Pedals Trimmer mode - no setting for pedals without spring or FFB

[zerO_crash]

25 minutes ago, jojojung said:

Thanks for clarafication. That was not known to me. You say the stabilization mode is on even when the yaw AP is completly off, right? Before my stand of information from @AeriaGloria Autopilot Guide sounds a bit different. There it sounds more then the stabilization mode is only active, when the yaw AP is on. But its not 100% clear in this guide. It left space for your explaintation, that stabilization is on all the time no matter of the yaw AP engaged or disengaged.
In your logic the microswitches are only there to turn the yaw AP with its only heading hold function on and off because stabilization mode is on all the time, right?


"Section B: Section B, Part I: The system in reality and Operation.

A. When feet are on pedals in Mi-8 (micro switches pressed) the
heading hold does nothing. In Mi-24P, the Yaw channel enters
Stabilization mode.

B. when feet are off pedals in Mi-8 (micro switches released), the
yaw AP goes into heading hold mode and maintains heading using

its 20% authority (18% in Mi-24P), and when it reaches this limit it
will use the hydraulic damper in the pedals SDV-5000-OA (which
usually just slows down pedal movement) to trim the pedals for you
to maintain heading.
The only difference between Mi-8 Yaw channel with Mi-24P in
reality is that, when the yaw AP is not in heading hold and feet are
on pedals (micro switches pressed), Yaw AP goes into a
Stabilization Mode."

 

 

Again, I reiterate, I haven't commented on "stabilization", other than stating that it's not to be confused with the automation that you find in Ka-50. In the DCS manuals, it is stated that the AP has stabilization - while not wrong, it is often confused with the level of automation of Ka-50 AP suite. I did, however state, that "damping" is can be toggled (on/off - red switch shown earlier) regardless of AP YAW operation.

 

I see that you get those confused, so let me explain:

 

Damping - This is essentially a filter that overlaid controls which is supposed to grant a more fluent flight, and that by minimizing excursions of the controls. It's not supposed to limit control travel, but rather, see whether the control input was momentary, or sustained. Example; if you fly, and all of a sudden move the cyclic to either extreme (left/right/fwd/aft), and then return the cyclic back to neutral quickly, the maximum control will be filtered out resulting in a much lower control movement shown to the flight control system. In practice, even though you maxed out the cyclic in either direction, and momentarily moved it back to neutral, the hydraulic actuators driving the swashplate only managed to move a certain percentage of that, but much less than what you requested (this is also in part due to control reactionary delay - the time it takes for the system to give you what you requested).

 

Now, there are many ways to add such a filter, it can either be in the autopilot (Ka-50 for example), or it can be simply a heavier control stiffness. In Mi-24P (and Mi-8), the dampening is done in a mechanical way, as you outlined by SDV-5000-OA. In order to remove unwated small and imprecise control inputs, you make the controls heavier. That way, only intentional control inputs will be registered. This sluggishness (SDC-5000-OA operation), is in essence what that red switch toggles (on/off). It's more advanced than you think, though, as it needs to be able to change the forces with regards to trimmed position of the pedals, and also, if AP YAW is operating (AP YAW on, and feet off pedals), then it cannot fight the corrections made by AP in order to hold a given heading. Still, some of that functionality does not function if AP YAW is off - it only dampens.

 

Stabilization - This is something very different than dampening. Stabilizaiton, is essentially the ability of the AP (or aircraft in general) to hold a given metric, that the pilot requested upon releasing the trim button. Normally, you'd think that trimming is purely mechanically altering the zero-point of the control column (cyclic/collective), however, that is not the whole truth. In the first of aircraft, it did just that. With the inception of autopilots and flight computers, however, the functionality got much more expanded and advanced. While you still trim the control column by releasing the trimmer, you also tell the aircraft what metrics you wish the AP (depending on the composition of modes) to hold. It's called stabilization, because it isn't a purely human-mechanical interation, instead, you input system logic in there (human-system(AP)-mechanical). The effect is then that the aircraft will apply the mechanical trim, and also give reference values to flight computer (AP) to hold. If wind impacts your aircraft, or with speed, it will want to change relaxed position, the AP will operate within its boundary to try and nevertheless maintain the aspect requested by the pilot. 

 

The stabilization in Mi-24P and Mi-8 is mostly steming from a analogue computer, hence why I'm saying that you should keep it clear apart from e.g. how Ka-50 is operating. There really is no overlap there. I'll also add here a interesting nuance which most are not aware of:

 

In the Mi-24P, you have two types of trim. You have the trimmer button, and the trimmer switch. The trimmer button, operates as described above - it gives the command to zero out the forces on the cyclic as well as setting reference values for active APs to hold. The trimmer hat, however, is completely disconnected from the system. It is purely mechanical, and bears no impact on the AP whatsoever, it's not connected in any way. If you think about it - if you use the trimmer button at the start of the flight once, then resume the flight by using trimmer hat only, and finally decide on letting the system operate again (take feet off pedals), you can actually destabilize the whole airframe pretty bad (it won't be catastrophical, but certainly ineffective flight-wise). Consider, that mechanically, you might have moved further away from the trimmed position you requested with the trimmer button. Still, the AP will remember YAW bearing you requested. In other words; mechanically, the helicopter will be trimmed for a different flight with the cyclic, than what the AP tries to maintain with AP YAW. That's why it's important to always use the trimmer button at least once, before handing off full control to the AP (feet off pedals - e.g. you want to demonstrate auto hover).

