Vertical Stabiliser

[donnlass]

I am reading Handling The Big Jets by D P Davies at the moment and he is describing how overloading the elevator hinge can cause the stabiliser drive motor to stall.

He says that pilots should not run the stabiliser very far back before it becomes obvious they have regained pitch control of the aeroplane.

How does the vertical stabiliser work?

Is the tail mobile or is it just a motor inside that alters pitch?

I did look on google but couldnt get the answer I am after.


A typical layman question I know lol.


Also can the public access Chromo?


Thanks.

[BOAC]

It's the 'Horizontal Stabiliser' you need - Google 'Tailplane Tailplane - Wikipedia, the free encyclopedia (http://en.wikipedia.org/wiki/Tailplane) - see it that helps. I guess it is complicated for you - a 'Horizontal Stabiliser' sits Horizontally but controls Vertically:rolleyes:

A 'Vertical Stabiliser' sits vertically but controls 'horizontally':)

DP is a little out of date now in some areas. Designs have advanced a lot.

What is 'Chromo'?

[Lukeafb1]

I’m a little confused by some of the detail in your thread starter, Donnlass.

You mention “overloading the elevator hinge”, which is attached to the tailplane or vertical stabiliser. The elevators can be trimmed by internal mechanisms to reduce the forces on the elevator (and hinges) and keep the aircraft in the attitude required by the pilot/s. I’m assuming that Mr Davies means that overcontrolling by using the elevators in extreme positions, up or down may (will) cause excessive stress to the elevator hinges. However, in normal flight, doing this will result in extreme pitching of the aircraft, causing other severe problems and unless in an emergency situation, pilots would never take this course of action.

The elevators are connected (hinged) to the tailplane (or vertical stabiliser), which on some aircraft, can also be moved by jacks to trim the aircraft (i.e. trim the aircraft nose up or nose down). However, if I understand what Mr Davies is saying regarding “running the stabiliser very far back”, he appears to be saying that extreme movement of the stabilisers (i.e. trimming the stabiliser fully up or down) is not to be recommended. This would put unacceptable force on the stabiliser and could cause damage. I can’t think of any normal operation which would require extreme placement of the stabiliser (up or down) anyway.

Nor do I understand why overloading the elevators (and by definition, overloading the vertical stabiliser, would cause the stabiliser drive motor to ‘stall’).

BOAC could be confusing the situation by mentioning that “A 'Vertical Stabiliser' sits vertically but controls horizontally”. Actually it doesn’t ‘control’ it simply ensures that the aircraft is kept stable about the vertical axis. The Rudder (or rudder trim) controls the movement of the aircraft about the vertical axis. But maybe we’re getting into ‘semantics’ here.

Having said all that, I won’t even get into ‘all flying tailplanes’, which is in another ball park altogether!

What Mr Davies’ means when he says that pilots should not run the stabiliser very far back before it becomes obvious they have regained pitch control of the aeroplane., I simply don’t know.

I hope I haven’t confused the situation further.

[BOAC]

But maybe we’re getting into ‘semantics’ here - certainly are for a simple question, but I think donnlass has disappeared up his/her own................ so don't worry.

[Lukeafb1]

BOAC,

I realised as I was writing a reply that it was getting a bit confusing! Even started to confuse me!!! :ok:

[donnlass]

I havent disappeared anywhere just havent been able to get back online till today but thanks everyone for your replies.

What I'm trying to get is a picture of what the stabiliser looks like and how it works in the tail.

Is the stabiliser the elevators then and the rudder?

From "Running the stabiliser very far back" I get the impression of something which can be moved backwards and forwards in the tail but that is obviously incorrect even for an SLF lol.

Hope that makes sense and thanks again:)


What is 'Chromo'?

By Chromo I meant the database at MAN that lists all the aircraft due which lets them plan for arrivals and departures and which that Dreamliner would have been listed on had it come to MAN the other week when it was meant to.

Dont know if I have named it correctly:)

[BOAC]

Aha - you are back! Did you read post #2? What did you not follow? I think you need to walk before you run so ignore Mr Davies.

No idea about 'Chromo'. EDIT: Ain't Google wonderful?

