The Schempp-Hirth Discus is a

Standard Class Competition classes in gliding, as in other sports, mainly exist to ensure fairness in competition. However the classes have not been targeted at fostering technological development as in other sports. Instead classes have arisen because of: * t ...

glider Glider may refer to: Aircraft and transport Aircraft * Glider (aircraft), heavier-than-air aircraft primarily intended for unpowered flight ** Glider (sailplane), a rigid-winged glider aircraft with an undercarriage, used in the sport of gliding ...

Schempp-Hirth Schempp-Hirth Flugzeugbau GmbH is a glider manufacturer based in Kirchheim unter Teck, Germany. History Martin Schempp founded his own company in Göppingen in 1935, with the assistance of Wolf Hirth. The company was initially called "Sportflu ...

. It was produced in

Germany Germany, officially the Federal Republic of Germany (FRG),, is a country in Central Europe. It is the most populous member state of the European Union. Germany lies between the Baltic and North Sea to the north and the Alps to the sou ...

between 1984 and 1995 but has continued in production in the

Czech Republic The Czech Republic, or simply Czechia, is a landlocked country in Central Europe. Historically known as Bohemia, it is bordered by Austria to the south, Germany to the west, Poland to the northeast, and Slovakia to the southeast. Th ...

. It replaced the Standard Cirrus. It was designed by Klaus Holighaus.

Design and development

The Discus was the first production sailplane to have a distinctive swept-back leading edge. This is now common in contemporary sailplanes. Studies had long shown that the ideal wing for minimizing

induced drag In aerodynamics, lift-induced drag, induced drag, vortex drag, or sometimes drag due to lift, is an aerodynamic drag force that occurs whenever a moving object redirects the airflow coming at it. This drag force occurs in airplanes due to wings or ...

should be an elliptic planform. To keep production costs down, a triple-trapezoidal approximation of this shape was adopted for the Discus. The wing section was also new.

Winglets Wingtip devices are intended to improve the efficiency of fixed-wing aircraft by reducing drag. Although there are several types of wing tip devices which function in different manners, their intended effect is always to reduce an aircraft's ...

were only available towards the end of the production run, though many have been retro-fitted. The fuselage and tail were adapted from the Schempp-Hirth Ventus. A version with a narrow fuselage is called the Discus 'a' and the wider fuselage version is called the 'b'. The fuselage is made of

glass-reinforced plastic Fiberglass (American English) or fibreglass (Commonwealth English) is a common type of fiber-reinforced plastic using glass fiber. The fibers may be randomly arranged, flattened into a sheet called a chopped strand mat, or woven into glass cloth ...

around a steel tube frame. The wings and tail surfaces are also fiberglass with the exception of the main wing spar, which is made of

carbon fiber Carbon fiber-reinforced polymers (American English), carbon-fibre-reinforced polymers (Commonwealth English), carbon-fiber-reinforced plastics, carbon-fiber reinforced-thermoplastic (CFRP, CRP, CFRTP), also known as carbon fiber, carbon compo ...

. There is a water ballast tank in the fin for trimming purposes when the main wing mounted ballast tanks are in use (184 L combined) for a maximum wing-loading of

Competition use

The Discus dominated standard class sailplane racing throughout the 1980s, winning six

World Gliding Championships The World Gliding Championships (WGC) is a gliding competition held every two years or so by the FAI Gliding Commission. The dates are not always exactly two years apart, often because the contests are sometimes held in the summer in the Southern ...

in a row from 1985 to 1995.

Performance

The best measured

glide ratio In aerodynamics, the lift-to-drag ratio (or L/D ratio) is the lift generated by an aerodynamic body such as an aerofoil or aircraft, divided by the aerodynamic drag caused by moving through air. It describes the aerodynamic efficiency under gi ...

is 42.5:1. Though it is considered a high performance sailplane, its handling is well within the capabilities of inexperienced pilots. With no bad manners, powerful airbrakes and a low landing speed, the Discus is popular with clubs. Discuses are easy gliders to assemble, having light wings, automatic control hookups and a single pin securing the wings.

Production

Over 850 Discuses had been built by 2004 and it remains in production today despite the introduction of its successor, the Schempp-Hirth Discus-2. About 12 per year are built under license by Schempp-Hirth Vyroba in the

as the Discus CS. Some models are fitted with small sustaining engines (turbos) and are designated Discus T.

Variants

;Discus a: Short fuselage and narrow cockpit optimized for smaller pilots, utilising the fuselage and tail of the Ventus a. ;Discus b:Standard production model utilizing the fuselage and tail of the Ventus b. ;Discus bT:Discus b with a retractable sustainer motor ;Discus bM:Motor-glider with retractable engine ;Discus CS:Continued production in the

;Discus K: Aerobatic version first flown on 18 November 1987. This was, due to disappointing performance in aerobatic, later converted back to a standard version.https://www.segelfliegen-magazin.de/wp-content/uploads/2013/05/discus.pdf

Specifications (Discus b)

References

External links

Schempp-Hirth WebsiteA Flight Test Evaluation of the Discus Sailplane, by R.H. Johnson, published in Soaring Magazine, February 1986British Gliding Association, Discus datasheetSpecifications of Schempp-Hirth Discus
{{Schempp-Hirth 1980s German sailplanes Discus T-tail aircraft Aircraft first flown in 1984