 

That should clear it up.

[AeriaGloria]

On 4/23/2025 at 2:58 PM, zerO_crash said:

Re-read what I wrote:

 

I state that microswitches put the "heading hold AP" in standby. I make, however, no mention of the dampening in that statement, and for good reason - in the Mi-24, the heading hold AP is entirely disconnected from the dampening fucntion (there is no stabilization, this is not Ka-50).

 

I won't link Russian manuals, as you'd likely not understand them anyways, but here is a picture showing which switch in the cockpit operates the yaw damper (image is from Chuck's manual for simplicity):

 

 

When talking about the Mi-8/Mi-24/Ka-50/+++, you have to be very careful not to mix the systems up. They have their differences and nuances, with Ka-50 being entirely different than Mi-8/-24, which have some overlap. 
 

EDIT: To correct you and make it clear - Mi-24P has yaw dampener actuated regardless of the operation of the heading hold AP. Provided that the damper is engaged (default position), it operates all the time, whether the heading hold AP is on/standby/off.

 

On 4/24/2025 at 5:52 AM, jojojung said:

Thanks for clarafication. That was not known to me. You say the stabilization mode is on even when the yaw AP is completly off, right? Before my stand of information from @AeriaGloria Autopilot Guide sounds a bit different. There it sounds more then the stabilization mode is only active, when the yaw AP is on. But its not 100% clear in this guide. It left space for your explaintation, that stabilization is on all the time no matter of the yaw AP engaged or disengaged.
In your logic the microswitches are only there to turn the yaw AP with its only heading hold function on and off because stabilization mode is on all the time, right?


"Section B: Section B, Part I: The system in reality and Operation.

A. When feet are on pedals in Mi-8 (micro switches pressed) the
heading hold does nothing. In Mi-24P, the Yaw channel enters
Stabilization mode.

B. when feet are off pedals in Mi-8 (micro switches released), the
yaw AP goes into heading hold mode and maintains heading using

its 20% authority (18% in Mi-24P), and when it reaches this limit it
will use the hydraulic damper in the pedals SDV-5000-OA (which
usually just slows down pedal movement) to trim the pedals for you
to maintain heading.
The only difference between Mi-8 Yaw channel with Mi-24P in
reality is that, when the yaw AP is not in heading hold and feet are
on pedals (micro switches pressed), Yaw AP goes into a
Stabilization Mode."

 

Jojojung is correct, I believe you are mixing up two different types of “dampeners” Zero_Crash 

Yes. There is the “SDV-500-OA” which is a literal hydraulic dampener, it is not advanced or smart in any way but only slowing down any movement of the pedals from center to full to 3 seconds and being able to be filled by the autopilot to move the pedals on their own if your settings are set that way. And yes it’s turned off with the red guard. 
 

But if you turn Yaw AP on and press microswitch there is still a dampening/stabilization function in the autopilot that is completely separate. This function works off not fighting yaw rate, but changes in yaw rate. So if I turn left, it will “dampen/fight/stabilize” the initial turn to the left, but as the turn to the left stabilizes it will go back to neutral. 
 

You can see this work in the simulator by using R control + enter and looking at the yaw window with yaw autopilot on and microswitch pressed. It will move the channel 20% for every deg/s/s of acceleration, just like how the channel moves 20% for every deg/s of acceleration in normal heading hold. 
 

Becuase of confusion of these two “dampeners,” I have tried to shy away from calling it such and say “stabilization” mode, which some real life sources say as well. 
 

This “stabilization” law that is active with Yaw AP while microswitch is pressed was added after Dutch roll issues reared their ugly head, , so it was meant to make that and all high speed flight much smoother 

In addition, the Trim hat is connected to the Mi-24 AP! When you press and release trim 2 things happen, it not only resets the deflection of the attitude holds, but there is a second autopilot law that it inherits from Mi-8: the autopilot will deflect the attitude holds in the same direction the stick moves to not fight the pilot and reduce the need for re trimming! 
 

You can see this on the ground, move the cyclic with R control + enter and you will see the autopilot channels follow your cyclic! This is why having autopilot on can actually INCREASE your control authority to an extent! 
 

However, to do this, it needs to know where “center” is. Oh Mi-8, it just took wherever your stick was when you turned it on, same as for attitude holds. So for Mi-24, your trim is resetting the attitude hold and where “center” is, so if you’re cyclic was previously commanding any autopilot deflection it goes away after pressing trim. 
 

When you press hat trim, it is also telling the autopilot to move this “center” but NOT moving the attitude holds. So it’s a sort of half measure and why of course in the end nothing can replace re trimming. You can see all this work on the ground. Move your cyclic right, you will see roll autopilot deflect right. Hold it there. Hold right hat trim, you will see the roll autopilot steadily go back to center as your “center” is moving right. 

