A few questions regarding the control system and maneuverability of the su-33

[Ala12Rv-watermanpc]

Hi comrades, I have some questions that might be totally noob but I'm so in the 33 and couln't resolve them searching in the manual and internet.

 

I have spent a few hours testing the new PFM with advanced maneuvers I have seen in videos and such, the thing is, I can't manage to get close with the new PFM to what I see in videos, even after trying several fuel amounts (and clean config of course). I'm not sure if this is because there are no videos of the su-33 in display (at least I couldn't find a single one) but the su-30/su-35/su-37 and maybe those planes are much more capable in aerobatics but I tend to think the 33 should be capable of most of those advanced maneuvers also (somersault for instance).

 

I have tried enabling the DCS control by pushing "S" key but several things I don't understand are happening when messing with the maneuvers and the stability controls of the plane:

 

1- After enabling DCS (DIRECT CONTROL mode), I can perform the cobra maneuver BUT no matter at which speed and angle I do it, it doesn't look as a "proper" cobra, I mean, the plane gets at a 120º angle for a second but also makes a severe climb which doesn't match to what I see in rl videos, for instance here (1:34):

 

 

I tried at a variety of starting pitch angles but the result is the same, too much climbing compared to rl even using idle power during the pull and low speeds (below 400km/h). I think this is also related to the next question.

 

2- I have seen the 30,35 and 37 perform a full somersault (I think its called kulbit), for example here (thanks Vitormoura for the video):

 

 

After lots of tries, I just can't manage to do this maneuver with the 33 PFM. When I try to perform it, the plane doesn't "slide" or "skid" in the air as you can see in the video (I mean that fast or with that "energy") which I guess is mandatory to be able to roll in the pitch axis that fast and so complete the somersault...and that's why I said it was related to the number 1 question, again, the plane climbs a lot during the start of the pull (no matter how fast you make the pull), losing a lot of energy doing so instead of "sliding" or "skidding" creating a brutal vortex as in the video. What am I doing wrong?

 

3- I have noticed by enabling "controls viewer" using RCntrl+enter that the plane uses some kind of "limiters/dampers" for both roll and pitch axes. When DCS is disabled, those limiters seem to actuate over the pitch control only, so you cant exceed some G limit depending on the speed you fly, roll seem unaffected by this, ok.

 

If you eneble DCS, then there is no pitch limiter but, there is a roll limiter whenever you perform a hard pitch pull (you can see how the lateral bars of the controls viewer get closer to the center indicating you cant get more input than that no matter how much you push the stick in the roll axis). The lower the speed, the lower the roll margin which I find odd.

 

Now I wonder, is there any way to TOTALLY REMOVE all those control limiters?? I would like to fly the plane at a totally manual mode (no control system, no FBW, no limiters, etc.) cos I guess this is how those maneuvers are performed). I have read about the ACS system in the manual but I'm not sure if the ACS is enabled in any way by default nor if there is any way to get rid of it (COMPLETELLY), although the manual says there is a " ACS OFF button" (pag 72) I coudn't find such a thing in the key bindings menu.

 

4- I also found that there is a "stick limiter override" key (or something like that) so, when pushed, enables maximum stick deflection in any situation (you can actually see how the stick in the cockpit now moves at the outer limits) and it seems to work in a similar way like the DCS switch. When pushed, you can overide the pitch limiter and make sharper pitch deflections and even break the wings at enough speed, ok...I though that was the answer I was looking for BUT, sadly, this control only works for the pitch and not for the roll.

 

I even wonder what's the purpose of this control as it has the same functionality as the DCS enabler switch as far as I can tell, just seems to be like a "temporal" switch.

 

5- I don't know if this is related to other questions but something I have always noticed in both, the su-27 PFM and now in the su-33 PFM is that both planes tend to auto-stabilize in roll axis...I mean, even applying generous amounts of bank angle, it will slowly recover to horizontal position. I can't remember other planes doing this (at least not to the level the 27 and 33 do it) unless some kind of system is enable to do so (like AP)...I find this extremely annoying as the plane never stays in the position you ask it to be...

