Trimming the hind trims the heli with slightly more pitch up than where the stick is held

[Darlakan]

When pressing the trim button in the hind the stick position gets locked in a slightly more pitch up (pulled towards) position than it was held when the button was pressed. this results in the helicopter nosing up when ever you trim.

 

you can see this when not moving the stick and pressing the trim button the stick will trim slightly towards you when pressed.

 

Edit: made a track file of the issue, did a hotstart on ramp and air start. Trim issue seems to only be there when AP Pitch and Roll is enabled.

Hind Trim Issue.trk

Edited June 21, 2021 by Darlakan
Added track file for more info

[Marklar]

Yes, I noticed that too. It's easier to trim just using a HAT switch.

[VampireNZ]

Noticed this also - much harder to trim and return stick to ctr than in the HiP/Huey. 

[Nealius]

Happens on all axes. With my stick centered, I will often set trim to just correct some yaw, and I will see the vitual stick jump left or right even though my physical stick is centered.

[Highwayman-Ed]

+1, it seems to over compensate for where the trim is set.

[NineLine]

Hey guys, we really needs tracks for this to see what's going on, many of you know the drill already. Thanks.

[RealDCSpilot]

Have you guys set curves on X and Y axis? Try again with linear setting and report back.

[Nealius]

0 curves for me. 20cm stick extension.

[Blackeye]

7 hours ago, NineLine said:

Hey guys, we really needs tracks for this to see what's going on, many of you know the drill already. Thanks.

 

Here's a track: Air start, then trimming for forward flight, then bring the nose onto the horizon, trim and the nose moves further up.

After that a similar demonstration just with bank.

 

It seems to work somewhat similar to the Ka-50 in that regard so it may not be a bug, but I was under the impression that it should behave more similar to the Mi-8 where the flight attitude does not change after you trim and put the stick back to zero.

 

Apparently the AP channel corrections are set to 0 when you press down on the trim button, but on release they return to their previous state, commanding that extra pitch or roll or at least it seems to depend on how much offset the AP channel indicators were when you press trim.

 

Track was made with the return to center trimming option but it behaves the same way with the default option.

demo.trk

Edited June 21, 2021 by Blackeye

[SchwappingMags]

Its the autopilot channels return to center when you press the trim button, I think this is a bug? 

Since the trim button in the mi-8 is very very smooth and doesnt introduce any jerk at all from the autopilot channels.

[Blackeye]

3 minutes ago, SchwappingMags said:

Its the autopilot channels return to center when you press the trim button, I think this is a bug? 

Since the trim button in the mi-8 is very very smooth and doesnt introduce any jerk at all from the autopilot channels.

 

That would be my guess ATM as well - however I have no idea how this thing works IRL, so it may be realistic and perhaps the Mi-8 is wrong or just different.

[VitMax]

Actually, it's the other way around -- Mi-8 and Mi-24 autopilots should work differently. Unlike in Mi-8, In Mi-24 pressing the trim button should center autopilot at this new location of cyclic. But in the sim right now autopilot works incorrectly.

Currently, when you press the button autopilot channels reset to the neutral positions as they should, but after you release trim button they return to the previous state, which causes unintended movement. You can see that at autopilot indicators -- when button is pressed bars should go to their neutral positions and stay there, but right now they move back the moment button is released, causing pitch and bank to fluctuate.

[DrGonzo94]

I get this too, trim is always slightly off, and different to all other helos in "Central Position Trimmer Mode". Feature or bug? 

[Blackeye]

8 hours ago, DrGonzo94 said:

I get this too, trim is always slightly off, and different to all other helos in "Central Position Trimmer Mode". Feature or bug? 

 

Bug according to this

 

[solus]

I guess, I have this overtrimming issue too.

 

Choosing "return to the centre" (not the default) under joystick controls in Mi24 specific options section helped a lot. 

[VampireNZ]

Really hope this is getting some priority by ED, instead of hiding behind the 'need a track/missing info' tag - as this is major PITA #1 with this module at the moment.

 

Yes you can fly around it, but jeeze it is like a box of chocolates every time you are in stable flight and hit the trimmer button...never know what you are going to get 

[examors]

15 hours ago, VampireNZ said:

Really hope this is getting some priority by ED, instead of hiding behind the 'need a track/missing info' tag - as this is major PITA #1 with this module at the moment.

