[NO BUG] FM bug due to CG being initially too far forward then shifting aft...

Hi,

We all know that the center of gravity (CG) of any aircraft might find a longitudinal shift depending on fuel status, but after some good hours and tiring patience that I had to take to see what happens and why do I sometimes get a pitch stable or unstable aircraft (and the difference is quite high), what I found is nothing else but a big time hidden bug! Here's what happens:

Check the "unlimited fuel" option from the mission editor in order to not let the fuel affect the test for an accurate spotting of the bug:

Between 1% and 11% and also between 60% and 100% (inclusive) fuel, clean wings and landing gear up, the Flanker doesn't behave at all like having a very reduced static stability margin at lower alpha and become statically unstable (negative static stability margin) as it's supposed to happen and the maximum achievable AoA (positive only so far) with direct pitch control is much lower than it's suppose to be (full aft stick barely keeps the AoA at 35..40) and is quite comparable to that of an F-15. No matter how would you play with your AoA at any given times through cobras, tailslides or the questionable negative deep stall, the plane remains highly stable.

Somehow if the fuel status is between 12% and 59% (inclusive) under the same configuration (clean wings, gear up), if for whatever reason you go past "X" positive or negative AoA (lost my patience to find out exactly at what alpha), after the plane gets back to normal flight (lower than critical AoA), the plane becomes statically unstable above 20..25 AoA (20 AoA when the fuel is below 12% and 25 AoA when it's above 59%) as it normally should be by default. This bug shifts the CG too far ahead of the CP thus making the plane unrealistically stable after the plane is respwaned and only after the AoA goes past a negative or positive value above stall, the CG finally moves to where it's suppose to be by making the aircraft have a very reduced static stability margin up to 20..25 AoA and become statically unstable above that AoA, pretty possible just like the real plane also behaves.

Here's a track of the FM behavior with clean wings:

The Su-27's CG shifts to where it should be above some negative AoA only with clean wings.trk

Now keep in mind what happens depending on instantaneous fuel status when the gear is up and the wings are clean and check out what happens with the CG when the gear is down and/or you have loadout. With gear down and loadout the fuel percentages where the CG instantly shifts above some AoA have changed. Now only between 1% and 11% fuel and between 72% and 100% the plane remains very nose heavy no matter how you play with the AoA and only between 12% and 71% it is less nose heavy by default and as it should be, but now after you pass above some negative/positive AoA (high values anyway) the CG moves forward, where it should not suppose to be and makes the plane incredibly stable once again.

Here's a track of the FM behavior with loadout:

The Su-27's CG shifts abnormally forward above some negative AoA with wings loadout.trk

This weirdo bug is related to both instantaneous fuel status, loadout and gear position and it's also weird that just 1% of more fuel (ex: from 11% to 12% or from 59% to 60%) the behavior changes dramatically. Just 1% more or less fuel and the CG instantly shifts very much once you go above some positive or negative AoA.

Proof that the Su-27's CG is shifted too far forward on each plane respawn until some AoA is pas.trk

Now, another thing...! Of course that the loadout, gear, leading edge droops and flaps all affect the Cm vs AoA (pitching moment coefficient versus alpha), but not like this..., this is another problem that needs to be addressed because it is an exaggerated effect by how it's simulated and it's also opposite to what it should be! Normally the loadout, the gear, the droops and the flaps will all move the center of drag lower on the plane's vertical axis and aerodynamically the plane's Cm (pitching moment coef.) become more negative (nose down tendency), but what we see in DCS is opposite with gear down and/or weapons,... we see a Cm that becomes less negative (closer to zero) or even positive (above some AoA) when the gear is down and/or the wings have loadout. The effects of landing gear, LE/TE devices and loadout on the pitching moment should be reversed and not so great as they are at the moment! How does this happen?

With honest respect, please re-check!

Regards!

I think the bug you have found is not related to the flight model, but instead the fuel system when using unlimited fuel.

