This utterly slick thing was Matus Bisnovat’s OKB contribution to the plethora of stunning high-speed aircraft made around the world at the end of the 1930’s-early 1940’s. His SK-1 all-metal research aircraft was conceived following the classic formula of the smallest airframe possible powered by the more powerful engine at hand -a 1050hp Klimov M-105 in this case. The SK-1 took the skies in January 1939 and soon demonstrated its superb qualities in both speed and handling. So good it was that a fighter derivative was soon developed from it, the SK-2.
Such a racy thing. In search of aerodynamic efficiency just a small low-drag radiator installation was employed due to its pressurised coolant system. It had also a incredibly cool flush cockpit equipped with a hydraulically raised pilot seat and canopy roof , the latter became a “windshield” during landings.