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AF330

Trim Angle

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Hi

For example, if we say that it won't trim above 14 degree angle, what does it mean? Is the trim angle the pitch angle, but with a THS? What is trim angle? And between which line is it? (horizon, velocity, where the aircraft is pointing...)

 

Thanks

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Take the time to learn how an aircraft flys and what it's controls do. I've read all of your posts where you're trying to get everyone to teach you all about the Airbus... but you actually just don't understand the very basics of an aircraft and it's systems.

 

A limited knowleged of the fly-by-wire computer interface matters little without understanding the very basics of what the aircraft systems themselves do.

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I'm not trying to be rude/mean... but... try Google.

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Take the time to learn about the basics of flying, the basics of navigating, principles of flight...

I imagine Angle of Attack's Aviator90 course would be a good start.

You're trying to run, but you don't even know how to crawl yet.

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I have tried google. I am not sure but I think it's pitch, because when I typed it, I saw pitch angle stuff... Am I right?

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Hi.

 

 

Thanks
Where coild I find my answer?

 

 

Trimming just takes the strain out of your arms and legs but there's only so much that the mechanical stuff will do for you. After that, you (and your limbs) are on your own... though it could be argued that you shouldn't be doing such things with a plane.

 

Read through this:

 

http://x-plane.deinon.com/aircraft_trim.pdf

 

I think you'd benefit very much from taking a trip out to your local airfield (a club rather than a commercial airport) and asking the receptionist if someone can show you controls and control surfaces on a couple of light aircraft and to explain how they work.

 

Even if your simming preference is for heavy jets, there's no real substitute for seeing stuff in the flesh.

 

Cheers,

D

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Learn about aircraft... really.

 

Trim is where it adjusts the physical control surface either directly or indirectly so that it maintains a given amount of control input.

 

The trim angle is usually referring to elevator trim but it can also mean rudder and aileron trim. Like I've said... go learn about aircraft in general... you're seriously not ready for anything more complex than an Cessna 172 at this point.

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Thanks, trim angle is based on pitch angle ;)

 

Actually, no it isn't. 

 

Somehow, I don't think this is how Mohammed Atta did it.

 

Maybe if you tell us where the questions are coming from so we can get some context as to what you are asking.  There's probably a quick way to learn everything you need to know, but you aren't going to find out what it is by asking individual questions like this. 

 

Hook

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Coming from me! Just learnt FPA/PITCH ANGLE and AoA... So thought about this.

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Maybe if you tell us where the questions are coming from

 

I am starting to think he has been selected as a P2F direct entry first officer with a low cost carrier ;)  

 

 Requirements are - Zero flying experience,   25  years or younger,  teach yourself how an A320 works!

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You were 14 last time.  :)

 

I think Rob's right.  It's obvious we're doing your homework, I'm just wondering what your homework is.  You can't possibly be making these questions up.  You have to be getting them somewhere.  So... where are the questions coming from?  We can answer better if we know.

 

And I still don't think you've got the answer to your original question.  I know what the answer is, but I'll need some answers from you first, please.

 

Hook

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Going to be 14. 13 now (born november 2000)

Please ask the questions! I read the FBW system and the different angles (bank, fpa, pitch...) and read the THS. So the question came to me....

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Going to be 14. 13 now (born november 2000)

Please ask the questions! I read the FBW system and the different angles (bank, fpa, pitch...) and read the THS. So the question came to me....

 

Just out of curiosity, what do you want to be when you are older?  A pilot? an engineer?  

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An A330 pilot! My dream! ;)

 

Could anyone give me an answer please?

 

Thanks

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Ok, so you're reading about a fly by wire system, probably on the A330.  They mention that the trim is limited to a 14 degree angle.  I don't know anything about that specific plane, but I understand the question. 

 

The elevator trim (the elevator makes the nose of the plane go up and down, the trim function of the elevator helps hold it in a specific position without the pilot holding a control) can be set to cause the nose of the plane to go up to a 14 degree "angle of attack", but no farther, as this would cause the plane to stall.  The angle of attack is the angle between the oncoming wind and the angle of the wing.  Somewhere above that 14 degree limit the wing will stall, which means it will no longer provide lift.  Normally you don't want to go there.

