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sedenion

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I know this is an old aircraft, I know there is no FBW, but is that normal I can't even dogfigt a Su-25 ? The plane is incredibely sensitive and unstable, especially in yaw, but also in pitch...  It is almost impossible to keep track on target, at any speed, each stick impulse in pitch or roll creates huge oscilation that shake the aircraft like dead leaf in the wind.

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2 minutes ago, Los said:

Have you adjusted your curves?

Indeed, adjusting curves may help transforming the aircraft in a jumbo-jet by avoiding any excessive (usual) manovers, but de facto, a jumbo-jet cannot dogfight an Su-25...
The problem seem to be that you have to transform the aircraft in a jumbo-jet to fly it in a stable way.

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I happen to have an 25cm (~10 inch) extension in my Warthog, I still have to use curves in every module to mimic a comfortable response in pitch and roll, not too sensitive and all despite the extension which already gives you way more control and precision than short vanilla stick. By the way, I haven't used any curve in F1 so far, point being, it's not so sensitive at all compared to 99% of the other modules. Try using curves, they are there to be used, and your aircraft won't become any Jumbo, you'll just be able to control it as it's meant to be since we usually don't have real controls (long sticks to start with) available at home to fully represent a real aircraft's controls behaviour, but curves do just fine to match that having a short stick.

"I went into the British Army believing that if you want peace you must prepare for war. I believe now that if you prepare for war, you get war."

-- Major-General Frederick B. Maurice

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Maybe this is because I'm pretty used to flying the Mig-21, but the Mirage F1 feels extremely stable & easy to fly in comparison. I have a VKB Gunfighter Mk.III (placed on my desk, no extensions) & have my pitch/roll axes curves set to '20'

The Mirage, just like the Mig-21 does seem to have a tendency to just drop out of the sky if you bleed too much speed ; worth noting, both of those plane will need proper rudder input to guarantee coordinated flight, or you will get a fair bit of adverse yaw.

 


Edited by Althar93
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6 minutes ago, Ala13_ManOWar said:

I happen to have an 25cm (~10 inch) extension in my Warthog, I still have to use curves in every module to mimic a comfortable response in pitch and roll, not too sensitive and all despite the extension which already gives you way more control and precision than short vanilla stick. By the way, I haven't used any curve in F1 so far, point being, it's not so sensitive at all compared to 99% of the other modules. Try using curves, they are there to be used, and your aircraft won't become any Jumbo, you'll just be able to control it as it's meant to be since we usually don't have real controls (long sticks to start with) available at home to fully represent a real aircraft's controls behaviour, but curves do just fine to match that having a short stick.

Using my MS FFB2 and it's very twitchy, but that's kinda expected with that short stick. And curves don't play nice with FFB, so that's not an option. Will try with my 40cm Warthog now though. 😊 

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I'm running a Warthog on a 20cm extension and have a much different experience than Ala13. I usually need 0 curves on any module--helos and warbirds included--but the F1 is indeed very unstable in pitch and yaw. Between 350 and 400kts there are major yaw oscillations when making quick banks. Roll seems normal to me.

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2 hours ago, sedenion said:

I know this is an old aircraft, I know there is no FBW, but is that normal I can't even dogfigt a Su-25 ? The plane is incredibely sensitive and unstable, especially in yaw, but also in pitch...  It is almost impossible to keep track on target, at any speed, each stick impulse in pitch or roll creates huge oscilation that shake the aircraft like dead leaf in the wind.

As soon as you build up AoA, you need to use rudder to roll and make coordinated turns.
With that in mind, it's a very stable aircraft, much more easy than MiG-21.

AI Su-25 (like many IA) has kind of an UFO flight model.

Tips: use 2 circles combat tactics, best turning speed is 300kt/ 17° AoA.
If below 300kt/ M0,75 use combat flat.
Speed is very easy to control during the turn.

Just take care to not over-G too much at high speed 😅
And since it doesn't bleed much energy during a turn, it's easy to overshoot.
With stores/ fuel tanks it isn't really fast to accelerate, once you drop, with Fox 2 on wing rails it's OK.

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Mirage fanatic !

I7-7700K/ MSI RTX3080/ RAM 64 Go/ SSD / TM Hornet stick-Virpil WarBRD + Virpil CM3 Throttle + MFG Crosswind + Reverb G2.

