Does trim work as it is supposed to?

Hey guys, just a quick question.

Is there something wrong with the trim function? I have just started learning to fly the Ka-50 and trim seems to behave strange.

I would expect when I move my stick to a position so the nose is down, let’s say, by -10 degrees, press the trim button and move my stick back to neutral, that it kind of stays at these -10 degrees. But what it does it seems to over correct like double and then the nose goes down somewhere in the region of -20.

This happens when I do a short or long press. With the long press you just have the chance to correct this, so when you release the button your pitch is where you wanted it.

This only happens when the Autopilot for pitch and roll is engaged. Without these Autopilots everything seems to work fine and I actually got a more stable flight.

I’ve been flying the Mi-8 for almost a year now and there it works perfectly. I would have expected it to behave the exact same way here…

Am I missing something? I haven’t finished the manual yet, but searched for trim and I found nothing described like this.

I tested in in the Beslan take off instant mission in 1.5.8 and 2.5OB

Any help would be appreciated.

You are fighting the flight stabilization. If you go -10 you actually are going -10 plus the amount needed to fight the autopilot. Trim in director override mode then flip it off. Many new pilots kill themselves trimming at low level as it jumps down as they actually trimmed an extra 1-20 degrees..

It's bugged using a FFB stick as it commands erroneous extra pitch , even in FD mode. I tested by locking my joystick rigid and mapping the trim button to seperate control so there was no movement of the joystick at all. It's possible to do front flips just by repeatedly tapping the trim button!

I fly Ka-50 with the 3-amigos push buttons (Bank, Pitch and Heading) and usually use the Flight Director push button using a CH Products Fighterstick. I use the "Central Position Trimmer Mode" selection in OPTIONS \ SPECIAL tab for the Ka-50 .

I usually fly freehand in Flight Director not using the Autopilot Route Mode switch found on the collective stick.

And trim as is necessary.

See Chuck's Guide Chapter 3, page 27 I think :

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https://drive.google.com/file/d/0B-uSpZROuEd3OTdRSGhSSGtCTzQ/view

If you have CH Products gear, there is a really great profile available for download at CH Hangar by Capt Crunch which is what I use.

If you want to try my DCS Axis Tune controllers profile just ask me. I'm usually flying currently on "Operation Longbow" on the 104th's server, usually night missions and which Ka-50 excels at.

I learned Ka-50 first. Mi-8 does trim the same as the Shark, but I also use the Mi-8's autopilot as instructed in its Flight Manual and mapped a button for "Adjust Autopilot" and I ask the Flight Engineer for help as needed; how-to directions are in the DCS Flight Manual for the Mi-8. My experience? Flying the Ka-50 is easier.

On the Ka-50 you have to push the trim button BEFORE moving the stick, then move the stick to get the pitch you want and release trim button. Repeating those steps several times adds new trim input to previous stored amount.

In your case you get pitch -10 by moving the stick, then by pushing trim button you ADD -10 (trim value from neutral stick position to actual position). That way you end with twice the value you intended to get.

its sooo much easier just to use the other trim, forgot what its called as not at home, but if using something like a warthog stick, you just trim, then no movement will happen till you let the stick centre, once you have got used to this its a far more natural and easy way to fly, plus you don't get the auto pilot re correcting your initial movement

its sooo much easier just to use the other trim, forgot what its called as not at home, but if using something like a warthog stick, you just trim, then no movement will happen till you let the stick centre, once you have got used to this its a far more natural and easy way to fly, plus you don't get the auto pilot re correcting your initial movement

Just to add my two cents...

I think learning the trim in the Ka50 comes down to your own personal preference. Try all the options available, of which there are a couple ways. The Ka50 is not like any other heli or jet when it comes to trim, it is it's own beast. I spent hours and hours just flying around and trimming using various methods. How to trim it "just right" for the perfect hover, or how to trim it "just right" for Route Mode. Normally I rarely trim, because the Shark is so stable to begin with all you really need is Bank/Pitch AP. If you're flying with Heading AP on, you're constantly fighting it while turning. You can turn Heading AP off and back on again to "trim" to your new heading.

Anyway, I think it all just comes down to your personal preference and hours and hours of trial and error. Much like the assignments on your HOTAS, I doubt anyone would prefer my setup. But it's just second nature now which button is for what. I have the 2 Cougar MFDs and the Warthog, an it took me a good 3-4 months to get it just right.

Also people have hated when I've said this before. But READ the manual, believe it or not there is A LOT of good information to help. I don't say it to be mean, I just say it because the Shark in MY opinion is the most deadly of all the aircraft in DCS, IF you know the systems and how to employ them properly.

