In 1948, the Soviet MiG design bureau developed a high-performance jet fighter design called the I-310. It incorporated some advanced features, such as a 35-degree wing sweep, and it promised to be a sprightly performer. However, the design lacked one essential component: A suitable engine. This problem was resolved when the British government authorized the Rolls-Royce company to export their Nene turbojet engine to Russia. As soon as the Russian Klimov design bureau received the engines, they immediately developed their own copy of the Nene, called the Klimov RD-45. Within months, the first prototype of the I-310 had flown with the new engine. The aircraft was re-designated MiG-15 and entered service early in 1949.
Later in the year, the improved MiG-15bis version appeared, and a two-seat trainer version, the MiG-15UTI, was also introduced. In 1950, Western air forces were surprised at the combat capability of the new design in the skies over Korea. The MiG-15 could out-climb, out-turn, and fly higher than the US-built F-86 Sabre. Fortunately, Allied pilots were better-trained and had better equipment installed in their aircraft, and they prevailed against the MiG.