KA50 Target Designator "a bad JOKE"

[Havner]

Just enabling FFB=on in the options doesn't do the ... hrm, "trick"?

 

I just tested it.

 

EDIT: scrap what I wrote previously. Enabling FFB in options with non-FFB stick changes nothing.

Edited May 23, 2014 by Havner

[karambiatos]

Does anyone know a way to make the game think you have a FFB stick even if you don't have one? To "switch" the sim into FFB mode. Not to require to recenter after trim, etc. I know I'd have to keep the stick in the proper center position by myself (no servomotors) but at least I'd be able to compare the behaviour, cause it seems we won't get any meaningful track from a FFB owner anytime soon.

 

EDIT: E.g. creating some virtual USB device connected to a physical one (like ppjoy used to do) and make it introduce itself as MSFFB2.

 

what i think the sim does is turn the virtual trim off, and just use the stick inputs, so you can turn the trim off in the sim easily, but youll need a way to keep the stick where you want it.

[ShuRugal]

Afaik, the discussion in this thread is already beyond that ... (especially it was agreed upon that the AP does not move the stick, neither in DCS nor in RL - swash plate and stick do not always correspond to each other)

 

 

I fail to see how the AP could not move the stick IRL. If the AP had 20% (it's authority) control independent of the cyclic, and the hydraulics went out, the cyclic stick would suddenly have 20% free-play in all directions. While it is not impossible for someone to design a system that worked this way, it would be uncharistically stupid for a company otherwise noted for its brilliant engineering.

 

I can't seem to find it now, but there was a diagram floating around a few years back (could have sworn it was in the manual) detailing the linkages in the KA-50, and clearly showing that the hydraulic assist was parallel to the primary control linkages.

 

It's been a while since i watched for it specifically, but I know for certain that pre-World BS1 and BS2 you could watch the stick in the cyclic move on its own in Route mode, and I have seen videos on these forums demonstrating this effect with a FFB sick as well.

[AlphaOneSix]

If the AP had 20% (it's authority) control independent of the cyclic, and the hydraulics went out, the cyclic stick would suddenly have 20% free-play in all directions. While it is not impossible for someone to design a system that worked this way, it would be uncharistically stupid for a company otherwise noted for its brilliant engineering.

 

Ouch, straight up calling Kamov designers stupid. You're also calling just about every other helicopter designer stupid, as this also works similarly for Sikorsky, Bell, and Eurocopter. You should contact them all ASAP to tell them how stupid they are.

 

But I digress, you're misunderstanding several concepts, including how hydraulic flight controls work in a helicopter, as well as how stability augmentation systems work in helicopters.

[Flagrum]

I fail to see how the AP could not move the stick IRL. If the AP had 20% (it's authority) control independent of the cyclic, and the hydraulics went out, the cyclic stick would suddenly have 20% free-play in all directions. While it is not impossible for someone to design a system that worked this way, it would be uncharistically stupid for a company otherwise noted for its brilliant engineering.

 

I can't seem to find it now, but there was a diagram floating around a few years back (could have sworn it was in the manual) detailing the linkages in the KA-50, and clearly showing that the hydraulic assist was parallel to the primary control linkages.

 

It's been a while since i watched for it specifically, but I know for certain that pre-World BS1 and BS2 you could watch the stick in the cyclic move on its own in Route mode, and I have seen videos on these forums demonstrating this effect with a FFB sick as well.

I admit, the way you describe sound more intuitive. But why the engineers designed against it and instead did what they actually did - what the pros and cons are - I am unable to judge. But I bet, there are good reasons for it. :o)

If you ever stumble upon such a video showing that behaviour, post it. I never saw one ... and I watched quite a few of BS vids. ;o)

[ShuRugal]

I still don't think it can work any other way. Kill the hydraulics, and the helicopter remains flyable. If the ap control box were between the stick and swash, it would be impossible to fly.

[Flagrum]

I still don't think it can work any other way. Kill the hydraulics, and the helicopter remains flyable. If the ap control box were between the stick and swash, it would be impossible to fly.

Why should it be impossible (genuine question)?

 

Also to consider (fwiw): the AP is not between stick and swash plate, it is parallel to the stick. It adds (positive or negative) steering input to that of the stick, it does not "translate" the input.

[ShuRugal]

Alright, consider a control linkage:

 

When the pilot moves his stick, the mechanical linkage pushes or pulls on the swashplate, producing control output:

 

 

 

If we add a hydraulic assist system and let the autopilot have some command over it....

