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BIOGRAPHIES OF GREAT SCIENTISTS
Chaplygin Sergey Alekseevich. Biography of a scientist
Directory / Biographies of great scientists
He was already an adult when aviation was just taking its first timid steps. Together with another great Russian scientist Zhukovsky, Chaplygin stood at the origins of aviation science, creating the theoretical foundations of aeronautics. He is one of the founders of modern aerohydrodynamics. Sergei Alekseevich Chaplygin was born on March 24 (April 5), 1869 in the Ryazan province in the city of Ranenburg. The father of the future scientist, Alexei Timofeevich, served as a shop assistant, and his mother, Anna Petrovna, a beautiful, kind woman, kept house. Parents lived together, but family happiness did not last long. When Seryozha was two years old, his father died of cholera, which then raged in those places. After some time, at the insistence of her parents, Anna Petrovna remarried and moved with her son to Voronezh, where her new husband Semyon Nikolaevich Davydov worked at a leather factory. Serezha grew up as a thoughtful, serious boy beyond his years. He early learned to read and count, with pleasure he helped his mother with the housework. The stepfather treated his stepson well. Upon learning that his mother wanted to give her son an education, he brought a seminarian he knew to the house, who undertook to prepare Seryozha for entering the gymnasium, and the boy passed the entrance exams. Outstanding abilities and a brilliant memory helped. Davydov turned out to be a bad family man and left Anna Petrovna alone with five children in her arms. Additional cares fell on the elder Sergey. After classes at the gymnasium, he ran home to help his mother with the housework, and then went to give lessons. Sergey studied perfectly, everyone knew about his extraordinary abilities and invited him to study with his lagging children. Sergei taught the sons of wealthy citizens mathematics, German and Greek, and Latin. At the age of thirteen, he became the breadwinner of the family. After graduating from the gymnasium in 1886 with a gold medal, Sergei entered the Faculty of Physics and Mathematics of Moscow University. He studies diligently, does not miss a single lecture, although he still has to give private lessons to earn his living. He sends most of the money to his mother in Voronezh. Sergei lives from hand to mouth, often he does not even have three kopecks for a horse, and he has to get to lessons from end to end of Moscow on foot, but he does not complain, but persistently masters the sciences. Best of all, of course, he knew his favorite subjects - mathematics, physics, astronomy, mechanics. They were read to him by such famous scientists as B. K. Mlodzeevsky, A. G. Stoletov, F. A. Bredikhin, N. E. Zhukovsky. Entering the university, Sergei thought to specialize in pure mathematics, but under the influence of Professor Zhukovsky's lectures, he became interested in mechanics. Nikolai Yegorovich Zhukovsky immediately drew attention to the brilliant abilities of Sergei Chaplygin, whom he met at lectures. On the advice of his beloved professor, Chaplygin begins his first scientific work on hydrodynamics, "On the Motion of Heavy Bodies in an Incompressible Fluid." This study, presented in 1890 by Chaplygin as a thesis, was awarded a gold medal by the university. At the suggestion of Zhukovsky, Sergei Chaplygin was left at the university to prepare for a professorship. He was awarded a scholarship in the amount of fifty rubles a month. So the first scientific work of Chaplygin determined his future life. While working on his dissertation, Chaplygin simultaneously begins teaching. Initially, from 1893, as a teacher of physics in one of the secondary educational institutions in Moscow, and from 1894, he became a Privatdozent at Moscow University. There are changes in the personal life of Sergei Alekseevich. In the autumn of 1894, he marries his landlady Ekaterina Vladimirovna Arno. On August 3, 1897, their daughter Olga was born. The second scientific work of the young scientist "On some cases of motion of a rigid body in a liquid", published in 1897, was defended by him the following year as a master's thesis. In it, he gave a geometric interpretation of the laws of motion of solid bodies in a liquid, which had previously been found in analytical form by some Russian and foreign researchers. Zhukovsky praised Chaplygin's work as a classic. Sergei Alekseevich paid much attention to work with students. At various times, he taught at many Moscow higher educational institutions: the university, higher technical, engineering and commercial schools, forestry and land surveying institutes, at higher women's courses, the organizer and director of which he was in 1905-1918. He wrote the textbooks "Mechanics of the System" (1905-1907) and "Propaedeutic Course of Mechanics" (1915) for