Here is a way to turn off heading-hold

[cow_art]

Disclaimer1: I realize this might not work for all input devices, but it works well for pedals without springs.

For anyone who is annoyed with the current, overzealous heading hold of the Apache: I figured out a simple way to temporarily turn it off, without deactivating the yaw SAS channel or editing LUA files:

- While on the ground (or in active pause)

- Push pedal all the way to the right

- Klick the Force Trim Release (FTR)

- Bring pedal back to a reasonable position and wait 1-2 seconds for the SAS to settle

The heading hold is now off and will remain off as long as you don't touch the FTR again. It will no longer "help" you hold a heading, but the yaw SAS will still provide damping and help countering torque. And, surprisingly, the Apache becomes a lot more intuitive for me. The SAS no longer violently opposes small heading corrections at slow speed. Suddenly the Apache is just a regular old helicopter doing regular helicopter things.

As a bonus, this doesn't even break the other hold modes: if you trim the cyclic correctly you can for example still use  the ATT position hold submode, but now you can easily do tiny heading corrections without fighting the system.

Disclaimer2: I know this is not a realistic way to use the Apache and real pilots will probably facepalm at this suggestion. I am sure, the SAS will get tuned at some point. But for now I really like the Apache's handling a lot better this way. I have a lot more fun flying it and thought I would share.

 

 

Edited April 22, 2023 by cow_art
fixed typos

[Tepnox]

Actually quite good tip. I was wondering why sometimes the SAS heading-hold is active when taking off and sometimes it is off when taking off - despite having the paddles in the same spot. Quite irregular behavior right now of the SAS.

This should help build up some muscle memory for the pedal-usage when SAS is no longer interfering with the take-off-procedure.

Thx, will give it a try until ED fixes this awful SAS behavior.

Edited April 27, 2023 by Tepnox

[Floyd1212]

On 4/22/2023 at 2:43 AM, cow_art said:

The heading hold is now off and will remain off as long as you don't touch the FTR again.

So this means you aren't using FTR again for the rest of your flight?  Meaning you aren't able to take your hand off the cyclic to do something in the cockpit?

Have you tried holding the FTR while making your small pedal adjustments?  As long as you are holding FTR, the SAS will not "fight" against your inputs.

[cow_art]

16 hours ago, Floyd1212 said:

So this means you aren't using FTR again for the rest of your flight?  Meaning you aren't able to take your hand off the cyclic to do something in the cockpit?

Well, my joystick is springless and has dry clutches, so it pretty much stays where I put it. So that's a non-issue for me

But to answer your question: No, actually I currently use the FTR a lot. Heading hold works well in many situations (namely, when I actually WANT it to hold a heading). In these situations I klick the FTR a lot to update the reference position. But every once in a while heading hold starts to get on my nerves (usually when I am slow and want more fine control). I now have a simple way to temporarily turn it off (I mostly play single player and can just do active pause ON, pedal right, klick FTR, pedal back to original position, active pause OFF, enjoy helicopter without heading hold for a bit).

Quote

Have you tried holding the FTR while making your small pedal adjustments?  As long as you are holding FTR, the SAS will not "fight" against your inputs.

Sure, that works and I am fairly decent at this. But holding the FTR completely disables the SAS including ATT hold. Very often I dont want that and it makes things more complicated than they need to be. I just want heading hold to go away, I don't want to sacrifice all stability assistance.

Edited April 28, 2023 by cow_art

[Sandman1330]

On 4/27/2023 at 8:55 AM, Floyd1212 said:

Have you tried holding the FTR while making your small pedal adjustments?  As long as you are holding FTR, the SAS will not "fight" against your inputs.

This is the way.

In fact, that's how I do all maneuvering. I depress and hold the FTR, set the aircraft attitude, then release the FTR. This ensures your SAS channels are always centered and avoids SAS saturated situations.

It's a bit tougher in the hover as it does disable (actually reduces) roll/pitch assistance, but you just need to get used to that. Spend some time just hovering with FTR depressed, get good hovering that way and you'll be rock solid when you start using FTR (and therefore SAS) again.

[GremlinIV]

Do you guys get a right yaw while in the hover and trimming your stick with a quick trim click.  Watching the controls indicator when you click FTR the heading hold goes off then back on and during that i get some yaw and maybe some other stuff because of that yaw, like scas on the stick or collective or both - it creates a wobble you have to work to stay in a good static hover - annoying....

[cow_art]

15 hours ago, GremlinIV said:

Do you guys get a right yaw while in the hover and trimming your stick with a quick trim click.  Watching the controls indicator when you click FTR the heading hold goes off then back on and during that i get some yaw and maybe some other stuff because of that yaw, like scas on the stick or collective or both - it creates a wobble you have to work to stay in a good static hover - annoying....

