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After trim is reset, then pressed, why does the airframe jostle?


Rangoon
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I think I understand the trim/autopilot/dampening system. I have Pitch/Bank/Yaw autopilot channels engaged. I have the trim reset, so no trim is set, no heading bug on the HUD, etc. Yet when I hold the trim button down, the airframe still jostles. Why? Is dampening also cancelled in this case? That's the only explanation I can think of for this behavior, but I thought dampening was not cancelled as long as the button was depressed for that axis.

 

When I have a trim input, I realize there are inputs by the autopilot which are attempting to maintain parameters, plus dampening. So when I hold the trim button (as if to establish a new trim position), I understand that it's no longer trying to maintain or re-establish parameters, suddenly it lets go of the controls, is no longer fighting me, and the airframe jostles. But I thought the system was still dampening while holding the trim, is it not? So when there is no trim, and no parameters the autopilot is trying to hold, and if dampening is in effect before and after depressing the trim button, why this little upset?

 

The manual references that holding the trim button cancels position signals, but doesn't mention dampening. It only mentions dampening to state that it remains in effect while in Flight Director mode. Maybe I was just wrong to assume this about the dampeners. I just don't feel like the aircraft moves while the trim button is depressed the same, loose way that it does without any autopilot channels engaged. Is that all in my head?

 

6-6 "Trimmer) button – Cancels all force on cyclic with the trimming mechanisms. When released, the autopilot will stabilize current angles of pitch, bank and yaw [T]."

 

13-3- "Pressing the “ТРИММЕР” (TRIM) button on the cyclic stick cancels the autopilot’s position signals for bank (K), pitch (T) and yaw (H) and releasing it places the angular position of the helicopter in 3D space in memory."


Edited by Rangoon
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I think I understand the trim/autopilot/dampening system. I have Pitch/Bank/Yaw autopilot channels engaged. I have the trim reset, so no trim is set, [...]"

 

Maybe the entire problem comes from the fact that there is no trim reset in the real Ka-50. "Trim reset" is a function for us sim pilots with incompatible hardware. We can easily trim the Ka-50 in a way that it's basically out of trim and, possibly, out of control.

 

In the real aircraft (and with proper force feedback sticks), the trimmed position and the physical stick position are linked. With a non-force feedback stick, there is no such link. That's why we sometimes need to use "Trim reset". That moves the Ka-50's stick to the center position - which is probably out of trim for most flight attitudes (and also the reason this should be a last resort method for newcomers; there shouldn't be any reason at all to use it for experienced pilots).

 

Yet when I hold the trim button down, the airframe still jostles.

 

Can you describe this jostling or post a video?

 

In my experience, there may be a minimal reaction by the chopper when I press the trim button, but I don't think it should "jostle" when the button is pressed down.

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Maybe the entire problem comes from the fact that there is no trim reset in the real Ka-50. "Trim reset" is a function for us sim pilots with incompatible hardware. We can easily trim the Ka-50 in a way that it's basically out of trim and, possibly, out of control.

 

In the real aircraft (and with proper force feedback sticks), the trimmed position and the physical stick position are linked. With a non-force feedback stick, there is no such link. That's why we sometimes need to use "Trim reset". That moves the Ka-50's stick to the center position - which is probably out of trim for most flight attitudes (and also the reason this should be a last resort method for newcomers; there shouldn't be any reason at all to use it for experienced pilots).

 

Okay, that I understand, sure. You're just updating a trim position to closer to neutral rather than resetting per se. I have about 4000 hours of civil helicopter time, and one of the models I have time in uses an electric trim system to remove pressure from the cyclic and there is a hat which is used to fine tune the exact position. Otherwise motors just continuously work to zero out the forces. There is definitely no "reset" on that, but it's also by nature a different approach to trim than the Black Shark.

 

But there is one other small confusion on *not* having a trim reset in reality. In the sim, not only does it simulate re-centering the cyclic and then trimming to that point, but it also actually removes the heading cue from the HUD (and from the autopilot). So is there no way to do this in the real Ka-50? I mean other than turning off the heading channel and back on again I suppose? But whatever, I'm a bit off track.

 

Can you describe this jostling or post a video?

 

In my experience, there may be a minimal reaction by the chopper when I press the trim button, but I don't think it should "jostle" when the button is pressed down.

 

Here is where I understand the jostle to come from if I'm trimmed, or in route mode, and then I hold the trimmer (to re-establish new trim/autopilot parameters): While flying on route mode, the autopilot is inputting above and beyond what you have input and how you have it trimmed. So when you hold down the trim button, the autopilot ceases to try and make the aircraft do what it thought you wanted it to do and within its 20% control authority. So if you had left cyclic input past the trimmed point, but the autopilot was inputting some right cyclic to keep you flying straight, and then you hold the trim button down suddenly that right autopilot input is released and the aircraft lurches to the left (the jostle). All that should remain is the dampening system for each channel, but no attempt to fly particular angles or a particular trajectory. Sound right so far?

 

Yet when I have no trim (trim is reset), and I am not in route mode (no trajectory set), why the jostle when I hold down trim? Other than dampening, the autopilot should not be trying to do anything for me, right?

 

However, perhaps this comes back to your point that there is really no such thing as a trim reset. So when I think I've reset the trim, and removed the trajectory and 3-dimensional position targets from the autopilot memory, in fact what I've done is RE-TRIMMED to a "neutral" cyclic position. So the autopilot is still doing more than dampening and thus the jostle is expected.

