The Schempp-Hirth Duo Discus replaced the Schempp-Hirth Janus as Schempp Hirth's high-performance two-seater trainer. It has a four-piece wing with a span of 20 metres. As with most tandem two-seat gliders its wing is slightly swept forward so that the wing root can be slightly aft to allow the rear pilot an improved view. Its best glide ratio was measured as 44:1.
The Duo Discus XL is the latest version. The cockpit is now 10 cm longer to improve seat comfort, security, space and ergonomics. The airbrake system has been moved 4 cm towards the leading edge and now extends 18mm higher. The XL is certified for simple aerobatics, including spinning. It can also be flown entirely from the back seat.
An optional 'turbo' retractable two-stroke engine can be specified for extended gliding sessions (Duo Discus XLT variant).