The development of this aircraft began in the spring of 1960 as part of the effort to upgrade the Su-11 (T-47) interceptor, fitted with the AL-7F-2 type engine, based on the solutions developed under the scrapped T-3M (T-37) fighter/interceptor programme. The project was given the name Su-15 and work-in-progress designation T-58. The upgrading project provided for the aircraft to be given a capability to intercept targets at a wider range of altitudes and flight speeds, including in head-on approach (forward hemisphere interception). Moreover, the research scope covered an option of rendering all major intercepting procedures automatic, with an autopilot system specified for the aircraft.
The T-58 initial configuration underwent a radical transformation compared to the T-47: for the nose to accommodate a higher-performance radar, the axial nose air intake with shock-cone centre body was replaced on the new fighter with lateral variable ramp intakes with a vertical airbrake. Later on, in the context of the requirements to improve the aircraft's reliability, the single-engine configuration was discarded in favour of a configuration with two R-11F-300 type engines. As a result, the Su-15 acquired the streamlined look of a classic supersonic fighter of the class of 2nd-generation jet aircraft.
The building of a prototype was completed early in 1962, with the maiden flight of the T58D-1 prototype taking place 30 May 1962 (test pilot V.S. Ilyushin). The aircraft's State Integration Tests (SIT) were conducted under a tight schedule between August 1963 and June '64; unlike the tests on the Su-9 and Su-11, they were completed without any serious faults found. The SIT findings cited low range as the only material weakness. To remedy the situation, the Su-15 was provided with increased fuel tankage, its fuselage having been streamlined at the wing roots and the "waistline" featured on the prototypes taken in. On 30th April the aircraft was put into service as part of the Su-15-98 intercept capability based on the Su-15 (T-58) host aircraft, a weapons system with RP-15 (Oryol-D-58) radar unit and R-98 rockets in two variants: with semi-active radar target seeker and passive IR target seeker, as well as a ground-based component, the Vozdukh-1M type guidance system. This way, the Su-15 became the Design Bureau's third interceptor, after the Su-9 and Su-11, to be mass-produced and put into service as part of an intercept capability.
The Su-15 went into production in 1966 at a plant in Novosibirsk where it replaced the YaK-28P on the production line. The maiden flight of the Su-15 pre-production prototype took place on 6th March 1966, with the plant's test pilot I.F. Sorokin at the controls. In 1967, the planes began to be delivered to combat units of the ADF. The first unit in USSR's Armed Forces to be rearmed with the Su-15 was the fighter aircraft regiment of the ADF Moscow district, which was deployed at the Dorokhovo airfield. It was not until after production had started that the Su-15 received a boundary layer blowing control (BLBC) system to improve its takeoff and landing characteristics.
A training version of the aircraft (U-58T) was built at Novosibirsk in 1968; on 28th August 1968, the design bureau's test pilot Ye.K. Kukushev performed its first flight. The official tests were completed in 1969; in 1970, the aircraft entered service under the designation Su-15UT and was in production till the end of 1971.
Beginning in the mid '60s, the Design Bureau did work on upgrading the baseline version of the Su-15 to improve its combat performance, viz., to increase its identification/engagement range; with this end in view, the aircraft was to receive a new Taifun radar (a Smerch radar upgrade) and more lethal rocketry. The new version became known as the Su-15T (manufacturer's designation T-58T). In addition, at the request of the military, the aircraft was provided with an air-to-ground capability (bombs, unguided rockets and gun pods). A prototype aeroplane with the new equipment was built in late 1968, its maiden flight performed by test pilot V.A. Krechetov on 31st January 1969. The official tests took place in the period 1969-73, and on 21st January 1975 the aeroplane was put into service as part of the Su-15-98M upgraded intercept capability, the Su-15T(TM) being produced at the Novosibirsk plant in the period 1970-76.
In early 1976, there was built a prototype of an upgraded two-seat aircraft, the Su-15UM, its first flight performed on 23rd April 1976 by the plant's test pilots V.T. Vylomov and V.A. Belyanin. The testing of the aircraft was completed in November 1976; the Su-15UM was produced through 1981.