Reaper6

I bound cyclic inputs to my trim hat. This way I can achieve the same effect for small changes the same way as all the other helos work. It works out for me to be a much smoother and more controlled flight experience.

I still use the magnetic brake trim, but lately I fly in director mode almost all the time unless I have a need for route following mode AP. As stated MB trim in director mode seems to be a lot more manageable.

Takeoffs for instance:

1 - Director mode on.

2 - Two taps forward on the trim hat

3 - Pull in slow collective

4 - Rise straight up like a bowss.

Many other applications of this, such as smoothly transitioning from cruise speed to a hover, and then trimming that hover out precisely. I don't even need to use the alt and hover hold anymore.

This has been a transformative discovery for me in the KA-50.

If you search the forums you will find numerous threads about this subject.

All of them arrive at the conclusion it works as intended by Kamov.

You will find a host of posts by people saying saying that it doesn't work for them and that you should fly with the AP channels off, or the FD always on etc. etc., but in the end, Kamov, designed the aircraft to be flown with the AP channel on, and for the most part, the FD off.

My personal advice would be hit and hold trim before moving the stick, otherwise you are fighting the AP as you go, and if you have a FFB stick, don't have curves in your set up.

It's bugged using a FFB stick as it commands erroneous extra pitch , even in FD mode. I tested by locking my joystick rigid and mapping the trim button to seperate control so there was no movement of the joystick at all. It's possible to do front flips just by repeatedly tapping the trim button!

It is, but only if you weren't actually trimmed for constant speed / altitude in the first place.

I use an MSFFB II (no axis curves), and I just went away and tested this.

If you get trimmed so that with the trim button held, you're flying level at a steady speed, then release and repeatedly re-trim you won't deviate from that level and speed.

If you don't trim correctly, then rely on the AP channels to maintain your course & attitude, or your speed is changing as you fly level, then yes - if you repeatedly tap trim the aircraft will pitch up (or down) - as you'd expect.

Not sure i follow

It is, but only if you weren't actually trimmed for constant speed / altitude in the first place.

 

Trimming is by it's nature transitionary, if we were always "trimmed for constant speed/altitude in the first place' there would be no need for trim. This seems like circular logic.

 

If you get trimmed so that with the trim button held, you're flying level at a steady speed, then release and repeatedly re-trim you won't deviate from that level and speed.

But isn't push and hold trimming the incorrect method for FFB?

If you don't trim correctly, then rely on the AP channels to maintain your course & attitude, or your speed is changing as you fly level, then yes - if you repeatedly tap trim the aircraft will pitch up (or down) - as you'd expect.

With FD on unless i'm mistaken, there should be no AP at all, only damping of the channel. So where is this extra uncomanded pitch coming from?

To my mind it appears ED have left in code in the FFB trim mode that should only appear in the non FFB trimming modes, i.e they are artificialy simulating a 'jump' when relieving forces on a non FFB stick, which you don't need to on a FFB stick because it actually, physically moves.

Not sure i follow

Then I'll try to explain

Trimming is by it's nature transitionary, if we were always "trimmed for constant speed/altitude in the first place' there would be no need for trim. This seems like circular logic.

Think of it like the Su-27.

You trim for an airspeed / attitude.

If you change the speed, the aircraft is out of trim & will change attitude.

With The Ka-50, you're at a speed and attitude then you trim.

Now you change speed. without the AP you'd have to adjust the cyclic to maintain your current attitude.

But you have the AP on, so now you have the AP channels adjusting the controls for you as you change speed to hold you attitude and heading.

When you next push the trim button, the AP stops making that adjustment, and you're just in an aircraft where the cyclic isn't in the right place to maintain that attitude at that speed.

Trim often, (& with the press, move, release method) and the deviation between where the cyclic will currently take the aircraft, and where it's actually going will be minimal.

If you get the aircraft stable in speed and attitude, then trim, next time you trim there won't be any mismatch.

But isn't push and hold trimming the incorrect method for FFB?

My understanding is it's one of the accepted methods for the real aircraft, and it works fine in sim. Press trim, move the cyclic, release the trim. If you hold the trim (for a fraction of a second) till the aircraft has stabilised at the pitch that corresponds to the cyclic position, there won't be any mismatch caused by the AP.

Or you can trim very often, so that the amount of 'corrective' input from the AP is never large enough to cause a large jump.

If you move the cyclic a significant amount then trim, the AP will be fighting what you're doing & so negating some of your input. When you do trim, that negation will be removed and you'll get the full effect of the movement you've added to the cyclic, resulting in a jump in the direction you moved the cyclic.

With FD on unless i'm mistaken, there should be no AP at all, only damping of the channel. So where is this extra uncomanded pitch coming from?