Yes I also get that. Heading hold gets turned off when you click the FTR and if your pedal position was not perfect the yaw corrections from the SAS also go away for a moment. It makes the nose jerk to one side (depending on the pedal correction of the SAS). It's quite noticable. No idea if its realistic or not, but it's definitely there (and I also find it annoying)

[GremlinIV]

Thank god, Thought maybe i was the only one at the party in Fancy dress.... ( I came dressed a an early Native American, hoping not to be left out)

This maybe why when i nose down to move off and start trimming the cyclic in small bumps, there is a fight on.  Lots of parameters changing on the way like torque, altitude, speed, transition, trim, and this bit of unwanted motion upsetting all those, creating more necessary control inputs, creating more instability, creating more scas,..... you can see where im going with this.... ultimately the heading hold does go off at around 25 30 knots

Is this an expected Control Loop process in the real world helo, or a DCS WIPism...

I have said in other posts about the scas leading your input, if you use the "move control, bump trim and centre" method for inputs... is this then the wrong way to do it?

My guess is holding the FTR will still turn it off and back on while you move stick and release, and if the scas dont agree, your gonna get the yaw movement plus other stuff even more..

I need to do some more testing, but right off i cant see how you can exactly match the Controls indicator, which in real world you dont have..

In my defence, and as always I am not knocking anything or anyone, just trying to progress my flying abilities.. and highlight my experiences with the module.

Edited April 29, 2023 by GremlinIV

[Sandman1330]

So, one of the Apache pilots would have to chime in for the Apache specifically, but I can tell you how I fly the 412 in real life. It has similar force trim and SAS / SCAS systems, though a touch less advanced than the Apache.

In the 412, I hold the FTR any time I am moving the controls. In straight and level flight, FTR is released and I let the SAS do its job. Anytime I adjust the aircraft attitude, I depress and hold FTR, set the aircraft attitude, and release FTR. This ensures the APIs (as they are called on the 412) always start out centered.

In the 412, if you push against FTR you are also pushing against the SAS, and it fights you. Then you end up with autotrim failures (same idea as SAS saturated).

I have tried this in the DCS Apache, and it seems the most effective way to control the aircraft without getting those unwanted movements. It doesn’t work perfectly as the center trimmer in DCS doesn’t work the same so you can still get a bit of jumping around when you release trim. You have to train yourself to recenter the stick immediately after releasing trim, and/or make very small inputs at a time. It’s a bit wonky.

So, how does this translate in game then? An example. On picking up to hover, I am holding the FTR as I pull light on wheels, and into the pickup. Once stable(ish) in hover, release FTR and let SCAS help. Your stick will be trimmed to near hover position, your yaw SCAS channel will be centered, and SCAS will help stabilize you in hover. This is the key to avoid attitude “jumping” when you depress FTR and the channels center, especially in yaw. You can even activate auto hover at this point. A minor adjustment to this technique is to hold FTR until light on wheels, then release it for the pickup. Now yaw SCAS will be near centered and SCAS will help you through the pick up.

Now to transition to forward flight, I depress and hold FTR, set the accelerating attitude I want, stabilize there then release FTR. Now again everything is centered, trim is set for forward flight, and I can engage att mode or keep flying manually with minor adjustments to controls, with or without FTR depressed depending on how minor the adjustment.

Decelerating back to hover is the hard part because of the self centering stick and FTR implementation in DCS. Now you pull the cyclic back to decelerate, but can only get as far back as centered because of your trim position. I am working on the muscle memory to initiate the decel with FTR depressed, release FTR and center the stick, then quickly reset trim and continue. It’s a bit wonky and not very realistic but without a proper non-centering stick it’s a challenge.

Anyway, I hope this essay helps. Ultimately it’s all a challenge because most of us aren’t working with proper sticks. I’ve played both with no springs and with springs, both have downsides. No spring means you can’t ever take your hand off the cyclic, can’t use att/hover modes, etc. With a human CPG I like this, as he can do most of the comms, nav input, etc. With George I have to do all that and fly, so I’ve settled on using a sprung stick. One day maybe I’ll buy a fancy base with dry clutches to get as close as possible to reality….

Edited April 29, 2023 by Sandman1330

[Floyd1212]

With the current progress of the module, FTR is not working as it should be.

I am not a SME, but from what I gather from other posts, when you press and hold FTR the system is supposed to continue to assist in keeping the helo stable, but relax the way it fights back at your inputs so you can make minor adjustments.  However, in its current state, it appears to completely disable any assist, and the aircraft gets super wobbly in all axis, all at once. 