Edited May 1 by AeriaGloria

[AeriaGloria]

On 4/22/2025 at 9:41 AM, Chops said:

I am re-learning the Mi-24P and having a lot of difficulty.  I have read through this thread a few times, but am still having trouble with the special settings and understanding what is going on with the helicopter.  Some of the settings seem redundant and contradictory. 

Why hasn't a manual been released that describes all of the special settings in detail?  This module has been out for over 4 years and no manual has been released!  This should be considered totally unacceptable by Eagle Dynamics.

It would be very helpful if there was an option to return all of the settings to default.  I uninstalled and then re-installed the module but it kept my special settings.

I want to have the heading hold enabled for cruise flight between waypoints, but also want to have full control of the pedals when maneuvering.

Attached is a screenshot of my settings; are these correct for what I want?

Hello Chops, I made a guide for the autopilot, in there there is a chapter where I go through every single special options settings, it might be able to help, if not I can answer any questions https://drive.google.com/file/d/157HdRauUQO8rUJypKMnWrOktTjWqyMBE/view?usp=drivesdk

Here is what I would recommend based off your screenshot

1. Turn “Pedal auto move” off, this gives heading hold more authority by trimming your pedals, but often causes control issues especially when heading hold is accidentally activated and you lose overall authority from pedals being trimmed. The normal 18% authority is usually plenty for heading hold to get you from point A to point B 

2. Turn “Microswitch logic” either to “disable by return pedals to center” or “automatic off.” But really, what I honestly recommend after all my years is to go “automatic off” and bind “microswitch toggle,” and use this as your “heading hold” button. Just when you start up, turn on your auto pilot, also press your “microswitch toggle,” this will put the put the yaw autopilot into a mode that is helping you fly smooth but not holding heading. Then when you want to activate heading hold just press microswitch toggle and once again to turn it off. Know how each autopilot channel has a dial? If you are having trouble conforming if your heading hold is active or not, move the dial and if it moves the needle in the window above it then heading hold is active! 
 

Or if you have R control + enter window open, and if the left most AP window is fighting your turn, then you know heading hold is on. You can do the same thing without R control + enter display by looking at the same AP windows by your left knee. 
 

To be honest though, I almost always fly heading hold with microswitch pressed (heading hold off), becuase if you want to fly from point A to B hands off you know what’s even better? Route mode! On top of autopilot panel you have buttons route mode, hover button, etc. Route mode will only work when Doppler is active (it has pitch limits of +/-7 degrees and roll limits of +/-30 degrees), but becuase it uses Doppler that means it corrects for wind! 
 

It’s a little more work then heading hold, you have to set your heading with a dial to the left of the autopilot panel. But it will compensate for wind PERFECTLY! Just make sure when you’re done using it to press the “OFF” button next to it, becuase even if it turns off automatically from exceeding Doppler limits it’s last inputs will be “saved” in the autopilot and mess you up. 
 

If you instead choose the “disable microswitch by moving pedals to center,” I would recommend to only turn on Yaw AP when you want heading hold and turn it off when you’re done! Becuase if you leave it on in this mode it can accidentally turn on or off at the wrong time and interfere. 
 

Let me know if there’s anything else you want to know! 

Edited April 25 by AeriaGloria

[LuseKofte]

Thanks @AeriaGloria for your continuous seemingly endless knowledge you share with us. 
I flown this module pretty much every time I start DCS since it came out. 
I never knew it even had a hoover button. I messed a lot with the autopilot at first, but soon I just trimmed it. I am not with my computer right now. But I just trim it for what ever speed I want. 
But I will look into this 

Always something new to learn. 

[AeriaGloria]

12 hours ago, LuseKofte said:

Thanks @AeriaGloria for your continuous seemingly endless knowledge you share with us. 
I flown this module pretty much every time I start DCS since it came out. 
I never knew it even had a hoover button. I messed a lot with the autopilot at first, but soon I just trimmed it. I am not with my computer right now. But I just trim it for what ever speed I want. 
But I will look into this 

Always something new to learn. 

The hover button is very finicky! 
 

1. It will try to stabilize you over a particular spot, so you need to only turn it on once you are already in a hover! 
 

2. Just like route mode, since it uses Doppler, it is turned off as soon as you exceed Doppler limits (7 degrees pitch or 30 degrees roll). Now, normally you hover at 3.5 degrees nose up. So what happens if you have any forward speed and press hover button? The hover mode commands nose up to get you to go back to the spot you turned it on over, you exceed the 7 degrees pitch Doppler limit, and it turns off. Add things like tail winds, needing to back up, and it might turn off a lot, so you might need to keep turning it back on! 
 

And just like route mode, if it turns off on its own, its last command is “saved” in the autopilot and will interfere with you. So when you are actually done with it you NEED to press the “OFF” button or it will keep messing you up for the rest of your flight. 
 

Sometimes it can be a nice crutch to turn on the hover mode before takeoff and have it help you takeoff straight, then turn it off as you start building speed!