Having watched your track, where you fly around testing max AoA with unlimited fuel, looking at the fuel gauge, I have noticed that at around 01:10 into the track your fuel magically changes from 1200kg-ish to 2100 kg. That seems to be the cause of the instant CG shift.

I have tested the behaviour with normal limited fuel, when there is no bug, and the CG really, noticeably changes as the fuel gradually drops from 2100kg to 1000kg. The effect is smooth and proportionate to the change of fuel.

Again, my conclusion: The FM is not bugged, the fuel system has a bug, when using unlimited fuel (magic inflight refueling)

I do not understand what your second track, where you land the plane is supposed to show us.... :)

@HWasp

I wondered about that. My dad recently started learning, and has unlimited fuel and invulnerability turned on, first thing I thought was 'that probably screws everything up...'

I do not understand what your second track, where you land the plane is supposed to show us.... :)

I had to modify the paragraph with explanation before the 2nd track because I forgot that the CG shift now reverses when you have loadout and makes the plane highly stable after some AoA is passed, but I don't get why you don't understand this bug, because I clearly stated that only when passing above SOME AOA the CG moves like crazy back or forth (depending on loadout which is also abnormal)!

In the 3rd track, after the first landing, at what speed did the plane started pitching up (raising the nose gear) with full aft stick (direct pitch control) and at what speed did the nose rise at the second time? Yes, the difference in speed means just one thing: CG shift. I've done that track just to make sure and prove that the bug is related to a CG movement only and not a CP (as it could've possible been the case). Because on the ground you now you have a different arm between the CG and the main landing gear, thus the more or less force is needed on the elevators to counter the stabilizing moments (the moments that keep the plane on the ground).

By all you replied I believe that you didn't understand everything I wrote, but only partial! There is indeed a smooth transition of the CG due to fuel as you say and that can only be witnessed after the plane is respawned and you didn't yet go above X negative AoA, but next to that there's also a damn abnormal CG transition due to AoA. How do you explain that? That's what I've wasted a dozen of hours on to find out what's going on and why sometimes the plane is extremely nose heavy (worse than the F-15 or similar) and some other times it's static stability is what it's normally suppose to be. There are some magic fuel status values (one percent more or less and you have a very different stuff going on, the CG shifts dramatically, NOT SMOOTH) which depending on loadout and/or gear position and ONLY after getting past some "X" negative AoA, the CG abruptly shifts fore or aft.

Again..., without loadout and between 12% and 59% fuel, the CG moves aft (where it should've been all along) instantly and only after passing through "X" negative AoA.

With external loadout and between 12% and 72%, the plane's CG is where it should be this time, but this time, if for some reason you pass above some negative AoA, the CG moves forward.

So this bug is quite complex, and YES, most of what's happening with the abnormal CG shift is a bug, only by a small amount the CG moves just depending on fuel, and that shift is small and looks very correct.

Again, the CG doesn't move due to fuel (but just slightly, which is normal)..., it moves when the AoA is above some negative (through deep stalls effects) value. This is the problem.

Regards!

I was trying to point out my observation about the fuel SUDDENLY changing (seemingly the change is triggered by AoA). Are you sure that is not related?

Did you experience this problem flying with limited fuel as well?

I really don't mean to be disrespectful, but your initial post is hard to follow.

I was trying to point out my observation about the fuel SUDDENLY changing (seemingly the change is triggered by AoA). Are you sure that is not related?

 

Did you experience this problem flying with limited fuel as well?

 

 

I really don't mean to be disrespectful, but your initial post is hard to follow.

What HWasp is trying to tell you as gently as possible is that all of your testing with the sim set to "unlimited fuel" is invalid because "unlimited fuel" does not work the way you assumed. The fuel quantity will, indeed, change instantanously to a greater amount and you have not controlled for that.

