Schempp-Hirth HS.6 Janus
Design work on the Janus was begun by Dipl-lng Klaus Holighaus in 1969, was continued from early 1972 onwards and the prototype first flew in May 1974. Production began with the second aircraft, incorporating several improvements, in January 1975.
The Janus seats two in tandem with the rear seat occupant positioned near the center of gravity. The original Janus and Janus B (first built in 1978) models had an 18.2 m. wingspan, fixed landing gear and a gross weight of 621 kg / 1,370 lb. The Janus B became available to customers in March 1978, seating for two and provision is made for up to 200 lb of water ballast in the wings but use is not recommended unless lift is expected to exceed 3.3 ft/sec. The flaps adjust from -7 o to +10 o. The glider is fitted with airbrake and tail parachute. The Janus B this having a fixed incidence tailplane instead of the all-moving type previously fitted.
The Janus has a glassfibre monocoque fuselage with bonded in foam bulkheads, and this is similar to the Nimbus
2's but the cockpit section is lengthened to accommodate the two pilots in tandem with dual controls under a hinged one-piece canopy. Landing gear consists of a non-retractable monowheel with a drum brake, and a nosewheel; there is also a bumper under the rear fuselage. The two-piece cantilever mid wings have 2° forward sweep on the leading edge, and are of glassfibre/foam sandwich construction, with glassfibre monocoque ailerons, flaps and Schempp-Hirth air brakes in the wing upper surfaces; the camber-changing flaps are operated between +12° and -7°. The tailplane is also of glassfibre/foam sandwich construction.
The Janus C first built in 1979 has a 20-meter span with carbon wings and a carbonfibre tailplane, seating for two, and competition-type performance. The Janus CM, with a 20-meter span, is a two-place motorglider with carbon wings and fully retractable engine. The Janus C incorporated carbon fiber components, retractable gear, and a gross weight of 700 kg./ 1,543 lb. Camber-changing flaps (+12 to -7 degree), top surface-only airbrakes and a tail drag chute provide options for approach control. In all versions a small fixed wheel between the main gear ant the nose allows strong braking without scraping the nose.
The Janus M prototype, D-KIBO, first flew in 1978 and is a motorised version with a 55hp Hirth 0-28 engine mounted on a pylon aft of the cockpit end retracting into the fuselage. Motorised versions are the Janus CM self-launcher with retractable mast mounted Rotax two cycle engine, and the sustainer Janus CT with a 15 kW/ 21 bhp Oehler Solo 2350 turbo engine.
The self-starting version, the JANUS cm, flew for the first time 1978 and to it in several dozen copies to all world was supplied, at first with an Hirth engine, later then with a Rotax engine type 535. One hundred examples of all versions of the Janus had been delivered by early 1980 plus three motorised Janus CMs.
The Royal Air Force acquired 2 Janus C’s for its air cadet program.
No. of aircraft built to 10/15/81 120 (all versions).
The Janus has set several speed and distance records for two-seaters, including a 100km triangular closed circuit speed of 88.8mph in Switzerland flown by Klaus Holighaus and U. Plarre on 15 August 1974, a women's goal and return flight record of 339 miles in Italy in April 1976, flown by Adele Orsi and M. Monti, and further speed records over 100km, 300km and 500km triangular closed circuits in South Africa in November 1977.
In 1996 two variants were being built when the Janus was retired from production. The Janus Ce and/or Janus CT were both equipped with 20 m carbon fiber wings, absorbed horizontal tail unit, larger vertical stabilizer and more effective airs brake. Earlier designs had the GRP wing with 18,2 m span - however the JANUS von Anbeginn had curving flaps
A French development of the Janus is the SCAP-Lanaverre SL-2 all-plastics sailplane created by SCAP-Societede Commercialisation Aeronautique du Plessis, SàRL and Lanaverre Industries, the latter building the Standard Cirrus under licence from Schempp-Hirth. First flown on 15 October 1977, the SL-2 differs from the Janus chiefly in having provision for 30.8 Imp gallons (140 litres) of water ballast in the wings and a fixed tailplane with elevators instead of a one-piece all-moving tailplane; a more comfortable cockpit for the two pilots is provided, with provision for back-type parachutes.
Span: 59 ft 8.5 in / 18.2m
Length: 28 ft 3.25 in
Height: 4 ft 9 in
Wing area: 178.5 sqft
Aspect ratio: 19.97
Empty weight: 838 lb
Max weight: 1,366 lb
Max ballast: 200 lb
Vne: 119 kts
Max speed: 136 mph (in smooth air)
Stall 10 deg flap: 38 kt
Max aero-tow speed: 105 mph
Min sinking speed: 2.30 ft/sec at 56 mph
Best glide ratio: 39.5:1 at 68.5 mph / 59 kt