A-10 stall behaviour in DCS is incorrect

[cichlidfan]

A-10C uses absolutely the same model as A. Or, sorry, I am wrong: 10A uses the same as 10C...

 

Then why does the A-10A have an AFM+ FM while the A-10C has a PFM. That does not sound like the same model to me.

 

From the Product Terms post.

 

AFM+ and this uses the same calculations as AFM but adds limited modeling of the hydraulic and fuel systems. Examples of AFM+ in DCS include the Su-25 and A-10A.

 

DCS examples of the PFM include the A-10C, ...

 

https://forums.eagle.ru/showthread.php?t=122801

[SCU]

Thanks YoYo, appreciate your effort. There is significant uncommanded roll towards the end of the video at about 11900 ft., which is pretty much what I'm talking about, do yuo think that's working as intended?

[SCU]

No doubt that it is possible to maintain the chopped tone for a bit, I mentioned that more than once, but the thing is, it isn't possible in all conditions which as far as real life evidence suggests it should be possible in all or most conditions, only certain conditions, like a large yaw angle, should induce uncommanded rolls but not pitching or pulling the stick backwards, even while in a roll.

[Yo-Yo]

Although the sim is amazing, it's not perfect. We still have hydraulics with an only windmilling engine, even though the 1A-10A-1 and the real checklists show that it's incorrect behaviour. Let me reiterate having inconsistencies and incorrect behaviours is perfectly fine, it's simply matter of acknowledging the issue.

 

Multiple proof was posted some time ago. Latest I heard was from a go someone had on the real A-10 USAF sim.

 

Didn't real contracts call for 775 ITT during climbs? We can hardly reach that value in DCS at MAX power. Either ITT has two different meanings in the sim and IRL, the real contracts are wrong, or something is amiss with the engines and their behaviour.

 

e.g. From the 1A-10A-1, Cold Weather Operation:

 

I've never seen 865°C ITT ever in the gauges.

 

From the 1A-10A-1, Sample Inflight Data Log Hi-Lo-Hi Combat Mission:

 

And 775°C ITT can't be MAX power (which is around what we get at MAX in the sim if memory serves) since again from 1A-10A-1, Combat Performance Charts (General):

 

Implying 775°C ITT isn't from a MAX thrust power setting.

 

Just again: there is no certain ITT for an engine in use. It can vary depending on the engine condition, rising as it is worn. THat's why the upper limit is specified.

We even had to add to DCS helicopter engines TV3-117 special parameter to add wear to it, because our testers who fly helos in RL wanted to have individual EGT for each engine.

The only thing I can admit is the low ambient temperature behaviour. As the model was developed there were no detailed data for compressors and fan maps available, so I have to use some analogues. The thrust figures obtained even from this model were correct as we saw later.

Anyway, this engine model much more complicated than the whole airframe and it gives right thrust... ITT is a price for the thrust mainly.

[NineLine]

Then why does the A-10A have an AFM+ FM while the A-10C has a PFM. That does not sound like the same model to me.

 

From the Product Terms post.

 

 

 

 

 

https://forums.eagle.ru/showthread.php?t=122801

 

I think its due to some things that don't translate/work the same without the ASM. But in this case, the two models perform the same.

[Yo-Yo]

No doubt that it is possible to maintain the chopped tone for a bit, I mentioned that more than once, but the thing is, it isn't possible in all conditions which as far as real life evidence suggests it should be possible in all or most conditions, only certain conditions, like a large yaw angle, should induce uncommanded rolls but not pitching or pulling the stick backwards, even while in a roll.

 

No, it only depends on your skill and a degree of understanding the plane. If you hear this chopped tone, it means that you BEYOND the limit. But it does not tell you how far. As you just enter this area - the plane is stable or on the edge of loosing stability. If you have not understood that you are too far beyound the limit it means that you stall the plane deep and badly. That is why this sound que was implemented.

 

THe best point is to catch the moment as steady tone changes to chopped - and hold this AoA...

[Yo-Yo]

I think its due to some things that don't translate/work the same without the ASM. But in this case, the two models perform the same.

 

They do use the same flight and systems models as they are common regardless of avionics modelling, right.

[SCU]

No, it only depends on your skill and a degree of understanding the plane. If you hear this chopped tone, it means that you BEYOND the limit. But it does not tell you how far. As you just enter this area - the plane is stable or on the edge of loosing stability. If you have not understood that you are too far beyound the limit it means that you stall the plane deep and badly. That is why this sound que was implemented.

 

I don't doubt that, not at all. All that I am saying is that the wing drop isn't true to life, it's an inaccuracy, or a bug, I don't know which but I have pointed out that in real life A-10s it never happens, at least in the videos I watched in youtube which I have shared many in here, and many others I haven't shared yet. :)

[NineLine]

I don't doubt that, not at all. All that I am saying is that the wing drop isn't true to life, it's an inaccuracy, or a bug, I don't know which but I have pointed out that in real life A-10s it never happens, at least in the videos I watched in youtube which I have shared many in here and many others I haven't shared yet. :)

 

It can be a difference from simulation to real life... not matter how good our controllers are, we are not sitting in a real A-10, we can pull, push or whatever beyond limits that an A-10 pilot can due to feedback from motion, g's and wanting to live...