You can see in the Controls Indicator for as long as you are holding FTR, the red and green marks follow your controls 1:1, and as soon as you release FTR the green mark starts to deviate again and apply inputs in an attempt to keep the aircraft at a stable heading.  If the system were working as intended, you should still see the green marks working to stabilize the aircraft while FTR is held, though not as aggressively.

I personally use the tap method, but not frequently.  I will trim when I am in a hover (and use the ATT and ALT Hold modes as needed), then when I am ready to get moving again I won't trim again until I am in stable flight with the flight path vector where I want it, then tap FTR and relax my stick to center.  When I am transitioning back to a hover, or coming in to land, I use the Force Trim Reset command to zero out my controls and manually come to a hover or land.

I look forward to the day when I can hold the FTR and have it not get completely squirrely, but for now I will keep using the occasional tap method. 

 

[Floyd1212]

24 minutes ago, Sandman1330 said:

Decelerating back to hover is the hard part because of the self centering stick and FTR implementation in DCS. Now you pull the cyclic back to decelerate, but can only get as far back as centered because of your trim position. I am working on the muscle memory to initiate the decel with FTR depressed, release FTR and center the stick, then quickly reset trim and continue. It’s a bit wonky and not very realistic but without a proper non-centering stick it’s a challenge.

To me, this was the biggest compromise to make with a sprung cyclic.  I never liked the idea of having to "unwind" the trim you have built up in order to get back to a zero state.  Seems counter intuitive, and not at all what you do in a real helo (as you know).

I came up with a solution using Joystick Gremlin to temporarily "disconnect" the signals from my cyclic to be able to use Force Trim Reset for a smooth transition back to a zero-trim state.  I'll link to it here as it has been a while, and there are probably some new Apache pilots that might find it useful.

 

[Sandman1330]

5 minutes ago, Floyd1212 said:

To me, this was the biggest compromise to make with a sprung cyclic.  I never liked the idea of having to "unwind" the trim you have built up in order to get back to a zero state.  Seems counter intuitive, and not at all what you do in a real helo (as you know).

I came up with a solution using Joystick Gremlin to temporarily "disconnect" the signals from my cyclic to be able to use Force Trim Reset for a smooth transition back to a zero-trim state.  I'll link to it here as it has been a while, and there are probably some new Apache pilots that might find it useful.

 

That’s rather ingenious, I may have to give that a try, thanks!

19 minutes ago, Floyd1212 said:

With the current progress of the module, FTR is not working as it should be.

I am not a SME, but from what I gather from other posts, when you press and hold FTR the system is supposed to continue to assist in keeping the helo stable, but relax the way it fights back at your inputs so you can make minor adjustments.  However, in its current state, it appears to completely disable any assist, and the aircraft gets super wobbly in all axis, all at once. 

You can see in the Controls Indicator for as long as you are holding FTR, the red and green marks follow your controls 1:1, and as soon as you release FTR the green mark starts to deviate again and apply inputs in an attempt to keep the aircraft at a stable heading.  If the system were working as intended, you should still see the green marks working to stabilize the aircraft while FTR is held, though not as aggressively.

I personally use the tap method, but not frequently.  I will trim when I am in a hover (and use the ATT and ALT Hold modes as needed), then when I am ready to get moving again I won't trim again until I am in stable flight with the flight path vector where I want it, then tap FTR and relax my stick to center.  When I am transitioning back to a hover, or coming in to land, I use the Force Trim Reset command to zero out my controls and manually come to a hover or land.

I look forward to the day when I can hold the FTR and have it not get completely squirrely, but for now I will keep using the occasional tap method. 

 

Your understanding is how the 412 works. There is a big difference between hovering with FTR depressed and hovering with the autopilots turned completely off.

The DCS Apache feels like hovering autopilots off right now when you hold FTR. Again not sure Apache specific, but your understanding is correct for the 412 and would seem logical for the Apache.

If this does get fixed / implemented down the road, holding FTR down as I described above will definitely be the way!

[Raptor9]

49 minutes ago, Floyd1212 said:

I am not a SME, but from what I gather from other posts, when you press and hold FTR the system is supposed to continue to assist in keeping the helo stable, but relax the way it fights back at your inputs so you can make minor adjustments.  However, in its current state, it appears to completely disable any assist, and the aircraft gets super wobbly in all axis, all at once. 

You can see in the Controls Indicator for as long as you are holding FTR, the red and green marks follow your controls 1:1, and as soon as you release FTR the green mark starts to deviate again and apply inputs in an attempt to keep the aircraft at a stable heading.  If the system were working as intended, you should still see the green marks working to stabilize the aircraft while FTR is held, though not as aggressively.

Yes and no. This may have been caused by previous posts from myself that weren't as explicit as they should be (differentiating between SAS sleeves and SAS logic), coupled with a personal misunderstanding of the green indicator marks and what they represent.

To start off, the green indicator marks are not a direct indicator of the positions of each SAS sleeve within the flight control servos (that's what I thought they were at first as well). The green indicators represent the real-time positions of the swashplates on each rotor system in each respective axis. So they may serve as an indirect indication as to what the SAS sleeves are doing within each flight control servo, but they don't represent the SAS sleeves themselves. For example, if the green line in the yaw axis is to the left of the white line, then I can see the tail rotor swashplate has been moved an additional amount by the SAS sleeve in the Directional servo.

When the force trim is not being pressed, rate damping is in play, which can be detected by the swashplate (green cross) moving independently of the cyclic position (white diamond). When force trim is pressed, the rate damping is removed, which causes the FMC to keep the swashplate aligned with the control positions. To do this, the FMC uses the SAS sleeve positions to remove any mechanical lag in the system to ensure the swashplate is perfectly synced with the controls (part of the CAS logic in the FMC). So in this instance, while the force trim is pressed, the SAS sleeves are still active, but they are only performing CAS functions. So the SAS sleeves themselves do move a little while the force trim is pressed, but only to remove the mechanical lag in the system as part of the CAS logic; not rate damping, which is a SAS logic.

What is still work-in-progress is 1) the CAS logic when the force trim is not pressed, causing some swashplate overshoot when a significant input is applied, 2) the swashplate behavior when the FMC channels are turned off, no mechanical lag applied yet, and 3) the overall stability of the aircraft itself, which is why the aircraft is wobbly when the force trim is pressed. (There are other aspects of the flight model, SCAS, and hold modes that are still work-in-progress as well, but these are the three relevant points in this case)

[Floyd1212]

Ah, thanks for the correction.

So, I can still hope to use the FTR hold method in the future, not because there will be more rate damping in play when FTR is held, but because the helo in general will be more stable when there is no rate damping being applied?

I'll keep doing what I am doing until that day comes, then reset my brain to relearn how to use FTR properly.

[GremlinIV]

So say we all...

Now lets jump over to the Huey thread and push that Love we were promised..

I might buy a collective if we get these 2 right..

Edited April 29, 2023 by GremlinIV

[Raptor9]

36 minutes ago, Floyd1212 said:

So, I can still hope to use the FTR hold method in the future, not because there will be more rate damping in play when FTR is held, but because the helo in general will be more stable when there is no rate damping being applied?

I'll keep doing what I am doing until that day comes, then reset my brain to relearn how to use FTR properly.

Yes. In the end, fly the aircraft how it works best for you.

However, the reason that myself or BradMick keep harping on using the force trim more is because the hold modes are only effective when employed after the helicopter is properly trimmed (stable attitude, SAS sleeves centered after several seconds of holding the force trim). If the hold modes are applied with the SAS sleeves biased to one side or the other, it is limiting the authority for the hold modes to operate, which may lead to oscillations or a SAS SATURATE message/tone. But this can also lead to the excursions some are describing when they press the force trim or disengage the hold modes. (Not to mention that the hold modes won't even engage if the controls are not returned to their force trim reference positions anyway)

If I am heavily reliant on the hold modes to keep myself in a stable hover, that means the SAS sleeves are biased to one side simply to keep the aircraft in a stable attitude. As soon as I press the force trim or disengage the hold mode, then yes, those SAS sleeves are going to start working back to center as they should. The issue isn't the hold modes or the SAS sleeve logic, the issue is that the aircraft wasn't set into a stable hover to begin with. If I get the aircraft into a hover myself, so that I am only applying a slight and occasional pressure here and there against the cyclic to maintain the hover, when I engage the Position Hold, all I am doing is telling the hold mode to do those small corrections for me. If I disengage the hold mode (whether that be by turning it off or by pressing the force trim to interrupt it), the SAS sleeves will return to center, but they would only move a very small amount because the aircraft is already trimmed for and in a stable hover.

So the issue isn't that the hold modes or the SAS sleeves are making the pilot's job harder, it's that the pilot is making the pilot's job harder. This is not a criticism on anyone's abilities. Flying helicopters is difficult; even before you add on all the other tasks of navigation, radios, sensors, weapons, making tactical decisions, getting shot at, etc. Future improvements to the flight model will of course help with the predictability of the aircraft, but the underlying logic of how the force trim interacts with the SAS sleeves won't really change. It takes practice, there is no way around it. Heck, when the DCS Black Shark first came out, even as a professional helicopter pilot I struggled to understand its flight computer and autopilot systems. But once I learned the underlying logic behind its automation, it became a joy to fly. We'll get there with the DCS AH-64D.

