Engine roughness and power loss when in IMC

[Oliver PB]

Hi there, 

I've just downloaded the SR22 G1000 and am mostly enjoying it, however, whenever I set the outside weather to anything IMC (in any sort of clouds/fog), the engine instantly, runs incredibly rough with the manifold, fuel flow, RPM and % Power fluctuating wildly. I've made sure the OAT is well above zero so it shouldn't be some sort of prop icing simulation but all the de-ice stuff doesn't help either. Even when I switch back to VMC after that, the engine stays rough. I fly the 22 IRL so it's not (or at least shouldn't be) an engine mismanagement issue.

Anyone got any ideas?

[Coop]

I'm guessing this is due to performance limitations on your computer. I can't say this for certain without knowing the CPU usage, FPS, and specs of your machine. When clouds are rendered in X-Plane, CPU and GPU usage increases (potentially dramatically based on specs), causing FPS to decrease. The saturation of CPU usage prevents our engine physics model from running at full speed thus causing engine roughness. 

[Oliver PB]

That is probably it, considering I'm running on a Macbook Pro. Do you know if an external GPU would be able to help with XPlane?

[Coop]

Yes. I do nearly all my development work on a MacBook Pro 16" with a RX 5700XT EGPU

[GerdS]

[GerdS]

Hi Guys,

I have the same problems with the SR22 as Oliver describes: the engine power pushes up and down in an oscillating
cycle of half a second bucking and shaking the whole aircraft, let me call it the ghost.
It appeared mostly in high throttle conditions, but not always.
Interesting to read that it would appear only in IMC -
I mainly flew in scattered weather, but with your information I took some examinations and I can confirm.

On the picture you can see, the approaching clouds descended the FPS significantly and at 15 the ghost appeared.
Since I mostly fly in 3D cockpit view, I don't really notice the weather change,
but the cockpit-FPS decreased in the same way. That surprised me,
because from my experience the FPS in cockpit-view are mostly higher than those in environment-view.

Coop, about the root cause you said something  "performance limitations on your computer."
Well, I have an
- Intel-CPU i9-9900K with 8 cores running XP with 4.8GHz and a 16GB Main-RAM
- Nvidia-GPU GTX1070TI with 8GB-RAM
Do you think that isn't enough for your Torquesim SR22 1.2.2?

[Coop]

1 hour ago, GerdS said:

On the picture you can see, the approaching clouds descended the FPS significantly and at 15 the ghost appeared.
Since I mostly fly in 3D cockpit view, I don't really notice the weather change,
but the cockpit-FPS decreased in the same way. That surprised me,
because from my experience the FPS in cockpit-view are mostly higher than those in environment-view.

Coop, about the root cause you said something  "performance limitations on your computer."
Well, I have an
- Intel-CPU i9-9900K with 8 cores running XP with 4.8GHz and a 16GB Main-RAM
- Nvidia-GPU GTX1070TI with 8GB-RAM
Do you think that isn't enough for your Torquesim SR22 1.2.2?

That CPU should definitely be sufficient, but isn't just an isolated single variable. Performance depends on lots of variables, including:

• X-Plane graphics settings
• Scenery and other plugins in-use
• Other software running on the computer

If the CPU is saturated and the physics thread is blocked from running at full rate, the engine will stutter.

[GerdS]

Thanks for your response, Coop,

but I'm not really convinced of your claim "the CPU is saturated and ..."  to be the root cause, because the CPU runs with only 25% load.
I closed all other software such as Firefox, GIT, third party weather, or any other tools,
but I can't notice a change in that 25% load number.
In the picture you can find as well a screenshot of the plugins. So, let me know, if you guess which could be responsible.
The scenery is standard laminar. As you can notice in my picture from Nov/17th there are only a few buildings; hence no challenging scenery.

 

[GerdS]

... instead of the cpu, the gpu has significant more load, around 90%, 10% less with a RTX 2080Ti card.
So for my feeling, it has something to do with the Graphics settings!

 

[GerdS]

Based on my experience the root cause is close to "clouds", as Oliver already mentioned. So I played a bit with the graphics levers.
"Number of World Objects" doesn't change anything. It mainly controls the density of the groundbuildings.
"Visual Effects" does something:
The screenshot with the low 15 FPS from Nov/17th was taken with 75% setting (No 1 on the picture).
The screenshot with the well 27 FPS from Nov/23th was taken with 50% setting (No 2 on the picture).
This leads to picture No 3 with 27 FPS, but somewhere along the way from POM to SAGER iaf (Aproach-KSNA-I20R) its engine starts stutter again!
How can you explain that? Still with CPU-Performance?