 

then when the AP pushes the controls, the pilot's controls, being mechanically linked, will also move:

 

Unless something breaks:

 

Now, we could design an AP system that would move without the pilot's control also moving (IE: behave like a non FFB stick in the sim). It would have the control linkage from the pilot interrupted with a hydraulic actuator:

 

This way, the AP can move the swash independent of pilot input:

 

The problem with this, is that if there is no hydraulic pressure, then now the pilot moves his stick, and until he has moved it further than the travel of that actuator, nothing happens to the swashplate:

 

And the inverse would be true as well: with such a system, if the hydraulics failed, the pilot could hold his stick manually in exactly the correct position to maintain stable flight (a hover, say) and the helicopter would be all over the place, because every gust of wind acting on the rotors would push the controls back and forth the full throw that the AP actuators have, and the pilot would only feel it through the stick when they ran out of travel.

[Havner]

Asking again. Does the in cockpit stick (as well as joystick) move in the sim with FFB joystick (e.g. In the Route mode). Cause your explanation makes sense only if it does and I think it has been established that it doesn't.

[ShuRugal]

I know for a fact that it did in BS1, I don't think it does in World, but so much has been broken since World got rolled, that is hardly an indicator of anything.

[AlphaOneSix]

In the Ka-50, the autopilot inputs are not translated back to the pilot's controls. If they did in BS1 for FFB, then that was a bug.

 

Also, in helicopters with hydraulic boosters, the boosters are non-reversible. That is, they can only move when acted on by the pilot's controls or the autopilot, movements of the swashplate cannot travel back down the flight controls.

[Bushmanni]

The problem with this, is that if there is no hydraulic pressure, then now the pilot moves his stick, and until he has moved it further than the travel of that actuator, nothing happens to the swashplate:

 

It's actually possible to design a hydraulic cylinder so that it centers itself and locks up when pressure is lost.

[AlphaOneSix]

The Ka-50 hydraulic boosters can be operated without hydraulics, but it is very difficult. You would not be able to fly without hydraulics. The autopilot is also inoperative without hydraulics.

[Havner]

Going back to the subject we still don't know whether there is a dive with FFB joystick or not. Or whether there should be. If the stick doesn't move with the AP there should be.

[AlphaOneSix]

The stick does not move with autopilot input. Or at least, it should not. The flight controls in the Ka-50 cockpit will not move unless the pilot moves them.

 

This is different from some AP systems on other aircraft where SAS/SCAS only has a very small amount of control authority (2-5%) and acts without any feedback to the pilot's controls in the cockpit, while trim servos have full control authority (100%) and when they move the controls, it DOES move the controls in the cockpit. The Ka-50 and Mi-8 don't have this (well, older Mi-8's with the RA-60B directional control servo does, but that's only in the yaw channel). In the Ka-50 and Mi-8, the autopilot system for SAS (stability augmentation) and the system for attitude, heading, and altitude hold all go through the servo, which has only 20% control authority.

 

Some newer Mi-8 versions (only special-built ones, I don't think they are standard) do have trim servos and an autopilot with 100% control authority, but those trim servos are drop-in replacements for the magnetic brake and trim feel spring assemblies, and are completely separate from the hydraulic boosters, which still have their 20% control authority for SAS functions.

[ShuRugal]

In the Ka-50, the autopilot inputs are not translated back to the pilot's controls. If they did in BS1 for FFB, then that was a bug.

 

Also, in helicopters with hydraulic boosters, the boosters are non-reversible. That is, they can only move when acted on by the pilot's controls or the autopilot, movements of the swashplate cannot travel back down the flight controls.

 

I would be very interested to know how this is achieved. I am genuinely curious how a mechanical linkage can be made to transmit forces in only one direction while still functioning.

 

 

It's actually possible to design a hydraulic cylinder so that it centers itself and locks up when pressure is lost.

 

this does make much better sense, for the behaviour seen in the sim.

[AlphaOneSix]

With hydraulic pressure applied to the hydraulic booster, it is, for all intents and purposes, in a permanent state of hydraulic lock and can't move at all. When the control rod from the pilot's controls move, a shuttle valve inside the booster is displaced. Depending on the direction of this displacement, hydraulic fluid under pressure is allowed to enter one of two chambers within the booster, while simultaneously, fluid from the other chamber is allowed to return to the hydraulic fluid reservoir. The autopilot has its own shuttle valve, but acts in a similar fashion.

