Think I might finally understand Trim problem!

If you are seeing stick jerk, you are probably having trim jump issue, and not AP issue.

Whatever I'm having, it makes it unusable. I've made a short video, on the ground straight after start-up had finished, showing how it jerks when I click trim. This was done with Central Trimmer mode off but I tested with it on and it was the same. I'm not sure what it's doing but it seems to be doubling up my input when I press Trim (and I was pressing T on the keyboard for this test). It doesn't appear as bad in the second half of the video but that's because I was trying to see if I could literally let go of the stick and let it re-centre the very instant I pressed Trim and I was probably actually letting go of the stick a split-second before, so that it was moving back towards the centre when Trim actually registered.

These are my current settings from mods\aircrafts\KA-50\FM\FMOptions.lua:

----------- for new helicopter trimmer method -----------------------------------------------
----------- (joystick will be disable after trim until it come to neutral zone) -------------
HelicopterTrimmerZonePitch		= 0.2
HelicopterTrimmerZoneRoll		= 0.2	
HelicopterTrimmerZoneRudder		= 0.4

---------- for old helicopter trimmer method ------------------------------------------------
----------- (aperiodic process)  ------------------------------------------------------------
HelicopterTrimmerTauInverse		= 4.5 --lower value - decrease trim speed after trim button release. 

I lowered HelicopterTrimmerTauInverse from 7.0 to 4.5 to give me more time to center the stick so I don't believe it can still be so short that it's registering the stick position twice in the split-second after clicking Trim. I increased the zones for the new method too but when I tested with Central Trimmer mode on, I moved the stick much further than in the video and it still did the same thing, so I don't think it can be that I'm moving the stick within the zone.

Even if either mode was working properly though, I still think it would work better if stick movements away from the centre were still registered after clicking Trim (which would emulate the real behaviour, where after the pilot clicks Trim he can still move the stick further and click Trim again (or not), without any timeout or having to re-center the stick) but stick movements towards the centre were ignored until the stick had re-centered, which would allow us to release the stick, as is necessary when using a non-FFB stick as we can't hold it in position all the time, without any unwanted input.

This would eliminate any problem of double-input which can happen with the original trimmer method, as it will never go "OK, time's up, hmm stick's forward, you must have re-centered it and moved it forward again so I'll pitch forward some more" and whilst there might be times when we want to make adjustments towards the center and won't be able to until we've re-centered the stick, at least we'll be able to make give additional input away from the center without re-centering, which we can't do now.

Another option could be to have a "ignore stick" button, so that when we want to let go of the stick and let it re-center we hold that and the rest of the time the virtual stick tracks the real one, which would allow us to fly much more like the real thing.

If you have a stick, which centers very precisely, you should try using center based trim method and lowering activation zones. Using Warthog I can still manage to trim with 0.01. That shrinks "double input" the zone around the center by large margin.

Also, is FFB disabled in your setup? It was important thing to do for non FFB stick in previous versions (at least) as it interfered with trimming.

Interesting thread.

 

Along the same lines, I was wondering -- what is the best curvature and deadzone settings for the Ka-50, considering the twitchiness of trimming the AP. I am using a X52 HOTAS.

 

Thanks.

There is no "best curvature", it's about personal preferences. For example I use 15, somebody might like 0, somebody 25... Try different values and you will see what suits you best.

If you have a stick, which centers very precisely, you should try using center based trim method and lowering activation zones. Using Warthog I can still manage to trim with 0.01. That shrinks "double input" the zone around the center by large margin.

 

Also, is FFB disabled in your setup? It was important thing to do for non FFB stick in previous versions (at least) as it interfered with trimming.

Yeah, FFB is disabled.

By setting the zones to a tenth of what they were, i.e. 0.02, 0.02 and 0.04, I can finally use the Central Trimmer mode without the shark diving all over the place :)

I still don't get why the other method isn't working though, as with HelicopterTrimmerTauInverse = 4.5 it should give me enough time to re-center the stick but it seems to be acting as if the timer runs out as soon as I click Trim and thus entering the input twice.

