Sorry mate, my sodding connection keeps dropping, not connected with my last challenge, nor Wasserkuppe
If it helps and I'm sure it won't, that suggestion of Breeze means absolutely nothing to me!
Have you got the country yet? only fifteen larger in Europe!
Not that many aircraft manufacturers there, but the engineers from one of them helped with the building of this and other gliders on an amateur basis, saying The work was done in the evenings - after school, after work.
The design engineer Hermann Winter was there in 1925 (before his career at Fieseler) the country is now obvious!
They named their gliders after military "National Heroes",
Vekilski, Drang, and Toprakchiev, the first of these is the challenge machine.
These Gliders don't appear in the wiki list of aircraft produced by this fairly well known company, but they are
shown on a Russian website (just love that 225, an elegant giant!) and others, they're listed under the company name and the UK's "striking year"!
Well, there should be enough there to goggle your way to the challenge, but this won't be helped by the fact that the underlying text is not in english, as witnessed by the translation of the challenge's page, which reads as total gibberish!!