technical colleges and natural faculties of universities. Chaplygin continues to conduct great scientific work. He is interested in the motion of solid bodies on a rough surface. As a result, two studies appeared: "On the motion of a heavy body of revolution on a horizontal plane" and "On some possible generalization of the area theorem with application to the problem of rolling balls", for which in 1900 Sergei Alekseevich Chaplygin was awarded the St. Petersburg Academy of Sciences with an honorary gold medal. At the turn of the century, Chaplygin began to study jet flows in incompressible, and then in compressible liquids. In 1895, he made a report "On the motion of gas with the formation of a gap" at a meeting of the Moscow Mathematical Society, and in 1903 he defended his doctoral dissertation "On gas jets", in which he proposed a method for studying jet motions of gas at any subsonic speeds. Briefly, the essence of the work "On gas jets" is as follows. When a body moves in a stream of air, it experiences aerodynamic drag. This resistance is greater, the greater the speed of movement. Chaplygin showed that for speeds not exceeding 100 m/s, the aerodynamic drag is proportional to the square of the speed. If the speed approaches the speed of sound (in air it is approximately equal to 331 m / s), then to find the magnitude of the frontal resistance, it is necessary to solve another differential equation, which is now called the Chaplygin equation. The effectiveness of the method proposed by the scientist for calculating flat gas flows made this work the most outstanding research on gas dynamics in half a century of its development. This work stands apart in the work of the scientist, and its fate is unusual. She remained misunderstood and unappreciated by her contemporaries for a long time. At the time when aviation was taking its initial steps, the scientist wrote about movement at speeds close to the speed of sound. In addition, the work was written briefly, concisely, and difficult to understand. But it is not for nothing that they say that there is nothing more practical than a good theory. In 1935, in Rome, at a conference on high speeds in aviation, foreign scientists got acquainted with the work of Chaplygin and called it the best research in the field of gas dynamics in terms of accuracy, originality and elegance of the method. Forty years after the appearance of Chaplygin's work, aircraft began to fly at speeds close to the speed of sound. For engineers, designers and developers of aviation technology, the scientist's work has become a desktop reference. Shortly after defending his doctoral dissertation, Chaplygin was elected a professor at Moscow University. In 1910, the scientist made a presentation at a meeting of the Moscow Mathematical Society, in which he showed how the circulation can be calculated when the air flows around the wing. Thus, if Zhukovsky took the first fundamental step in explaining the origin of the lift force of an aircraft wing, then Chaplygin took the second fundamental step, showing how the real lift force of an aircraft wing can be calculated. In 1911, student unrest took place at Moscow University. They were brutally suppressed by the then minister of education Kasso. In protest against the massacre of students, all the best professors and teachers left the university, including Chaplygin. After the Great October Socialist Revolution, Sergei Alekseevich returned to the university. It was a difficult time. Trams did not run, and professors and students traveled to classes on foot. The university building was not heated, and in the classrooms everyone sat in coats and hats. But, despite these difficulties, the life of the university went on as usual. Teachers at exactly the appointed time entered the classroom and began classes with the then few students. In addition to teaching at the university, Sergei Alekseevich continues to engage in research work. Since 1918, he has been participating in the work of the Commission for Special Artillery Experiments at the Main Artillery Directorate and in the work of the Scientific Experimental Institute of Communications. The country of the Soviets needed aircraft, and in 1918 the Central Aerohydrodynamic Institute (TsAGI) was organized in Moscow. Zhukovsky is appointed director, who attracts Chaplygin to work. Nikolai Yegorovich instructs him to manage the TsAGI branch in Kuchino near Moscow. Unfortunately, their cooperation at TsAGI did not last long. In 1921, the "father of Russian aviation" dies, and Chaplygin becomes the chief scientific director and chairman of the TsAGI collegium. The building of the Aerohydrodynamic Institute has not yet been completed, and Sergei Alekseevich spends a lot of time at the construction site. Under his leadership, various testing laboratories, a design bureau and even a pilot plant were created, where it was possible to build aircraft. At the