I found there's one advantage with Central Trimmer mode though, as after clicking Trim if I keep the stick in the same position I can keep clicking Trim to add extra input. I guess this is similar to how the real Shark works, in that the pilot doesn't have to center the stick if he wants to bank/pitch further and trim again and with the old method I guess this isn't possible as the stick has to be centered before the timer runs out, otherwise it's position will be added to the input again, even if it hasn't moved and trim hasn't been clicked.

I'm not sure I understand how the real Shark works though. Let's say the whole range of the stick=100. If the pilot moves the stick forward 20 and clicks Trim, it will stay in that position. If he clicks (and releases) Trim again without moving the stick, will that add another 20 to the input or does it treat the Trim position as center, so if he wanted to pitch forward a further 20, he'd have to move the stick to 40 and click Trim?

In the real shark, the trimmer button just controls where the stick is centered. So per your example, if the pilot moves the stick forward 20 and clicks trim, the stick will stay at 20 forward. If the pilot then clicks and releases trim without moving the stick again, nothing happens. The stick simply remains centered where it was before which means the attitude of the shark is exactly the same as it was before. This is why a FFB stick is great when flying because it simply works the same way as the real stick.

In the real shark, the trimmer button just controls where the stick is centered. So per your example, if the pilot moves the stick forward 20 and clicks trim, the stick will stay at 20 forward. If the pilot then clicks and releases trim without moving the stick again, nothing happens. The stick simply remains centered where it was before which means the attitude of the shark is exactly the same as it was before. This is why a FFB stick is great when flying because it simply works the same way as the real stick.

...and on the release, it assigns the attitude, which is held by autopilot. Maybe stick possition is the same, but attitude of the helo might change due to wind, IAS change, collective input etc.

OK, thanks for clarifying how the real Shark works guys.

It seems the behaviour in Central Trimmer mode is wrong then, as if I hold the stick in the same position and click Trim again it's adding extra input again, so I think we need a different method like I suggested, either where movement away from center is still registered but not towards center until the stick is re-centered or all movement is registered except when holding the "ignore stick" button to let us release/re-center it.

OK, thanks for clarifying how the real Shark works guys.

 

It seems the behaviour in Central Trimmer mode is wrong then, as if I hold the stick in the same position and click Trim again it's adding extra input again, so I think we need a different method like I suggested, either where movement away from center is still registered but not towards center until the stick is re-centered or all movement is registered except when holding the "ignore stick" button to let us release/re-center it.

The reason for central trimmer mode to work the way it does is to try and closely match that of the real shark. In the real shark, you press the trim button and the cyclic is then centered in that position. This means if you take your hand off the cyclic then, it stays in that position. With a non FFB stick, you press the trim button, the virtual stick is now centered in that position, but your physical joystick is not centered. This is why all input is disabled until you center your physical stick because your physical stick and the in game stick are no longer in sync. Once you move your stick back to center, it now is in sync again with the stick in game. As pointed out, this extra movement back to center is not present in the real shark but its the best compromise for using a non-FFB.

The reason for central trimmer mode to work the way it does is to try and closely match that of the real shark. In the real shark, you press the trim button and the cyclic is then centered in that position. This means if you take your hand off the cyclic then, it stays in that position. With a non FFB stick, you press the trim button, the virtual stick is now centered in that position, but your physical joystick is not centered. This is why all input is disabled until you center your physical stick because your physical stick and the in game stick are no longer in sync. Once you move your stick back to center, it now is in sync again with the stick in game. As pointed out, this extra movement back to center is not present in the real shark but its the best compromise for using a non-FFB.

Yeah but I'm saying that central trimmer mode fails to emulate the real shark closely at all because as you say, in the real shark clicking Trim fixes the stick in that position but the pilot can still move it and click Trim again (or not) but in BS2 we can't use the stick until we've re-centered it first which makes it very awkward and unnatural. I disagree that it's the best compromise and think one of my suggestions would work better.