I was trying to point out my observation about the fuel SUDDENLY changing (seemingly the change is triggered by AoA). Are you sure that is not related?

 

Did you experience this problem flying with limited fuel as well?

 

I really don't mean to be disrespectful, but your initial post is hard to follow.

Hello again,

I have only tested these phenomena using unlimited fuel only!

Now I have tested the same things with fuel consumption also. Some things don't happen anymore but some still do. Of course..., abnormal things, cause almost nothing is normal so far!

What doesn't happen anymore with unlimited fuel is that the CG is no longer trigger shifted by some negative AoA, but what still happens is the abnormal CG shift with fuel status. With or without weapons and gear, the CG's shift behavior only on fuel remains the same as it happened with unlimited fuel also. Between 100% and some 70% (I didn't have the patience to waste my time finding the exact value) the plane is more stable. Between about 70% and some lower fuel percentage, the plane is a bit less stable. Between the lower fuel percentage and empty, the plane once again becomes more stable O.o! How do you explain that? You can't, but the facts can! It's called: DCS and some people became too blind to recognize the problems in it!

In the following tracks we can see how the maximum achievable constant AoA (which is affected by the CG and CP) with full negative elevator deflection will vary abnormally with fuel status, weapons loadout and landing gear position.

In this track we can see how the max constant AoA will vary from 100% fuel to almost empty tank. First the AoA is merely around 35-37 AoA. This is not a Su-27 simulation, but some other fighter in the shape of a Flanker. After the fuel drops below around 8000kgf the CG shifts aft a bit thus the AoA increases by some amount, yet still not enough to simulate the very reduced stability margin of a real Su-27 or at least not by my expectation.

Clean, the CG oscillates randomly with fuel status.trk

In this track the maximum constant AoA is almost 10 degrees higher just because we have weapons loaded on the wings, which is opposite to reality simply because the center of drag should now be further down the plane's Z axis (if the positive Z axis direction would be considered towards the top of the plane) in contrast to a clean weight configuration and also the plane's CG should be a bit forward now (because the weapons all together have their CG a bit forward of the clean plane's CG). These 2 effects should only make the aircraft have a greater static stability margin (a thing that average people use to call: nose heavy) thus an even lower constant maximum obtainable AoA. Instead we have something called: DCS simulation, which once again simulates it's own kind of world apart from the real world, yet it dares to dares to say that it's realistic.

Here it is: weapons loaded (which have a forward CG) and lower the drag center, but the result is an aft shift in CG.

With weapons, the CG goes aft and still oscillates randomly with fuel status.trk

As you've seen these, now the most delicious part comes in: the landing gear.

Also with landing gear out, the CG goes aft.trk

Reality: the gear out lowers the CG and shifts it a bit aft while the center of drag usually shifts towards the bottom of the plane more than the CG does. Result: an easily noticeable down pitching moment.

DCS: the gear out may lower the CG (can't tell) but drastically shifts it aft while the center of drag either doesn't shift down at all or it's downward shift its very low. Result: an easily noticeable up pitching moment.

Conclusion...: Reality is wrong and DCS is right! Now tell me that I'm wrong folks!

Now I don't want to be impolite either, but I'm extremely sick of how I am treated on the forums when discussing serious flight model issues (most of the time) and being replied by people who still have a lot to learn about flight dynamics and aerodynamics which only makes me feel that I'm wasting a lot of time and patience for nothing..., because as I see the things are going..., these issues and others will NEVER be fixed because they see that the ratio between those who witness something wrong in the simulation and those who don't understand or witness anything is very low (the ratio might be somewhere at 0.1), so they are confident that they can continue on like this (stealthy) and only take people's money for something that they pretend to be realistic but don't provide solid answers to prove it, but just words and ask us to provide solid proofs (they throw the ball in our field) to tell that they're wrong and even if we'd do that, they still wouldn't accept it, period...! At least this is how I sense it! I don't brag about my own at all, cause I'm not looking for that or for any recognition. All I'm trying to do is to prove and bring out the simulation abnormalities that we see happening inside out with the FMs in DCS. Yes, there are many FMs which are simulating stuff with an intolerable error against reality. We can never talk about 100/100 realism in any simulator, as someone was trying to point out by contradicting me and other serious people (who are trying to prove what's wrong), yet that someone failed to recognize that in DCS (nowadays only...) in some cases the FM reaches just some 30-40/100 (60&-70% error) versus reality.

