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Mirage 2000-5

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Re: Mirage 2000-5

Postby F5SLQ » Thu May 28, 2020 7:43 am

Hi all,
I confirm that the 2 seats is working perfectly.
Tnx 5H1N0B1
Best regards.
NVIDIA GeForce RTX 3070Ti - 8GB / i9-12900 KF CPU @ 5.0 GHz / RAM : 32 Go à 3,2GHz - Joystick Logitech Extreme 3D PRO
Multi player callsign : F-JEEP
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Re: Mirage 2000-5

Postby openflight » Sun Jun 14, 2020 3:02 am

I just flew the Mirage2000-5 in my machine if you could call it that: No time for a full review but:

Plus points - lovely model, great features, nice flight model as far as my stuttering machine would reveal, with excellent stall behaviour at about 120 kt and 20 degrees AoA, like the real thing.

Big Minus Point: Elevon travel is much too large in the 3D model, I have never seen the elevons move noticeably in the real thing except in rolls, and slightly before take off (maybe 20 degrees) never in flight. This is a huge mistake in many FG models.

I am updating the old Mirage 2007 version here:

viewtopic.php?f=4&t=37523&start=30

Here are my Machine Details and FG Version:

FlightGear: Version 2018.1.1

There were frame rate related problems running the Mirage 2000-5 even in this version even with all the graphics turned off, it is still laggy with frame rates less than 10 for sure. This is the exact reason that I stick with the older Flight Gear versions, and hence older planes .. for now..

Celeron CPU - 4GB RAM - 2015 Model, Integrated Graphics

Details:

*-cpu
product: Intel(R) Celeron(R) CPU N3050 @ 1.60GHz
vendor: Intel Corp.
physical id: 1
bus info: cpu@0
size: 1454MHz
capacity: 2160MHz
width: 64 bits

*-display
description: VGA compatible controller
product: Atom/Celeron/Pentium Processor x5-E8000/J3xxx/N3xxx Integrated Graphics Controller
vendor: Intel Corporation
Last edited by openflight on Mon Jun 15, 2020 1:44 am, edited 1 time in total.
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Re: Mirage 2000-5

Postby Octal450 » Sun Jun 14, 2020 3:05 pm

Actually the flight model is pretty bad, which is expected since its YASIM. I've tried to hide as much of it as I could in the FBW but....

Kind Regards,
Josh
Skillset: JSBsim Flight Dynamics, Systems, Canvas, Autoflight/Control, Instrumentation, Animations
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Re: Mirage 2000-5

Postby openflight » Mon Jun 15, 2020 1:54 am

I am not using a joystick after all. It seems accurate enough. An in - cockpit joystick would also help to gauge where the controls are.

BTW how do you implement FBW in YASIM or any other simulator? Do you make the model unstable and then write code to make it stable - which does not seem to make sense to me - or do you fine tune the response rates, pitch response in particular, and G- onset, which looks very sharp from the videos I see.

All flying must be done with at least a little turbulence to be realistic - you see formation videos of the real thing - cockpit view - they are all bouncing around.
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Re: Mirage 2000-5

Postby Octal450 » Mon Jun 15, 2020 6:54 pm

YAsim is garbo.

So I faked a dynamically unstable airplane by using magic on the elevator trim.

FlyByWire is electric signals to hydraulic or servo instead of cable to hydraulic control. But mostly they all have a feedback control loop which is what actually flies the plane. In the mirage, I used CSTAR, Roll Rate, and Beta.

Kind Regards,
Josh
Skillset: JSBsim Flight Dynamics, Systems, Canvas, Autoflight/Control, Instrumentation, Animations
Aircraft: A320-family, MD-11, MD-80, Contribs in a few others

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Re: Mirage 2000-5

Postby openflight » Tue Jun 16, 2020 3:54 am

So I faked a dynamically unstable airplane by using magic on the elevator trim.


