Aircraft missile P-98 (K-98)

The K-98 medium-range aviation missile was designed as a deep upgrade of the K-8M missile and was intended for an improved version of the Su-11, the T-58 interceptor specified by the February 1962 Decree of the USSR CM.

The main focus of the K-8M upgrade was to ensure that the missiles could be launched not only from the rear but also from the front hemisphere, increasing interference immunity and combat efficiency. The first studies of the corresponding modification of K-8M-2 designed for use with T-3 and Yak-28 were carried out in 1961. Subsequently, the original name was changed to K-98 ("item 56").

In 1963, was released 31 missiles, launched flights IL-28, Tu-16 and Yak-28, confirmed the possibility of "radium" missiles from the front hemisphere, the first two launches of missiles with thermal GSN on parachute target M-6 at altitudes of 10 and 15 km.

In 1964, during tests of the T-58-98 complex, the results were obtained, which made it possible to give recommendations for adoption into service. In particular, there were 10 launches of telemetry missiles on targets M-6 and PM-4108, 13 launches of combat missiles (including seven K-8M-1) from the rear hemisphere on targets IL-28 and Yak-25 and seven - on IL-28 from the front hemisphere, all target aircraft were shot down. K-98 tests on Yak-28P were no less successful.

The missiles were equipped with new PARG-14VV homing radar heads, more suitable for low altitude applications. In particular, 14 launches on the IL-28 at altitudes of 500...700 m were successfully passed. All targets were also shot down during missile launches from the front hemisphere at altitudes from 7000 to 17000 m. Military tests with rocket launches on targets La-17 and MiG-17 were also successfully passed. The state tests were completed in June 1964.

In accordance with Resolution No 365-131 of 30 April 1965, the Su-15-98 interceptor complex based on the Su-15 interceptor (T-58-2) came into service with the RP-15 ("Eagle-DM") radar fitted with R-98 (K-98) missiles.  The missiles were suspended one under each wing console on PU-1-8 launchers. The usual version of the suspension included one missile R-98R with a semi-active homing radar head and one missile R-98T with a thermal homing head C1D-58. The missiles can be launched either by one or by volley.

For the first time in the USSR, R-98 missiles with semi-active radar allowed for use not only from the rear, but also from the front hemisphere of the target. In the latter case, at high altitudes, the launch range on targets at speeds up to 2000 km / h increased to 18 km with a target height of 5 to 18 km. When launching the maximum target range remained at the same level - 14 km, which should have been expected with the same engine type PRD-25. At launches in the rear hemisphere for rockets with both types of CNS the altitude of application was provided from 500m to 23000 m. The target altitude could reach 3 km above the interceptor.

However, despite the adoption for service, to ensure the successful use of R-98 missiles, the complex required a number of modifications and additional tests carried out in 1965. 1967.

The next stage of improvement of Sukhoi Design Bureau's interceptors was initially linked to the new Korshun-58 radar and K-58 missiles ("item 57") with the PARG-16VV radial GSN and PRD-143 engine. However, due to delays in the development of the Korshun-58 in 1968, a decision was taken to introduce on the Su-15 an improved version of the Smerch-AS radar named Typhoon. The missile was renamed K-98M, retaining the "unclassified" designation of "item 57".

The factory tests of the new version of the plane, named Su-15T, carried out since January 1969, revealed the need to improve the onboard radar. An Su-15TM aircraft with the Typhoon-M radar was already presented for state testing, which started in August 1970.  In April 1973, the state trials were completed with a recommendation to adopt the aircraft for service.

On 21th January 1975, pursuant to Decree No. 72-26, a new modification of the interceptor was adopted for service and officially received the name of the Su-15TM, with the radar being the RP-26. The improved K-98M missiles received the index P-98M.

The K-98Ms were characterised by enhanced noise immunity of the GSN and an extended launch range. The minimum launch altitude of the R-98MT compared to the R-98T in the front hemisphere decreased from 5,000 to 2,000 m, and the maximum altitude increased from 18,000 to 21,000 m (in the rear hemisphere - from 23,000 to 24,000 m).

Missiles were used on the Su-11, Su-15TM, Su-15UM and Su-17M fighter-interceptors (P-98MT only).

R-98 missiles under difficult weather conditions and at night were shot down by South Korean "Boeing" missiles, which violated the air border of the USSR in 1978 and 1983. The first of these missiles hit the Kola Peninsula in the clouds and the damaged plane was able to make a forced landing (and in the fever of the attack, the Su-15 pilot, who saw the Boeing 707 only on the radar screen, fired the remaining missile at the "detached second target" - the broken wing console of the intruder). The second, a Boeing 747, fired both heat and radium missiles from a distance of 11 km at night, hitting the fuselage and one of the engines.