Good day!

What HWasp is trying to tell you as gently as possible is that all of your testing with the sim set to "unlimited fuel" is invalid because "unlimited fuel" does not work the way you assumed. The fuel quantity will, indeed, change instantanously to a greater amount and you have not controlled for that.

You are correct friend. That's true, I haven't tested without unlimited fuel because I couldn't even guess that yet another bug lies in there. Please read the above post and watch the new tracks and see how things actually vary depending on limited/unlimited fuel.

As a short list of what's going on wrong with the Su-27 (that I and others personally consider to be abnormal, things which have no link or proof on the real plane's behavior) and yes..., also the list of what can normally be fixed by ED, unless they don't even want to look at it:

-The reality unconfirmed negative pitch static stability margin (unstable) beyond -20 AoA which makes the DCS Flanker get into a wonderful negative deep stall where it settles at around -50 AoA

-The reality unconfirmed relatively high static stability margin (highly stable) if the plane finds itself at fuel statuses between empty tank and some 10%-15% fuel and also between some 70% and 100% fuel. ONLY BETWEEN around 15% and 70%, the plane finds a bit reduced (but not enough form my perspective) static stability margin. So, it's kind of werid no? At first, with 100% all the way until some 70%, the CG is one position, then abruptly, NOT SMOOTHLY (see the track) the CG moves very slightly aft (increasing the max constant AoA by some 8-10 degrees) and then once again below some fuel percentage the plane's CG moves forward? Just by judging how the CG wobbles fore and aft when the fuel status only goes down, not up, everyone can understand there's something abnormal going on!

-The reality unconfirmed static stability margin reduction once the plane is loaded with weapons (AA missiles for instance) or when the landing gear is deployed.

With honest respect,

Mav!

I really don't want to brag about it, but I have manged to convince the Developers to correct their flight models TWICE already with rather short and clear posts consisting more or less accurate data and documents. They do care about this, even though not everything is perfect.

If I would think, that there is something wrong, I would start with the SU-27SK flight manual, available on the internet, searching for information like:

-How is the fuel system working? What system is there to stabilize the CG in the correct region by controlling the fuel tanks? How does all this effect the CG position according to the manual? And so on...

Mav, the way you're treated is directly related to your methodology. Nobody cares about your self proclaimed expertise. You cannot use napkin math, conjecture, and YouTube videos to dispute stuff. It wouldn't be enough to make scientists revise their theories on black holes, and it isn't enough to make ED recode a flight model.

You must provide solid sources beyond 'I am an expert in aeronautics'. Even if you're right, you must provide an actual credible reference to back it up. 'Because anybody smart would agree with me' is not good enough.

And certain folks around here with their hellbent approach to things undermine their own goals. When you come off as blowhards, people do indeed dismiss you.

Just a couple of questions:

There is at least one known incident with Su-27 getting into unrecoverable upside down spin after wrong done tailslip (wrong pitch exceeding 75-80 degrees). Both pilots had to eject.