I guess the main goal of the central trim position is to have your stick centered when the virtual stick is centered. The whole goal of trim is to make it so you can fly with your hand off the stick. In the real shark when a pilot trims to a position, the stick becomes centered there. The pilot can then move the stick around however they want but when they let go of the stick it goes back to that trimmed position. With our joysticks when you let go they always go back to the center, not where we trimmed. Forcing the user to go back to center makes it so your joystick matches the joystick in the cockpit.

With your suggested methods, say you trim to a position but don't center the stick. You then keep moving the stick and may even trim again. How will this movement register? Will it be according to the center of your joystick or the center of the in game cyclic according to your trim? These have now become 2 different things because you have not centered the stick.

For example, you trim 10 forward. Then, while still holding 10 forward, you move 5 left. Now you are 10 forward and 5 left of the center of your stick. However, you are only 5 left of the trim position. Which input do you then use? Having a key to press that says ignore stick input could work and let you center the stick. But what happens if you don't center it but rather move somewhere else? The stick suddenly jumps somewhere and center may no longer be center. Eventually, one must center the stick and somehow tell the game that it is centered and matches the in game trimmed position.

I guess the main goal of the central trim position is to have your stick centered when the virtual stick is centered. The whole goal of trim is to make it so you can fly with your hand off the stick. In the real shark when a pilot trims to a position, the stick becomes centered there. The pilot can then move the stick around however they want but when they let go of the stick it goes back to that trimmed position. With our joysticks when you let go they always go back to the center, not where we trimmed. Forcing the user to go back to center makes it so your joystick matches the joystick in the cockpit.

 

With your suggested methods, say you trim to a position but don't center the stick. You then keep moving the stick and may even trim again. How will this movement register? Will it be according to the center of your joystick or the center of the in game cyclic according to your trim? These have now become 2 different things because you have not centered the stick.

 

For example, you trim 10 forward. Then, while still holding 10 forward, you move 5 left. Now you are 10 forward and 5 left of the center of your stick. However, you are only 5 left of the trim position. Which input do you then use? Having a key to press that says ignore stick input could work and let you center the stick. But what happens if you don't center it but rather move somewhere else? The stick suddenly jumps somewhere and center may no longer be center. Eventually, one must center the stick and somehow tell the game that it is centered and matches the in game trimmed position.

That's the thing though, as the virtual stick isn't centered when it's trimmed to a position, it would probably be more accurate to say it's zeroed at that position, so having my real stick centered doesn't match the virtual stick at all. For instance, if the virtual stick is trimmed at forward 50 making that it's new zero, it can then only move a further 50. With my stick centered, it can move forward 100 from the centre, which the virtual stick can't match. I presume it ignores the input after 50, when the virtual stick is at 100, the end of it's physical range.

As for my alternative suggestions, the movement would register as it would in the real Shark, i.e. from the current position, so if the stick is trimmed to forward 50 and then the pilot moves it a further 10, it would put the virtual stick at 60. I don't really understand your question about moving it 5 left when it's trimmed to 10 forward, as 5 left from 10 forward gives the same result as 5 left from 0 forward. The idea with the "ignore stick" key is so that you can release the stick and let it re-center itself, which is necessary so that we don't have to hold our non-FFB sticks in position permanently. I don't see how it could move somewhere else other than center when doing this or somehow cause center to no longer be center. Perhaps the "ignore stick" key would work best if it had a fairly long time-out, so e.g. for 3s after pressing it the stick input is ignored, so even if the pilot is a bit slow in releasing the stick it will be certain to be at center by the time the 3s runs out. Generally when using this it will be when the pilot is happy with the trimmed position and wants to leave the stick alone for a while, so I don't see it being a problem having a longish timeout.

I think we are just looking at this from different angles. You are looking at simming the realism of trim in that when you trim in the real shark you can then keep moving the stick and trimming, no unnecessary movements. I'm looking at it from the angle of when you trim the shark in real life, you immediately no longer have to put pressure on the stick to maintain that position. Rather, that position has become the "center" of the stick. Both are equally valid things to simulate and truly the best way of doing it in the sim is to simply have a FFB stick. However, options are rather limited there.

