I've done a couple flights recently where I've put the plane into AP and turned on the sim rate. Within seconds the plane is pitching up and down as the AP tries to keep the plane in level flight. Of course, this isn't happening normally. It gets so bad that eventually the AP cuts off. 

Normal? If so only restricted to this or a few planes? Because I can't image why have the ability to increase the sim rate when it causes this to happen....so is it a bug and needs reporting?

I also notice in several videos of fMSFS2020 fight operations, the aircraft are bouncing around in what seems to otherwise clear air.  My experience in many hours of actual flight operations is that the air can be bumpy but more often it is smooth and the aircraft maintains a steady flight profile.  Flying below scattered clouds, bumpy; flying above scattered clouds, smooth.

Jim Driskell

13 minutes ago, bahnzo said:

I've done a couple flights recently where I've put the plane into AP and turned on the sim rate. Within seconds the plane is pitching up and down as the AP tries to keep the plane in level flight. Of course, this isn't happening normally. It gets so bad that eventually the AP cuts off. 

Normal? If so only restricted to this or a few planes? Because I can't image why have the ability to increase the sim rate when it causes this to happen....so is it a bug and needs reporting?

Had the same problem in the Longitude.  We should be able to accel time without this especially considering jumping to a waypoint kills your autopilot settings leaving you scrabbling to get things back together as you loose altitude.  

3 minutes ago, jmdriskell said:

I also notice in several videos of fMSFS2020 fight operations, the aircraft are bouncing around in what seems to otherwise clear air.  My experience in many hours of actual flight operations is that the air can be bumpy but more often it is smooth and the aircraft maintains a steady flight profile.  Flying below scattered clouds, bumpy; flying above scattered clouds, smooth.

Jim Driskell

This is what I'm wondering, because when flying at the standard rate, it's fine, but I'm sure the AP is adjusting trim to keep the plane steady. Increasing the rate seems to be causing the sim to over/under compensate and causing the plane to porpoise. Like I said it gets so bad it cuts off the AP. 

1 minute ago, Dillon said:

Had the same problem in the Longitude.  We should be able to accel time without this especially considering jumping to a waypoint kills your autopilot settings leaving you scrabbling to get things back together as you loose altitude.  

Alright, so I'm inclined to think this is a bug and should be reported.

Seems to me that increasing the simulation rate should dampen or smooth out the autopilot's sensitivity and responses thru an averaging algorithm of some sort.  

Jim Driskell

It’s a general problem with a lot of sims. Go 8x in P3D and the plane will go nuts sometimes. I think the simulation of the AP can’t keep up with the rapidly changing conditions.

Maybe they could one day make it so wind/weather no longer affect the plane when accelerating time. 

I think the oscillations are still there whatever speed you run the sim, but if you double the sim rate they are more obvious. At higher sim rates the oscillations effectively lower the perceived inertia (not the actual inertia) of an aircraft and the movement for example in roll and yaw is more pronounced. I am working on a flight model trick to dampen out the oscillations almost completely, but it is very time consuming and does not damp the effect when doubling the sim rate. The oscillations are not actually written into any flight model, but are global effects, a bit like weather effects but permanently present.

The more I delve into this the more I am convinced that it is a developer decision to bake in the effect in pursuit of the "no more on rails" policy. The problem with that is  1) It isn't very subtle and 2) you can clearly see it is an artificial effect.

Edited September 1, 20205 yr by robert young