[REPORTED]Pitch Excursions while using Trim Release

[M1Combat]

"If you are trying to help, you could actually perform some tests yourself, and post the results.

 

I would but I've been super busy for the last few months and I decided that if I could offer some insight into how to isolate the cause I could speed the process. More heads are better than less :). My suggestion to do so was to be certain that the trim was derived from a super stable flight envelope. It was that simple... but as soon as I didn't just say "Oh yeah.. a bug for sure" then RAnma just jumped my shit and refused to actually think about anything I said. I continued to try to explain in an effort to get the damn thing tested :). Also I don't use FFB... Which I mentioned as a reason as to why I didn't provide the tests myself.

 

As soon as I said anything regarding "maybe it's a bug, maybe it's not" it became very difficult to get through to various folks due to them just deciding I was simply trying to say "Nothing to see here... Move along"... but I wasn't. The motorcycle example is quite relevant. It does require that you know a little about unstable self righting vehicles... but it's pretty simple if you just take a look at cited references or read my explanations. I can't control someone else's mis-calculation of what my intentions are... and I certainly can't control their feelings that I'm trying to prove I'm smarter than they are... I mean seriously :)... WTH?

 

Anyway... If it's a bug, and it's starting to seem that way... I'd love to see it fixed :). As I said the Shark is my favorite Sim toy :).

Edited October 24, 2019 by M1Combat

[heloguy]

Any update is on this from the devs? I pm’ed Nineline a couple of weeks ago, and he said thanks, and it would get looked at.

[heloguy]

Joystick With No Springs or FFB trim bug

 

I thought I'd start another thread on this, as the original narrowed this bug down to a problem with this particular trim method.

 

If you use the trim method mentioned in the title, there is an uncommanded pitch down when you depress the cyclic trimmer switch that increases the longer you hold down the trimmer switch. It can be arrested by manually applying aft cyclic, but definitely shouldn't be there in the first place. When the trimmer is released, the nose pitches up (again, uncommmanded) seemingly at the same magnitude of the uncommanded down pitch while the trimmer button was held.

 

This seems to only happen when using the Joystick with No Springs or FFB trimming method, and while the Pitch Attitude autopilot channel is on.

 

Original thread where we worked through narrowing down the bug is here: https://forums.eagle.ru/showthread.php?t=252975

[BIGNEWY]

Hi

 

merge threads

 

thanks for the PM, can I ask you to do a very short track replay showing this behaviour and I will take a look

 

thank you

[heloguy]

Big Newy,

 

Thanks for the reply. I attached two tracks, one using the 'Joystick with No Springs or FFB' option, and one with the Default Trim option. I used the same stick for both tests, a Brunner CLS-E, but I turned off all hardware trim on my stick. Basically, this means it acts like a normal spring to center stick, no different than a Warthog, Gunfighter, T-50, etc. For both tracks, FFB is unchecked in the Misc options.

 

In the track with trim set to 'Joystick with No Springs or FFB,' I take off, get the aircraft straight and level (with the pitch excursions, it takes a second or two to let it settle down), and then depress the cyclic trimmer. On the first press, you'll see from the controls indicator, that I don't move the controls, but the nose pitches down quite a bit while the trimmer is held down. I manually move the controls to arrest the rate of descent, and get back to straight and level with the trimmer released. This time, I depress the trimmer, and the nose pitches up while the trimmer is held down. I release the trimmer, get it straight and level, and try again. What seems to be happening is it alternates between pitching up, or down while the trimmer is depressed, opposite of the time before.

 

In the track with trim set to Default, I take off, get the aircraft straight and level using the trimmer. Once straight and level, I depress the trimmer multiple times without moving the controls for various amounts of time, and get little to no excursions. Really any movement there, is probably me moving the stick a tiny bit. Nothing like you see in the track using 'Joystick with No Springs or FFB.'

 

I didn't try it in the track, but if you look back through the thread (I know, it's a little messy as we tried to nail down exactly what the issue was), the bug seems to disappear if you turn the pitch attitude hold off when using 'Joystick with No Springs or FFB.' Of course, this isn't ideal, because now the damping, and stabilizing effects of the autopilot are not in effect.

 

Whatever the problem is, it seems to be specific to using the 'Joystick with No Springs or FFB,' and the pitch attitude hold function.

Ka-50 Trim Bug Test NoSprFFB.trk

Ka-50 Trim Bug Test DefaultTrim.trk

[BIGNEWY]

Thanks I will take a look

[Aviators]

good :) we wait a answer ;)

[BIGNEWY]

Hi all

 

I have reported this to the team for further investigation.