CHROMO
A totally and completely useless individual whose sole purpose in life is to stand there and look good. They have the potential to do something useful, but just won't. Chromos generally go to great lengths to avoid responsibility. They are usually very self-centered, incredibly dense, impulsive liars, and are almost always undeniably hot.

Believe it or not, this term comes from the word "chromoplast," an organelle within a plant cell that is created once a chloroplast dies. Chromoplasts, like chromos, are useless. They only provide nice colors for the plant, hence the general hotness of chromos.

CHROMO
Any useless, annoying individual. The word implies low intelligence and social status, and/or lack of moral values.
Only moderately insulting, the term conveys the idea that the person thus designated is looked-down on, but not hated.

I suspect it is the wrong word?

[donnlass]

Aha - you are back! Did you read post #2? What did you not follow? I think you need to walk before you run so ignore Mr Davies.

No idea about 'Chromo'. EDIT: Ain't Google wonderful?

CHROMO
A totally and completely useless individual whose sole purpose in life is to stand there and look good. They have the potential to do something useful, but just won't. Chromos generally go to great lengths to avoid responsibility. They are usually very self-centered, incredibly dense, impulsive liars, and are almost always undeniably hot.

Believe it or not, this term comes from the word "chromoplast," an organelle within a plant cell that is created once a chloroplast dies. Chromoplasts, like chromos, are useless. They only provide nice colors for the plant, hence the general hotness of chromos.

CHROMO
Any useless, annoying individual. The word implies low intelligence and social status, and/or lack of moral values.
Only moderately insulting, the term conveys the idea that the person thus designated is looked-down on, but not hated.

I suspect it is the wrong word?

Hi thanks I will do.

Yes I read your post and it does explain very well all the control surfaces on the tail so maybe I am just trying too involved a question.

Mind you this explains it as well, showing the actual drive motor for the Airbus 340, small picture but shows it clearly.



http://www.goodrich.com/Goodrich/Businesses/Actuation-Systems/Products/Primary-Flight-Controls/Trimmable-Horizontal-Stabilizer-Actuation


Thanks again for both your posts:)

That chromo thing, not sure now. The proper name as I said is in the thread about the 787 coming to manchester but I cant find it anywhere.

If anyone can bring it up again, Id appreciate it.

[Lightning Mate]

...to the tailplane (or vertical stabiliser)

One feels that some clarification is required here.

The vertical stabiliser is the fin, which confers directional static and dynamic stability.

The tailplane is horizontal (discounting dihedral or anhedral), and confers static and dynamic longitudinal stability.

On jet transport aeroplanes the elevators are not trimmed. The variable-incidence tailplane is used for this purpose. This reduces trim drag and confers full elevator authority no matter what the trim point.

One feels that BOAC has added the right tone.

donnlass,

You have now received responses from two ex-RAF flying instructors - you should be honoured!

[Lord Spandex Masher]

LM, don't forget the 146/RJ. It dosn't have a variable incidence jobby but a trimmed elevator.












Standing by for the usual 146 isn't a proper jet banter!

[Lightning Mate]

Agreed, but doesn't the RJ series have manual elevator control?

[Lord Spandex Masher]

It does, with servo and trim tabs and a Q pot for feel.

[Lightning Mate]

Well - there's the answer then.

[AircraftOperations]

By Chromo, do you mean Chroma?

Think that is the inhouse operating system at MAN, available to the airport and handling agents.

I can't imagine it is available to anyone who isn't employed on site.

[donnlass]

One feels that some clarification is required here.
The vertical stabiliser is the fin, which confers directional static and dynamic stability.

The tailplane is horizontal (discounting dihedral or anhedral), and confers static and dynamic longitudinal stability.

On jet transport aeroplanes the elevators are not trimmed. The variable-incidence tailplane is used for this purpose. This reduces trim drag and confers full elevator authority no matter what the trim point.

One feels that BOAC has added the right tone.

donnlass,

You have now received responses from two ex-RAF flying instructors - you should be honoured!

I am and thanks for your answers, they have been very helpful and helped me understand the workings of the stabiliser and tail.

And for Chroma, thanks again, I wasnt too far wrong there lol:ok: