Originally designed, by the Mikoyan & Gurevitch (MiG) design bureau as an interceptor, the MiG-15 (NATO reporting name FAGOT) was the first jet combat aircraft flown by the Communist side during the Korean War. Equipped with relatively heavy but slow-firing cannon (1 37mm and 2 23mm) needed to kill heavy bombers, it was was quite competent against early U.S. jet fighters such as the F-80 Shooting Star. It should be considered a first-generation jet fighter.
Nevertheless, against the threat of the more competent F-86 Sabre air superiority fighter, the designers made changes that may not have improved its chances. MiG-15bis aircraft had a more powerful engine that could let climb faster and higher than the F-86. Given the lighter but faster firing machine guns of the F-86, which also had a lead-computing radar gunsight, the MiGs were at a distinct dogfighting disadvantage with the Sabre. When concentrated against bombers, it was effective. The MiG-17 was far more capable in air combat, but was not available in sufficient numbers to be significant in Korea.