Civil Aviation Department of India HS-1 / HS-2 Mrigasheer
To succeed the earlier KS-II Kartik high performance single-seater the Technical Centre started design of another Standard Class sailplane known as the HS-1 Mrigasheer (मृगशिरा - "Orion"). The HS-1 is a single-seat Standard Class sailplane designed and developed at the Technical Centre by the team of designers and engineers led by Mr K. B. Ganesan, Director of Research and Development.
It was an orthodox design with a high wing, slender, tapering fuselage, and conventional empennage. Construction was wooden throughout.
The original version, the HS-1, made its first flight in November 1970. This had a higher aspect ratio wing than the Kartik's with Wortmann wing sections instead of the earlier design's NACA 64-series aerofoils. This was further developed into the HS-2 Mrigasheer under a design team lead by Mr K. B.Ganesan the centre's Director of Research and Development, and the prototype of this made its first flight in April 1973. The following month it was flown into second place in the first Indian national gliding championships held at Kanpur. A second prototype, based on the aerodynamic design of the first, made its first flight in May 1977; this has trailing edge slotted flaps instead of the first prototype's upper surface air brakes, and a glassfibre reinforced plastic tailplane and elevators of different aerofoil section.
The Mrigasheer is of plywood-covered wooden construction and the high wings are two-spar structures with a plywood leading edge torsion box and plywood covering aft of the main spar, the wooden flaps and ailerons being hinged on the rear spar. The semi-monocoque fuselage is plywood-covered, as is the fin, but the rudder is fabric covered. There is a retractable unsprung monowheel with a drum-type brake, as well as a rubber-sprung nose skid with a replaceable steel shoe and a similarly sprung tail skid. The pilot sits under a long forward-opening jettisonable one-piece canopy.
The HS-2 differed from its predecessor in having slotted flaps instead of airbrakes, and a completely redesigned tail. This has glassfibre-reinforced plastic horizontal tail surfaces of different aerofoil section.The wooden two-spar wings incorporate a plywood leading edge torsion box with plywood covering aft of the main spar. The rear spar carries the hinges of the wooden flaps and ailerons. The fuselage consists of a semi-monocoque wooden structure with plywood covering.
Length: 7.59 m (24 ft 11 in)
Wingspan: 15.00 m (49 ft 3 in)
Height: 2.50 m (8 ft 3 in)
Wing area: 11.24 sq.m (121.0 sq ft)
Aspect ratio: 19.9
Wing section: Wortmann FX-61-184/163/60-126
Empty weight: 237 kg (522 lb)
Gross weight: 335 kg (739 lb)
Water ballast: None
Max wing loading: 29.54 kg/sq.m (6.05 lb/sq.ft)
Maximum speed: 213 km/h / 133 mph / 115 kt
Max rough air speed: 80 kt (148 km/h)
Max aero-tow speed:71.5 mph
Maximum glide ratio: 32
Rate of sink: 0.58 m/s / 120 ft/min / 1.9 ft/sec
Crew: One pilot