 

Whatever the answer is, I absolutely love that DCS models systems deeply like this. Not just modeling symptoms of surface-level systems, but, within reason, the systems themselves.

 

Also, thanks for linking to the Leading Edge videos in my other thread. I'm just getting back to the Black Shark after about three or four years off from it, and relearning all of this stuff. I think I recall those videos (they seem so familiar as I watch them now). Good stuff.

 

EDIT: also, the jostle I'm talking about is very subtle, but it's there. I'm not talking about some major airframe discombobulation like what happens if you just reset the trim in forward flight without following with immediate and correct inputs which equate to the trim setting you just tossed. I just mean those little sways (a couple degrees of pitch, heading, etc.) you get.


Edited by Rangoon
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The Jostle comes from less exact steering inputs by the Pilot and will get less by itself over the time. :)

 

I think it's now safe to say that we're talking about two different jostles.

 

Maybe the entire problem comes from the fact that there is no trim reset in the real Ka-50.

 

I believe this is exactly where it comes from...

 

I did a little more testing. I also found mention in the Ka-50 FAQ about how errors accumulate in the autopilot, but I think what I'm experiencing neither results from system errors nor from pilot imprecision. I think it does have everything to do with Yurgon's observation that there is really no actual trim reset as far as the aircraft systems are concerned.

 

To demonstrate: if you reset trim, three autopilot channels engaged (all but altitude hold, though it wouldn't matter really), then accelerate from a hover, holding negative pitch (holding forward cyclic), then press and hold the trim button (without releasing), the aircraft pitches forward. In another example, if you hold forward and left, then press the trim button, the aircraft banks left and pitches forward. So even though trim is reset, it's really just trimmed to a neutral position (which is rearward flight, at least with a standard combat load and the accompanying center of gravity; maybe even at basic empty weight it's the same). Therefore, when you're accelerating with forward pitch, the autopilot is trying to to slow you down because it thinks you want to fly backward (neutral cyclic). So it's putting in its 20%-authority aft cyclic while you're overriding with forward. Then when you hold the trim button down, it stops trying to get you to slow down, and only dampens, so your inputs are no longer impeded and the helicopter pitches further in that direction.

 

Of course this makes sense when I think of trim reset as TRIM TO NEUTRAL CYCLIC POSITION.

 

Maybe none of this is of interest to anyone but me, or it was obvious to everyone but me. But I'm quite sure that answers my question about why it was behaving this way after a trim reset.

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hi ,no trim problem in the real one : the ka50 's game implementation is buggy

 

??? :huh:

 

We are talking about "trim reset" which causes issues. That is a "cheat" function and not really part of the Ka-50 modelling in DCS. I don't know what the video shall show us in this regard and I also don't see where the actual trimmer logic in DCS for the Ka-50 is buggy - or even is different from what was shown in the video.

 

So, could you elaborate please?


Edited by Flagrum
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I have a question and a wish:

 

Does the autopilot physically move the controllers? Or is this all happening beneath the floorboards? I don't see the controllers move in the sim as a result of autopilot inputs, but then again I'm not staring at them while this is happening.

 

It would be really nice to have a option to view what inputs the autopilot is making; have a black overlay on the red indication box - RCTL ENTER - or something along those lines, as an option. The red diamond and lines could have black lines with a dot at the end showing how the autopilot is modifying the pilots inputs. It might really help new pilots get a handle on the trim and autopilot systems. It also might give an experienced pilot better control prediction when changing parameters. I would expect there is some way for a pilot of the real Ka-50 to feel "tuned in" to the autopilot and know what it's doing. With the electric trim that I'm familiar with, you can feel what it's doing even if it doesn't physically move any controls (again, this is different from the Black Shark's trim system, fundamentally, but similar in that you have two systems acting on the controls).


Edited by Rangoon
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hi ,no trim problem in the real one : the ka50 's game implementation is buggy
Aaaaaaaaaah taboo!! taboo!!

I still remember how many times it was said that nothing was wrong with the autopilot in those early versions of Black Shark. And one day: "hey guys, there was something wrong with the autopilot. We forgot to add the turning logic"

Since then, I prefer to remain agnostic in this ka-50's autopilot question.

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No problem with the Force Trim, the AFCS, and the Auto Pilot in the Ka-50 DCSW.

 

The problem is your joystick spring, and spring pedals, which requires it to operate the helicopter artificially.

Also, get to know how the system works, and know "move" inside and outside the 20% authority.

 

If you need to use the Reset-Trim in flight, you SHOULD NOT be flying :)

 

You must have a FFB joystick and pedals without spring, of this form can control the Ka-50 in a natural manner, similar to how operates a real pilot.

 

Greetings!

 

"If adventure is dangerous, try the routine. It is deadly."

Paulo Coelho.

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No problem with the Force Trim, the AFCS, and the Auto Pilot in the Ka-50 DCSW.

 

The problem is your joystick spring, and spring pedals, which requires it to operate the helicopter artificially.

Also, get to know how the system works, and know "move" inside and outside the 20% authority.

 

If you need to use the Reset-Trim in flight, you SHOULD NOT be flying :)

 

You must have a FFB joystick and pedals without spring, of this form can control the Ka-50 in a natural manner, similar to how operates a real pilot.

 

Greetings!

 

 

That might be, but I never said my cyclic or pedals have springs. Neither my cyclic nor my pedals have springs. And I do understand the value of a force-feedback stick (unfortunately, there isn't a FFB stick/HOTAS now that measures up in every other way BUT the force feedback aspect).

 

I am only very rarely using reset trim in actual flight. I use the condition in this thread as an example to understand better the autopilot authority and behavior, since the behavior from a neutral trim seemed inconsistent until it was explained that "reset trim" is really just "trim to neutral". It's not any different from how the aircraft starts out from a cold start. You have neutral trim. So we *all* start with a "reset trim" condition, really, unless the mission starts you in the air and generally also has a pre-set trim by the mission maker.

 

I don't have trouble flying the Ka-50 smoothly. I'm asking about the behavior of the autopilot's authority from a neutral trim position, and I think it makes sense based on what's been discussed so far. I just wrongly assumed that neutral trim was "no trim". And that the autopilot was not trying to do anything beyond dampening at that point. But it clearly is still at work.

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The AP / AFCS in the Ka-50 has 3 functions.

 

-Damping the pilot inputs. Always active.

 

-Maintain (and memorize) the attitude of the helicopter when you release the button Trim Force.

 

Herein is where most people get lost. Each time you use the Force Trim the AFCS memorizes the helicopter attitude and try to keep it within 20% of authority in the controls.

 

That is, within that 20%, the AFCS is in control, though, pilot inputs also added. When you take the controls out of that 20% is exactly backwards. The pilot has full authority, but the AFCS try out the helo attitude towards memorize the last time you made up.

 

If you use a joy spring, the system forces you to carry the cyclic to the center of this. In a maximum of 0.5 sec. If you do not this well, it will accumulate errors, and will spend much of the flight fighting an invisible ghost. AFCS.

 

0.5 sec seems very short ... No. For a mediocre musician 0.5 seconds is a long time, giving you time to play four notes, for a virtuoso musician 0.5 seconds is an eternity.

 

If you have a joy without spring, BE ACTIVATED "FFB option" in the simulator. This frees you to bring joy to the center, but will have no physical information of the center of cyclic, and also get errors.

 

In both cases, disable FD (Flight Director) switches OFF the function of "maintaining attitude", and can help, but the right thing is to understand how the system works.

 

-The Last function of AP / AFCS is navigation and targeting, and is irrelevant to this post.

 

I enclose a flight full of mistakes, but very illustrative of the use of Force Trim.

 

 

Greetings!

 

edit:

Best rereading the first thread.

 

I'll try to describe what I think he's going.

 

You take off for stationary, with well compensated helicopter. OK. In this situation you can even drop your hand out of the cyclic. AFCS has control, even if small inputs by the pilot.

 

From stationary (without compensating) gently push the cyclic (within 20%) and the helicopter starts to move forward. (0:33 in the video)

 

Now there are two sources controlling the helicopter, the AFCS and the pilot.

AFCS have in "memory" hover attitude, and the pilot is moving the cyclic forward, the helicopter receives the sum of both inputs.

 

If at this time you press the Force Trim button, you cancel the entry of the AFCS abruptly, resulting in a movement / attitude, undesired. (0:46 in the video)

 

This is independent of the control system (spring, not spring, FFB) and is simply a pilot error.

 

If in the above example, you pushes the cyclic beyond 20% of authority of the AFCS, a smooth transition to the "subtraction" of the ratio controlled by the AFCS is produced, and will have smaller amount of unwanted movement when using the "Force Trim".

 

That is, if you compensate when the attitude of the helicopter, DOES NOT MATCH, with the attitude memorized by the AFCS, you always will be a little scare.

 

Beyond that, I assure you that the AP / AFCS behaves (do not know the degree of fidelity) as expected in a helicopter with SAS / ATT AFCS.


Edited by P1KW

"If adventure is dangerous, try the routine. It is deadly."

Paulo Coelho.

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If you use a joy spring, the system forces you to carry the cyclic to the center of this. In a maximum of 0.5 sec. If you do not this well, it will accumulate errors, and will spend much of the flight fighting an invisible ghost. AFCS.

 

Thanks for taking the time to write all of this out and put these videos togther. Also, by the way, I really like your sim setup!

 

I am using very light rubber bands, and no springs, in both cyclic and pedals. As a result, the controls have very high precision and a very light feel which is akin to the control feel I am used to in real-life flying (light civil helicopters with and without hydraulics). So there is no spring-back action in my HOTAS controls. In order to zero out my cyclic and pedals, I have a button which activates a script and zeros all three axes instantaneously. Releasing trim and neutralizing my controllers happens in well under 0.5 seconds (as quickly as I can move my thumb from the release of one button to pressing another about one inch away - it's very easy).