 

Yes you can fly around it, but jeeze it is like a box of chocolates every time you are in stable flight and hit the trimmer button...never know what you are going to get 

Agreed. Disappointed to see there is no fix in today's patch notes. I have just given up flying the Hind until it's fixed; it's too frustrating with this bug.

[Schlomo1933]

Any news on this ? 

[sylkhan]

Unfortunately No, Fm & trimming in the Hind bugged or bad design, but some seems to be happy with that.
They have always good reason to explain why things are like they are :)., even if there is no logic.
Trimming means stabilization.
For the Hind trimming means jumping, diving, rolling left or right, just a joke.
It's impossible that the Real Hind has this trim mechanic.
Trimming the Mi8 is perfect and it seems that it's not the same team who devellop the FMs/trim for the hind & the Mi8

I don't fly the Hind anymore, waiting for correction (eventually).

[admiki]

50 minutes ago, sylkhan said:

Unfortunately No, Fm & trimming in the Hind bugged or bad design, but some seems to be happy with that.
They have always good reason to explain why things are like they are :)., even if there is no logic.
Trimming means stabilization.
For the Hind trimming means jumping, diving, rolling left or right, just a joke.
It's impossible that the Real Hind has this trim mechanic.
Trimming the Mi8 is perfect and it seems that it's not the same team who devellop the FMs/trim for the hind & the Mi8

I don't fly the Hind anymore, waiting for correction (eventually).

If there are good reasons, even if it doesn't seem logical to you still makes them good reasons, maybe you should accept those. 

Answer is no. Stabilization is provided via SCAS/AP systems. Trimming means taking out control forces which in return enables finer/easier control.

Again, no.

Just because you think that Mi-8 and Mi-24 are the same doesn't make it true. 

IRL, AP systems work as they do in DCS, with only difference that you don't feel out-of-trim stick forces unless you have FFB.

Mi-8 FTR does not affect AP, in Mi-24 it does, so you either hold FTR while changing position or click it a lot, even in Mi-8 to cancel out-of-trim forces (and before you say how this is unrealistic, take a look here and listen for FTR clicks)

In Mi-24, once you are done with large position changes, you use beep trim (which Mi-8 does not have to fine tune it)

Regarding bug from OP, only overtrimming issue is when I am in instant trim mode, which is for FFB sticks only. In central trimmer mode, trim works just as it should.

[sylkhan]

1 hour ago, admiki said:

In central trimmer mode, trim works just as it should.

No overtrimming is always here, and if you fly the hind from the start, you should see that there some improvement in this departement.
And the bugged FMs (occiliations at low speed,and a lot of others things), do you have an explanation ?

Think what you want, but trimming the real hind or others chopers will never makes them jumping, diving, rolling left or right.

[admiki]

3 minutes ago, sylkhan said:

No overtrimming is always here, and if you fly the hind from the start, you should see that there some improvement in this departement.
And the bugged FMs (occiliations at low speed,and a lot of others things), do you have an explanation ?

Think what you want, but trimming the real hind or others chopers will never makes them jumping, diving, rolling left or right.

Watch both your stick and controls indicator, they don't move when you press FTR. It's not overtrimming, it's AP reseting. If you hold FTR before you move stick, there is no jumping. IRL Hind pilot told me that is how it works.

Oscilations are a bug, just like many others and I never denied those (if you look, you can find a thread I started taking a shot at ED for not fixing those).

[River]

The Hind trim doesn't work like it should period. All other helos in DCS work fine.  The aircraft is clearly overshooting the trim command. 

[AeriaGloria]

9 hours ago, River said:

The Hind trim doesn't work like it should period. All other helos in DCS work fine.  The aircraft is clearly overshooting the trim command. 

Does it happen when you trim while on the ground? 
 

The trim causes the AP/SAS to go to zero. So when you press it any input from Autopilot goes away, this can cause a lot of jumping in pitch or roll if you trim after maneuvering a lot from the last attitude you trimmed in. 
 

But if it’s moving the physical stick when you just press trim on the ground or in active pause, then yeah it’s an issue 

[sylkhan]

4 hours ago, AeriaGloria said:

... this can cause a lot of jumping in pitch or roll if you trim after maneuvering a lot from the last attitude you trimmed in.

No need to manoeuvring a lot for this to happen.

It happens each time you trim, if the AP is not in neutral position at the moment you trim.

Fly level, pitch down 5° and trim (and see what happen)