The glider 3D model was originally developed for x-plane by the Windsocks team in 2007, X-Plane version 8. rhb successfully migrated the model forwards through the X-Plane versions arriving mostly intact at the current x-plane version 11. Wind and spoiler sounds by Timi Hietanen. Subsequent 3D hacks, flight model, instruments, sounds and plugin animations by B21. Testing by the X-Plane Gliders Facebook Group:
Background reading: the ASG29 Pilot Operating Handbook (pdf)
The Schleicher ASG-29 for X-Plane is an 18 meter, flapped, ballast-capable glider with a very high gliding performance across a wide speed range and a state-of-the-art instrument panel.
If you are new to sim soaring, a much better training aircraft is the ASK 21 which is simpler to fly but has similarly capable cross-country instruments so is also suitable for tasks suggested in the X-Plane Gliders Facebook group.
The ASG29_B21 is a comprehensive upgrade of the original Windsocks ASG29 for X-Plane 7, replacing everything except for the 3D model. The instrument panel represents the current most advanced soaring instrumentation for X-Plane and the flight model has received much attention to ensure the glide performance (i.e. the polar) is close to the real aircraft as possible, resulting in the highest performance glider currently available in X-Plane.
There are additional improvements for example in the various sounds, switchable instruments for imperial/metric units, and configurable commands in general intended to make the glider enjoyable to fly. But it is the programming of the existing and new panel gauges where the most significant changes have been made.