 

And the issue of this post is not one of smooth or accurate flying while managing the autopilot/trim systems. It's a question about why the same behavior was taking place after a trim reset as predictably happens during any other trim button press. It's a question about the real system and the sim implementation. It's about exactly what happens when you press (and BEFORE YOU RELEASE AGAIN) the trim button. Not what happens AFTER YOU RELEASE the trim button. And I *think* that I have always understood both of those aspects. What I wasn't sure of was specifically what happens when you press the trim button from a default/neutral trim position or after a trim reset. The title of the thread was a bit incomplete, since I wasn't considering initially that the conditions of default/neutral were the same as after a trim reset (I just never thought about that), and I feel that the answer from Yurgon was right on in that the trim can never really, truly be "reset", so the autopilot is always trying to get the helicopter to fly the attitudes implied by and resulting from the cyclic/pedals positions, whether neutral or otherwise. Simply put, in helicopter flying, pitch attitude is airspeed control. Of course collective input also influences pitch such that up collective generally pulls the nose up and down collective drops the nose (both of which affect airspeed as you would expect, just also an accompanying increase/decrease in overall lift). In the Ka-50, as far as I can tell, neutral cyclic is a positive pitch attitude and rearward flight (or deceleration from forward flight). So as long as the pitch channel is turned on (and no task/route is set), the aircraft tries to achieve that pitch attitude. I wrongly assumed that in a neutral/default/reset trim condition the autopilot would stop trying to influence the controls except for dampening of pilot inputs (again assuming no route/task).

 

You take off for stationary, with well compensated helicopter. OK. In this situation you can even drop your hand out of the cyclic. AFCS has control, even if small inputs by the pilot.

 

From stationary (without compensating) gently push the cyclic (within 20%) and the helicopter starts to move forward. (0:33 in the video)

 

Now there are two sources controlling the helicopter, the AFCS and the pilot.

AFCS have in "memory" hover attitude, and the pilot is moving the cyclic forward, the helicopter receives the sum of both inputs.

 

If at this time you press the Force Trim button, you cancel the entry of the AFCS abruptly, resulting in a movement / attitude, undesired. (0:46 in the video)

 

This is independent of the control system (spring, not spring, FFB) and is simply a pilot error.

 

If in the above example, you pushes the cyclic beyond 20% of authority of the AFCS, a smooth transition to the "subtraction" of the ratio controlled by the AFCS is produced, and will have smaller amount of unwanted movement when using the "Force Trim".

 

That is, if you compensate when the attitude of the helicopter, DOES NOT MATCH, with the attitude memorized by the AFCS, you always will be a little scare.

 

I guess I'm a little confused now because I think what you're getting at is basically what I described in post #6 of this thread. Are you saying my description in #6 was incorrect? I feel pretty confident that I had it right in that post, but of course I might very well still not understand 100%.

 

Beyond that, I assure you that the AP / AFCS behaves (do not know the degree of fidelity) as expected in a helicopter with SAS / ATT AFCS.

 

I have never doubted the implementation of the system, especially considering the limitations of the simulation and controllers (other than FFB). I have always found ED's solution in this case to be quite elegant and certainly adequate as I sit at my computer desk. :)


Edited by Rangoon
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I'll try to describe what I think he's going.

 

You take off for stationary, with well compensated helicopter. OK. In this situation you can even drop your hand out of the cyclic. AFCS has control, even if small inputs by the pilot.

 

From stationary (without compensating) gently push the cyclic (within 20%) and the helicopter starts to move forward. (0:33 in the video)

 

Now there are two sources controlling the helicopter, the AFCS and the pilot.

AFCS have in "memory" hover attitude, and the pilot is moving the cyclic forward, the helicopter receives the sum of both inputs.

 

If at this time you press the Force Trim button, you cancel the entry of the AFCS abruptly, resulting in a movement / attitude, undesired. (0:46 in the video)

 

This is independent of the control system (spring, not spring, FFB) and is simply a pilot error.

 

If in the above example, you pushes the cyclic beyond 20% of authority of the AFCS, a smooth transition to the "subtraction" of the ratio controlled by the AFCS is produced, and will have smaller amount of unwanted movement when using the "Force Trim".

 

That is, if you compensate when the attitude of the helicopter, DOES NOT MATCH, with the attitude memorized by the AFCS, you always will be a little scare.

 

So you're saying before clicking trim, we need to first move the stick at least 21% to push past the AFCS authority? That sounds quite hard to do in practice without an indicator to show when you've done so and makes me wonder how those Russians manage to fly whilst rapidly clicking trim, when they're clearly not moving the cyclic much between clicks. I've also previously been advised that I should trim often when banking, i.e. after every 5 degrees, rather than banking 20 degrees and then trimming, which your advice seems to contradict, so I'm not sure what's correct.

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I finally took the time to come back to this thread; sorry for the delay, but I feel the topic wouldn't have warranted a short answer.

 

I have about 4000 hours of civil helicopter time, [...]

 

What do you fly? Hobby or professional? 4000 hours sounds like quite a lot (and I'm wondering why a pure sim pilot like myself answers questions to someone with much more experience with rotary wing flight; then again, although I haven't kept track, I must have dozens if not a few hundred hours in the DCS Ka-50, so I guess that's a qualification as well). :thumbup:

 

and one of the models I have time in uses an electric trim system to remove pressure from the cyclic and there is a hat which is used to fine tune the exact position. Otherwise motors just continuously work to zero out the forces. There is definitely no "reset" on that, but it's also by nature a different approach to trim than the Black Shark.

 

Wow, very different indeed! I never heard about a helicopter with a trim hat in addition to a trim button/force reset. For fine tuning, that must be pretty cool.

 

But there is one other small confusion on *not* having a trim reset in reality. In the sim, not only does it simulate re-centering the cyclic and then trimming to that point, but it also actually removes the heading cue from the HUD (and from the autopilot).

 

I just flew the Shark for about half an hour and couldn't get the heading cue in the HUD to disappear by trimming. I've tried with Flight Director on and off, with and without a selected Nav point in the PVI-800 and with and without Route Mode. Can you describe the circumstances for the heading cue to disappear?

