able to exploit thermals to set local records. Though the details of most of these flights are lacking, the high performing S.15C Milan recorded one of over three hours. Ten S.15Ks remained on the Swiss register into the 1950s, a few flying on to the end of the 1960s. Two were sold to Belgium in 1951 and one of these, originally HB-449 but OO-ZIW after its move, was restored to flight in 2015 as HB-449 again. In 2019 it is the only Spalinger S.15 flying. Variants S.15 First flight 1930, span, aspect ratio 17. S.15A Austria II 1932, span, aspect ratio 9.6. Intended for basic instruction. Construction begun in 1930 but not completed. S.15B First flight 1933, span. An enlarged S.15A intended for advanced instruction and performance. 2 built. S.15C Milan First flight 28 March 1932, from Milan. span, aspect ratio 17. 1 built. S.15K First flight 1934. Gull wing with span, aspect ratio 15. Only production variant, 21 built. Specifications (S.15K) References Gull-wing aircraft 1930s Swiss sailplanes Aircraft first flown in 1930