Impossible to fly for anyone else?

[pepin1234]

The -g blackout is correct. What might not be correct is the tendency of the aircraft to increase the -g by itself.

 

Right now is too much. that need to be tuning.

[GGTharos]

No, the sensitivity to -g is not too much. In RL if you take this much -g you're out of the fight, period. You're not going to be able to continue fighting, and you will definitely no longer be able to tolerate +g.

 

Since it isn't possible to simulate this in your head, your virtual pilot gets blacked out instead. It's a reasonable representation, even if you think it's unfair.

 

Here's a solution for you: Stop pulling -g, real fighter pilots avoid it as much as possible anyway.

 

Again, the Su-27 FM might have a problem with increasing the -g by itself to more than what you want it to be, I don't know - that's a question for Yo-Yo.

[Mr Whippy]

Yes I don't generally have a problem with the 'realism' of the flight model, it's the level to which the stability control lets you still enter that feedback loop zone which you'd probably never want to enter into... especially in a negative g case!

 

Stick kickback is a really valid real life way to stop pilots over-doing the inputs without really knowing about it, along with real g-forces.

 

So what do we use in a simulation?

 

 

I'd say if the real stick kicks back, then filter the I/O for a kickback. Make it happen in the visuals, make it happen to the simulation input.

OK there will be an inconsistency between user input and the aircraft input, but I'd prefer that temporarily than have the aircraft dead in the air.

 

 

 

But I think if this is a beta then it'll improve.

 

If we simulate the instability super accurately, but don't simulate the stability controls effectively too, then we're left with something that still isn't a complete simulation of the 27.

 

I bet the latter is just as hard, if not harder, than the former, to get right!

[Nedum]

Please look at 1:14:00 and 1:26:33

The Su27 has an Autolevel system and the accident the testpilot had, is the exact behavior we have now with the Su27 DCS modul but his accident was BEFORE the autolevel system was worked out and stops pilots for doing things those are not good!

At 1:26:33 they are talking about a automatic controll button (big red one on the stick)b. Ok they mean the autopilot button. You can switch off the automatic system (autopilot) and then trimm by yourself. But they are talking about a automated trim too.

I have the feeling we have the Su27 Testplane without any computer stabilisation. Or ED have overdone all those behaviors so the plane can do the Cobra maneuver? But where the hell is this automatic system they are talking all the time?

Or, at least, all those russian engineers in this vid do not know what they are talking about? :huh:

 

Fore sure, I can fly this plane, but this plane behaves like an Plane without any stabilisatiion automated system and with the "S" you can only switch from hard to "S"uper hard to fly.

Edited May 25, 2015 by Nedum

[pepin1234]

Please look at 1:14:00 and 1:26:33

The Su27 has an Autolevel system and the accident the testpilot had, is the exact behavior we have now with the Su27 DCS modul but his accident was BEFORE the autolevel system was worked out and stops pilots for doing things those are not good!

At 1:26:33 they are talking about a automatic controll button (big red one on the stick)b. Ok they mean the autopilot button. You can switch off the automatic system (autopilot) and then trimm by yourself. But they are talking about a automated trim too.

I have the feeling we have the Su27 Testplane without any computer stabilisation. Or ED have overdone all those behaviors so the plane can do the Cobra maneuver? But where the hell is this automatic system they are talking all the time?

Or, at least, all those russian engineers in this vid do not know what they are talking about? :huh:

 

Fore sure, I can fly this plane, but this plane behaves like an Plane without any stabilisatiion automated system and with the "S" you can only switch from hard to "S"uper hard to fly.

 

Where is your video. You forgot the link.

[GGTharos]

So what do we use in a simulation?

 

Sound, because that's all you can use.

 

I'd say if the real stick kicks back, then filter the I/O for a kickback.

 

No. How do you detect that the pilot 'pull through' then? I can fly fine without the game intervening in my inputs, thanks. It's your problem if you have to have the stick buried all the way back, all the time.

 

If we simulate the instability super accurately, but don't simulate the stability controls effectively too, then we're left with something that still isn't a complete simulation of the 27.

