The Bisnovat (later Molniya) R-4 (NATO reporting name AA-5 'Ash') was an early Soviet long-range air-to-air missile. It was used primarily as the sole weapon of the Tupolev Tu-128 interceptor, matching its RP-S Smerch ('Tornado') radar.
Development of the R-4 began in 1959, initially designated as K-80 or R-80, entering operational service around 1963, together with Tu-128.[1] Like many Soviet weapons, it was made in both semi-active radar homing (R-4R) and infrared-homing (R-4T) versions.[2] Standard Soviet doctrine was to fire the weapons in SARH/IR pairs to increase the odds of a hit.[3] Target altitude was from 8 to 21 km. Importantly for the slow-climbing Tu-128, the missile could be fired even from 8 km below the target.
In 1973 the weapon was modernized to R-4MR (SARH) / MT (IR) standard, with lower minimal target altitude (0.5–1 km),[4] improved seeker performance, and compatibility with the upgraded RP-SM Smerch-M radar.
The R-4 survived in limited service until 1990, retiring along with the last Tu-128 aircraft.[1]
