Just transitioned to XP11 a couple of weeks ago, from Microsoft FS since its very 1st edition by Bruce Artwick’s  in 1977.  Without any add-ones (yet, except for X Camera, which is another story), I find XP11 most definitely better than default FSX . . a 32 bit sim is no comparison to a 64 bit sim.  

But I’ll get to the point of this post. Regarding the default XP11 B-737 and 747, I noticed that on a cruise with or without autopilot on, the plane would suddenly but momentarily, pitch up on it’s own as if it were trimming itself up from level flight. If autopilot is on with Alt on hold, the plane would then “trim itself” to the set altitude after a few minutes.  This uncommanded pitch upward happens intermittently.  It does this with the weather set to clear and calm (unless XP has random weather/wind gust aloft that I’m not aware of).  Has anyone else noticed this? Any update fix for these default planes?

Thanks for any info you can share.

Don't know or not sure about the airliners update but you could search for Zibo Mod for the default 737-800 which is perhaps the best freeware airliner yet (for any simulation in my opinion), is an almost complete mod that competes without a problem with many payware planes. Look at the org.

Good luck,

The default planes are not all that good but yes as mentioned above try the default 737 with the ZIBO mod.

I did read about the Zibo Mod for the 737-800.  Will definitely download it and not waste time figuring out the quirks in these default planes!  It makes you wonder .  . if someone can improve upon a default plane, why don’t these companies that create these flight sim programs, produce quality default planes to begin with?  After all, the main feature/emphasis in a home flight sim program is in flying “flyable” planes as close to reality as possible that can be achieved with a home PC.

Thanks! You just convinced me to go for the Zibo Mod!