The Su-11 is a modernized derivative of the Sukhoi Su-9 with a more advanced engine, the new Oriol-radar and modified armament. After testing with new variants of the T-3 prototype, called PT-7, PT-8 and T-47, the first flight of the prototype, which was called T-47-8, was in 1961.
Su-11 has many design features of the Su-9, like the delta wings, the stabilizators and the fuselage design. The difference between the Su-9 is the nose, which is somewhat larger than on it’s precursor, to make room for the larger Oriol-radar (NATO codename: “Skip Spin”), and only two external hardpoints. The more powerful Lyulka AL-7F-engine with a better afterburner and a maximum thrust of 98 kN was included. Even if the new engine was heavier than the old one, the Su-11 had better performance on great altitude and a better rate of climb in comparison to the Su-9.
The Su-11 was equipped two R-98 (AA-3 Anab) Air to Air missiles, the weapon complex was called K-8, which is composed of a radar guided R-98MR and a heat seeking R-98MT. Like most of the Interceptors at this time, the Su-11 wasn’t equipped with a machine gun.
Production of the Su-11 begun in 1962, the definitive aircraft were called Su-11-8M (because of the K-8M missiles). The first aircraft were sent to the squadrons in June 1962. The crash of an aircraft during testing led to negative views in the Russian Air Force and it was wanted to cancel the program to promote the Jak-28P. Finally, it was agreed to produce it, after some modifications, in small numbers only. 1963/64 it was modified and again tested and in May 1964, the first Su-11 entered service. At the beginning of 1965, the last of the 108 Su-11 was built, depending on some sources, some of the Su-9 were also upgraded to Su-11. The Su-11 was replaced by the Su-15, but some of them remained operational until the end of the 1970s.