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1 hour ago, jojo said:

As soon as you build up AoA, you need to use rudder to roll and make coordinated turns.
With that in mind, it's a very stable aircraft, much more easy than MiG-21.

AI Su-25 (like many IA) has kind of an UFO flight model.

Tips: use 2 circles combat tactics, best turning speed is 300kt/ 17° AoA.
If below 300kt/ M0,75 use combat flat.
Speed is very easy to control during the turn.

Just take care to not over-G too much at high speed 😅
And since it doesn't bleed much energy during a turn, it's easy to overshoot.
With stores/ fuel tanks it isn't really fast to accelerate, once you drop, with Fox 2 on wing rails it's OK.

Tuned axes, made my best... I give up for now: I tryed guns-only against AI Su-25 and AI Mig-21BIS, I am almost unable to get fire oportunity against Su-25 and got hit by the Mig-21 after few turns. I am probably not well trained, but to me the Mirage F1, as it is, in addition with the lack of proper gun sighting system, is unable to dogfight.

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9 minutes ago, sedenion said:

the Mirage F1, as it is, in addition with the lack of proper gun sighting system, is unable to dogfight.

Well, it was designed and built in the 60s-70s, so a lot of its systems, 'HUD' included, are fairly primitive still & the plane won't hold your hand. The challenge is certainly where the fun is at for me.

I wouldn't expect it to get any 'better' either, AFAIK, this is just how the plane flew/fought.


Edited by Althar93
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Dropping the MS FFB2 and using my Warthog with 40cm helped tremendously, as expected. Been flying helis a lot lately.

Got my first MiG-21 with missiles. I have yet to find anything with the radar, but air to ground is fairly easy now too. 

Loving this module! Thanks a bunch Aerges! 

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5 hours ago, Althar93 said:

Well, it was designed and built in the 60s-70s, so a lot of its systems, 'HUD' included, are fairly primitive still & the plane won't hold your hand. The challenge is certainly where the fun is at for me.

I wouldn't expect it to get any 'better' either, AFAIK, this is just how the plane flew/fought.

 

From what I could gather, even French Air Force Mirage F1C in 1974 had gun telemetry. So that's probably missing due to early access and not a lack of the orignal fighter.

But it can be difficult to asses because options would change greatly between export customers.

AI F-4 Phantom should be a good start for training.😇


Edited by jojo
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Mirage fanatic !

I7-7700K/ MSI RTX3080/ RAM 64 Go/ SSD / TM Hornet stick-Virpil WarBRD + Virpil CM3 Throttle + MFG Crosswind + Reverb G2.

Flickr gallery: https://www.flickr.com/gp/71068385@N02/728Hbi

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10 hours ago, sedenion said:

I know this is an old aircraft, I know there is no FBW, but is that normal I can't even dogfigt a Su-25 ? The plane is incredibely sensitive and unstable, especially in yaw, but also in pitch...  It is almost impossible to keep track on target, at any speed, each stick impulse in pitch or roll creates huge oscilation that shake the aircraft like dead leaf in the wind.

 

You need to use the rudder when you make a roll input and keep the ball centered (the slideslip indicator on the bottom of the main artificial horizon)

At higher AoA more rudder is needed!

At very high AoA use the rudder only if you want to roll.

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6 hours ago, HWasp said:

You need to use the rudder when you make a roll input and keep the ball centered (the slideslip indicator on the bottom of the main artificial horizon)

At higher AoA more rudder is needed!

At very high AoA use the rudder only if you want to roll.

This is the part of the flight model I question, and I asked in another thread but got no response. Rudder at high AoA is common among all jets pre-FBW, however rudder at low AoA shouldn't be necessary due to differential ailerons, yaw dampers, etc. Yet, in the F1 it is. I'm confused why the F1's low-AoA flight characteristics are so wildly different than the low-AoA characteristics of the F-86, MiG-15, MiG-19, MiG-21, F-5, L-39, and F-14. It's as if the F1's yaw damper switch isn't functioning. 


Edited by Nealius
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10 hours ago, HWasp said:

 

You need to use the rudder when you make a roll input and keep the ball centered (the slideslip indicator on the bottom of the main artificial horizon)

At higher AoA more rudder is needed!

At very high AoA use the rudder only if you want to roll.

I don't have real rudder device, I use warthog throttle mini-stick as ersatz, which is sufficient for my usual usage (taxiing, mainly).