Hello Yo-Yo,

I'd be pleased to talk about it. Can you share us more light into that through a better detailed analysis? For example, how long (altitude loss or time spent) did the plane remain in that condition? How were the pilots inputs and elevators responses, thus the plane's response to those inputs? How was the alpha varying according to pilot inputs in that condition? Many of these types of questions for a better look into it and therefore a conclusion of error between the DCS simulation and reality. Let the numbers step in and tell the truth. From my point of view (although I may miss something from the details, reason why I may be wrong), the vortex generated by the LERX would happen for the negative AoAs as much as for the positive ones, except that at negative AoAs it's strength may be a little weaker (not stronger because the LERX is asymmetrical towards increasing the vortex strength at positive alpha), but still, the vortex should flow over the underside of the wing and past the elevators (on the elevators doing it even better than at positive AoAs) and still maintain a good quality airflow up to a vortex breakdown AoA (which shouldn't happen at -20 AoA only, but much higher by common sense, I'd say -40..-45AoA). Yes, this is my perception, that this plane have a slight increase of static stability margin (although it may still be negative, it's towards more stable) throughout the whole Cm versus negative AoAs function in comparison to the Cm versus positive AoAs function. For short, from my opinion, the plane should find an overall slightly increased pitch stability (or a slightly reduced instability, depends from which way one may want to see it) at negative AoAs than it would find at positive AoAs. Somehow though in the sim, we have just the opposite. We have a very highly stable aircraft at all positive AoAs (there is no positive AoA below/above which the plane's static stability margin is negative), but at negative AoAs beyond -20, the static longitudinal stability margin becomes negative (the plane goes away from the AoA where it should trim according to, for example, the elevators), thus the plane is unstable and now tends to pitch accelerate towards higher negative alpha.

Again, from how I consider, the plane should find a reduced static stability margin (but positive), with elevators at zero degrees deflection (the elevators being at 0 degrees is a fundamental condition when analyzing a plane's pitch stability) up to some 20..25 AoA. The F-16C for example, with elevators at 0, meets exactly zero static stability (statically relaxed) at 15 positive AoA. Below 15 AoA, with elevators at 0 deflection, the F-16's static margin is positive (pitch stable plane), above 15 AoA, with elevators 0, the static margin becomes negative (pitch unstable plane). Our aircraft, the Su-27, from my opinion, should pass through the relaxed static stability margin at around 20..25 AoA (I don't have access to it's real Cm2AoA, maybe you do, yet I'm confident the Su-27 is only slightly more stable (and/or less unstable) than the F-16 at any AoA between 0 and positive 90) and above 20..25 AoA, with elevators at 0 deflection (luckily on Su-27 we have an arc with degrees painted ahead of the elevator's leading edge) the plane should now become statically unstable unless the elevators are deflected trailing edge down (pitch down) before the wing's AoA reached a value from where the Cm of the wings and fuselage combined is positive enough to overcome the down pitching moment (negative Cm) available from the full down elevators deflection or unless the elevators have somehow stalled (elevators which stall too quickly in DCS and the lift after stall becomes way too low.

Do you have real CG movement diagram due to fuel management to compare and to state that CG movement in DCS is wrong?

I don't need to have any diagram against plain sight bugs in the end...! Why are you trying to be ridiculous? I thought that you are the most knowledge based around! I provided a few tracks here that show what happens wrong in plain sight, why do you have to try arguing with me instead of watching the tracks? Can't you see that with fuel status decreasing from 100% to when the fuel weight is just below 8000kgf the AoA jumps some 8 degrees instantly? Then after the fuel reaches somewhere below 7000kgf, the AoA drops some 8 degrees (comes back to where it was between 100% and 8000kgf). At below 6000kgf, the AoA again instantly increases some 8..9 degrees AoA. Then again, below some 1500kgf, the plane becomes more stable, AoA capping out around 40..41 as average. Do you we all (who find these things during actual play) look like idiots and accept this to be normal just because you, ED or anyone else forces us to believe? How could you say what you say? How long should people working for ED keep on not recognizing the truth just to make it look like their simulator is realistic? Please, don't pretend you don't see what's wrong in there!

Do you know what happens with control algorythms as you deploy landing gears?

Wow! Just wow! Control algorythms? Man, do you even know what you're talking about? You blow my mind with your incoherent answers!

