M2K, FBW and trim question

[Pikey]

I have a question on the FBW implementation of the Mirage. I understand most of my FBW experience from the F-16 model in BMS so forgive any misunderstandings. So, to an extent, the flight control auto trims in Fly by Wire, but the is still a coarse trim adjustment for zeroing out any asymetry.

 

Under what circumstances does a pilot use the trims in M2K?

 

How firmly can the FCS hold the pitch and roll and yaw each before eventually allowing it to ... pitch roll or yaw?

 

If say the pitch is zero'd and you apply 1g of pitch up with the trim, will the plane continue in a 1g pitch up forever or will the pitch be measured with something that is not measured in G force?

 

Thanks to anyone that knows.

[Corsair]

Trim is most generally used coupled with autopilot. The trim then acts as cue for the autopilot.

 

FBW autotrim laws of the 2000 are not G-driven like on the F-16 but attitude-driven (maintains a constant attitude).

Edited December 11, 2015 by Corsair

[Pikey]

Thanks for the response, I think i'm really stupid about this though, is the trim then more like a traditional trim where if you add power the plane begins to pitch up and you trim down to neutralise it? In which case doesn't sound much like a fly by wire? But i'm probably adding too much to what FBW really is then...

[Corsair]

Well, to me, there are two cases :

 

- Autopilot off, the trim basically works like a standard trim. However, I am not sure if loadout asymmetry is compensated automatically.

 

- Autopilot on, in basic mode, which holds your attitude (bank and pitch). The trim then acts like a mini stick, to send precise inputs to the autopilot. A click left, the autopilot banks a little (but keeps this position, and does not continue to roll) and so on. If the pilot needs to perform an important trajectory correction, he depresses a palet behind the stick, which temporarily disconnects the autopilot. After the correction is made, he releases it, and the autopilot keeps the new attitude, modifiable via the trim inputs.

 

This is how I see it. However, it could need confirmation (especially on the asymmetry thing).

[cmbaviator]

M2K, FBW and trim question

 

Okay guys.

 

FBW Means that there is no mechanical link between side stick and surfaces control.

 

For example the embraer e175 family has FBW but you have to trim like a Cessna or B737.

 

But FBW can allow some better flying characteristic when hand flying => C* law: the aircraft is flight path stable , meaning it will TRY to maintain the current path even with speed, config and roll change when the stick is at neutral: implemented in the A320 or C*U speed stable meaning that it will try to maintain the trimmed speed= B777.

 

I don't know much about military plane with FBW but what I'm trying to mean is that FBW doesn't = all the time to autotrim

 

 

CMB

 

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[Pikey]

Exactly, which is why I ask, what form the FBW is going to take, what it can and cannot do and how trim works in conjunction with it etc. I'm still not sure what's authoratitive in the post as I only have your usernames, I do not know your credentials as to the operation of the Mirage 2000C. Thanks.

 

Okay guys.

 

FBW Means that there is no mechanical link between side stick and surfaces control.

 

For example the embraer e175 family has FBW but you have to trim like a Cessna or B737.

 

But FBW can allow some better flying characteristic when hand flying => C* law: the aircraft is flight path stable , meaning it will TRY to maintain the current path even with speed, config and roll change when the stick is at neutral: implemented in the A320 or C*U speed stable meaning that it will try to maintain the trimmed speed= B777.

 

I don't know much about military plane with FBW but what I'm trying to mean is that FBW doesn't = all the time to autotrim

 

 

CMB

 

Sent from Tapatalk

[Arden]

So the main question now is, can we "just trim it out"?

[Azrayen]

I am also glad you mentioned the trim switch that temp disconnect the AP, I had that on my list to complete and higher priorities took over, so I will make sure to implement that.

 

[...]

 

EDIT: Was in the middle of working on some other FCS related stuff, most of the stub code was there for the AP overide/standby HOTAS switch, so I went ahead and just added it in :) Thanks for the reminder Corsair

Great news, that is definitely a major function needed for flying the M2000 as in real life :thumbup:

 

This "palet" should be a button to map on the joystick, right? Not sure if it should be press-and-hold (as in the real aircraft) or toggle (because we don't have the real stick). I guess offering both options will be the best, if possible.

 

I guess the low trigger of the Warthog (or the NWS button) will be perfect choices for mapping this.

[bzhnono]

Great news, that is definitely a major function needed for flying the M2000 as in real life :thumbup:

 

This "palet" should be a button to map on the joystick, right? Not sure if it should be press-and-hold (as in the real aircraft) or toggle (because we don't have the real stick). I guess offering both options will be the best, if possible.

 

I guess the low trigger of the Warthog (or the NWS button) will be perfect choices for mapping this.

the palet and the NWS are still used for brakin and NWS for me... too bad (I don't own rudder pedals with my X55).

[jojo]

A lot of HOTAS have a kind of pinkie switch that can be assigned to this feature.

[Corsair]

Both COugar and Warthog are equipped of this paddle switch (palet was a rough frenglish translation :D)

[jojo]

Saitek X-55 too :D