[Coop]

Which GPU is installed for pictures 1, 2, and 3 in your last post?

The engine model, assuming the engine isn't damaged (you can try performing maintenance via the SR22 Maintenance tab), as it only approaches near clouds, this signifies significant performance anomalies with the machine. Based on the screenshot sent, it does seem that the machine is GPU limited. Based on both GPU options, even the 1070 should be sufficient.

If you can, send over a log.txt file from the sim from when it is doing the stuttering and that should help give a better picture on what is going on.

[GerdS]

The RTX 1070 Ti GPU is installed for all the documentation.

To your assumed engine damage, I can tell you that on the first flight with stutter I didn’t discover any abnormalities in maintenance report.
Today there is a report which should to be cleared and adjusted, before we continue with the examination around the stutter issue, o. k.?
In almost all of the 7 Inspection parts I found:
“The following services needed to be performed:
ENGINE ENTRIES
SYSTEM ENTRIES”
The history I found in …/Output/SR22/logbook

But I don’t find anything about “ENGINE ENTRIES“ in the documentation how to fix.
Where can I find a documentation about that?
But I found 3 entries about that in this forum. Let me first see, what’s going on there …

 

[GerdS]

1. Issue with Engine Oscillation SR22 G1000 After Take Off:
Not really something new, but that my stutter appears as well already on the first flight after Take Off without clouds ... (interesting ...)

2. CHT overheat issues with 1.2.1 Release:
Coop: "That is what it shows when there isn't anything being caught on the inspection (nothing under Engine Entries or System Entries)"
mtbparker: "Ah!  Ok.  I was interpreting it to mean there might be something in the engine intakes."

That is my interpretation as well, but if there hasn't anything to be done, isn't it a bit misunderstandable?
If I find the note "Replaced fuel filter element" that tells me: somebody has already replaced the fuel filter system.
But what is the sense of that for me? If I would find: "fuel filter element to be filled" it has an appeal function with an action for me.
If fact, that could be a reason for stutter, when the fuel filter is congested. Would be a good programmable aspect in future!
Further to me:
Any kind of leaning, pitot heat switch or ICE switch doesn't change stutter ...
I always used SR22 so far, not SR22TN.
Versioncheck: "TN_Record.txt" is empty, "TN_State.txt" has information; both files are dated from the first use with Vers 1.2.1.
No difference found between both versions.

3. Oxygen Switch not working
Nothing what can help me.

Summary:
1. stutter problem: no further help found
2. maintenance: meanwhile I’m convinced that “The following services needed to be performed:” tells me more or less, that there has already been done something, hence no appeal for me.
If I had been prompted to do something, I would expect the word need in present tense not in past.
To get your clear opinion, Coop, I’ll attach my latest SR22 logbook.
Do I have to do something for engine to repair, and if yes, what and how?

 

SR22_logbook_20211125.zip

[Coop]

You can try deleting NA_Record.txt and NA_State.txt to reset the aircraft.

[GerdS]

Before deleting NA_Record.txt and NA_State.txt:
“Unfortunately,” I couldn’t reproduce the stutter even with increasing IMC intensity from SCT, over BRK to OVC. I started the flight both with running engine and cold and dark last week and today, but couldn’t reproduce a similar situation, except, when I lean too much. But that stutter is significant higher than the coincidentally happened one, which I described above.

After deleting NA_Record.txt and NA_State.txt:
The new NA_State.txt contained different text, but the maintenance information kept the same.
Regarding stutter that change delivered no additional information.

I’m going to continue my training with that aircraft for a while, and since I can capture a new stutter, I’ll post the log.txt.

Gerhard.

[FelixG]

Same here, deleting the abovementioned files, overhaul etc. didnt help. I have a Ryzen 9 and a GeForce RTX 3090, should be decent!

[Coop]

36 minutes ago, FelixG said:

Same here, deleting the abovementioned files, overhaul etc. didnt help. I have a Ryzen 9 and a GeForce RTX 3090, should be decent!

Yes, but also you can still easily outpace any computer hardware if you push XP11 settings to the max along with high-end addons. I can take a look if you can provide:

• log.txt from a flight with the SR22
• Attach the contents of X-Plane 11/Output/SR22 (or /SR20 for the SR20s). Probably best to attatch as a zip file.
• Video of what you are experiencing
• Screenshot of your X-Plane rendering settings

[grodey]

Hi, I fly the real SR22T and use this product for IFR training. Version 1.22 worked well enough, 1.3 is broken with the unflyable power surging described above. I would like to re-load ver 1.22 please. I have the zip file and windows loader, but it can't access the 1.22 files on x-aviation site. Please help, thanks.