same time, he is doing a lot of scientific work. At this time, he wrote studies: "On the General Theory of the Monoplane Wing" (1920), "The Schematic Theory of the Split Wing" (1921), "On the Effect of a Plane-Parallel Air Flow on a Cylindrical Wing Moving in It" (1926). Back in 1914, Chaplygin completed the study "The Theory of the Lattice Wing", which was also decades ahead of its time. In it, Chaplygin came to a seemingly paradoxical conclusion: a louvered wing has more lift and is more stable in flight than a solid wing of the same size. This was a significant contribution to the theory of the airplane wing. In addition, Chaplygin's work was also important for the theory of hydraulic machines. President of the Academy of Sciences of the USSR M. V. Keldysh assessed it as follows: "The Lattice Wing Theory, which lays the foundations for the theory of circulating flow around lattices, is the basis for calculating propellers, turbines and other hydraulic machines." In his Schematic Theory of a Split Wing (1921), he continues to reflect on the problem of a composite wing and indicates how the aerodynamic qualities of a wing can be improved and its lift force can be increased. If the wing in the form of an arc of a circle is cut into two parts and spread them apart properly, then the lift force of such a split wing will be greater. In 1931, Chaplygin, together with his student N. S. Arzhanikov, wrote the work "On the Theory of the Opener and the Flap", as if completing this topic. What was the value of these works? The lower the speed of the aircraft, the easier it is for him to land, the safer it is. Hence the desire - to fly at high speed, and land at low speed. But low speed means low lift. With insufficient lift, the aircraft may fall to the ground and crash. Therefore, it is necessary to increase the speed so that the plane stays in the air. It turns out a vicious circle. Chaplygin's work helped break this circle. The wings of modern aircraft have slats and flaps. By releasing them, the pilot increases the lift by 20, 50 or more percent, which allows him to land on the runway at a lower speed. It is interesting that this work was done at a time when not a single aircraft had composite wings. There was no need for them, since landing speeds were low. As the flight speed increased, so did the landing speed. Now all modern aircraft have wings with controlled flaps and flaps, which allow, without reducing the flight speed, to reduce the landing speed of the aircraft. Sergei Alekseevich in his works, as always, went ahead of his contemporary technology. Lattice wings are currently installed on the Soyuz spacecraft (this is an element of the emergency rescue of the cabin with astronauts), on hydrofoil ships, and on sea ships to stabilize them during pitching. Now composite and lattice fenders are a common feature of many transportation systems. Chaplygin's scientific activity put him forward to one of the first places among the scientists of the Soviet Union, and in 1926 he was elected a corresponding member of the USSR Academy of Sciences, and on January 12, 1929 - an academician. The huge administrative work that Chaplygin did as director-head of TsAGI took a lot of energy, and in 1931 the scientist asked to be relieved of his post for health reasons. The request was granted, but Chaplygin continued to work at TsAGI until the last days of his life. He was the head of the general theoretical group of TsAGI, and since 1940 he headed the aerodynamic laboratory, which now bears his name. In any weather, despite the senile ailments, he came to the laboratory at the appointed time, showing his young colleagues an example of true service to science. Employees noted his fairness, rigor and kindness. In 1933, Chaplygin was awarded the Order of Lenin, and in February 1941 he was awarded the high title of Hero of Socialist Labor. When the war began, Sergei Alekseevich was offered to leave Moscow, but he refused. In October 1941, the front came close to the capital. It was decided to relocate TsAGI to the east. Together with the institute, Chaplygin also left for Novosibirsk. At the new location, he led the work on the creation of a branch of TsAGI. Every day on the construction site one could see the elderly scientist giving clear and precise orders. Sergei Alekseevich died in Novosibirsk on October 8, 1942, not having lived to see the Victory, in which he firmly believed and for which he worked selflessly. The last words he wrote were: "While there is still strength, we must fight ... we must work." Streets in Moscow and Novosibirsk, a crater on the far side of the moon are named after Chaplygin. A monument was erected to him on the territory of TsAGI. The Academy of Sciences awards the prize to them. S. A. Chaplygin "For the best original work on theoretical research in the field of mechanics." Author: Samin D.K.
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