[Sandman1330]

4 hours ago, Raptor9 said:

Yes and no. This may have been caused by previous posts from myself that weren't as explicit as they should be (differentiating between SAS sleeves and SAS logic), coupled with a personal misunderstanding of the green indicator marks and what they represent.

To start off, the green indicator marks are not a direct indicator of the positions of each SAS sleeve within the flight control servos (that's what I thought they were at first as well). The green indicators represent the real-time positions of the swashplates on each rotor system in each respective axis. So they may serve as an indirect indication as to what the SAS sleeves are doing within each flight control servo, but they don't represent the SAS sleeves themselves. For example, if the green line in the yaw axis is to the left of the white line, then I can see the tail rotor swashplate has been moved an additional amount by the SAS sleeve in the Directional servo.

When the force trim is not being pressed, rate damping is in play, which can be detected by the swashplate (green cross) moving independently of the cyclic position (white diamond). When force trim is pressed, the rate damping is removed, which causes the FMC to keep the swashplate aligned with the control positions. To do this, the FMC uses the SAS sleeve positions to remove any mechanical lag in the system to ensure the swashplate is perfectly synced with the controls (part of the CAS logic in the FMC). So in this instance, while the force trim is pressed, the SAS sleeves are still active, but they are only performing CAS functions. So the SAS sleeves themselves do move a little while the force trim is pressed, but only to remove the mechanical lag in the system as part of the CAS logic; not rate damping, which is a SAS logic.

What is still work-in-progress is 1) the CAS logic when the force trim is not pressed, causing some swashplate overshoot when a significant input is applied, 2) the swashplate behavior when the FMC channels are turned off, no mechanical lag applied yet, and 3) the overall stability of the aircraft itself, which is why the aircraft is wobbly when the force trim is pressed. (There are other aspects of the flight model, SCAS, and hold modes that are still work-in-progress as well, but these are the three relevant points in this case)

 

3 hours ago, Raptor9 said:

Yes. In the end, fly the aircraft how it works best for you.

However, the reason that myself or BradMick keep harping on using the force trim more is because the hold modes are only effective when employed after the helicopter is properly trimmed (stable attitude, SAS sleeves centered after several seconds of holding the force trim). If the hold modes are applied with the SAS sleeves biased to one side or the other, it is limiting the authority for the hold modes to operate, which may lead to oscillations or a SAS SATURATE message/tone. But this can also lead to the excursions some are describing when they press the force trim or disengage the hold modes. (Not to mention that the hold modes won't even engage if the controls are not returned to their force trim reference positions anyway)

If I am heavily reliant on the hold modes to keep myself in a stable hover, that means the SAS sleeves are biased to one side simply to keep the aircraft in a stable attitude. As soon as I press the force trim or disengage the hold mode, then yes, those SAS sleeves are going to start working back to center as they should. The issue isn't the hold modes or the SAS sleeve logic, the issue is that the aircraft wasn't set into a stable hover to begin with. If I get the aircraft into a hover myself, so that I am only applying a slight and occasional pressure here and there against the cyclic to maintain the hover, when I engage the Position Hold, all I am doing is telling the hold mode to do those small corrections for me. If I disengage the hold mode (whether that be by turning it off or by pressing the force trim to interrupt it), the SAS sleeves will return to center, but they would only move a very small amount because the aircraft is already trimmed for and in a stable hover.

So the issue isn't that the hold modes or the SAS sleeves are making the pilot's job harder, it's that the pilot is making the pilot's job harder. This is not a criticism on anyone's abilities. Flying helicopters is difficult; even before you add on all the other tasks of navigation, radios, sensors, weapons, making tactical decisions, getting shot at, etc. Future improvements to the flight model will of course help with the predictability of the aircraft, but the underlying logic of how the force trim interacts with the SAS sleeves won't really change. It takes practice, there is no way around it. Heck, when the DCS Black Shark first came out, even as a professional helicopter pilot I struggled to understand its flight computer and autopilot systems. But once I learned the underlying logic behind its automation, it became a joy to fly. We'll get there with the DCS AH-64D.

Thank you for these two wonderful explanations!

I agree with your assessment - fly it the way that works for you. However, to settle my own professional curiosity, how did / do you guys fly the Apache? Do you tend to depress and hold FTR when maneuvering, then release once the attitude is set? Or do you push against the force trim?

I know in the 412 I hold the FTR depressed the entire time when doing precision hover work - this is just my technique as I have fairly steady hands. Others who have a tendency to stir the cyclic I always advise to release the FTR in the hover and make very small corrections against the FTR, only releasing it if a more major change has to be made. Those are our 2 schools of thought, I believe 75% of us probably depress the FTR throughout the hover. Forward flight is typically with ATT mode engaged, depress FTR to set the attitude and then release it until another attitude change is necessary. 

