ROTATION ACCELERATION BODY not always settable (even if airborne)

Questions & Community Discussions Aircraft
1

During experiments with XML scripts I’ve noticed that ROTATION ACCELERATION
are not settable properly during specific conditions (even if while aircraft
airborne), usually because of the low airspeed, tested on Cessna 152. I have
made a simple script that hold aircraft in the air with 0m/s velocity and nose
pitch down:

                30
                
                    10 (>A:ROTATION ACCELERATION BODY Z, radians per second)
                    1000 (>A:PLANE ALTITUDE, meters)
                    1.3 (>A:PLANE PITCH DEGREES, seconds)
                    0 (>A:PLANE BANK DEGREES, seconds)
                    0 (>A:VELOCITY BODY Z, knots)

Most important is the line

10 (>A:ROTATION ACCELERATION BODY Z, radians per second)

which should make aircraft roll to the left all the time. However, most of the
time it does not work - plane continue to dive without rotation. Another clue

  • if you open SimVarWatcher and load this variable, you can see it actually
    equal to 10 most of the time, so XML script set it properly but it ignored by
    physics engine. And last - if you will try to set this value to 10 with
    SimVarsWatcher manually - airplane will start to roll as expected. Is there
    any way to avoid such unstable behaviour of this variable and make it settable
    all the time? It feels like there is not only “in the air” limitation but some
    other, that appear unexpectedly and only for XML scripts.
2

Your frequency is too low… to override these variables you have to do them on
every sim update frame… they are writable but the base simulation will be
fighting with you in putting another value. The correct way to do this is to
increase your update frequency, be aware when you are on drone camera and move
away from the aircraft, the update frequency will be throttle down by MSFS
causing the variable to stop updating as fast as you need. In my personal
experience, XML will not give you what you need for one reason or another and
in order to override these types of variables that are crucial for MSFS (such
as body velocity, etc), You will need to eventually implement custom flight
models via other solutions such as SimConnect or WASM in order to keep up the
speed of update required. In addition, I believe the right unit to use with
acceleration variable is meters per second, not radians per second or anything
else… Best, R.