 

Thank you

[heloguy]

Hi all

 

I have reported this to the team for further investigation.

 

Thank you

 

Great news, thanks!

[BIGNEWY]

Ok this is a bug, and it is reported, but I can not give an ETA on a fix currently.

 

Thanks

[heloguy]

Thanks for the update Big Newy. Glad it's at least known, now.

[Aviators]

Great!

[blunt_waco]

I'm not sure if this is related.

 

 

Holding trim or using flight director control and trim, the ka-50 never stays at the angle I wanted to be after I let go the trim button.

 

 

For example, I pitch down holding trim, stabilize it then let go the trim button. The chopper would keep descending even though I stabilized the chopper at VVI Zero.

 

 

Is this what you guys are describing? or what I'm experiencing is user related issue?

[Holton181]

I'm not sure if this is related.

 

 

Holding trim or using flight director control and trim, the ka-50 never stays at the angle I wanted to be after I let go the trim button.

 

 

For example, I pitch down holding trim, stabilize it then let go the trim button. The chopper would keep descending even though I stabilized the chopper at VVI Zero.

 

 

Is this what you guys are describing? or what I'm experiencing is user related issue?

Sounds like the same issue

[heloguy]

I'm not sure if this is related.

 

 

Holding trim or using flight director control and trim, the ka-50 never stays at the angle I wanted to be after I let go the trim button.

 

 

For example, I pitch down holding trim, stabilize it then let go the trim button. The chopper would keep descending even though I stabilized the chopper at VVI Zero.

 

 

Is this what you guys are describing? or what I'm experiencing is user related issue?

 

If the helicopter keeps pitching down, then it may be related. If the helicopter maintains pitch, and descends, it’s more than likely because you haven’t adjusted the collective to maintain your altitude for your given pitch setting. Straight and level in a helicopter is all about balancing your control inputs.

[heloguy]

Any update on this? Any chance it will be fixed for BS3?

[Taz1004]

I'm not sure if this is related.

 

 

Holding trim or using flight director control and trim, the ka-50 never stays at the angle I wanted to be after I let go the trim button.

 

 

For example, I pitch down holding trim, stabilize it then let go the trim button. The chopper would keep descending even though I stabilized the chopper at VVI Zero.

 

 

Is this what you guys are describing? or what I'm experiencing is user related issue?

 

Try testing this. Fly level with trim held down WITH collective at max. Then release. Does it pitch up?

Then fly level with trim held down but this time with collective at about 20-30%. Then release. Does it pitch down?

Again, do same thing but this time, with collective at in between like 60-70%. Does it hold steady?

 

If this is happening, your pitching is coming from your collective. Which I believe is normal but I'm no real Blackshark pilot so I'm not sure if this is expected behavior.

 

Should the trim button compensate for this pitching from collective too? Again, I don't know but if above is what's happening, then it's your collective.

[kingpinda]

Bump. Bug still in effect.

 

I cant help but wonder. There was an autotrimmer function for a couple of months and then it supposedly dissapeared again. Reticuli talked about the autotrimmer and that it was a bit bouncy in a few modes and especially so in the stick with no springs no ffb option.

 

Could it be that autotrimmer was removed but some code still lingers and especially so with the stick no spring no ffb setting?

 

Dear ED, your new AutoTrimmer option is problematic for the Black Shark - Bugs and Problems - ED Forums (eagle.ru)

Edited February 20, 2021 by kingpinda

[fodell]

Hi

 

merge threads

 

thanks for the PM.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

1921681001       19216811

Edited June 3, 2021 by fodell

[BIGNEWY]

Hi all, 

a fix for this was included some time ago, but I overlooked it, 

please let me know how are getting on, have you noticed a difference?

thank you

[heloguy]

On 11/19/2021 at 4:04 AM, BIGNEWY said:

Hi all, 

a fix for this was included some time ago, but I overlooked it, 

please let me know how are getting on, have you noticed a difference?

thank you

@BIGNEWY, sorry it took this long to take a look back at this.  In the middle of a move, but just gave it a shot.  I've since moved on to using Chuls's BrunnerDX w/Arduino adapter so my Brunner has actual FFB effects, but when I reset back to using hardware trim with the Joystick without Springs or FFB option, low and behold, the pitch oscillations are gone.  Looks like you guys have it solved!  Thanks!