# Schempp-Hirth Janus

The Schempp-Hirth Janus is a high performance two-seat glider that was built by Schempp-Hirth GmbH. It was the first high-performance two-seater.

## Design and development

The design was by Dipl-Ing Klaus Holighaus and the prototype first flew in May 1974. The production examples incorporated several improvements in January 1975. The Janus has a glass-fibre monocoque fuselage similar to that of the Nimbus-2 but the cockpit section is lengthened to accommodate the two pilots in tandem with dual controls under a right-hand side-hinged one-piece canopy. Landing gear consists of either a non-retractable main wheel (Janus A, B & C) or a retractable main wheel (later models of Janus C and all Ce's) with a drum or disc brake, and a nose-wheel. The two-piece wings have 2° forward sweep on the leading edge, and have camber-changing flaps which are operated between +12° and -7°. The Janus has upper-surface airbrakes, and although uncommon the Janus C could also be fitted with a tail parachute.
The Janus was superseded by the unflapped Duo Discus which first flew in 1993; and the flapped Arcus which first flew in 2009.

### Production

100 Januses were built by early 1980 plus three motorised Janus CMs. It is particularly suitable for instruction in cross-country flying in gliders with wing flaps.

## Variants
### Janus B

    The Janus B was produced from March 1978. It has a fixed-incidence tailplane instead of the all-moving type previously fitted.

### Janus C

    The Janus C has carbon-fibre wings of 20 m span and a carbon-fibre tailplane.

### Janus Ce

    The Janus Ce was certified in 1991 and incorporated modifications to the cockpit and fin.

### Janus CM

    motorised version with Rotax 535C engine

### Janus CT

    motorised version with Solo 2350 engine

### Janus M

    a motorised version with a Rotax engine mounted on a pylon aft of the cockpit and retracting into the fuselage. The prototype first flew in 1978.

### SCAP–Lanaverre SL-2

    The French developed the Janus as the SCAP–Lanaverre SL-2. (SCAP - Société de Commercialisation Aéronautique du Plessis SàRL) with Lanaverre Industries, It first flew in 1977. The main differences from the Janus A are the provision for water ballast in the wings, a fixed tailplane with elevators, and a more comfortable cockpit.

## Specifications (Janus C)

Data from Jane's All the World's Aircraft 1988-89
General characteristics
* Crew: 2
* Capacity: 2
* Length: 8.62 m (28 ft 3 in)
* Wingspan: 20 m (65 ft 7 in)
* Height: 1.45 m (4 ft 9 in)
* Wing area: 17.4 m$^2$ (187 sq ft)
* Aspect ratio: 23
* Airfoil: root:Wortmann FX-67-K-170; tip:Wortmann FX-67-K-15
* Empty weight: 355 kg (783 lb)
* Max takeoff weight: 700 kg (1,543 lb)
* Water ballast: 200–240 L (53–63 US gal; 44–53 imp gal)
Performance
* Stall speed: 70 km/h (43 mph, 38 kn)
* Never exceed speed: 250 km/h (160 mph, 130 kn) ::::180 km/h (97 kn; 110 mph) on aero-tow
             150 km/h (81 kn; 93 mph) on winch launch
* g limits: +5.3 -2.65
* Maximum glide ratio: 43.5 at 110 km/h (59 kn; 68 mph) at 36.5 kg/m$^2$ (7.5 lb/sq ft) wing loading
* Rate of sink: 0.6 m/s (120 ft/min) at 90 km/h (49 kn; 56 mph) at 36.5 kg/m$^2$ (7.5 lb/sq ft) wing loading
* Wing loading: 40 kg/m$^2$ (8.2 lb/sq ft) max