I think it would be cool if ED came up with another method of controlling trim with a non-FFB stick that would give players the option to choose what they like. Unfortunately, this is probably way down on their scope of things to do.

Yeah, I guess that ED chose to simulate the "no longer have to put pressure on the stick" thing. Hopefully they'll see this thread and consider adding an alternative method.

consider adding an alternative method.

There's already two methods?? Central On or Central Off

There's already two methods?? Central On or Central Off

Yes I know and I don't like either of them as they both require me to re-center my stick every time I click Trim.

Yes I know and I don't like either of them as they both require me to re-center my stick every time I click Trim.

Sorry Doveman, I mean I can't think of any other implementation "scheme" to get beyond the fact that you wouldn't have a FFB stick. Suggestions?

Just another technique of using the current systems:

Recently I've adopted to using flight director for major changes in direction or when beyond the forward edge of battle(aka I know i'm going to be yanking and banking). Then turn FD off only if I need to maintain a slight hover, this way my trimming is relegated to small adjustments.

Sorry Doveman, I mean I can't think of any other implementation "scheme" to get beyond the fact that you wouldn't have a FFB stick. Suggestions?

I made a couple of suggestions in my previous posts.

Just another technique of using the current systems:

Recently I've adopted to using flight director for major changes in direction or when beyond the forward edge of battle(aka I know i'm going to be yanking and banking). Then turn FD off only if I need to maintain a slight hover, this way my trimming is relegated to small adjustments.

Holding trim button on non-FFB stick is like flying with FD on.

Let's say you are driving a hypothetical vehicle, which has brakes, accelerator pedal and AP for speed control. You accelerate to 30km/h and tell AP to stabilize that speed. Stabilization means that if you release accelerator a bit, AP will rev engine up a bit by itself, and if you add a bit of accelerator, AP will rev engine down and/or apply some brakes, so that speed will remain 30km/h. Now, if you add lots of accelerator, AP will be overwhelmed as it does hot have the same authority, and despite it trying to rev down and brake, vehicle will still accelerate to 50km/h. So, you are driving at 50km/h fighting AP and winning, but suddenly you realize that you want AP to stabilize the speed at 50km/h. You press the button, and upon doing that you first get AP input (its effort to brake you down to 30km/h) disabled, and then get it memorize the new speed setting (50km/h) on button release. What happens? Vehicle jumps forward at first and easily reaches 60km/h (past the new target speed of 50km/h), because of the delay between disabling AP and enabling it again. "Aggressiveness" of that speed jump depends on the difference between how quickly AP is able to remove its input and how quickly it can reach max of its input. Keep in mind that AP does not care about accelerator or brake pedals. It only cares about speed of hypothetical vehicle, and not about position of brake and accelerator pedals. If we introduced trim system to our vehicle, then that system would care about these positions, but AP would still care only about speed. Overspeed happens in this example not because of presence of AP input, but because of lack (or sudden removal) of that input.

The question is that this system seems to be great to keep the blackshark in its current flight parameters but introduces extra workload to the pilot when manouvering.

I note no-one who insisted that Trim is working fine could be bothered to watch my tracks I posted

Comments like these don't really make me feel like I want to help you but I'll let it pass as "lost in internet translation".

Re: youtube video, just to confirm you are only pressing T on the keyboard to induce the stick movement on the ground?

I'll see if I can be "bothered" to take a look at your tracks on tuesday

Also, I misread how you wanted to implement trim. I see now that you want to be able to hold the stick forward and still continue to trim additional input. While your "center stick button" or "nullify stick input button" idea seems logical, as noted by others I do not think the 50 is going to get much if any attention from ed besides compatibility updates. Besides the ability to rapidly tap additional input with a stick held forward(for example) into the trim, what benefit would I get from using your method? Why could I not get this same input solution via press and hold trimming? FD On, or recenter trimming?

May be I'm using trim in a different approach then you are, which makes me not see the need. Again, if I'm aggressively maneuvering FD goes on, and trim isn't even necessary(well almost...). Then I'll FD trim to a semi stable attitude and turn FD off, at which point i'm trimmed pretty well, or will only need slight retrimming, via tap recenter, but both methods "work" on my pc i just prefer the recenter.