 

On a side note, which version are you flying: the ancient BS1, the old BS2 standalone or an up-to-date BS2 for DCS World 1.2.14 (1.2.15 since a couple of days)?

 

Here is where I understand the jostle to come from if I'm trimmed, or in route mode, and then I hold the trimmer (to re-establish new trim/autopilot parameters): While flying on route mode, the autopilot is inputting above and beyond what you have input and how you have it trimmed. So when you hold down the trim button, the autopilot ceases to try and make the aircraft do what it thought you wanted it to do and within its 20% control authority.

 

That sounds like an accurate description, and I think I finally understand the jostle you describe. Yes, under these circumstances the aircraft would surely jostle.

 

I just never thought about flying it "against" Route Mode; even with Route Mode on, I try to trim the Black Shark so that it would keep flying with that attitude if I switched Route Mode off. In other terms, I try to keep the autopilot from having to fight my inputs. That way, when I hold down the trim button, there might be a tiny little bit of a jostle or even none at all.

 

Also, thanks for linking to the Leading Edge videos in my other thread. I'm just getting back to the Black Shark after about three or four years off from it, and relearning all of this stuff. I think I recall those videos (they seem so familiar as I watch them now). Good stuff.

 

I simply can't recommend them enough, I've learned so much from them! :thumbup:

 

[...] Maybe none of this is of interest to anyone but me, or it was obvious to everyone but me. But I'm quite sure that answers my question about why it was behaving this way after a trim reset.

 

I think the intricacies of the Black Shark and its systems are always fascinating and I did gain more awareness of how the trim system works in conjunction with the autopilot. Good thread! :thumbup:

 

Does the autopilot physically move the controllers? Or is this all happening beneath the floorboards? I don't see the controllers move in the sim as a result of autopilot inputs, but then again I'm not staring at them while this is happening.

 

I'm almost certain that there is no such movement in DCS Black Shark, and I think this is realistically simulated, although I'm not sure about it.

 

It would be really nice to have a option to view what inputs the autopilot is making; have a black overlay on the red indication box - RCTL ENTER - or something along those lines, as an option. The red diamond and lines could have black lines with a dot at the end showing how the autopilot is modifying the pilots inputs. It might really help new pilots get a handle on the trim and autopilot systems. It also might give an experienced pilot better control prediction when changing parameters. I would expect there is some way for a pilot of the real Ka-50 to feel "tuned in" to the autopilot and know what it's doing. With the electric trim that I'm familiar with, you can feel what it's doing even if it doesn't physically move any controls (again, this is different from the Black Shark's trim system, fundamentally, but similar in that you have two systems acting on the controls).

 

Good idea, I've often wondered about such a display myself.

 

When learning to fly the Ka-50, I soon realized there was no such visualization of the autopilot input and after a while, muscle memory kicked in and I didn't need it any longer, but you're right that it would be very helpful for new pilots.

 

The Ka-50 hasn't seen many updates in the past months, if not years, but it would be awesome if ED added this.

 

Somewhere in the back of my head I think I saw something similar in one of the other modules, but my mind might be playing tricks on me, or it might be from a 3rd party dev so that ED couldn't easily implement it anyway. In any case, it would be really helpful for new pilots, and given that (in my subjective perception) there has recently been a increase in newcomer question, it seems that the Ka-50 still finds new pilots despite being the first DCS module. :thumbup:

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What do you fly? Hobby or professional? 4000 hours sounds like quite a lot (and I'm wondering why a pure sim pilot like myself answers questions to someone with much more experience with rotary wing flight; then again, although I haven't kept track, I must have dozens if not a few hundred hours in the DCS Ka-50, so I guess that's a qualification as well). :thumbup:

 

I fly professionally in the US, these days most of my time is crop dusting in Robinson R44s and training students. Helicopters in general is one thing. The Black Shark, combat flying, sim flying, and sytems management in complex aircraft are very different from what I deal with IRL, so you're still the expert in this conversation :)

 

Wow, very different indeed! I never heard about a helicopter with a trim hat in addition to a trim button/force reset. For fine tuning, that must be pretty cool.

 

Newer R44 Ravens have hydraulics, but the older Astros typically had (still have, in many cases) this electric trim. It has two motors, one for each axis, which always drive to alleviate any pressure and effectively keep the control in place. I sometimes use the hat to anticipate what I'm about to do, or else just to "tell it" what zero force feels like if it doesn't seem to be getting it right for whatever reason.

 

I just flew the Shark for about half an hour and couldn't get the heading cue in the HUD to disappear by trimming. I've tried with Flight Director on and off, with and without a selected Nav point in the PVI-800 and with and without Route Mode. Can you describe the circumstances for the heading cue to disappear?

 

Sure, try this: Flight Director off. Pitch/Heading/Bank channels on (with or without Altitude). No task (nothing on PVI, no waypoint function, no target point function, no airbase function). No route mode (switch to center position). Now if you trim the aircraft, it will put a heading bug on your HUD. Reset the trim and the heading bug goes away. It does on mine.

 

On a side note, which version are you flying: the ancient BS1, the old BS2 standalone or an up-to-date BS2 for DCS World 1.2.14 (1.2.15 since a couple of days)?

 

I'm using the most up-to-date version of Black Shark 2, DCS World 1.2.15.

 

That sounds like an accurate description, and I think I finally understand the jostle you describe. Yes, under these circumstances the aircraft would surely jostle.