This is kind of tragic, seriously! How could you even question the controls surfaces (the elevators are not affected anyway by gear during direct pitch control ASC, but only with FBW ON) if the plane starts to pitch up only due to landing gear extension and/or finds a reduced pitch stability at positive AoAs when the weapons are loaded? Do the Su-27's controls affect the f#$@ing center of gravity man? I'm kind of speechless now! Are you helping ED develop their FMs? That might make sense then! Again..., do the controls make any sense to you regarding this subject and to what you find in those tracks? As long as you have the recording and also as long as maybe you don't even know how the plane should behave with gear down or external loadout (ie: CG repositioning, global drag vector (drag center) and global lift vector shifting (both lift and drag vectors being affected by pressure distributions)), then what are we talking here...? As long as the FMs in DCS are built only through some equations (who knows how validated they are) which sometimes develop abnormal aerodynamic functions and I will name the most important ones that are having huge problems in DCS: lift coefficients at null AoA, lift slopes (lift coefs. vs AoA), stall onset AoAs, stalled lift (lift available beyond stall AoA), lift functions between stall AoAs (positive and negative) and +/-90AoA.

As I repeat myself: The lowered gear and also the weapons loaded on wings should only increase the negative Cm in the aerodynamic center, NOT increase it as DCS simulates. With many occasions, things that are normal in the real world..., are turned upside down in DCS World.

I can only suggest that your answers will be negative, so, your criticism is based on your own thoughts but not on the facts... sorry.

Well, giving the above facts, do you still wanna talk about criticism? I'm not even here for criticism after all! If it were to have these discussions criticism oriented, you could make sure that only little has been done so far.

Instead of complaining about the clients criticism (nothing wrong from my opinion after spending more than 1000$ myself on modules, from which only a few deserve some respect) for pointing out unresolved and still questionable things you or ED should start giving credible answers about the FM, but all you guys say is: "AAHMM! We did it good, we don't need to give you answers"! Is that the kind of politics go on at ED? Look at other flight simulators which do actually cover a lot more in aerodynamics (all aero coefficients versus Mach and Beta) than DCS and it's a fact! Just watch their discussions and see how every question is being respectfully replied by professional aeronautical engineers, not some wannabes, with detailed explanations on how things work and how the FMs are being done.

I personally won't take for granted the way that planes behave (in terms of flight dynamics and aerodynamics) in this World of DCS (as most random people that are trying DCS actually more or less do).

I'm kind of speechless now! Are you helping ED develop their FMs?

LOL

That's quite funny, please keep it up :). The part about facts (lack thereof) is priceless :D.

Jack where are you? The show isn't complete without Statler and Waldorf :music_whistling:

Hello Yo-Yo,

I'd be pleased to talk about it. Can you share us more light into that through a better detailed analysis? For example, how long (altitude loss or time spent) did the plane remain in that condition? How were the pilots inputs and elevators responses, thus the plane's response to those inputs? How was the alpha varying according to pilot inputs in that condition? Many of these types of questions for a better look into it and therefore a conclusion of error between the DCS simulation and reality. Let the numbers step in and tell the truth. From my point of view (although I may miss something from the details, reason why I may be wrong), the vortex generated by the LERX would happen for the negative AoAs as much as for the positive ones, except that at negative AoAs it's strength may be a little weaker (not stronger because the LERX is asymmetrical towards increasing the vortex strength at positive alpha), but still, the vortex should flow over the underside of the wing and past the elevators (on the elevators doing it even better than at positive AoAs) and still maintain a good quality airflow up to a vortex breakdown AoA (which shouldn't happen at -20 AoA only, but much higher by common sense, I'd say -40..-45AoA). Yes, this is my perception, that this plane have a slight increase of static stability margin (although it may still be negative, it's towards more stable) throughout the whole Cm versus negative AoAs function in comparison to the Cm versus positive AoAs function. For short, from my opinion, the plane should find an overall slightly increased pitch stability (or a slightly reduced instability, depends from which way one may want to see it) at negative AoAs than it would find at positive AoAs. Somehow though in the sim, we have just the opposite. We have a very highly stable aircraft at all positive AoAs (there is no positive AoA below/above which the plane's static stability margin is negative), but at negative AoAs beyond -20, the static longitudinal stability margin becomes negative (the plane goes away from the AoA where it should trim according to, for example, the elevators), thus the plane is unstable and now tends to pitch accelerate towards higher negative alpha.