 

so I wonder here if there is some control I'm missing which avoids the plane to fully being manually controlled and to fly like most other fighters??, once again I would like to get rid of ALL stabilization systems if possible. Manual is not very clear about ACS/DCS/Stick override, etc, but the fact is both 27 and 33 don't fly as most other planes in DCS (even the M2000 feels more natural with its FBW system enabled).

 

6- Finally, I don't know if maybe I'm asking too much to the PFM or if the differences between the 33 and the 30/35/37 are such that the 33 just can't perform those meneuvers (post-stall maneuvers) but one thing is sure, I think there is something I'm missing with the "control system" of the 33 because the plane seems to be constantly flying "over rails", like there is a constant FBW system kicking in and limiting the plane no matter if you enable DCS, full stick motion or whatever, you can't do "whatever you want" with the controls...

 

 

sorry for the very long thread, hope you, much more savvy pals, could help me with my doubts, thanks a lot!!:thumbup:

Edited September 26, 2017 by watermanpc

[Alfa]

I cannot comment on the more specific aspects of what you are trying to do/expect to be able to do.

 

But as far as I can see both your videos concern maneuvers performed by the Su-37...which has a more sophisticated flight control system and engines with TVC. :) .

[Ironhand]

...

so I wonder here if there is some control I'm missing which avoids the plane to fully being manually controlled and to fly like most other fighters??, once again I would like to get rid of ALL stabilization systems if possible. Manual is not very clear about ACS/DCS/Stick override, etc, but the fact is both 27 and 33 don't fly as most other planes in DCS (even the M2000 feels more natural with its FBW system enabled)...

You're not missing anything to the best of my knowledge. Admittedly I haven't spent a great deal of time in the PFM pit but I can't think of anything that you're missing.

 

As far as the -27s and -33s FBW system is concerned, it is like all the rest except it has an added program overlaying it that makes it mimic the behavior of an aircraft with positive dynamic stability. With the FBW engaged, the aircraft wants to return to its original state. If you are trimmed for straight and level flight and disrupt it, the aircraft will attempt to return to that state.

 

I can't speak to all other DCS FBW aircraft because I don't own them all. But the F-15, for instance, behaves more like an aircraft which has neutral dynamic stability. Once its flight is altered, it remains altered until you alter it again.

 

The difference in the two approaches is easy to see. Trim both for level flight. Slowly decrease your throttle. The Su-27/33 will hold the AoA and begin to descend. Do the same in the F-15 and you will continue in straight and level flight with a gradually increasing AoA. Two different philosophies at work.

[NineLine]

Might help to show vids of what you are doing with controls displayed, also realize that ED simulates the aircraft, that doesnt make anyone here an expert pilot, it may take some time and effort to really perfect any advanced maneuvers in any aircraft in DCS.

[WildBillKelsoe]

Its very frightening that 360° for a F-15 on his tail. I'd be scared.

[NineLine]

Its very frightening that 360° for a F-15 on his tail. I'd be scared.

 

Or he would be happy with all that more jet to shoot at ;)

[Ala12Rv-watermanpc]

Hi, thanks for your replies mates, very appreciated!

 

After a few more tests, I'm starting to think that vectored thrust, as Alfa sugested, must be the key to achieve that instant turn in the air which makes the plane to "drift" generating that extreme vortex and making it almost rotate around it's gravity center during the somersault...that might be what prevents the 33/27 of making this maneuver (the somersault), they tend to "fly" throught the maneuver (the looping) instead of just rotating over its gravity center due to the lower instant turn.

 

The only video I could find about a su-33 in display shows that maybe the 33 just can't do all post-stall maneuvers (the kulbit especially), at least the display is much more conservative:

 

 

@Ironhand: I think you have a great point dude!, it would explain the "different" behaviour of the SU-27/33, sadly, there is no way to get rid of ALL the FBW systems to achieve a fully manual plane. Maybe it would be imposible to fly that way although I don't think so looking at how the m2000 can be flown without the FBW, maybe then we would be able to fly it in a more aggresive way...anyway, I mentioned that the manual talks about a " ACS OFF button" but I couldnt find anything like that, maybe not yet implemented?.

