The Standard Cirrus was designed by Dipl. Ing. Klaus Holighaus and flew for the first time in February 1969. It is a Standard Class glider with a 15-metre span, and laminar-flow airfoil section designed by Professor Franz Wortmann. The all-moving tailplane, a feature of many designs of that period due to its theoretically higher efficiency, caused less than desirable high-speed stability characteristics, and so modifications were made to the early design. Even so, the glider is still very sensitive in pitch. The aircraft built before 1972 have a washout of -0.75 degrees. The washout was then increased to -1.5 degrees which improved low-speed performance and response at slow speed.^[1]

Improvements were made with the Standard Cirrus 75. These included better air-brakes with an increased frontal area and a safer tailplane attachment system. By April 1977, when production by Schempp-Hirth ended, a total of 700 Standard Cirruses had been built, including 200 built under licence by Grob between 1972 and July 1975. A French firm, Lanaverre Industrie, had also built 38 Standard Cirruses under licence by 1979. VTC of Yugoslavia also licence-built Standard Cirruses, reaching approximately 100 by 1985.

Baby Cirrus

The Baby Cirrus is similar to a Standard Cirrus 75. The only thing different about them is the fact it had its wing on top of the fuselage mounted on a fiberglass beam of some sort. Only one was made. It was primarily used to try and improve the design of the Standard Cirrus. The original registration was D-3111. It was later converted to a Standard Cirrus 75 and was given a new registration. It is still flying to the day of this edit and is owned by a club in Germany.

Cirrus B

The Cirrus B is based on the Standard Cirrus 75 but with interchangeable wingtips giving a span of either 15m or 16m.

Cirrus K

The two Cirrus K have a reduced span (12.6m), larger ailerons, a cross tail with larger elevator, and a strengthened fuselage which make them suitable for aerobatics. This modification was initiated by Wilhelm Düerkop in the late 1980s.^[2][3] Wolfgang Seitz took part in the 1995 World Glider Aerobatic Championships with a Cirrus K.^[4]

G/81

The last Cirrus model was the G/81 built by VTC until 1985. This incorporated a longer fuselage and canopy, and a conventional tailplane and elevator with the wings of the Cirrus 75.

Data from Jane's all the World's Aircraft 1976–77 ^[5]

General characteristics

• Crew: 1
• Capacity: 80 kg (180 lb) water ballast
• Length: 6.35 m (20 ft 10 in)
• Wingspan: 15 m (49 ft 3 in)
• Height: 1.32 m (4 ft 4 in)
• Wing area: 10 m² (110 sq ft)
• Aspect ratio: 22.5
• Airfoil: root: Wortmann S-02-196 (19.6%) ; tip: Wortmann FX 66-17A II 182 (17%)^[6]
• Empty weight: 215 kg (474 lb)
• Max takeoff weight: 390 kg (860 lb) with water ballast

330 kg (730 lb) without water ballast

Performance

• Stall speed: 62 km/h (39 mph, 33 kn)
• Never exceed speed: 220 km/h (140 mph, 120 kn)
  
• Max aerotow speed: 150 km/h (93 mph; 81 kn)
• Max winch launch speed: 120 km/h (75 mph; 65 kn)
• g limits: +10
• Maximum glide ratio: 38.5:1 at 90 km/h (56 mph; 49 kn)
• Rate of sink: 0.6 m/s (120 ft/min) at 71 km/h (44 mph; 38 kn)
• Wing loading: 39 kg/m² (8.0 lb/sq ft) with water ballast

33 kg/m² (6.8 lb/sq ft) without water ballast

Related development

• Schempp-Hirth Discus

Aircraft of comparable role, configuration, and era

• Bölkow Phoebus
• Glasflügel H-201 Standard Libelle
• Rolladen-Schneider LS1
• Schleicher ASW 15

Related lists

• List of gliders

Citations edit

Bibliography edit

• Schempp-Hirth Website
• Coates A.,Janes World Sailplanes and Motor Gliders, Janes,1980, ISBN 0710600178, pg. 85
• Simons M, Segelflugzeuge 1965–2000, Eqip, 2004
• Sailplane Directory
• American narrative of World Championships (see 1968).