 

The stability FBW is simulated just fine in most cases. What's under-modeled is the meat-stick actuator ;)

[SharpeXB]

Hey all

 

So I picked up the SU-27 and...holy mother of christ, I know Sukhois are known for maneuverability but...I literally can't dogfight at any altitude or any airspeed, because the second I stop flying straight and level it just loses all semblance of control and stability.

 

Like, I'll twitch the stick, and it'll start doing all these crazy maneuvers, which inevitably puts me into an unrecoverable spin/stall, pilot blacks out/dies, and I crash. I know DCS is supposed to be all realistic and have realistic flight models, but...damn, man. How the hell am I supposed to dogfight in CQB if the second I roll/climb/do anything it just goes absolutely crazy? I mean...I figure if I have throttle set to full AB, and I'm already going 400 kts, a simple 3-4 G turn shouldn't make me stall out/lose control as if I'm trying to make that turn at 150 knots with throttle at zero. And yet that's what happens. It...actually kinda reminds me of what would happen in CFS3 if I had one damaged wing and pulled back on the stick, the plane woud auto-roll in the direction of the damaged wing.

 

I don't have this problem with the rest of the planes I have (F-15, SU-25, or A-10). Am I missing something?

I'm not experiencing anything odd flying the new Su-27. check your control assignments, with the update perhaps something got double assigned to your flight controls. I've had that happen with updates.

[Mowgli]

To be able to fly the Su-27 comfortably, one must master the art of trimming. The Su-27 reacts strongly to speed changes and generally (for me) requires a lot of nose down trim, but as your speed changes, where your trim needs to be changes alot more compared to say the F-15. But once you got the trim sorted she flies like a dream.

 

Actually like a wet dream - after flying the p-51 & Saber for a while I returned to FC3 and this time to the Flanker. learning it from the basics , flying at nights - each lesson per night. fell in love with this beauty - for the first time familiarizing how her body reacts to my touch with her new advanced flight model. yes she reacts gently and she is very responsive - trimming is the key.

 

I was a fan of the powerful Su-27. After this PFM I abandoned this bird. I find this is not the point for simulate the Su-27. I really hope this gone change someday for better.

 

read my description above - might be that your not mature enough?

[Mr Whippy]

Sound, because that's all you can use.

 

 

 

No. How do you detect that the pilot 'pull through' then? I can fly fine without the game intervening in my inputs, thanks. It's your problem if you have to have the stick buried all the way back, all the time.

 

 

 

The stability FBW is simulated just fine in most cases. What's under-modeled is the meat-stick actuator ;)

 

Do you fly with the stability control off?

 

Or are you relying on the stability control already?

 

If you are using stability control already, by definition you are letting the game intervene on your inputs. To a level determined by the setup of the stability control system.

 

The fact is the aircraft wouldn't even be safely flyable without input intervention.

 

OK my specific point is different about cutting input, but the spirit of the point is that you're already giving up all of your inputs to be processed.

 

 

 

So how is the stability control simulated? It sounds like you know it's simulated fine, so describe even in the simplest terms how it functions. LUT's, parametric type systems, single value limiters?

I get where you are coming from, but if you believe the current SU27 stability control is a perfect copy of reality then that is fine.

 

But I think many don't, ie, auto-trim. Why wouldn't you let the aircraft auto-trim? It has gyros and FBW, why not have a dead stick fly zero pitch/roll/yaw?

 

But as people have said it's beta so I'm happy to wait for it to get better to fly.

 

 

This aircraft should be easy to fly well, and hard to fly very well.

 

Right now it's just hard to fly well. Why make an aircraft hard to fly when it could be easy? What purpose does it serve a pilot, who over the years have been increasingly provided a lighter workload via technology.

 

 

 

 

PS, I flew one of the SU27 training missions (guns training) last night and the aircraft flew like a dream vs the quick-start missions.

 

Is the physics different, or is this just the difference between an empty vs loaded AC making it so much more unstable?