How did / do you guys do it?

Edit: Saw your response in the force trim thread, thanks. Seems like your techniques are pretty much the same as ours. Cheers!

Edited April 29, 2023 by Sandman1330

[cow_art]

Thank you for inputs everyone, much apprechiated.

@Raptor9I am really sorry if I am being dense here, although the information you have given is very welcome I am not sure I completely understand how the three points you mentioned are related to the problem GremlinIV described.

3 hours ago, Raptor9 said:

 

What is still work-in-progress is 1) the CAS logic when the force trim is not pressed, causing some swashplate overshoot when a significant input is applied, 2) the swashplate behavior when the FMC channels are turned off, no mechanical lag applied yet, and 3) the overall stability of the aircraft itself, which is why the aircraft is wobbly when the force trim is pressed. (There are other aspects of the flight model, SCAS, and hold modes that are still work-in-progress as well, but these are the three relevant points in this case)

 

I have made a short video to demonstrate:

(sorry for the crappy recording, I am not exactly a professional youtuber )

As I said, I would really appreciate your feedback on this behaviour! Does the real Apache also behave in this way? Does the nose jerk when FTR is pressed while the pedal position is not perfect?

If not and this is a problem that will still be addressed, how are the three WIP points you have mentioned related to this problem? (Sorry I am not trying to be annoying, I am just trying to understand).

Let me explain:

Quote

 1) the CAS logic when the force trim is not pressed, causing some swashplate overshoot when a significant input is applied,

Does not apply (the problem happens exactly when the FTR is pressed)

 

Quote

 2) the swashplate behavior when the FMC channels are turned off, no mechanical lag applied yet, and

Does  not apply (the FMC channels are on)
 
 

Quote

 3) the overall stability of the aircraft itself, which is why the aircraft is wobbly when the force trim is pressed

I don't think this is an aircraft stability problem. The problem is that the SAS (green line) is changing when the FTR is pressed. The SAS input goes away for a second and then comes back. That's what's causing the right-left motion of the nose.

 

 

 

Edited April 29, 2023 by cow_art

[Sandman1330]

1 hour ago, cow_art said:

I am really sorry if I am being dense here, although the information you have given is very welcome I am not sure I completely understand how the three points you mentioned are related to the problem GremlinIV described

This is what I was trying to address with my response above. I think perhaps the piece of info that you are missing is that, every time you depress the FTR, it tries to align the SAS channels with your pedal position (it does the same for pitch and roll as well, but it's less noticeable).

So if you hit trim with the pedals not aligned with the green line, it will attempt to center the green line with where your pedals currently are, and will cause that jump. The reason it never actually aligns in your case is that it takes a few seconds, and you are just tapping the trim button, rather than holding it.

My suggestion above to hold the FTR helps avoid this. Hold the FTR and apply the necessary pedal input to maintain heading. Then when you release FTR, the SAS doesn't need to deflect away from your current pedal position. Alternately, before you press trim, use your pedals to bring your pedal position in line with the green line in your control indicator. Then your pedals will be in the correct position to counter the yaw and the SAS won't need or try to center (because it's already centered).

1 hour ago, cow_art said:

I don't think this is an aircraft stability problem. The problem is that the SAS (green line) is changing when the FTR is pressed. The SAS input goes away for a second and then comes back. That's what's causing the right-left motion of the nose.

As I hope I was able to clearly explain above, this is exactly what is happening - and it's supposed to do that.

[cow_art]

10 minutes ago, Sandman1330 said:

This is what I was trying to address with my response above. I think perhaps the piece of info that you are missing is that, every time you depress the FTR, it tries to align the SAS channels with your pedal position (it does the same for pitch and roll as well, but it's less noticeable).

So if you hit trim with the pedals not aligned with the green line, it will attempt to center the green line with where your pedals currently are, and will cause that jump. The reason it never actually aligns in your case is that it takes a few seconds, and you are just tapping the trim button, rather than holding it.

My suggestion above to hold the FTR helps avoid this. Hold the FTR and apply the necessary pedal input to maintain heading. Then when you release FTR, the SAS doesn't need to deflect away from your current pedal position. Alternately, before you press trim, use your pedals to bring your pedal position in line with the green line in your control indicator. Then your pedals will be in the correct position to counter the yaw and the SAS won't need or try to center (because it's already centered).

