Schempp-Hirth Duo Discus

{{Short description|German two-seat glider, 1993}} {{More footnotes|date=December 2012}}  {{Infobox aircraft | name=Duo Discus | image=Schempp-Hirth DuoDiscus.jpg | caption=Duo Discus T flying over the ridges of Pennsylvania, US | type=[[FAI Two Seater Class|Two Seater-class]] sailplane | national_origin=Germany | manufacturer=[[Schempp-Hirth]] | designer= | first_flight=1993 | introduction= | retired= | status= | primary_user= | number_built=750 as of Sept 2023 <ref>{{cite news | url=https://www.schempp-hirth.com/en/company/latest-updates/latest-updates-details/auslieferung-des-750-duo-discus | title=Delivery of the 750th Duo Discus }}</ref> | developed_from= | variants= }}

The '''Schempp-Hirth Duo Discus''' is a high-performance two-seat [[Glider (sailplane)|glider]] primarily designed for fast [[cross-country flying]], including [[gliding|gliding competitions]]. Often, it is used for advanced training.

==Design and development== The Duo Discus replaced the [[Schempp-Hirth Janus|Janus]] as [[Schempp-Hirth|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 the wing root can be slightly aft to allow the rear pilot an improved view. Although it shares its name with the highly successful Standard Class [[Schempp-Hirth Discus|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]]. Its best [[glide ratio]] was measured as 44:1. An optional 'turbo' retractable [[two-stroke engine]] can be specified for extended gliding sessions. As of August 2007, over 500 Duo Discuses have been built. In the U.S. Air Force, it is known as the '''TG-15A'''. The chief rival of the Duo Discus is now the [[DG Flugzeugbau DG-1000|DG Flugzeugbau DG-1001]].

===Duo Discus X=== A revised model, the Duo Discus X, was announced in 2005. This has landing flaps incorporated into the movement of the airbrake lever to improve its approach control, giving steeper and slower approaches. It also has [[winglet]]s to improve thermal flying, and a sprung and lower retractable undercarriage.

===Duo Discus XL=== The Duo Discus XL is the latest version. It shares the same fuselage as the [[Schempp-Hirth Arcus]] and the [[Schempp-Hirth Nimbus-4|Schempp-Hirth Nimbus 4DL]]. 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 18 mm higher. The XL is certified for simple aerobatics, including spinning. It can also be flown entirely from the back seat.

===Duo Discus XLT=== The Duo Discus XLT is a motorized version of the Duo Discus XL.

==Specifications (XL)== {{Aircraft specs |prime units? = met |crew=Two |capacity=200 kg (440 lb) water ballast |length m=8.73 |length ft=28 |length in=3 |span m=20.00 |span ft=65 |span in=7 |height m=1.60 |height ft=5 |height in=3 |wing area sqm=16.4 |wing area sqft=176 |aspect ratio=24.4 | airfoil =DFVLR HX 83 |empty weight kg=410 |empty weight lb=900 |gross weight kg=700 |gross weight lb=1,540 |max speed kmh=263 |max speed mph=164 |glide ratio=46-47 |sink rate ms=0.58 |sink rate ftmin=114 }}

==See also== {{aircontent  |see also= |related= |similar aircraft= *[[Glaser-Dirks DG-500|Glaser-Dirks DG-505]] *[[DG Flugzeugbau DG-1000]] |lists= *[[List of gliders]] }}

==References== {{Reflist}} {{Commons category}} * [http://www.schempp-hirth.com/index.php?id=33&L=1 Specifications of Schempp-Hirth Duo Discus]

[[Category:1990s German sailplanes]] [[Category:Schempp-Hirth aircraft|Duo Discus]] [[Category:Motor gliders]] [[Category:T-tail aircraft]] [[Category:Aircraft first flown in 1993]]