m wrote:
"Le Chaud Lapin" wrote in ...
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?

Cheers