 

Does it say if the trim will be reduced automatically if it causes the angle of attack to be more than 14 degrees?

 

Hook

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If youare very serious about this I very seriously recommend reading this

 

http://www.faa.gov/regulations_policies/handbooks_manuals/aviation/pilot_handbook/

 

And for more details

 

http://www.av8n.com/how/

 

And relevant sections from this

 

https://www.faa.gov/air_traffic/publications/atpubs/aim/index.htm

 

This should give you a more than solid understanding of the basics.

 

I have been looking at all these parts and reluctant to answer the ones I understand simply because you are trying to do gymnastics before learning to crawl.

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Thanks a lot,

The A330 is limited to 30 degrees pitch up and 17 degrees pitch down. So we can imagine that around 16-17 degrees of AoA, the plane has reached alpha max and it can't go further. The 14 degrees AoA (13.5 exactely) is equal to alpha protection. At that moment positive trim will stop.

 

1) What do you think?

2) Does anyone know how much 13,5 AoA is in pitch angle? It should turn around 25-26 degrees...

 

Thanks a lot!

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Again you really need to read the basics because then you would never ask what the relationship between pitch angle and AoA is. It just doesn't make sense and it cannot be answered.

 

An aircraft can be at 0 pitch and cruising with a slight AoA. On the other hand it could be at 0 pitch with an AoA of 50+ degrees on one wing and greater than 90 on the other. This would be found in a spin.

 

The airplane could also be at a -90 pitch angle and at a 0 AoA in a vertical dive.

 

This is not meant to hurt your enthusiasm, that's great, but you should be able to go through the above material very quickly.

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1) What do you think?
2) Does anyone know how much 13,5 AoA is in pitch angle? It should turn around 25-26 degrees...

 

So you have no idea what trim is yet you understand Alpha Max & Alpha Prot??

 

This all sounds like you are cutting and pasting info of the web.. you have been given links and very good advice on getting to grips with the basics, I would suggest you take that advice.

 

If you do really want to study the A330 I would suggest reading FCOM VOL1, all your answers can be found in that document written by the people who designed the aircraft.

 

Here is a reference - FCOM 1.22.30  

 

Alpha FLOOR is activated through autothrust system when :
• Alpha is greater than a threshold depending on the aircraft configuration, the ground speed variation, and the difference between ground speed and air speed or,
• Sidestick deflection is above 14 deg and: 
— pitch altitude is greater than 25 deg, 
or AOA protection is active

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"The airplane could also be at a -90 pitch angle and at a 0 AoA in a vertical dive."

 

Depends of RAF, I imagine...

Alpha prot comes at a certain angle, depending of many factors.

Yes, you can't predict it, sorry made a mistake. And yes Flex, pitch angle should be around 25 degrees, as you can't go how higer than 30 degrees for the A330- 33 degrees for the 320.

If you don't have AoA protection, you are not in normal law.

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Alpha FLOOR is activated through autothrust system when :
• Alpha is greater than a threshold depending on the aircraft configuration, the ground speed variation, and the difference between ground speed and air speed or,
• Sidestick deflection is above 14 deg and:
— pitch altitude is greater than 25 deg,
or AOA protection is active

 

Holy cow!  No wonder he's asking questions.

 

What does "ground speed variation" mean in that sentence?  What is "pitch altitude" and why is any altitude (other than Right Ascension which isn't really an altitude) measured in degrees?  If I were given the above to write a computer algorithm on, I'd be camped on someone's desk and not real gracious about it.  Find me a domain expert who can speak English, dammit!

 

Hook

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Holy cow!  No wonder he's asking questions.

 

What does "ground speed variation" mean in that sentence?  What is "pitch altitude" and why is any altitude (other than Right Ascension which isn't really an altitude) measured in degrees?  If I were given the above to write a computer algorithm on, I'd be camped on someone's desk and not real gracious about it.  Find me a domain expert who can speak English, dammit!

 

Hook

 

 

What does "ground speed variation" mean in that sentence?  What is "pitch altitude"

 

It should read 'Pitch Attitude'... Not sure what happened there..   Alpha floor is an Auto-thrust function,  it also has to make predictions using the FAC's based on the information it is fed. As explained above, variations in ground speed along with calculated differences between airspeed and ground speed is used to calculate when Alpha floor becomes active.

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