Yes you are 100% correct. That is a solution. It works well but it has some obvious downsides (no stabilisation while FTR is pressed). And there is a lot of semi-official advice going around that only ever mentions clicking the FTR. So what I am trying to find out is basically if press&hold FTR is the only true solution to this problem, or if it is just a workaround we currently need until the SAS logic is more refined (for example waiting 0.1 seconds before the SAS sleeve starts to center would likely fix it)

Edited April 29, 2023 by cow_art

[Sandman1330]

1 minute ago, cow_art said:

Yes you are 100% correct. That is a solution. It works well but it has some obvious downsides (no stabilisation while FTR is pressed). And there is a lot of semi-official advice going around that only ever mentions clicking the FTR. So what I am trying to find out is basically if press&hold FTR is the only true solution to this problem, or if it is just a workaround we currently need until the SAS logic is more refined

Yes, the instability is a bit tough, but with practice you will learn to hover with FTR depressed, despite the instability. That being said, Raptor's explanation above states the instability right now is a bit extreme - it will get better (that's his point #3). The proper, correct way is to hold the FTR. In the interim, until they work on that instability, would be to look at your control indicator and move your pedals to center your pedal position on the green line (SAS position) before trimming. Although not realistic it will alleviate your issue.

They key to remember is that, despite the fact SAS is helping you fly the aircraft, you are still flying the aircraft. So while SAS heading hold is still doing it's job, you should be anticipating the necessary pedal inputs and applying them anyway. This will make SAS's job easier, and ultimately yours! 

[cow_art]

9 minutes ago, Sandman1330 said:

Yes, the instability is a bit tough, but with practice you will learn to hover with FTR depressed, despite the instability. That being said, Raptor's explanation above states the instability right now is a bit extreme - it will get better (that's his point #3). The proper, correct way is to hold the FTR. In the interim, until they work on that instability, would be to look at your control indicator and move your pedals to center your pedal position on the green line (SAS position) before trimming. Although not realistic it will alleviate your issue.

They key to remember is that, despite the fact SAS is helping you fly the aircraft, you are still flying the aircraft. So while SAS heading hold is still doing it's job, you should be anticipating the necessary pedal inputs and applying them anyway. This will make SAS's job easier, and ultimately yours! 

Thanks, all of that is good advice and you are of course right! Just to be sure: I am pretty decent with the FTR depressed. At this point I can pretty much fly the Apache with all the FMC channels turned off (although it's not pretty *lol* ). I'd just like to better understand what quirks are DCSisms which will probably be patched out at some point and what are properties of the actual aircraft that we'll need to get used to

Edited April 29, 2023 by cow_art

[Raptor9]

2 hours ago, cow_art said:

@Raptor9I am really sorry if I am being dense here, although the information you have given is very welcome I am not sure I completely understand how the three points you mentioned are related to the problem GremlinIV described.

My replies were to Floyd1212 (which is why I quoted his posts in mine) and to clarify where a few of work-in-progress areas are. They were not directed toward the problem GremlinIV described, and so are not related at all.

1 hour ago, cow_art said:

Yes you are 100% correct. That is a solution. It works well but it has some obvious downsides (no stabilisation while FTR is pressed). And there is a lot of semi-official advice going around that only ever mentions clicking the FTR. So what I am trying to find out is basically if press&hold FTR is the only true solution to this problem, or if it is just a workaround we currently need until the SAS logic is more refined (for example waiting 0.1 seconds before the SAS sleeve starts to center would likely fix it).

The official advice is to press and hold the FTR as @Sandman1330 stated above. Besides Sandman1330, I'm also saying it, @bradmick is saying it (on the forums and in his Youtube videos), and I think even Casmo has mentioned it a few times on his Youtube channel videos. The intermittent clicking of the force trim leads to problems, both in DCS AH-64D and the real aircraft, as this is the logic of the real aircraft. The SAS sleeves cannot center themselves unless the force trim is pressed and held for 3-5 seconds, it's simply how they work, there is no getting around it.

I think where some of the "semi-official" advice is coming in is from individuals that either haven't flown a real helicopter that are operating off of assumptions, hearsay, or a random internet article on the topic; or those that have flown a helicopter but have flown a type that has a different control system and behavior, and it is lost in translation.

For example, one distinction I want to make is the difference between the term "stabilization" and the different functions of the SCAS (Stability Command Augmentation System). I've heard "stabilization" used to describe the AH-64D's Hold modes, but in the context of the AH-64D, this can lead to confusion. The SCAS functionality of the FMC consists of three "functional areas": CAS, SAS, and Hold modes. The SAS (Stability Augmentation System) provides stability in the pitch, roll, and yaw axes via rate damping when the force trim is not pressed. The Hold modes on the other hand (Heading Hold, Attitude Hold, Velocity Hold, Position Hold) maintain specific reference values of pitch, roll, yaw, velocity, or position when the force trim is not pressed. All three FMC functions (CAS, SAS, Hold modes) use the SAS sleeves within each flight control servo to move the swashplates in accordance with their specific function, but the difference between SAS and the Hold modes is that SAS dampens rotational movement to increase overall attitude stability of the aircraft, but the Hold modes attempt to reach and maintain specific reference values in attitude, velocity and position.