 

 

Thanks

 

Dave

[OnlyforDCS]

Use the search function Mr. Whippy. What you are asking has been explained numerous times, maybe GG will humour you but I doubt it.

 

The PFM is (mostly) correct. The FBW system is configured to have the aircraft behave as if it is a positively stable aircraft. In other words airspeed goes up, aircraft pitches up. Airspeed goes down aircraft pitches down.

 

This is how it is done in the real SU27, and yes it does make the pilot workload quite a little bit higher than you would find in modern western jets.

 

This is ALL the FBW system does, it produces artificial stability. "Artificial Stability" does not automatically mean the aircraft is easy to fly. Contrary to popular belief the Su27 is not a 'dream' to fly. It's not a Cesna and it's not an F15. The sooner people realize this, the sooner they can learn the ins and outs of the flight model and the sooner they can get proficient with it.

Edited May 29, 2015 by OnlyforDCS

[GGTharos]

Do you fly with the stability control off?

 

Or are you relying on the stability control already?

 

If you are using stability control already, by definition you are letting the game intervene on your inputs. To a level determined by the setup of the stability control system.

 

That's a huge simplification. No, the game is NOT intervening in my inputs, the simulation is shaping my inputs the way it is supposed to.

 

But it cannot provide feedback, so if it intervenes by countermanding what I'm doing via 'kicking' the virtual stick, now that's changing what I'm commanding the aircraft to do. In RL you simply have to overcome the force on the stick, so the pull will look smooth anyway. Why are you suggesting that the FBW should be bouncing my nose around instead?

 

OK my specific point is different about cutting input, but the spirit of the point is that you're already giving up all of your inputs to be processed.

Completely not the same thing. My inputs are processed but nothing in the RL FBW countermands your commands. You're suggesting that it does such a thing.

 

So how is the stability control simulated? It sounds like you know it's simulated fine, so describe even in the simplest terms how it functions. LUT's, parametric type systems, single value limiters?

I get where you are coming from, but if you believe the current SU27 stability control is a perfect copy of reality then that is fine.

I don't think it's a perfect copy because it relies on physical feedback to inform the pilot of some things. It's something that you can't get without a force-feedback stick.

 

But I think many don't, ie, auto-trim. Why wouldn't you let the aircraft auto-trim? It has gyros and FBW, why not have a dead stick fly zero pitch/roll/yaw?

Ask Sukhoi. It was their choice, in consultation with their air force pilots. There's really nothing that would prevent them from making this happen from a technology standpoint.

 

Right now it's just hard to fly well. Why make an aircraft hard to fly when it could be easy? What purpose does it serve a pilot, who over the years have been increasingly provided a lighter workload via technology.

Two things:

 

1) The FM is still beta-ish, but that's for Yo-Yo to answer. This means the physics may not be entirely correct, regardless of what the FBW is doing. The FBW may also require tweaking.

2) The workload IS decreased. Fly without stability augmentation and you'll fly yourself into bad situations much more often. The stability augmentation gives a fake positive stability behavior to the aircraft.

 

 

Is the physics different, or is this just the difference between an empty vs loaded AC making it so much more unstable?

A heavily loaded aircraft isn't necessarily less stable, you'll just reach unpleasant AoA values faster.

 

Certainly a heavy aircraft will and should behave differently. Payloads can change the center of gravity which can give rise to unwanted behaviors -for example on the F-15 hanging a centerline tank on it immediately makes it more susceptible to yaw departures and other effects. The difference might be subtle in some conditions/aircraft, huge in others.

 

In the end, it is up to you to gain the necessary knowledge about how aircraft fly and why, and then the necessary skill and finesse to control that aircraft.

[Drona]

Can any of the mods/testers get Yo-Yo to answer what parts of the flight model need to be tweaked (meaning what is currently wrong with the flight model, at least an acknowledgement of what is still left to be done with the flight model). It will just put to rest any further discussion/debate on this.

Edited May 29, 2015 by Kunz

[Ironhand]

...at least an acknowledgement of what is still left to be done with the flight model). It will just put to rest any further discussion/debate on this.

