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rudder trim runaway

Maxthrust

By Maxthrust
in Bugs and Problems

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ARM505

ARM505

Posted
Posted

I wouldn't call it 'trim' as it's not really ending up moving one way or the other and staying there, but the rudder is definitely twitching from side to side, yes.

It's like the yaw damper is on steroids, and is constantly trying to compensate for the slightest yaw, even caused by tiny little bumps on the ground.

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MAXsenna

MAXsenna

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Posted
55 minutes ago, ARM505 said:

I wouldn't call it 'trim' as it's not really ending up moving one way or the other and staying there, but the rudder is definitely twitching from side to side, yes.

It's like the yaw damper is on steroids, and is constantly trying to compensate for the slightest yaw, even caused by tiny little bumps on the ground.

And wind it seems. 

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gulredrel

gulredrel

Posted
Posted
2 hours ago, ARM505 said:

I wouldn't call it 'trim' as it's not really ending up moving one way or the other and staying there, but the rudder is definitely twitching from side to side, yes.

It's like the yaw damper is on steroids, and is constantly trying to compensate for the slightest yaw, even caused by tiny little bumps on the ground.

Noticed this yesterday too. Reached the parking spot and had a look at the trim gauge. It was far left. Needed to reset the rudder trim for the sortie after refueling. Don't think it's a bug, but a bit exaggerated I guess?

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Maxthrust

Maxthrust

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seems like a bug reproducible on my end. I've been practicing crosswind landings; for some reason rudder trim is way off the centre each time after I land.

5 hours ago, ARM505 said:

I wouldn't call it 'trim' as it's not really ending up moving one way or the other and staying there

that's exactly what is happening. can you try a crosswind landing then check your rudder trim when you stop?

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IvanK

IvanK

Posted
Posted (edited)

I have noticed a tendency for the aircraft to veer Left/Right after landing with my pedals central/neutral. Looking at this further, you can see the  pedal actually displaced. The Flight Controls display also indicates about 1/3 rudder displacement. A quick pedal cycle does not fix it. However if you then centre it with rudder trim everything returns to normal. So there is something strange going on here.

YAW/SLIP switch may be a player. in the Up position which is normal the Damper system is in the anti slip mode so it will both damp out yaw perturbations and also centre the slip ball. In this mode Rudder trim is deactivated in flight anyway (it is in the sim too which is correct).... which begs the question why can we centre the pedals with rudder trim on the ground with the Slip switch in the Slip switch position. Seems on the ground Rudder trim is always active. (The Flight manual is a little vague here.). So to me it seems there is some random rudder trim thing happening.

In the YAW mode (middle) position) it simply acts as a Yaw damper.

Now a bug that is present in the F1 is any Yaw damper input is being transmitted back to the pedals ... it shouldn't, damper inputs should just happen without physical feedback to the pedals. The flight manual specifically states this.

Perhaps there is something odd happening here that is causing this odd behavior on the ground. That is a random rudder trim input displaces the pedals which then gets transferred through the nose wheel steering system and appears to the pilot as an uncommanded input and directional PIO's ensue.

So maybe try with the Anti Slip Yaw switch in the centre or YAW mode and see what happens .... Off to test 🙂


Edited by IvanK
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IvanK

IvanK

Posted
Posted

Trolling deeper through the Flight manual found a couple of interesting things. ANTI SLIP is actually done by automatic rudder trim.

The ANTI SLIP system is deactivated by any pilot rudder input. So it cant interfere with pilot commanded rudder.

 It is also deactivated by  Oleo compression (Weight on wheels) . So on the ground the ANTI SLIP function SHOULD not work. I think this is the crux of the issue ... its still doing its thing on the ground then the nose wheel steering amplifies it. This oleo compression cut out  is not in the text portion of the manual but in the Rudder system schematics.

So given what we are seeing in the sim is a Rudder trim input that is causing the mayhem I am firmly of the belief that the cause is erroneous inputs from the ANTI SLIP system on the ground. Interestingly I have noticed some tendency to drift Left o Right on take off... thought it was was just me, but now think it might be a similar thing.

Will investigate further and report in the appropriate Test areas.

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IvanK

IvanK

Posted
Posted

Done some testing.

1. You can get random Rudder trim take off input on Take Off

2. On landing you can get random rudder input on short final then after landing need rudder trim to centre the surface.

3. If you deselect ANTI SLIP by selecting the switch to the Middle YAW position ... all this goes away, things are far more comfortable on the landing rollout.

Conclusion: ANTI SLIP Rudder trim input is occurring on the ground ... it shouldn't.

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gulredrel

gulredrel

Posted
Posted (edited)

I can confirm these result. Did a couple of take offs and landings with the switch in up and middle position.

ANTI SLIP / YAW switch in up position, rudder trim occurred on take offs and landing.

Had a slight left to right crosswind and the rudder was trimmed to the left... not comfortable on landing roll out.

Switch in the middle position, no rudder trim.


Edited by gulredrel
typo fixed
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  • 2 weeks later...
Joe1978

Joe1978

Posted
Posted
En 6/9/2022 a las 23:35, IvanK dijo:

Reported in the testers area.

Suggested Work around for now. Take off and Land with ANTI SLIP/YAW switch in the middle YAW position.

Once airborne select it UP to the ANTI SLIP position.

Feedback in this thread would be appreciated.

Will we have this problem solved for the next update?

At the moment I can land/take off perfect with your recommendation but.. 😞

Asus Rog Strix Z390F, i9-9900K, 64GB Crucial DDR4/3300, RTX3080, NVMe M.2 980 Pro 1T x2, SSD Evo 860 1T x2, Seagate Barracuda 1T, Seagate Barracuda 6T, HP X32C, HP Reverb G1

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DST

DST

Posted
Posted (edited)

Ok, had rudder issues last night, but not on ground. Any rudder input while flying resulted in rudder jumping completely unpredictable from side to side, then it ended up staying far off from the middle position. I really don't get what caused this, as I had no problems the last times I flew with F1. So I'm not sure if this refers to the problem described in this thread? I also had warning lights "LACET" und "DIR" going on, they seem to be rudder-related, what does that mean?


Edited by DST

I7 8700K 3.7 GHz 32GB RAM NVIDIA RTX 3080 Rift S

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Joe1978

Joe1978

Posted
Posted

The problem exists on both, but in the air it´s "less" noticeable. Observe the pedals from time to time and you´ll see that their position changes

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Asus Rog Strix Z390F, i9-9900K, 64GB Crucial DDR4/3300, RTX3080, NVMe M.2 980 Pro 1T x2, SSD Evo 860 1T x2, Seagate Barracuda 1T, Seagate Barracuda 6T, HP X32C, HP Reverb G1

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