Earlier, wrote:

Denis a Nimbus 4 does not have airbrakes. It has spoilers. These are
two different animals alltogether

I'm not one to be a sticker about such things, but I generally observe
this system: If the boards hinge out of the wing surface like on a
Schweizer, I call them spoilers. If they slide out of slots in the wing
like on most European ships, I call them airbrakes.

Anyhow, the factory calls them airbrakes, specifically "Schempp-Hirth
type airbrakes." From the Schempp-Hirth Web site:

The wing (six pices for easier rigging)
has full span camber-changing flaps and
double-panel Schempp-Hirth type airbrakes
on the upper surface of the inboard panels.

The standard text on sailplane design, _Fundamentals of Sailplane
Design_ by Fred Thomas (translated by Judah Milgram), generally applies
the term "dive brake" to any flat nasty that comes out of a glider
wing. It does mention in passing that hinged panels are often referred
to as "spoilers," but that is the only use of the term.

Thanks, and best regards to all

Bob K.
http://www.hpaircraft.com