 

Indeed, and so you can understand that in most flying, this jostle is very subtle but it's still a jostle on even such small terms. Of course you can make it a large jostle by flying sloppy or not paying attention to what you're doing (or intentionally applying disagreeable inputs!).

 

I just never thought about flying it "against" Route Mode; even with Route Mode on, I try to trim the Black Shark so that it would keep flying with that attitude if I switched Route Mode off. In other terms, I try to keep the autopilot from having to fight my inputs. That way, when I hold down the trim button, there might be a tiny little bit of a jostle or even none at all.

 

I try to fly in harmony with the autopilot, too. And most of the time things are going along pretty well. I just still tend to get to 98% correct inputs and then release the trim and/or engage route mode knowing that autopilot will take care of that last 2% for me. Maybe in time I will get everything spot on (as I have to IRL, since I have no autopilot). It really makes me appreciate what the Ka-50 pilot has in this system. You still have to fly the Black Shark, but when you're task saturated, how brilliant having this system just take care of that busy work of balancing the machine in whatever flight mode you happen to be in. So, good thing for me IRL that I'm not in combat! Crop dusting can be a handful, with many systems at play in addition to flying, but it's not combat. ;)

 

I simply can't recommend them enough, I've learned so much from them! :thumbup:

 

Hear, hear. I'm still savoring the start-up videos little by little (hard to pull myself away from the Ka-50 cockpit these days unless I'm reading the manual (over and over).

 

I'm almost certain that there is no such movement in DCS Black Shark, and I think this is realistically simulated, although I'm not sure about it.

 

Okay, I figured as much. It makes sense that this autopilot input is all happening behind the panels. Still, the pilot *is going to know* what the autopilot is doing, I'm certain of this. You can't fly a helicopter and not know someone or something else is influencing your controls, even if the levers aren't physically moving in your hands or underfoot. I just can't fathom a pilot not feeling this in the aircraft's movement of course and precisely in what ways it's not doing what you're inputting however subtle the difference might be. It's a subtle machine, to say the least. That's why I wish I could see what the autopilot is doing (same reason it's so nice to have that control input box RCTL-ENT just for my own inputs). Of course the pilot know his own inputs, yet why is it helpful to have that graphic depiction? Because it's a sim.

 

Good idea, I've often wondered about such a display myself.

 

When learning to fly the Ka-50, I soon realized there was no such visualization of the autopilot input and after a while, muscle memory kicked in and I didn't need it any longer, but you're right that it would be very helpful for new pilots.

 

The Ka-50 hasn't seen many updates in the past months, if not years, but it would be awesome if ED added this.

 

Somewhere in the back of my head I think I saw something similar in one of the other modules, but my mind might be playing tricks on me, or it might be from a 3rd party dev so that ED couldn't easily implement it anyway. In any case, it would be really helpful for new pilots, and given that (in my subjective perception) there has recently been a increase in newcomer question, it seems that the Ka-50 still finds new pilots despite being the first DCS module. :thumbup:

 

Maybe someday we will get it officially. as DCS doesn't seem to be going anywhere soon (I hope!).

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So you're saying before clicking trim, we need to first move the stick at least 21% to push past the AFCS authority? That sounds quite hard to do in practice without an indicator to show when you've done so and makes me wonder how those Russians manage to fly whilst rapidly clicking trim, when they're clearly not moving the cyclic much between clicks. I've also previously been advised that I should trim often when banking, i.e. after every 5 degrees, rather than banking 20 degrees and then trimming, which your advice seems to contradict, so I'm not sure what's correct.

 

Never.

 

Never ever. This applies only to test and learn how the system works and how it affects the behavior of the helicopter.

 

I auto quote.

 

"That is, if you compensate when the attitude of the helicopter, DOES NOT MATCH, with the attitude memorized by the AFCS, you always will be a little scare."

 

Or put another way;

 

Whenever you go to change the attitude of the helicopter, you must "notify" to the AFCSsystem (Force Trim button pressing) of its intention.

 

If you do NOT do that, you will have to "fight" with the AFCS, and if the pilot inputs are within 20% of the AFCS authority, the struggle is harder.

If the maneuver induced by the pilot, is beyond 20% of the AFCS authority, it is equally important to compensate the beginning of this, for the same reason, although different mechanism, leaving 20% will also have a little surprise.

 

If you are inside / outside the 20% of authority is irrelevant to the pilot, the transition is completely transparent to the pilot. There is NO reason to "learn" which is 21% beyond testing.

 

Use of "Reset Trim" funtion is a concession to "joy of spring" users when do not dominate the use of Force Trim.

Imagine a plane flying at cruising level, imagine putting that airplane in a landing configuration by pressing a button ... ... imagine the consequences.

If you want to fly with a minimum of rigor the Ka-50 simulation, completely forget that option, is an aeronautical aberration. :doh:

 

 

I am using very light rubber bands, and no springs, in both cyclic and pedals. As a result, the controls have very high precision and a very light feel which is akin to the control feel I am used to in real-life flying (light civil helicopters with and without hydraulics). So there is no spring-back action in my HOTAS controls. In order to zero out my cyclic and pedals, I have a button which activates a script and zeros all three axes instantaneously. Releasing trim and neutralizing my controllers happens in well under 0.5 seconds (as quickly as I can move my thumb from the release of one button to pressing another about one inch away - it's very easy).