 

Again, from how I consider, the plane should find a reduced static stability margin (but positive), with elevators at zero degrees deflection (the elevators being at 0 degrees is a fundamental condition when analyzing a plane's pitch stability) up to some 20..25 AoA. The F-16C for example, with elevators at 0, meets exactly zero static stability (statically relaxed) at 15 positive AoA. Below 15 AoA, with elevators at 0 deflection, the F-16's static margin is positive (pitch stable plane), above 15 AoA, with elevators 0, the static margin becomes negative (pitch unstable plane). Our aircraft, the Su-27, from my opinion, should pass through the relaxed static stability margin at around 20..25 AoA (I don't have access to it's real Cm2AoA, maybe you do, yet I'm confident the Su-27 is only slightly more stable (and/or less unstable) than the F-16 at any AoA between 0 and positive 90) and above 20..25 AoA, with elevators at 0 deflection (luckily on Su-27 we have an arc with degrees painted ahead of the elevator's leading edge) the plane should now become statically unstable unless the elevators are deflected trailing edge down (pitch down) before the wing's AoA reached a value from where the Cm of the wings and fuselage combined is positive enough to overcome the down pitching moment (negative Cm) available from the full down elevators deflection or unless the elevators have somehow stalled (elevators which stall too quickly in DCS and the lift after stall becomes way too low.

 

 

 

I don't need to have any diagram against plain sight bugs in the end...! Why are you trying to be ridiculous? I thought that you are the most knowledge based around! I provided a few tracks here that show what happens wrong in plain sight, why do you have to try arguing with me instead of watching the tracks? Can't you see that with fuel status decreasing from 100% to when the fuel weight is just below 8000kgf the AoA jumps some 8 degrees instantly? Then after the fuel reaches somewhere below 7000kgf, the AoA drops some 8 degrees (comes back to where it was between 100% and 8000kgf). At below 6000kgf, the AoA again instantly increases some 8..9 degrees AoA. Then again, below some 1500kgf, the plane becomes more stable, AoA capping out around 40..41 as average. Do you we all (who find these things during actual play) look like idiots and accept this to be normal just because you, ED or anyone else forces us to believe? How could you say what you say? How long should people working for ED keep on not recognizing the truth just to make it look like their simulator is realistic? Please, don't pretend you don't see what's wrong in there!

 

 

 

Wow! Just wow! Control algorythms? Man, do you even know what you're talking about? You blow my mind with your incoherent answers!

 

This is kind of tragic, seriously! How could you even question the controls surfaces (the elevators are not affected anyway by gear during direct pitch control ASC, but only with FBW ON) if the plane starts to pitch up only due to landing gear extension and/or finds a reduced pitch stability at positive AoAs when the weapons are loaded? Do the Su-27's controls affect the f#$@ing center of gravity man? I'm kind of speechless now! Are you helping ED develop their FMs? [/i]

YoYo developed the Su-27 FM.

I highly suggest revising your post and removing the insults. Yo-yo knows what he’s talking about and more about the flanker than anyone else here

YoYo developed the Su-27 FM.

 

I highly suggest revising your post and removing the insults. Yo-yo knows what he’s talking about and more about the flanker than anyone else here

You old spoilsport :megalol:

I hoped he finds out for himself who he was trolling.

