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Schempp-Hirth Discus

sch-hir-discusds
Discus CS


The Schempp-Hirth Standard Class Discus was the successor to the Standard Cirrus, and dominated numerous World Championships between 1985 and 1995 (6 world titles in succession). The Standard Class Discus A first flew in 1984 using the fuselage and tail unit of the original Ventus with a new unflapped wing. The wing planform is noteworthy as being the first production sailplane to have the now common distictive shape where the leading edge sweepback increases towards the tip, establishing a worldwide trend in wing planforms.

Approach control is by top surface double panel schempp- hirth airbrakes. There is a 5kg / 11 lb water ballast tank in the fin for trimming purposes when the main wing mounted ballast tanks are used.

The Discus B incorporates the longer fuselage (about 23 cm/ 9 in) and roomier cockpit of the Ventus B.

The sustainer engined Discus bT, which first flew in 1988, has a retractable mast mounted15kW/ 21 bhp Solo engine with a Oehler folding prop.  The T (for Turbo) model incorporates an engine, with no starter, choke and throttle. It is started by wind-milling the multi-blade folding prop. Once started, the engine runs at full power until switched off and then is automatically retracted. Over 150 of the Discus bT were built. The turbo-drive system also equips a successor the Nimbus-4DM.

Whilst the production of the single seat Nimbus-3 had to be discontinued after a fire in one of the production halls, this enabled the production of the Racing Class glider Ventus to be increased, allowing the increase in demand for its motorized variant Ventus-bT to be satisfied.

The self-launching Discus bM has a Rotax engine in the fusealage (in co-operation with Walter Binder) with a retractable mast mounted prop and was manufactured only in small numbers.

The Discus won the first three places in the Standard Class at the 1985 World Championships at Rieti, Italy, 12 out of the first 15 at the 1987 Worlds at Benalla, Austria, and again the first three places at the 1989 Worlds at Wiener Neustadt, Austria. Up to 1995 the Discus won all first places in the world championships.

The Discus CS is built under license in the Czech Republic by Orlican. The winglets (WL) is an option that was developed for further improvement of the climb performance.

After approximately 570 copies weere manufactured in Kirchheim/Teck (including Discus bT and Discus CBM), the Discus A and Discus b production stopped now in favour of the Discus-2. The design Discus CS, identical in constructed with the Discus b, was produced by Schempp Hirth vyroba letadel, at Chocen, CR.

The Discus 2 airfoil is thin (about 14.5 percent), incorporating studies by K.H. Horstmann and Dr. Wuerz (wing) and Luc Boermans (tail). The 5" wheel with a hydraulic brake keeps the fuselage far away from the ground. The tail and cockpit are completely new designs. Empty weight of the prototype is about 240 kg. There is a tail ballast tank.

During stalls in clean configuration (flaps and gear not extended) buffetings on the airspeed indicator begins at about 77 km/h IAS (vortices of the upper fuselage hitting the airspeed probe that was mounted on the vertical tail), followed by a slight vibration at about 73 km/h IAS. The stall ocurred at less than 70 km/h IAS, the airplane vibrating and the airspeed indicator trembling between 65 and 80 km/h.

The Duo-Discus was designed specifically by Klaus Holighaus for two seat high performance flight. With its wingspan of 20m, the two seat fixed profile glider first flew on the 11.03.1993 on the Hahnweide. Despite limited production opportunities, over 150 aircraft were already in service around the world by the end of 1997.

In April 1998, the maiden flight of the first prototype of the Discus 2, registrated D-6111, took place. In 1998 the Discus-2 gained first place in the Hahnweide competition and also National Championships in Germany and England. In late summer 1998, the 250th Discus-CS delievered from Chocen.

1999 brought the maiden flight of the "Duo-Discus-Turbo" and Gunther Stahl became the "Junior World Champion" in the Standard Class with a "Discus-2b".

The Duo Discus was conceived as an advanced trainer with good cross country ability. It has a four piece unflapped wing with a modified Discus wing. The fuselage is derived from that of the two-place Janus. Approach control is by top surface airbrakes.