 

That's crazy. :doh: If you do NOT have a spring joy, Why you need reset the controls?

 

You must enable FFB option in the simulator. Assuming your cyclic keep the position.

 

For the pedals, you must use this MOD; (Only in the Ka-50, unnecessary in the Hip and Huey)

 

http://forums.eagle.ru/showthread.php?t=40624

 

Saludos!

 

po:

I still pending, reread your post # 6

Greetings!


Edited by P1KW

"If adventure is dangerous, try the routine. It is deadly."

Paulo Coelho.

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Why do you need to REST TRIM 1st place ?

 

The problem with it is hard to fix, it's easier to evade the problem.

 

Enable R-CTRL + RETURN Joystick view.

Manually recenter your stick by looking at that graph. I never ever needed this stupid recenter trim button, it just messes up your style and may brake your blades if you hit that button with enough IAS.

 

The Ka is a smooth flyier, even when fast she likes smoothness. Toss her around and you will see all sorts of bad things, blinking AP's, messed up trim (pilot input error) and such. Walk her with brains, not muscles.

 

Bit

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Why do you need to REST TRIM 1st place ?

 

The problem with it is hard to fix, it's easier to evade the problem.

 

Exactly. As I mentioned already in this thread, I only very rarely use the reset trim. That's not the point of the thread. The point is "why does the autopilot behave the way it does AFTER a trim reset, then a trim press and hold" which could also be stated "why does the autopilot behave the way it does FROM A DEFAULT TRIM position" like at the start of a mission, cold start on the ramp, if you don't pre-trim prior to taxi/takeoff. So the question isn't "why do cold-start missions start you with neutral trim" is it? It's about why does the autopilot behave the way it does from this condition.

 

And, as I've come to understand it throughout this thread, it's because there is no such thing to the autopilot as a "reset trim" or a "default trim" such that it isn't always trying to return to the parameters of that condition (which it is).

 

So the thread isn't about trim reset and whether to use it or not. That's relevant as a general discussion, but not exactly here since the topic is about further understanding the system. I'm sorry if the title doesn't make that totally clear, but I think the posts up to this point do. I think it's a very minute but fascinating detail.

 

Enable R-CTRL + RETURN Joystick view.

Manually recenter your stick by looking at that graph. I never ever needed this stupid recenter trim button, it just messes up your style and may brake your blades if you hit that button with enough IAS.

 

The Ka is a smooth flyier, even when fast she likes smoothness. Toss her around and you will see all sorts of bad things, blinking AP's, messed up trim (pilot input error) and such. Walk her with brains, not muscles.

 

I certainly do agree the Black Shark is a smooth flyer and as indicated don't have any complaints about the bird, the autopilot system, nor the flying. It's always been about the behavior, which at first I thought was peculiar, but now makes perfect sense.

 

I routinely fly with RCTL-ENT overlay up and constantly reference it. It's very valuable in this case due to the simulation being different from reality. In reality, you never wonder where your controls are, even with a behind-the-panels autopilot influence. But in the sim, where you can't feel the kinesthetic/postural feedback of your body and the airframe, let alone the control positions (without FFB), that overlay is a great tool.

 

Why use the trim reset? First of all, to test this behavior. Also, from time to time, far from every flight, maybe every few flights, I find that it's useful (or simple, easy, maybe even a little lazy). The situations where this is the case, however, are odd and unpredictable. It's a nice option to know is there in this imperfect solution harmonizing simulatED with simulatOR.

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That's crazy. :doh: If you do NOT have a spring joy, Why you need reset the controls?

 

You must enable FFB option in the simulator. Assuming your cyclic keep the position.

 

I can imagine it sounds crazy, and it's a little difficult to describe. I use CH controls because I really like the powerful software and scripting capabilities, plus everything is integrated (FighterStick, ProThrottle with FrankenPotato mod, ProPedals, MFP). I don't like springs, though, so I took them out of the Fighterstick and ProPedals and replaced them with weak rubber bands. If CH made a FFB stick and pedals (heck, and throttle) that worked with their Control Manager software and all devices together like this, I would have that. But they don't. So no springs, but also no force feedback. So the stick feels very much like what I'm used to in real helicopters, except there is no feedback of course - what matters to me is that the sensitivity and the precision are right. I just need to cope with the fact that the stick won't return itself to center, nor will it hold itself in place like a FFB stick. So I have a script/button system where I can just tell it to either hold its last position while I let go of the stick, or go to center. Then when I'm back ready to manipulate it, I tell it so.

 

It's a very elegant and nice system, for me. Got rid of my springs for much higher precision and subtlety (like a helicopter should feel), but kept my favorite controllers/software. So for me to trim the Black Shark, I press/hold trim, position control inputs, release trim, and immediately zero my controllers (cyclic and pedals) with the press of a button. I can then either re-enable if I need to input right away, or I just let go and the controls are at neutral and the DCS BS2 trim system is happy. Then, when I want to hand fly, I just center my controllers and press a button - I'm back in action. I never had to deal with physically centering within 0.5 seconds. In fact, I use the option to wait for a center input before allowing further inputs (CENTRAL POSITION TRIMMER MODE), so that part isn't important. That mode keeps everything nice and clean, and the process is easy (the scripting part was not! :wallbash: ;) )

 

I have time in all the Robinsons, Bell 206 Long Ranger, OH-6 Cayuse, and Brantly B-2B. Not a lot of airframes, by any means, and no Black Shark time, but these aircraft all felt far more similar to each other than different. So I'm assuming the Black Shark is a subtle machine with finesse in the controls. As such I like this setup, but it's still no FFB, unfortunately. Some day. It's a matter of priorities and I'm happy with this compromise.