He's the kind of guy who gets banned for being a jerk, then goes to a popular anti-ED forum and tells them what Nazis run this place that they would ban an innocent damsel such as himself, at which point they all have a circle-jerk orgy of hating :P

You old spoilsport :megalol:

 

I hoped he finds out for himself who he was trolling.

No worries. Ego is an amazing thing. His opinion is worth a thousand Yo-Yos

Come now chaps, there's an obvious solution to this. Anyone who doubts the fidelity of the DCS Su-27 FM, despite the fact that AFAIK it's been tested by and approved by actual Su-27 pilot(s), all one would have to do would be to create one's own mathematical model of how the Su-27 ought to behave under various flight conditions, apply it to an aircraft model (the DCS Su-27 will do nicely) and then submit it to the likes of Anatoly Kvochur, Sergey Bogdan or really any other Sukhoi test pilot for their comments. I'm sure this will reveal all sorts of issues with the DCS FM that those other real Su-27 pilots didn't spot. Oh, hang on... :doh:

You old spoilsport :megalol:

 

I hoped he finds out for himself who he was trolling.

Whoops...didn’t mean to spill the beans :doh:

Truth to be told, the "approved by real operators" statements are way too often on the borderline marketing BS side, happily used by various flight sim producers and racing sim producers to make their software sound more attractive for armchair experts, nerds and anoraks like us. You will find such statements quoted for EVERY single flight or race sim on the market nowadays. And yet, if they're all supposedly approved by real pilots/drivers, why do they work and feel so different sometimes? That's why I wouldn't treat these "approvals" like words of God himself.

Not to mention that neither real pilots nor drivers test their expensive machinery in all ridiculous attitudes and regimes like we do in our virtual crates. They can approve basic performance figures in stable flight conditions, behaviour in most popular manoeuvres, but how far does their experience beyond critical regimes go?

But I digress. Maverick may or may not be right, but I've never seen him providing any reference materials to back up his thoughts on chosen airplane and that path just leads to nowhere. As recent thread in P-51 section shows, even Yo-Yo can make mistakes, or not notice an error in the FM code being introduced with some recent patch, but a well documented investigation by community member lead to FM fix nevertheless. If Maverick tried to follow the same route, I think the results would be more constructive for all of us.

Truth to be told, the "approved by real operators" statements are way too often on the borderline marketing BS side, happily used by various flight sim producers and racing sim producers to make their software sound more attractive for armchair experts, nerds and anoraks like us. You will find such statements quoted for EVERY single flight or race sim on the market nowadays. And yet, if they're all supposedly approved by real pilots/drivers, why do they work and feel so different sometimes? That's why I wouldn't treat these "approvals" like words of God himself.

 

Not to mention that neither real pilots nor drivers test their expensive machinery in all ridiculous attitudes and regimes like we do in our virtual crates. They can approve basic performance figures in stable flight conditions, behaviour in most popular manoeuvres, but how far does their experience beyond critical regimes go?

I understand your point, and with many other games I agree entirely about it being largely marketing nonsense, but as NineLine pointed out, DCS is somewhat unique in that respect due to the sheer amount of experience they have available.

On the wider point, by now I don't really understand why the occasional person has such difficulty with the standards demanded of us when reporting bugs and issues when comparing DCS equipment to real life counterparts. I would imagine that flight sims are one of the game types were mathematical modelling and comparison with known real life performance data is most useful. There are endless examples readily available of very well done bug & issue report threads.

Of course not all flight sims are obsessive about that sort of thing, and I wouldn't expect to see detailed comparisons with real life hardware in a game such as world of warplanes, but surely by now it should be abundantly clear that DCS does and always has striven for obsessive detail and realism. I'd go so far as to say that a large part of the customer appeal of a game like DCS is precisely that quest for ultimate realism. And yet we still see bug reports and commentary that are based on nothing more than "I'm amazing at this and DCS feels wrong."

Ultimately I think this thread has probably reached the end of its utility by now.