Cirrus Autopilot

[Doom]

Can someone explain me how does this thing work?

What I want to do is to set up target height, make the plane reach it and stay there. Then adjust height up/down when needed.

I can make it work in Cessna Skyhawk just fine ,there I enable "Alt" mode and Altitue knob allows me to change the flying height in increments of 200 feet. Alternatively I can use "VS" (vertical speed) button and specify how fast I want to fly up/down.

In Cirrus I can make the plane follow heading more or less (Press AP, then HDG, then mess with the Heading), but anything related to altitude is very erratic, the plane is constantly pitching up down, and does not appear to hold the altitude correctly. Basically, setting ALT (on auto pilot panel, above throttle) button sets current height as "autopilot" height, except the plane doesn't exactly stay there and goes up/down by noticeable amount. The manual mentions that FCN should make you go to a different height, and I can move height selector up/down but it doesn't seem to follow it.

What am I missing?

[Doom]

If that matters, I'm playing in VR on Oculus Quest. I have a lingering suspicion that I might be messing with a wrong dial (Alt Sel vs Altitude), but I'm not 100% sure yet.

[Doom]

So, I tinkered with it a bit more, and it looks like Cirrus autopilot simply does not work the same way Cessna autopilot does, meaning you can't make the plane maintain height and then slightly adjust desired height with a dial/knob (like in cessna).

Instead you select desired height first and then go into "VS" (vertical speed mode), select desired climb/descend speed and then the autopilot will level off at the height you set when it reaches it. This is a bit more annoying than cessna autopilot.

I'm not sure if there's another mode of operation, although the manual implies that FLC mode should work the way I want....

Originally posted by SRΑKA PTAKA:

Hi buddy

I do not fly Cirrus and I will not help you precisely, but I can give you some ideas to check for yourself. Namely; a few things come to mind

1. Check how the autopilot and the plane behave in the virtual cockpit mode in the mode without armed (turned on) VR

2. Check the airspeed while climbing to the desired target altitude

3. Check if the trimmer is not blocked in any way or if its operation is disturbed by the VR system, keyboard, mouse or other peripherals

greetings

1. Virtual Cockpit is the same one VR cockpit as far as I'm aware, so if you can click something with mouse, you can click it with a VR control. I haven't noticed any missing or unresponsive controls there.
2. The plane isn't stalling, Cirrus has green green indicator for acceptable airspeed and start blaring alarms at you if you raise/lower nose of the aircraft too fast. Actually I'm not sure why it was going up/down (+- 10 degrees) so much yesterday, maybe the weather had something to do with it.
3. I don't have any controls assigned to trim wheel, basically I only have an old thrustmaster joystick and VR touch controls, and that's it. Trimming is controlled by the autopilot while it is trying to maintain altitude

[Doom]

I found this.

https://questions.x-plane.com/22005/cirrus-vision-wont-hold-altitude?show=22053#a22053

Looks like the autopilot will go bonkers with speed over 240 (it will try to "brake" by raising nose up, which will screw up altitude seeking), due to some changes they did to 11.30. This can be fixed by either staying under 240 knots, or tweaking config files for the plane.

As far as I can tell they changed the VNE (Velocity Never Exceed) from 350Kts to 250Kts in either 11.30 RC1 or RC2. This means if you exceed about 240kts on autopilot, it will nose up to bleed off speed gaining altitude in the process. If this is your problem, you can fix it. Navigate to the Aircraft > Laminar Research > Cirrus SF-50 folder and open the file CirrusSF50.acf with a text editor. Search for an entry "P acf/_Vne_kts". If this is set to 250, change it to 350 and save. Hopefully this will fix your problem.