Which, by the way, is not final yet, so make sure you understand you are still using an unfinished version of X-Plane 12.
Nonetheless, some developers have been working on updating their helicopters to the new version, but X-Trident has been calmly waiting.
They did release a patch for their 412, which brings:
- improved compatibility with xp12 (engine start, skids elevation on ground, engine power)
- more tail rotor authority
- includes latest xp11 patches for proportional rotor brake and emergency floating device
- experimental support for rain effect
You can see a forum post at the .org about this and you can also download the patch here.
X-Trident says there is still a lot to do to make the 412 fully compatible with X-Plane 12, so we should perhaps expect a bigger, more complete version or patch in the future.
