Sergey Alekseevich
Chaplygin

1869-1942


Sergey Alekseevich Chaplygin was a Soviet scientist in the field of theoretical mechanics and hydroaerodynamics, Academician of the USSR Academy of Sciences, Honored Worker of Science and Technology of the RSFSR. He was born in the city of Ranenburg, now it is the city of Chaplygin, the Ryazan region. The father of the future scientist served as a salesman in a shop. After his death in 1871, his mother and three children moved to Voronezh. After finishing Voronezh Gymnasium with a gold medal in 1886, he entered the Physics and Mathematics Faculty of Moscow University. During his studies, he began his first scientific work on hydrodynamics “On the movement of heavy bodies in an incompressible fluid”. This study was presented in 1890 as a thesis. After a successful defence, on the recommendation of N.E. Zhukovsky, he was left at the university to prepare for a professorship. In 1894 he became a privatdozent of Moscow University. The first works of the scientist, created under the influence of N.E. Zhukovsky, belong to the field of hydromechanics. They describe the geometric interpretation of the laws of motion of solids in a liquid, discovered in a number of studies by Russian and foreign scientists. In 1898 he defended his master’s thesis with the scientific work “On some cases of motion of a solid body in a liquid”. In 1903 he defended his doctoral dissertation “On gas jets”, in which a method for studying jet movements of gas at any subsonic speeds was proposed. This work marked the beginning of a new branch of mechanics – gas dynamics, which later played a huge role in the development of aviation. From 1893 he taught physics at women’s secondary schools, at Moscow Higher Technical School and Moscow Engineering School. Since 1901 he was a Professor of mechanics at Moscow Higher Women’s Courses, since 1903 – a Professor at Moscow University in the Department of Applied Mathematics. In 1905-1918 he was the Director of Moscow Higher Women’s courses. In February 1911 Chaplygin left Moscow University together with a large group of professors in protest against the actions of the Minister of Education Kasso. During the Civil War, Professor Chaplygin worked in the Commission on Artillery Experiments at the Main Artillery Directorate of the Red Army (Kosartop) and at the Scientific Experimental Institute of Railways. In 1917-1922 he was again a professor at Moscow University, but left it to concentrate on scientific work. In 1918, the Central Aerohydrodynamic Institute (TsAGI) was organized in Moscow. S.A. Chaplygin was one of its leading researchers. In 1921, after the death of the founder and first head of TsAGI, N.E. Zhukovsky, Chaplygin became the chief scientific director and chairman of the TsAGI board (1921-1930). In 1928-1931 he was the Director (head) of TsAGI. In the 1930s, the scientist’s work became more applied. In 1931-1941 he led the creation of the largest aerohydrodynamic laboratories of TsAGI. In the early 30s, under the leadership of Chaplygin and his student M.V. Keldysh, research was conducted on the theory of flutter, which was later used in the design of high-speed aircraft. Since 1940, Academician Chaplygin was the chairman of the TSAGI Problem Commission on gas dynamics. Chaplygin’s works became the basis for solving problems about subsonic currents and allowed solving the main problems associated with the operation of the wing at high subsonic speeds, and other problems of modern aerodynamics. He solved a number of complex problems of aeromechanics and aviation, which greatly contributed to the development of the theory of stability of the aircraft wing in flight. For the first time, he derived formulas for unsteady wing movement – on takeoff and landing, which was of great importance for practical aerodynamics. For outstanding scientific achievements in 1926, S.A. Chaplygin was elected a corresponding member of the USSR Academy of Sciences, and on January 12, 1929 – an Academician of the USSR Academy of Sciences. Since 1933 he was the Chairman of the Group of equipment of the USSR Academy of Sciences, since 1937 – the Chairman of the Commission on Hydromechanics and Aerodynamics of the USSR Academy of Sciences.

Address: Moscow, Maly Kharitonyevsky Lane.