My point was there are two trim methods, which are valid ways of getting the helicopter to let you fly hands free.

FFB stick and assuming the bugs are fixed in the next patch then you don't have to worry about the physical stick not matching the virtual...

edit: can you confirm the situation happens without the blue cockpit?

That's what I tried to explain with my ignored example. When manouvering with AP on pilot inputs are exagerated compared to the same manouvers without AP. This exageration shows up when the trim button is down.

 

The question is that this system seems to be great to keep the blackshark in its current flight parameters but introduces extra workload to the pilot when manouvering.

Check IRL cockpit videos. They drive it like they've stole it. Jumping all over the place.

Check IRL cockpit videos. They drive it like they've stole it. Jumping all over the place.

Referring to this guy?

(not saying it is on with 100% certainty but) how do you know FD isn't on? "No hud indication". I'd say can't tell either way because the hud is different from ours (attitude indicator is "upside down").

Doveman,

I was able to duplicate the tap T to make the virtual joystick move without input while on the ground video only after I dropped my deadzone on my joystick to 0. I usually have

Deadzone 5

Sat 100

Sat 100

Curve 20

on both x and y

Which makes me think the issue is a recentering issue more than need a new trim method ;unless you want the "hold the stick foward to continue to add trim values", at which point I'd say you'd be better off with FFB.

Use the old centering method, and re center stick and rudder each time you release trim = win

You fly straight and level with the helicopter compensated, the stick (or spring FFB) is anchored or centered, and coincides with the attitude memorized by the AP. Right.

You enter a small change in attitude, and then you try to compensate, what happens is that the helicopter "jumps" from the attitude memorized by the AP to the position of the stick.

That is the only problem, no matter spring or FFB.

I attached another video, a short flight, compensate different attitudes. Note well in 00:45, which induce this effect, there is only a slight variation on the stick, but does not match the stored in the AP, and the helicopter falls nose down.

In the rest of the flight the helicopter remains perfectly stable to compensate.

Greetings!

Re: youtube video, just to confirm you are only pressing T on the keyboard to induce the stick movement on the ground?

Yes, I just used the keyboard T to ensure I wasn't nudging the stick.

I'll see if I can be "bothered" to take a look at your tracks on tuesday

Thanks.

Also, I misread how you wanted to implement trim. I see now that you want to be able to hold the stick forward and still continue to trim additional input. While your "center stick button" or "nullify stick input button" idea seems logical, as noted by others I do not think the 50 is going to get much if any attention from ed besides compatibility updates. Besides the ability to rapidly tap additional input with a stick held forward(for example) into the trim, what benefit would I get from using your method? Why could I not get this same input solution via press and hold trimming? FD On, or recenter trimming?

I'm just thinking that in RL the pilot has the ability to do this, i.e. click Trim then make a small adjustment and click it again and with the current methods which require us to recentre between each click we don't. It's obviously pretty much impossible to get the stick back from centre to exactly where it was when you last clicked Trim, so it's likely that the next time you click it, it will be quite a way off from the first click.

May be I'm using trim in a different approach then you are, which makes me not see the need. Again, if I'm aggressively maneuvering FD goes on, and trim isn't even necessary(well almost...). Then I'll FD trim to a semi stable attitude and turn FD off, at which point i'm trimmed pretty well, or will only need slight retrimming, via tap recenter, but both methods "work" on my pc i just prefer the recenter.

Sure, when aggressively maneuvering trim isn't really needed (I tend to use the hold-Trim method for that rather than engage FD, mainly because when I need to do so it's because I'm being targeted and I don't have time to fiddle around with my mouse to click on FD. I need to try and remember to toggle it on with my voice control software though). It's more when stopping such maneuvering and wanting to stabilise or just in general flight that the first click of trim might not get it exactly where I want it (particularly with the oversteer problem) and it'd be useful to be able to adjust the Trim without having to recentre the stick in-between.

edit: can you confirm the situation happens without the blue cockpit?

I think so but I'll re-test without that.