 

Just because there isnt a Youtube video of a wing drop doesn't mean it cant happen...

[cichlidfan]

They do use the same flight and systems models as they are common regardless of avionics modelling, right.

 

Then what, specifically, is different in the flight models? Avionics are part of systems modelling not flight modelling so the systems modelling should not be relevant.

[Yo-Yo]

Then what, specifically, is different in the flight models? Avionics are part of systems modelling not flight modelling so the systems modelling should not be relevant.

 

Ok, please tell me how HYDROLICS depends on new AVIONICS in A-10C... Or kinematics of the landing gear?

Or engines and their governors, for example? Or airframe aerodynamics?

 

And sorry, possibly I could not be right about ALL systems migrated to 10A from C, it needs to be clarified.

 

But concerning the all things FM is dependant on - it is right.

Edited August 9, 2017 by Yo-Yo

[cichlidfan]

Ok, please tell me how HYDROLICS depends on new AVIONICS in A-10C... Or kinematics of the landing gear?

Or engines and their governors, for example? Or airframe aerodynamics?

 

That is what I was asking.

[SCU]

It can be a difference from simulation to real life... not matter how good our controllers are, we are not sitting in a real A-10, we can pull, push or whatever beyond limits that an A-10 pilot can due to feedback from motion, g's and wanting to live...

 

Just because there isnt a Youtube video of a wing drop doesn't mean it cant happen...

 

So what you're saying is that it's working as intended? Is it specifically mentioned anywhere in flight specifications that the wingdropping is something that happens at high AoA's in the A-10?

 

Also about the difference between sim & reality, I have, in this thread, linked to a video of an airforce simulator where cadets (who aren't pilots) try it out for the first time and make some hard pulls into the chopped up tone, just like a new guy would in DCS, all without the fearsome wing drop, I don't think that military level flight simulators would have inaccurate flight models.

 

Matter of fact here is the video:

&

at the 20 & 52 seconds marks Edited August 9, 2017 by SCU

[NineLine]

So what you're saying is that it's working as intended? Is it specifically mentioned anywhere in flight specifications that the wingdropping is something that happens at high AoA's in the A-10?

 

Also about the difference between sim & reality, I have, in this thread, linked to a video of an airforce simulator where cadets (who aren't pilots) try it out for the first time and make some hard pulls into the chopped up tone, just like a new guy would in DCS, all without the fearsome wing drop, I don't think that military level flight simulators would have inaccurate flight models.

 

Matter of fact here is the video:

&

at the 20 & 52 seconds marks

 

The SME for the F-15C PFM also stated he had never flown a more realistic version of the F-15C than what was in DCS, including simulators he has trained on over his career. Is it possible the FM on the DCS version surpasses the FM in those videos?

[Yo-Yo]

That is what I was asking.

 

Ok, that's the correct info: both A and C use THE SAME code and data for FM and systems, but the systems are controlled in a simplified way because of non-clickable cockpit. For example, engine start is exactly the same A-10C has but the cockpit switches sequencies are intiated automatically as assigned for ENGINE START button is pressed. It's exactly as an scripted auto-start for 10C.

[SCU]

The SME for the F-15C PFM also stated he had never flown a more realistic version of the F-15C than what was in DCS, including simulators he has trained on over his career. Is it possible the FM on the DCS version surpasses the FM in those videos?

 

Perhaps that's the case in the F-15, I tried it and I really LOVE it. But back to the A-10, I have provided real life A-10 video proof, real life manual (dash 1) proof as well as an airforce simulator video, all supporting my argument. I have no doubt whatsoever that the A-10C in DCS flight model is spot on, but only almost so. There are still a few issues here and there including the one that is the subject of this thread.

[NineLine]

Perhaps that's the case in the F-15, I tried it and I really LOVE it. But back to the A-10, I have provided real life A-10 video proof, real life manual (dash 1) proof as well as an airforce simulator video, all supporting my argument. I have no doubt whatsoever that the A-10C in DCS flight model is spot on, but only almost so. There are still a few issues here and there including the one that is the subject of this thread.

 

But you havent provided any proof that it is not us, the user pulling manoeuvres a normal pilot wouldnt, and then causing the aircraft to perform out of limits. In DCS you can do things a normal pilot wouldnt perform, and in that it will cause the FM to respond out of spec, and many times causing your virtual pilot to die. Yo-Yo showed that if you pull until chopped tone, then hold, you wont drop the wing... which is probably the point of the tone, right?

[Yo-Yo]

So what you're saying is that it's working as intended? Is it specifically mentioned anywhere in flight specifications that the wingdropping is something that happens at high AoA's in the A-10?

