limit of trim = limit of travel?

On Apr 30, 9:37*am, wrote:
On Apr 29, 2:24 pm, WingFlaps wrote:

I don't follow this. The trim surface operates in the opposite
direction to the trimmed surface and takes area away from it. Explain
please?

Cheers

* * * *The trim tab generates a force that moves the trailing edge of
the control surface. So if you trim nose-up, you'll be moving the tab
downward, where it forces the elevator up.

Yes that is exactly what I said. So, does the trim actually improve
control responsiveness or not?

Cheers

WingFlaps wrote in news:ad8fc9c9-57cb-4733-9e97-
:

On Apr 30, 9:37*am, wrote:
On Apr 29, 2:24 pm, WingFlaps wrote:

I don't follow this. The trim surface operates in the opposite
direction to the trimmed surface and takes area away from it.
Explain
please?

Cheers

* * * *The trim tab generates a force that moves the trailing edge
of
the control surface. So if you trim nose-up, you'll be moving the tab
downward, where it forces the elevator up.

Yes that is exactly what I said. So, does the trim actually improve
control responsiveness or not?

Do you mean if oyu move the trim tab in the same direction as the
elevator? IN general, yes, it will.


Bertie

Cheers

On Apr 30, 11:05*am, "Peter Dohm" wrote:
"WingFlaps" wrote in message
...

I don't follow this. The trim surface operates in the opposite
direction to the trimmed surface and takes area away from it. Explain
please?

Cheers

Sorry, I misread the question and answered mainly based upon the location in
the thread.

You are correct that some effective area is taken away, but the amount of
"lost" area is small and easily taken into account in the design--whereas
the reduction of pilot workload is great. *Also, under normal conditions,
the limitation on elevator authority is the setting of the mechanical stop
rather than the area.


Ah, OK thanks.

Cheers

On Apr 30, 12:12*pm, Bertie the Bunyip wrote:
WingFlaps wrote in news:ad8fc9c9-57cb-4733-9e97-
:





On Apr 30, 9:37*am, wrote:
On Apr 29, 2:24 pm, WingFlaps wrote:

I don't follow this. The trim surface operates in the opposite
direction to the trimmed surface and takes area away from it.
Explain
please?

Cheers

* * * *The trim tab generates a force that moves the trailing edge
*of
the control surface. So if you trim nose-up, you'll be moving the tab
downward, where it forces the elevator up.

Yes that is exactly what I said. So, does the trim actually improve
control responsiveness or not?

Do you mean if oyu move the trim tab in the same direction as the
elevator? IN general, yes, it will.

Bertie


Thanks, I guess it adds a bit of camber in that direction and takes it
away in the opposite direction...

Cheers

WingFlaps wrote in news:8107e6ea-0c5c-460c-8b38-
:

On Apr 30, 12:12*pm, Bertie the Bunyip wrote:
WingFlaps wrote in news:ad8fc9c9-57cb-4733-
9e97-
:





On Apr 30, 9:37*am, wrote:
On Apr 29, 2:24 pm, WingFlaps wrote:

I don't follow this. The trim surface operates in the opposite
direction to the trimmed surface and takes area away from it.
Explain
please?

Cheers

* * * *The trim tab generates a force that moves the trailing e
dge
*of
the control surface. So if you trim nose-up, you'll be moving the
tab
downward, where it forces the elevator up.

Yes that is exactly what I said. So, does the trim actually improve
control responsiveness or not?

Do you mean if oyu move the trim tab in the same direction as the
elevator? IN general, yes, it will.

Bertie


Thanks, I guess it adds a bit of camber in that direction and takes it
away in the opposite direction...

Yes, but of course there would be exceptions. Lots of lightplanes with
stabilators have an anti balance tabe ( more commonly known,
incorrectly, as an anti servo tab) which increases authority and adds
feel to the control stick. I once flew a homebuilt Pitts that had no
tabs on the elevators at all. The pitch control was indescribably light.
Scarily light. I and others found the airplane such a handful that the
owner added a trim/anti-balance tab.

Bertie

On Apr 29, 6:12 pm, Bertie the Bunyip wrote:

Do you mean if oyu move the trim tab in the same direction as the
elevator? IN general, yes, it will.

In general. Control surface deflections are part of the type
certificate data, and it's to make sure there's enough control
authority without stalling the control surface. Too much travel would
do that, and I think that having an elevator tab full-up, say, and
then using full-up elevator, could start the tab stalling a little,
maybe enough to stall the elevator itself. Never seen it though.
I remember a story by some guy who found that his elevator was
jammed somehow and he couldn't get full up travel while in flight. He
was able to get enough authority to flare using some power and full
nose-down trim, which raised the tab and helped raise the nose, though
he had to pull pretty hard against that trim.