[ShuRugal]

With hydraulic pressure applied to the hydraulic booster, it is, for all intents and purposes, in a permanent state of hydraulic lock and can't move at all. When the control rod from the pilot's controls move, a shuttle valve inside the booster is displaced. Depending on the direction of this displacement, hydraulic fluid under pressure is allowed to enter one of two chambers within the booster, while simultaneously, fluid from the other chamber is allowed to return to the hydraulic fluid reservoir. The autopilot has its own shuttle valve, but acts in a similar fashion.

 

okay, lemme see if i understand this correctly..

 

The actuator for the booster lies in-line with the control linkage. The actuator is supplied pressure and locked into a position. when pilot moves the stick, it operates the spool of a 4-way valve to operate the actuator, and the whole thing moves as a unit. The AP has it's own 4-way which operates the same actuator, allowing the controls to move without pilot input. presumably, there is a fail-safe as Busmanni described which locks the actuator in center of travel in the event of hydraulic failure.

 

Have i got it right? in this way, the AP can operate without disturbing the pilot controls, but still maintains control integrity in the event of hydraulic failure?

[AlphaOneSix]

If the hydraulics fail, the autopilot system shuts off. It requires hydraulic system pressure to operate (in the case of the Mi-8, it must be the primary system, the backup system cannot operate the autopilot).

 

Also, the actuator goes into "manual" mode and, in theory at least, is able to be manipulated without hydraulic power. In practice, this requires so much force that it's not practical. In the Mi-8, the emergency procedure for a dual hydraulic system failure is to prepare the crew for bailout. For example, I am able to operate the pedals on an Mi-8 without hydraulic pressure, but it's not easy. I can also operate the cyclic if I brace myself and use both arms. Of course, I cannot operate either fast enough to effectively fly the aircraft (note that I've never tried in the air, obviously, just on the ground).

 

I'll try to find a digram I have of the actuators, although my diagrams are for a KAU-115 model booster from the Mi-8MTV-5 and newer aircraft. I believe that the Ka-50 uses a KAU-100, but I'm not positive. I don't know the specific differences between the Mi-8 actuators and the Ka-50 actuators.

[ShuRugal]

so, what it boils down to, is that behaviour in the sim after hydraulic failure is unrealistic, because under real condition, you could never hope to continue flying the helicopter in such a state.

 

Which brings us back to another old problem: why does the KA-50 have dual hydraulics if they always fail together? If one takes battle damage and fails, the other immediately begins loosing pressure and fails moments later. They don't cross-feed at all, do they?

[marrow]

Regarding the question whether FFB and non-FFB behaves differently when trimming after a radical stick movement: it doesn't. You will get a bump in both cases.

 

But since you can spam trimmer with FFB it's not a problem. Just trim, trim and trim all the time while maneuvering and there won't be big changes between trims and no bumps. Also bumps are easier to fix with trimmer spamming.

 

Press and hold is another method that I used with non-FFB, but with FFB I don't like it since the stick goes limp while the trimmer is held down.

[Havner]

Regarding the question whether FFB and non-FFB behaves differently when trimming after a radical stick movement: it doesn't. You will get a bump in both cases.

 

That's what I'd assume. Thanks.

 

Still would be nice to see that on a track as a proof. Cause different people claim differently.

 

But since you can spam trimmer with FFB it's not a problem. Just trim, trim and trim all the time while maneuvering and there won't be big changes between trims and no bumps. Also bumps are easier to fix with trimmer spamming.

 

True as well.

 

EDIT: To sum up, if what marrow wrote is correct (and I assumed it is since the very beginning):

 

If you'd take a FFB joystick and remove it's servomotors (make it completely loose) and take non-FFB joystick and remove its spring (make it completely loose as well) there is only one difference in how the game handles those 2 joysticks. After you release the trimmer you have to recenter the non-FFB stick and the virtual center is shifted by the negative joy deflection at the moment of trimmer release. With FFB joystick you don't have to recenter.

 

That is (and should be) the only difference.

 

About the AP, it's logically applied "after" the stick (without getting into hydraulics and technical details). It can move the swashplate within 20% of its authority without moving the cyclic (either 3D in-cockpit one or physical FFB one). It tries to "go back" to the remembered state if you move the cyclic without the trimmer hence the bump.

