"Pegaz" was designed by Stefan Gajęcki. The motor glider was flown on July 16, 1949, piloted by Bronisław Żurawski and Jerzy Szymankiewicz. At first, the plan was to build 80 "Pegazes" for the flying clubs. However it never was put into production, despite the fact that it passed the national approval test with a very good rating. The main reason for this was the order from the USSR to stop work on any national aviation project. In January 1948, Tadeusz Chyliński began work at the Technical Institute of Aviation (Instytut Techniczny Lotnictwa), renamed on April 1 of that same year as the National Aviation Institute (Główny Instytut Lotnictwa). From March 3, 1952, together with Zbigniew Brzoski, he worked as a designer at the Aviation Institute in the Department of Materials Science and Construction. There, he designed the fuselage, landing gear and tail rotor for the first Polish helicopter, the BŻ-1 GIL, whose main designer was the engineer Bronisław Żurakowski. In 1949 under the direction of Chyliński, the extensometer studies of the span of the Poniatowski bridge in Warsaw were completed. In 1951, he conducted these same studies on other bridge spans including on the Wisła in Knybawa and the intensity of stress on line insulators with high tension. In 1950, he reworked the Piper Cub airplane and made it into an ambulance airplane. The prototype was built at the Aviation Institute, and 14 of them were produced at the District Aviation Workshop No. 4 in Gdańsk. In the early 1950s, he designed target drones with pulsating propulsion TC1 and TC2 and in 1955, the towing drones Spec-3 and Spec-4 which were tested that same year. On 1 June 1951 he became the head of the Department of Material's Strength & Construction at the Polish National Aviation Institute in Warsaw. In February 1961, he graduated from Warsaw University of Technology (Politechnika Warszawska) and was awarded a master's degree in Aviation Engineering. During the years 1954-1956, he managed the Department of Airframe, and from 1956 until 1965-12-15, was the head of the Strength Department of the Aviation Institute further developing their labs and creating a new system of testing the strength of aviation equipment. In 1957, he developed, along with designers Justyn Sandauer and J. Harazny, an introductory project of a training airplane "As" as the comparative to the PZL TS-11 Iskra. From March 18, 1957 he was a member of the