I tend to think like Nealius stated in the post above, there is currently a lack of automated controls assistances. Mirage F1 is not a modern aircraft, but it is definitely more modern than Mig-21 for example (and with a more classical wing configuration) and it comes right before its well known sucessor, the Mirage 2000, which is full FBW.  And as we can read in the current manual, there is actually (theoretically) plenty of automated controls assistances, as non-exhaustive example:

  • Pitch mode switch: allows to activate and deactivate the pitch electrohydraulic mode.
  • Yaw mode switch Anti-slip/Yaw/Off: allows to deactivate the anti-slip mode and the electrohydraulic mode separately.
  • ARTHUR switch (under guard) AUTO/HIGH/LOW: Allows the pilot to select the sensitivity mode of the ARTHUR

To what you must add the Combat Flaps mode, which indicate that the aircraft was not only designed for ground attack or air-air missiles (unlike the F-4 Phantom for example)...

I don't know how much these controls assistance systems are currently implemented in the module, but my guess is that they need adjustements.
As everybody noticed, the aircraft is currently almost uncontrolable in pitch unless you crop 30-40% saturation of the axis response curve ... which is HUGE, and probably NOT normal. And at this precise subject, even without simulated control assistance, we can guess that the real controls stick have progressive resistance, requiring high strenght to pull out the stick as its maximum amplitude, in order to avoid ludicrous manoeuvers... and this should be also implemented as a response curve within the module, since our toys are unable to reproduce that.


Edited by sedenion
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24 minutes ago, sedenion said:

I don't have real rudder device, I use warthog throttle mini-stick as ersatz, which is sufficient for my usual usage (taxiing, mainly).

I tend to think like Nealius stated in the post above, there is currently a lack of automated controls assistances. Mirage F1 is not a modern aircraft, but it is definitely more modern than Mig-21 for example (and with a more classical wing configuration) and it comes right before its well known sucessor, the Mirage 2000, which is full FBW.  And as we can read in the current manual, there is actually (theoretically) plenty of automated controls assistances, as non-exhaustive example:

  • Pitch mode switch: allows to activate and deactivate the pitch electrohydraulic mode.
  • Yaw mode switch Anti-slip/Yaw/Off: allows to deactivate the anti-slip mode and the electrohydraulic mode separately.
  • ARTHUR switch (under guard) AUTO/HIGH/LOW: Allows the pilot to select the sensitivity mode of the ARTHUR

To what you must add the Combat Flaps mode, which indicate that the aircraft was not only designed for ground attack or air-air missiles (unlike the F-4 Phantom for example)...

I don't know how much these controls assistance systems are currently implemented in the module, but my guess is that they need adjustements.
As everybody noticed, the aircraft is currently almost uncontrolable in pitch unless you crop 30-40% saturation of the axis response curve ... which is HUGE, and probably NOT normal. And at this precise subject, even without simulated control assistance, we can guess that the real controls stick have progressive resistance, requiring high strenght to pull out the stick as its maximum amplitude, in order to avoid ludicrous manoeuvers... and this should be also implemented as a response curve within the module, since our toys are unable to reproduce that.

 

Everybody noticed? I fly it with a simple joystick, no extensions, no curves, no problem... Don't come up with claims like that, it is not uncontrollable in any way. 

I don't have a real rudder as well, only a twist axis on the stick. That is a real control axis though. 

If you are using some non-standard workarounds to control rudder axis, then you should not blame the module for being difficult to control. It's a basic aircraft control, it needs a proper control axis.

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7 hours ago, Nealius said:

This is the part of the flight model I question, and I asked in another thread but got no response. Rudder at high AoA is common among all jets pre-FBW, however rudder at low AoA shouldn't be necessary due to differential ailerons, yaw dampers, etc. Yet, in the F1 it is. I'm confused why the F1's low-AoA flight characteristics are so wildly different than the low-AoA characteristics of the F-86, MiG-15, MiG-19, MiG-21, F-5, L-39, and F-14. It's as if the F1's yaw damper switch isn't functioning. 

 

I checked what happens during a roll with time slowed down to 1/4, there are certainly rudder movements commanded by the yaw damper, so it is trying to do it's thing, but seems to have limited authority.

For me, at low AoA, as long as I use less than half aileron (already 90deg/sec+ I think), slideslip is not a big issue. It really is quite different to the others, but I wouldn't jump to any conclusions just because of that.

Switched off the damper, and there is a difference for sure, so the system is doing it's thing.