 

For the pedals, you must use this MOD; (Only in the Ka-50, unnecessary in the Hip and Huey)

 

http://forums.eagle.ru/showthread.php?t=40624

 

That mod isn't right for my setup. I like having the trim system the way it is. I always center my pedals (just like I do my cyclic) before I start hand/feet-flying again. It's just a habit. So I don't have problems with the pedals like what the mod tries to solve. Seems like a cool solution, though, for those who do! :)

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I fly professionally in the US, these days most of my time is crop dusting in Robinson R44s and training students. Helicopters in general is one thing. The Black Shark, combat flying, sim flying, and sytems management in complex aircraft are very different from what I deal with IRL, so you're still the expert in this conversation :)

 

Haha, okay. :)

 

This is probably not quite the right place, but since you have a lot of real life flying experience, I'm sure a lot of us would appreciate some fun stories and/or instructive comments from you in the Military and Aviation part of the forum, if you have the time for it. :thumbup:

 

Newer R44 Ravens have hydraulics, but the older Astros typically had (still have, in many cases) this electric trim. It has two motors, one for each axis, which always drive to alleviate any pressure and effectively keep the control in place. I sometimes use the hat to anticipate what I'm about to do, or else just to "tell it" what zero force feels like if it doesn't seem to be getting it right for whatever reason.

 

Good to know, thanks!

 

Sure, try this: Flight Director off. Pitch/Heading/Bank channels on (with or without Altitude). No task (nothing on PVI, no waypoint function, no target point function, no airbase function). No route mode (switch to center position). Now if you trim the aircraft, it will put a heading bug on your HUD. Reset the trim and the heading bug goes away. It does on mine.

 

Okay, now I was able to reproduce it. The one thing I didn't try was "Trim reset". :)

 

So, yeah, happens to me as well, but I'm at a loss for an explanation. Maybe this is a bug in DCS or it is expected behavior on behalf of the devs, but since AFAIK "Trim reset" doesn't exist in the real aircraft, I assume this is a peculiarity in DCS.

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Ok Rangoon, I've finally come to understand. Sorry I have diverted the topic.

His statement that does not use springs has confused me.

 

About the "bug" HUD completely unknown, but as already mentioned, is not a real function. I can only add that the way to reset the AP is compensating, (Force Trim release).

If you use the method of "CENTRAL POSITION TRIMMER MODE" is practically impossible to accumulate errors, and this function should not be necessary. (Reset Trimm)

 

Otherwise, the more reason if you are professional, although its setup lets fly perfectly the Ka-50, ok, but somehow always have a point of frustration because this not controlling the helicopter naturally, I hope can someday get a FFB cyclical, today is the best option.

 

Greetings!

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"If adventure is dangerous, try the routine. It is deadly."

Paulo Coelho.

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Ok Rangoon, I've finally come to understand. Sorry I have diverted the topic.

His statement that does not use springs has confused me.

 

About the "bug" HUD completely unknown, but as already mentioned, is not a real function. I can only add that the way to reset the AP is compensating, (Force Trim release).

If you use the method of "CENTRAL POSITION TRIMMER MODE" is practically impossible to accumulate errors, and this function should not be necessary. (Reset Trimm)

 

Otherwise, the more reason if you are professional, although its setup lets fly perfectly the Ka-50, ok, but somehow always have a point of frustration because this not controlling the helicopter naturally, I hope can someday get a FFB cyclical, today is the best option.

 

Greetings!

 

Thanks for the reply. I think the system is clear now.

 

And in fact, after rethinking it, today I decided to try without the "CENTRAL POSITION TRIMMER MODE" and as of now I like it better without it. Since I can zero my controls with the button, I don't have a problem with the timing, and there have been a few "mis-clicks" on my part here and there where my trim press was prematurely released, resulting in a frantic couple of button presses on my HOTAS script to get it right again. Without centering force, it can sometimes be a bit challenging finding the precise neutral point on the cyclic, which is what the sim is looking for to give me back control. When all is fine, there is no panic, but in the wrong situaiton I've gotten confused under stress and had some near misses. Now I just zero out if the trim was done right, and if not, at least I'm still on the controls.

 

I do hope CH is secretly working on new controllers, especially a FFB setup (all controls, even collective). What a joy that would be (no pun intended). In general, I hope FFB makes a comeback. It was a real thing in the past. Seems like lately there is a renewed interest? And new products.

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I do hope CH is secretly working on new controllers, especially a FFB setup (all controls, even collective). What a joy that would be (no pun intended). In general, I hope FFB makes a comeback. It was a real thing in the past. Seems like lately there is a renewed interest? And new products.
I've tried to fly the ka-50 without FFB and is so awkward... But I've also tried to fly the A-10C without FFB, and despite my X-52 being far superior in terms of precision, when you feel how the force in the stick disappears as you trim the aircraft, that is so rewarding, that I prefer my MSFFB2 over anything else.

Unfortunately there is almost no market for consumer joysticks with decent FFB. And then they are not used to their full potential (how many sims are there doing the most obvious application to FFB joysticks, that is, proper force trimming?).

Look at the G940, no longer available new :(

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