Schempp-Hirth Standard Cirrus

Dipl Ing designed the Standard Cirrus. Klaus Holighaus 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, so modifications were made to the early design. The aircraft built before 1972 have a washout of -0.75 degrees. The washout was then increased to -1.5 degrees, improving low-speed performance and slow-speed response. Improvements were made to 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 of Schempp-Hirth ended, 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 licensed-built Standard Cirruses, reaching approximately 100 by 1985. ==Variants==

;Baby Cirrus The Baby Cirrus is similar to a Standard Cirrus 75. The only difference is that the Baby Cirrus 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 to 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 this day 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 a larger elevator, and a strengthened fuselage, which makes them suitable for aerobatics. This modification was initiated by Wilhelm Düerkop in the late 1980s. Wolfgang Seitz participated in the 1995 World Glider Aerobatic Championships with a Cirrus K. ;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. ==Specifications==