I just want to underscribe the statement:
Don't Ever Do the Airbrake Dive in the DuoDiscus Mk 1.
It won't have the desired effect, while actually bringing the sailplane in ground effect at very high speeds. Unless you have 3 km or more of runway in front of you.
The 2nd generation of the Duo (with landing flaps) allows this technique. The Arcus has powerful drag devices. Totally different beasts when managing the energy for landing.

Been there, done that, had vertebrae concussion and a nerve compression.

Aldo Cernezzi
www.voloavela.it