stec-55x problem

[diamonddriller]

I have just upgraded to a Mac Studio, and run XP12 natively on the M processor (i.e. not Rosetta).

I can't remember whether the stec-55x is supposed to have altitude preselect working on the Entegras - because my last Intel iMac couldn't run these planes without flashing screens, so I hardly used them, and stuck with the G1000s.

Anyway, today, I found that altitude preselect (what I fed in on the Entegra PFD) was totally ignored by the autopilot.  In fact, even the VS speeds were not kept to very accurately.  Is this possibly a problem with the M processor?  I had, earlier, tried the same plane in X-Plane 11 running in Rosetta, and the autopilot verged on being almost unusable for altitude control, and I gave up.  

I, so far, have had very limited experience in X-Plane using Mac Silicon, so I don't know what works, and what doesn't!  I get super fps, which is a big plus.

[Cameron]

The aircraft function is the same regardless of platform. Altitude pre-select should be followed so long as a vertical mode is active. This will ARM the pre-selected altitude.

For VS, are you saying it will not obey a commanded higher pitch, or are you trying to use an IAS mode?

[diamonddriller]

Hmmm.  I'll try again later, but the preselect was not working for me.  I know how to use this, but maybe I got something wrong yesterday...  We'll see.

No, IAS was not being used.  It sort of followed the commanded VS, but it was not that accurate, and when well off the selected altitude, it was nowhere near right.

Flies very nicely, but taxiing can be difficult.

-------------------

I just tried it again.  Started with engine running (saves time!), and it worked properly!   Yes, it wanders about a bit from the assigned altitude, but that is expected and realistic, as the air is not static!  It does correct itself.  So, as to quite what was going on yesterday, I have no explanation. 

If it happens again, I'll send you a log file.  Thanks for your interest :-)

 

Edited May 13 by diamonddriller
Additional info.

[Coop]

The STEC AP being used is the internal XP STEC. It is an incredibly dumb autopilot (as it is in the real world). It definitely is night and day in behaviors compared to modern APs (DFC90 with the Entegra, or anything Garmin, etc.)

[diamonddriller]

13 hours ago, Coop said:

The STEC AP being used is the internal XP STEC. It is an incredibly dumb autopilot (as it is in the real world). It definitely is night and day in behaviors compared to modern APs (DFC90 with the Entegra, or anything Garmin, etc.)

   Thanks Coop!