Request : V/S change smoothing

pds

Hi

Request to please allow V/S changes to be smoother and not as abrupt as it currently is please. At the moment, any change in V/S (ft/m) causes the plane to jerk up and down suddenly, and is not as smooth as the real plane from what I've seen on the real plane. Not sure if this is a sim limitation, but i have seen other planes in the sim do this smoother, so it should be possible I hope.

Thanks

sg_aviation

@pds @Black-Square I can confirm the same. When engaging VS, the flight director points approx. 7,5° up before returning to level flight. Then you can adjust the vertical speed, which is followed quite rapidly.

pds

I've not seen anyone deal with V/S like this guy. I want to try and adopt this approach. The KAS 297B instrument does my head in. I just cant get to grips with how it operates ( the V/S portion at least ), and it is way to abrupt as I mentioned.

https://youtu.be/C6pI1wPc6U4?t=3472

krause

Yes, this is one of the most annoying things in flight sims that happens a lot with addons. Other than that, I am glad the dev is very open to feedback :)

Black Square

While IAS mode is my personal recommended method for climbs and descents, that video is not correct that IAS mode is the only method of climbing and descending. The KAS 297B has a VS button for a reason. Just dial in your desired altitude, press the VS button, pull the knob out, and then select your desired vertical speed.

I tried a few things to adjust to fix the abrupt pitch changes when it first came up, but to no avail. I'll compare some files later and see if I can spot the difference. Hopefully it doesn't come down to the PID control loop, because that can be a little dangerous to edit, especially in higher performance aircraft, where the autopilot might induce pitch oscillations.

pds

I think i can see what is happening Nick, perhaps you have seen this too....

Please have a look at what SteveO does when he descends in the video below. He has already preselected a lower altitude of 12000, and is about to use the KAS 297B to arm and engage the V/S to this altitude from what i assume is a higher altitude where he is at that moment. Notice how smoothly the descent starts once he performs these steps in order :

ARM lower altitude by pushing ARM button
Pull the inside knob and dial in a 1500ft/m V/S ( down ) - note on the V/S indicator that the plane does not move an inch while he does this
Pushes Engage to allow the plane to START the descent - note the plane does NOT start down before he hits ENG

https://youtu.be/87MlpUJHVsY?t=1318

I tried to replicate these actions EXACTLY in order with your plane a few mins ago, and this is the behavior I see,

As soon as you hit ARM, the plane jolts slightly even if the current V/S is 0fpm, and if it is at any non-level V/S it will dive or climb based on what it was when you hit ARM, and actually continue to descend ( or climb, which it should not do ? You are just arming the new altitude...)
But lets assume V/S was 0 ft/m at the point you pull the inside dial and dial in a V/S. Then, as soon as you start to dial in a V/S the plane immediate starts to descend ( or climb if you were ascending ), which it should not do, it should wait for you to hit ENG as seen in SteveO's video, and then slowly drop ( or raise ) the nose.
Therefore, ENG doesn't seem to do anything, as the plane now already started it's V/S descent ( or ascent )

Hope that makes sense ?

Thanks

Black Square

Thank you for the walkthrough. Yes, this is a well known limitation of MSFS. The native autopilot does not support VS arming, so any adjustment to the commanded VS will immediately initiate a climb/descent. As I've learned more about what can be done to circumvent the simulator's numerous limitations (it seems over half my time developing aircraft is just overcoming this limitations, and fighting the simulator all the way), I have an idea of how I could implement the correct behavior. What complicates matters is that it still has to play nicely with 3rd party GPS products that implement their own autopilots. This is not something I'm leaping to do right now, but I will revisit it after I release the Dukes, which do not use the KAS 297B.

I should add that this limitation is not the cause of the abrupt pitch changes, though. That's entirely on the autopilot's inner control loop, as opposed to mode control, which is the outer control loop, as controls engineers would say.

FidoCZ

Hello, just stumbled upon this thread, and registered just to get a reply in :D
First, thank you for the great plane, it's really enjoyable, honestly, biggest downside for me is the prop buzz from the default MSFS TBM 930. It would be great if any future update could change the sound, even if it wouldn't be exactly TBM 850 sound.

Anyway, back to topic, I believe KAS 297B is used in the PC-12/47, and while the SWS model has it's own set of problems in my opinion, I believe the altitude and VS selector is working correctly, including arming the altitude and engaging the VS mode. Their PC-12 also supports WT GNS530, PMS 750 and TDS GTNxi.

I'm not sure if it would be acceptable for you (or them), but maybe they could point you in the right direction of how they implemented it.

Anyway, thanks again for the great mod, looking forward for more to come.

Best regards.