100th ANNIVERSARY IN THE HISTORY OF AVIATION: Jet-fighter La-160
28 June 2018
The study of the experimental fighter La-160 model aerodynamic performance in TsAGI’s wind tunnel Т-102 took place in 1947. This soviet sweptwing jet-fighter took to the air in June 1947. It was the first to have such a revolutionary configuration for the time, and was named the Strelka (Arrow) due to its distinctive appearance. It was the innovation of the S. A. Lavochkin Design Bureau and TsAGI scientists.
Strelka was created in the post-war years, which was characterized by a rapid development in aviation with the transition from propeller engines to reactive ones. The use of more powerful engines required a completely new approach to aircraft aerodynamics. So, it was decided to make it sweptwing, as well as reduce its relative thickness. The implementation of this idea required rigorous and complex studies — both theoretical and experimental.
During the War, TsAGI began working on the sweptwing architecture. Based on the results of theoretical calculations, the future academician Vladimir Struminsky showed the advantages of such a structure due to a sliding effect and wing shock wave reduction within the boundary layer. Furthermore, thanks to TsAGI research, swept wings have been provided with stall fences (chordwise) and wing fences preventing air flow passage along the bearing surface. This allowed an increase in the stall angle-of-attack values and an improvement in aileron effectiveness. TsAGI studies of the La-160 in wind tunnels covered a wide range of issues. In particular, it was revealed that swept wings allow displacing the crisis phenomena to a higher speeds area, soften their sharply changing character, as well as ensuring stability at high angles of attack.
The La-160 is a single-seat all-metal
Flight tests of the La-160 took place from June to September in 1947. Thanks to the large-scale flight tests of the La-160, a reliable database on stability and controllability peculiarities of the new configuration aircraft was obtained.
Strelka became the first Soviet aircraft to overcome the 1,000 km speed barrier: At an altitude of 5,700 m, test pilot I. E. Fedorov reached a speed of 1,050 km/h corresponding to Mach number 0.92. N. S. Chernyakov, the deputy of S. A. Lavochkin, remembered that day as follows: „The sound barrier was frightening aviation engineers all over the world in those days. It seemed impossible to overcome. While overcoming this barrier was the final goal of our activities for creating the La-160, it’s difficult for me to convey the excitement that we all felt, knowing well what kinds of danger were awaiting the aircraft and the test pilot.”
By circumstance, the La-160 was created in a single original. After the tests, it just took part in the air parade in Tushino in the summer of 1947.
The results of experimental studies of aerodynamic models and flight tests of Strelka became integral for creation of more sophisticated aircraft, such as the MiG-15 and La-15.