Within an unusually short timescale, the Pavel Sukhoi OKB succeeded in developing a successful limited all-weather single-seat interceptor fighter from the T-3 and its immediate derivatives. Assigned the designation Su-9, this interceptor was available to enter IA-PVO Strany service from 1961. The Su-9 was directly evolved from the T-4 series of prototypes, which, sharing the 57° delta wing and Lyulka AL-7F turbojet with the preceding prototypes, differed from one another in detail design, systems and equipment. With a single exception, the T-4 prototypes featured a circular nose intake with a translating centrebody to accommodate the S-band R1L search-and-track radar. The exception, the T-49, had a unique arrangement of box-type intakes flanking a slim, ogival nose radome.

The first T-4 series prototype, apparently designated T-401, entered flight test during 1957, and, in May 1960, an essentially similar aircraft, the T-405, established a new 100km closed-circuit record of 2092km/h. The definitive fighter development, the T-43, was first flown in 1958 as the T-431, and established a zoom climb altitude record of 28,850m on 14 July 1959. Three years later, the T-431 set both a sustained altitude record of 21,170m and a 500km closed-circuit record of 2337km/h.

Series production of the T-43 as the Su-9 was launched in 1959, standard armament comprising four beam-riding K-5 AAMs on underwing pylons. Production of the Su-9 is believed to have exceeded 1,000 aircraft, and this type remained in Soviet service until the beginning of the 'eighties.

3-View

A three-view drawing (1670 x 1067)