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3 minutes ago, HWasp said:

Everybody noticed? I fly it with a simple joystick, no extensions, no curves, no problem... Don't come up with claims like that, it is not uncontrollable in any way.

Ok, sorry for the peremtoire sentence, but be honest, the pitch sensitivity is too high. Yes, you can deal with the native response curve by moving the stick in a extremely gentle way but even for normal manoeuvers, you go above the red very quickly. So, in dogfight, where you try extreme manoeuvers by definition, you clearly need a saturation croped response curve, unless you want to train for rodeo contest...

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2 hours ago, HWasp said:

If you are using some non-standard workarounds to control rudder axis, then you should not blame the module for being difficult to control. It's a basic aircraft control, it needs a proper control axis.

I don't blame anything... I simply tell what it is. Currently what I found after some reasarch, is that the real Mirage F1 actually HAS yaw damping systems, and one in particular named "ARTHUR" [EDIT: in fact it seem to be a kind of "power steering" but applied to stick moves], which, I am pretty sure is currently not implemented in the module... I also guess (this is a guess) that the current Pitch electrohydrolic mechanism is either not implemented, or need adjustements. It is also mentionned a pitch auto-trim...

Here is what I found in french forum about Mirage F1 controls (which seem a not exhaustive listing) :

https://www.checksix-forums.com/viewtopic.php?p=1832909&sid=647aa22917dff2eecb3d0c4f0b657826#p1832909
Translation:

Quote

To make it short (from memory):

- ARTHUR: is to increase the efforts on the stick according to the MACH ("small ARTHUR" = small efforts / "big ARTHUR" = big efforts). Hydraulic cylinder.

- AMÉDÉE: is to increase precision around neutral. Purely mechanical system.

- DASHPOT: it is to limit a speed of movement of the stick according to the IAS. A kind of hydraulic shock absorber.

- SRA: This is to provide artificial effort restitution, with greater effort towards extreme debates. I'll spare you the details on the pre-servo elevator which "blocked" the AP stick (the AP orders being sent electrically to it, the stick followed its movement), the triple sensor (on the SRA) with the horn declutchable which allows "electric" piloting (therefore stick separated from the depth servo-controls, these being controlled according to electrical orders produced by the AP rack according to the position information of the triple sensor + the depth damping orders and warping).

The F1 flight controls were goldsmithery, great art...


Edited by sedenion
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I thought ARTHUR just affects pitch control by limiting it at high speeds (similar to MiG-21s ARU system), but there definitely are yaw dampener, and it seems ineffective since it doesn't compensate even for slow rolls at low AoA. I am not a pilot, but roll-associated yaw at low AoA does seem kinda excessive with minimal aileron deflection, with high roll inputs it feels right since there are spoilers above the wing that deploy at high lateral stick deflections. And fore me F1 seems pretty stable overall, I use WarBRD base (no extensions) with no curves and it controls a lot smoother than MiG-21, without pitch oscillations (well, unless you yank the stick hard). Did you use combat flaps in dogfight?

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12 minutes ago, Aernov said:

I thought ARTHUR just affects pitch control by limiting it at high speeds (similar to MiG-21s ARU system)

Nop. See above... Mirage F1 also have such limiter, but it is not ARTHUR...

14 minutes ago, Aernov said:

Did you use combat flaps in dogfight?

I tried with and without, I did not noticed big difference since below 300 kts (which seem pretty high speed to me, but maybe I am wrong) the aircraft become very hard to manoeuver.

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Aerges has mentioned something regarding stick sensitivity in the last page (130) of the manual A nd the use of rudders is mandatory at slow speed  high aoa to roll the ac. Much more stable and forgiving than the  F-14. Curvature 20 for me does the job for both modules


Edited by jaguara5
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47 minutes ago, jaguara5 said:

the use of rudders is mandatory at slow speed  high aoa to roll the ac.

This part of the manual explain the risk of spin by rolling unreasonable way at low speed / High AOA... which is true for almost all aircrafts... in the same logic : beware, at very very low speed, the flight controls are not responding anymore and aircraft begins to fall like a stone...

The main problem here is : what exactly is "low speed", and "high AOA". "low speed" and "high AOA" is not the same for a Cesna 172 and a F-16... So, at which speed it become impossible to properly stabilize the aircraft roll and yaw without constantly playing with our feets ? It is absolutely normal to have a very careful manoeuvring at landing, but, landing is a very specific situation.

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