It is often used for advanced training. The Duo Discus replaced the Janus as Schempp Hirth's high performance two seater trainer. Although it shares its name with the highly successful Standard Class Discus, any resemblance is only superficial. It first flew in 1993 and is still in production at the factory in Orlican in the Czech Republic. It has a 20 meter four piece wing that is slightly swept forward so that the rear pilot is close to the center of gravity. Its best glide ratio was measured as 45:1