 

@SiThSpAwN: Well, I wish I could upload some videos, sadly with my 1mb upload connection it's a pain in the neck so...:cry:. About not being an expert, well, I guess there is not much to do when trying to perform the kulbit if the plane don't achieve that initial extreme pitch up while retaining a mostly straight flight path...as I said tried with a variety of fuel config and speeds/starting angles but the 27/33 just don't seem to be capable of that instant starting turn nor the subsequent power to turn arround themselves so I guess vectored thrust is mandatory.

 

 

Anyway, even if the 33 just can't perform some post-stall maneuvers like the 30/35/37, what I hate the most in these two planes (27/33) is what I mentioned previously about how the roll input is constrained when performing a pull!!!:mad:...make a generous (high speed) pull and then try to roll the plane to achive a bank angle...YOU CAN'T!!!!:mad:...some damn roll limiter takes place and basically, the plane gets stuck in the positive g turn in the vertical axis...it's almost imposible to fly a barrel roll witouth using the yaw, I mean mixing both PITCH+ROLL is impossible at reasonable speed (once you are stalled you usually can do it).

 

Other planes like the F-5 have no problems fully mixing PITCH+ROLL to the maximum (even you can do it when disabling the stick limiter), so I'm surprised the 27/33 which are more capable planes are restricted in this way :huh:...maybe being a FC level module lacks the implementation of the ability to completelly disable all kind of control systems or maybe the plane just can't do that in RL which I highly doubt.

 

Thanks all for your help guys!!:thumbup:

 

EDIT: Forgot to mention that the closer I got to make the kulbit was in a su-27 in a vertical climb and then, apox at 120º past the vertical pull at max the stick then it kind of make a slight drift. I found best starting the loop (the climb of the loop) at 400km/h and then in the vertical aprox make the max pull. Also, made some nice post-stall maneuvers using asym. thrust though not so "sharp" or clear as the ones you can see in the 30/35/37.

Edited September 26, 2017 by watermanpc

[Ironhand]

...I mentioned that the manual talks about a " ACS OFF button"...

That would be the ACS Reset button. But turning ACS off has no effect on the FBW system except that the ACS commands are no longer available to the FBW. ACS is, in the vernacular, the autopilot system. The closest you'll come to turning the FBW system off is the direct control key (S).

 

...what I hate the most in these two planes (27/33) is what I mentioned previously about how the roll input is constrained when performing a pull!!!...make a generous (high speed) pull and then try to roll the plane to achive a bank angle...YOU CAN'T!!!!...it's almost imposible to fly a barrel roll witouth using the yaw, I mean mixing both PITCH+ROLL is impossible at reasonable speed (once you are stalled you usually can do it)...

I haven't tried this in the -33 but I've always been able to barrel roll the -27 in the past without resorting to using the rudder. Guess I'll need to take another look at it. Or, perhaps, our interpretation of the term differs.

[Ala12Rv-watermanpc]

That would be the ACS Reset button. But turning ACS off has no effect on the FBW system except that the ACS commands are no longer available to the FBW. ACS is, in the vernacular, the autopilot system. The closest you'll come to turning the FBW system off is the direct control key (S).

 

 

I haven't tried this in the -33 but I've always been able to barrel roll the -27 in the past without resorting to using the rudder. Guess I'll need to take another look at it. Or, perhaps, our interpretation of the term differs.

 

When I said "make a generous (high speed) pull and then try to roll the plane to achive a bank angle...YOU CAN'T!!!" I meant doing the roll AT THE SAME TIME (so mixing) as you make the pitch (pull the stick)...this is not possible, and here is when, if you enable controls vierwer by RCtrl+Enter, you will notice how the limit bars in the roll suddenly narrow to the center so showing you that the roll is limited now (even if you use the stick limiter disabler)...I don't know what is responsible for that, ACS or FBW?, but definetely something prevents the plane to do that mixing.

 

One thing I found to "somewhat" avoid this, is release the pressure of the stick and then try again the roll, it uses to work then to it's limits but the "mix" of both axes DURING a hard pull is limited unless you stop pulling for some reason.

 

thanks!!

[mytai01]

What you are missing is the fact that those planes have vectored thrust nozzles. The Su-33 does not. You will be limited to more basic maneuvers.