I didn't mention the FD, and if I enable FD, hold the stick still and repeatedly trim I don't get any deviation in pitch or jaw.

To my mind it appears ED have left in code in the FFB trim mode that should only appear in the non FFB trimming modes, i.e they are artificialy simulating a 'jump' when relieving forces on a non FFB stick, which you don't need to on a FFB stick because it actually, physically moves.

I disagree. See the first part of my reply.

Are you sure you don't have any curves or reduced saturations set up on your controller axis ?

Right, cheers for that Weta, but what version are you testing in because mine definitely isn't functioning as you describe, and no, no curves or saturations or deadzones.

I'm not playing much in 2.5 because of the terrible performance issues, is it possible this is patched in 2.5 but not 1.5.8?

I'm not playing much in 2.5 because of the terrible performance issues, is it possible this is patched in 2.5 but not 1.5.8?

No, works the same. Just follow Reaper6 suggestions and fly much with all methods to find what suit you. I have flown with the default trimming method selected in the settings and press-n-hold when flying for many years up till recently. Switched to "without FFB and spring" a while ago (and increased cyclic friction) and without noticing it myself my in flight method changed to repeatedly kicking the button frequently whenever changing attitude. Was very surprised when I realized it. But it really feel natural and smooth for me with the selected setting. At some situations (evading incoming) I still use the press-n-hold though.

Yeah Weta and Reaper definitely have the right info here.

No Problem.

It was 1.5.8I went away and tested in.

Just to avoid any confusion, when I press and hold, I just use the standard FFB setting in the axis setup & trim by - engage trim, move cyclic, stabilise airframe, release trim.

Hopefully not just repeating myself without adding clarity, but this is how I conceptualise it, and it seems to work:

Assume the AP tries to keep you going where you were going where the trim was released.

If that doesn't match where the cyclic is positioned for at the time trim is released (because the aircraft was still changing orientation at the time the trim was released) the AP will enter input to try to get back to that 'trimmed' alignment, and the trim will cause a jump next time it's pressed as those AP inputs are released.

To avoid that, steady the nose before releasing the trim.

... steady the nose before releasing the trim.

Can't be stressed enough!

(for press-n-hold method that is)

 

Assume the AP tries to keep you going where you were going where the trim was released.

If that doesn't match where the cyclic is positioned for at the time trim is released (because the aircraft was still changing orientation at the time the trim was released) the AP will enter input to try to get back to that 'trimmed' alignment, and the trim will cause a jump next time it's pressed as those AP inputs are released.

 

To avoid that, steady the nose before releasing the trim.

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The way it works.

Thanks for all the answers and tips

I didn’t want to start a big debate ????

I can see now that without Autopilot or with AP in Director Mode all works the same like in the Mi-8, a short press resets the neutral point to the current stick position.

In Autopilot mode one needs to do a long press as not to fight against the Autopilot, and once at the desired stick position release the button. Like this all works well!

I also noticed that the reason for this over correcting in autopilot mode actually comes from the fact that when you fight the autopilot your stick deflection ends up to be about twice as far as when you would do it in Director Mode or when holding the trim button.

In Autopilot mode one needs to do a long press as not to fight against the Autopilot, and once at the desired stick position release the button.

To be picky, it's when the helicopter is in a STABLE attitude that coincide with what you want, then it's time to release the button, not the stick position. The stick position is actually only a tool for putting the helicopter in the attitude you want, and that is uninteresting in itself.

I do all my maneuvering with FD on and when im stable i hit the trim once and then disable the FD. The FD on does the same as the trim button, just without the trimmig. ;)

This way i can perfectly do all kinds of maneuvers without irratic unwanted moves like it is when fighting the AP channels. I really like the FD, cant imagine why not using it.

Pushing and holding the trim button deactivates AP channels so you don't have to fight against them.

Regarding FD, last time I read the manual I understood it gives some indicators (directors) to maintain a given attitude and altitude but you have to do the job yourself using the cyclic and collective sticks. I didn't understand it works like AP. Anyway why would there be 2 systems providing the same function ?

@TaFnlz : it seems you use FD as a mean to deactivate AP channels and not for its real purpose (getting some flight directors). But why not if that works for you

FD = damping on selected input channels only

Non FD = Damping channels + autopilot 'hold' functions on all selected channels

What i mean is that FD on is the same as press and holding the trimbutton. You dont need to fly after the hud symbolik while using FD on. It just switches off the Autopilot and prvides dampening on the selected AP channels like Dugong said.

When you press and hold the trimbutton, you get the same effect as far as i know. Only dampening effect without the autopilot fighting back.

The FD makes it very easy for me when i need smooth and precise control while flying very low between trees and houses for example. I really like the collidable tress, flying low makes total sense now. :)