[cow_art]

7 hours ago, Raptor9 said:

My replies were to Floyd1212 (which is why I quoted his posts in mine) and to clarify where a few of work-in-progress areas are. They were not directed toward the problem GremlinIV described, and so are not related at all.

The official advice is to press and hold the FTR as @Sandman1330 stated above. Besides Sandman1330, I'm also saying it, @bradmick is saying it (on the forums and in his Youtube videos), and I think even Casmo has mentioned it a few times on his Youtube channel videos. The intermittent clicking of the force trim leads to problems, both in DCS AH-64D and the real aircraft, as this is the logic of the real aircraft. The SAS sleeves cannot center themselves unless the force trim is pressed and held for 3-5 seconds, it's simply how they work, there is no getting around it.

I think where some of the "semi-official" advice is coming in is from individuals that either haven't flown a real helicopter that are operating off of assumptions, hearsay, or a random internet article on the topic; or those that have flown a helicopter but have flown a type that has a different control system and behavior, and it is lost in translation.

For example, one distinction I want to make is the difference between the term "stabilization" and the different functions of the SCAS (Stability Command Augmentation System). I've heard "stabilization" used to describe the AH-64D's Hold modes, but in the context of the AH-64D, this can lead to confusion. The SCAS functionality of the FMC consists of three "functional areas": CAS, SAS, and Hold modes. The SAS (Stability Augmentation System) provides stability in the pitch, roll, and yaw axes via rate damping when the force trim is not pressed. The Hold modes on the other hand (Heading Hold, Attitude Hold, Velocity Hold, Position Hold) maintain specific reference values of pitch, roll, yaw, velocity, or position when the force trim is not pressed. All three FMC functions (CAS, SAS, Hold modes) use the SAS sleeves within each flight control servo to move the swashplates in accordance with their specific function, but the difference between SAS and the Hold modes is that SAS dampens rotational movement to increase overall attitude stability of the aircraft, but the Hold modes attempt to reach and maintain specific reference values in attitude, velocity and position.

I see! Great, thanks for taking the time to explain it in such detail!

[firefox121]

hace 20 horas, Raptor9 dijo:

My replies were to Floyd1212 (which is why I quoted his posts in mine) and to clarify where a few of work-in-progress areas are. They were not directed toward the problem GremlinIV described, and so are not related at all.

The official advice is to press and hold the FTR as @Sandman1330 stated above. Besides Sandman1330, I'm also saying it, @bradmick is saying it (on the forums and in his Youtube videos), and I think even Casmo has mentioned it a few times on his Youtube channel videos. The intermittent clicking of the force trim leads to problems, both in DCS AH-64D and the real aircraft, as this is the logic of the real aircraft. The SAS sleeves cannot center themselves unless the force trim is pressed and held for 3-5 seconds, it's simply how they work, there is no getting around it.

I think where some of the "semi-official" advice is coming in is from individuals that either haven't flown a real helicopter that are operating off of assumptions, hearsay, or a random internet article on the topic; or those that have flown a helicopter but have flown a type that has a different control system and behavior, and it is lost in translation.

For example, one distinction I want to make is the difference between the term "stabilization" and the different functions of the SCAS (Stability Command Augmentation System). I've heard "stabilization" used to describe the AH-64D's Hold modes, but in the context of the AH-64D, this can lead to confusion. The SCAS functionality of the FMC consists of three "functional areas": CAS, SAS, and Hold modes. The SAS (Stability Augmentation System) provides stability in the pitch, roll, and yaw axes via rate damping when the force trim is not pressed. The Hold modes on the other hand (Heading Hold, Attitude Hold, Velocity Hold, Position Hold) maintain specific reference values of pitch, roll, yaw, velocity, or position when the force trim is not pressed. All three FMC functions (CAS, SAS, Hold modes) use the SAS sleeves within each flight control servo to move the swashplates in accordance with their specific function, but the difference between SAS and the Hold modes is that SAS dampens rotational movement to increase overall attitude stability of the aircraft, but the Hold modes attempt to reach and maintain specific reference values in attitude, velocity and position.

One question about those who fly the Apache with a non spring joy, or with a FFB like microsoft sidewinder ff2.

In that situation, must I press and hold the force trim button, or because the nature of my joy (is configured to maintain his position when I am not touching it)? or simply release the joy in his position without pressing the force trim?

Even using the atthold mode and altitude mode.....pressing the respective buttons.

Thanks