:) It might in some ways, Glen, but I doubt in all. One major complaint is that the system is set up to mimic an aircraft with positive speed stability. As your speed goes up or down, so does your nose. This means you have to trim. Since it's written right into the manual as the added airspeed trimming law, the only way I can see this changing is if they discover they've been misinformed all this time. Most probably that isn't the case.

 

If you read what the manual has to say and check out the diagram, you'll realize that the basic underlying system is designed to mimic an aircraft which is neutrally stable. The direction you point yourself in will be the direction you continue to go, even as your speed increases or decreases (and this is what many of those complaining are expecting to experience). It's that added airspeed trimming law that makes the difference. The law is there to make sure that the AoA you set remains more or less the same as your speed increases or decreases. This is how the aircraft's designers wanted it to behave.

 

Some of the above might still be subject to tweaking but, like I said, I doubt there will be any wholesale changes--at least it won't be completely scrapped. Personally I think it needs tweaking but that's based on nothing but uninformed intuition. It just feels like it overreacts.

Edited May 29, 2015 by Ironhand

[Drona]

the only way I can see this changing is if they discover they've been misinformed all this time. Most probably that isn't the case.

 

Given how secretive a military can be, I have my doubts, but I guess ED knows better since they probably have SMEs. I would still be nice if Yo-Yo can comment on this.

 

Some of the above might still be subject to tweaking but, like I said, I doubt there will be any wholesale changes--at least it won't be completely scrapped. Personally I think it needs tweaking but that's based on nothing but uninformed intuition. It just feels like it overreacts.

 

I feel the same way, it just overreacts way too much.

[Ironhand]

Given how secretive a military can be, I have my doubts, but I guess ED knows better since they probably have SMEs. I would still be nice if Yo-Yo can comment on this...

While he hasn't commented on what needs tweaking, he has commented on several aspects/concepts that people are having difficulty accepting and/or understanding. Just use the Advanced Search function in this forum and search for "Yo-Yo" as the poster. Leave everything else blank. A number of hits will pop up.

 

 

I feel the same way, it just overreacts way too much.

Maybe yes, maybe no. I feel that it reacts to severely but, then again, given the goal of the trimming law, I'm not sure there would be any point in having it react more slowly or to a reduced degree. It's the broad and rapid variations in airspeed that make it problematic. But it's most useful as your speed decreases, especially as you approach the low end of the speed range. So I wonder if there's not some airspeed damping of the law that should be coming into play at higher airspeeds. Again, this is based on nothing but supposition.

[Rapidfire]

While he hasn't commented on what needs tweaking, he has commented on several aspects/concepts that people are having difficulty accepting and/or understanding. Just use the Advanced Search function in this forum and search for "Yo-Yo" as the poster. Leave everything else blank. A number of hits will pop up.

 

 

 

Maybe yes, maybe no. I feel that it reacts to severely but, then again, given the goal of the trimming law, I'm not sure there would be any point in having it react more slowly or to a reduced degree. It's the broad and rapid variations in airspeed that make it problematic. But it's most useful as your speed decreases, especially as you approach the low end of the speed range. So I wonder if there's not some airspeed damping of the law that should be coming into play at higher airspeeds. Again, this is based on nothing but supposition.

I think for military purposes they don't make them very realistic to save for top secrete information. :thumbup:

[karambiatos]

 

Maybe yes, maybe no. I feel that it reacts to severely but, then again, given the goal of the trimming law, I'm not sure there would be any point in having it react more slowly or to a reduced degree. It's the broad and rapid variations in airspeed that make it problematic. But it's most useful as your speed decreases, especially as you approach the low end of the speed range. So I wonder if there's not some airspeed damping of the law that should be coming into play at higher airspeeds. Again, this is based on nothing but supposition.

 

The trim system in the FC3 aircraft isn't accurate enough (maybe the whole sim) you can never trim the aircraft nicely, it's pretty much always going up or down, and god forbid you trim for roll.