 

The bump is not a bug. The reason for it is as I initially explained, suddenly releasing the current AP authority:

http://forums.eagle.ru/showpost.php?p=2071011&postcount=52

 

With FFB stick you can spam click because if you do it often (as marrow very well pointed out) you simply reset the AP very often and you don't have to fight with it. This is not possible with non-FFB stick not because there is a bug in DCS Ka-50, but because you'd have to recenter the stick after every click which is simply not practical (it wouldn't be spamming anymore cause you'd be limited by your re-centering abilities).

Edited May 25, 2014 by Havner

[AlphaOneSix]

so, what it boils down to, is that behaviour in the sim after hydraulic failure is unrealistic, because under real condition, you could never hope to continue flying the helicopter in such a state.

 

That is correct.

 

Which brings us back to another old problem: why does the KA-50 have dual hydraulics if they always fail together? If one takes battle damage and fails, the other immediately begins loosing pressure and fails moments later. They don't cross-feed at all, do they?

 

I don't know how the Ka-50 hydraulics work specifically. On the Mi-8, all the hydraulic equipment is colocated, so in the event of a mechanical failure, the other system takes over, no problem. However, it is not very resistant to battle damage. In other words, for the Mi-8, battle damage that causes one hydraulic system to fail has a decent chance of causing them both to fail.

 

Maybe the Ka-50 suffers from a similar issue? I don't know.

 

I will point out that lots of helicopters with dual (or even triple) hydraulic systems have several places where damage could cause all of them to fail. It really just depends on the nature of the damage.

 

It would be nice, however, if on occasion one of the hydraulic systems would continue to work on the Ka-50. ;)

[Migow]

That is correct.

 

 

 

I don't know how the Ka-50 hydraulics work specifically. On the Mi-8, all the hydraulic equipment is colocated, so in the event of a mechanical failure, the other system takes over, no problem. However, it is not very resistant to battle damage. In other words, for the Mi-8, battle damage that causes one hydraulic system to fail has a decent chance of causing them both to fail.

 

Maybe the Ka-50 suffers from a similar issue? I don't know.

 

I will point out that lots of helicopters with dual (or even triple) hydraulic systems have several places where damage could cause all of them to fail. It really just depends on the nature of the damage.

 

It would be nice, however, if on occasion one of the hydraulic systems would continue to work on the Ka-50. ;)

 

ka50 's main hydraulic is armored , (against 12.7 and 20 mm fragment?)

 

in dcs when we lose the main and common hydraulic we can still fly even 5 min after hydro loss( i think it should be impossible)

Edited May 25, 2014 by Fifou265

[doveman]

The bump is not a bug. The reason for it is as I initially explained, suddenly releasing the current AP authority:

http://forums.eagle.ru/showpost.php?p=2071011&postcount=52

 

With FFB stick you can spam click because if you do it often (as marrow very well pointed out) you simply reset the AP very often and you don't have to fight with it. This is not possible with non-FFB stick not because there is a bug in DCS Ka-50, but because you'd have to recenter the stick after every click which is simply not practical (it wouldn't be spamming anymore cause you'd be limited by your re-centering abilities).

 

Well assuming that's all correct, I'd still consider it a bug if it's not possible to fly the KA-50 properly (by which I mean the Russian click-release method, I don't like using the click-hold method) with a non-FFB stick, which an awful lot of people have.

 

I've suggested some methods that might fix this problem before, to enable non-FFB users to rapidly click-release without having to recenter the stick, such as having a button to hold which makes the sim ignore the stick, so after we've finished trimming and are in steady flight and want to be able to let go of the stick, we hold this button, release the stick to center and then release the button and the physical stick would be centered whilst the virtual one is trimmed where we left it.

 

Or after clicking trim, treat the current physical stick position as input 0, so that it doesn't add anything more if we don't centre it, then only recognise further movement away from the centre but ignore movement back towards it, as generally when trimming you're meant to bank/pitch a little and trim, then a bit more, trim, etc until you get to where you want it, so you'd do that then release the stick to centre.

 

Maybe they're not the best solutions and ED can come up with something better but I feel they could do something like this if they were interested in non-FFB users being able to fly the Shark.

 

I almost got a FFB2 but the e-bay seller turned out to be a joker who didn't send the stick or any messages and after I opened a case, said he'd been busy with a new job, miscalculated the postage (now he reckoned it was going to cost twice as much as every other FFB2 seller is charging to post it) and asked for some more money. I told him to get lost and give me a refund, which he did at least but it means I'm stuck with my non-FFB stick for now.