 

Also about the difference between sim & reality, I have, in this thread, linked to a video of an airforce simulator where cadets (who aren't pilots) try it out for the first time and make some hard pulls into the chopped up tone, just like a new guy would in DCS, all without the fearsome wing drop, I don't think that military level flight simulators would have inaccurate flight models.

 

Matter of fact here is the video:

&

at the 20 & 52 seconds marks

 

Regarding this DM and graphics...

 

 

To be serious there are several levels in such trainers... for example, the desktop trainer for A-10 does not use AFM but it is indeed of military level...

There are a lot of trainers that are procedure trainers, or they have some additional simplified level means - even DCS FM has SIMPLIFIED level with no stalls, auto rudders and takeoff assistance.

 

What I see in the video you quoted... at 0-22 an invisible spring kicks AoA down, andI can not say exactly who did it - the cadet or an assitant.

At 0-46 - the same "spring" movement and no tone at all is heard.

At 0-58 the cadet is balancing between stady and chopped, that is right the same you need to practice in DCS.

[SCU]

But you havent provided any proof that it is not us, the user pulling manoeuvres a normal pilot wouldnt, and then causing the aircraft to perform out of limits. In DCS you can do things a normal pilot wouldnt perform, and in that it will cause the FM to respond out of spec, and many times causing your virtual pilot to die. Yo-Yo showed that if you pull until chopped tone, then hold, you wont drop the wing... which is probably the point of the tone, right?

 

Well, that applies to all the other planes in DCS, and the ones I have tried didn't have wing drop the ones that had it it wasn't nearly as early and aggressive), such as the F-15 that you just mentioned, the Mirage-2000C and the SU25 frogfoot, so why is the A-10 singled out with this issue?

Yo-Yo's video had wing drop too, at about the 11900 feet, pretty aggressive too.

[mytai01]

Based on??

 

Vapor over wings is on the Todo list.

 

I forgot to post the video I based my observation on. It's link is on my July post above.

[GGTharos]

In the real aircraft you can feel a bunch of things: The buffeting associated with a certain AoA, the G's etc.

 

Here's why this is important: As Yo-Yo mentioned, the chopped tone only indicates that you have surpassed a certain AoA value. Not by how much. At the point he enters the uncommanded roll, he is still pulling the same G as before, but airspeed has dropped significantly. This means that the AoA has increased, and probably significantly so. Whether the wing drop is accurate or the nose should just drop isn't even the issue - your (apparent, correct me if I'm wrong) expectation that you should be able to 'ride it like in the video' is incorrect because what's happening in the video what Yo-Yo (And you) are doing are different things.

 

The pilot there is maintaining an AoA while Yo-Yo stops maintaining the AoA at the end. In flying things, you get punished for such excess.

 

Perhaps that's the case in the F-15, I tried it and I really LOVE it. But back to the A-10, I have provided real life A-10 video proof, real life manual (dash 1) proof as well as an airforce simulator video, all supporting my argument. I have no doubt whatsoever that the A-10C in DCS flight model is spot on, but only almost so. There are still a few issues here and there including the one that is the subject of this thread.

[SCU]

What spring? What I interpret this as is that it is the normal stall behaviour where you have reach max AoA and can't pull any longer, I think it would be silly if the A-10 engineers would make the chopped stall tone that critically close to such an aggressive and interfering stall behaviour, uncommanded roll is a pretty serious thing to have and it would be common sense for the A-10 engineers or programmers to have the chopped tone much earlier that such behaviour if it existed in real life.

[mytai01]

Let me give you an example of why watching a YouTube video is not a good reference. How much fuel is in that aircraft?

 

I had 20% fuel, no bullets, no flares/chaff, no weapons. It still flew like a pregnant sow.

[GGTharos]

What do you mean 'much earlier'? How 'much earlier' should it be? Do you have some numbers? :)

 

I believe you're still mis-understanding. The value at which the chopped tone triggers is reasonable. The fact that you keep the stick peeled back and expect something else is the unreasonable part.

 

The chopped tone tells you that you have exceeded a certain value. It's quite easy to exceed it by a lot once you reach it, in particular since we, as virtual pilots, have no other means of sensing the increase.

 

What spring? What I interpret this as is that it is the normal stall behaviour where you have reach max AoA and can't pull any longer, I think it would be silly if the A-10 engineers would make the chopped stall tone that critically close to such an aggressive and interfering stall behaviour, uncommanded roll is a pretty serious thing to have and it would be common sense for the A-10 engineers or programmers to have the chopped tone much earlier that such behaviour if it existed in real life.

[NineLine]

What spring? What I interpret this as is that it is the normal stall behaviour where you have reach max AoA and can't pull any longer, I think it would be silly if the A-10 engineers would make the chopped stall tone that critically close to such an aggressive and interfering stall behaviour, uncommanded roll is a pretty serious thing to have and it would be common sense for the A-10 engineers or programmers to have the chopped tone much earlier that such behaviour if it existed in real life.

 

We really need to see how you are flying at this point. Maybe once you get back into DCS you can include a track of a video with the control display up...