Not sure what you mean, if you have the time to elaborate: here is the xml from the conf file in /systems

m2000-5-yasim.xml

Code: Select all
<hstab x="-5" y="0.5" z="-0.933"
         chord="1"
         length="4"
         taper="1"
         sweep="0"
         camber="0.07"
         dihedral="-4">
    <stall aoa="29" width="4" peak="1.5" />
    <flap0 start="0.1" end="0.90" lift="1.68" drag="1.35" />
    <spoiler start="0"  end="0.9" lift="0" drag="200" />

    <control-input axis="/it-fbw/output/pitch" control="FLAP0" />
    <control-input axis="/controls/flight/elevator-trim" control="FLAP0" />
    <control-input axis="/sim/model/door-positions/parachute/position-norm" control="SPOILER" />

    <control-output control="FLAP0" prop="/surface-positions/elevator-pos-norm" />
    <control-speed  control="FLAP0" transition-time="0.08" />

  </hstab>
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Re: Mirage 2000-5

Postby Octal450 » Tue Jun 16, 2020 5:28 am

Hi Openflight
Nope, nothing to do with that. I just scheduled elevator trim in a way the plane behaves somewhat like a dynamically unstable plane. As the trim is not used in the FlyByWire (and stupid yasim won't let me use a custom prop) for trim. Then for the FlyByWire control system, I suggest to do some studying on control theory and control engineering to see what I mean.

Kind Regards,
Josh
Skillset: JSBsim Flight Dynamics, Systems, Canvas, Autoflight/Control, Instrumentation, Animations
Aircraft: A320-family, MD-11, MD-80, Contribs in a few others

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Re: Mirage 2000-5

Postby openflight » Wed Jun 17, 2020 1:43 am

Ok Thanks Josh.
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Re: Mirage 2000-5

Postby openflight » Sat Jun 20, 2020 2:27 am

There is an article on FBW for airliners and other aircraft on FG. Not sure of JBSIM or YASIM compatible.

http://wiki.flightgear.org/Howto:Implem ... _Airliners
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Re: Mirage 2000-5

Postby 5H1N0B1 » Sat Jun 20, 2020 8:50 am

I'm not sure to understand what you are trying to do...
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Re: Mirage 2000-5

Postby Octal450 » Sat Jun 20, 2020 1:51 pm

Hi openflight,
I'm not sure if you understand the goal of REALISM here...

That article, is a bullshit thing. It is basically saying "oh look lets just slap in a pid on this and some weird math/logic and that will work" - well it doesn't. That's why when I got my hands onto the Airbus, I rewrote everything, and the 787 needs the same. You can't just throw PIDs at stuff blindly and say "hey look a FBW".

I already made a pretty realistic FBW for this plane, and the more realistic JSBsim version has a more advanced version of my FBW. There is no need to even consider that wiki article whatsoever.

Kind Regards,
Josh
Skillset: JSBsim Flight Dynamics, Systems, Canvas, Autoflight/Control, Instrumentation, Animations
Aircraft: A320-family, MD-11, MD-80, Contribs in a few others

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Re: Mirage 2000-5

Postby openflight » Sat Jun 20, 2020 3:30 pm

I had no idea that article was lets say 'unhelpful'.

How do we know we have arrived at a realistic FDM when we get there? Pilot reports, videos, impressions? In case I decide to, and I have been adjusting the flight model of the Mirage 2000, it seems to have little roll inertia, and the suggestion is to add drop tanks, but anything else?
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Re: Mirage 2000-5

Postby Octal450 » Sat Jun 20, 2020 3:40 pm

Well the current YAsim is garbo - but that is expected from YAsim. I've yet to fly a single YAsim that flies without significant flaws especially in the pitch and yaw axis.

the JSBsim is much better.

Kind Regards,
Josh
Skillset: JSBsim Flight Dynamics, Systems, Canvas, Autoflight/Control, Instrumentation, Animations
Aircraft: A320-family, MD-11, MD-80, Contribs in a few others

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Re: Mirage 2000-5

Postby Octal450 » Sun Jun 21, 2020 5:01 pm

Hi,
I just pushed some improvements to the JSBsim FlyByWire and Richard merged his new AMAZING FDM into master. Feedback would be greatly appreciate.

Kind Regards,
Josh
Skillset: JSBsim Flight Dynamics, Systems, Canvas, Autoflight/Control, Instrumentation, Animations
Aircraft: A320-family, MD-11, MD-80, Contribs in a few others

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Re: Mirage 2000-5

Postby openflight » Mon Jun 22, 2020 1:23 am

This is for the Mirage 2000-5 model?
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