Dan

wrote in news:96353123-74d2-46a1-a81a-
:

On Apr 29, 6:12 pm, Bertie the Bunyip wrote:

Do you mean if oyu move the trim tab in the same direction as the
elevator? IN general, yes, it will.

In general. Control surface deflections are part of the type
certificate data, and it's to make sure there's enough control
authority without stalling the control surface. Too much travel would
do that, and I think that having an elevator tab full-up, say, and
then using full-up elevator, could start the tab stalling a little,
maybe enough to stall the elevator itself. Never seen it though.
I remember a story by some guy who found that his elevator was
jammed somehow and he couldn't get full up travel while in flight. He
was able to get enough authority to flare using some power and full
nose-down trim, which raised the tab and helped raise the nose, though
he had to pull pretty hard against that trim.



I know someone who had an elevator jam (no up) after doing aerobatics in
a glider. A Blanik. The rear seat cushion had come loose and jammed the
stick slightly forward. He managed to land using the elevator trim in
it's reverse sense. I'm sure it happened fairly often in combat in WW2.
After that it would have been all boosted controls anyway..

Bertie

"Bertie the Bunyip" wrote in message
.. .
wrote in news:96353123-74d2-46a1-a81a-
:

On Apr 29, 6:12 pm, Bertie the Bunyip wrote:

Do you mean if oyu move the trim tab in the same direction as the
elevator? IN general, yes, it will.

In general. Control surface deflections are part of the type
certificate data, and it's to make sure there's enough control
authority without stalling the control surface. Too much travel would
do that, and I think that having an elevator tab full-up, say, and
then using full-up elevator, could start the tab stalling a little,
maybe enough to stall the elevator itself. Never seen it though.
I remember a story by some guy who found that his elevator was
jammed somehow and he couldn't get full up travel while in flight. He
was able to get enough authority to flare using some power and full
nose-down trim, which raised the tab and helped raise the nose, though
he had to pull pretty hard against that trim.



I know someone who had an elevator jam (no up) after doing aerobatics in
a glider. A Blanik. The rear seat cushion had come loose and jammed the
stick slightly forward. He managed to land using the elevator trim in
it's reverse sense. I'm sure it happened fairly often in combat in WW2.
After that it would have been all boosted controls anyway..

Bertie


Sure you did Bertie, you know everyone, have done everything, have seen
everything,,,,, except the way we see you.

"Bertie the Bunyip" wrote in message
...
"Maxwell" luv2^fly99@cox.^net wrote in
:


"Buttman" wrote in message
...
Bertie the Bunyip wrote:

Buttman wrote in
:

WingFlaps wrote:

On Apr 27, 7:03 am, Mxsmanic wrote:
I just tried a few experiments

No, that doesn't sound right.
The stall horn is supposed to sound before the stall speed is
reached.

Cheers

"supposed to", but doesn't always. I've flown planes (especially
cessnas with their crappy cereal-box-toy-quality plastic stall
horns) that don't go off at all, but will test fine on the ground.


What, you didn't stick chewing gum in them to fail them so your
students would learn what it was like when they failed?

Bertie

Oh bertie, you're such a card

Na, not really. Just a self made prick.


Moi? never. Nope. I just treat people exactly as the expect to be
treated.


Fjukktard.


Bertie

So you want people to follow you around and call you a Fjukktard?

"Maxwell" luv2^fly99@cox.^net wrote in news:rG8Sj.111613$Ft5.59820
@newsfe15.lga:


"Bertie the Bunyip" wrote in message
...
"Maxwell" luv2^fly99@cox.^net wrote in
:


"Buttman" wrote in message
...
Bertie the Bunyip wrote:

Buttman wrote in
:

WingFlaps wrote:

On Apr 27, 7:03 am, Mxsmanic wrote:
I just tried a few experiments

No, that doesn't sound right.
The stall horn is supposed to sound before the stall speed is
reached.

Cheers

"supposed to", but doesn't always. I've flown planes (especially
cessnas with their crappy cereal-box-toy-quality plastic stall
horns) that don't go off at all, but will test fine on the
ground.


What, you didn't stick chewing gum in them to fail them so your
students would learn what it was like when they failed?

Bertie

Oh bertie, you're such a card

Na, not really. Just a self made prick.


Moi? never. Nope. I just treat people exactly as the expect to be
treated.


Fjukktard.


Bertie

So you want people to follow you around and call you a Fjukktard?



I don;t want them to, but they can if they like.

You recommend it do you, heroin boi?



Bertie