[Ironhand]

When I said "make a generous (high speed) pull and then try to roll the plane to achive a bank angle...YOU CAN'T!!!" I meant doing the roll AT THE SAME TIME (so mixing) as you make the pitch (pull the stick)...this is not possible, and here is when, if you enable controls vierwer by RCtrl+Enter, you will notice how the limit bars in the roll suddenly narrow to the center so showing you that the roll is limited now (even if you use the stick limiter disabler)...I don't know what is responsible for that, ACS or FBW?, but definetely something prevents the plane to do that mixing.

 

One thing I found to "somewhat" avoid this, is release the pressure of the stick and then try again the roll, it uses to work then to it's limits but the "mix" of both axes DURING a hard pull is limited unless you stop pulling for some reason.

 

thanks!!

Just checked in both the -27 and the -33 and am able to pitch and roll simultaneously in both. Fastest roll rate is in the 600-800 km/hr range for the -27 and seems similar for the -33. The rate becomes more constrained as speed/G increases to reduce strain on the fuselage tail section but I always have longitudinal and lateral authority. I see no sudden narrowing to the center on the controls viewer in either aircraft. So either I'm doing something very differently than you are or one of us has an installation issue.

[Ala12Rv-watermanpc]

Just checked in both the -27 and the -33 and am able to pitch and roll simultaneously in both. Fastest roll rate is in the 600-800 km/hr range for the -27 and seems similar for the -33. The rate becomes more constrained as speed/G increases to reduce strain on the fuselage tail section but I always have longitudinal and lateral authority. I see no sudden narrowing to the center on the controls viewer in either aircraft. So either I'm doing something very differently than you are or one of us has an installation issue.

 

Really?:huh:...I can confirm something is avoiding full roll rate/stick deflection when pulling some g's, I decided to take a couple of screens showing what I mean:

 

In this first one, there are no limits, as you can see all the stick deflection is available...the plane flies straight and leveled (btw, note how deviated are the center of the stick and the center of the control or zero trim, however my controls/axes are fine in the controls setup):

 

 

Now, this is what happens when I pull the stick, inmediately, the roll limits appear (note how the visual limits are closer to the center) and, while I have "some" roll margin, it's so small that basically is non existent, so the plane is "stuck" in the pull until I release the pressure in the stick or the speed is so low that basically the plane stalls:

 

 

I read some people had problems installing the module or the PFM mixed with the old one...none of these things seem to be happening to me...I used repair just in case, but all PMF seem to be working, the carrier, the behaviour of the plane is night and day, I can stall without seeing any scripting behaviour, etc. so I'm pretty sure the PFM is working correctly but just those damn limiters prevents the plane to be more maneuverable when near stall or post-stall maneuvers as I cant use full roll.

 

thanks for your help!!

 

EDIT: maybe you don't get those roll limits because you don't enabled the DCS...try doing this if you can, thanks!

Edited September 27, 2017 by watermanpc

[Fri13]

Or he would be happy with all that more jet to shoot at ;)

 

Only if the F-15 would be already in a firing position (when it wouldn't matter what the target does) or pilot doing the maneuver would do it in totally wrong time to make itself as a target when not being one at the moment (again, wouldn't matter who is targeting at him).

 

Maneuvers are not rules, there is no rules that you can just slap to scenario when you see one. This has been seen time after time in military aviation trainings that you can't learn to work like a machine "When the target does that, then do this and you win" but you need to be a creative, dynamic and continually observe and work the situation for your benefit.

 

It is only in the forums where "You can't use "Cobra" in real world as it is just for air shows" and "Speed is life!" are like black and white facts, while in reality they are far from it and just one positions of the whole scale of all possibilities. It is like a chess game in the air, the rules are very simple and easy to learn, but to apply them is where the skills comes to play, and doing even a foolish thought maneuver, can be a master move to win whole game.

 

In DCS multiplayer we can't do the most of the maneuvers as they don't either offer the benefit or are even required as all the other things in DCS are not there to affect them.

 

But for the OP, the aircraft does gain altitude slightly when doing the maneuver, but not really a much

as seen on the multiple videos in that with the vintage point to an a wingman. Looks like the aircraft gains altitude about 15-30m.

