I noticed one thing: The ASK-21 in your video has "braces" (Dunno
what they
are properly called) inside the canopy that those of my future club
don't
seem to have:

http://www.akaflieg-bonn.de/flugbetr/flugzeug.htm

Or

http://www.alexander-schleicher.de/e...ask21_main.htm

Is that a question of age or some special modification?

Hi,

These bars are a protection against the barbed wires (when
outlanding). There have been deadly accidents with gliders that hadn't
got these and outlanded it a too short field (not in our glidingclub I
believe).

So that's why all of our club's gliders have one installed.

Regards,
Peter.

p.s. in Dutch we call them "prikkeldraadstangen" (don't know how to
translate it, but something like "barbed wire bars").