A total of about 1,300 Su-15-type aeroplanes were produced at the Novosibirsk aircraft plant. There were no operational upgrades of the Su-15 to speak of, unless we count the fact that in the late '70s - early '80s the entire operational stock of the machines underwent modification to accommodate 2 R-60-type close-in action rockets suspended underwing on additional pylons.
In the late '60s - early '70s, the Su-15 interceptors together with the Su-9 and Su-11 formed the fist of the air arm of the USSR ADF troops as mainstream state-of-the-art interceptors. By the mid-'70s, i.e., during the period of peak deployment, the Su-15 was in the inventory of 29 fighter aircraft regiments, which accounted for more than a third (!) of the operational air units of the ADF troops.
Su-15 (Su-15TM) type aeroplanes were kept in the inventory of the ADF troops and USSR Air Forces till 1991; in the inventory of the RF Armed Forces, till 1994; in Ukraine, through 1996. The last combat unit to be equipped with Su-15 type planes was the aviation regiment of Ukraine's Armed Forces stationed at the Belbek aerodrome in the Crimea.
Su-15 type aircraft were instrumental in intercepting a great number of intruders into the USSR’s airspace. The first of such intercept engagements on Su-15 took place in 1970, when on the night of 11th September a pilot of the 62th FAR escorted to his home airfield a Greek Douglas DC-3.
The widest media coverage was given to 2 instances of "shoot-down" deployment of the Su-15. The first incident took place on 20th April 1978 in Karelia, when a South Korean Boeing 707, en route from Paris to Anchorage, violated the USSR’s airspace around Murmansk. The intercept mission of a Su-15TM aircraft was flown by a pilot of the ADF's 431st FAR, Cpt A.I. Bosov. All attempts to persuade the Boeing 707 into a forced landing having failed, the pilot was ordered to shoot down the intruder and fired a R-98MR missile at it, following which the damaged Boeing landed on the iced over Korpiyarvi lake. In the course of the incident fragments from the exploding rocket killed 2 passengers and wounded 10.
The second incident took place on the night of 1st September 1983, when another passenger jet, a Boeing 747 flying the Anchorage-Seoul route, was intercepted and shot down in the Far East. The action to intercept the aircraft, which had strayed into USSR airspace over Kamchatka and Sakhalin involved, among others, a pilot of the 777th FAR, Major G.N. Osipovich, who took the Su-15 aircraft on alert off the ground and was ordered to shoot down the intruder. It is believed that the incident brought about the death of 269 people onboard the Boeing 747.
What is less known is the fact that a Su-15 was used to perform a successful ramming manoeuvre. On 18 July 1981, the USSR's Transcaucasian airspace was penetrated by a CL-44 type transport aeroplane inbound from Iran. The intercept mission was flown by two of the 166th FAR's Su-15s, one of the planes piloted by Cpt V.A. Kulyapin. Given the time constraints of the situation, with the intruder about to escape across the border, Kulyapin, having been ordered by ground control to prevent it, had to engage by ramming it, following which he succeeded in saving himself by ejecting. The pilot was decorated with the Order of the Red Star for his heroism.
The Su-15 aircraft was used as a platform to develop and test at the FRI and Design Bureau's facilities a variety of flying laboratories (FL). For example, the first prototype was used in 1966 to build an experimental STOL plane, the T-58VD, equipped with a powerplant of two R-11 type operational main engines and three additional RD-36-35 type lift booster engines. T-58VD was used for development testing of reduced takeoff and landing modes and was demonstrated during the air pageant in the summer of 1967. A second prototype of the Su-15 was converted into the experimental T-58L, to be used for improving performance on unpaved runways. Its design provided for an option of replacing the major landing gear wheels with skis. At the beginning of the '70s, the Su-15 was used to try out a pilot refuelling system, with 3 planes converted into FL for the purpose: two Su-15s to accommodate a Sakhalin-type UPAZ buddy tank, and one Su-15T fitted with a non-retractable refuelling probe. The system was flight-tested in the period 1972-76.