[Ironhand]

Really?:huh:...I can confirm something is avoiding full roll rate/stick deflection when pulling some g's, I decided to take a couple of screens showing what I mean:

 

In this first one, there are no limits, as you can see all the stick deflection is available...the plane flies straight and leveled (btw, note how deviated are the center of the stick and the center of the control or zero trim, however my controls/axes are fine in the controls setup):

 

...

 

Now, this is what happens when I pull the stick, inmediately, the roll limits appear (note how the visual limits are closer to the center) and, while I have "some" roll margin, it's so small that basically is non existent, so the plane is "stuck" in the pull until I release the pressure in the stick or the speed is so low that basically the plane stalls:

 

 

...

I think I might understand what you're referring to now. The only time I've ever seen that occur is when I've completely stalled the aircraft--for instance, when performing a tail slide. In both the -33 and -27 that normally does not happen, even during high-G maneuvering.

 

This is the Su-33 pit but it's the same in the Su-27. The maneuvering isn't crisp. It was early and I was still on my first cup of morning coffee:

 

 

FWIW, it's likely not an installation issue. I did a clean and repair on my end prior to the update and, like I mentioned, the behavior is identical in both the -33 and -27.

Edited September 27, 2017 by Ironhand

[GGTharos]

Maneuvers are not rules, there is no rules that you can just slap to scenario when you see one.

 

Yes there are.

 

This has been seen time after time in military aviation trainings that you can't learn to work like a machine "When the target does that, then do this and you win" but you need to be a creative, dynamic and continually observe and work the situation for your benefit.

 

Actually it is very much 'when the target does that, then you do this'. That is in fact exactly what is taught in military training. It is very complex and very dynamic, which is exactly why none of us flight sim pilots (or the vast majority of us, rather) would never qualify to be fighter pilots ... regardless of in game k/d.

 

In DCS multiplayer we can't do the most of the maneuvers as they don't either offer the benefit or are even required as all the other things in DCS are not there to affect them.

 

You can do 'all the maneuvers' and also 'reap all the benefits' ... but you have to do them at the appropriate time and in the correct context. People who reverse their turn in front of a bandit aren't going to be the ones to demonstrate any sort of advanced BFM skill since they can't get the most basic of basics down.

 

As with everything, there are rules of thumb:

Getting slow = doom

Cobra = doom

Reversing in front of your bandit = doom

 

That doesn't mean that you cannot use these maneuvers. What it really means is that you should really understand when and why you're going to use them.

But before you even go there, you should have a goo understanding of the very basics: Pursuit curves, turn circles, effects of starting parameters and throttle position on those, energy egg, altitude effects etc. I'm only covering the tip of the iceberg here.

 

TL;DR: Yes, BFM is like chess. There are rules for it, and they are taught in detail. All maneuvers have their place, but it doesn't mean you'll have much opportunity to use some of them.

[Ala12Rv-watermanpc]

I think I might understand what you're referring to now. The only time I've ever seen that occur is when I've completely stalled the aircraft--for instance, when performing a tail slide. In both the -33 and -27 that normally does not happen, even during high-G maneuvering.

 

This is the Su-33 pit but it's the same in the Su-27. The maneuvering isn't crisp. It was early and I was still on my first cup of morning coffee:

 

 

FWIW, it's likely not an installation issue. I did a clean and repair on my end prior to the update and, like I mentioned, the behavior is identical in both the -33 and -27.

 

Thanks a lot for your help and effort mate, really appreciated, and thanks also for the video :thumbup:

 

I think that maybe I was too late to edit my last post so you maybe didn't read the edit...it was important because I forgot to say that the roll limiter kicks in only if you are in DCS ("S" key) mode so that's why you usually don't experience it and you couldn't replicate in your video, sorry for that mate. Once the DCS is enabled, as soon as you make even not so big pulls, the limit will be there.

 

Another little question I have about the PFM is that I noticed that when enabling the DCS, there is a sudden BIG change in trim which could be even dangerous in certain situations, but what's more, how is possible that the 33 and the 27 behaves so differently to the activation of th DCS?, I mean, in the 27, enabling DCS leads to a hard, and I mean HARD sudden pitch DOWN, while in the 33 it leads to a hard pitch UP...would love to know why this sudden change in the pitch/trim when enabling DCS and why the different behaviour from 27 to 33 if possible.

