The X21 comes in both V-tail and X-tail configuration and various different lay-ups.

The UMS and Double carbon versions come with 6 ballast tubes two in each wing and two in the fuselage enabling the plane to cope with light wind conditions and also when ballasted cope with stronger wind strengths.

It has large flaps which when properly setup give amazing breaking power when coupled with the ailerons and give the plane a roll rate that many smaller span gliders would like to emulate.

The MH32 based wing section still performs superbly and responds very well to camber adjusment both for extra camber for duration and also to reflex for a bit of speed.

I have flown the X21 for nearly 3 years now starting with the UMS V-Tail I now have a double carbon X -Tail.

The double carbon X Tail is fitted out with digi servos with very little slop in the linkages, which means it feels much more responsive , but the carbon surfaces probably help as well.