Boris N. Yuriev
As a student in Moscow, Boris N. Yuriev (1889–1957) constructed one of the first single main rotor/tail rotor helicopters in 1912; during ground tests, however, the main rotor shaft failed due to flexure. He later became revered as one of the greatest Russian scientists in helicopter aerodynamics and the founder of Soviet helicopter production.
In 1925, Yuriev was put in charge of helicopter research at the Central Aero-Hydrodynamic Institute (TsAGI). The first flying Soviet helicopter was the 1-EA – it reached an altitude of 610 m (2,000 ft) and had an endurance of 14 minutes.
Source: 2013 AHS Calendar