 

 

thanks a lot!!:)

[GGTharos]

Just a guess:

 

It isn't the same airframe, and so the CG/CL relationship might be quite different, resulting in different base horizontal stab rigging ... just a WAG.

 

Another little question I have about the PFM is that I noticed that when enabling the DCS, there is a sudden BIG change in trim which could be even dangerous in certain situations, but what's more, how is possible that the 33 and the 27 behaves so differently to the activation of th DCS?, I mean, in the 27, enabling DCS leads to a hard, and I mean HARD sudden pitch DOWN, while in the 33 it leads to a hard pitch UP...would love to know why this sudden change in the pitch/trim when enabling DCS and why the different behaviour from 27 to 33 if possible.

[Ala12Rv-watermanpc]

Just a guess:

 

It isn't the same airframe, and so the CG/CL relationship might be quite different, resulting in different base horizontal stab rigging ... just a WAG.

 

Sure, I know they are not the same plane but it's not like an F-5 and an F-14, they share many things and the behaviour is in fact the OPPOSITE...anyway, the most interesting thing is WHY the sudden cjange in pitch happens when enabling DCS?

 

Another interesting thing I found about the "control system" in this thread about a russian su-27 pilot teaching an F-18 pilot the cobra:

 

 

We discussed the Cobra in our flight brief. It went something like this:

Me: "I would like you to show me the Cobra maneuver."

Kvochur: "Yes, sure."

Me: "What entry airspeed and altitude should we use?"

Kvochur extended the fingers of both hands in a calming gesture and said: "I show you."

That was it. I looked toward our interpreter for a read on this physical punctuation, but she returned the internationally universal shoulder shrug. So I took his brevity as an admonition against prying too much into this top-secret aerobatic phenomenon and made a mental note to be prepared to absorb as much technical data as I could during his demo.

When I was ready for the demo, he had me turn off the angle of attack limiter and another fly-by-wire switch that was never explained completely to me. Then he said, "I do one. We do one. You do one." The setup was 350 kilometers per hour (approximately 190 knots) in straight and level flight. He pulled the stick all the way back, and the airplane pitched nose up past vertical. In a little more than one second, we were more than 90 degrees nose up after the stick pull. He recovered the plane back to straight and level, and the maneuver was complete. The speed was about 90 knots as the nose approached the horizon. During the "We do one," I was again surprised at the non-aggressive control inputs. He used large pedal displacements during the first half of the pitch-up then transitioned to differential throttle control to keep the roll and yaw minimized. For the nose-down recovery, the stick was moved well forward but not all the way. Differential throttle that gave way to rudder-pedal activity essentially kept us wings-level throughout. My turn: I replicated what I had just ridden through, and the results were the same. I didn’t get past 90 degrees nose up like Kvochur, but I was awed anyway. Despite the radical attitude change, the entire maneuver was completed under 3G. Throughout this seemingly suicidal contortion, the engines never complained, and there was no implication of an impending loss of control.

Fun complete, I switched the limiter and fly-by-wire switches back to their normal positions, and we headed back.

 

This leads to ask myself if just using the DCS is "enough" when you want to make advanced post-stall maneuvers or if there is much more behind what RL pilots enable/disable to achive those meneuvers like that "angle of attack limiter" and the "FBW Off" switches.

[Ironhand]

...it was important because I forgot to say that the roll limiter kicks in only if you are in DCS ("S" key) mode so that's why you usually don't experience it and you couldn't replicate in your video, sorry for that mate. Once the DCS is enabled, as soon as you make even not so big pulls, the limit will be there.

I'll check it out in the AM, if I have time. I don't recall it being an issue in terms of flying but, then again, I tend to tread gingerly in direct control mode. Bad things happen, when you don't.

 

Another little question I have about the PFM is that I noticed that when enabling the DCS, there is a sudden BIG change in trim which could be even dangerous in certain situations, but what's more, how is possible that the 33 and the 27 behaves so differently to the activation of th DCS?, I mean, in the 27, enabling DCS leads to a hard, and I mean HARD sudden pitch DOWN, while in the 33 it leads to a hard pitch UP...would love to know why this sudden change in the pitch/trim when enabling DCS and why the different behaviour from 27 to 33 if possible.