 

One thing that needs tweaking are the autopilots, currently they'll lead to your death, and also once you disengage the autopilots and reset trim the 27s sometimes get stuck in a constant slow roll.

[Ironhand]

The trim system in the FC3 aircraft isn't accurate enough (maybe the whole sim) you can never trim the aircraft nicely, it's pretty much always going up or down, ...

That's because your speed is always going up and down. Anytime I can settle into a constant airspeed, I can actually go get a cup of coffee and come back to find myself within a 100 meters or so of my original altitude. But, again, that's only once my airspeed has been dialed in. If you are merely close, then your flight path will resemble a slowly decreasing sinusoidal curve as the aircraft attempts to match your airspeed to the AoA you asked for.

 

One thing that needs tweaking are the autopilots, currently they'll lead to your death, and also once you disengage the autopilots and reset trim the 27s sometimes get stuck in a constant slow roll.

Haven't really bothered with them yet. I rarely used them in the past, except for demonstration, and haven't had reason to use them in the present. I do understand, though, that they can give you quite a ride on some occasions.

[karambiatos]

That's because your speed is always going up and down. Anytime I can settle into a constant airspeed, I can actually go get a cup of coffee and come back to find myself within a 100 meters or so of my original altitude. But, again, that's only once my airspeed has been dialed in. If you are merely close, then your flight path will resemble a slowly decreasing sinusoidal curve as the aircraft attempts to match your airspeed to the AoA you asked for.

At constant speed obviously.

[Ironhand]

At constant speed obviously.

:) Obviously. Perhaps another way to think about this is that this additional airspeed trimming law tries to maintain the same AoA and, consequently, airspeed while, without it, the underlying FBW system would try to maintain the same lift.

[karambiatos]

:) Obviously. Perhaps another way to think about this is that this additional airspeed trimming law tries to maintain the same AoA and, consequently, airspeed while, without it, the underlying FBW system would try to maintain the same lift.

Could be, but the trimming being a bit wonky, isn't exclusive to the 27, the F-15 also suffers from trim weirdness.

[Ironhand]

Could be, but the trimming being a bit wonky, isn't exclusive to the 27, the F-15 also suffers from trim weirdness.

I didn't think you were supposed to trim the F-15. Shows how little time I have in its cockpit.

 

As far as our lovely Flanker is concerned, I don't try to trim for absolutely level flight, anyway. I just want it close enough that 1) I can have a light touch on the stick and 2) if I get distracted in the pit for a minute, I won't find the aircraft in an extreme attitude, when I look up again.

[GGTharos]

You're not supposed to trim the F-15.

 

Actually that's not entirely true:

 

1) Roll due to asymmtery is not trimmed out automatically

2) The PTC doesn't have enough authority to handle an altitude transition of 40000'

3) The PTC WILL 'wind up', so you have to correct (with the stick, not with trim) after a hard turn or a long turn until the PTC catches up.

 

I didn't think you were supposed to trim the F-15. Shows how little time I have in its cockpit.

 

As far as our lovely Flanker is concerned, I don't try to trim for absolutely level flight, anyway. I just want it close enough that 1) I can have a light touch on the stick and 2) if I get distracted in the pit for a minute, I won't find the aircraft in an extreme attitude, when I look up again.

[DarkFire]

In relation to the trimmer on the Su-27, how realistic is the rate of change of trim? I wonder because even the slightest input appears to produce a very significant change. I think it could be a bit easier to trim if the rate of change wasn't quite so wild. That is, unless the trimmer behaviour as modelled is realistic...?

 

Having a more gentle trimmer would certainly make fine adjustment a lot easier.

[GGTharos]

I haven't used the trim on a Su-27 so I don't really know, but I suspect that you're correct and that it's too coarse.

 

Of course, once more here we lack physical feedback: In RL, when you trim, you hold the stick where you want the plane to be flying and use the trim to 'zero the force' so you can fly hands off. You'll feel the resistance diminishing, so trimming is much easier in a real jet from that perspective.

 

That's just my interpretation though.