Geoff Rodey

 

[Coop]

On 3/23/2022 at 2:10 PM, grodey said:

Hi, I fly the real SR22T and use this product for IFR training. Version 1.22 worked well enough, 1.3 is broken with the unflyable power surging described above. I would like to re-load ver 1.22 please. I have the zip file and windows loader, but it can't access the 1.22 files on x-aviation site. Please help, thanks.

Geoff Rodey

 

There shouldn't be any major difference in the performance between these two versions, I'd recommend making sure that your X-Plane settings aren't overloading the computer. Something you can also try is manually removing the aircraft (in X-Plane 11/Aircraft/X-Aviation) and preference files (In X-Plane 11/Output/SR22) and then re-running the installer.

[GerdS]

Hi CooP,

 

I’m back again with some new stutter experiences.

I loaded real weather situation with FS Global Real Weather (X-Plane 11 Edition), did my trials until I found the Antialiasing slider as the most effectful lever to influence the stutter.

I stored the flight and loaded it today again, but without the weather tool.

Weather situation:

Wind  320/7, Visibility 9 -RA, SkyCon 900FEW, 1100BRK, 2700SCT, Temp 09/08, Area QNH1020

The aircraft is at 6000ft totally within clouds, different as above in my post on November 24, 2021, where I was slightly below the cloud bottom limit, where I had still 25 FPS during stutter.

So, the Visual Effects didn’t have some effects, because in the outside view everything is white.

[GerdS]

.... The Graphics Setting of the Flight

-  starts with Setting |HDR anti-aliasing set to 1 at 25 FPS: no stutter

-  changes with Setting |HDR anti-aliasing set to 3 at 10 FPS: no stutter

-  changes with Setting |HDR anti-aliasing set to 4 at 9 FPS: stutter (at the end of Log_20220406_1.txt)

-  changes with Setting |HDR anti-aliasing set to 2 at 17 FPS: sometimes stutter (search in Log_20220406_2.txt)

Compared with my post on November 24, 2021 I had to reduce the anti-aliasing slider back to step 1 (FXAA) to get a stable flight without stutter. During the flight (Going around, Missed Approach Procedure and new approach until Final) the FPS is changing between 14 and 25, mainly at 18.

But somewhere I reached again only 10 FPS where the stutter starts again.

So, I reduced the Antialiasing to lowest:

-  changes with Setting |HDR anti-aliasing set to 0 at 10 FPS: stutter (search in Log_20220406_4.txt)

Since it effects in no FPS improvement, the stutter kept staying. Somewhere it disappeared (12-14 FPS), but when the aircraft turned left on leg (D-13. of Approach-EDDN-I28-Z (10 FPS), stutter started again.

This is the printout of Log_20220406_4.txt.

I added the three log files to your convenience as you asked for in in your post on November 24, 2021. May it could help you to find the root cause.

10 FPS is not the best to fly, but it does fly. Flying with stutter is impossible, because the cockpit is stuttering as well and you can’t reliably hit any button.

I’m looking forward to hearing from you.

Gerhard

Log_20220406.rar

[Coop]

Clearly the sim is extremely bottlenecked. The combination of graphic settings + scenery + other plugins is beyond what your computer can handle. Anything below 20fps with the sim will start to breakdown the X-Plane physics model and you'll run at slower than real-speed. If you can upload a screenshot of the full X-Plane graphics settings I can take a look.

[GerdS]

no Problem -

[Coop]

Oh my, that explains a lot! These settings are significantly higher than they should be for your computer's spec. Some settings to change:

• Texture Quality. Try lowering down a notch or two (or three). Right now X-Plane is trying to load around 10 GB of textures into VRAM (much beyond what your graphics card has) so lots of texturing paging would be going on, slowing everything down significantly.
• World objects at high: If your CPU is a bottle neck, lowering this a notch should improve things
• Visual effects. If the GPU is still the bottle neck, lowering this a notch would help

[GerdS]

Surprised? Why? It is the same setting you could have noticed on the pictures above from my former posts –

I don’t have any problems with that most the times, except in this IMC-situation.

But you can trust me: I haven’t sent that to you, if I haven’t checked all the other five sliders before, Visual Effect, Texture Quality, Number of World Objects, Reflection Detail and Anisotropic Filtering.

All on left side didn’t improve the FPS but only the Antialiasing.

Any idea according to the stutter from the Log.txt file?