Return trim to neutral before canceling (taking direct control of) the longitudinal channel which was translating the your trim inputs and most of that should disappear. The two will behave very similarly.

[Ironhand]

...I think that maybe I was too late to edit my last post so you maybe didn't read the edit...it was important because I forgot to say that the roll limiter kicks in only if you are in DCS ("S" key) mode so that's why you usually don't experience it and you couldn't replicate in your video, sorry for that mate. Once the DCS is enabled, as soon as you make even not so big pulls, the limit will be there...

Ahh... the devil's in the details. :) So I flew this morning in direct control mode and quickly realized that this is an AoA clamp of some sort. The stick pull has nothing to do with it beyond the fact that that is how you got yourself to an AoA of 25° or higher. As soon as you hit that angle, the clamp engages to apparently ensure that things don't get any worse.

 

At first, because I was following your instruction to pull and, then, try to roll, I thought it might be somehow tied to G loading. But pulling the stick and the subsequent G loadings were correlational and not causal. All that matters is the AoA:

 

 

The "clamp" engages at 25° AoA and disengages at 23°.

[GGTharos]

Can you disengage the AoA limiter?

[Ironhand]

Can you disengage the AoA limiter?

Assuming that means using the "Y" key, it makes no difference. The "clamp" remains. Which makes sense, I guess, since it's not there to limit the AoA. It's the roll component that it's limiting. Perhaps to limit your ability to stall one wing significantly before the other and put yourself on your back? DK.

 

BTW, never noticed it until this AM but the clamp is there in the -27, too.

 

EDIT: I guess thinking of it as an AoA clamp is a misrepresentation. It's actually an AoA roll clamp.

 

EDIT II: Now that I'm thinking about it, I bet you'd see the same clamping event even without direct control mode engaged as long as you push up to the 25° AoA mark. Didn't think to check that this morning.

Edited September 28, 2017 by Ironhand

[LJQCN101]

IRL Su-27 do have the roll stick limited to one third of full travel range above 25 deg, independent of Pitch FCS. This is to maximise your controllable AOA when rolling, according to the manual.

[Ala12Rv-watermanpc]

There you go Ironhand, that's exactly what I was refering to, great find :thumbup:...I'm not familiar with russian AC's so I didn't know well where to search the culprit but I see you are right about the AoA. I thought it was related to speed and/or G load as I would swear that when stalling in a vertical stop the "clamp" was removed but I might be wrong...and yes, all this also applies to the su-27.

 

Talking again about the "advanced maneuvers", I would like to point out that the reason I'm so interested in all this "control system" stuff is that maybe both the 27 and 33 would be much more maneuverable if we could disable some (all) of these systems, including the FBW which according to that russian pilot story I posted before seems to be possible in the real aircraft.

 

Anyway, that ROLL "clamp" is what is driving me crazy the most by far!:mad: but maybe there is no way to get rid of it or it would not be a good idea even if we look for maximum maneuverability...

 

thanks for your videos and help!:)

[Ironhand]

IRL Su-27 do have the roll stick limited to one third of full travel range above 25 deg, independent of Pitch FCS. This is to maximise your controllable AOA when rolling, according to the manual.

Thanks for that. The reasoning makes sense and the travel range limit in the sim seems about right. Are you referring to the real world manual (if so, can you reference the page?) or did I just miss it in the DCS manual?

 

 

...I...swear that when stalling in a vertical stop the "clamp" was removed but I might be wrong...

It well may have been removed--as soon as the AoA became less than 23°. In some of these maneuvers, how the air is actually flowing past the wings can surprise you.

 

...the reason I'm so interested in all this "control system" stuff is that maybe both the 27 and 33 would be much more maneuverable if we could disable some (all) of these systems, including the FBW which according to that russian pilot story I posted before seems to be possible in the real aircraft...

Unless I missed it, from my reading, he's referring to two switches. One is represented in the sim by the "Y" key (in the -33). The other could easily be the "S" key.

 

Anyway, that ROLL "clamp" is what is driving me crazy...maybe there is no way to get rid of it or it would not be a good idea even if we look for maximum maneuverability...

According to LJQCN101, it's there to keep you from putting yourself into a very bad situation. :)

 

Enjoy your flights and have fun pushing the envelope.