With the title of European Champion in all three classes, in 2000 two new motor gliders were announced. The Discus-2T, and the Nimbus-4M with an internal lying Solo 2625-02 engine as copied from the Nimbus-4DM.

The World Championships were successful in Mafeking 2001, with a renewed title for the Discus-2 and the Ventus-2ax in the 15m class, a variant sporting a drag reduced tail section and Maughmer winglets. These modifications (which improved the flight characteristics at lower speeds and higher wing loadings) were carried through to the Ventus2-bx, along with a newly designed outer contour and cockpit area shape.

Additionally, the Ventus-2cT won the 18m class at the FAI World Air Games in Lillo/Spain. Mid May 2002 saw the delivery of the first ballistic chute “total recovery system“ fitted to a Ventus-2bxR which was designed by the neighbouring company Glasfaser-Flugzeug-Service GmbH in Grabenstetten and tested in a Discus.

2002 saw the delivery of the 1000th Discus (all variants) as well as the completion of the 1000th Ventus (all variants).

The 18m Discus-2C, first flown on the 16.09.2004, integrates of the “Turbo“ sustainer and shorter outer panels, allowing the Discus-2C to be used in standard class competitions.

Discus
Wing span: 15m / 49.2ft
Wing area: 10.58sq.m / 113.9sq.ft
L/DMax: 43 100 kph / 54 kt / 62 mph
MinSink: 0.59 m/s / 1.94 fps / 1.15 kt
Empty Weight: 228kg / 503lb
Payload: 297kg / 654lb
Gross Weight: 525kg / 1157lb
Wing Load: 49.62kg/sq.m / 10.16lb/sq.ft
Water Ballast: 180kg / 397lb
Aspect ratio: 21.3
Seats: 1

Discus b
Span 15.0 m
Wing area 10.58 sq.m
Wing aspect ratio 21,3
Fuselage length 6.58 m
Unloaded weight approx. 230 kg
Gross weight 525 kg
Wing loading 29.5-49.6 kg/sq.m
Max water ballast 180 lt
Maximum speed 250 km/h
Maneuver speed 200 km/h
Leastst sink approx. 0.59 m/s
Best lift/drag ratio 43

Discus BM
Engine: 35 kW/ 47 bhp Rotax 463
L/DMax: 43 100 kph / 54 kt / 62 mph
MinSink: 0.59 m/s / 1.94 fps / 1.15 kt
Wing span: 15m / 49.2ft
Wing area: 10.58sq.m / 113.9sq.ft
Empty Weight: 228kg / 503lb
Payload: 297kg / 654lb
Gross Weight: 525kg / 1157lb
Wing Load: 49.62kg/sq.m / 10.16lb/sq.ft
Water Ballast: 180kg / 397lb
Aspect ratio: 21.3
Seats: 1

Discus bT
Engine: 15,3 kW / 20,5 bhp Solo 2350
L/DMax: 43 100 kph / 54 kt / 62 mph
MinSink: 0.59 m/s / 1.94 fps / 1.15 kt
Wing span: 15m / 49.2ft
Wing area: 10.58sq.m / 113.9sq.ft
Empty Weight: 228kg / 503lb
Payload: 297kg / 654lb
Gross Weight: 525kg / 1157lb
Wing Load: 49.62kg/sq.m / 10.16lb/sq.ft
Water Ballast: 180kg / 397lb
Aspect ratio: 21.3
Seats: 1

Discus 2
Wing span: 15m / 49.2ft
Empty Weight: 240kg / 525lb
Maximum weight: 525 kg
Seats: 1

Duo Discus
Wing span: 20m / 65.2ft
Wing area: 16.4sq.m / 175.3sq.ft
Empty Weight: 410kg / 904lb
Payload: 290kg / 549lb
Gross Weight: 700kg / 1453lb
Wing Load: 42.7kg/sq.m / 8.74lb/sq.ft
L/DMax: 45
MinSink: 0.58 m/s / 1.9 fps /1.13 kt
Water Ballast: 200kg / 441lb
Aspect ratio: 24.4
Airfoil: HQ-31-A/XX
Seats: 2

Duo Discus T
Engine: Solo 2625-02, 30 hp

 

 


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